Is the phosphorous atom a stereogenic center? Crystallographic findings in five new dithiophosphonate compounds supported with non covalent interaction index (NCI), theoretical approach and spectroscopic analysis

Abstract

The self-assembly of the dithiophosphonate tectons synthesized in this work generated novel supramolecular synthonsvia NH···S, NH···O, CH···S, CH···O, CH···π, and lp···π interactions. The reaction of the salts with chloro dithiastibocanes X(CH2CH2S)2SbCl (X = O, S) led to the formation of coordination compounds in which the crystal structures showed two new supramolecular synthons stabilized by CH···π and lp···π interactions. The theoretical study of the electronic density of the crystal and their synthons in the solid-state used the robust NCI index to confirm the nature of the interactions found. This study confirmed the connection between molecular and supramolecular chirality in the crystalline state. Three significant features unequivocally support the findings: the role of intramolecular interactions, the electronic density differences among diastereomers, and the nature of trans-annular bonds. The characterization of the salts: ammonium-menthoxy (4-methoxyphenyl) dithiophosphonate (1), triethylammonium-menthoxy (4-methoxyphenyl)-dithiophosphonate (2), triethylammonium-biphenyl-4‑methoxy (4-methoxyphenyl) dithiophosphonate (3), and the coordination compounds O(CH2CH2S)2Sb[S2P(biphenyl-4‑methoxy)(4-MeOC6H4)] (4) and S(CH2CH2S)2Sb[S2P(biphenyl-4‑methoxy)(4-MeOC6H4)] (5) was carried out by elemental analyses, IR, NMR (1H, 13C, 31P), and single-crystal X-ray diffraction analysis.