7428-60-6Relevant articles and documents
Cobalt(II) and iron(II) tris(trimethylsilyl)siloxides: synthesis, structure and reactivity
Chesnokova, Tatiana A,Zhezlova, Elena V,Kornev, Alexander N,Fedotova, Yana V,Zakharov, Lev N,Fukin, Georgy K,Kursky, Yurii A,Mushtina, Tatiana G,Domrachev, Georgy A
, p. 20 - 31 (2007/10/03)
A series of cobalt(II) and iron(II) siloxide complexes, [(Me3Si)3SiO]2M(Ln) {M=Co, Ln=none (1), (THF) (3), (THF)2 (4), (DME) (5), (MeCN)2 (6), (PhCN)2 (7), (2,2′-dipyridyl) (8), 4,4′-dipyridyl (9), (Ph3P)2 (10); M=Fe, Ln=none (2), (2,2′-dipyridyl) (11) were prepared by the reaction of metal silylamides [(Me3Si)2N]2M (M=Co, Fe) with tris(trimethylsilyl)silanol. The crystal structures of compounds 1 and 11 have been determined by the X-ray diffraction method. Complex 1 has a dimeric structure with two [(Me3Si)3SiO]2Co units bonded via the two μ2-O atoms. The central [Co(μ2-O)]2 cycle has a 'butterfly shape' being bent along the bridging oxygen atoms. The dihedral angle between the Co(1)O(4)Co(2) and Co(1)O(3)Co(2) planes is 143.1°. The μ2-bridging and terminal CoO distances are 1.945(7)-1.963(7) and 1.781(8), 1.793(7) A?, respectively. The Co?Co distance in 1 is relatively short, 2.735(2) A?. However, the high value of magnetic moment (6.0 μB) of compound 1 indicates the absence of a direct interaction between the Co atoms in 1. The molecule of 11 is monomeric. The Fe atom is bonded to 2,2′-dipyridyl and two terminal OSi(SiMe3)3 groups and has a distorted tetrahedral environment. The FeN(1), FeN(2) and FeO(1), FeO(2) distances in 11 are 2.148(1), 2.164(1) and 1.863(1), 1.900(1) A?, respectively. Addition of one equivalent of PhCCH to 7 results in the substitution of one tris(trimethylsilyl)siloxy-group with the formation of the diamagnetic dimer {(PhCN)(PhC2)CoOSi(SiMe3)3}2. Subsequent addition of PhC2H causes its oligomerisation. Complexes 1, 3 and 10 absorb carbon monoxide at ambient temperature and pressure while the others remain unreactive. Electronic spectra show fluxional behavior of complexes 1, 3 and 4 in solution.
