pH-dependent solvothermal formation of two different 3D multiple interpenetrating nets from the same components of Zn(NO3)2, 1,3-benzenedicarboxylate and 1,4-bis[2-(4-pyridyl)ethenyl]benzene

Hydrothermal reactions of Zn(NO3)(2)center dot 6H(2)O with 1,3-benzenedicarboxylic acid (1,3-H2BDC) and 1,4-bis[2-(4-pyridyl)ethenyl]benzene (1,4-bpeb) under pH 2.5 or 8.0 gave rise to two coordination polymers {[Zn-6(mu-OH2)(1,3-BDC)(6)(1,4-bpeb)(4)]center dot MeCN}(n) (1) and {[Zn-8(1,3-BDC)(8)(1,4-bpeb)4]center dot 2H(2)O}(n) (2). Both compounds were characterized by elemental analysis, IR, powder X-ray diffraction, and single-crystal X-ray diffraction. Compound 1 has two types of dinuclear zinc cores as nodes and displays an intriguing three-dimensional (3D) three-fold interpenetrating (4,6)-connected network with an unprecedented (3(2)6(4))(3(2)4(4)6(8)7)(2) topology. Compound 2 exhibits an unusual 3D twofold interpenetrating pcu net with a Schlafli symbol 4(12)6(3). The formation of 1 and 2 provided an interesting insight into the effect of pH values on the construction of coordination polymers under solvothermal conditions. Thermal stability and photoluminescence properties of 1 and 2 were also investigated.