Coordination chemistry of diselenophosphinate complexes: the x-ray

Inorg. Chem. 2004, 43, 4802−4804

Coordination Chemistry of Diselenophosphinate Complexes: The X-ray Single-Crystal Structures of [K(Se2PPh2)(THF)2]2 and [In(Se2PPh2)3]‚L (L ) THF, PhMe)
Robert P. Davies,* Claire V. Francis, Andrew P. S. Jurd, M. Giovanna Martinelli, Andrew J. P. White, and David J. Williams Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ,U.K.
Received April 2, 2004

Reaction of potassium diphenylphosphide with elemental selenium is shown to give [K(Se2PPh2)(THF)2]2 1, which further reacts with InCl3 to yield [In(Se2PPh2)3] 2. Crystallization of 2 from either THF or PhMe gave 2‚THF or 2‚PhMe, respectively, both of which form loosely linked dimers in the solid state via Se‚‚‚Se intermolecular van der Waals interactions.Decomposition of 2 has been studied by TGA.

The chemistry of metal selenolates is of topical interest, due in part to their potential use as single-source precursors to binary and ternary metal chalcogenides.1 Within this area, we have recently been interested in the synthesis and coordination chemistry of chalcogeno-phosphorus ligand systems, and have published of late on the synthesis of lithiumselenophosphinite, diselenophosphinate, and triselenophosphonate complexes.2 These seleno-phosphorus ligands were shown to be more stable, easier to handle, and far less pungent than alkyl and aryl selenolates.2,3 This has now led us to look at the synthesis and characterization of other main group metal complexes of these ligands. The indium(III) complexes of seleno-phosphorus ligands are of particularinterest to us due to their potential application as single-source precursors to indium selenide thin films and quantum dots. Precedent to these applications lies in the reported use of dithiophosphinate and phosphinochalcogenoic amidate complexes such as [Cd(S2PR2)2] (R ) CH3,4 C2H55) and [M{tBu2P(Se)NR}2] (M ) Zn, Cd, Cr,
* To whom correspondence should be addressed. E-mail: r.davies@imperial.ac.uk. (1) (a) Singh, H. B.; Sudha, N. Polyhedron 1996, 15, 745-763. (b) Arnold, J. In Progress in Inorganic Chemistry; Karlin, K. D., Ed.; Wiley: New York, 1995; Vol. 43, pp 353-418. (c) Gleizes, A. N. Chem. Vap. Deposition 2000, 6, 155-173. (d) Bochmann, M. Chem. Vap. Deposition 1996, 2, 85-96. (e) Lazell, M.; O’Brien, P.; Otway, D. J.; Park, J.-H. J. Chem. Soc., Dalton Trans. 2000, 4479-4486.(2) Davies, R. P.; Martinelli, M. G. Inorg. Chem. 2002, 41, 348-352. (3) Clegg, W.; Davies, R. P.; Snaith, R.; Wheatley, A. E. H. Eur. J. Inorg. Chem. 2001, 1411-1413. (4) Takahashi, Y.; Yuki, R.; Sugiura, M.; Motojima, S.; Sugiyama, K. J. Cryst. Growth 1980, 50, 491-497. (5) Evans, M. A. H.; Williams, J. O. Thin Solid Films 1982, 87, L1-L2.

Mn, Fe, Co; R ) iPr, c-C6H11)6 for the growth ofsemiconducting metal chalcogenide thin films using chemical vapor deposition (CVD) processes, and in the recently reported effectiveness of imino-bis(diisopropylphosphine selenide) complexes, e.g., Cd[N(SePiPr2)2]2, as reagents for the one-step synthesis of metal selenide quantum dots.7 In addition, although dithiophosphinate complexes of main group metals are well-known,8 there are very fewstructurally characterized main group metal complexes of the homologous diselenophosphinates or diselenophosphates, the only examples being the alkali metal complexes [Ph2PSe2Li‚THF‚ TMEDA]2 [TMEDA ) {(CH3)2NCH2}2], [Na2(Se2PPh2)2‚ THF‚5H2O],9 and [K2(PhPSe2)2CH2]10 Potassium diselenophosphinate [K(Se2PPh2)(THF)2]2 1 was obtained in 79% yield from the reaction of potassium diphenylphosphide with 2 equiv ofgray selenium powder in THF/toluene (Scheme 1). Scheme 1 8 8 Ph2PK 9 [K(Se2PPh2)(THF)2]2 9 In(Se2PPh2)3 -KCl THF X-ray diffraction studies11 show 1 to crystallize as discrete centrosymmetric dimers with a central K2P2Se4 cage bounded by phenyl and THF units (Figure 1). The P-Se bond lengths of 2.132(2) Å [Se(1)] and 2.150(2) Å [Se(2)] are intermediate between those expected for P-Se single (2.26...