Spectroscopic studies on some compounds (including dimorphic solids) of platinum(II) with 2,2′-bipyridyl and its analogues

Abstract

The structure and spectroscopic properties of the red form of [Pt(bipy)Cl₂](bipy = 2,2′-bipyridyl) are discussed. Some novel cases of dimorphism are reported. Preparation of the new complexes [Pt(LL)Cl₂](LL = 6,6′-Me₂-bipy, 5,5′-Me₂bipy, 4,4′-Me₂bipy), [Pt(LL)₂]²⁺(LL = 5,5′-Me₂bipy, 4,4′-Me₂bipy), [Pt(bipy)(py)₂]²⁺, [Pt(bipy)-(NO₃)(OH)], and [Pt(bipy)(H₂O)(OH)]⁺(py = pyridine) are described and ¹H n.m.r. assignments of [Pt(bipy)-(OH)₂] and [Pt(bipy)₂]²⁺ have been made by comparison with the corresponding methyl-substituted 2,2′-bipyridyl derivatives. At pH ca. 6, the 220 MHz ¹H m.r. spectrum of [Pt(bipy)₂]²⁺ is consistent with a square planar or tetrahedrally distorted structure.