Crystal structures of a bis(cyclopentadienyl)(Z)-enyne framed manganese(I)-rhenium(I) complex and its [Co2(CO)8] adduct

The X-ray structural determination of the manganese(I)-rhenium(I) complex [(OC)3Mn{eta-5-C5H4)(Z)CH = CHC = C(eta-5-C5H4)}Re(CO)3] 1 has been carried out. The structural data show that the (Z)-enyne linkage between the two cyclopentadienyl rings, despite the conjugation that would keep the ligand framework coplanar, allows twisting of the two cyclopentadienylmetal units. Because of this characteristic the Mn Re interatomic distance (6.1 angstrom) is much shorter than in similar bis(cyclopentadienyl)-linked heterobimetallic complexes. Reaction of 1 with [Co2(CO)8] affords quantitatively the corresponding dicobalt tetragonal pyramidal adduct [(OC)3Mn{eta-5-C5H4)(Z)CH = CHC-(OC)3Co-Co(CO)3-C-(eta-5-C5H4)}Re(CO)3]2 the X-ray structure of which has been determined. The presence of the dicobalt unit on the triple bond heavily affects the carbon chain connecting the two cyclopentadienyl rings, and the metal centres are at a larger distance than in 1. Crystal data: 1, triclinic, space group P1BAR, a = 6.546(1), b = 11.066(2), c = 13.451 (3) angstrom, alpha = 96.06(2), beta = 100.46(2), gamma = 96.31 (1)-degrees, R(F) = 0.0466, R'(F) = 0.0542 for 2710 observed reflections with F > 4.0-sigma(F); 2, triclinic, space group P1BAR, a = 9.825(3), b = 11.853(4), c = 13.662(3) angstrom, alpha = 109.41 (2), beta = 1 04.36(2), gamma = 99.16(2)-degrees, Z = 2, R(F) = 0.0325, R'(F) = 0.0352 for 5913 observed reflections with F > 4.0-sigma(F).