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Organometallics 2009, 28, 4606–4609 DOI: 10.1021/om9002544
Trapping of a 12-Valence-Electron Osmium Intermediate Marıa L. Buil, Miguel A. Esteruelas,* Karin Garces, Jorge Garcıa-Raboso, and Montserrat Olivan Departamento de Quımica Inorg anica, Instituto de Ciencia de Materiales de Arag on, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain Received April 6, 2009
Osmium is reducing and prefers coordination saturation and redox isomers with more metal-carbon bonds.1 As a consequence of this, there are a number of saturated complexes with the metal center in a high oxidation state that are synthons of highly unsaturated species, having 14 and 12 valence electrons, with the metal center in a low oxidation state. They are dihydrogen and polyhydride derivatives containing carbon donor groups. Under the reaction conditions, the organic ligands undergo reduction in the coordination sphere of the metal center and are subsequently released to afford the unsaturated species.2 The hydride-dihydrogen complex [OsH(η2-H2){κ3N,C, C-CH2dCH-o-C5H4N}(PiPr3)2]BF4 (1) seems to be an example of these types of compounds. It reacts with benzophenone3 and R,β-unsaturated ketones4 to give
ligand (Scheme 1). The formation of these compounds can be easily rationalized if one assumes that the concerted addition of the dihydrogen ligand to the olefinic substituent of the coordinated 2-vinylpyridine group5 and the subsequent release of the resulting 2-ethylpyridine molecule lead to the 12-valence-electron monohydride cation “[OsH(PiPr3)2]+”. This highly unsaturated species should give the formed complexes by means of the C-H activation of the ketones and the NH tautomerization of 2ethylpyridine.6 We have now observed that in toluene, benzene, and fluorobenzene under reflux, complex 1 loses 2-ethylpyridine7 to afford “[OsH(PiPr3)2]+”. Under these conditions, the monohydride is trapped by the solvents to form the arene derivatives [OsH(η6-C6H5R)(PiPr3)2]BF4 (R = CH3 (2), H (3), F (4)), which are isolated as white solids in 60-70% yield. The 12-valence-electron monohydride cation is also generated by protonation of the hexahydride OsH6(PiPr3)2 (5). Thus, the treatment of toluene-acetone (5:1) and benzeneacetone (5:1) solutions of 5 with 1.5 equiv of HBF4 3 OEt2 for 20 h under reflux leads to 2 and 3, which are isolated in 67% and 76% yields, respectively (Scheme 2). In this case the monohydride cation is generated as a result of the initial protonation of 5 and the subsequent release of three hydrogen molecules from the resulting intermediate [OsH3(η2-H2)2(PiPr3)2]+. In agreement with this, Caulton
Scheme 1
Summary: The hydride-dihydrogen complex [OsH(η2-H2) {κ3N,C,C-CH2dCH-o-C5H4N}(PiPr3)2]BF4 (1) is a “functional equivalent” of the 12-valence-electron monohydride cation “[OsH(PiPr3)2]+”, which is trapped by aromatic solvents, such as toluene, benzene, and fluorobenzene to form the arene derivatives [OsH(η6-C6H5R)(PiPr3)2]BF4 (R = CH3 (2), H (3), F (4)). This “functional equivalent” can be also generated by protonation of the hexahydride OsH6(PiPr3)2 (5) with 1 equiv of HBF4 and subsequent release of three hydrogen molecules. The monohydride is also trapped by 5. The protonation of the latter with 0.5 equiv of HBF4 yields the heptahydride dimer [{OsH2(PiPr3)2}2(μ-H)3]BF4 (6), which does not undergo exchange of bridging and terminal hydrides.
