Zinc(ii) nitrite coordination polymers based on rigid and flexible organic nitrogen donor ligands

Abstract

Six zinc(II)-organic coordination polymers, [Zn(μ-4,4′-bipy)(NO₂)₂]_n (1), [Zn(μ-bpa)(NO₂)₂]_n (2), [Zn(μ-bpe)(NO₂)₂]_n (3), [Zn(μ-bpp)(NO₂)₂]_n (4), [Zn(μ-4-bpdb)(NO₂)₂]_n (5) and {[Zn₂(μ-3-bpdb)₂(NO₂)₄]·H₂O}_n (6) {4,4′-bipy = 4,4′-bipyridine, bpa = 1,2-bis(4-pyridyl)ethane, bpe = 1,2-bis(4-pyridyl)ethene and bpp = 1,3-di(4-pyridyl)propane, 4-bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and 3-bpdb = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene}, were prepared from reactions of zinc(II) nitrite with six rigid and flexible organic nitrogen donor-based ligands. All these compounds were structurally characterized by X-ray single-crystal diffraction and the structural studies of compounds 1–6 show the compounds are 1-D polymers with distorted octahedral ZnN₂O₄ coordination environments. The thermal stabilities of compounds 1–6 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). Solution state luminescent spectra of compounds 1, 2 and 4 indicate intense fluorescent emissions at ca. 347, 360 and 370 nm, respectively.