Synthesis and characterization of Tetrakis(Alkylisocyanide) Bis(Triarylphosphine)Cobalt(III) complexes by Labile ligand substitution in intermediate-spin six-coordinate Co(III) complexes

• Published in: Journal of coordination chemistry 2004-03, Vol.57 (4), p.329-336
• Main Authors: Becker, Clifford A.L., Mmatli, Edward Eddie
• Format: Article
• Language: English
• Subjects: Alkylisocyanide; Cobalt(III) complexes; Intermediate-spin complexes; Ligand substitution; Triarylphosphine
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958970410001671219

Three intermediate-spin six-coordinate Co(III) complexes, [Co(CNCH 2 Ph) 4 {OAs(C 6 H 4 Me-p) 3 } 2 ](BF 4 ) 3 (1), [Co(CNC 6 H 11 ) 4 (OSbPh 3 ) 2 ](ClO 4 ) 3 (2), and [Co(CNCH 2 Ph) 4 (OSbPh 3 ) 2 ](BF 4 ) 3 (3), undergo rapid ligand substitution with selected triarylphosphines at 0°C. Complexes 1, 2, and 3 react with P(C 6 H 4 OMe-p) 3 , 1 and 2 react with PPh 3 , and 2 reacts with P(C 6 H 4 Me-p) 3 , to produce trans-[Co(CNR) 4 (PR′ 3 ) 2 ]X 3 complexes in very high yields. Attempted reaction with P(C 6 H 4 Cl-p) 3 yields a Co(I) complex. The triarylphosphine-alkylisocyanide Co(III) complexes were characterized by magnetic susceptibility, and solution and solid state IR and electronic spectra. The Co(III) complexes are diamagnetic, but exhibit various degrees of reduction in different solvents.