Review: Organotin compounds and their therapeutic potential: a report from the Organometallic Chemistry Department of the Free University of Brussels

Synthesis, Characterization, Biocide and Toxicological Activities of Di-n-butyl- and Diphenyl-tinIV-Salicyliden-β-Amino Alcohol Derivatives

The one pot reaction of salicylaldehyde 1, beta-amino alcohols 2a-2c, and di-n-butyltin(IV) oxide 3a or diphenyltin(IV) oxide 3b produced five diorganotin(IV) compounds, 4a-4c, 5a, and 5c, in good yields. All compounds were characterized by IR, (1)H, (13)C, and (119)Sn NMR spectroscopy, and elemental analysis; furthermore, compounds 4b, 4c, 5a, and 5c were characterized by X-ray diffraction analysis. After the structural characterization, all of the compounds were tested in vitro against Bacillus subtilis (Gram-positive, strain ATCC 6633), Escherichia coli (Gram-negative, strain DH5alpha), Pseudomonas aeruginosa (Gram-negative, strain BH3), Desulfovibrio longus (strain DSM 6739), and Desulfomicrobium aspheronum (strain DSM 5918) to assess their antimicrobial activity. Compounds 4 and 5 demonstrated a wide range of bactericidal activities against the tested aerobic (one Gram-positive and two Gram-negative subtypes) and anaerobic bacteria (two sulfate-reducing bacteria, SRB). Compound 5 had better bactericidal performances than compound 4. For all of the compounds, the acute toxicity was measured using luminescent bacteria toxicity (LBT-Microtox) tests to track their further environmental impact. According to these results and in order to fulfill environmental regulations, the toxicity of the compounds studied herein can be modulated through the proper selection of the disubstituted tin(IV) moiety.

The synthesis and characterisation of Sn(IV) complexes of 2,6-pyridine dicarboxylate--the molecular structure of divinyltin(IV) derivative

A series of organotin(IV) derivatives were obtained employing 2,6-pyridinedicarboxylate as ligand: [{SnBu3(OOC)2C5H3N}n] (1), [SnBuCl(OOC)2C5H3N] (2) and [Sn(CHCH2)2(OOC)2C5H3N] (3). They were fully characterised by multinuclear NMR [1H, 13C{1H}, and 119Sn{1H}], IR spectroscopies and elemental analysis. In addition suitable crystals of (3) have shown a dimmeric arrangement by X-ray crystallographic studies, held together by Sn-O intermolecular interactions which persists in solution. The crystal packing shows hydrogen bonds joining the dimmers, forming two infinite one-dimensional chain. Each monomer comprises a Sn(IV) centre bonded to a pyridinecarboxylate-containing ring, through both nitrogen and oxygen donor atoms. It is also co-ordinated by a water molecule and two vinyl groups.

New triorganotin(IV) derivatives of dipeptides as anti-inflammatory–antimicrobial agents

New triorganotin(IV) derivatives of dipeptides with general formulae R(3)Sn(HL), where R = Me and/or n-Bu and/or Ph and HL is the monoanion of glycylglycine (H(2)L-1), glycylvaline (H(2)L-2), glycylleucine (H(2)L-3), glycyltryptophane (H(2)L-4) and glycyltyrosine (H(2)L-5) have been synthesized and characterized on the basis of infrared, multinuclear NMR and (119)Sn Mossbauer spectroscopic studies. All the newly synthesized compounds were examined for their in vivo anti-inflammatory activity (using the carrageenan-induced paw edema bioassay in rats), acute toxicity (LD(50)) and cardiovascular activity. These compounds were also screened for their in vitro antimicrobial activity against Staphylococcus aureus Mau (29/58) and (78/71), Bacillus subtilis (18/64), Escherichia coli (326/71), Candida albicans (Pn-10), Microsporum gypseum and Euglena gracillis. The results revealed that triphenyltin(IV) derivatives exhibited anti-inflammatory activity comparable to that of phenylbutazone with high safety margin (LD(50) > 500 mg kg(-1)). Further Ph(3)Sn(Gly-Val) displays a potent cardiovascular activity. Moreover, most of the compounds displayed appreciable antibacterial activities when compared with ampicillin and norfloxacin. Compounds Ph(3)Sn(Gly-Gly) and Ph(3)Sn(Gly-Val) are the most distinctive derivatives identified in the present study because of their promising in vivo anti-inflammatory activity and in vitro antibacterial activity against gram-positive and -negative bacteria.

