N. S. Neelam Jalil

Synthesis and Antifungal Activity of Some Organotin(IV) Carboxylates

Six diorganotin(IV) carboxylates prepared by reacting diorganotin(IV) dichlorides with the respective silver carboxylate have been tested for antifungal activity against Aspergillus. niger, Aspergilluus flavus and Pencillium. citrinum in Sabourand dextrose broth. The compounds generally exhibit greater fungitoxicity than the diorganotin(IV) dichlorides and the carboxylic acids from which they were synthesized. In keeping with the generally accepted notion that the organotin moiety plays an important role in deciding the antifungal activity of an organotin compound, the diphenyltin(IV) compounds were more active than their di-n-butyltin(IV) analogues. However, the order of increasing fungitoxicity of the compounds parallels that of the uncomplexed carboxylic acids. The implications of the results are discussed.

Complexes of Benzothiazole with Some Group IV Metal Halides

Abstract Complexes of benzothiazole (BT) of the composition SnX4 (BT) and MCl4(BT)2 (where X = Cl, Br or I; M = Ti, Zr or Si and BT = C7H5SN) have been prepared and studied by spectroscopic (proton magnetic resonance, electronic absorption and infrared spectra) techniques. The stability and composition of the complexes were established by melting point/decomposition point determinations and elemental analysis, respectively. Molar conductivity measurements show the covalent nature of the complexes. A polymeric structure involving ligand bridging through the sulphur and nitrogen atoms is suggested for the SnX4(BT) complexes. A trans-octahedral structure is suggested for the zirconium, silicon and titanium complexes with the ligands coordinated through the nitrogen atom.

SCHIFF BASE COMPLEXES OF SOME GROUP IV METAL HALIDES

Abstract Novel hexa-coordinated complexes of silicon(IV), titanium(IV), zirconium(IV) and tin(IV) chlorides of the general formula ML2Cl2 (where L = Schiff base prepared from the coupling reactions of glycine, leucine or cystine with O-hydroxyacetophenone), have been synthesized by refluxing the respective metal chloride and Schiff base in situ in an absolute ethanol and acetone mixture. The resulting complexes have been characterized by analytical data, spectroscopic (IR, UV, NMR) studies, melting points and conductance measurements. Chelate structures have been proposed for the complexes.

Complexes of Some Group IV Metal Halides with Glycine, Leucine and Cystine

Abstract The complexes of the composition MCl4.L2 and SnCl4.L (where M = Ti or Zr and L = glycine (gly), leucine (leu) or cystine (cys-scy)) have been synthesized by the interaction of these amino acids with the respective metal halides and were characterized by elemental analyses, melting point determinations, conductivity measurements and spectroscopic (UV, NMR and IR) analyses. The complexes were found to be quite stable to air, water and decomposition into their constituents at room temperature. The complexes behave as non-electrolytes in DMSO. The spectral data indicate that deprotonation of the zwitter ion of the amino acids occurs during the complex formation. The amino acids act as monodentate ligands in the TiCl4.L2 and ZrCl4.L2 complexes, coordinating through the amino nitrogen only. In the tin complexes, glycine and leucine behave as bidentate chelating agents, coordinating through both the amino nitrogen and carboxyl oxygen, while cystine bonds through the nitrogen atoms only. A trans-octahedr...

Complexes of Some Group IV Metal Halides, Acetate and Organotins with Thioacetamide

Abstract Reactions of silicon, tetrachloride, titanium tetrachloride, zirconium tetrachloride, tin tetrachloride, trimethyltin chloride, dibutyltin diacetate and tributyltin chloride with thioacetamide led to the formation of non-ionic and stable complexes of the formula MCl4. (TA)2 and SnX4. (TA)2 (where M = Si, Ti, Zr or Sn and X = Cl and CH3, CH3COO and C4H9 or C4H9 and Cl, and TA = thioacetamide). These complexes were characterized by melting/decomposition point determinations, analytical data, conductivity measurements and spectroscopic (UV and IR) studies. An octahedral geometry is proposed for all the complexes and coordination through sulphur is predicted. Referee I: A. J. Jircitano Referee II: R. F. Wilson

Complexes of Some Group IV Metal Tetrahalides and Organotins with Barbituric Acid

Abstract The synthesis and characterization of Si(IV), Ti(IV), Zr(IV), Sn(IV) halides, methyltin trichloride and dibutyltin diacetate complexes of barbituric acid are described. The complexes were characterized on the basis of elemental analyses as MX4.L2 (M = Si, Ti or Zr and × = Cl; M = Sn, × = Cl, Br, I, CH3 and Cl or CH3COO and C4H9, L = C4H4N2O3). The complexes are non-ionic and quite stable as indicated from their conductivity and melting points measurements, respectively. On the basis of spectral (IR and NMR) studies, coordination occurs through one of the carbonyl oxygens and an octahedral geometry is proposed for the complexes.

