Bruce D. James

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.

Five-coordinate triphenyltin(IV)-sulfur compounds. Crystal structures of the aminoethanethiol and 2-mercaptopyridine-N-oxide derivatives

Abstract Single crystal X-ray structure determinations have been carried out on Ph3SnS(CH2)2NH 2 (1) and Ph3SnSC5H4NO (2), and have shown that both compounds possess five- coordinate cis-chelate structures with SnS bonds.

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.

Some triphenyltin(IV) complexes containing potentially bidentate, biologically active anionic groups

Abstract Triphenyltin(IV) derivatives have been synthesized which contain anions from various biologically active acids. The coordination about the tin atom was investigated by infrared, 119 Sn NMR and Mossbauer spectroscopic methods. The triphenyltin cation with S-bonding groups generally acquires a four-coordinated structure. On the other hand, combination with O-bonding groups can produce several structural possibilities: four-coordinate, five-coordinate cis- and trans -trigonal bipyramidal and bridging carboxylate examples being obtained. Some of the higher coordination number species appear to dissociate in solution.

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.

Comparative stereochemical studies of Ph3SnL complexes (L=1-carbodithioato vs. 1-carbothioato ligand). Crystal structures of [Ph3Sn(S•CS•N(CH2)5] and [Ph3Sn(S•CO•N(CH2)4O)]

Single crystal X-ray structure determinations have been carried out on [Ph3Sn(S.CS.N(CH2)5)] (1) and [Ph3Sn(S.CO.N(CH2)4O)] (2) (the latter the first organotin(IV) complex of the monothiocarbamate ligand) and the results compared with those recently reported for [PH3Sn(S.CS.N(CH2)4)] (3) in order to throw light on details of the variations in the Sn environment and their possible causes. The crystal of compounds 1 and 2 are monoclinic, P21/c, Z = 4. For 1 a 10.009(5), b 15.959(7), c 15.831(6) A, β 115.79(3)°; R was 0.026 for No = 2224 ‘observed’ reflections. For 2, a 15.16(1), b 9.560(7), c 18.47(2) A, β 125.05(5)°; R = 0.031 for No = 2642. The overall molecular structures are similar, and similar to those of 3, with wide but parallel variations in CSnC (≈ 102–120°) and SSnC angles (≈91–120°). In 1 the SnS bond lengths are 2.481(2), 2.919(2) A, while in 2 the SnS,O bond lenghts are 2.446(2), 2.809(4) A, the longer distances in each case being associated with considerable double bond character in the adjacent CS,O linkage (1.678(4), 1.243(6) A).

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.

Fungicidal activity of some organotin compounds against ceratocystis ulmi

Three series of organotin compounds were screened in vitro against Ceratocystis ulmi, the causative agent of Dutch elm disease. The series that were most active against this deadly fungus were those that contained the triphenyltin moiety. In addition, the fungicidal activity of the triphenyltin compounds were found to be independent of the anionic group attached to the tin atom. However, there was a marked increase in the activity of the triphenyltins when a biologically active group which did not dissociate upon dissolution was incorporated into the overall molecule.