Inorg. Chem. 2000, 39, 2801-2806
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Gold Complexes with Potentially Tri- and Tetradentate Phosphinothiolate Ligands Kirstin Ortner,†,‡ Louise Hilditch,§ Yifan Zheng,§ Jonathan R. Dilworth,§ and Ulrich Abram*,| Institute of Inorganic Chemistry, University of Tu¨bingen, Auf der Morgenstelle 18, D-72076 Tu¨bingen, Germany, Inorganic Chemistry Laboratories, University of Oxford, South Parks Road, Oxford, OX1 3QR, U.K., and Institute of Chemistry/Inorganic and Analytical Chemistry, Freie Universita¨t Berlin, Fabeckstrasse 34-36, D-14195 Berlin, Germany ReceiVed January 5, 2000 Reactions of [Au(PPh3)Cl], (Bu4N)[AuCl4] and the organometallic gold complex [Au(damp-C1,N)Cl2] (damp- ) 2-(N,N-dimethylaminomethyl)phenyl) with the potentially tri- and tetradentate proligands PhP(C6H3-SH-2R-3)2 (H2L1a, R ) SiMe3; H2L1b, R ) H) and P(C6H4-SH-2)3 (H3L2) result in the formation of mono- or dinuclear gold complexes depending on the precursor used. Monomeric complexes of the type [AuL1Cl] are formed upon the reaction with [Au(damp-C1,N)Cl2], but small amounts of dinuclear [AuL1]2 complexes with gold in two different oxidation states, +1 and +3, have been isolated as side-products. The dinuclear compounds are obtained in better yields from [AuCl4]-. A dinuclear complex having two Au(III) centers can be isolated from the reaction of [Au(PPh3)Cl] with H3L2, whereas from the reaction with H2L1b the mononuclear [Au(Ph3P)HL1b] is obtained, which contains a three-coordinate gold atom. Comparatively short gold-gold distances have been found in the dinuclear complexes (2.978(2) and 3.434(1) Å). They are indicative of weak gold-gold interactions, which is unusual for gold(III).
Introduction The coordination chemistry of potentially tri- and tetradentate proligands of the types PhP(C6H3-SH-2-R-3)2 (H2L1a, R ) SiMe3; H2L1b, H) and P(C6H4-SH-2)3 (H3L2) has been
investigated to a relatively limited extent. Mononuclear complexes have been described for the group V to group VIII transition metals1-8 as well as for samarium,9 tin,9 and nickel.4 * To whom correspondence should be addressed, E-mail: abram@ chemie.fu-berlin.de. † University of Tu ¨ bingen. ‡ Present address: University of Zu ¨ rich, Institute of Inorganic Chemistry, Winterthurerstrasse 190, CH-8057 Zu¨rich, Switzerland. § University of Oxford. | Freie Universita ¨ t Berlin. (1) Block, E.; Gernon, M.; Kang; H.; Ofori-Okai, G.; Zubieta, J. Inorg. Chem. 1991, 30, 1736. (2) Dilworth, J. R.; Hutson, A. J.; Lewis, J. S.; Miller, J. R.; Zheng, Y.; Chen, Q.; Zubieta, J. J. Chem. Soc., Dalton Trans. 1996, 1093. (3) Hsu, H.; Koch, S. A.; Popescu, C. V.; Munck, E. J. Am. Chem. Soc. 1997, 119, 8371. (4) Dao, H. N.; Hsu, H.; Miller, M.; Koch, S. A. J. Am. Chem. Soc. 1996, 118, 8963. (5) Dilworth, J. R.; Griffith, D. V.; Parrot, S. J.; Zheng, Y. J. Chem. Soc., Dalton Trans. 1997, 2931. (6) Perez-Lourido, P.; Romero, J.; Garcia-Vazquez, J.; Sousa, A.; Maresca, K. P.; Rose, D. J.; Zubieta, J. Inorg. Chem. 1998, 37, 3331. (7) De Vries, N.; Davison, A.; Jones, A. G. Inorg. Chim. Acta 1989, 165, 9.
