New structural motifs, unusual quenching of the emission and second harmonic generation of Cu(I) iodide polymeric or oligomeric adducts with some para-substituted pyridines or trans-stilbazoles

The structural, emissive, and nonlinear optical properties of new Cul adducts with para-substituted trans-stilbazolic and pyridinic ligands are reported. Single-crystal X-ray diffraction results indicate that the para-substituent on the organic ligand greatly influences the structural motif by its steric (tert-butyl), electronic/steric (dimethylamino), or bridging-donor (cyano) properties so that two absolutely new structural motifs, polymeric and oligomeric, are found when trans-stilbazole and pyridine carry a dimethylamino group in the para-position. In addition, a surprising Photoemission behavior is observed, being the solid-state emission of [Cul(trans-4-stilbazole)] n, [Cul(trans-4′-(dimemylamino)-4-stilbazole)] n, and [Cul(4′-tert-butyl-4-stilbazole)] n totally quenched. In the case of the noncentrosymmetric Cul adduct of trans-4′-(dimethylamino) stilbazole a discrete second harmonic generation (SHG) occurs.