A Highly Efficient Near-Infrared-Activated Photocatalyst Based on an Electron-Deficient Copper-Viologen-Polyoxometalate Framework with a Copper {Cu₃} Cluster Decorated Phosphotungstate as a Building Block

Abstract

A photocatalytic active phosphotungstate cluster is incorporated into the backbone of an electron-deficient copper-viologen framework via a copper-substituted and coordination connection. Self-assembly with a bottom-up designed strategy allows functional units to be organized into an ordered arrangement [Cu2(H2O)3­(CPBPY)2­(CuHPW11O39)]·7H2O (1) that tunes the band structure and engineers the optical energy gap of the photocatalyst. Interactions between the electron-deficient host framework and the captured guest cluster strengthens the photogenerated electron–hole separation. This designed catalytic molecular system shows a high photooxidation capability toward the degradation of dye pollutants with a UV, visible, and even near-infrared light response.

An excellent multifunctional photocatalyst with a polyoxometalate–viologen framework for CEES oxidation, Cr(vi) reduction and dye decolorization under different light regimes

“…32 The absorption peak at 1663 nm originates from the phenyl C–H stretching overtone band. 21 The band gap energy ( E g ) value of BHU-1 is 2.62 eV, which reveals its potential as a semiconducting photocatalyst with a wide spectrum region (Fig. 3a).…”

“…Electron-deficient viologen ligands with photosensitivity were used to construct new kinds of POMOFs as photocatalysts to broaden their absorption spectrum from the ultraviolet to the full spectrum region, such as [Cu 2 (CPBPY) 4 (H 2 O) 2 ][PW 12 O 40 ] [OH]·6H 2 O, [Cu 2 (H 2 O) 3 (CPBPY) 2 (CuHPW 11 O 39 )]·7H 2 O, and [Cu(PBPY)] 2 [SiW 12 O 40 ]. 20–22 Combining POMs and viologen ligands within one framework would be a promising way to design efficient photocatalysts for promoting the synergy among components and utilization of sunlight in practical applications. In this work, the functionalized viologen ligand HbcbpyCl (1-(4-carboxybenzyl)-4,4′-bipyridinium chloride, Scheme 1) was combined with [Mo 8 O 26 ] 4− and Co 2+ by hydrothermal reactions, resulting in a novel 2D POM-based cobalt-framework with the viologen ligand [Co II (bcbpy) 2 (θ-Mo 8 O 26 ) 0.5 ]·5H 2 O ( BHU-1 ), which represents the first example constructed from a bcbpy ligand and POMs.…”

Heterometallic–Organic Framework from [Cu2I2] and [PbO]n Chains: Photoluminescence, Sensing, and Photocatalytic Performance

“…Generally, the practical operability, short response time, high anti-interference nature, and good recyclability make these sensing materials comparable to or even better than those traditional sensors. Moreover, the photofunctional MOFs can serve as novel luminescent thermometers, which offer a prospective platform for temperature identification with the merits of high sensitivity and noninvasiveness as well as universality in intense electric and magnetic fields. , On the other hand, numerous semiconducting MOFs are capable of acting as admirable photocatalysts for the elimination of dye molecules, as they can provide opportunities to mineralize the organic pollutants to some smaller components such as CO 2 and H 2 O. − In comparison with many traditional photoinduced catalysts which suffer from difficulty of isolation and loss of activity, the MOF-based photocatalysts with predesigned components can accomplish the degradation of dye contaminants with high efficiency and excellent recyclability. For example, the three-dimensional indium–organic framework SNNU-110 was constructed from the combination of a tritopic carboxylate ligand with an [In 3 O­(COO) 6 ] cluster, displaying excellent photocatalytic behavior toward the decomposition of methylene blue and rhodamine B .…”

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

“…The introduction of viologens, namely, N,N′-disubstituted-bipyridinium (V 2+ ) salts, can provide a new electron transport pathway, which may endow materials with interesting fluorescent and tunable photovoltaic activities in response to light and heat. − The viologen cations can be generated in situ by the reaction of 4,4′-bipyridine and alcohol or acetic acid at high temperatures, and the acidic environment of the guided synthesis of multifunctional zeolitic and inorganic open framework materials. − Previous works proved that the introduction of viologen cations into POMs can make them exhibit noticeable photo/thermochromism and electrochromism. − Consequently, the synthesis of POMs–viologen crystalline hybrids is of great significance. Notably, the POMs containing in situ generated alkyl viologen have not yet been reported.…”