For the last metal, however, bridging coordination of metal centers with the ligand H2L1 or H3L2 has also been observed. These complexes show unusual coordination polyhedra and redox behavior.2,10 Thus, [Ni2{PhP(C6H4-S)3}2]2+ can be oxidized to yield the mixed-valence [Ni(II)/Ni(III)] complex [Ni2{PhP(C6H4-S-2)3}2]+. The oxidation is associated with considerable changes in the molecular structure and a shortening of the metal-metal distances, which is indicative of Ni-Ni interactions in the mixed-valence species.10 The unusual abilities of phosphinothiolate ligands to stabilize complexes with metals in high formal oxidation states prompted us to investigate their chemistry with gold. The synthesis and structure of a mononuclear gold(III) cation with the bidentate {Ph2P(C6H4-S-2)}- ligand has been reported previously, showing that reduction to gold(I) or elemental gold is not predominant when starting from gold(III) precursors, whereas polymeric products are generally formed when gold(I) precursors are used.11 Here, we describe reactions of H2L1 and H3L2 with (Bu4N)[AuCl4], [Au(Ph3P)Cl], and the organometallic gold(III) complex [Au(damp-C1,N)Cl2] (1) (damp- ) 2-(N,N-dimethylaminomethyl)phenyl). The [Au(damp)] moiety has been shown to stabilize gold(III) with a wide range of coligands including thiolates and phosphines.12-14 (8) De Vries, N.; Cook, J.; Jones, A. G.; Davison, A. Inorg. Chem. 1991, 30, 2662. (9) Froelich, N.; Hitchcock, P. B.; Hu, J.; Lappert, M. F.; Dilworth, J. R. J. Chem. Soc., Dalton Trans. 1996, 1941. (10) Franolic, J. D.; Yu, W.; Millar, M. J. Am. Chem. Soc. 1992, 114, 6587. (11) Dilworth, J. R.; Hutson, A. J.; Zubieta, J.; Chen, Q. Transition Met. Chem. 1994, 19, 61. (12) Vicente, J.; Chicote, M. T.; Bermudez, M. D.; Jones, P. G.; Fittschen, C.; Sheldrick, G. M. J. Chem. Soc., Dalton Trans. 1986, 2361. (13) Parish, R. V.; Howe, B. P.; Wright, J. P.; Mack, J.; Pritchard, R. G.; Buckley, R. G.; Elsome, A. M.; Fricker, S. P. Inorg. Chem. 1996, 35, 1666.
10.1021/ic000015y CCC: $19.00 © 2000 American Chemical Society Published on Web 05/27/2000
2802 Inorganic Chemistry, Vol. 39, No. 13, 2000
Experimental Section Au(damp-C1,N)Cl2]14 and [Au(Ph3P)Cl]15 were prepared using literature procedures. (Bu4N)[AuCl4] was obtained by addition of an excess of (Bu4N)Cl to an aqueous solution of HAuCl4 and subsequent recrystallization from CH2Cl2. PhP(C6H3-SH-2-R-3)2 (R ) H, SiMe3) (H2L1) and P(C6H4-SH-2)3 (H3L2) were synthesized according to ref 16. IR spectra were recorded on a Perkin-Elmer Spectrum 1000 and FAB mass spectra obtained using a TSQ 70 (FINNIGAN MAT) instrument with nitrobenzyl alcohol as the matrix (8 keV, xenon). Fastatom bombardment (FAB) mass spectra with m/z > 1000 and field desorption (FD) spectra were recorded on a TSQ (FINNIGAN MAT 711A). Electrospray (ES) mass spectra were obtained using an API III TAGA 6000E triple-quadrupole mass spectrometer (Sciex, Canada). Preparation of Compounds. [Au{PhP(C6H3-S-2-SiMe3-3)2}Cl] (2) and [Au2{PhP(C6H3-S-2-SiMe3-3)2}2] (3). [Au(damp-C1,N)Cl2] (200 mg, 0.5 mmol) was dissolved in acetone (3 mL), and PhP(C6H3SH-2-SiMe3-3)2 (H2L1a) (235 mg, 0.5 mmol) dissolved in CH2Cl2 (2 mL) was added. The clear, orange-red solution was stirred for 30 min and reduced in volume. A small amount of red blocks crystallized from this solution within 1 h. They were removed by filtration, dried in a vacuum, and analyzed to be 3. Further concentration of the mother liquor gave red columns of 2. Yield of 2: 266 mg (76%). Found: C, 41.3; H, 4.1; Cl, 4.9. Anal. Calcd for C24H29AuPS2Si2Cl: C, 41.4; H, 4.1; Cl, 5.1. IR (νmax/cm-1): 1560, 1540 s (CdC), 1438 s (P-phenyl), 855, 838 s (SiMe3), 308 (AuCl). FAB+ MS (m/z, %, assignment): 485 (30, [Au(PhPC6H3SSiMe3)]+), 453 (100, [Au(PhPC6H3SiMe3)]+), 307 (38, [PhPC6H3SiMe3)]+). FD-MS in CH2Cl2 (m/z, assignment): 700 (M+). Yield of 3:
