A Co-MOF with a (4,4)-connected binodal two-dimensional topology: synthesis, structure and photocatalytic properties

Abstract

The Co-MOF poly[[diaqua{μ4-1,1,2,2-tetrakis[4-(1H-1,2,4-triazol-1-yl)phenyl]ethylene-κ4 N:N′:N′′:N′′′}cobalt(II)] benzene-1,4-dicarboxylic acid benzene-1,4-dicarboxylate], {[Co(C34H24N12)(H2O)2](C8H4O4)·C8H6O4} n or {[Co(ttpe)(H2O)2](bdc)·(1,4-H2bdc)} n , (I), was synthesized by the hydrothermal method using 1,1,2,2-tetrakis[4-(1H-1,2,4-triazol-1-yl)phenyl]ethylene (ttpe), benzene-1,4-dicarboxylic acid (1,4-H2bdc) and Co(NO3)2·6H2O, and characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction (PXRD), luminescence, optical band gap and valence band X-ray photoelectron spectroscopy (VB XPS). Co-MOF (I) shows a (4,4)-connected binodal two-dimensional topology with a point symbol of {44·62}{44·62}. The two-dimensional networks capture free neutral 1,4-H2bdc molecules and bdc2− anions, and construct a three-dimensional supramolecular architecture via hydrogen-bond interactions. MOF (I) is a good photocatalyst for the degradation of methylene blue and rhodamine B under visible-light irradiation and can be reused at least five times.

New Transition Metal Coordination Polymers Derived from 2-(3,5-Dicarboxyphenyl)-6-carboxybenzimidazole as Photocatalysts for Dye and Antibiotic Decomposition

“…In addition, like DTZ photodecomposition, the photodegradation of RhB also followed pseudo-first-order kinetics (Figure 6d), and the rate constants for all three CPs calculated by using the plot of ln(Ct/C0) vs. time (Table 1) suggested that the rate constant k (min −1 ) for RhB degradation was highest in the presence of CP 2. Hence, the percentage photodegradation of RhB and the rate constant parameters further suggested that amongst all three CPs, Mn(II) CP 2 displayed the best photocatalytic efficiency, which might be because of the variation in the structural environments around the metal centers [77][78][79]. Furthermore, for RhB photodegradation, 2 radical scavenging experiments in the presence of a photocatalyst were performed [80][81][82][83][84][85][86][87][88][89] (Figure 7).…”

“…Hence, the percentage photodegradation of DTZ and the rate constant parameters further suggested that amongst all three CPs, the Mn(II) CP 2 displayed the best photocatalytic efficiency. These differences in the catalytic activities of the CPs might be arising because of the variation in the structural environments around metal centers [77][78][79]. Moreover, to assess the nature of possible active species generated in situ that are responsible for the photodecomposition of DTZ in the presence of photocatalyst 2, radical scavenging experiments were performed.…”