Open access peer-reviewed chapter

Schiff Bases and Their Metal Complexes: Synthesis, Structural Characteristics and Applications

Written By

Ramhari Meena, Pooja Meena, Anita Kumari, Naveen Sharma and Nighat Fahmi

Submitted: September 23rd, 2022 Reviewed: September 30th, 2022 Published: February 23rd, 2023

DOI: 10.5772/intechopen.108396

Chapter metrics overview

20 Chapter Downloads

View Full Metrics

Abstract

The development of Schiff base was a major step forward in the area of coordination chemistry. Schiff bases, a class of organic compounds, carry the imine or azomethine (>C=N–) functional group. Schiff bases played an influencing role in the development of coordination chemistry and were a key point in the development of inorganic, bioinorganic chemistry and optical materials. Schiff bases, widely used in inorganic, organic, and analytical chemistry, account for a significant portion of the more commonly employed classes of organic molecules. The ability of Schiff base ligands to form stable metal complexes with a wide range of transition and other metal ions makes them extremely useful. Condensation of a primary amine with an aldehyde or ketone yields a Schiff bases. In this chapter, we focused on introducing Schiff bases, classified them and their metal complexes, and discussed several synthesis methods, including conventional and green approaches. This chapter also elaborated on the industries’ applications, such as the food industry, agrochemical industry, dye industry, analytical chemistry, catalysis, energy storage, environmental, chemo-sensing, bio-sensing, and biomedical applications of novel Schiff bases and their metal complexes.

Keywords

  • Schiff base
  • metal complexes
  • synthesis
  • structure
  • industrial and biomedical applications

1. Introduction

Hugo Schiff, a German chemist, initially reported Schiff base in 1864 [1]. Schiff bases are organic molecules formed via condensation reaction of carbonyl compounds and primary amines [2]. The typical structure can be expressed as R’-CR = N-R”, where R, R’ and R” might vary. R and R’ could be alkyl, aryl and heterocyclic structures with various substituents. The carbonyl group may be a constituent of an aldehyde or a ketone (>C=O)). Because Schiff bases contain an azomethine (>C=N-)) group, they are also known as azomethine or imine. The Schiff bases derived from aldehydes and ketones are known as aldimines and ketimines, respectively. A general Schiff base condensation reaction involving the amine and the carbonyl functional group could be represented as follows (Figure 1).

Figure 1.

General scheme of formation of Schiff bases.

When synthesizing Schiff bases, nucleophilic amines are used to attack electrophilic carbonyl compounds via a nucleophilic addition process, forming a hemi-aminal group, and then the hemi-aminal group is dehydrated to generate imine compounds. In the first phase of the reaction, the amine reacts with the aldehyde or ketone to generate the unstable addition product carbinolamine. Carbinolamine undergoes acid- or base-catalyzed dehydration. Considering that carbinolamine is an alcohol, it undergoes a dehydration reaction when subjected to an acid catalyst (Figure 2). Reversible acid or base catalysis or heating often happens during the production of a Schiff base from aldehydes or ketones. When the product is isolated or water is evaporated, or both, the formation is pushed to completion. Hydrolysis of various Schiff bases by an aqueous acid or base yields the corresponding aldehydes, ketones, and amines.

Figure 2.

Mechanistic explanation of the formation of Schiff base.

Schiff bases with aryl substituents are significantly more stable and easier to synthesize, but those with alkyl substituents are relatively unstable [3, 4]. Aliphatic aldehyde Schiff bases are highly unstable and easily polymerizable, but aromatic aldehyde Schiff bases with efficient conjugation are more stable. Because aldehydes have less stearic hindrance than ketones, thus react faster. Extra carbon in ketones makes them less electrophilic than aldehydes. Schiff bases have received a great deal of attention due to their simplicity of synthesis, availability, and electronic characteristics. There is great interest in developing a wide range of applications in organic [5], inorganic [6, 7], coordination [8, 9, 10], bioinorganic [11, 12] and environmental chemistry [13, 14, 15, 16]. Schiff base derivatives have been utilized in medical, pharmaceutical, metal refining, metallurgy, catalysis, food, sensing, filtration, environmental, photography and diagnostic applications.

The discovery of Schiff base was a major step forward for the discipline of coordination chemistry. When combined with a variety of transition metal ions, Schiff base ligands can generate stable metal complexes with a wide range of applications. The Schiff base has remarkable chelating characteristics. The presence of hydroxyl and thio-groups in azomethine groups may result in forming a penta or hexa ring structure with metal ions. Bidentate, tridentate, tetradentate, and polydentate Schiff bases are also possible. Because of the availability of a lone pair on the nitrogen atom, the Schiff base forms complexes with many metals. This lone pair aids in creating monodentate complexes, while adding other groups, such as OH and SH, may result in the formation of bidentate chelates. The azomethine nitrogen atom’s lone pair of electrons and sp2 hybridized. As a result, it has substantial biological and chemical significance. Because there are more donor atoms in heterocyclic rings containing Schiff bases, they play a larger role in coordination chemistry [17, 18, 19].

Schiff bases show biological activities like nematicidal [20], insecticidal [21], antibacterial [22], antifungal [23], antileukaemia [24], anti-inflammatory [25], anti-HIV activity [26], antimycobacterial activity [27], antioxidant [28], anticancer [29], and plant growth regulatory activity [30] among others. Besides biological applications, Schiff base and their metal complexes have enormous applications in analytical chemistry [31], dye industry [32], and corrosion inhibitors [33]. Schiff base has attracted the attention of many experimental and theoretical researchers due to their particular photo-luminescence [34] in the visible range and at room temperature and so applied in many realms such as microelectronics [35], optoelectronics [36] and biological sensors [37]. Schiff base shows excellent catalytic activity in various reactions such as polymerization reaction and reduction of thionyl chloride, reduction reaction of ketones, oxidation of organic compounds, aldol reaction, epoxidation of alkenes, hydrosilylation of ketones, Henry reaction, synthesis of bis (indolyl) methanes and Diels Alder reaction [38, 39, 40]. Synthetic chemists have used Schiff bases and related complexes for a wide variety of processes, including the oxidation of alkenes and the catalytic transformation of hydrocarbons into useful oxygenated derivatives such alcohols, aldehydes, and epoxides. A further area of intense curiosity is the catalysis of alkene oxidation by soluble transition metal complexes. Schiff bases have a wide range of donor sites, resulting in significant transition metal complexes. Schiff base metal complexes have been used in biological applications, resulting in important recent improvements in a variety of chemistry areas. Because of their unique treatment method, metal-containing antibacterial compounds appear to be promising candidates for brand-new antibiotic medications that restrict the growth of bacterial strains. The characteristics of Schiff base metal complexes vary depending on the ligands and the transition metal ion. Schiff bases have attracted a lot of interest because of their various chemical and physical properties, as well as their ease of production.

