Antimony(III) dithiocarbamates: Structural studies and exploration of the rare Sb•••Sb interaction

Herein, we report synthesis and spectroscopic characterization of a new piperidine-based homoleptic antimony (III) dithiocarbamate complex Sb[S2CN(CH2)4CH(Bn)]3) (1) and solid state crystal structure of a piperazine- based complex Sb[S2CN(CH2)4N(Bn)]3 (2). This study identifies molecular and supramolecular features of the two compounds based on single crystal XRD data. Interestingly, complex 1 features an Sb center dot center dot center dot Sb (stibophilic) linkage, a rarely observed interaction in this class of compounds. To investigate the rarity of this stibophilic linkage CSD retrieved structures have been scrutinized and DFT studies conducted. XRD data unveiled that the linkage materializes in two possible ways: firstly, when monomers carrying pentagonal pyramidal coordination geometry adopt usual orientations (antiparallel alignment of the monomers attached through four-membered [Sb-S center dot center dot center dot]2 ring) and characteristically organized neighboring anchoring molecules influence them to sub-stantiate the linkage, and secondly when monomers align in unusual patterns (this is observed in both usual geometries, pentagonal pyramidal and trigonal antiprismatic). Interestingly, trigonal antiprismatic geometry with usual pattern of dimeric aggregation is deprived of the Sb center dot center dot center dot Sb linkage. Furthermore, DFT data are well consistent with the findings, and convincingly explains the rarity of the linkage.

Automated summary

In this study, a new piperidine-based homoleptic antimony (III) dithiocarbamate complex and a piperazine-based complex were synthesized and spectroscopically characterized. The molecular and supramolecular features of these compounds were identified using single crystal XRD data. Interestingly, a rarely observed Sb center dot center dot center dot Sb linkage was observed in one of the complexes. This rarity was investigated through CSD retrieval and DFT studies, and the findings were consistent with the experimental results.