120311-63-9Relevant academic research and scientific papers
Coordination chemistry of higher oxidation states. 30. Five-coordinate cobalt(III) phosphine complexes. Spectroscopic and cobalt K-edge EXAFS studies
Levason, William,Ogden, J. Steven,Spicer, Mark D.
, p. 2128 - 2131 (2008/10/08)
The complexes [Co(PR3)2X3] (X = Cl, Br; PR3 = PMe3, PEt3, PMe2Ph, PEt2Ph, PEtPh2; X = Br, PR3 = PPh3) have been prepared by oxidation of the corresponding [Co(PR3)2X2] in dichloromethane with NOX at low temperatures. The intensely colored, paramagnetic (μ = 2.9-3.3 μB) Co(III) complexes are formulated as five-coordinate trigonal-bipyramidal species on the basis of vibrational and UV-visible spectroscopic studies and FAB mass spectra. Detailed assignments for the d-d and charge-transfer transitions in the UV-visible spectra are proposed. First-coordination-sphere bond lengths for the complexes [Co(PEt3)2X3] and [Co(PEt2Ph)2X3] were obtained by cobalt and bromine K-edge EXAFS spectroscopy (extended X-ray absorption fine structure), along with similar data for the model compounds [Co(PPh3)2X2]. For the cobalt(III) complexes average bond lengths are Co-P = 2.30 A?, Co-Cl = 2.20 A?, and Co-Br = 2.36 A?.
