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 Cu I , Ag I and Au I species is described. The resulting X-ray crystal structures reveal interesting coordination geometries. With [Cu(MeCN) 4 ]BF 4 , compound 1 [Cu 2 (bqmpp) 2 ](BF 4 ) 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). Cu I complex 2 [Cu 4 Cl 3 (bqmpp) 2 ]BF 4 contains a rarely observed Cu 4 Cl 3 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[SbF 6 ] 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 [Ag 2 (tqmbp) 2 ](SbF 6 ) 2 4 is formed by elimination of quinaldine. The Au(I) compound [Au 2 (bqmpp) 2 ]PF 6 (5) is prepared as expected and shows a linear arrangement of two phosphine ligands around Au I .