Monohelical quinquepyridine complexes of rhenium-(I) and -(III)

Abstract

Three 2,2′:6′,2″:6″,2‴:6‴,2‴′- quinquepyridine (qpy) complexes of rhenium, [Cl(OC)3Re1(qpy)ReI(CO)3Cl] 1, [(py)(OC)3ReI(qpy)ReI(CO) 3(py)][ClO4]2 2 (py = pyridine) and [ReIII(qpy)Cl2][ClO4] 3, have been prepared and their physicochemical properties studied. The crystal structures of 2 and 3 have been determined: 2 is a monohelical bimetallic complex with two fac-tricarbonyl rhenium(I) moieties linked by the qpy ligand and the five pyridyl rings of qpy divide in the fashion bipy-py-bipy (bipy = bipyridine fragment and py = pyridine spacer); 3 is a seven-co-ordinated monohelical rhenium(III) complex with pentagonal-bipyramidal geometry in which the two chloride ligands are trans to each other. Complexes 1 and 2 display photoluminescence in the spectral range 560-600 nm. The electrochemical properties of 2 and 3 are discussed.