Paramagnetic cobalt(III) compounds of chromophoric Type [Co(N)4,X]. Part II. Further preparations, spectral data, and some reactions.

Abstract

A further extension is reported of the series of five-coordinate cobalt(III) compounds [Co(N)4X] (X = Cl, Br), derived from quadridentate dianionic Schiff base ligands such as 1,2-bis-(o-iminobenzylideneimino)ethane. In this new series, the effects of both electron-donating and -withdrawing ligand substituents have been investigated. Solid, crystalline compounds were isolated by oxidising the previously reported cobalt(II) species, and they were characterised by their i.r. spectra and X-ray powder diffraction patterns. All have room-temperature magnetic moments of ∼ 3 B.M., attributable to thermal population of a triplet state of the molecule, and they have characteristic electronic spectra with a strong absorption at 12,000→13,000 cm−1 (ε ⩽ 9000 l M−1 cm−1).