Molecular Memory Switching Device Based on a Tetranuclear Organotin Sulfide Cage [(RSnIV)4(μ-S)6]·2CHCl3·4H2O (R = 2‑(Phenylazo)phenyl): Synthesis, Structure, DFT Studies, and Memristive Behavior

RSnCl3 (R = 2-phenylazophenyl) on reaction with Na2S·9H2O in a 1:1 mixture of acetone and methanol afforded a tetranuclear monoorganotin sulfide cage [(RSnIV)4(μ-S)6]·2CHCl3·4H2O (R = 2-phenylazophenyl) (1). Complex 1 crystallizes in the monoclinic space group P2/n. The molecular structure of 1 contains five-coordinate tin centers in distorted trigonal bipyramidal geometry. Complex 1 is monoorganotin sulfide derivative having a tetranuclear double-decker cage-like structure. In 1, four tin centers are bridged by a μ2-S unit affording a ubiquitous Sn–S–Sn motif among monoorganotin sulfide compounds. In addition, each tin also has intramolecular coordination to a nitrogen atom of a 2-phenylazophenyl substituent (N → Sn). The DFT calculation suggests that the complex 1 involves mainly ligand based transitions. The complex 1 based device was studied for its electrical behavior and was found to show stable, reproducible memristive behavior with an on–off ratio of 103, which suggests that the complex 1 is a promising material for memory device applications.