RESUMEN
A porous Zn(ii)-coordination polymer, namely {[Zn2(µ8-abtc)(betib)]·DMF}n (1), was solvothermally synthesized from 3,3',5,5'-azobenzenetetracarboxylate (abtc4-) and 1,4-bis(2-ethylimidazol-1-yl)butane (betib) ligands and {[Zn2(µ8-abtc)(betib)]·H2O}n (2) was obtained through the immersion of 1 in methanol. Compounds 1 and 2 were structurally characterized via numerous techniques. Both compounds displayed a 3D porous framework with a 3,6-connected sqc5381 net. Compound 2a obtained at 140 °C from 2 exhibited gas and iodine adsorption properties. Interestingly, the compound adsorbed selectively CO2 with the uptake capacity of 54.02 cm3 g-1 (13.26%) over N2 (5.43 cm3 g-1) and CH4 (14.53 cm3 g-1) at 273 K. The compound also adsorbed iodine with the weights of 19.99% and 30.26% in solution and vapor phases, respectively. The single crystal X-ray result and Raman spectra showed the presence of iodine units in the pores of the framework.
RESUMEN
Four new Zn(II)-coordination polymers, namely, [Zn2(µ6-ao2btc)(µ-obix)2]n (1), [Zn2(µ4-ao2btc)(µ-obix)2]n (2), [Zn2(µ4-ao2btc)(µ-mbix)2]n (3), and {[Zn2(µ4-ao2btc)(µ-pbix)2] · 2DMF · 8H2O}n (4), where ao2btc = dioxygenated form of 3,3',5,5'-azobenzenetetracarboxylate and obix, mbix, and pbix = 1,2-, 1,3-, and 1,4-bis(imidazol-1-ylmethyl)benzene, have been synthesized with azobenzenetetracarboxylic acid and isomeric bis(imidazole) ligands and characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, powder X-ray diffraction, and thermal analyses. X-ray results showed that 1, 2, and 4 had two-dimensional structures with 3,4L13 topology, while 3 was a three-dimensional coordination polymer with bbf topology. For 4, two types of activation strategies, solvent exchange + heating (which produced 4a) and direct heating (which produced 4b), were used to investigate the effect of a guest molecule in a flexible framework. Gas adsorption and iodine encapsulation properties of activated complexes were studied. The CO2 uptake capacities for 4a and 4b were 3.62% and 9.50%, respectively, and Langmuir surface areas calculated from CO2 isotherms were 167.4 and 350.7 m(2)/g, respectively. Moreover, 4b exhibited 19.65% and 15.27% iodine uptake in vapor phase and cyclohexane solution, respectively, which corresponded to 1.47 and 0.97 molecules of iodine/formula unit, respectively. Moreover, photoluminescence properties of the complexes were studied.
RESUMEN
Two new coordination complexes, namely, [Cu(tdp)(H2O)(bim)3]·4H2O (1) and {[Cu(µ2-tdp)(bim)2]·4H2O}n (2) (tdp = 3,3'-thiodipropionate, bim = benzimidazole), having naked-eye sensor properties and thermochromic behaviors, were synthesized and structurally characterized using elemental analysis, IR and UV spectra, and single-crystal X-ray diffraction, powder X-ray diffraction (PXRD) and thermal analyses (TG, DTA and DTG) techniques. Complex 1 changed color from blue to dark and light green in methanol and DMF solvents, respectively, while complex 2 changed color from light blue to light green only in DMF solvent. Moreover, complex 1 can be used to detect as little as 10 percent methanol in ethanol by the naked eye. The thermochromic properties of the complexes showed that complexes 1 and 2 changed color from blue and light blue to light and dark green at 65 °C, respectively.