Structural variations and spectroscopic properties of copper(I) complexes with bis(schiff base) ligands

Six copper(I) complexes {[Cu-2(L1)(PPh3)(2)I-2]center dot 2CH(2)Cl(2)}(n) (1), {[Cu-2(L2)(PPh3)(2)]BF4}(n) (2), [Cu-2(L3)(PPh3)(4)I-2]center dot 2CH(2)Cl(2) (3), [Cu-2(L4)(PPh3)(4)I-2] (4), [Cu-2(L5)(PPh3)(2)I-2] (5) and [Cu-2(L6)(PPh3)(2)I-2] (6) have been prepared by reactions of bis(schiff base) ligands: pyridine-4-carbaldehyde azine (L1), 1,2-bis(4'-pyridylmethyleneamino)ethane (L2), pyridine-3-cat-baldehyde azine (L3), 1,2-bis(3'-pyridylmethyleneamino)ethane (1,4), pyridine-2-carbaldehyde azine (L5), 1,2-bis(2'-pyridylmethyleneamino)ethane (1.6) with PPh3 and copper(I) salt, respectively. Ligand L1 or L2 links (PPh3)(2)Cu-2(mu-I)(2) units to form an infinite coordination polymer chain. Ligand 3 or 4 acts as a monodentate ligand to coordinate two copper(I) atoms yielding a dimer. Ligand 5 or 6 chelates two copper(I) atoms using pyridyl nitrogen and imine nitrogen to form a dimer. Complexes 1-4 exhibit photoluminescence in the solid state at room temperature. The emission has been attributed to be intraligand pi-pi* transition mixed with MLCT characters. (c) 2005 Elsevier B.V. All rights reserved.