Synthesis, structure, and electrochemistry of acetylide and oxo incorporated mixed Fe/Mo and Fe/W chalcogen-bridged clusters

Abstract

Thermolysis of a benzene solution containing [Fe2Mo(CO)(10)(mu(3)-Se)(2)] (1) and [(eta(5)-C5Me5)W(CO3)CdropCPh] (2) under an optimum concentration of oxygen in the reaction medium yields the cluster [(eta(5)-C5Me5)MoWFe2(O)(mu(3)-Se)(mu(4)-Se)(CO)(8)(CCPh)] (3), containing a monooxygenated metal center. Under an argon atmosphere, thermolysis of [Fe2Mo(CO)(10)(mu(3)-S)(2)] (4) with [(eta(5)-C5Me5)W(CO)(3)CdropCPh] (2) in benzene leads to an oxygen-free mixed metal cluster [(eta(5)- C5Me5)MoWFe4(mu(3)-S)(3)(mu(4)-S)(CO)(14)(CCPh)] (9). Interestingly, on reacting a benzene solution of 4 with 2 and [(eta(5) -C5Me5)Mo(CO)(3)CdropCPh] (5) under an increased concentration of oxygen in the reaction medium gave way to clusters [(eta(5)-C5Me5)WMo2(mu-O)(2)(mu-S)(mu(3)-CCPh){Fe-2(CO)(6)(mu(3)-S)(2)}(2)] (6), [(eta(5)-C5Me5)WMo(O)(2)(mu-O)(mu-CCPh){Fe-2(CO)(6)(mu(3)-S)(2)}] (7), and [(eta(5)-C5Me5)Mo-3- (mu-O)(2)(mu-S)(mu(3)-CCPh){Fe-2(CO)(6)(mu(3)-S)(2)}(2)] (8) with higher oxygen content. The structures of the newly formed clusters 3, 6, 7, 8, and 9 were established crystallographically and the oxo-containing Mo and W clusters investigated electrochemically.