Advertisement

2. Synthetic methods of Schiff bases

Schiff base ligands, a class of molecules having imine groups, have grown in popularity due to their physiological and pharmacological properties. They are a fascinating class of chelating agents capable of coordinating metal ions in a complex, which is used to imitate biological processes. Many studies have been conducted on synthesizing Schiff bases [41, 42, 43]. Schiff bases have been prepared using conventional and green synthetic methods (Figure 3).

Figure 3.

Synthetic methods of Schiff bases.

Heat is required in many condensation processes, and traditional reaction conditions often involve heating the reactants in a metal, oil, or sand bath for hours or even days. The conventional procedure involves refluxing or stirring different aldehydes or ketones with various types of primary amines. Green chemistry refers to the tools and procedures that provide considerable environmental and financial benefits over conventional synthetic approaches. It depicts that the current in green chemistry has triggered a new demand for organic synthesis in which distinct reaction environments must be located, reducing the usage of harmful organic solvents or toxic chemicals. Green approaches must improve selectivity, reduce reaction time, and simplify product isolation over conventional methods. Microwave-assisted synthesis of Schiff bases has been carried out without solvent or low-solvent conditions and reduces reaction time significantly, improves conversion, and sometimes increases selectivity. Since the development of solvent less microwave synthesis of Schiff bases, it has become the most well-known and simple technique for these reactions and is used in various applications. Many researchers reported using the microwave-assisted synthesis of various types of Schiff bases and their derivatives.

The grindstone technique reaction creates local heat by grinding substrate crystals and reagent with a mortar and pestle. Grinding starts reactions by transmitting a relatively small quantity of energy through friction. In some circumstances, a mixture and reagents form a glassy substance. Such reactions are simple to handle, eliminate pollutants, are relatively cheaper to operate, and may be considered more economical and environmentally friendly in chemistry [18]. Because molecules in a crystal are organized tightly and regularly, solid-state reactions are more efficient and selective than solution reactions [19]. The synthesis of amino acid Schiff bases (3) in water by the reaction of variously substituted aromatic aldehydes/heterocyclic aldehydes (2) and dl -alanine amino acid (1) stirring at room temperature (method A) using grindstone chemistry (method B), microwave irradiation (method C), and conventional heating (method D). Studies comparing the times required to synthesize four distinct Schiff bases under four different conditions found that while method B (grindstone) had a better product yield, it also took significantly longer than procedures A, C, and D., i.e., Product yields ranged from 72 to 78% after being subjected to grinding for 30–35 minutes followed by leaving the reaction mixture overnight (8 h). Product yields of 69–73% were achieved in 40–45 minutes when the reactants were stirred in water at room temperature (15–20°C). Microwave irradiation (method C) and ordinary heating (method D) were also used to synthesize compounds. In 5–6 minutes, yields of 70–72% were achieved under microwave irradiation, which is much quicker than grinding (method B). The highest yield and shortest reaction time were both achieved by using Method C (Figure 4).

Figure 4.

Synthesis of Schiff bases 3a–3f with different methods and comparisons [44].

Sonication is the use of high power to excite particles for various purposes. Ultrasonics with frequencies greater than 20 kHz is normally employed in a process known as ultrasonication [45]. In the laboratory, it is typically used with an ultrasonic bath or probe; this apparatus is known as a sonicator. A new approach for synthesizing Schiff bases under catalyst-free ultrasonic irradiation conditions has been discovered, yielding 92% compared to the current method’s 84% yield [46]. They discovered an efficient and environmentally friendly method for Schiff base synthesis in an aqueous solution using ultrasonic irradiation conditions and thus no catalyst. Several research publications revealed how different green synthesis techniques could cause a specific condensation process to occur preferentially. When opposed to solution-based synthesis, mechanochemical synthesis has the advantage of ease of set-up and high yields [47]. Most Schiff bases have reported more excellent ligation with metal ions because of a lone pair of electrons in these compounds. The number of transition and other metal ions complexes were synthesized by using novel Schiff base ligands [17].

Advertisement

3. Classification of Schiff bases and their metal complexes

By coordinating the d-block metal ion with the electron-donating ligand atom, a complex is created that modifies the metal’s steric and electrical properties. By doing so, the metal ion’s reactivity is stabilized and regulated, which is especially helpful for ions at higher oxidation states where they are less stable. Auxiliary ligands, or Schiff bases, are compounds that modify the structure and reactivity of a transition metal ion inside a complex. On the other hand, they do not incur any irreversible modifications, unlike reactive ligands. Atoms like nitrogen, sulfur, or oxygen can act as donors in the coordination process.

3.1 Denticity of Schiff base ligands

Schiff bases are classified into bidentate, tridentate, tetradentate, and polydentate ligands, which can form extremely stable complexes with transition metal ions (Figure 5). Assume they have different functional groups such as -OH, -NH2, or -SH; the resulting Schiff bases can act as mixed-donor ligands in bi-, tri-, tetra-, and higher coordination modes [48, 49, 50, 51]. Multivalent Schiff base ligands easily form complexes with bidentate, tridentate, and tetra- or polydentate metal ions at different oxidation states. Donor atoms (N, O, S) can be found in bidentate ligand (NN or ON), tridentate ligands (NNN, ONO, NNS or ONS), and tetradentate ligands (ONNO, NNNN, NSNO).

Figure 5.

Classification of Schiff bases into bidentate, tridentate, tetradentate, and polydentate ligands.

3.2 Symmetrical and asymmetrical Schiff bases

The Schiff bases’ great affinity for chelation towards inner and non-inner transition metal ions is employed to produce stable complexes. Unsymmetrical ligands do not have a rotation or mirror axis of symmetry and bind to a metal ion with two groups, and symmetrical ligands have [52, 53]. It has been argued that unsymmetrical Schiff base ligands are superior to their symmetrical counterparts due to their ability to more accurately predict the geometry of metal ion binding sites in biological systems that contain metal ions and their ability to more easily combine natural and synthetic structural components (Figure 6).

Figure 6.

Symmetrical and asymmetrical salphen Schiff bases.

3.3 Homoleptic and heteroleptic Schiff base metal complexes

The primary distinction between homoleptic [54] and heteroleptic [55] complexes is that homoleptic complexes have identical ligands linked to a metal centre. In contrast, heteroleptic complexes have at least one distinct ligand coupled to the complex’s metal centre (Figure 7).

Figure 7.

Homoleptic and heteroleptic Schiff base metal complexes.

3.4 Mononuclear and polynuclear Schiff base metal complexes

A single metal atom or ion is contained within the most basic type of Schiff base metal complex, and it is surrounded by monodentate, bidentate, tridentate, and polydentate ligands. Polynuclear Schiff base metal complexes are attributed to the presence of two or more atoms of metal, or ions, co-ordinated within a single coordination sphere. The two atoms may be linked together by direct metal-metal bonds, bridging ligands, or all of these things. As versatile ligands, Schiff bases form various polynuclear metal complexes such as homonuclear and heteronuclear. These flexible ligands have the ability to act as monodentate, bidentate, or polydentate, and they can be engineered to produce mononuclear, dinuclear, or polynuclear metal-organic frameworks. It is possible to change the nuclearity of Schiff base complexes; for example, it is possible to synthesize either mono- or dinuclear complexes using nearly identical ligands and synthetic processes for both types of complexes (Figure 8).