[Os{C6H4C( O)Ph}(η2-H2){κC-[HNC5H3Et]}(PiPr3)2]BF4 and [Os{C(Ph)CHC( O)R}(η2-H2){κC-[HNC5H3Et]}(PiPr3)2]BF4 (R = Ph, CH3), respectively, containing a metalated ketone and a NH-tautomerized 2-ethylpyridine *To whom correspondence should be addressed. E-mail: maester@ unizar.es. (1) (a) Caulton, K. G. J. Organomet. Chem. 2001, 617-618, 56. (b) Esteruelas, M. A.; L opez, A. M. Organometallics 2005, 24, 3584. (c) Esteruelas, M. A.; L opez, A. M.; Olivan, M. Coord. Chem. Rev. 2007, 251, 795. (2) (a) Barrio, P.; Esteruelas, M. A.; O~ nate, E. Organometallics 2002, 21, 2491. (b) Barrio, P.; Esteruelas, M. A.; O~ nate, E. Organometallics 2003, 22, 2472. (c) Esteruelas, M. A.; Lled os, A.; Olivan, M.; O~ nate, E.; Tajada, M. A.; Ujaque, G. Organometallics 2003, 22, 3753. (d) Eguillor, B.; Esteruelas, M. A.; Olivan, M.; O~ nate, E. Organometallics 2005, 24, 1428. (e) Bola~ no, T.; Castarlenas, R.; Esteruelas, M. A.; Modrego, J.; O~ nate, E. J. Am. Chem. Soc. 2005, 127, 11184. (3) Buil, M. L.; Esteruelas, M. A.; Garces, K.; Olivan, M.; O~ nate, E. J. Am. Chem. Soc. 2007, 129, 10998. (4) Buil, M. L.; Esteruelas, M. A.; Garces, K.; Olivan, M.; O~ nate, E. Organometallics 2008, 27, 4680. pubs.acs.org/Organometallics
Published on Web 05/22/2009
(5) (a) Liu, S. H.; Huang, X.; Ng, W. S.; Wen, T. B.; Lo, M. F.; Zhou, Z. Y.; Williams, I. D.; Lin, Z.; Jia, G. Organometallics 2003, 22, 904. (b) Jia, G.; Lin, Z.; Lau, C. P. Eur. J. Inorg. Chem. 2003, 2551. (c) Barrio, P.; Esteruelas, M. A.; O~ nate, E. Organometallics 2004, 23, 3627. (6) Esteruelas, M. A.; Fernandez-Alvarez, F. J.; O~ nate, E. Organo metallics 2008, 27, 6236. (b) Esteruelas, M. A.; Fernandez-Alvarez, F. J.; Olivan, M.; O~ nate, E. Organometallics 2009, 28, 2276. (7) Its release from 1 was confirmed by GC-MS. r 2009 American Chemical Society
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Scheme 2
Figure 1. Molecular diagram of the cation of 2. Selected bond lengths (A˚) and angles (deg): Os-P(1) = 2.3723(10), Os-P(2) = 2.3649(10), Os-H = 1.584(10), Os-M = 1.777 (4) (M = center of the arene ring); P(1)-Os-P(2) = 103.51(3), P(1)-Os-H(01) = 78.6(16), P(2)-Os-H(01) = 78.1(16).
and co-workers8 have reported that, at room temperature, the addition of HBF4 3 OEt2 to dichloromethane solutions of 5 yields [OsH3(η2-H2)2(PiPr3)2]+, which in acetonitrile loses molecular hydrogen to give [OsH(CH3CN)3(PiPr3)2]+ via the trihydride [OsH3(CH3CN)2(PiPr3)2]+. As expected, the cation [OsH-(CH3CN)3(PiPr3)2]+ is also formed when an acetonitrile solution of 1 is stirred for 2 h at room temperature. Figure 1 shows a view of the structure of the cation of 2. The geometry around the osmium center is close to octahedral, with the arene ligand occupying three sites of a face. The mutually cis-disposed phosphine groups experience a large steric hindrance as a consequence of their cone angle (160°).9 Thus, the P(1)-Os-P(2) angle of 103.51(3)° strongly deviates from the ideal value of 90°. This angle is similar to other P-M-P angles previously found in complexes with two triisopropylphosphine ligands mutually cis-disposed.10 In the 1H NMR spectra of these compounds in dichloromethane-d2, the most noticeable resonances are those corresponding to the hydride ligands, which appear between -11.9 and -12.6 ppm. For 2 and 3 they are observed as triplets with H-P coupling constants of 37.4 and 38.6 Hz, respectively, while for 4 it is observed as a double triplet with coupling constants of 37.5 (H-P) and 8.8 (H-F) Hz. The 31P{1H} NMR spectra contain singlets at about 14 ppm. Hexahydride 5 is also able to trap the monohydride cation. Its ability to do so is even higher than that of the aromatic solvents. Thus, the treatment of toluene and benzene solutions of 5 with 0.5 equiv of HBF4 3 OEt2 for 1.5 h under reflux gives the heptahydride dimer [{OsH2(PiPr3)2}2(μ-H)3]BF4 (8) Smith, K.