Farha Firdaus

TEMPLATE SYNTHESIS OF IRON(II), COBALT(II), COPPER(II) AND ZINC(II) COMPLEXES OF DIAMIDEDIIMINE MACROCYCLES

A series of iron(II), cobalt(II), copper(II) and zinc(II) complexes containing tetraazamacrocyclic ligands have been prepared by the condensation of 1,2-diaminoethane, 1,3-diaminopropane and ortho-phenylene diamine with methyl acetoacetate or ethyl acetoacetate in the presence of iron(II), cobalt(II), copper(II) and zinc(II) salts at room temperature. The structure and bonding of macrocyclic ligands have been studied from elemental analysis, magnetic susceptibility measurements, IR, 1H NMR, mass, EPR and electronic spectra of the complexes. The stereochemistry around the metal ions is octahedral in which four of the coordination sites are occupied by the nitrogens of the macrocyclic ligand and the remaining octahedral positions are occupied by two chlorines.

Template synthesis and spectroscopic characterization of 16-membered [N4] Schiff-base macrocyclic complexes of Co(II), Ni(II), Cu(II), and Zn(II): in vitro DNA-binding studies

Template condensation between o-phthalaldehyde and 3,4-diaminotoluene resulted in mononuclear 16-membered tetraimine macrocyclic complexes, [MLCl2] [M = Co(II), Ni(II), Cu(II), and Zn(II)]. The proposed stoichiometry and the nature of the complexes have been deduced from elemental analyses, mass spectra, and molar conductance data. The macrocyclic framework has been inferred from ν(C=N) and ν(M–N) bands in the IR spectra and the resonances observed in 1H and 13C-NMR spectra. Octahedral geometry has been assigned for all these complexes on the basis of position of the bands in electronic spectra and magnetic moment data; distorted octahedral geometry has been assigned for the Cu(II) complex on the basis of EPR data. The low-conductivity data of all the complexes suggest their non-ionic nature. Interaction of these complexes with calf-thymus DNA (CT DNA) has been examined with fluorescence quenching experiments, which show that the complexes are avid binders of CT DNA.

Template synthesis and physico-chemical characterization of 14-membered tetraimine macrocyclic complexes, [MLX2] [M=Co(II), Ni(II), Cu(II) and Zn(II)]. DNA binding study on [CoLCl2] complex

The template condensation reaction between glyoxal and 1,8-diaminonaphthalene resulted a few novel mononuclear 14-membered tetraimine macrocyclic complexes of the type, [MLX(2)] [M=Co(II), Ni(II), Cu(II) and Zn(II), for X=Cl or NO(3)]. The stoichiometry and the nature of the complexes have been deduced from the results of elemental analyses and conductance data. The formation of macrocyclic framework has been inferred from the appearance of imine upsilon(CN) and upsilon(MN) band in IR spectra and the resonance signals observed in (1)H and (13)C-NMR spectra. However, the overall geometry of the complexes has been assigned on the positions of bands in electronic spectra and magnetic moment data. The distortion in Cu(II) complexes has been deduced on EPR data. The thermal behavior of these complexes has been studied by TGA analysis. Absorption and circular dichroism studies on the complex proved a significant binding to calf thymus DNA.

Synthesis, spectroscopic characterization, DNA interaction and antibacterial study of metal complexes of tetraazamacrocyclic Schiff base

The template condensation reaction between benzil and 3,4-diaminotoulene resulted mononuclear 12-membered tetraimine macrocyclic complexes of the type, [MLCl(2)] [M=Co(II), Ni(II), Cu(II) and Zn(II)]. The synthesized complexes have been characterized on the basis of the results of elemental analysis, molar conductance, magnetic susceptibility measurements and spectroscopic studies viz. FT-IR, (1)H and (13)C NMR, FAB mass, UV-vis and EPR. An octahedral geometry has been envisaged for all these complexes, while a distorted octahedral geometry has been noticed for Cu(II) complex. Low conductivity data of all these complexes suggest their non-ionic nature. The interactive studies of these complexes with calf thymus DNA showed that the complexes are avid binders of calf thymus DNA. The in vitro antibacterial studies of these complexes screened against pathogenic bacteria proved them as growth inhibiting agents.

