TY - JOUR
T1 - Complexes with Phosphinomethanes and-methanides as Ligands. 10.1 Formation, Structure, and Properties of {[(PMe2CH2PMe2)(PMe3)Co]2PMe2}, a Dinuclear, Odd-Electron Cobalt Complex of Formal Oxidation State Co2+. Electronic Structure of [CoL3]2PR2 Radicals
AU - Karsch, Hans H.
AU - Milewski-Mahrla, Beatrix
AU - Besenhard, Jürgen O.
AU - Hofmann, Peter
AU - Stauffert, Peter
AU - Albright, Thomas A.
PY - 1986/10
Y1 - 1986/10
N2 - The paramagnetic, dinuclear complex| [(PMe3)(Me2PCH2PMe2)Co]2PMe2} (1) is formed by P-C cleavage of a phosphine-Co(0) intermediate. Its solid-state structure was determined by X-ray diffraction methods (hexagonal, space group P63/m; Z = 6; a = b = 16.285 (7), c = 19.296 (6) A; R = 0.068, Rw= 0.062, w = 1 /σ2(Fo) for 130 refined parameters and 817 observables with F0≥ 4.0σ(Fo)). Each cobalt atom binds four P atoms in a pseudotetrahedral environment. Two Me2PCH2PMe2 groups and one PMe2 group bridge the two cobalt atoms. The Co-Co distance is 2.603 (3) A. The magnetic moment (μeff = 1.85 (15) μB)is temperature-independent and corresponds to the presence of one unpaired electron. This is in accord with MO calculations (EHT), which show the delocalized electron to occupy a Co-Co antibonding (δ*) and mainly metal centered SOMO. The results are compared with model calculations for the related complex| [(CO)3Co]2P[CH(SiMe3)2]2). In both cases actual geometries and ligand donor or acceptor properties of the Co2L6 skeleton have a pronounced effect upon energy and composition of the singly occupied molecular orbital. The molecular orbital results are in accord with cyclovoltammetric measurements, which reveal the existence of one reduction and three distinct oxidation steps for 1, which are quasi-reversible. The diamagnetic monocation 1+ is obtained by chemical oxidation of 1 and isolated as the BF4-salt. This complex cation exhibits fluxional behavior in solution (NMR), analogous to so-called molecular “A-frames”.
AB - The paramagnetic, dinuclear complex| [(PMe3)(Me2PCH2PMe2)Co]2PMe2} (1) is formed by P-C cleavage of a phosphine-Co(0) intermediate. Its solid-state structure was determined by X-ray diffraction methods (hexagonal, space group P63/m; Z = 6; a = b = 16.285 (7), c = 19.296 (6) A; R = 0.068, Rw= 0.062, w = 1 /σ2(Fo) for 130 refined parameters and 817 observables with F0≥ 4.0σ(Fo)). Each cobalt atom binds four P atoms in a pseudotetrahedral environment. Two Me2PCH2PMe2 groups and one PMe2 group bridge the two cobalt atoms. The Co-Co distance is 2.603 (3) A. The magnetic moment (μeff = 1.85 (15) μB)is temperature-independent and corresponds to the presence of one unpaired electron. This is in accord with MO calculations (EHT), which show the delocalized electron to occupy a Co-Co antibonding (δ*) and mainly metal centered SOMO. The results are compared with model calculations for the related complex| [(CO)3Co]2P[CH(SiMe3)2]2). In both cases actual geometries and ligand donor or acceptor properties of the Co2L6 skeleton have a pronounced effect upon energy and composition of the singly occupied molecular orbital. The molecular orbital results are in accord with cyclovoltammetric measurements, which reveal the existence of one reduction and three distinct oxidation steps for 1, which are quasi-reversible. The diamagnetic monocation 1+ is obtained by chemical oxidation of 1 and isolated as the BF4-salt. This complex cation exhibits fluxional behavior in solution (NMR), analogous to so-called molecular “A-frames”.
UR - https://www.scopus.com/pages/publications/4244094381
U2 - 10.1021/ic00241a022
DO - 10.1021/ic00241a022
M3 - Article
AN - SCOPUS:4244094381
SN - 0020-1669
VL - 25
SP - 3811
EP - 3821
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 21
ER -