The remarkable role of steric factors in the reactions of alkynes (HC
CH and MeC
CMe)with ditungsten hexa-alkoxides: crystal and molecular structures of W2(OPri)6(py)2(µ-C2H2), W2(OCH2But)6(py)2(µ-C2Me2), and W2(OPri)6(µ-C4R4)(C2R2), where R = H and Me (py = pyridine)
Abstract
Ethyne and but-2-yne react with hydrocarbon solutions of W2(OR)6 compounds in the presence of pyridine (py) to produce the compounds W2(OR)6(py)2(µ-C2R′2), W2(OR)6(η-C4R′4)(C2R′2), or R′CW(OR)3, depending on the nature of the alkoxy group and the alkyne substituent, R′