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摘要
The new copper dimer [LCu(DMF)](2)(NO3)(4)(H2O)(DMF)(2) (4), where L = [{1,1'-(CH2)(2)-C14H8)-3,3'-(CH2CO2)(2)}{( HCN)(2)CH}], and porous coordination polymers [{L2Cu(OH2)(2)}(2)Br-2](x) (5)and [{L2Zn(OH2)(2)}(2)Br-2](x) (6)have been isolated from reactions of luminescent imidazolium carboxylate ligand, LH2Br2 (3)and the corresponding metal precursors. The reaction between Cu(NO3)(2)center dot 3H(2)O and LH2Br2 (3)in DMF at 100 degrees C yielded bluish green crystals of tetracationic discrete copper dimer 4, the structure of which contains a rare tetracationic [(DMF)Cu(II)](2) dimer unit that is bridged by four carboxylates of two L in a " paddle-wheel" structure. When the reaction was carried out in the presence of a water-ethanol-methanol mixture, light green crystals of 5 were obtained. Molecule 5 comprises two-dimensional (2D)porous coordination polymeric sheets consisting of unique symmetrical dinuclear [(C(O)O)Cu(OH2)(2)(O(O)C)(2)](2) building blocks, which are connected by imidazolium anthracene spacers. The infinite 2D porous coordination polymeric sheets are further linked by significant intermolecular hydrogen-bonding interactions by bromide anions to form a three-dimensional supramolecular framework. Interestingly, the reaction between zinc dust and LH2Br2 (3)in H2O at room temperature gave similar structural features to those in 5, though they differ in terms of C-O bond distances and M-O-C angles. The solution-state UV-visible absorption spectra of 2-6 in water exhibits the comparable absorption pattern with decrease in the intensity of absorption from 5, 4, 3, 6 and 2, while the solid-state UV-visible absorption spectra of 2-6 are significantly different from the solution-state UV-visible absorption spectra. The considerable change in the fluorescent emission was observed upon complexation of 3 with corresponding metal precursors and the fluorescent emission was shifted towards the red region in the order of 2, 3, 6, 4 and 5 in water.
- 出版日期2013
