title: Facile synthesis of bis(dichalcogenophosphinate)s and a remarkable [Li8(OH)6]2+ polyhedron.
abstract: The synthesis and characterization of three lithium complexes of novel bis(dichalcogenophosphinate) ligands are reported: (PhP(S)(2)CH(2)CH(2)P(S)(2)Ph)Li(2)(THF)(4) (2), (PhP(Se)(2)CH(2)CH(2)P(Se)(2)Ph)Li(2)(THF)(4).(PhP(Se)(2)CH(2)CH(2)P(Se)(2)Ph)Li(2)(THF)(6) (3), and [PhP(Te)(2)CH(2)CH(2)P(Te)(2)Ph][Li(8)(OH)(6)(THF)(8)] (4). The synthetic route to these complexes proceeds via the insertion reaction of elemental chalcogens into the phosphorus-lithium bonds of 1,2-dilithio-1,2-di(phenylphosphine)ethylene (1). X-ray analysis of 2 revealed isobidentate coordination of the lithiums by the dithiophosphinate groups. In contrast, the diselenophosphinate groups in 3 coordinate the lithium centers in both isobidentate and monodentate modes, and the ditellurophosphinate groups in 4 form non-coordinate separate ion pairs. The countercation in 4 is shown to be a unique [Li(8)(OH)(6)](2+) rhombic dodecahedral polyhedron, putatively formed from the capping of a hexameric [Li(OH)](6) aggregate with lithium cations on its open faces.
authors.affiliation: Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, UK. r.davies@imperial.ac.uk
authors.forename: Robert P
authors.initials: RP
authors.lastname: Davies
authors.forename: M Giovanna
authors.initials: MG
authors.lastname: Martinelli
authors.forename: Laura
authors.initials: L
authors.lastname: Patel
authors.forename: Andrew J P
authors.initials: AJ
authors.lastname: White