Interaction mode of polycarbazole–titanium dioxide nanocomposite with DNA: Molecular docking simulation and in-vitro antimicrobial study

A polycarbazole-titanium dioxide (PCz/TiO2-8) nanocomposite was synthesized for the first time by in-situ oxidative polymerization with APS as an oxidizing agent in the presence of TiO2 nanoparticles which was characterized by SEM, TEM, FT-IR, DTA and TGA techniques. The SEM and TEM results showed that PCz has polymerized on the surface of the TiO2. The results confirmed the incorporation of TiO2 in PCz indicating the formation of nanocomposite due to strong interaction between TiO2 and PCz matrix affecting the properties as compared to pristine PCz. The PCz/TiO2-8 nanocomposite was tested for antimicrobial activity and found to exhibit activity against gram negative and gram positive strains at micromolar concentrations. The four types of 3D molecular field descriptors or field points as extrema of electrostatic, steric, and hydrophobic fields were explained. These field points were used to define the properties necessary for a molecule to bind in a characteristic way into a specified active site. A molecular docking simulation was used to predict the modes of interactions of the drugs (PCz and PCz/TiO2-8) with DNA. The molecular docking conclusion indicated that the modes of interactions between two (PCz and PCz/TiO2-8) and DNA helix can be regarded as minor groove binder. The K value (3.55 × 10(4) M(-1) and 2.13 × 10(5) M(-1)) obtained from fluorescence data are indicative of binding of PCz and PCz/TiO2-8 with DNA helix.

Synthesis, spectroscopic, thermal, and antimicrobial studies of tetradentate 12 and 14 member Schiff bases and their complexes with Fe(III), Co(II), and Cu(II)

Two Schiff bases, L1 (5,6;11,12-dibenzophenone-2,3,8,9-tetramethyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene) and L2 (6,7;13,14-dibenzophenone-2,4,9,11-tetramethyl-1,5,8,12-tetraazacyclotetradeca-1,4,8,11-tetraene), bearing functionalized pendant arms have been synthesized by cyclocondensation of 3,4-diaminobenzophenone with 2,3-butanedione and 2,4-pentanedione, respectively. Mononuclear macrocyclic complexes [FeL1Cl2]Cl, [FeL2Cl2]Cl, [ML1Cl2], and [ML2Cl2] (where M = Co(II) and Cu(II)) have been prepared by reacting iron(III), cobalt(II), and copper(II) with the preformed Schiff base. The ligands and their corresponding metal complexes were characterized by elemental analyses, ESI-mass spectra, conductivity, magnetic moments, UV-Vis, EPR, IR, 1H-, and 13C-NMR spectral studies, and TGA-DTA/DSC data. The TGA profiles exhibit a two-step pyrolysis, although the iron complexes decompose in three steps, leaving behind metal oxides as the final product. The ligands and complexes were screened in vitro against Gram-positive bacteria, Gram-negative bacteria, and fungi.

Organotellurium(IV) derivatives: Synthesis and characterization of metal dialkyltetrakis(chlorosulphato)tellurate(IV), M2[R2Te(SO3Cl)4] (M Na, K) and Sn[R2Te(SO3Cl)4] (R CH3, C2H5, n-C3H7, n-C4H9

Abstract The ability of R2Te(SO3Cl)2 (R  CH3, C2H5, n-C3H7, n-C4H9) compounds to behave as a SO3Cl− acceptors has been proved by the synthesis and characterization of new monomeric complexes of the type M2[R2Te(SO3Cl)4] (M Na, K) and Sn[R2Te(SO3Cl)4] by reacting stoichiometric amounts of R2TeI2 (R  CH3, C2H5, n-C3H7, n-C4H9) with metal salts, namely NaI, KI and SnCl2, in excess HSO3Cl. The compounds are hygroscopic in nature but are stable under dry nitrogen. The IR spectra of the compounds suggest that the SO3Cl− is covalently bonded to the dialkyltellurium moiety. The observed molar conductance values of these compounds in DMSO confirm that they are 1:1 and 1:2 electrolytes. The 1H NMR spectra are discussed in terms of inductive effects and since the chlorosulphate group is expected to be bound in monodentate manner the hexacoordination around the tellurium atom is maintained.

