文摘
A new multifunctional semirigid Schiff-base ligand comprising two pyridyl (Py) and two benzimidazolyl (Bim) donor groups, 1,2-bis(1-(1-(pyridine-3-ylmethyl)benzimidazol-2-yl)ethylidene)hydrazine (L), has been synthesized, with which 10 coordination polymers of different transition metal ions, namely, {[AgL]CF3SO3·CH3OH}n (1), {[Ag2L](p-CH3C6H4SO3)2·2CH3OH}n (2), {[Hg3LCl6]·CHCl3}n (3), [HgLBr2]n (4), {[CdL(CH3CO2)2H2O]·1.5H2O}n (5), [CdLI2]n (6), {[MnL(H2O)4](ClO4)2·H2O}n (7), [MnL(p-CH3C6H4SO3)2]n (8), {[ZnL2(CH3CN)2(H2O)2](CF3SO3)2}n (9), and {[ZnL2(CH3CH2OH)2(H2O)2](p-CH3C6H4SO3)2}n (10) have been prepared and characterized by elemental analyses, IR spectroscopy, powder X-ray diffraction, and single-crystal X-ray diffraction. In complexes 1, 2, and 3, L acts as a tetradentate ligand to connect four metal ions that show the same coordination environment in 1 or different coordination environments in 2 and 3, generating two-dimensional (2D) networks of the (4, 4) net topology. In complexes 4−8, L acts as a bidentate ligand to bridge two metal ions that display diversified coordination environments depending on coordination of the anions and/or water molecules. Complexes 4−7 have similar one-dimensional (1D) chain structures, while 8 is a three-dimensional (3D) framework with dia topology. In complexes 9 and 10, L acts as a monodentate ligand to form mononuclear coordination motifs. Besides versatile coordination modes, ligand L takes on different conformations responsive to donor affinity of different metal ions. In the case that the ligand L is bidentate or monodentate, there are Py and/or Bim groups free of coordination, thus being able to form hydrogen bonds through their noncoordinating NPy or NBim atoms. Therefore, the assembly processes are directed by synergistic effects involving metal−ligand coordination, hydrogen-bonding, π···π stacking, and other influencing factors such as solvents and counteranions.