Study the removal of fluoride from water by using chitin

Polymer is a large molecule (molecular weight ~10 000 or greater) composed of many smaller molecules (monomer) covalently bonded together. While the term polymer in popular usage suggests "plastic", polymers comprise a large class of natural and synthetic materials with a variety of properties purposes.Single polymer molecules typically have molecular weights between 10,000 and 1,000,000 g/mol--that can be more than 2000 repeating units depending on the polymer structure! The mechanical properties of a polymer are significantly affected by the molecular weight, with better engineering properties at higher molecular weights. The softening point (glass transition temperature) and the melting point of a polymer will determine which applications it will be suitable for. These temperatures usually determine the upper limit for which a polymer can be used. For example, many industrially polymers have glass transition temperatures near the boiling point of water (1000C, 212F), and they are most useful for room temperature applications. Some specially engineered polymers can withstand temperatures as high as 3000 C (572 F). Higher molecular weights. Polymers can be crystalline or amorphous, but they usually have a combination of crystalline and amorphous structures (semi-crystalline). The polymer chains can be free to slide past one another (thermoplastic) or they can be connected to each other with cross links (thermosets or elastomer). Thermoplastics can be reformed and recycled, while thermosets and elastomers are not rework able. The chemical structure of the chains also has a tremendous effect on the properties. Depending on the structure the polymer may be hydrophilic or hydrophobic (likes or hates water), stiff or flexible, crystalline or amorphous, reactive or uncreative

