Abstract
A number of complexes of substituted phenolate ions with divalent metals have been prepared. These are of the form M(OR)2(L)2, where M = Co(Il), Ni(II) or Cu(ll); OR = 4-formyl-2-methoxyphenolate, 2-ethxy-4-formylphenolate, 2-methoxy-4-nitrophenolate, 2-methyl-4-nitrophenolate, 2,4,6-trichIorophenolate or pentachlorophenolate; L = water, pyridine, ammonia or -1/2 N,N,N,N-tetramethylethylenediamine. Some compounds possess additional molecules of water. An attempt has been made to establish the stereochemistry of the copper(II) complexes using their solid state electronic spectra, most of which fall into one of three categories, by comparison to compounds of known structure. The crystal and molecular structure of two copper complexes, namely bis(2-methoxy-4-nitrophenolato)bis(pyridine)copper(II) and Bis(4-formyl-2-methoxyphenoleto)bis(pyridine)copper(II) monohydrate, have been determined by single crystal X-ray methods. The copper(II) ion has a distorted six co-ordinate environment in both complexes, which are monomeric with the phenolate ions bidentate and chelating through the phenolic- and methoxy-oxygens. The solid state electronic spectra of the cobalt(II) and nickel(II) complexes are consistent with six co-ordination about the metal . ion. However, whereas those of the nickel(II) complexes are-typical of regular octahedral species, the cobalt(II) spectra suggest that considerable distortion from regular octahedral stereochemistry is present. Probable structures are proposed for all the complexes, although in some cases there are several possibilities. These arise either because some compounds contain additional molecules of water, the bonding role of which is uncertain, or, in the case of copper(II), the metal ion stereochemistry is in doubt. The behaviour of the three divalent metal ions with these ligands is compared and contrasted where appropriate.