Syntheses, crystal structures and luminescence properties of two copper(II) complexes with terpyridine and dicarboxylate ligands

Two coordination complexes [Cu(phtpy)(obda)]·2H2O (1) and [Cu4(meophtpy)4(mbda)4]·4H2O (2) [phtpy = 4′-phenyl-2,2′:6′,2″-terpyridine, meophtpy = 4′-(4-methoxyphenyl)-2,2′:6′,2″-terpyridine, H2obda = 1,2-benzenedicarboxylic acid and H2mbda = 1,3-benzenedicarboxylic acid] have been synthesized under hydrothermal conditions and characterized by IR, elemental analysis and X-ray single-crystal diffraction. In complex 1, the Cu(II) atoms are bridged by obda2− ligands to give 1D chains with phtpy as a terminal ligand, while a 3D network is constructed by hydrogen bonds and π–π interactions. In complex 2, the Cu(II) atoms are coordinated by two meophtpy ligands and also linked by mbda2− ligands forming a discrete tetranuclear complex. In this complex also, a 3D network is constructed by hydrogen bonds and π–π interactions. The most striking feature of complex 2 is that one meophtpy ligand is almost overlapped upon the next which is seldom found in 2,2′:6′,2″-terpyridine complexes. The luminescence properties of both complexes 1 and 2 have been investigated.