Synthesis and structural characterisation of five-co-ordinate copper(I) and silver(I) 2,2′:6′,2″-terpyridine complexes

Abstract

Five-co-ordinate copper(I) and silver(I) 2,2′ : 6′,2″-terpyridine (terpy) complexes of the type [M(PPh₃)₂(terpy)]ClO₄(M = Cu or Ag) have been prepared by the reaction of terpy with either [Cu(PPh₃)₂(MeCN)₂]ClO₄ or [Ag(PPh₃)₂]ClO₄. The complexes have been characterised by spectroscopic methods and single-crystal X-ray diffraction analysis. In the crystal the complexes consist of discrete monomers of distorted trigonal-bipyramidal geometry, with the metal atoms co-ordinated to the distal terpyridine pyridyl rings [Cu–N 2.386(3), 2.535(4); Ag–N 2.614(2), 2.561 (2)Å] in axial sites. The co-ordination spheres are completed by the binding of the central pyridyl nitrogen atoms [Cu–N(2) 2.102(3), Ag–N(2) 2.457(2)Å] and two PPh₃ phosphorus atoms, which together define the equatorial planes. The ¹H and {¹H}-¹³C NMR spectra of [Cu(PPh₃)₂(terpy)]ClO₄ and [Ag(PPh₃)₂(terpy)]ClO₄ show that for each of the complexes the five-co-ordinate nature of the compounds is also retained in solution with the distal pyridyl rings being equivalent en the NMR time-scale.