Synthesis of phosphinoferrocene amides and thioamides from carbamoyl chlorides and the structural chemistry of Group 11 metal complexes with these mixed-donor ligands

Abstract

The reaction of in situ generated 1′-(diphenylphosphino)-1-lithioferrocene with carbamoyl chlorides, ClC(E)NMe2, affords the corresponding (thio)amides, Ph2PfcC(E)NMe2 (E = O (2), S (3); fc = ferrocene-1,1′-diyl). These compounds as well as their analogues, Ph2PfcC(O)NHMe (4) and Ph2PfcC(O)NH2 (5), prepared from 1′-(diphenylphosphino)ferrocene-1-carboxylic acid (Hdpf) were studied as ligands for the Group 11 metal ions. In the reactions with [Cu(MeCN)4][BF4], the amides give rise to bis-chelate complexes of the type [Cu(L-κ2O,P)2][BF4]. Similar products, [Ag(L-κ2O,P)2]ClO4, are obtained from silver(i) perchlorate and 2, 4 or 5. In contrast, the reaction of AgClO4 with 3 produces a unique molecular dimer [Ag(3)(ClO4-κO)]2, where the metal centres are bridged by the sulfur atoms of the P,S-chelating thioamides. The reactions of 2-5 with [AuCl(tht)] (tht = tetrahydrothiophene) afford the expected gold(i)-phosphine complexes, [AuCl(L-κP)], containing uncoordinated (thio)amide moieties. Hemilabile coordination of the phosphinoamide ligands in complexes with the soft Group 11 metal ions is established by the crystal structure of a solvento complex, [Cu(5-κ2O,P)(5-κP)(CHCl3-κCl)][BF4], which was isolated serendipitously during an attempted crystallisation of [Cu(5-κ2O,P)2][BF4]. All of the compounds are characterised by spectroscopic methods, and the structures of several representatives of both the free phosphinoamides and their complexes are determined by X-ray diffraction analysis and further studied by DFT calculations and cyclic voltammetry. This journal is