Facile cleavage of a phenyl group from SbPh3 by dirhenium carbonyl complexes

The complex Re 2 (CO) 8 [μ-η 2 -C(H) C(H)Bu n ](μ-H) ( 1 ) reacts with SbPh 3 at 68 °C to yield the new σ-phenyl dirhenium complex Re 2 (CO) 8 (SbPh 3 )(Ph)(μ-SbPh 2 ) ( 4 ) in 72% yield. Compound 4 contains two rhenium atoms held together by a bridging SbPh 2 ligand. One rhenium atom contains a σ-phenyl group. The other rhenium atom contains a SbPh 3 ligand. Compound 4 was also obtained in 34% yield from the reaction of Re 2 (CO) 10 with SbPh 3 in the presence of UV–Vis irradiation together with some monorhenium products: HRe(CO) 4 SbPh 3 ( 5 ), Re(Ph)(CO) 4 SbPh 3 ( 6 ) and fac -Re(Ph)(CO) 3 (SbPh 3 ) 2 ( 7 ) in low yields. Complex 4 is split by reaction with an additional quantity of SbPh 3 to yield the monorhenium SbPh 3 complexes 6 , 7 and mer -Re(Ph)(CO) 3 (SbPh 3 ) 2 ( 8 ) that contain a σ-phenyl ligand. When 4 was treated with hydrogen, the phenyl ligand was eliminated as benzene and the dirhenium complexes Re 2 (CO) 8 (μ-SbPh 2 )(μ-H) ( 10 ), and Re 2 (CO) 7 (SbPh 3 )(μ-SbPh 2 )(μ-H) ( 11 ), were formed that contain a bridging hydrido ligand. The doubly SbPh 2 -bridged dirhenium complex Re 2 (CO) 7 (SbPh 3 )(μ-SbPh 2 ) 2 ( 9 ) that has no metal–metal bond was also formed in these two reactions.