Thioxoethenylidene (CCS) as a Bridging Ligand

Abstract

The reaction of [Mo(≡CBr)(CO) 2 (Tp*)] (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate) with [Fe 2 (µ-SLi) 2 (CO) 6 ] affords, inter alia, the unsymmetrical binuclear thioxoethenylidene complex [Mo 2 (µ:σ-C;η 2-C'S-CCS)(CO) 4 (Tp*) 2 ] which may be more directly obtained from [Mo(≡CBr)(CO) 2 (Tp*)] and Li 2 S. The reaction presumably proceeds via the intermediacy of the bis(alkylidynyl)thioether complex S{C≡Mo(CO) 2 (Tp*)} 2 which was, however, not directly observed but explored computationally and found to lie 78.6 kJ mol-1 higher in energy than the final thioxoethenylidene product. Computational interrogation of the molecules [M 2 (µ-C 2 S)(CO) 2 (Tp*) 2 ] (M = Mo, W, Re, Os) reveals three plausible coordination modes for a thioxoethenylidene bridge which involve a progressive strengthening of the CC bond and weakening of the M-C and M-S bonds, as might be expected from simple effective atomic number considerations. Scheme 1. Generation and Electrophilic Quenching of a Binuclear Alkynylthiolato Complex. 16

Construction of an iminoketenylidene

“…As observed for 1, 6l in solution both 3a and 3b exist as two rotamers with respect to the W-C-Pt-Br axis (ratio ca 4:1) that do not interconvert on the 31 P NMR timescale (25 °C, 162 MHz). The formation of 3a is accompanied by a shift of the carbido 13 4) Å] bond lengths fall within ranges established for octahedral tungsten 9 and squareplanar platinum centres, respectively. 10 The W1-C1-Pt1 spine is somewhat bent [168.4(3)°] so as to accommodate the phosphine ligand within a cleft provided by two pyrazolyl groups.…”

“…and [OsRhH(µ-CCO)(CO)3(dppm)2], 12c while a single example of a thioketenylidene complex [Mo2(µ-CCS)(CO)4(Tp*)2] has been reported. 13 The CCO and CCS molecules have conical (C¥v) symmetry with doubly degenerate p and p* orbital pairs, hence their triplet configuration. The frontier orbitals of hypothetical singlet CCNMe (6sMe), singlet CNPh (6sPh) and triplet (6tPh) are detailed in the ESI †,14,15 .…”

Diferrocenyl Thioketone: Reactions with (Bisphosphane)Pt(0) Complexes—Electrochemical and Computational Studies

“…The chemistry of metallathiiranes and related metallthiirenes attracts considerable attention of many groups and the nature of the metal-C=S bond in these compounds is a problem of current interest [65]. In addition, because of the well-documented importance of ferrocenyl functionalized compounds, the new complexes 3a – d offer a novel type of ferrocene- and platinum-containing sulfur systems for potential applications in material chemistry [66].…”

Selenoxopropadienylidene (CCCSe) as a Bridging Ligand

“…The synthetic approach appreciates similarities between the behavior of alkynylselenolate and selenocarbonylate nucleophiles toward metal halides by extending the principle to [ 3a ] − . The complex 4 joins a range of isoselenocarbonyl and isothiocarbonyl complexes and the recently reported thioxoethenylidene complex [Mo 2 (μ-CCS)(CO) 4 (Tp*) 2 ] in demonstrating the viability of bimetallics linked by linear carbon chalcogenide chains.…”