Zinc(ii) coordination polymers of tetrakis(4-pyridyl)cyclobutane and various dicarboxylates: Syntheses, structures and luminescent properties

Abstract

Reactions of Zn(NO₃)₂ with tetrakis(4-pyridyl)cyclobutane (tpcb) and 1,4-benzenedicarboxylic acid (1,4-H₂BDC), 4,4′-biphenyldicarboxylic acid (4,4′-H₂BPDB), 5-methyl-1,3-benzenedicarboxylic acid (5-CH₃-1,3-H₂BDC), 1,3,5-benzenetricarboxylic acid (1,3,5-H₃BTC), 5-amino-1,3-benzenedicarboxylic acid (5-NH₂-1,3-H₂BDC), 4,4′-benzophenonedicarboxylic acid (4,4′-H₂BPNDB) under solvothermal conditions led to the formation of six polydimensional coordination polymers {[Zn₅(1,4-BDC)₅(tpcb)_2.5]·5H₂O}_n (1), {[Zn₂(4,4′-BPDB)₂(tpcb)]·0.5MeCN}_n (2), [Zn₂(OH₂)₂(5-CH₃-1,3-BDC)₂(tpcb)]_n (3), {[Zn₂(1,3,5-HBTC)₂(tpcb)]·H₂O}_n (4), {[Zn₂(5-NH₂-1,3-BDC)₂(tpcb)·H₂O]}_n (5), and [Zn₂(4,4′-BPNDB)₂(tpcb)]_n (6). Compounds 1–6 were characterized by elemental analysis, IR, powder X-ray diffraction, and single crystal X-ray diffraction. Compounds 1 and 6 have different 3D (4,4) connected structures. Compounds 2–4 have different two-fold interpenetrating 3D (4,4)-connected structures. Compound 5 holds a 2D (3,4)-connected structure. The solid state luminescent properties of compounds 1–6 at ambient temperature were also investigated. The results provided some interesting insights into ligand effects on the structures and luminescent properties of zinc(II) coordination polymers.