Chemistry of Oxomolybdenum Complexes with ON- and ONO- Donor Ligands

Chapter 1: In this chapter the scope of the present investigation is delineated briefly along with the aim of the work. Chapter 2: Reaction of benzoylhydrazone of 2-hydroxybenzaldehyde (H2L) with [MoO2(acac)2] proceeds smoothly in refluxing ethanol to afford an orange complex [MoO2L(C2H5OH)] (1). The substrate binding capacity of complex (1) has been demonstrated by the formation and isolation of two mononuclear [MoO2L(Q)] {where Q = imidazole (2a) and 1-methylimidazole (2b)} and one dinuclear [(MoO2L)2(Q)] {Q = 4,4'-bipyridine (3)} mixed-ligand oxomolybdenum complexes. All the complexes have been characterized by elemental analysis, electrochemical and spectroscopic (IR, UV–Vis and NMR) measurements. Molecular structures of all the oxomolybdenum(VI) complexes (1, 2a, 2b and 3) have been determined by X-ray crystallography. The complexes have been screened for their antibacterial activity against Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. The minimum inhibitory concentration of these complexes and antibacterial activity indicates the compound 2a and 2b as the potential lead molecule for drug designing. Chapter 3: Reaction of the salicyloylhydrazone of 2-hydroxy-1-naphthaldehyde (H2L1), anthranylhydrazone of 2-hydroxy-1-naphthaldehyde (H2L2), benzoylhydrazone of 2-hydroxy-1-acetonaphthone (H2L3) and anthranylhydrazone of 2-hydroxy-1-acetonaphthone (H2L4; general abbreviation H2L) with [MoO2(acac)2] afforded a series of 5- and 6- coordinate Mo(VI) complexes of the type [MoO2L1–2(ROH)] [where R = C2H5 (1) and CH3 (2)], and [MoO2L3–4] (3 and 4). The substrate binding capacity of 1 has been demonstrated by the formation of one mononuclear mixed-ligand dioxomolybdenum complex [MoO2L1(Q)] {where Q = γ-picoline (1a)}. Molecular structure of all the complexes (1, 1a, 2, 3 and 4) is determined by X-ray crystallography, demonstrating the dibasic tridentate behavior of ligands. All the complexes have been characterized by elemental analysis, electrochemical and spectroscopic (IR, UV–Vis and vi NMR) measurements. The complexes have been screened for their antibacterial activity against Escherichia coli, Bacillus subtilis, Proteus vulgaris and Klebsiella pneumoniae. The minimum inhibitory concentration of these complexes and antibacterial activity indicates 1 and 1a as the potential lead molecule for drug designing. Catalytic potential of these complexes was tested for the oxidation of benzoin using 30% aqueous H2O2 as an oxidant in methanol. At least four reaction products benzoic acid, benzaldehyde-dimethylacetal, methylbenzoate and benzil were obtained with the 95-99% conversion under optimized reaction conditions. Oxidative bromination of salicylaldehyde, a functional mimic of haloperoxidases, in aqueous H2O2/KBr in the presence of HClO4 at room temperature has also been carried out successfully. Chapter 4: Report of synthesis and characterization of two novel dimeric [(MoVIO2)2L] (1) and tetrameric [{(C2H5OH)LO3Mo2VI}2(-O)2]·C2H5OH (2) dioxomolybdenum(VI) complexes with N,N'-disalicyloylhydrazine (H2L), which is formed by the self combination of salicyloyl hydrazide. Both the complex was characterized by various spectroscopic techniques (IR, UV–Vis and NMR) and also by electrochemical study. The molecular structures of both the complexes have been confirmed by X-ray crystallography. All these studies indicate that the N,N'-disalicyloylhydrazine (H2L) has the normal tendency to form both dimeric and tetrameric complexes coordinated through the dianionic tridentate manner. Chapter 5: Two novel dioxomolybbdenum(VI) complexes containing the MoO22+ motif are reported where unexpected coordination due to ligand rearrangement through metal mediated interligand C–C bond formation is observed. The ligand transformations are probably initiated by molybdenum assisted C–C bond formation in the reaction medium. The ligands (H2L1–2) are tetradentate C–C coupled O2N2– donor systems formed in situ during the synthesis of the complexes by the reaction of bis(acetylacetonato)dioxomolybdenum(VI) with Schiff base ligands of 2-aminophenol with 2-pyridine carboxaldehyde (HL1) and 2-quinolinecarboxaldehyde (HL2). The reported dioxomolybdenum(VI) complexes [MoO2L1] (1) and [MoO2L2] (2) coordinated with the O2N2– donor rearranged ligand are expected to have better stability of the molybdenum in +6 oxidation state than the corresponding ON2–donor ligand precursor. Both the complexes are fully characterized by several physicochemical techniques and the novel structural features through single crystal X-ray crystallography. vii Chapter 6: In this chapter we present a detailed account of the synthesis, structure, spectroscopic, electrochemical properties and study of biological activity of some oxomolybdenum(VI) complexes with special reference to their H–bonded molecular and supramolecular structures. Reaction of bis(acetylacetonato)dioxomolybdenum(VI) with three different hydrazides (isonicotinoyl hydrazide, anthraniloyl hydrazide and 4-nitrobenzoyl hydrazide) afforded two di-oxomolybdenum(VI) complexes {[MoO2L1(CH3OH)] (1) and [MoO2L3] (3)} and one mono-oxomolybdenum(VI) complex {[MoOL2(O–N)] (2)} (where L = Intermediate in situ ligand formed by the reaction between acetyl acetone and the corresponding acid hydrazide, and O–N = 4-nitrobenzoylhydrazide). All the complexes have been characterized by elemental analysis, electrochemical and spectroscopic (IR, UV–Vis and NMR) measurements. Molecular structures of all the complexes (1, 2 and 3) have been determined by X-ray crystallography. The complexes have been screened for their antibacterial activity against Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. The Minimum inhibitory concentration of these complexes and antibacterial activity indicates 1 as the potential lead molecule for drug designing

Investigation of DNA interaction and antiproliferative activity of mixed ligand dioxidomolybdenum(VI) complexes incorporating ONO donor aroylhydrazone ligands

