Structural Diversity in Zn(II) Coordination Polymers Constructed by Linear N,N’-Donor Linker and Different Pseudohalides: Sorption Study and Luminescent Properties

摘要

Reaction of a linear N,N’-donor ligand, (4-bpdh) with Zn(NO3)2·6H2O and four different pseudohalides [NCS~-, NCO~-, N3 ~- and N(CN)2 ~-]; afforded five complexes, namely {Zn(4- bpdh)(H-4-bpdh)(SCN)3]}n (1), {Zn(4-bpdh)(CNO)2]}n (2), {Zn(4- bpdh)(N3)2]}n (3), {Zn3(4-bpdh)3(N3)6(H2O)]·(4-bpdh)-(0.5) (H2O)4}n (4) and {[Zn(4-bpdh)2(N(CN)2)](N(CN)2);;x(H2O)}n (5). All the complexes 1–5 were characterized by single crystal X-ray analysis and other physicochemical methods. From X-ray structural analysis, 1 is a discrete zero dimensional monomer, extended to a one dimensional supramolecular structure by H-bonding and C-H···p interactions. Isostructural 2–3 are showing one dimensional chain structure. On the other hand, 4 shows a two dimensional structure linked by both bridging azide, and 4- bpdh, whereas 5 forms a two-fold interpenetrated a-polonium type three-dimensional network having two different types of channels occupied by the water molecule and free dicyanamide. The sorption study was performed for compound 2, 4 and 5 with different gases and vapors. Both 2 and 4 shows surface adsorption for the gases but evacuated framework of 5 selectively adsorbs CO2 over N2 and H2. Both 4 and 5 also exhibit interesting sorption behavior for the vapors. Solid state luminescence studies of all the complexes have also been performed at room temperature which shows ligand based emission in all the cases.