摘要:
The phenylacetylide-bridged heterobinuclear complexes [RhIr(CO)(2)(mu-eta(1):eta(2)-C2Ph)(dppm)(2)][X] (X = BF4, SO3CF3; dppm = Ph2PCH2PPh2) (1) react with carbon disulfide to give several products. At temperatures between - 60 and - 80 degrees C the first product, [RhIr(CO)(eta(2)-CS2)(mu-CO)(mu-eta(1):eta(2)-C2Ph)(dppm)(2)][X] (2), is the result of CS2 coordination at Ir. Upon warming, two products are formed as a result of condensation of two CS2 groups. In [RhIr(CO)(mu-eta(1):eta(3)-CC(Ph)SCSCS2)(mu-CO)(dppm)(2)][X] (3); the resulting C2S4 fragment has also condensed at the beta-carbon of the acetylide group to give a heteroatom-substituted vinylidene group. The other identified product, [RhIr(CO)(C2S4)(mu-C2Ph)(mu-CO)(dppm)(2)][X] (4), is very similar to 3 apart from the absence of coupling of the C2S4 moiety and the acetylide group. Compound 3 appears to be formed independently of 4, but also slowly transforms into 4 by cleavage of a C-S bond. The reaction of 1 with (BuNCS)-Bu-n at - 80 degrees C yields [RhIr(CO)(eta(2) -(SCNBu)-Bu-n)(mu-CCPh)(mu-Co)(dppm)(2)][X] (5), analogous to 2, and upon warming this rearranges to the isothiocyanate-bridged product [RhIr(CCPh)(CO)(2)(mu-(SCNBu)-Bu-n)(dppm)(2)][X] (6). Compound 6 undergoes S-C bond cleavage to yield [RhIr(CCPh)(CO)((CNBu)-Bu-n)(mu-S)(mu-CO)(dppm)(2)][X] (7), slowly at ambient temperature or within hours under reflux. Although no simple adducts analogous to 5 and 6 were observed with (BuNCS)-Bu-t, refluxing 1 in the presence of an excess of this substrate yields [RhIr(CCPh)(CO)((CNBu)-Bu-t)(mu-S),(mu-CO)(dppm)(2)][X] (9) as the major product along with smaller amounts of [RhIr(CCPh)(CO)((CNBu)-Bu-t)(mu-S)(mu-CO)(dppm)(2)][X] (8), analogous to compound 7, Refluxing 1 in the presence of excess (BuNCS)-Bu-n also yields some of the bis-n-butylisocyanide product, analogous to 9. The X-ray structures of compounds 3 (SO3CF3- salt), 7 (BF4- salt) and 9(BF4- salt) are reported. (C) 2000 Elsevier Science S.A. All rights reserved.