Four new mixed ligand dioxidomolybdenum(VI) [MoVIO2L1-3(Q)] (1–3), [MoVIO2L4(Q)]2 (H2O) (4) [where Q = MeOH for 1 and imidazole for 2–4] complexes have been synthesized using four different ONO donor aroylhydrazone ligands (H2L1–4). All the derived ligands and complexes have been characterised by different physicochemical techniques, that is, elemental analysis, spectroscopic methods (UV–Vis, NMR and IR), and cyclic voltammetry. The molecular geometries of 1–4 were established by X-ray crystallography which reveals - - the Schiff base ligands coordinate - the distorted octahedral metal centres in a di-negative tridentate fashion. The complexes have shown moderate binding affinity (103 to 104 M−1) towards CT-DNA. Further, in vitro cytotoxicity activity of all the complexes were determined against HT-29 (colon cancer) and HeLa (cervical cancer) cell lines. Complex 4, due to the presence of a heterocyclic 2-hydroxy-1-naphthyl moiety in the ligand backbone, was found to be more biologically active in comparison to the others in the series

A study of DNA/BSA interaction and catalytic potential of oxidovanadium(V) complexes with ONO donor ligands

The study of DNA/BSA interaction and the catalytic potential of four mononuclear oxidoalkoxido vanadium(V) [VVO(L¹⁻⁴)OEt] (1–4) and one dinuclear oxidoalkoxido mixed-ligand vanadium(V) [{VO(L²)OEt} ₂ (Q)]{Q = 4,4′-bipyridine}(5) complexes, with tridentate binegative aroylazine ligands are reported [where H₂L¹ = anthranylhydrazone of 2- hydroxy-1- napthaldehyde, H₂L² = salicylhydrazone of 2-hydroxy-1- napthaldehyde, H₂L³ = benzoylhydrazone of 2-hydroxy-1- acetonaphthone, H₂L⁴ = anthranylhydrazone of 2-hydroxy-1- acetonaphthone]. All the complexes are characterized by elemental analysis as well as various spectroscopic techniques. Single crystal X-ray diffraction crystallography of 2 reveals that the metal centre is in distorted square pyramidal geometry with O₄N coordination spheres, whereas 5 exhibits a distorted octahedral geometry around the metal center. In addition, all the complexes (1–5) show moderate DNA binding propensity which is investigated using UV-vis absorption titration, circular dichroism, thermal denaturation and fluorescence spectral studies. The experimental results show that the complexes effectively interact with CT-DNA through both minor and major groove binding modes, with binding constants ranging from 10⁴ −10⁵ M⁻¹. Among 1–5, complexes 3 and 4 show higher binding affinity towards CT-DNA than others and at the same time also exhibit negative ΔTm values of about ∼1.5 and 1.0 °C which resembles the properties shown by cisplatin. All complexes show moderate photo-induced cleavage of pUC19 supercoiled plasmid DNA with complex 3 showing the highest photo induced DNA cleavage activity of ∼48%. In coherence with the DNA interaction studies, 3 and 4 also exhibit good binding affinity towards BSA in the range of 10¹⁰ −10¹¹ M⁻¹, which is also supported by their ability to quench the tryptophan fluorescence emission spectra of BSA. All the complexes show remarkable photo-induced BSA cleavage activity (>90%) at a complex concentration of 50 μM. The catalytic potential of 1–5 is also tested for the oxidative bromination of styrene, salicylaldehyde and oxidation of methyl phenyl sulphide. All the reactions show a high percentage of conversion (>90%) with a high turnover frequency (TOF). Particularly, in the oxidative bromination of styrene the percentage of conversion and TOF vary from 96–98% and 8000–19 600 (h⁻¹) respectively, which signifies the potential of these oxidovanadium(V) complexes to stimulate research for the synthesis of a better catalyst

Monomeric and dimeric oxidomolybdenum(V and VI) complexes, cytotoxicity, and DNA interaction studies: molybdenum assisted C═N bond cleavage of salophen ligands

