Organo-functionalised arsine and stibine organometallics; syntheses and structural characterisations of 1,3-[(PhCC)2Sb]2(CH2)3, As(CCPh)3, R2AsCH2AsR2 [R=Me3SiCC-, (Me3Si)2N- and 2-SPy] with π-stacking in the latter

A series of dinuclear organo-functionalised stibine and arsine ligands incorporating a range of hard, soft and π-donor moieties have been synthesised from the reactions of Cl2Sb(CH2)3SbCl2 and Cl2AsCH2AsCl2 with a range of organolithium reagents. The X-ray structures of 1,3-[(PhCC)2Sb]2(CH2)3 (1), As(CCPh)3 (2), R2AsCH2AsR2 [R=Me3SiCC, 3; (Me3Si)2N, 4; and 2-SPy 5] have been determined. Compound 5 associates into pseudo dimers as a result of intermolecular π–π stacking between the pyridyl groups on one end of two separate diarsine molecules. Whereas the bridging unit remains intact during the syntheses of 1 and 3–5, the formation of the mononuclear trisacetylide species 2, involves the unexplained cleavage of the bridging methylene unit.