Hypervalent 5-Bi-12 derivatives containing dichalcogenoimidodiphosphinato ligands. Crystal structure and solution behaviour of [2(Me2NCH2)C6H4]BiCl[(XPR2)(YPR2)N](X, Y = O, S, Se; R, R= Me, Ph)

The reaction between [2-(Me2NCH2)C6H4]BiCl2 and M[(XPR2)(YPR2)N] in 1 1 molar ratio affords the new functionalised [2(Me2NCH2)C6H4]BiCl[(XPR2)(YPR2)N] derivatives [R = Me, R= Ph, X = O, Y = S (1); R = R= Ph, X = Y = S (2), Se (3)]. Variabletemperature NMR studies suggest a fluxional behaviour in solution. The investigation of the molecular structures of 1-3 by single-crystal X-ray diffraction revealed that the N atoms of the pendant CH2NMe2 arm are strongly coordinated to the Bi atom and the organophosphorus ligands act as a bidentate moiety through both chalcogens, thus resulting in a square pyramidal coordination geometry around the metal atoms. The analysis of the crystal packing of 2 and 3 reveals the presence of pairs of enantiomers (the metal center is chiral) associated through weak intermolecular Bi...Cl interactions. The crystal of 1 contains only the trans-O-Bi-Cl isomer as a 1 1 mixture of the two enantiomers, in a unique square pyramidal (C,N)BiCl(O,S) coordination geometry with five different atoms attached to the metal atom.