X-ray structures of the tris(2,4-xylyl)phosphane and its trisulfonated derivative: Molecular architecture of a water-soluble sulfonated phosphane with propeller chirality

The structure of tris(2,4-xylyl)phosphane (1) is reported and supramolecular assembly of gua⁺ salt of tris(2,4-dimethyl-5-sulfonatophenyl)phosphane co-crystal with guanidine chloride (2) is analyzed in detail. Weaving hydrogen bond ribbons with polar and apolar stabilizing pillars as well as stacking interaction of phenyl rings resulting sixfold phenyl embraces interpenetrating with the polar networks were found. Both compounds are racemate, show propeller chirality and 2 crystallizes in non-centrosymmetric space group (C3 symmetry) with the ortho-methyl groups outside of the molecular cone. According to the DFT calculations on the anion of 2, the high barrier of concerted ring rotation opens the possibility of resolving the enantiomers through hydrogen bonds to chiral donors.