Synthesis, structures, DFT calculations, and Hirshfeld surface analysis of sulfonium derivatives of the closo-decaborate anion [B10X9-cyclo-S(CH2)4]– and [B10X9-cyclo-S(CH2CH2)2O]– (X = H, Cl, Br)

• Sulfur-containing derivatives of the closo-decaborate anion were synthesized. • Perhalogenated analogs of [2–B 10 Cl 9 –S(CH 2 ) 4 ] – and [2–B 10 Cl 9 -S(CH 2 CH 2 ) 2 O] – was obtained. • Quantum chemical calculations were performed for the obtained compounds. This work is devoted to the synthesis and modification of sulfur-containing derivatives of the closo -decaborate anion with cyclic substituents [2–B 10 H 9 –cyclo–S(CH 2 ) 4 ] – (1) and [2–B 10 H 9 -cyclo-S(CH 2 CH 2 ) 2 O] – (2) . Their perhalogenated analogs [2–B 10 Cl 9 –cyclo–S(CH 2 ) 4 ] – (3) , [2–B 10 Cl 9 -cyclo-S(CH 2 CH 2 ) 2 O] – (4) , [2–B 10 Br 9 –cyclo–S(CH 2 ) 4 ] – (5) , and [2–B 10 Br 9 -cyclo-S(CH 2 CH 2 ) 2 O] – (6) were synthesized. The obtained compounds were investigated by 11 B, 1 H, and 13 C NMR spectroscopy and single crystal X-ray diffraction. The analysis of Hirshfeld surfaces and quantum-chemical calculations by the DFT method made it possible to establish the contribution of various intermolecular contacts to the crystal packing of compounds 1–6 and to study the effect of substitution of hydrogen atoms in the boron cage on the strength of the B–S bond.