Narrow‐Bandgap Chalcogenoviologens for Electrochromism and Visible‐Light‐Driven Hydrogen Evolution

Abstract

As eries of electron-accepting chalcogen-bridged viologens with narrowH OMO-LUMO bandgaps and low LUMO levels is reported. The optoelectronic properties of chalcogenoviologens can be readily tuned through heavy atom substitution (S,S ea nd Te). Herein, in situ electrochemical spectroscopyw as performed on the proof-of-concept electrochromic devices (ECD). E-BnV 2+ (E = Se,T e; BnV 2+ = benzyl viologen) was used for the visible-light-driven hydrogen evolution due to the strong visible-light absorption. Remarkably,E-BnV 2+ was not only used as aphotosensitizer,but also as an electron mediator,p roviding an ew strategy to explore photocatalysts.T he higher apparent quantum yield of Se-BnV 2+ could be interpreted in terms of different energy levels, faster electron-transfer rates and faster formation of radical species.The research and application of viologen analogs (RV 2+ ) have developed rapidly, [1] particularly in fields such as electrochromic display devices (ECD), [2] metallosupramolecular assemblies, [3] host-guest complexes, [4] solar-to-fuel conversion, [5] energy storage [6] and many other applications. [7] The widespread use of viologen analogs results from their unique properties,that is,different redox states of these analogs can donate or accept electrons,p articipate in the coordination from reversible redox reaction and change color between purple and orange. [8]

Asymmetric Heteroleptic Ir(III) Phosphorescent Complexes with Aromatic Selenide and Selenophene Groups: Synthesis and Photophysical, Electrochemical, and Electrophosphorescent Behaviors

“…The bond lengths in the selenophene units for Ir-Se2F and Ir-Se3F are ca. 1.86 Å, similar to the reported data, while those in the thiophene and tellurophene units are 1.73 and 2.10 Å, respectively.…”

“…The C–Se–C bond angles in the aryl selenophene units are 86.2(4)° for Ir-Se2F and 85.6(3)° for Ir-Se3F , similar to the reported data . In their analogous scaffolds with thiophene and tellurophene units, the C–S–C bond angles in thiophene units and C–Te–C bond angles in tellurophene units are ca. 90 and 80°, respectively.…”

“…120°) bond angles are larger than that of C–Se–C in the aryl selenide units of these asymmetric heteroleptic Ir­(III) complexes . The C–Se–C bond angles in the aryl selenophene units are 86.2(4)° for Ir-Se2F and 85.6(3)° for Ir-Se3F , similar to the reported data . In their analogous scaffolds with thiophene and tellurophene units, the C–S–C bond angles in thiophene units and C–Te–C bond angles in tellurophene units are ca.…”

Photochromic Semiconductive Hydrogen-Bonded Organic Framework (HOF) with Broadband Absorption

“…They are widely used in gas storage and separation, chemical sensing, catalysis, biomedicine, and optoelectronic materials − because of many advantages such as easy synthesis, easy to make film, and good flexibility. The positive photochromic behavior of viologen compounds − has been widely studied because of the obvious redshift of absorption bands after photoinduced electron transfer. We have previously found that infinite π-stacking of viologen cations is an effective approach to synthesize photochromic semiconductors. , Therefore, it is possible to use viologen units to prepare photochromic semiconductive HOFs with broadband photoelectric response through a careful design of hydrogen-bonding networks.…”

A tellura-Baeyer–Villiger oxidation: one-step transformation of tellurophene into chiral tellurinate lactone

“…[12][13][14][15][16][17] The emerging development of tellurium compounds is apparent from the applications in catalysis, [18][19][20][21] coordination, [22][23][24][25][26] and optoelectronic materials. [27][28][29][30][31][32][33][34] The low Pauling electronegativity and high polarisability of tellurium lead to strong secondary bonding interactions (SBIs) and/or hypervalent states. 12,[35][36][37][38] Meanwhile, embedding Te onto the π-scaffolds of organotellurium compounds will narrow HOMO-LUMO energy gap, [39][40][41][42] produce intermolecular Te•••X SBIs in solid state, [43][44][45] and alter the chemical behaviors.…”