-T.; Tilset, M.; Kuhlman, R.; Caulton, K. G. J. Am. Chem. Soc. 1995, 117, 9473. (9) Tolman, C. A. Chem. Rev. 1977, 77, 313. :: :: (10) (a) Werner, H.; Schafer, M.; Nurnberg, O.; Wolf, J. Chem. Ber. 1994, 127, 27. (b) Esteruelas, M. A.; Lahoz, F. J.; O~ nate, E.; Oro, L. A.; Rodrıguez, L.; Steinert, P.; Werner, H. Organometallics 1996, 15, 3436. (c) Chen, W.; Esteruelas, M. A.; Herrero, J.; Lahoz, F. J.; Martın, M.; O~ nate, E.; Oro, L. A. Organometallics 1997, 16, 6010. (d) Buil, M. L.; Esteruelas, M. A.; Garcıa-Yebra, C.; Gutierrez-Puebla, E.; Olivan, M. Organometallics 2000, 19, 2184. (e) Esteruelas, M. A.; L opez, A. M.; O~ nate, E.; Royo, E. Inorg. Chem. 2005, 44, 4094. (f) Esteruelas, M. A.; L opez, A. M.; O~ nate, E.; Royo, E. Organometallics 2005, 24, 5780.
(6), which is isolated as an orange solid in 81% yield (eq 1). The formation of 6 involves, in addition to the stabilization of unsaturated monohydride, hydride transfer from the Os (VI) metal center to the Os(II) metal center.
Figure 2 shows a view of the structure of the cation of 6, which is similar to that of the trichloride-bridged [{OsH2(PiPr3)2}2(μ-Cl)3]+.11 The heptahydride cation consists of two OsH2(PiPr3)2 moieties linked by three bridging hydrides. The two P-Os-P planes intersect at a 67.40(7)° angle. A crystallographic C2 axis passes through H(04) and the midpoint between Os and Os(A). The OsH2(PiPr3)2 substructures with P-Os-P and H-Os-H angles of 114.01(4) and 125(2)°, respectively, agree well with that of OsH2Cl2(PiPr3)2.12 The separation between the osmium atoms of 2.5490(6) A˚ is typical for osmium dimers bridged by three hydride ligands.13 Its short value is consistent with three Os-H-Os 3c-2e bonds.14 The 1H NMR spectrum of 6 indicates that, in contrast to the case for the rhenium derivative [{ReH2(PMePh2)2}2(μ-H)3]-,15 this complex does not undergo exchange of bridging and terminal hydrides. The bridging hydrides display at -9.78 ppm a quintuplet with a H-P coupling constant of 8.1 Hz, whereas the resonance corresponding to the terminal hydrides is observed at -13.80 ppm as a (11) Kuhlman, R.; Streib, W. E.; Caulton, K. G. Inorg. Chem. 1995, 34, 1788. (12) Aracama, M.; Esteruelas, M. A.; Lahoz, F. J.; Lopez, J. A.; Meyer, U.; Oro, L. A.; Werner, H. Inorg. Chem. 1991, 30, 288. (13) (a) Cabeza, J. A.; Mann, B. E.; Maitlis, P. M.; Brevard, C. J. Chem. Soc., Dalton Trans. 1988, 629. (b) Schulz, M.; Stahl, S.; Werner, H. J. Organomet. Chem. 1990, 394, 469. (c) Bruno, J. W.; Huffman, J. C.; Green, M. A.; Zubkowski, J. D.; Hatfield, W. E.; Caulton, K. G. :: Organometallics 1990, 9, 2556. (d) Therrien, B.; Vieille-Petit, L.; Suss:: Fink, G. J. Mol. Struct. 2005, 738, 161. (e) Suss-Fink, G.; Therrien, B. Organometallics 2007, 26, 766. (14) (a) Esteruelas, M. A.; Garcıa, M. P.; Lahoz, F. J.; Martın, M.; Modrego, J.; O~ nate, E.; Oro, L. A. Inorg. Chem. 1994, 33, 3473. (b) Buil, M. L.; Esteruelas, M. A.; Modrego, J.; O~ nate, E. New. J. Chem. 1999, 23, 403. (c) Esteruelas, M. A.; Garcıa-Yebra, C.; Olivan, M.; O~ nate, E. Inorg. Chem. 2006, 45, 10162. (15) Hinman, J. G.; Abdur-Rashid, K.; Lough, A. J.; Morris, R. H. Inorg. Chem. 2001, 40, 2480.
