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).