Figure 8.

Mononuclear and polynuclear Schiff base metal complexes [56, 57, 58, 59, 60, 61].

3.5 Achiral and chiral Schiff base metal complexes

A chiral Schiff base metal complex is not superimposable with its own mirror image because the two structures are not identical in all respects. The mirror image of an achiral Schiff base metal complex is identical to the complex itself and can be superimposed on it. The phenomena of optical activity have traditionally been defined in terms of asymmetry and dissymmetry; however, the term chirality has recently superseded these earlier classifications. Chiral entities exist as two species with the same chemical constitution. The only way they are distinguishable from one another is that they have the opposite configuration of an object and the mirror image of that thing. Chemical compounds can be said to be stereoisomers if their chemical constitutions are same but their spatial arrangements of their atoms are different. Chiral refers to the property of molecules that prevents them from being brought into coincidence with their mirror copies by the use of stiff motions (Figure 9).

Figure 9.

Achiral, chiral, trans and cis Schiff base metal complexes [62, 63, 64, 65].

Advertisement

4. Application of Schiff bases and its metal complexes

Schiff bases and their metal complexes find widespread use in various industries and applications, including the food industry, the agrochemical industry, the dye industry, analytical chemistry, catalysis, energy storage, environmental, chemo-sensing, bio-sensing, nanotechnology, and biomedical applications.

4.1 Catalysis

Catalytic activity is enhanced in both homogeneous and heterogeneous reactions by Schiff base metal complexes. The ligands, coordination sites, and metal ions employed in a given compound determine its activity. Many different reactions, such as polymerization, ring-opening polymerization, oxidation, epoxidation, allylic alkylation, reduction of ketones, hydrazination of acetophenones, the Michael addition reaction, the decomposition of hydrogen peroxide, the annulation reaction, the Heck reaction, the carbonylation reaction, and the Diels-Alder reaction, have been used to critically evaluate the catalytic activity of metal complexes. There is significant potential for Schiff base ligands to be used as metal complexes in catalysis due to their simple synthesis method and heat stability. The catalytic activity of Schiff base complexes differed greatly depending on the structure and kind of ligands used [66, 67].

4.2 Dye industry

The dyeing technique employs a wide range of Schiff bases and complexes, many of which have been synthesized, investigated, and employed as mordants [68]. As a dye, transition metal complexes such as iron (III), nickel (II), cobalt (II), and copper (II) complexes, among others, have been prepared from a variety of Schiff bases and employed to produce a variety of transition metal complexes. Aldehyde groups that include azo dyestuff are known to synthesized many azomethine linkages that contain azo dyes due to condensation with primer amines. The textile industry utilizes these dyestuffs to color a variety of materials. Outside the textile sector, the field of photochemistry places a significant emphasis on using azo dyes that include the amine group. The Schiff base on fluorene showed desirable properties including sensitivity to pH, as well as heat and color stability. For making a water-based ink, it showed promise as a functional pigment material [69].

4.3 Food industry

Various research groups have recently concentrated on producing natural novel and active materials for food packaging applications. Because of their antibacterial action, chitosan-derived Schiff base films developed may not only boost the safety of such foods and hence lengthen their shelf life, but also provide a flavor that is well-accepted by the consumer. Schiff’s base (SB) modified zirconium dioxide reinforced PLA bio-composite film serves as an alternate packing material to replace single waste synthetic manufactured materials that pollute the environment. For active packaging applications, Schiff base (SB) modified polylactic acid (PLA) film can provide improved barrier and antifungal qualities [70, 71, 72].

4.4 Agrochemical industry

Metal complexes with diverse Schiff base ligands have attracted the attention of chemists in recent years due to their agricultural applications, such as pesticidal, nematicidal, and insecticidal. Unsymmetrical Schiff bases glyoxal salicylaldehyde succinic acid dihydrazide and its Ni(II), Co(II), Zn(II), and Cu(II) complexes have been synthesized and studied; at greater concentrations, they display considerable insecticidal action [73]. H2L [2, 2′-[(1E, 2E)-ethane-1,2- diylidenedi (E) azanylylidene] dibenzenethiol] and its new Zn(II), Ni(II) metal complexes have been employed as insect repellent agents [74]. Coumarin-based Schiff base and its earth metal complexes [75] have been used to treat pests (Tribolium castaneu) and worms (Meloidogyne incognita).

4.5 Analytical applications

Schiff bases have been used as analytical probes or reagents by researchers. These are used to analyze primary amines, carbonyl compounds, and functional groups. In complexes, azomethine bonds are formed through complex formation reactions or changes in their spectroscopic properties caused by pH and solvent variations (pH of solvent polarity indicators). Schiff bases are a great carrier for the selective and efficient extraction of certain metal ions. They are well-known for their effective chelating capabilities. Schiff bases extract metal ions, essential in regulating heavy metal pollution. N, N -bis(3-methylsalicylidene)-ortho-phenylene diamine, Schiff base used in spectrophotometric detection of nickel. The approach has been used successfully to quantify trace quantities of nickel in natural food samples [76]. Schiff bases are renowned for their ability to form complexes and serve as good chelating ligands. They have been widely employed as analytical reagents due to their ligation property. Schiff bases made of salicylaldehyde are employed in gravimetric and spectrophotometric analyses. In addition, the same reagent was recently employed for the spectrophotometric detection of Ni (II) at a trace level. Cu2+ ions have been detected using the fluorescent 4-(1-phenyl-1-methylcyclobutane3-yl)-2-(2-hydroxy-5-bromobenzylidene) aminothiazole Schiff base. This chemical sensor operates in the visible region, has a wide dynamic operating range, and may be used over a wide pH range [77].

4.6 Energy storage

There is a resurgence of interest in the search for effective, clean, and sustainable energy sources (like wind and solar) as well as cutting-edge energy conversion and storage technologies as a result of the rapid growth of the world economy, the depletion of fossil fuels, and rising environmental pollution. Energy storage technologies are more important in our lives since the sun does not shine at night and the wind does not blow all the time. Currently, there is a lot of interest in electrical energy storage technologies including batteries and electrochemical capacitors (supercapacitors). Recent research has shown that organic oligomeric Schiff bases and electroactive polymeric (linear or hyperbranched) Schiff bases perform satisfactorily as negative electrodes (anodes) in sodium-ion batteries [78]. Lithium-ion batteries have also made use of nitrogen-rich carbon nanosheets produced by the Schiff base reaction in a molten salt solution as anode materials [79]. The linear polymeric Schiff bases developed by Armand et al. [80] as a consequence of the condensation of aromatic dialdehydes with aliphatic and aromatic diamines performed well as anodes for sodium-ion batteries. Polymeric Schiff bases are also produced by combining terephthalic-aldehyde, phenylenediamine, and polyether amine blocks, resulting in polymers with high adhesive qualities that can be used as redox-active binders for sodium-ion anodes. Similarly, Zhang et al. [81] developed another ImCOF (Imine bonds containing covalent organic frameworks) that performed again as an anode material for lithium-ion batteries derived from 2,4,6-triaminopyrimidine and terephthalaldehyde.

