Solvent induced luminescence in supramolecular heterobimetallic gold(I)-copper(I) complexes with a bidentate nitrile ligand

Heterobimetallic complexes [Cu(N=C-Cy-C-N)2][Au(C6F5)2]·0.5 Toluene (1) and [Cu(N=C-Cy- C=N)2][Au(C6F5)2]·CH2Cl2 (2) and [AuCu(C6F5)2(N=C-Cy-C=N)2]·CH2Cl2 (3) (with the same stoichiometry but different structure) have been synthesized and the crystal structure of complex 2·CH2Cl2 has been characterized through X-ray diffraction studies. The structure shows a cationic [Cu(N=C-Cy-C=N)2]+ polymer that runs parallel to the crystallographic y axis, which is formed by the copper centers and the nitrile bridging ligands, and [Au(C6F5)2]- anions that link the polymeric chain via non-classical C-H···Au hydrogen bonds. Complexes 1, 2 and 3 only differ in the solvents and the time used for their synthesis but this greatly affects their photophysical properties. Complexes 1, 2 and 3 are brightly luminescent in solid state at room temperature with lifetimes in the microseconds range. Complexes 1 and 2 display emissions arising from IL transitions while for complex 3 an emission arising from a MLCT is proposed.The D.G.I.(MEC)/FEDER (CTQ2007-67273-C02-02) project is acknowledged for financial support. M. Rodríguez Castillo thanks the C.A.R. for a grant.Peer reviewe