Tertiary phosphine complexes of the cobalt(III) NN′-ethylenebis(salicylideneiminato) and bisdimethylglyoximato systems

Abstract

Complexes of the types [CosalenPR3]X, [Cosalen(PR3)2]X, [Co(DH)2PPh3X], and [Co(DH)2(PR3)2]ClO4, many of them new, have been prepared and characterized with respect to 1H nmr spectra, ligand field parameters, and equilibrium constants for the formation of the 2:1 salen complexes. 1H chemical shifts appear to be dominated by anisotropic rather than inductive effects, while the relative tertiary phosphine ligand field strengths appear to correlate with the steric requirements of the phosphines as well as their expected σ donor strengths. Ease of formation of the 2:1 salen complexes is determined largely by steric effects, as are trans effects in the DH systems.