Copper(I), Palladium(II) and Platinum(II) complexes of the 2- diphenylphosphino-1,10-phenanthroline ligand.

Abstract

Chapter 1 reviews the coordination behaviour of the 6-diphenylphosphino-2,2'-bipyridine, 6-anilino-2,2'-bipyridine, 2,2'-bipyridyl-6-one, 6-N-methylanilino-2,2'-bipyridine, 6-piperidyl-2,2'-bipyridine and 2-(phenylamino)-1,10-phenanthroline ligands. These ligands are all tridentate and contain well established chelating fragments viz., 2,2'-bipyridine and 1,10-phenanthroline. Thus the review of their coordination provides insight into the expected coordination of the 2-diphenylphosphino-1,10-phenanthroline (Ph2Pphen) ligand. The synthesis and characterisation of this ligand is described in Chapter 2. Chapter 3 describes the synthesis and characterisation of a range of Ph2Pphen ligand-bridged dicopper(l) complexes. It has been shown that Ph2Pphen reacts with a suitable copper(l) precursor, [Cu(MeCN)4]+, to form the versatile dinuclear [Cu2(u-Ph2Pphen)2(MeCN)2]2+complex cation containing two bridging Ph2Pphen ligands; the structure of the SbF6 salt of this complex has been determined X-ray crystallographically. This complex possesses labile acetonitrile ligands which have been substituted by a variety of neutral and anionic ligands. Complexes prepared this way include [Cu2(u-Ph2Pphen)2(u-CI)]+, [Cu2(u-Ph2Pphen)2(u-I)]+, [Cu2(u-Ph2Pphen)2(py)2]2 +, [Cu2(u-Ph2Pphen)2{u-S2CN(Et)2}]+, [Cu2(u-Ph2Pphen)2(n-bipy)]2+ and [Cu2(u-Ph2Pphen)2(n-phen)]2+. X-ray structure determinations have been completed for [Cu2(u-Ph2Pphen)2{u-S2CN(Et)2}]+ and [Cu2(u-Ph2Pphen)2(n-bipy)]2+. The X-ray crystal structures of these ligand-bridged complexes confirm that the phosphorus atom coordinates to one copper atom while the phenanthroline fragment chelates to the other copper atom with the result that each metal atom has a tetrahedral geometry. Chapter 4 reviews the synthesis and characterisation of palladium and platinum complexes of the 2-diphenylphosphino-1, 10-phenanthroline (Ph2Pphen) ligand. The comproportionation reaction with Pd(II) and Pd(0) afforded the dinuclear complex [Pd2(u-Ph2Pphen)2](BF4)2. The reaction of Ph2Pphen with platinum resulted in ill-defined products that could not be isolated and characterised.