SYNTHESES AND REACTIVITY OF HETEROMETALLIC OXO-ACETYLIDE CLUSTER COMPOUNDS. SKELETAL REARRANGEMENT AND CONVERSION OF ACETYLIDE TO ALKENYL, ALKYLIDENE, AND ALLENYL LIGANDS ON A WRE2 FRAMEWORK

Oxidation of the mixed-metal cluster Cp*WRe2(CCR)(CO)9 (1, Cp* = C5Me5; R = Ph and C(Me)CH2) with dioxygen in solution at 100 °C affords the oxo clusters Cp*W(O)Re2(CCR)(CO)8, (2a, R = Ph; and 2b, R = C(Me)CH2. Treatment of 2 with CO at 110 °C provides the clusters Cp*W(O)Re2(CCR)(CO)9 (4), which revert back to 2 by removal of one CO upon thermolysis. Both compounds 2 and 4 contain an open triangular skeletal arrangement, a multisite bound acetylide ligand, and a terminal oxo ligand attached to the W atom. Complex 2a reacts with dihydrogen to form a mixture of three cluster complexes:  the acetylide cluster Cp*WRe2(μ-O)(μ-H)2(CCPh)(CO)6 (5a), alkenyl cluster Cp*W(O)Re2(CHCHPh)(CO)8 (6a), and the alkylidene cluster Cp*W(O)Re2(μ-H)(CHCH2Ph)(CO)8 (7a), which are formally produced by addition of two H2 and elimination of two CO molecules, transferring one H2 to the acetylide ligand and incorporation of one H2 molecule to 6a, respectively. For the vinylacetylide compound 2b, it reacts with dihydrogen under sim...