AUTHOR=Tian Xinyu , Teri Gele , Shele Muge , E Namila , Qi Liming , Liu Min , Baiyin Menghe 

TITLE=Strong Photocurrent Response of Selenoarsenates With Different Transition Metal Complexes as Structure-Directing Agents

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.890496

DOI=10.3389/fchem.2022.890496

ISSN=2296-2646

ABSTRACT=<p>Four selenoarsenates with different transition-metal complexes [Co(tren)<sub>2</sub>H]AsSe<sub>4</sub> [tren = tris(2-aminoethyl)amine] (<bold>1</bold>); [Ni<sub>2</sub>(dien)<sub>4</sub>](As<sub>2</sub>Se<sub>5</sub>) (dien = diethylenetriamine) (<bold>2</bold>); [Zn(tren)]<sub>2</sub>(As<sub>2</sub>Se<sub>5</sub>) (<bold>3</bold>) and [Mn(tren)]<sub>2</sub>(As<sub>2</sub>Se<sub>5</sub>) (<bold>4</bold>) were solvothermally synthesized in a mixed solvent of organic amine and alcohol solution. The compounds <bold>1-4</bold> have pyramidal/tetrahedral structures (AsSe<sub>3</sub>/AsSe<sub>4</sub>), and contain transition metal (Co<sup>2+</sup>, Ni<sup>2+</sup>, Zn<sup>2+</sup> and Mn<sup>2+</sup>) complex that form distinct zero-dimensional (0-D) clusters. Arsenic atoms form a tetrahedron in compounds <bold>1</bold> and <bold>2</bold>; <bold>1</bold> consists of discrete tetrahedral (AsSe<sub>4</sub>) and transition metal complex [Co(tren)<sub>2</sub>]<sup>2+</sup>; <bold>2</bold> is composed of an anion [As<sub>2</sub>Se<sub>5</sub>]<sup>4-</sup> cluster and transition metal complex [Ni(dien)<sub>2</sub>]<sup>2+</sup>. In compounds <bold>3</bold> and <bold>4</bold>, arsenic atom forms a pyramidal AsSe<sub>3</sub> and the two pyramidal AsSe<sub>3</sub> share a corner connection to form a dimer [As<sub>2</sub>Se<sub>5</sub>]<sup>4-</sup>; <bold>3</bold> is characterized as a cluster consisting of two unsaturated [Zn(tren)]<sup>2+</sup> caiton linked by a dimer (As<sub>2</sub>Se<sub>5</sub>)<sup>4-</sup> linkage; in <bold>4</bold>, unsaturated [Mn(tren)]<sup>2+</sup> caiton is linked to two trigonal-bipyramidal [Mn(tren)]Se via dimer (As<sub>2</sub>Se<sub>5</sub>)<sup>4-</sup> to form [Mn(tren)]<sub>4</sub>[As<sub>4</sub>Se<sub>10</sub>] cluster. To our knowledge, [Zn(tren)]<sub>2</sub>(As<sub>2</sub>Se<sub>5</sub>) (<bold>3</bold>) is the first zinc selenoarsenate containing the (As<sub>2</sub>Se<sub>5</sub>)<sup>4-</sup> anion type. Furthermore, the Mn<sup>2+</sup> ions adopt a trigonal-biyramidal (five-coordinate) and octahedral (six-coordinate) environment. Adding K<sub>2</sub>CO<sub>3</sub>/Cs<sub>2</sub>CO<sub>3</sub> to the synthesis system is necessary and may act as a mineralizer. Several properties of compounds <bold>1</bold>-<bold>4</bold> have been characterized in our studies, in particular their strong photocurrent response characteristics under visible light irradiation.</p>