4.7 Environmental applications

Most firms worldwide need copper, silver, lead cadmium, aluminum and cobalt. These metals can be present in nearly all dairy products. Their widespread prevalence in industrial processes, chronic metal contamination from occupational contact, and health risks associated with these metals necessitate their identification and control in biological and dietary samples. Metals are used in electroplating, alloy production, and battery manufacturing. As a result, excessive metal concentrations have been discovered in diverse water sources, soil, and plants. Products such as cigarettes, beers, oils, and supplements necessitate metals monitoring and quality control [82].

Metal corrosion has a tremendous impact on the national economy and critical safety and pollution issues. Although many inhibitors have good inhibitory properties, they are insufficient for environmental protection and sustainable development initiatives for various reasons (such as difficulty in degradation, toxicity or high-temperature resistance). Stable, efficient, and ecologically friendly inhibitors are the inhibitors of the future. Many inhibitors, including imidazolines, Mannich bases, and Schiff bases, contain heteroatoms (N, S, O) or chemical interactions with electrons (p bonds). N, O, and S heteroatoms, as well as unsaturated >C=N- bonds, can create strong and durable corrosion-inhibiting adsorption films on metal surfaces, demonstrating outstanding inhibitory effects. At the same time, Schiff base compounds are attractive to researchers due to their inexpensive cost, ease of synthesis and purification, strong water solubility, and low toxicity [83].

4.8 Chemo-sensing applications

Schiff base-based fluorescent probes have recently been invented for detecting and monitoring numerous hazardous analytes in biological systems. Schiff base compounds with nitrogen-oxygen-rich coordination as a receptor site provide a stable platform for fluorescence sensing with significant, visible color shifts. Detecting metal ions with diverse mechanisms in an accurate sample using Schiff base-based sensors is appealing currently. In the recent decade, Schiff base probes based on fluorescence live-cell imaging have been used to detect metal ions such as Co2+, Cu2+, Zn2+, Hg2+, Ag+, Al3+, and ClO ions [84, 85, 86].

4.9 Bio-sensing applications

Within cells, Schiff base compounds have been used as biosensors for H2O2, glucose, and Oncomarker CA-125 [87]. Evaluation of the sensitivity and specificity of the gold Schiff base complex-doped sol gel nano optical sensor for the detection of CA-125 in ovarian cancer patient samples was performed and compared to results obtained from samples taken from healthy women serving as a control group [88]. Sheta M. Sheta et al. created an ultrasensitive method of detecting human creatinine using a cerium(III)-isatin Schiff base complex as an optical sensor [89].

4.10 Biomedical applications

Schiff bases and their metal complexes have numerous applications in various biomedical pharmaceuticals such as antimicrobial, anti-malarial, anticancer, antiviral, anti-inflammatory, antioxidant, anticonvulsant, anti-anthelmintic, bioprinting, tissue regenerating, enzyme inhibition and drug delivery. In biological systems, the azomethine nitrogen of Schiff bases serves as a binding site for metal ions to attach to diverse biomolecules such as proteins and amino acids for anti-germ activity. Our bodies’ Schiff bases catalyzed many metabolic events in the form of enzymes that are active against certain bacteria. Several studies have been conducted to improve the bio-functions of Schiff bases and their metal complexes. Schiff bases can fight cancer, fungus, germs, ulcers, and viruses, depending on which transition metal ions they contain [90, 91, 92].

Advertisement

5. Conclusion

Schiff bases and their metal complexes formed are the essential components of coordination and bioinorganic chemistry. The food industry, the agrochemical industry, the dye industry, analytical chemistry, catalysis, energy storage, the environmental field, chemo-sensing, bio-sensing, and the biomedical sector are some of the domains in which these have been used. This chapter discusses the conventional synthesis and environmentally friendly synthesis, as well as the categorization of Schiff bases and their metal complexes. Research into its applications in other fields of interest, such as catalysis, metal ion sensing, and cell imaging, makes its study relevant and worthy of being pursued.

References

  1. 1. Schiff H. Mittheilungen aus dem Universitats-laboratorium in Pisa (a report from the University Laboratory in Pisa). Justus Liebigs Annalen der Chemie. 1864;131:118-119
  2. 2. Jain S, Rana M, Sultana R, Mehandi R, Rahisuddin. Schiff Base metal complexes as antimicrobial and anticancer agents. Polycyclic Aromatic Compounds. 2022;5:1-56. DOI: 10.1080/10406638.2022.2117210
  3. 3. Hussain Z, Yousif E, Ahmed A, Altaie A. Synthesis and characterization of Schiff’s bases of sulfamethoxazole. Organic and Medicinal Chemistry Letters. 2014;4(1):1-4
  4. 4. Da Silva CM, da Silva DL, Modolo LV, Alves RB, de Resende MA, Martins CV, et al. Schiff bases: A short review of their antimicrobial activities. Journal of Advanced Research. 2011;2(1):1-8. DOI: 10.1016/j.jare.2010.05.004
  5. 5. Jain A, De S, Barman P. Microwave-assisted synthesis and notable applications of Schiff-base and metal complexes: A comparative study. Research on Chemical Intermediates. 2022;48(5):2199-2251. DOI: 10.1007/s11164-022-04708-7
  6. 6. Ghobakhloo F, Azarifar D, Mohammadi M, Keypour H, Zeynali H. Copper (II) schiff-base complex modified UiO-66-NH2 (Zr) metal–organic framework catalysts for Knoevenagel condensation–Michael addition–Cyclization reactions. Inorganic Chemistry. 2022;61(12):4825-4841. DOI: 10.1021/acs.inorgchem.1c03284
  7. 7. Jasim SA, Riadi Y, Majdi HS, Altimari US. Nanomagnetic macrocyclic Schiff-base–Mn (ii) complex: An efficient heterogeneous catalyst for click approach synthesis of novel β-substitued-1, 2, 3-triazoles. RSC Advances. 2022;12(28):17905-17918. DOI: 10.1039/d2ra02587f
  8. 8. Kargar H, Fallah-Mehrjardi M, Behjatmanesh-Ardakani R, Munawar KS, Ashfaq M, Tahir MN. Synthesis, spectral characterization, SC-XRD, HSA, DFT and catalytic activity of a dioxidomolybdenum complex with aminosalicyl-hydrazone Schiff base ligand: An experimental and theoretical approach. Polyhedron. 2021;208:115428. DOI: 10.1016/j.poly.2021.115428
  9. 9. Mohamed GG, Omar MM, Moustafa BS, AbdEl-Halim HF, Farag NA. Spectroscopic investigation, thermal, molecular structure, antimicrobial and anticancer activity with modelling studies of some metal complexes derived from isatin Schiff base ligand. Inorganic Chemistry Communications. 2022;141:109606. DOI: 10.1016/j.inoche.2022.109606
  10. 10. Aragón-Muriel A, Reyes-Márquez V, Cañavera-Buelvas F, Parra-Unda JR, Cuenú-Cabezas F, Polo-Cerón D, et al. Pincer complexes derived from tridentate Schiff bases for their use as antimicrobial Metallopharmaceuticals. Inorganics. 2022;10(9):134. DOI: 10.3390/inorganics10090134
  11. 11. Shahraki S. Schiff base compounds as artificial metalloenzymes. Colloids and Surfaces B: Biointerfaces. 2022;218:112727. DOI: 10.1016/j.colsurfb.2022.112727
  12. 12. Rangaswamy J, Ankali KN, Naik N, Nuthan BR, Satish S. The Mn (II), Co (II), Ni (II) and Cu (II) complexes of (Z)-N’((1H-indol-3-yl) methylene) nicotinohydrazide Schiff base: Synthesis, characterization and biological evaluation. Journal of the Iranian Chemical Society. 2022;19:3993-4004. DOI: 10.1007/s13738-022-02580-1
  13. 13. Farag AA, Toghan A, Mostafa MS, Lan C, Ge G. Environmental remediation through catalytic inhibition of steel corrosion by Schiff’s bases: Electrochemical and biological aspects. Catalysts. 2022;12(8):838. DOI: 10.3390/catal12080838
  14. 14. Liu H, Ding S, Lu Q , Jian Y, Wei G, Yuan Z. A versatile Schiff Base Chemosensor for the determination of trace Co2+, Ni2+, Cu2+, and Zn2+ in the water and its bioimaging applications. ACS Omega. 2022;7(9):7585-7594. DOI: 10.1021/acsomega.1c05960
  15. 15. Paul A, Silva TA, Soliman MM, Karačić J, Šljukić B, Alegria EC, et al. Benzimidazole Schiff base copper (II) complexes as catalysts for environmental and energy applications: VOC oxidation, oxygen reduction and water splitting reactions. International Journal of Hydrogen Energy. 2022;47(55):23175-23190. DOI: 10.1016/j.ijhydene.2022.04.271
  16. 16. Verma C, Quraishi MA, Alfantazi A, Rhee KY. Corrosion inhibition potential of chitosan based Schiff bases: Design, performance and applications. International Journal of Biological Macromolecules. 2021;184:135-143. DOI: 10.1016/j.ijbiomac.2021.06.049
  17. 17. Yadav M, Sharma S, Devi J. Designing, spectroscopic characterization, biological screening and antioxidant activity of mononuclear transition metal complexes of bidentate Schiff base hydrazones. Journal of Chemical Sciences. 2021;133(1):1-22. DOI: 10.1007/s12039-020-01854-6
  18. 18. Singh A, Gogoi HP, Barman P, Guha AK. Novel thioether Schiff base transition metal complexes: Design, synthesis, characterization, molecular docking, computational, biological and catalytic studies. Applied Organometallic Chemistry. 2022;36:66-73. DOI: 10.1002/aoc.6673
  19. 19. Dhingra N, Singh JB, Singh HL. Synthesis, spectroscopy, and density functional theory of organotin and organosilicon complexes of bioactive ligands containing nitrogen, sulfur donor atoms as antimicrobial agents: In vitro and in silico studies. Dalton Transactions. 2022;51:8821-8831. DOI: 10.1039/D2DT01051H
  20. 20. Abd El-Hamid SM, Sadeek SA, El-Farargy AF, Abd El-Lattif NS. Synthesis, structural characterization and nematicidal studies of some new N2O2 Schiff base metal complexes. Bulletin of the Chemical Society of Ethiopia. 2021;35(2):315-335. DOI: 10.4314/bcse.v35i2.12
  21. 21. Alanazi MA, Arafa WA, Althobaiti IO, Altaleb HA, Bakr RB, Elkanzi NA. Green design, synthesis, and molecular docking study of novel Quinoxaline derivatives with insecticidal potential against Aphis craccivora. ACS Omega. 2022;7(31):27674-27689. DOI: 10.1021/acsomega.2c03332
  22. 22. El-Gammal OA, Mohamed FS, Rezk GN, El-Bindary AA. Synthesis, characterization, catalytic, DNA binding and antibacterial activities of Co (II), Ni (II) and Cu (II) complexes with new Schiff base ligand. Journal of Molecular Liquids. 2021;326:115223. DOI: 10.1016/j.molliq.2020.115223
  23. 23. Wei L, Zhang J, Tan W, Wang G, Li Q , Dong F, et al. Antifungal activity of double Schiff bases of chitosan derivatives bearing active halogeno-benzenes. International Journal of Biological Macromolecules. 2021;179:292-298. DOI: 10.1016/j.ijbiomac.2021.02.184
  24. 24. Iraji M, Salehi M, Malekshah RE, Khaleghian A, Shamsi F. Liposomal formulation of new arsenic schiff base complex as drug delivery agent in the treatment of acute promyelocytic leukemia and quantum chemical and docking calculations. Journal of Drug Delivery Science and Technology. 2022;75:103600. DOI: 10.1016/j.jddst.2022.103600
