Trigonal-Bipyramidal Tin(IV) Complexes Containing Tetradentate Tripodal Tristhiolatophosphine Ligands:  Synthesis, Characterization, Crystal Structure, and Transmetalation Reactions

• Published in: Inorganic chemistry 2005-01, Vol.44 (2), p.416-422
• Main Authors: Clark, Kerry A. (Fusie), George, T. Adrian
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic049328+

The reactions of the lithium salts of the proligands P(C6H4-2-SH)3 (P(HSH)3), P(C6H3-3-SiMe3-2-SH)3 (P(TMSSH)3), and P(C6H3-5-Me-2-SH)3 (P(MeSH)3) with RSnCl3 (R = Ph, Me, n-Bu), in THF at 0 °C, produced a series of trigonal-bipyramidal complexes of the type RSn(PS3). The crystal structures of PhSn(PHS3), PhSn(PTMSS3), and PhSn(PMeS3) reveal considerable distortion from local C 3 v symmetry for the Sn(PS3) group. Unique to PhSn(PMeS3) is the presence of intramolecular hydrogen bonding between one sulfur atom and an ortho H atom of the Ph group, creating a plane that includes this S atom and the corresponding C6H3 ring, a phosphorus atom, and the PhSn group. An analysis of the 1H, 13C, and 31P NMR data from a combination of HMQC, HMBC, 2-D COSY, and 1H{31P} NMR studies reveals that in solution the Sn(PS3) groups exhibit local C 3 v symmetry, even at low temperature. Byproducts frequently found in the synthesis of the proligands and tin complexes, and subsequent reactions, result from the oxidation of the trianionic tristhiolatophosphine ligand. The crystal structure of one of these, [OP(HS3)]2, shows that the molecule contains two ligands joined by a S−S bond. Within each original ligand the remaining two sulfur atoms form a S−S bond, and each phosphorus atom is oxidized. PhSn(PTMSS3) reacted with 2 equiv of FeCl3 in CH2Cl2 to produce the iron(IV) complex FeCl(PTMSS3). FeCl(PTMSS3) decomposed in the presence of excess FeCl3. Similar transmetalation reactions with FeCl2 or [Fe2OCl6]2- required the addition of ferrocenium ion to complete the oxidation of iron to 4+. RuCl(PTMSS3) was prepared by the reaction between PhSn(PTMSS3) and RuCl2(DMSO)4 without the addition of an external oxidizing agent.