G. Domazetis

Organotin (IV) derivatives of L-cysteine and DL-penicillamine

Abstract The preparations of chlorodimethyl- and chlorodi-η-butyl tin(IV) derivative of L-cysteine, L-cysteine ethyl ester and DL-pencillamine are described. Infrared, n.m.r. and mass spectral data are presented. The compounds contain SnS bonds and suggestions for structures are made.

C13 N.M.R. spectroscopy on butyltin compounds containing N-, O- and S- ligands.

Abstract 13 C NMR data are reported for a range of tributyl and dibutyl-tin complexes containing O, N and S ligands. The coupling constant J 1 appears to be indicative of the coordination state of the tin atom. Using J 1 , shift values and other supporting evidence, structure for a number of the compounds are proposed.

Tri-n-butyltin(IV) derivatives of L-cysteine ethyl ester, N-acetyl-L cysteine and α-glutamyl cysteinyl glycine (glutathione reduced)

Abstract Syntheses and spectroscopic data ( 1 H and 13 C N.M.R., I.R. and Mossbauer) are presented for L-cysteine ethyl ester, N-acetyl L-cysteine and Glutathione (reduced) tri- n -butyl tin derivatives. The L-cysteine ethyl ester compound appears to be four coordinate with a SnS bond while the N-acetyl L-cysteine complex contains a four coordinate ( n -C 4 H 9 ) 3 Sn-S moiety and a ( n -C 4 H 9 ) 3 SnOCO grouping containing chelating carboxylate. In moderately concentrated solutions, dimeric species exist with hyrogen bonding between NH and CO groups. The Glutathione complex is strongly associated, probably via N→Sn coordination. The ( n -C 4 H 9 ) 3 Sn entities in this complex are bonded to the cysteine and glycine residues.

Mössbauer spectra of organotin amino-acid and glutathione derivatives

Abstract Mossbauer parameters are reported for compounds in which organotin entities are bonded to thiolate, carboxylate and sulfonate groups of simple ligands (L-cysteine and derivatives, DL-penicillamine, cysteic acid and Glutathione reduced) which have biological relevance. The relationship between the stereochemistry about the tin atom and the corresponding quadropole splitting value is examined and the extension to the use of Mossbauer spectroscopy to determine the binding of organotins in more complex biochemical systems is discussed.

Bis (2-thio-5-nitropyridine)-S-di-n-butylstannane (IV): Crystal structure and spectroscopic studies

Abstract X-Ray analysis has defined the crystal structure of the title compound. The crystals are monoclinic and belong to the space group C2/c with cell dimensions, a = 21.731(8), b = 14.141(6), c = 7.648(5) A , β = 100.04(5) and Z = 4. The complex molecule has C2 symmetry; the S and C atoms bonded to the Sn form a distorted tetrahedral arrangement around the latter, with SnS and SnC bond distances of 2.477(3) and 2.162(11)A respectively. There is a short intramolecular contact between the Sn and N in the pyridine ring, of 2.77(1)A. IR and NMR spectral data have been interpreted on the basis of the X-ray structure; mass spectral data is predominantly influenced by strong tin-ligand bonding, reflecting a contribution by the Sn..... N interaction.

Synthesis and spectroscopic studies of organotin compounds containing the SnS bond

Abstract The preparation of a number of organotin(IV) compounds, containing SnS bonds, is described. Their 13C and 1H NMR and IR spectra are presented. In cases where either SnS or SnN may be expected, Mossbauer spectra show two sets of peaks consistent with these possibilities.

Synthesis and structure of some triphenyltin(IV) dithiocarbamate compounds

Abstract A low temperature synthesis is described for the preparation of organotin dithiocarbamate compounds (including N -cyclic and N -monosubstituted derivatives) in which the products have low levels of the usual sulfide impurities. IR spectra cannot differentiate unambiguously the bidentate and anisobidentate modes of bonding of the dithiocarbamate ligands with the metal, but 1 H NMR spectra of the (C 6 H 5 ) 3 Sn moiety exhibit ( o-mp ) shift differences which can, in part, be attributed to anisobidentate bonding. The effect of solvents on shift values is also indicative of this unsymmetric chelation.

Synthesis and spectroscopic studies of some organotin(IV) compounds containing the SnO bond

Abstract The preparation of a number of organotin(IV) compounds, containing SnO bonds, is described. Their 13 C and 1 H NMR, IR spectra, and some molecular weight determinations, are presented. Structures are postulated based largely on the one bond coupling constant 1 J ( 119 117 Sn  13 C ) . Further evidence is obtained from 1 H NMR and IR spectra. For the compounds reported, IR spectra do not appear to provide unambiguous evidence because of difficulties in assigning and interpreting CO, SnO and SnC stretch frequencies.

Reactions of triorganotin(IV) compounds with L-cysteine, L-cysteine ethyl ester, N-acetyl L-cysteine and glutathione reduced

Bis-[triphenylstannyl]-oxid reagiert mit L-Cystein bei 70°C in einer Wasser-EtOH-Mischung nur zu dem entsprechenden Sulfid, wahrend die Reaktion von L-Cysteinethylester mit Bis-[triphenyl(bzw. tributyl)stannyl]-oxid oder SnMe3Cl bei pH 8-11 im gleichen Losunsmittel die Verbindungen (I) liefert.

Variable-Temperature Tin-119m Moessbauer Study of the Chlorodimethyltin (IV) Derivatives of L-Cysteine and DL-Penicillamine.

Abstract : The question of intermolecular association in the chlorodimethyltin (IV) derivatives of L-cysteine (a monohydrate) and DL-penicillamine is settled by variable-temperature tin-119m Mossbauer data between 77 and 140 or 150k, respectively. The slopes of the natural logs of the areas under the resonance are -1.58 + or - 0.1/100/K and -1.46 + or - 0.1/100/K, respectively, considerably lower than those for monomeric lattices. These data rule out an extended association through bridging amino nitrogen atoms or carboxyate oxygen atoms, and suggest a lattice in which small molecular or oligomeric units are associated by an extensive network of hydrogen bonds. An alternative ionic structure of Cl(CH3)2SnSCR2CH(NH3(+))C00- units where R = H can be ruled out on the basis of infrared data (nu(OH)=3450/cm).