Four novel dimeric bis-μ-imido bridged metal–metal bonded oxidomolybdenum(V) complexes [MoV2O2L′21–4] (1–4) (where L′1–4 are rearranged ligands formed in situ from H2L1–4) and a new mononuclear dioxidomolybdenum(VI) complex [MoVIO2L5] (5) synthesized from salen type N2O2 ligands are reported. This rare series of imido- bridged complexes (1–4) have been furnished from rearranged H3L′1–4 ligands, containing an aromatic diimine (o-phenylenediamine) “linker”, where Mo assisted hydrolysis followed by −C═N bond cleavage of one of the arms of the ligand H2L1–4 took place. A monomeric molybdenum(V) intermediate species [MoVO(HL′1–4)(OEt)] (Id1–4) was generated in situ. The concomitant deprotonation and dimerization of two molybdenum(V) intermediate species (Id1–4) ultimately resulted in the formation of a bis-μ-imido bridge between the two molybdenum centers of [MoV2O2L′21–4] (1–4). The mechanism of formation of 1–4 has been discussed, and one of the rare intermediate monomeric molybdenum(V) species Id4 has been isolated in the solid state and characterized. The monomeric dioxidomolybdenum(VI) complex [MoVIO2L5] (5) was prepared from the ligand H2L5 where the aromatic “linker” was replaced by an aliphatic diimine (1,2-diaminopropane). All the ligands and complexes have been characterized by elemental analysis, IR, UV–vis spectroscopy, NMR, ESI- MS, and cyclic voltammetry, and the structural features of 1, 2, 4, and 5 have been solved by X-ray crystallography. The DNA binding and cleavage activity of 1–5 have been explored. The complexes interact with CT-DNA by the groove binding mode, and the binding constants range between 103 and 104 M–1. Fairly good photoinduced cleavage of pUC19 supercoiled plasmid DNA was exhibited by all the complexes, with 4 showing the most promising photoinduced DNA cleavage activity of ∼93%. Moreover, in vitro cytotoxic activity of all the complexes was evaluated by MTT assay, which reveals that the complexes induce cell death in MCF-7 (human breast adenocarcinoma) and HCT-15 (colon cancer) cell lines

Synthesis, structural studies and catalytic activity of dioxidomolybdenum(VI) complexes with aroylhydrazones of naphthol-derivative

Reaction of the salicylhydrazone of 2-hydroxy-1-naphthaldehyde (H2L1), anthranylhydrazone of 2hydroxy-l-naphthaldehyde (H2L2), benzoylhydrazone of 2-hydroxy-1-acetonaphthone (H2L3) and anthranylhydrazone of 2-hydroxy-1-acetonaphthone (H2L4; general abbreviation H2L) with MoO2(acac)21 afforded a series of 5- and 6- coordinate Mo(VI) complexes of the type MoO2L1-2(ROH)] where R = C2H5 (1) and CH3 (2)], and MoO2L3-4] (3 and 4). The substrate binding capacity of 1 has been demonstrated by the formation of one mononuclear mixed-ligand dioxidomolybdenum complex MoO2L1(Q)] (where Q= gamma-picoline (la)). Molecular structure of all the complexes (I, la, 2,3 and 4) is determined by X-ray crystallography, demonstrating the dibasic tridentate behavior of ligands. All the complexes show two irreversible reductive responses within the potential window -0.73 to -1.08 V, due to Movl/Mov and Mov/Mow processes. Catalytic potential of these complexes was tested for the oxidation of benzoin using 30% aqueous H2O2 as an oxidant in methanol. At least four reaction products, benzoic acid, benzaldehydedimethylacetal, methyl benzoate and benzil were obtained with the 95-99% conversion under optimized reaction conditions. Oxidative bromination of salicylaldehyde, a functional mimic of haloperoxidases, in aqueous 1-1202/KEr in the presence of HC1O4 at room temperature has also been carried out successfully. (C) 2013 Elsevier Ltd. All rights reserved

Mixed-ligand aroylhydrazone complexes of molybdenum: Synthesis, structure and biological activity