  25. 25. Hamid SJ, Salih T. Design, synthesis, and anti-inflammatory activity of some Coumarin Schiff Base derivatives: In silico and in vitro study. Drug Design, Development and Therapy. 2022;16:2275. DOI: 10.2147/DDDT.S364746
  26. 26. Al-Masoudi NA, Aziz NM, Mohammed AT. Synthesis and in-vitro anti-hiv activity of some new schiff base ligands derived from 5-amino-4- phenyl-4h-1,2,4-triazole-3-thiol and their metal complexes. Phosphorus, Sulfur, and Silicon. 2009;184(11):2891-2901. DOI: 10.1080/10426500802591630
  27. 27. Meeran IS, Raja TW, Dusthakeer VA, Ali MM, Tajudeen SS, Shabeer TK. An insight into antimycobacterial and antioxidant potentials of INH-Schiff base complexes and in silico targeting of MtKasB receptor of M. tuberculosis. New Journal of Chemistry. 2022;46(10):4620-4633. DOI: 10.1039/D1NJ04977A
  28. 28. Ali MA, Musthafa SA, Munuswamy-Ramanujam G, Jaisankar V. 3-Formylindole-based chitosan Schiff base polymer: Antioxidant and in vitro cytotoxicity studies on THP-1 cells. Carbohydrate Polymers. 2022;290:119501. DOI: 10.1016/j.carbpol.2022.119501
  29. 29. Daravath S, Rambabu A, Ganji N, Ramesh G, Lakshmi PA. Spectroscopic, quantum chemical calculations, antioxidant, anticancer, antimicrobial, DNA binding and photo physical properties of bioactive Cu (II) complexes obtained from trifluoromethoxy aniline Schiff bases. Journal of Molecular Structure. 2022;1249:131601. DOI: 10.1016/j.molstruc.2021.131601
  30. 30. Mane VA, Palande SV, Swamy DK. In vitro antimicrobial activity and plant growth activity study of schiff base ligand (e)-2, 4-diromo-6-{[(2-(2-methoxyphenoxy) ethyl] iminomethyl} phenol and their complexes with transition metals. Journal of Advanced Scientific Research. 2021;12(01 Suppl 2):271-282. DOI: 10.55218/ASR.s12021121sup205
  31. 31. Kaur P, Singh R, Kaur V, Talwar D. Anthranilic acid Schiff base as a fluorescent probe for the detection of arsenite and selenite: A detailed investigation of analytical parameters and mechanism for interaction. Analytical Sciences. 2021;37(4):553-560. DOI: 10.2116/analsci.20P102
  32. 32. Refat MS, Saad HA, Gobouri AA, Alsawat M, Adam AM, El-Megharbel SM. Charge transfer complexation between some transition metal ions with azo Schiff base donor as a smart precursor for synthesis of nano oxides: An adsorption efficiency for treatment of Congo red dye in wastewater. Journal of Molecular Liquids. 2022;345:117140. DOI: 10.1016/j.molliq.2021.117140
  33. 33. Saha SK, Murmu M, Murmu NC, Banerjee P. Synthesis, characterization and theoretical exploration of pyrene based Schiff base molecules as corrosion inhibitor. Journal of Molecular Structure. 2021;1245:131098. DOI: 10.1016/j.molstruc.2021.131098
  34. 34. Zhao ZG, Kodaira T, Nagai N, Hakuta Y, Bando KK, Takashima H, et al. Self-standing microporous films of arrayed alumina nano-fibers including Schiff base molecules: Effect of the environment around the molecules on their photo-luminescence. Journal of Materials Chemistry. 2012;22(19):9738-9744. DOI: 10.1039/C2JM15798E
  35. 35. Yan-Yan LI, Yu-Xi YA, Sha-Sha HO, Yao LI, Zhi YA, Bin-Yu ZH, et al. An electrochemical sensor based on redox-active Schiff Base polymers for simultaneous sensing of glucose and pH. Chinese Journal of Analytical Chemistry. 2021;49(6):e21118-e21125. DOI: 10.1016/S1872-2040(21)60107-X
  36. 36. Upendranath K, Venkatesh T, Nayaka YA, Shashank M, Nagaraju G. Optoelectronic, DFT and current-voltage performance of new Schiff base 6-nitro-benzimidazole derivatives. Inorganic Chemistry Communications. 2022;139:109354. DOI: 10.1016/j.inoche.2022.109354
  37. 37. Kumar J, Sarma MJ, Phukan P, Das DK. A new simple Schiff base fluorescence “on” sensor for Al 3+ and its living cell imaging. Dalton Transactions. 2015;44(10):4576-4581. DOI: 10.1039/C4DT03932G
  38. 38. Spassky N, Wisniewski M, Pluta C, Le Borgne A. Highly stereoelective polymerization of rac-(D, L)-lactide with a chiral schiff’s base/aluminium alkoxide initiator. Macromolecular Chemistry and Physics. 1996;197(9):2627-2637. DOI: 10.1002/macp.1996.021970902
  39. 39. Kim WS, Choi YK. Electrocatalytic effects of thionyl chloride reduction by polymeric Schiff base transition metal (II) complexes. Applied Catalysis A: General. 2003;252(1):163-172. DOI: 10.1016/S0926-860X(03)00414-9
  40. 40. Satheesh CE, Sathish Kumar PN, Kumara PR, Karvembu R, Hosamani A, Nethaji M. Half-sandwich Ru (II) complexes containing (N, O) Schiff base ligands: Catalysts for base-free transfer hydrogenation of ketones. Applied Organometallic Chemistry. 2019;33(10):e5111. DOI: 10.1002/aoc.5111
  41. 41. Haque J, Srivastava V, Chauhan DS, Lgaz H, Quraishi MA. Microwave-induced synthesis of chitosan Schiff bases and their application as novel and green corrosion inhibitors: Experimental and theoretical approach. ACS Omega. 2018;3(5):5654-5668. DOI: 10.1021/acsomega.8b00455
  42. 42. Nikpassand M, Fekri LZ, Sharafi S. An efficient and green synthesis of novel azo Schiff base and its complex under ultrasound irradiation. Oriental Journal of Chemistry. 2013;29(3):1041-1046. DOI: 10.13005/ojc/290326
  43. 43. Shukla M, Kulshrashtha H, Seth DS. Comparative study of the schiff bases by conventional and green method and antimicrobial activity. International Journal of Materials Sciences. 2017;12(1):71-76
  44. 44. Sachdeva H, Saroj R, Khaturia S, Dwivedi D. Operationally simple green synthesis of some Schiff bases using grinding chemistry technique and evaluation of antimicrobial activities. Green Processing and Synthesis. 2012;1(5):469-477. DOI: 10.1515/gps-2012-0043
  45. 45. Kargar H, Fallah-Mehrjardi M, Behjatmanesh-Ardakani R, Torabi V, Munawar KS, Ashfaq M, et al. Sonication-assisted synthesis of new Schiff bases derived from 3-ethoxysalicylaldehyde: Crystal structure determination, Hirshfeld surface analysis, theoretical calculations and spectroscopic studies. Journal of Molecular Structure. 2021;1243:130782. DOI: 10.1016/j.molstruc.2021.130782
  46. 46. Mittersteiner M, Farias FF, Bonacorso HG, Martins MA, Zanatta N. Ultrasound-assisted synthesis of pyrimidines and their fused derivatives: A review. Ultrasonics Sonochemistry. 2021;79:105683. DOI: 10.1016/j.ultsonch.2021.105683