Synthesis, Characterization, and Hydrolytic Behavior of Mixed-Ligand Diorganotin Esters, [R2Sn(O2CR‘)OSO2Me]2 (R = n-Pr, n-Bu; R‘ = C9H6N-2, 4-OMe-C9H5N-2, C9H6N-1)

Reactions of the tin precursors, R2Sn(OMe)OSO2Me (R=n-Pr, n-Bu), with an equimolar quantity of 2-quinoline/4-methoxy-2-quinoline/1-isoquinoline carboxylic acid in acetonitrile proceed under mild conditions (rt,12-15 h) via selective Sn-OMe bond cleavage to afford the corresponding mixed-ligand diorganotin derivatives [R2Sn(O2CR')OSO2Me]2 [R'=C9H6N-2, R=n-Pr (1), n-Bu (2); R'=4-OMe-C9H5N-2, R=n-Pr (3), n-Bu (4); R'=C9H6N-1, R=n-Pr (5), n-Bu (6)]. These have been characterized by FAB mass, IR, and multinuclear (1H, 13C, 119Sn) NMR spectral data and X-ray crystallography (for 4 and 6). The molecular structure of 4 (C20H29NO6SSn, monoclinic, P2(1)/n, a=14.1(13) A, b=16.7(18) A, c=20.3(19) A, beta=107(4) degrees, Z=8) comprises distorted octahedral geometry around each tin atom by virtue of weakly bridging methanesulfonate [Sn(1A)-O(3B)=3.010, Sn(1B)-O(3A)=2.984 A] and (N,O) chelation of the carboxylate ligands. The spectral data of 1-4 suggest a similar structural motif in solution. The molecular structure of 6 (C38H53N2O10S2Sn2, monoclinic, P2(1)/c, a=11.339(2) A, b=14.806(3) A, c=24.929(5) A, beta=100.537(3) degrees, Z=4) reveals varying bonding preferences with monomeric units being held together by a bridging methanesulfonate [Sn(2)-O(5)=2.312(2) A] and a carboxylate group bonded to Sn(1) and Sn(2) atoms, respectively. Slow hydrolysis of compound 2 derived from 2-quinoline carboxylic acid in moist CH3CN affords the asymmetric distannoxane, [Bu2Sn(O2CC9H6N-2)-O-Sn(OSO2Me)Bu2]2 (7) (C27H45NO6SSn2, monoclinic, C2/c, a=21.152(3) A, b=13.307(2) A, c=26.060(4) A, beta=110.02(10) degrees, Z=8) featuring ladder type structural motif by virtue of unique mu2-coordination of covalently bonded oxygen atoms [O(6), O(6)#1] of the methanesulfonate groups.

Syntheses, characterization, and X-ray crystal structures of diorganotin(IV) derivatives of 2-pyridinethiolato-N-oxide

The diorganotin(IV) dichloride reacts with sodium 2-pyridinethiolato-N-oxide in a 1:1 ratio to produce [Me2SnCl(2-SpyO)] (1), [Et2SnCl(2-SpyO)] (2), [Bu2SnCl(2-SpyO)] (3), [Ph2SnCl(2-SpyO)] (4), and [(PhCH2)2SnCl(2- SpyO)] (5). The new complexes have been characterized by elemental analysis and IR and NMR (1H, 119Sn, and 13C) spectroscopy. On the basis of 119Sn NMR data the effective coordination number in solution is five. The structures 1 and 4 have been confirmed by X-ray crystallography. Crystals of 1 are triclinic with space group P[Formula: see text] and those of 4 are monoclinic, P21/n. The tin environment is a distorted trigonal bipyramid with the Cl and oxygen atoms in apical positions. Both complexes exhibit strong π–π stacking interactions. Key words: diorganotin, π–π stacking interaction, 2-pyridinethiolato-N-oxide, crystal structure.