Assembly and photocatalysis of two novel 3D Anderson-type polyoxometalate-based metal–organic frameworks constructed from isomeric bis(pyridylformyl)piperazine ligands

Abstract

Two novel Anderson-type polyoxometalates (POMs)-based metal-organic frameworks (MOFs), namely, H{Cu2(μ2-OH)2L(1)[CrMo6(OH)6O18]}·4H2O (), {Cu2L(2)[CrMo(VI)5Mo(V)(OH)6O18](H2O)4}·4H2O () (L(1) = N,N'-bis(3-pyridinecarboxamide)-piperazine, L(2) = N,N'-bis(4-pyridinecarboxamide)-piperazine), are hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectra, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). In complex , the hexadentate [CrMo6(OH)6O18](3-) polyoxoanion bridges the Cu(II) ions to generate a 2D Cu-POM inorganic layer, which is further extended by the μ2-bridging L(1) ligands (via ligation of pyridyl nitrogen atoms) to form a 3D MOF with a 4,6-connected {4(4)·6(10)·8}{4(4)·6(2)} topology. Complex is also a 3D POM-based MOF exhibiting a {4(2)·8(4)} topology, which is constructed from the quadridentate [CrMo(VI)5Mo(V)(OH)6O18](4-) polyoxoanions and μ4-bridging L(2) ligands (via ligation of pyridyl nitrogen and carbonyl oxygen atoms). The different coordination modes of POM polyanions and the isomeric bis(pyridylformyl)piperazine ligands play key roles in the construction of the title complexes. In addition, the photocatalytic activities of the title complexes on the degradation of methylene blue (MB) under UV, visible light and sunlight irradiation have been investigated in detail.

Novel polyoxometalate@g-C3N4 hybrid photocatalysts for degradation of dyes and phenolics

“…[24] It was reported that POMs are not only strong photo-oxidizing compounds but also strong Brønsted acid, so the biomass can be oxidized by POMs in solution under solar irradiation. [25] A variety of supported POMs, such as POMs/TiO 2 [26], POMs/MOFs [27], carbon quantum dots/silver nanoparticles/POMs [28], and POMs/organosilca frameworks [29], have been prepared for photocatalytic reactions. It would be very interesting to incorporate POMs onto the emerging 2D-structured, metal-free, visible light photocatalyst of g-C 3 N 4 , however, no such materials have been synthesized and tested for photodegradation of phenolics and dyes.…”

Synthesis, dynamic NMR characterization and XRD studies of novel N,N’-substituted piperazines for bioorthogonal labeling

“…Functionalized piperazines [5], especially benzoylated derivatives, are our interest. In the past, mono or bisacylated piperazines with benzamide [6], nicotinamide [7] and isonicotinamide [8–11] residue were explored in terms of their NMR and complexation behavior. However, unsymmetrically substituted piperazines are rarely investigated [12–13].…”

Degradation of hazardous organic dyes with solar‐driven advanced oxidation process catalyzed by the mixed metal–organic frameworks

“…[42] As shown in Figure 10a, in the fluorescence spectra of the solution containing the catalytic STA-12(Fe, Mn)/sunlight/H 2 O 2 system and NaTA, peak intensity increases sharply to 930 within 10 min, [(AgL)(CF 3 SO 3 )]n -NS/7980 90 [23] H[Cu 2 (μ 2 -OH) 2 L 1 (CrMo 6 (OH) 6 O 18 )]·4H 2 O -SS/780 87 [48] [Cu 2 L 2 (CrMo 6 (OH) 6 [49] UiO-66(1.25Ti) 10 and 1000 SS/80 82 [50] [(CH 3 ) 2 NH 2 ] . [42] As shown in Figure 10a, in the fluorescence spectra of the solution containing the catalytic STA-12(Fe, Mn)/sunlight/H 2 O 2 system and NaTA, peak intensity increases sharply to 930 within 10 min, [(AgL)(CF 3 SO 3 )]n -NS/7980 90 [23] H[Cu 2 (μ 2 -OH) 2 L 1 (CrMo 6 (OH) 6 O 18 )]·4H 2 O -SS/780 87 [48] [Cu 2 L 2 (CrMo 6 (OH) 6 [49] UiO-66(1.25Ti) 10 and 1000 SS/80 82 [50] [(CH 3 ) 2 NH 2 ] .…”

“…• , therefore it could be used as a selective probe in sensing • OH radicals. [42] As shown in Figure 10a, in the fluorescence spectra of the solution containing the catalytic STA-12(Fe, Mn)/sunlight/H 2 O 2 system and NaTA, peak intensity increases sharply to 930 within 10 min, [(AgL)(CF 3 SO 3 )]n -NS/7980 90 [23] H[Cu 2 (μ 2 -OH) 2 L 1 (CrMo 6 (OH) 6 O 18 )]·4H 2 O -SS/780 87 [48] [Cu 2 L 2 (CrMo 6 (OH) 6 [49] UiO-66(1.25Ti) 10 and 1000 SS/80 82 [50] [(CH 3 ) 2 NH 2 ] . [Cu 2 (CN) 3 ] 3.7 and 100 NS/1440 91 [24] STA-12(Fe, Mn) indicating that • OH radicals were truly produced in the system.…”