Synthetic routes to a range of thioaroyl complexes of tungsten and molybdenum are
reported. Successive treatment of [M(CO)6] (M = Mo, W) with LiC6H4OMe-4·LiBr, (CF3CO)2O, and 2,2-bipyridyl (bipy) provides [M(⋮CC6H4OMe-4)Br(CO)2(bipy)], which react with
methylthiirane to provide the thioaroyl complexes [M(η2-SCC6H4OMe-4)Br(CO)2(bipy)] and
the dithiocarboxylate complexes [M(η2-S2CC6H4OMe-4)Br(CO)2(bipy)]. [Mo(⋮CC6H4Me-4)(CO)2{HB(pz)3}] (pz = pyrazol-1-yl), [Mo(⋮CC6H4OMe-4)(CO)2{HB(pz)3}] (obtained from [Mo(⋮CC6H4OMe-4)Br(CO)2(γ-picoline)2] and K[HB(pz)3]), and [Mo(⋮C4H3S-2)(CO)2{HB(pz)3}]
(obtained directly from [Mo(CO)6], 2-thienyllithium, (CF3CO)2O, and K[HB(pz)3]) react with
methylthiirane to provide primarily [Mo(η2-SCR)(CO)2{HB(pz)3}] in addition to small
amounts of the corresponding dithiocarboxylates [Mo(η2-S2CR)(CO)2{HB(pz)3}], which also
arise from treatment of [Mo(η2-SCR)(CO)2{HB(pz)3}] with methylthiirane or elemental sulfur.
[Mo(⋮CC6H2Me3-2,4,6)(CO)2{HB(pz)3}] failed to react with methyllirane, while [Mo(⋮CC6H4OMe-4)(CO)2(η-C5H5)] provided exclusively the dithiocarboxylate derivative. The mixed
selenothiocarboxylates [Mo(η2-SSeCR)(CO)2{HB(pz)3}] (R = C6H4OMe-4, C4H3S-2) are
obtained by treating [Mo(η2-SCR)(CO)2{HB(pz)3}] with Li2Se2, while [Mo(η2-SOCC6H4Me-4)(CO)2{HB(pz)3}] results from hydrolysis of the product of the reaction of [Mo(η2-SCC6H4Me-4)(CO)2{HB(pz)3}] with [Me2SSMe]BF4. Alkylation of [Mo(η2-SCC6H4Me-4)(CO)2{HB(pz)3}] with [Et3O]BF4 provides the thiolatocarbene salt [Mo(η2-EtSCC6H4Me-4)(CO)2{HB(pz)3}],
while the analogues [Mo(η2-MeSCC6H4Me-4)(CO)2{HB(pz)3}]BF4 and [Mo(η2-MeSCC4H3S-2)(CO)2{HB(pz)3}]BF4 result from the reactions of [Mo(⋮CR)(CO)2{HB(pz)3}] with [Me2SSMe]BF4. The reactions of these salts with the nucleophiles Li[Et3BH] and Me3CSH provide the
thioalkyl complexes [Mo(η2-MeSCHC4H3S-2)(CO)2{HB(pz)3}], [Mo(η2-MeSCHC6H4OMe-4)(CO)2{HB(pz)3}], and [Mo(η2-MeSC(SCMe3)C6H4OMe-4)(CO)2{HB(pz)3}]. The heterobimetallic
thioaroyl complex [MoFe(μ-SCC6H4Me-4)(CO)5{HB(pz)3}] is obtained from the reaction of
[Mo(η2-SCC6H4Me-4)(CO)2{HB(pz)3}] with [Fe2(CO)9].