Three-Dimensional Interpenetrating Frameworks Based on {P₄Mo₆} Tetrameric Clusters and Filled with In Situ Generated Alkyl Viologens

Abstract

HPO 4 ) 3 (PO 4 )-(OH) 3 ) 4 ]•8H 2 O (3, 4) (TM = Co 2+ (1, 3), Mn 2+ (2, 4)) were synthesized and characterized using infrared spectroscopy, elemental analyses, thermogravimetric analysis, and single-crystal X-ray diffraction. In situ generated methyl viologen (compounds 1 and 2) or ethyl viologen (compounds 3 and 4) cations function as templates to induce the generation of 2-fold interpenetrating structures in which the {P 4 Mo 6 } tetrameric clusters with [TM 4 (PO 4 )Na 6 ] (TM = Co 2+ (1, 3) and Mn 2+ (2, 4)) as the core were bridged by transition metal ions. Compounds 1−4 possess high thermal stabilities and the decomposition temperature of the inorganic frameworks were all >500 °C. It is worth noting that the four compounds all exhibited the bifunctional catalytic performance that they not only had an excellent photocatalytic activity for the reduction of hexavalent chromium (Cr(VI)) under visible light irradiation but also showed a good electrocatalytic activity for the reduction reaction of hydrogen peroxide.

Cobalt complexes tuned by Anderson-type polyoxometalates and bis-amide derivative ligands featuring a ‘V’-like connector for efficient ampere sensing and the visible-light catalytic reduction of Cr(vi)

“…Photocatalytic reduction has become an effective way to remove heavy metal Cr( vi ) ions. 46 The light-harvesting capacities of complexes 1–4 were first analyzed by UV–vis DRS. As shown in Fig.…”

A Purely Inorganic Quasi‐Keggin Polyoxometalate for Photocatalytic Conversion of Carbon Dioxide to Carbon Monoxide

“…Note that the bond angle of P−O−Co is 180°, which enables {Co 2 PO 4 } to form the larger tetrahedron (Figure 1d and S7). On the other hand, four {Co[P 4 Mo 6 ]} units distributed regularly around the periphery of the inner core to form an outer shell, wrapping the {Co 2 PO 4 } tetrahedron by linkage of μ 2 ‐O atoms (Figure 1e and 1 f), which is quite distinguished from the twisted tetramer based on {P 4 Mo 6 } clusters [38–40] . These Co(1) atoms serving as important nodes encounter with the four adjacent {Co[P 4 Mo 6 ]} units, giving rise to the Keggin‐like shape (Figure 1f).…”

“…On the other hand, four {Co[P 4 Mo 6 ]} units distributed regularly around the periphery of the inner core to form an outer shell, wrapping the {Co 2 PO 4 } tetrahedron by linkage of μ 2 -O atoms (Figure 1e and 1 f), which is quite distinguished from the twisted tetramer based on {P 4 Mo 6 } clusters. [38][39][40] These Co(1) atoms serving as important nodes encounter with the four adjacent {Co[P 4 Mo 6 ]} units, giving rise to the Keggin-like shape (Figure 1f). Moreover, four half-site-occupied Na cations are grafted on the surface of macroanion cluster to balance the negative charge of the framework (Figure S10 S12).…”

Efficient visible-light-driven reduction of hexavalent chromium catalyzed by conjugated organic species modified hourglass-type phosphomolybdate hybrids

“…[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] As a peculiar member of the POM family, hourglass-type reduced phosphomolybdate {M(P 4 12− subunits bridged by one metal (M) center has been considered as a promising candidate for heterogeneous photocatalytic Cr(VI) reduction owing to its specific electronic structure and photochemical properties. [40][41][42][43][44] Notably, all the Mo atoms of M{P 4 Mo 6 } 2 are in +5 oxidation state, belonging to typical heteropolyblue, which endows M{P 4 Mo 6 } 2 with reversible redox capacity and a wider spectral absorption range covering visible and near infrared light regions. [45][46][47] Moreover, the low oxidation of Mo atoms also provide M{P 4 Mo 6 } 2 with high reducibility, 48 which is beneficial for photocatalytic Cr(VI) reduction.…”