SOME ASPECTS OF THE COMPLEXES OF SILICON(IV), TITANIUM(IV), ZIRCONIUM(IV), TIN(IV), AND ORGANOTINS WITH 2-METHYLTHIAZOLINE

Abstract Silicon(IV), titanium(IV), zirconium(IV) and tin(IV) chlorides, methyltin trichloride, dibutyltin diacetate and tributyltin chloride complexes of the type MX2 (MTz)2 (where M = Si, Ti or Zr. and X = Cl; or M = Sn and X = Cl, CI and CH3, CH3COO and C4H9 or C4H9, and Cl. and MTz = 2-methylthiazoline) have been prepared by the reactions of respective metal salt and ligand in acetone medium and extracting the complex from the reaction mixture using petroleum ether. The stability and the composition of the complexes were established on the basis of melting point determinations and elemental analyses, respectively. Molar conductances of the complexes showed them to be covalent in nature. Bonding of ligand, MTz, to metal ion was suggested through nitrogen on the basis of spectral (IR, NMR, UV) studies. An octahedral geometry is proposed for the complexes.

Preparation and Spectrochemical Properties of N,N-Dimethylammonium Dimethyldithiocarbamate and N,N-Diethylammonium Diethyldithiocarbamate Complexes with Some Group(IV) Metal Halides

Abstract The complexes of the composition SnX2(S2CNR2)2, SiCl2(S2CNR2)2 and MCl3(S2CNR2) (where X = Cl, Br or I; R = methyl or ethyl and M = Ti or Zr) have been prepared by reaction of N,N-dialkyldithio-carbamates with respective metal halides. The stabilities and compositions of the complexes were established on the basis of melting point/decomposition point determinations and elemental analysis, respectively. Molar conductivity studies were carried out which suggest the covalent nature of the complexes. Spectrosco-pic (infrared, proton magnetic resonance and electronic absorption spectra) measurements suggest chelation of the dithiocarbamato moiety in all the complexes. A trans-octahedral geometry is predicted for tin and silicon complexes, whereas a polymeric structure involving halogen bridging is proposed for zirconium and titanium complexes.

TRIMETHYLTIN CHLORIDE AND PSEUDOHALIDE COMPLEXES OF TRYPTOPHAN

Abstract Organotin chloride and pseudohalide complexes of tryptophan of the type Me3SnX. Tryp (Me = methyl, X = Cl, SCN, N3, CN and NCO; Tryp = tryptophan) were prepared by the addition reactions of tryptophan with trimethyltin chloride and the appropriate pseudohalide prepared in situ. The complexes were characterized by elemental analyses, spectroscopic (IR, NMR) studies, melting point and conductance measurements. Melting point and conductance measurements show them to be stable and non-electrolytes in DMSO. The spectroscopic data indicate that tryptophan coordinates with tin covalently through its carboxylate group as an asymmetric bidentate ligand. It is suggested that the complexes have an octahedral geometry.

Synthetic and Some Spectral Aspects of the Complexes of Mono, Di and Triorganotins with Benzothiazole and Piperazine-1,4-dicarbodithioate

Abstract Non-ionic complexes of the composition CH3SnCl.-C6H8N2S4, CH3SnCl3.(C7H5SN)2, (C4H9)2Sn.C6H8N2S4, (C4H9)2Sn(CH3COO)2.C7H5SN and (C4H9)3SnCl.C7H5SN have been synthesized by the reactions of methyltin trichloride, dibutyltin diacetate and tributyltin chloride with benzothiazole and the sodium salt of piperazine-1,4-dicarbodithioate (Na2C6H8N2S4) in dry acetone solutions. Some spectral (NMR, IR and UV) properties of these complexes have also been studied.