Synthesis and Characterization of Metal Mono (Chlorosulphates) M(SO3CL) [M = Ag(I) and Hg(I)] and Their Complexes with Organic Donor Bases

Abstract The solvolytic reaction of silver(I) acetate and mercury(I) chloride in chlorosulphuric acid afforded Ag(SO3Cl) and Hg2(SO3Cl)2, respectively, where HSO3Cl acts both as medium of reaction as well as chlorosulphonating agent. These compounds are hygroscopic in nature and dissolve in non-polar solvents. The coordinating ability of the SO3Cl− group has been further investigated by synthesizing the complexes of these metal monochlorosul phates with strong donor organic bases leading to the formation of complexes of the types [M(SO3Cl)L3] [L = triphenylphosphine, pyridine, pyridine N-oxide] and [M(SO3Cl)L] [L = 2,2′-bipyridine, acridine]. The SO3Cl− group has been found to be covalently bonded to the metal ions or the complex cations [MLn]+ as evidenced by the shift to higher frequency of ν1(A), splitting of doubly degenerate (E) modes and low values of electrical conductivities. The magnetic moment measurements indicate their diamagnetic nature. Referee I: J. A. Heppert Referee II: G. C. Defotis

Synthesis, Spectroscopic Characterization, and In Vitro Antimicrobial Screening of 16-Membered Tetraazamacrocyclic Schiff-Base Ligand and its Complexes with Co(II), Ni(II), Cu(II), and Zn(II) Ions

A 16-membered tetraazamacrocyclic ligand has been synthesized by condensation reaction of 2-methyl acetoacetanilide with 1,8-diaminonaphthalene, and the metal complexes of the type [MLCl2] [M = Co(II), Ni(II), Cu(II), Zn(II)] were prepared by interaction of the ligand with metal salts. The ligand and its complexes were characterized by various spectroscopic studies. The mode of bonding and the overall geometry of these complexes have been deduced by elemental analysis, molar conductance values, Fourier-transform infrared (FT-IR), 1H-nuclear magnetic resonance (NMR), fast-atom bombardment (FAB) mass, electron paramagnetic resonance (EPR), and ultraviolet–visible (UV-VIS) spectroscopy along with magnetic measurement studies. An octahedral geometry has been envisaged for all these complexes, while a distorted octahedral geometry has been noticed for the Cu(II) complex. The cyclic voltammograme of the Cu(II) complex exhibits a quasi-reversible one-electron transfer wave for the Cu(II)/Cu(I) couple. The low conductivity data of all the complexes suggest their nonionic nature. These complexes have also been screened against pathogenic bacteria and fungi in vitro as growth-inhibiting agents.

Solvolysis in chlorosulphonic acid: preparation and characterization of K[Hg(SO3Cl) n I3- n ], (NH4)2[Zn(SO3Cl) n Cl4- n ], UO2[Zn-(SO3Cl) n (OAc)4- n ], K3[Cr(SO3Cl)6], K3[Cr(SO3Cl)2(C2O4)2], K3[Cr(SO3Cl)4(C2O4)] and Na3[Co(SO3Cl) n (ONO)6 - n ] (n = 1, 2, 3, 4, 5)

SummaryThe solvolytic reaction of anhydrous K[HgI3], (NH4)2-[ZnCl4], UO2[Zn(OAc)4], K3[Cr(C2O4)3] and Na3[Co-(ONO)6] in an excess of chlorosulphonic acid resulted in the formation of K[Hg(SO3Cl)3], (NH4)2[Zn(SO3Cl)4], UO2[Zn(SO3Cl)4], K3[Cr(SO3Cl)6] and Na3[Co(SO3Cl)6], respectively. Reactions with stoichiometric amounts of HSO3Cl, i.e. 1∶1 and 1∶2 molar ratios for K[HgI3], 1∶1, 1∶2 and 1∶3 for (NH4)2[ZnCl4] and UO2[Zn(OAc)4], 1∶2 and 1∶4 for K3[Cr(C2O4)3] and 1∶1, 1∶2, 1∶3, 1∶4, 1∶5 for Na3[Co(ONO)6] afforded compounds K[Hg(SO3Cl)nI3-n], (NH4)2[Zn(SO3Cl)nCl4-n], UO2[Zn(SO3Cl)n(OAc)4-n], K3[Cr(SO3Cl)2(C2O4)2], K3[Cr(SO3Cl)4(C2O4)] and Na3[Co(SO3Cl)n(ONO)6-n] (n = 1,2,3,4,5). The compounds are hygroscopic but are stable under an N2 atmosphere. The i.r. spectra suggest that SO3Cl− is covalently bound in the complex anions, and the high electrical conductivities confirm the ionic nature of the compounds. The magnetic moments and electronic spectra suggest that each SO3Cl− group is monodentate, giving either tetrahedral or octahedral geometry around the metal ions.