  47. 47. Otani N, Furuya T, Katsuumi N, Haraguchi T, Akitsu T. Synthesis of amino acid derivative Schiff base copper (II) complexes by microwave and wet mechanochemical methods. Journal of the Indian Chemical Society. 2021;98(1):100004. DOI: 10.1016/j.jics.2021.100004
  48. 48. Meena DR, Aalam MJ, Chaudhary P, Yadav GD, Singh S. Synthesis and structural studies of Pd (II) complexes of bidentate Schiff bases and their catalytic activities as pre-catalysts in the Mizoroki-heck reaction. Polyhedron. 2022;222:115931. DOI: 10.1016/j.poly.2022.115931
  49. 49. Alfonso-Herrera LA, Rosete-Luna S, Hernández-Romero D, Rivera-Villanueva JM, Olivares-Romero JL, Cruz-Navarro JA, et al. Transition metal complexes with tridentate Schiff bases (O^ N^ O and O^ N^ N) derived from salicylaldehyde: An analysis of their potential anticancer activity. ChemMedChem. 2022;17:1-47. DOI: 10.1002/cmdc.202200367
  50. 50. Abdel-Rahman LH, Adam MS, Al-Zaqri N, Shehata MR, Ahmed HE, Mohamed SK. Synthesis, characterization, biological and docking studies of ZrO (II), VO (II) and Zn (II) complexes of a halogenated tetra-dentate Schiff base. Arabian Journal of Chemistry. 2022;15(5):103737. DOI: 10.1016/j.arabjc.2022.103737
  51. 51. Das S, Das M, Laha S, Rajak K, Choudhuri I, Bhattacharyya N, et al. Development of moderately fluorescence active salen type chemosensor for judicious recognition and quantification of Zn (II), Al (III) and SO4=: Demonstration of molecular logic gate formation and live cell images studies. Journal of Molecular Structure. 2022;1263:133214. DOI: 10.1016/j.molstruc.2022.133214
  52. 52. Li Y, Liu Y, Wei X, Wang L, Wang Y, Zhang Q. A symmetric Schiff base fluorescent “turn-on” chemosensor for aluminum (III) ion selective detection based on hydrolysis. Journal of Molecular Structure. 2022;1261:132884. DOI: 10.1016/j.molstruc.2022.132884
  53. 53. Chaudhary NK, Guragain B. Coordination chemistry, antibacterial screening, and In silico ADME study of mononuclear NiII and CuII complexes of asymmetric Schiff Base of streptomycin and aniline. Journal of Chemistry. 2022;2022:1-14. DOI: 10.1155/2022/3881217
  54. 54. Yusof EN, Latif MA, Tahir MI, Sakoff JA, Veerakumarasivam A, Page AJ, et al. Homoleptic tin (IV) compounds containing tridentate ONS dithiocarbazate Schiff bases: Synthesis, X-ray crystallography, DFT and cytotoxicity studies. Journal of Molecular Structure. 2020;1205:127635. DOI: 10.1016/j.molstruc.2019.127635
  55. 55. Dar OA, Lone SA, Malik MA, Wani MY, Talukdar MI, Al-Bogami AS, et al. Heteroleptic transition metal complexes of Schiff-base-derived ligands exert their antifungal activity by disrupting membrane integrity. Applied Organometallic Chemistry. 2019;33(11):e5128. DOI: 10.1002/aoc.5128
  56. 56. Abdel-Rahman LH, Abu-Dief AM, Adam MS, Hamdan SK. Some new nano-sized mononuclear Cu (II) Schiff base complexes: Design, characterization, molecular modeling and catalytic potentials in benzyl alcohol oxidation. Catalysis Letters. 2016;146(8):1373-1396. DOI: 10.1007/s10562-016-1755-0
  57. 57. Parasuraman B, Rajendran J, Rangappan R. An insight into antibacterial and anticancer activity of homo and hetero binuclear Schiff Base complexes. Oriental Journal of Chemistry. 2017;33(3):1223. DOI: 10.13005/OJC/330321
  58. 58. Puzari A, Borah D, Das P. Binuclear Pd (II) complexes with multidentate Schiff base ligands: Synthesis, catalysis, and antibacterial properties. Monatshefte für Chemie-Chemical Monthly. 2022;153:435-442. DOI: 10.1007/s00706-022-02929-5
  59. 59. Maiti SK, Bora A, Barman P, Chandra AK, Baidya B. Binuclear chiral Ni (II) complex of tridentate OON chiral Schiff base ligand, 1-((E)-(((1S, 2R)-2-hydroxy-2, 3-dihydro-1H-inden-1-yl) imino) methyl) naphthalen-2-ol. Journal of Coordination Chemistry. 2020;73(1):67-86. DOI: 10.1080/00958972.2019.1711069
  60. 60. Dey D, Kaur G, Ranjani A, Gayathri L, Chakraborty P, Adhikary J, et al. A trinuclear zinc–schiff base complex: Biocatalytic activity and cytotoxicity. European Journal of Inorganic Chemistry. 2014;2014(21):3350-3358. DOI: 10.1002/ejic.201402158
  61. 61. Mokolokolo PP, Frei A, Tsosane MS, Kama DV, Schutte-Smith M, Brink A, et al. Nuclearity manipulation in Schiff-base fac-tricarbonyl complexes of Mn (I) and Re (I). Inorganica Chimica Acta. 2018;471:249-256. DOI: 10.1016/j.ica.2017.10.036
  62. 62. Tang J, Yao P, Huang F, Luo M, Wei Y, Bian H. Stereoselective sulfoxidation catalyzed by achiral Schiff base complexes in the presence of serum albumin in aqueous media. Tetrahedron: Asymmetry. 2017;28(12):1700-1707. DOI: 10.1016/j.tetasy.2017.10.021
  63. 63. Roy GB. Synthesis and study of physico-chemical properties of a new chiral Schiff base ligand and its metal complex. Inorganica Chimica Acta. 2009;362(6):1709-1714. DOI: 10.1016/j.ica.2008.08.009
  64. 64. Ito M, Akitsu T, Palafox MA. Theoretical interpretation of polarized light-induced supramolecular orientation on the basis of normal mode analysis of azobenzene as hybrid materials in PMMA with chiral Schiff base Ni (II), Cu (II), and Zn (II) complexes. Journal of Applied Solution Chemistry and Modeling. 2016;5(1):30-47. DOI: 10.6000/1929-5030.2016.05.01.3
  65. 65. Sunaga N, Haraguchi T, Akitsu T. Orientation of chiral schiff base metal complexes involving azo-groups for induced cd on gold nanoparticles by polarized uv light irradiation. Symmetry. 2019;11(9):1094. DOI: 10.3390/sym11091094
  66. 66. Alshaheri AA, Tahir MI, Rahman MB, Begum T, Saleh TA. Synthesis, characterisation and catalytic activity of dithiocarbazate Schiff base complexes in oxidation of cyclohexane. Journal of Molecular Liquids. 2017;240:486-496. DOI: 10.1016/j.molliq.2017.05.081
  67. 67. Gupta KC, Sutar AK. Catalytic activities of Schiff base transition metal complexes. Coordination Chemistry Reviews. 2008;252(12-14):1420-1450. DOI: 10.1016/j.ccr.2007.09.005
  68. 68. Abuamer KM, Maihub AA, El-Ajaily MM, Etorki AM, Abou-Krisha MM, Almagani MA. The role of aromatic Schiff bases in the dyes techniques. International Journal of Organic Chemistry. 2014;4:7-15. DOI: 10.4236/ijoc.2014.41002
  69. 69. Kazemnejadi M, Dehno Khalaji A, Mighani H. Synthesis and characterization of Schiff-base polymer derived from 2, 5-dichloroaniline and 2-hydroxybenzaldehyde. Quarterly Journal of Iranian Chemical Communication. 2017;5(3):237-363. Serial No. 16):237-41
