The formation and reactivity of dimolybdenum acetylide anions; synthesis, structure, and thermal rearrangement of dimolybdenum η¹,η²-(4e)-vinylidene complexes

Abstract

Addition of PhCCLi to [Mo2(CO)4(η5-CmHn)2](n=m= 5; n= 7, m= 9) or ButLi to [Mo2(µ-HC2Ph)(CO)4(η5-CmHn)2] affords Li[Mo2(µ-C2Ph)(CO)4(η5-CmHn)2] characterised as [(Ph3P)2N]+ salts, protonation of the cyclopentadienyl salt affords [Mo2(µ-η1,η2-CCHPh)(CO)4(η-C5H5)2] which readily rearranges to [Mo2(µ-HC2Ph)(CO)4(η-C5H5)2], whereas methylation (CF3SO3Me) in CH2Cl2 or tetrahydrofuran affords respectively [Mo2{µ-η1,η2-CC(Ph)R}(CO)4(η-C5H5)2][R = Me or (CH2)4OMe] the latter being charcterised by X-ray crystallography; thermolysis of [Mo2{µ-η1,η2-CC(Ph)Me}(CO)4(η-C5H5)2] gives [Mo2{µ-η1,η3-CH.C(Ph)CH2}(CO)4(η-C5H5)2].