The reaction of the benzoylhydrazone of 2-hydroxybenzaldehyde (H2L) with MoO2(acac)(2)] proceeds smoothly in refluxing ethanol to afford an orange complex MoO2L(C2H5OH)] (1). The substrate binding capacity of 1 has been demonstrated by the formation and isolation of two mononuclear MoO2L(Q)] {where Q = imidazole (2a) and 1-methylimidazole (2b)} and one dinuclear (MoO2L)(2)(Q)] {Q = 4,4'-bipyridine (3)} mixed-ligand oxomolybdenum complex. All the complexes have been characterized by elemental analysis, magnetic and spectroscopic (IR, UV-Vis and NMR) measurements. The molecular structures of all the oxomolybdenum(VI) complexes (1, 2a, 2b and 3) have been determined by X-ray crystallography. In each complex, the dianionic planar ligand is coordinated to the metal centre via one enolate oxygen, one phenolate oxygen and an azomethine nitrogen atom. The complexes have been screened for their antibacterial activity against Escherichia coli, Bacillus and Pseudomonas aeruginosa. The minimum inhibitory concentration of these complexes and their antibacterial activity indicates that compounds 2a and 2b are potential lead molecules for drug designing. (C) 2012 Elsevier Ltd. All rights reserved

Syntheses and structural investigation of some alkali metal ion-mediated (LVO2-)-O-V (L2- = tridentate ONO ligands) species: DNA binding, photoinduced DNA cleavage and cytotoxic activities

Eight alkali metal ion-mediated dioxidovanadium(V), {(VO2L1-6)-O-V} A(H2O)n]proportional to, complexes for A = Li+, Na+, K+ and Cs+, containing tridentate aroylhydrazonate ligands coordinating via ONO donor atoms, are described. All the synthesised ligands and the metal complexes were successfully characterised by elemental analysis, IR, UV-Vis and NMR spectroscopy. X-ray crystallographic investigation of 3, 5-7 shows the presence of distorted NO4 coordination geometries for LVO2- in each case, and varying mu-oxido and/ or mu-aqua bridging with interesting variations correlated with the size of the alkali metal ions: with small Li+, no bridging-O is found but four ion aggregates are found with Na+, chains for K+ and finally, layers for Cs+. Two (5) or three-dimensional (3, 6 and 7) architectures are consolidated by hydrogen bonding. The dioxidovanadium(V) complexes were found to exhibit DNA binding activity due to their interaction with CT-DNA by the groove binding mode, with binding constants ranging from 10(3) to 10(4) M-1. Complexes 1-8 were also tested for DNA nuclease activity against pUC19 plasmid DNA which showed that 6 and 7 had the best DNA binding and photonuclease activity; these results support their good protein binding and cleavage activity with binding constants ranging from 104 to 105 M-1. Finally, the in vitro antiproliferative activity of all complexes was assayed against the HeLa cell line. Some of the complexes (2, 5, 6 and 7) show considerable activity compared to commonly used chemotherapeutic drugs. The variation in cytotoxicity of the complexes is influenced by the various functional groups attached to the aroylhydrazone derivative

Highly Stable Hexacoordinated Nonoxidovanadium(IV) Complexes of Sterically Constrained Ligands: Syntheses, Structure, and Study of Antiproliferative and Insulin Mimetic Activity

Three highly stable, hexacoordinated nonoxidovanadium(IV), V-IV(L)(2), complexes (1-3) have been isolated and structurally characterized with tridentate aroylhydrazonates containing ONO donor atoms. All the complexes are stable in the open air in the solid state as well as in solution, a phenomenon rarely observed in nonoxidovanadium(IV) complexes. The complexes have good solubility in organic solvents, permitting electrochemical and various spectroscopic investigations. The existence of nonoxidovanadium(IV) complexes was confirmed by elemental analysis, ESI mass spectroscopy, cyclic voltammetry, EPR, and magnetic susceptibility measurements. X-ray crystallography showed the N3O3 donor set to define a trigonal prismatic geometry in each case. All the complexes show in vitro insulin mimetic activity against insulin responsive L6 myoblast cells, with complex 3 being the most potent, which is comparable to insulin at the complex concentration of 4 mu M, while the others have moderate insulin mimetic activity. In addition, the in vitro antiproliferative activity of complexes 1-3 against the He La cell line was assayed. The cytotoxicity of the complexes is affected by the various functional groups attached to the bezoylhydrazone derivative and 2 showed considerable antiproliferative activity compared to the most commonly used chemotherapeutic drugs