THE CRYSTAL AND MOLECULAR STRUCTURE OF CHLORODICARBONYLPYRIDYLIRIDIUM(I) IrCl(CO) 2 (C 5 H 5 N)

Abstract

In a continuing investigation of the structural properties of the heavy d⁸ metal complexes¹ in which metal-metal interactions are indicated, the crystal structure of chlorodicarbonylpyridyliridium(I) has been determined. In the past the square-planar complexes of Ir(I) and Rh(I) have most commonly been proposed to form linear chains,² the validity of which has been shown in several studies, ^{3, 4} However, the dimeric nature of the complex 3-methyl-2,4- pentanedionatodicarbonyliridium(I)¹ has subsequently cast doubt on the generality that chain interactions can always account for the properties of this type of complex. This question has thus prompted our investigation of other square-planar d8 complexes such as that decribed in this paper. This complex, IrCl(CO)₂ (pyridine), was first prepared and characterized by Hieber and Frey.⁵ Like dicarbonylacetylacetonatoiridium(I)⁴, electrical conductivity studies of this complex⁶ are also highly indicative of metal-metal interactions. It is thus important to reveal the actual structural details. The results of our studies are given here.