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Figure 2. Molecular diagram of the cation of 6. Selected bond lengths (A˚) and angles (deg): Os-P(1) = 2.3231(12), Os-P(2) = 2.3154(12), Os-OsA = 2.5490(6); P(1)-Os-P(2) = 114.01(4), H(01)-Os-H(02) = 125(2).
triplet with a H-P coupling constant of 29.7 Hz. The 31P {1H} NMR spectrum contains a singlet at 53.3 ppm. In conclusion, in aromatic solvents, both the release of 2-ethylpyridine from the hydride-dihydrogen complex [OsH(η2 -H2){κ3 N,C,C-CH2dCH-o-C5H4 N}(P i Pr3) 2]BF4 and the protonation of the hexahydride compound OsH6(PiPr3)2 with 1 equiv of HBF4 give rise to the 12-valenceelectron monohydride cation “[OsH(PiPr3)2]+”, which is trapped by the solvents to form the arene derivatives [OsH(η6-arene)(PiPr3)2]BF4. The complex OsH6(PiPr3)2 is also able to trap the monohydride cation. In the absence of acid, its protonation yields the heptahydride dimer [{OsH2(PiPr3)2}2(μ-H)3]BF4. The reducing character of osmium and its preference for coordination saturation have been often noted to justify the relative lack of development of osmium chemistry in comparison with that of ruthenium. The results shown here prove, however, that these features can become an advantage. As a consequence of them, we can handle compounds which are synthetic equivalents of highly unsaturated species, with fascinating reactivity.3,4 Therefore, the osmium chemistry is not less useful than that of ruthenium but is even more versatile.
Experimental Section All reactions were carried out with rigorous exclusion of air using Schlenk-tube techniques. Solvents were dried by standard procedures and distilled under argon prior to use. The starting materials [OsH(η2-H2){κ3N,C,C-CH2dCH-o-C5H4N}(PiPr3)2]BF45c (1) and OsH6(PiPr3)212 (5) were prepared by published methods. Chemical shifts (expressed in parts per million) are referenced to residual solvent peaks (1H, 13C{1H}), external H3PO4 (31P{1H}), or CFCl3 (19F). Coupling constants, J and N, are given in hertz. Preparation of [OsH(η6-C6H5CH3)(PiPr3)2]BF4 (2). Method a. A Schlenk flask equipped with a Teflon closure was charged with 1 (300 mg, 0.43 mmol), and toluene (10 mL) was added. The mixture was heated for 2.5 h at 110 °C. After the mixture was cooled in an ice bath, a white solid was formed. The solvent was removed, and the solid was washed with diethyl ether and dried in vacuo. Yield: 200 mg (68%). Method b. A solution of 5 (100 mg, 0.193 mmol) in tolueneacetone (10:2) was treated with 1.5 equiv of HBF4 3 OEt2
