Structural diversity and photoluminescence properties of zinc coordination polymers constructed from 1,4-bis[2-(4-pyridyl)ethenyl]-2,3,5,6-tetramethylbenzene and para-dicarboxylates

Abstract

Five new coordination networks, formulated as [Zn(1,4-BDC)(1,4-bpetmb)]_n (1), [Zn₂(1,4-CDC)₂(1,4-bpetmb)₂]_n (2), {[Zn(4,4′-BPDC)(1,4-bpetmb)_0.5]·0.25MeCN}_n (3), [Zn(4,4′-OBBC)(1,4-bpetmb)_0.5]_n (4) and {[Zn(4,4′-CDBC)(1,4-bpetmb)]·0.5C₆H₁₂} (5), have been synthesized under solvothermal conditions, based on the dipyridyl linker 1,4-bis[2-(4-pyridyl)ethenyl]-2,3,5,6-tetramethylbenzene (1,4-bpetmb) along with 1,4-benzenedicarboxylic acid (1,4-H₂BDC), 1,4-cyclohexanedicarboxylic acid (1,4-H₂CDC), 4,4′-biphenyldicarboxylic acid (4,4′-H₂BPDC), 4,4′-oxybisbenzoic acid (4,4′-H₂OBBC) and 4,4′-carbonyldibenzoic acid (4,4′-H₂CDBC), respectively. Compounds 1–5 have been structurally characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction analysis. 1 represents a sixfold interpenetrating 6⁶ diamondoid framework. 2 reveals a 3D twofold interpenetrating pcu network with point symbol 4¹²6³. 3 comprises a 3D fourfold interpenetrating 6-connected architecture with 4¹²6³ u topology. 4 exhibits a 3D threefold interpenetrating 6-connected framework with an unprecedented Schläfli symbol 5⁵6¹⁰. 5 displays a highly undulating 2D (4,4) net. A systematic structural comparison of these coordination polymers shows that the frameworks can be tuned by various para-dicarboxylates coligands. The thermal stability and photoluminescence properties of 1–5 in the solid state have also been investigated.