  70. 70. Higueras L, López-Carballo G, Gavara R, Hernández-Muñoz P. Reversible covalent immobilization of cinnamaldehyde on chitosan films via schiff base formation and their application in active food packaging. Food and Bioprocess Technology. 2015;8(3):526-538. DOI: 10.1007/s11947-014-1421-8
  71. 71. Mr SN, Srinivasan AK, Keerthana P, Kumar A. Schiff’s base (SB) modified zirconium dioxide reinforced PLA bio-composite film for industrial packaging applications. Composites Communications. 2021;25:100750. DOI: 10.1016/j.coco.2021.100750
  72. 72. Natesan S, Samuel JS, Srinivasan AK. Design and development of Schiff’s base (SB)-modified polylactic acid (PLA) antimicrobial film for packaging applications. Polymer Bulletin. 2022;79(7):4627-4646. DOI: 10.1007/s00289-021-03703-z
  73. 73. Singh S. Synthesis, spectroscopic studies and pesticidal activity of transition metal complexes with unsymmetrical schiff base. Indian Journal of Biochemistry and Biophysics (IJBB). 2021;58(6):565-571. DOI: 10.56042/ijbb.v58i6.57792
  74. 74. Karmakar I, Mandal S, Mitra A. Evaluation of antimicrobial and insect repellent properties of two novel zinc (II), and nickel (II) complexes containing a tetradentate Schiff Base. Journal of Integrated Science and Technology. 2015;3(2):60-67
  75. 75. Kapoor P, Singh RV, Fahmi N. Coordination chemistry of rare earth metal complexes with coumarin-based imines: Ecofriendly synthesis, characterization, antimicrobial, DNA cleavage, pesticidal, and nematicidal activity evaluations. Journal of Coordination Chemistry. 2012;65(2):262-277. DOI: 10.1080/00958972.2011.649265
  76. 76. Fakhari AR, Khorrami AR, Naeimi H. Synthesis and analytical application of a novel tetradentate N2O2 Schiff base as a chromogenic reagent for determination of nickel in some natural food samples. Talanta. 2005;66(4):813-817. DOI: 10.1016/j.talanta.2004.12.043
  77. 77. Aksuner N, Henden E, Yilmaz I, Cukurovali A. A highly sensitive and selective fluorescent sensor for the determination of copper (II) based on a schiff base. Dyes and Pigments. 2009;83(2):211-217. DOI: 10.1016/j.dyepig.2009.04.012
  78. 78. López-Herraiz M, Castillo-Martínez E, Carretero-González J, Carrasco J, Rojo T, Armand M. Oligomeric-Schiff bases as negative electrodes for sodium ion batteries: Unveiling the nature of their active redox centers. Energy & Environmental Science. 2015;8(11):3233-3241. DOI: 10.1039/C5EE01832C
  79. 79. Yang X, Zhuang X, Huang Y, Jiang J, Tian H, Wu D, et al. Nitrogen-enriched hierarchically porous carbon materials fabricated by graphene aerogel templated Schiff-base chemistry for high performance electrochemical capacitors. Polymer Chemistry. 2015;6(7):1088-1095. DOI: 10.1039/C4PY01408A
  80. 80. Castillo-Martínez E, Carretero-González J, Armand M. Polymeric Schiff bases as low-voltage redox centers for sodium-ion batteries. Angewandte Chemie International Edition. 2014;53(21):5341-5345. DOI: 10.1002/anie.201402402
  81. 81. Chen H, Zhang Y, Xu C, Cao M, Dou H, Zhang X. Two π-conjugated covalent organic frameworks with long-term Cyclability at high current density for lithium ion battery. Chemistry. A European Journal. 2019;25(68):15472-15476. DOI: 10.1002/chem.201903733
  82. 82. Oiye ÉN, Ribeiro MF, Katayama JM, Tadini MC, Balbino MA, Eleotério IC, et al. Electrochemical sensors containing schiff bases and their transition metal complexes to detect analytes of forensic, pharmaceutical and environmental interest. A review. Critical Reviews in Analytical Chemistry. 2019;49(6):488-509. DOI: 10.1080/10408347.2018.1561242
  83. 83. Wei W, Liu Z, Liang C, Han GC, Han J, Zhang S. Synthesis, characterization and corrosion inhibition behavior of 2-aminofluorene bis-Schiff bases in circulating cooling water. RSC Advances. 2020;10(30):17816-17828. DOI: 10.1039/D0RA01903H
  84. 84. Krishnan U, Iyer SK. Iminothiophenol Schiff base-based fluorescent probe for dual detection of Hg2+ and Cr3+ ions and its application in real sample analysis. Journal of Photochemistry and Photobiology A: Chemistry. 2022;425:113663. DOI: 10.1016/j.jphotochem.2021.113663
  85. 85. Bharali B, Talukdar H, Phukan P, Das DK. A new Schiff Base based fluorescent sensor for Al (III) based on 2-Hydroxyacetophenone and o-Phenylenediamine. Journal of Fluorescence. 2020;30(4):751-757. DOI: 10.1007/s10895-020-02527-w J
  86. 86. Yuan C, Liu X, Wu Y, Lu L, Zhu M. A triazole Schiff base-based selective and sensitive fluorescent probe for Zn2+: A combined experimental and theoretical study. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2016;154:215-219. DOI: 10.1016/j.saa.2015.10.035
  87. 87. Fatima B, Hussain D, Bashir S, Hussain HT, Aslam R, Nawaz R, et al. Catalase immobilized antimonene quantum dots used as an electrochemical biosensor for quantitative determination of H2O2 from CA-125 diagnosed ovarian cancer samples. Materials Science and Engineering: C. 2020;117:111296. DOI: 10.1016/j.msec.2020.111296
  88. 88. Abou-Omar MN, Attia MS, Afify HG, Amin MA, Boukherroub R, Mohamed EH. Novel optical biosensor based on a nano-gold coated by Schiff base doped in sol/gel matrix for sensitive screening of oncomarker CA-125. ACS Omega. 2021;6(32):20812-20821. DOI: 10.1021/acsomega.1c01974
  89. 89. Sheta SM, Akl MA, Saad HE, El-Gharkawy ES. A novel cerium (iii)–isatin Schiff base complex: Spectrofluorometric and DFT studies and application as a kidney biomarker for ultrasensitive detection of human creatinine. RSC Advances. 2020;10(10):5853-5863. DOI: 10.1039/C9RA10133K
  90. 90. Fahmi N, Shrivastava S, Meena R, Joshi SC, Singh RV. Microwave assisted synthesis, spectroscopic characterization and biological aspects of some new chromium (iii) complexes derived from N O donor Schiff bases. New Journal of Chemistry. 2013;37(5):1445-1453. DOI: 10.1039/C3NJ40907D
  91. 91. Sharma S, Meena R, Singh RV, Fahmi N. Synthesis, characterization, antimicrobial, and DNA cleavage evaluation of some organotin (IV) complexes derived from ligands containing the 1H-indole-2, 3-dione moiety. Main Group Metal Chemistry. 2016;39(1-2):31-40. DOI: 10.1515/mgmc-2015-0030
  92. 92. Kumari A, Meena R, Singh RV, Fahmi N. Synthesis, characterization, antimicrobial and DNA cleavage study of organoantimony (III) and organoarsenic (III) complexes with monofunctional bidentate Schiff base. Indian Journal of Chemistry. 2021;60:341-347

Written By

Ramhari Meena, Pooja Meena, Anita Kumari, Naveen Sharma and Nighat Fahmi

Submitted: September 23rd, 2022 Reviewed: September 30th, 2022 Published: February 23rd, 2023