104439-72-7Relevant academic research and scientific papers
Cobalt(I) complexes: Synthesis and molecular and X-ray structures of group 14 (η4-metallole)tris(trimethylphosphine)cobalt tetraphenylborate complexes
De Carvalho, L. C. Ananias,Dartiguenave,Dahan,Dartiguenave,Dubac,Laporterie,Manuel,Iloughmane
, p. 2205 - 2211 (2008/10/08)
Reaction of CoBr(PMe3)3 (4) with 1,1,3,4-tetramethylmetalloles (Si, 2; Ge, 3) in presence of NaBPh4 yielded [Co(metallole)(PMe3)3]BPh4 complexes (Si, 5; Ge, 6). The crystal structures of 5 and 6 have been determined by X-ray diffraction techniques. They are isomorphous and crystallize in the orthorhombic system P212121. Crystal data: for 5, a = 16.064 (2) ?, b = 10.304 (2) ?, c = 25.680 (4) ?; for 6, a = 16.088 (2) ?, b = 10.272 (2) ?, c = 25.805 (3) ?, Z = 4. R = 0.050 in 5 for 2726 "observed" reflections, while R = 0.056 in 6 for 2911 "observed" reflections. The structures consist of independent BPh4 anions and Co cations. In both complexes the cobalt is in a distorted square-pyramidal environment with an apical and two basal PMe3 ligands. The difference between the apical and basal Co-P bond lengths is greater in 5 (Co-Pa = 2.298 (1) ? compared to Co-Pb = 2.229 (2) and 2.230 (2) ?) than in 6 (2.251 (3) ? compared to 2.206 (3) and 2.225 (3) ?). The metalloles are η4-coordinated by their dimethylbutadiene moiety, which is roughly planar and makes an angle of 77.1° in 5 and of 78.5° in 6 to the basal plane. Bending of the metallole ring after coordination is 41.2° in 5 and 44.5° in 6. Co is located 0.706 ? above the equatorial plane in 5 and 0.664 ? in 6. The Co-metallole double-bond distance is shorter in 6 (average 2.059 (10) ?) than in 5 (average 2.102 (7) ?). Multinuclear NMR spectra (183-297 K) indicate that both complexes are stereononrigid.
