Syntheses, crystal structures and photoluminescent properties of dinuclear and tetranuclear zinc complexes with 1,4-bis(2,2':6',2″-terpyridine-4'-yl)benzene

Abstract

Two zinc complexes, [(HCOO)2Zn(μ-bteb)Zn(OOCH)2]·2H2O (1) and {[(HCOO)Zn(μ-bteb)Zn(OOCH)]2(μ-O)2}·DMF·6H2O (DMF = dimethylformamide) (2), containing a π-conjugated “back to back” bis-terpyridine ligand 1,4-bis(2,2':6',2''-terpyridin-4'-yl)benzene (bteb) have been solvothermally synthesized and characterized via elemental analysis, infrared spectroscopy, thermogravimetric analysis, single-crystal X-ray diffraction, and powder X-ray diffraction. 1 and 2 are dumbbell-like dinuclear and rectangle tetranuclear ZnII complexes, respectively. It is interesting that these complexes were synthesized by adjusting the ratio of DMF and H2O. The X-ray crystal structure reveals that ZnII metal centers in 1 are five-coordinate by three nitrogens from bteb and two oxygens from monodentate formate ions, while ZnII metal centers in 2 are five-coordinate containing three nitrogens from bteb, one oxygen from a monodentate formate and the other one from a bridging O. Hirshfeld surface analyses and 2-D fingerprint plots display that the main interactions are O···H/H···O and H···H intermolecular interactions in 1 and 2. The thermal decomposition behaviors of 1 and 2 were studied by using thermogravimetric analysis. UV-Vis absorption and photoluminescent properties of 1 and 2 were also investigated.