η²-Alkynyl and Vinylidene Transition Metal Complexes. 8.¹ Synthesis of Bimetallic Tungsten Gold Complexes by Addition of ClAuPPh₃ to the Acetylide Li[(η⁵-C₅H₅)(CO)(NO)W(C⋮C−R)]

Abstract

Tungsten acetylide complexes 1 [R = C(CH3)3; R = C6H5; R = p-tolyl] have been found to react in THF at −60 °C with ClAuP(C6H5)3 to yield the bimetallic tungsten gold complexes [(η5-C5H5)(NO)(μ-CO)(μ-C⋮C−R)W−AuP(C6H5)3] [8a, R = C(CH3)3; 8b, R = C6H5; 8c, R = p-tolyl] with semibridging carbonyl and alkynyl ligands. The molecular structure of 8a was determined by single-crystal X-ray diffraction analysis. Variable-temperature NMR studies of 8a showed fluxional behavior and at −80 °C the presence of three isomers.

Reaction and subsequent transformation of anionic acetylide–carbene complexes using the Ph3PAu+ fragment

“…We have recently described 1-3 a number of rearrangements that occur upon treatment of anionic Fischer-type carbene complexes with the metal fragment isolobal to the proton, Ph 3 PAu + . 4 Without exception the gold atom is found attached to the original carbene carbon atom, with the ligand functioning formally as an anionic entity, e.g. substituted vinyl, acyl or imodoyl (Scheme 1).…”

Gold–Heterometal Interactions and Bonds

“…Heterometallic compounds with an unsupported Au-metal bond are common for molybdenum derivatives [120][121][122][123][124] and recent examples are complexes related to the chromium derivative 129, that is (Ph 3 P)AuMo (CO) 3 (h 5 [141]. Both neutral and ionic cluster compounds containing m 3 -p-tolylmethylidyne or m 3 -ethylidyne groups bridging a trimetallic core with at least one gold atom are well represented in the chemistry of Au-W compounds [126,131,135,136,145,146].…”

“…In contrast, dinuclear complexes with an unsupported Au-W bond are much rarer[113,129], a recent example being the tungsten analog 139 of compound 136 [Au-W 2.7121(5)/2.7060(5) Å][113]. Much more common are dinuclear and polynuclear compounds in which the metal centers of an Au-W bond are bridged by m-arylmethylidene[130,131], m-arylmethylidyne[132][133][134][135][136][137][138][139][140], m-C:C t Bu[141], m-CN (Et)Me[142], m-CO or m-CS ligands[127,[143][144][145].A recent example, (Ph 3 P)AuW(m-CO)(m-C:C t Bu)(h 5 -Cp)(NO) 140, features both alkynyl and carbonyl groups supporting the Au-W bond [2.803(3) Å] (Figure 4.36a)…”

The chemistry of the carbon–transition metal double and triple bond: annual survey covering the year 2002

“…A mechanism involving formation of a cationic vinylidene (431) through coupling of the tungsten acetylide and aldehyde-Lewis acid complex, followed by nucleophilic attack by the alcohol to form an alkenyltungsten complex (432), followed by elimination of water to form a cationic Fischer carbene complex (433), followed by deprotonation was proposed. Deprotonation of a neutral tungsten(0)-vinylidene complex afforded an anionic alkynyltungsten complex [510]. Various metallacumulene-chromium complexes (e.g.…”