Coinage Metal Complexes of Bis(quinoline-2-ylmethyl)phenylphosphine-Simple Reactions Can Lead to Unprecedented Results.

The different coordination behavior of the flexible yet sterically demanding, hemilabile P,N ligand bis(quinoline-2-ylmethyl)phenylphosphine (bqmpp) towards selected CuI , AgI and AuI species is described. The resulting X-ray crystal structures reveal interesting coordination geometries. With [Cu(MeCN)4 ]BF4 , compound 1 [Cu2 (bqmpp)2 ](BF4 )2 is obtained, wherein the copper(I) atoms display a distorted square planar and square pyramidal geometry. The steric demand and π-stacking of the ligand allow for a short Cu⋅⋅⋅Cu distance (2.588(9) Å). CuI complex 2 [Cu4 Cl3 (bqmpp)2 ]BF4 contains a rarely observed Cu4 Cl3 cluster, probably enabled by dichloromethane as the chloride source. In the cluster, even shorter Cu⋅⋅⋅Cu distances (2.447(1) Å) are present. The reaction of Ag[SbF6 ] with the ligand leads to a dinuclear compound (3) in solution as confirmed by 31 P{1 H} NMR spectroscopy. During crystallization, instead of the expected phosphine complex 3, a tris(quinoline-2-ylmethyl)bisphenyl-phosphine (tqmbp) compound [Ag2 (tqmbp)2 ](SbF6 )2 4 is formed by elimination of quinaldine. The Au(I) compound [Au2 (bqmpp)2 ]PF6 (5) is prepared as expected and shows a linear arrangement of two phosphine ligands around AuI .