101316-11-4Relevant articles and documents
Synthesis, structures, and nonrigidity of heterotrimetallic alkyne clusters of the type CpNiCoM(CO)6(C2RR′) (M = Fe, Ru, Os)
Einstein, Frederick W. B.,Tyers, Kenneth G.,Tracey, Alan S.,Sutton, Derek
, p. 1631 - 1640 (2008/10/08)
A series of heterotrimetallic alkyne clusters of the type CpNiCoM(CO)6(C2RR′) (where M = Fe, Ru, Os) has been synthesized and structurally investigated. In all cases examined, the alkyne is oriented parallel to one edge of the trimetallic framework but the particular location varies. In the iron complex CpNiCoFe(CO)6(C2Et2) (1b), it is parallel to the Ni-Co edge and all carbonyls are terminal. In the ruthenium and osmium complexes CpNiCoRu(CO)6(C2Ph2) (2a) and CpNiCoOs(CO)6C2Ph2 (3a), the orientation is parallel to the Ni-Ru or Ni-Os edge and one of the CO groups adopts a semibridging position across the Co-Ru or Co-Os bond. A similar arrangement is observed in an iron complex when one of the carbonyl groups bound to cobalt is replaced by triphenylphosphine to give CpNiCoFe(CO)5(PPh3)(C2Ph2) (1d). Crystal data: 1b, monoclinic, P21/n, a = 9.559 (3) ?, b = 12.573 (5) ?, c = 16.175 (4) ?, β = 104.42 (3)°, Z = 4, V = 1883 ?3, λ(Mo Kα1) = 0.709 30 ?, μ(Mo Kα) = 26.4 cm-1, dcalcd = 1.72 g cm-3, dmeasd = 1.74 g cm-3, R = 0.029 and Rw = 0.033 for 1387 observed reflections, with I ≥ 2.3σ(I) (1748 measured with 40°≥ 2θ ≥ 3°); 1d, monoclinic, P21/c, a = 11.698 (2) ?, b = 14.768 (3) ?, c = 22.616 (4) A, β = 111.82 (1)°, Z = 4, V = 3627 ?3, λ(Mo Kα1) = 0.709 30 ?, μ(Mo Kα) = 14.7 cm-1, dcalcd = 1.48 g cm-3, dmeasd = 1.51 g cm-3, R = 0.057 and Rw = 0.070 for 1109 observed reflections, with I ≥ 2.3σ(I) (2316 measured with 35°≥ 2θ ≥ 3°); 2a, monoclinic, P21/c, a = 9.964 (2) ?, b = 9.5112 (6) ?, c = 24.835 (2) ?, β = 90.11 (1)°, Z = 4, V = 2353 ?3, λ(Mo Kα1) = 0.709 30 ?, μ(Mo Kα) = 21.7 cm-1, dcalcd, = 1.78 g cm-3, dmeasd = 1.80 g cm-3, R = 0.036 and Rw = 0.042 for 1816 observed reflections with I ≥ 2.3σ(I) (3100 measured with 45°≥ 2θ ≥ 3.5°); 3a, monoclinic, P21/c, a = 9.950 (2) ?, b = 9.505 (2) ?, c = 24.813 (4) ?, β = 90.10 (3)°, Z = 4, V = 2347 ?3, λ(Mo Kα1) = 0.70930 ?, μ(Mo Kα) = 69.4 cm-1, dcalcd = 2.03 g cm-3, dmeasd = 2.11 g cm-3, R = 0.033 and Rw = 0.039 for 2503 reflections with I ≥ 2.3σ(I) (3063 measured with 45°≥ 2θ ≥ 3°). The variable-temperature 1H NMR spectra of 1c (Fe), 2c (Ru), and 3c (Os), containing the unsymmetrical alkyne MeC2Ph, indicate that the clusters are nonrigid and the alkyne substituents interchange position by rotation of the alkyne moiety on the face of the metal triangle. Examination of the C2Et2 complexes shows this to be nondissociative and to involve no transfer from one face of the metal triangle to the other.
