Complexes of rhodium and iridium derived from 2,5-bis(pyrazol-1′-yl)-1,4-dihydroxybenzene

Abstract

The behaviour of the ligand 2,5-bis(pyrazol-1′-yl)-1,4-dihydroxybenzene (H2LL) towards RhI, IrI, RhIII and IrIII complexes is reported. This compound with two OH groups might act as a neutral ligand (H2LL), as a monoanionic ligand (HLL−) or as a dianionic ligand (LL2−). Complexes of all the three kinds have been isolated. In the case of H2LL, the compounds are not organometallic complexes but clathrates. The crystal and molecular structure of the host-guest complex [{(η5-C5Me5)RhCl}2-(μ-Cl)2]-H2LL (6a) is reported. Both the host and the guest have crystallographic Ci symmetry. No metal-H2LL chemical bonds are present, and van der Waals interactions between host and guest molecules govern the crystal packing. An heterobimetallic derivative [IrRh(η5-C5Me5)Cl2(LL)] (7c) has been isolated.