- Synthesis of tris(cyclohexylisocyanide)bis(triphenylphosphine)cobalt(II) perchlorate. An example of unusual stabilization of the cobalt(II) oxidation state
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A cobalt(II) complex with alkylisocyanide and triarylphosphine ligands is reported. Tris(cyclohexylisocyanide)bis(triphenylphosphine)cobalt(II) perchlorate, [Co(CNC6H11)3(PPh3) 2](ClO4)2, was synthesized by PPh3 ligand-substitution in [Co(CNC6H11)4(AsPh3) 2](ClO4)2, in which the distribution of product among [Co(CNC6H11)3(PPh3)2](ClO4) 2, [Co(CNC6H11)3(PPh3) 2]ClO4, [Co(OPPh3)4](ClO4)2, and unreacted [Co(CNC6H11)4(AsPh3) 2](ClO4)2 was controlled in part by the concentration of PPh3 and reaction time. [Co(CNC6H11)3(PPh3) 2](ClO4)2 was also synthesized by AgClO4 oxidation of [Co(CNC6H11)3(PPh3) 2]ClO4. [Co(CNC6H11)3-(PPh3) 2](ClO4)2 is easily reduced to [Co(CNC6H11)3(PPh3) 2]ClO4 with N2H4.H2O and decomposes into [Co(OPPh3)4](ClO4)2 on prolonged dissolution in CH2Cl2 solution, especially under UV (365 nm) irradiation. Physical properties for [Co(CNC6H11)3(PPh3) 2](ClO4)2 and [Co(OPPh3)4](ClO4)2 support trigonal bipyramidal and tetrahedral solution and solid state stereochemistries, respectively, but both complexes have limited stability in most solvents.
- Becker, Clifford A. L.
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p. 1527 - 1542
(2008/10/09)
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