Varied Layer Topologies in Luminescent Zinc Coordination Polymers with Flexible Aromatic ortho‐Dicarboxylate and Dipyridyl Ligands

Abstract

AbstractHydrothermal synthesis has afforded four divalent zinc flexible‐arm aromatic ortho‐dicarboxylate coordination polymers containing dipyridyl coligands. According to X‐ray crystallography, all four show layered coordination polymer structures. Nevertheless there is significant ligand influence on the nature of zinc atom aggregation and overall topology. In both {[Zn2(hmph)2(dpa)2]·2H2O}n (1) (hmph = homophthalate, dpa = 4, 4′‐dipyridylamine), and {[Zn2(hmph)2(dpe)2](ClO4)2·H2dpe·4H2O}n (2) [dpe = bis(4‐pyridyl)ethane], large {Zn2(hmph)2} dimeric units are evident, along with an overall herringbone (6, 3) layer topology. The longer span of the dpe ligands results in larger incipient channels, which can accommodate protonated dpe dications and perchlorate counterions. In {[Zn2(hmph)2(3‐pna)]·H2O}n (3) (3‐pna = 3‐pyridylnicotinamide), {Zn2(OCO)2} anti‐syn bridged dimers and {Zn2(OCO)4} syn‐syn paddlewheel dimers coexist and are linked together by hmph and 3‐pna ligands into decorated (4, 4) grid coordination polymer layers. {[Zn(1, 2‐phda)(3‐pina)]·2H2O}n (4) (1, 2‐phda = 1, 2‐phenylenediacetate, 3‐pina = 3‐pyridylisonicotinamide) manifests an undulating (4, 4) grid structure with isolated zinc atoms; the “wavelength” of the layers measures over 40 Å. Luminescent properties of these materials are also reported.