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)₃Re^I(qpy)Re^I(CO)₃Cl]1, [(py)(OC)₃Re^I(qpy)Re^I(CO)₃(py)][ClO₄]₂2(py = pyridine) and [Re^III(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.