Novel Oligodipyridylamine Ligands with Chiral N-Alkyl Side Chains. Synthesis of Coordination Polymers Consisting of Copper Complexes Containing the Ligands and Their Crystal Structure and Optical and Magnetic Properties

Dipyridylamine (dpa) oligomers having chiral (S)-2-methylbutyl (MB) side chains at the amine-N atoms, (MBdpa) m (H-(C 5 H 3 N-N(MB)-C 5 H 3 N) m -H; m = 2, 3, and 4), were synthesized. Complexation of (MBdpa) 2 with CuCl 2 provided a coordination polymer, [{Cu 2 Cl 4 -(MBdpa) 2 } n ]. Single-crystal X-ray analysis of [{Cu 2 Cl 4 -(MBdpa) 2 } n ] showed that intermolecular interactions linked the Cu 2 Cl 4 -(MBdpa) 2 complexes into one-dimensional coordination polymers. The crystal of [{Cu 2 Cl 4 -(MBdpa) 2 } n ] exhibited a phase transition between 100 and 85 K due to the ordering of the MB side chains, resulting in a quadrupling of the unit cell. (MBdpa) m had an expanded electron system along the oligomer main chain as revealed by UV-vis spectroscopy. (MBdpa) m were photoluminescent in solutions and copper complexation quenched their photoluminescence.