Unprecedented 3D and 2D Frameworks of Manganese Thioarsenates Based on Heterometallic Cubic Cluster [Mn₆(µ₆‐S)(AsS₃)₄] and Covalent Linker N₂H₄

Abstract

New Mn thioarsenates [Mn(dien)2][Mn6(µ6‐S)(µ‐N2H4)3(µ3‐AsS3)4]·H2O (1) and [Mn(1,2‐dap)3][Mn6(µ6‐S)(N2H4)2(µ‐N2H4)2(µ3‐AsS3)4] (2) (dien = diethylenetriamine; 1,2‐dap = 1,2‐diaminopropane) were solvothermally synthesized with the synergistic assistance of coordinative polyamines and hydrazine. Compounds 1 and 2 contain a 3D {[Mn6(µ6‐S)(µ‐N2H4)3(µ3‐AsS3)4]2–}⋡ network and a 2D {[Mn6(µ6‐S)(N2H4)2(µ‐N2H4)2(µ3‐AsS3)4]2–}⋡ layer, respectively, which are constructed by cubic [Mn6(µ6‐S)(µ3‐AsS3)4] clusters and µ‐N2H4 covalent linkers. In the [Mn6(µ6‐S)(µ3‐AsS3)4] cluster, four As3+ cations occupy the four opposite vertexes, and six Mn2+ cations are located at the face centers. An S2– anion at the heart of the cube coordinates to six Mn2+ cations at the face center in a µ6‐S mode, generating an octahedral Mn6(µ6‐S) core. The Mn6(µ6‐S) core and µ6‐S coordination mode are observed for the first time in the Mn/As/S system. In 1, the cubic [Mn6As4S13] clusters are connected into a 3D framework of {[Mn6(µ6‐S)(µ‐N2H4)3(µ3‐AsS3)4]2–}⋡ anions through three µ‐N2H4 bridging ligands. In 2, the [Mn6As4S13] cluster is joined by two µ‐N2H4 bridging ligands and coordinated by two terminal N2H4 molecules, with formation of a 2D layer {[Mn6(µ6‐S)(N2H4)2(µ‐N2H4)2(µ3‐AsS3)4]2–}⋡. The room‐temperature band gaps of 1 and 2 are 2.21 and 2.34 eV, respectively.

Crystalline chalcogenidometalate-based compounds from uncommon reaction media

“…Hence, hydrazine proved to be a suitable reaction medium for the solvothermal synthesis of sulfidoarsenate networks. 115,116 Quaternary sulfidoantimonates(III) were synthesized by a hydrazinehydrothermal reaction at low temperature. BaAgSbS 3 and BaAgSbS 3 ÁH 2 O, despite possessing the same stoichiometry (except for the additional H 2 O molecule per formula unit in the latter) exhibit different structures.…”

Hydrazine-solvothermal methods to synthesize polymeric thioarsenates from one-dimensional chains to a three-dimensional framework

“…Inspired by our previous work on fabrication of TM-containing chalcogenidoarsenates in different solvents, 20 we are interested in understanding how the solvent and coordination effects of hydrazine to influence crystal growth of chalcogenidoarsenates under solvothermal conditions. Now, we chose Mn/As/S as a model system to systematically explore the hydrazine-solvothermal syntheses under different conditions.…”