Supramolecular Arrangement Built from Zinc and Cadmium Complexes with 4′-(4-Substituted)-2,2′:6′,2″-Terpyridine: Crystallographic Investigation, Luminescence and Thermal Properties

The reaction of Zn(NO 3 ) 2 ⋅6H 2 O with tpyOH or ftpy in the presence of KSCN affords the new zinc(II) complexes [Zn(tpyOH)(NCS) 2 ] ( 1 ) and [Zn(ftpy)(NCS) 2 ] ( 2 ) while two isostructural compound of [Zn(tpyOH)(NCS) 2 ].DMSO ( 1 .DMSO) and [Zn(ftpy)(NCS) 2 ].DMSO ( 2 .DMSO) were obtained during the crystallization in DMSO, respectively. Structurally, 1 .DMSO and 2 .DMSO reveal that the Zn(II) is penta-coordinated by two nitrogen atoms of NCS − and three nitrogen atoms from tpyOH or ftpy in a highly distorted square pyramidal geometry. Interestingly, 1 .DMSO contains four crystallographically independent molecules, each of them is hydrogen-bonded to DMSO and adopts supramolecular structure constructed by OH…O hydrogen bonds. On the other hand, the reaction of CdCl 2 with ftpy has been resulted in the formation of the new distorted square pyramid complex [Cd(ftpy)Cl 2 ] ( 3 ). The crystal structure of 3 is stabilized by the extensive hydrogen bonds of C–H…Cl between H atoms of ftpy and the Cl atoms. Crystal structures of 2 .DMSO and 3 reveal that these porous materials have voids, occupied by the solvents. The volume of voids in 2 .DMSO and 3 are 542 and 555 Å 3 , respectively. Hirshfeld surface analysis were used to identify and quantify the inter-molecular interactions such as H-bonds and π-stackings. Thermogravimetric and differential thermal analysis showed that three compounds possess great thermal stabilities, especially for 2 which is stable up to 373 °C. The luminescent properties of compounds were assigned to π–π* transitions.