Silver(I) and rhenium(I) metal complexes of a 2,2'-bipyridine-functionalized third-generation tris(pyrazolyl)methane ligand.

Heterotopic ligands offer the possibility of preparing polynuclear bimetallic complexes. Recent studies of heteroditopic ligands and their metal complexes have focused on novel supramolecular systems, biological activity, and the development of MRI contrast agents. The heteroditopic ligand Bipy-CH2 -O-CH2 -C(pz)3 (Bipy-L; Bipy is 2,2'-bipyridine and pz is pyrazolyl) reacts with AgBF4 to produce the coordination polymer catena-poly[[silver(I)-(μ-5-{[tris(pyrazol-1-yl)methoxy]methyl-κ2 N,N'}-2,2'-bipyridine-κ2 N,N')] diethyl ether hemisolvate], {[Ag(C22 H20 N8 O)]BF4 ·0.5C4 H10 O}n , and with Re(CO)5 Br to form the discrete compound bromidotricarbonyl(5-{[tris(pyrazol-1-yl)methoxy]methyl}-2,2'-bipyridine-κ2 N,N')rhenium(I), [ReBr(C22 H20 N8 O)(CO)3 ]. The silver(I) compound is a one-dimensional coordination polymer, built up by a κ2 coordination mode of the bipyridine group and a κ2 -κ0 coordination mode of the -C(pz)3 donor set. In [ReBr(Bipy-L)(CO)3 ], the ligand coordinates only via the bipyridine end, leaving the -C(pz)3 donor set free for further coordination interactions.