Buil et al. (39 μL, 0.290 mmol). The resulting solution was heated at 110 °C for 20 h. During this time the solution changed from colorless to yellow and a white solid appeared. The white solid was washed with diethyl ether and dried in vacuo. Yield: 86.4 mg (67%). Anal. Calcd for C25H51BF4OsP2: C, 43.48; H, 7.44. Found: C, 43.70; H, 6.98. IR (Nujol, cm-1): ν(OsH) 2133 (m); ν(Ph) 1519 (m); ν(BF4) 1033 (vs). MS (MALDI-TOF): m/z 605.4 (4), [M]; 443.3 (100), [MH] - [PiPr3] - [H]. 1H NMR (400.1 MHz, CD2Cl2, 293 K): δ 6.30 (t, JH-H = 5.6, 1H, p-C6H5CH3), 5.72 (dd, JH-H = JH-H0 = 5.6, 2H, m-C6H5CH3), 5.11 (d, JH-H = 5.6, 2H, o-C6H5CH3), 2.71 (s, 3H, CH3), 2.17 (m, 6H, PCHCH3), 1.27 (dvt, N = 15.6, JH-H = 8.4, 18H, PCHCH3), 1.26 (dvt, N = 13.6, JH-H = 7.8, 18H, PCHCH3), -12.37 (t, JH-P = 37.4, 1H, OsH). 31P{1H} NMR (162.0 MHz, CD2Cl2, 293 K): δ 13.9 (s). 13C{1H}-APT NMR plus HMBC and HSQC (75.5 MHz, CD2Cl2, 293 K): δ 99.6 (t, JC-P = 2.8, CCH3), 87.6 (s, m-C6H5CH3), 80.7 (s, p-C6H5CH3), 78.0 (s, o-C6H5CH3), 30.2 (vt, N = 27.9, PCHCH3), 21.4 (s, CCH3), 20.8 and 20.5 (both s, PCHCH3). Preparation of [OsH(η6-C6H6)(PiPr3)2]BF4 (3). Method a. In a Schlenk tube were added 1 (240 mg, 0.34 mmol) and 10 mL of benzene. The resulting mixture was heated under reflux for 2.5 h. After the mixture was cooled to room temperature, a white precipitate was formed. The solid was decanted, and the solvent was removed. The precipitate was washed with diethyl ether and dried in vacuo. Yield: 162 mg (70%). Method b. A solution of 5 (100 mg, 0.193 mmol) in benzeneacetone (10:2) was treated with 1.5 equiv of HBF4 3 OEt2 (39 μL, 0.290 mmol). The resulting solution was heated at 80 °C for 20 h. During this time the solution changed from colorless to yellow. The solution was concentrated to dryness in vacuo. The yellow residue was treated with diethyl ether to give a white solid that was washed with diethyl ether and dried in vacuo. Yield: 86 mg (76%). Anal. Calcd for C24H49BF4OsP2: C, 42.60; H, 7.30. Found: C, 42.60; H, 7.38. IR (Nujol, cm-1): ν(OsH) 2114 (w); ν(BF4) 1055 (vs). MS (MALDI-TOF): m/z 591.3 (35), [M]; 429.2 (100), [MH] - [PiPr3] - [H]. 1H NMR (400.1 MHz, CD2Cl2, 293 K): δ 5.70 (s, 6H, Ph), 2.16 (m, 6H, PCHCH3), 1.26 (dvt, N = 16.0, JH-H = 6.8, 18H, PCHCH3), 1.24 (dvt, N = 14.8, JH-H = 6.8, 18H, PCHCH3), -12.50 (t, JH-P = 38.6, 1H, OsH). 31 P{1H} NMR (121.5 MHz, CD2Cl2, 293 K): δ 13.1 (s). 13C1 { H}-APT NMR (75.5 MHz, CD2Cl2, 293 K): δ 82.5 (s, Ph), 30.2 (vt, N = 27.6, PCHCH3), 20.8 and 20.6 (both s, PCHCH3). Preparation of [OsH(η6-C6H5F)(PiPr3)2]BF4 (4). A light brown solution of 1 (310 mg, 0.44 mmol) in 12 mL of fluorobenzene was heated under reflux for 3 h. The resulting solution was filtered through Celite, and the solvent was removed in vacuo. The addition of diethyl ether to the resulting residue led to a light brown solid, which was washed with further portions of diethyl ether and dried in vacuo. Yield: 186 mg (61%). Anal. Calcd for C24H48BF5OsP2: C, 41.50; H, 6.97. Found: C, 41.08; H, 7.11. IR (Nujol, cm-1): ν(OsH) 2126 (m); ν(Ph) 1602 (m), 1570 (m); ν(BF4) 1053 (vs). MS (MALDI-TOF): m/z 609.4 (4), [M]; 447.3 (100), [MH] - [PiPr3] - [H]. 1H NMR (300.1 MHz, CD2Cl2, 293 K): δ 6.00 (m, 1H, p-C6H5F), 5.78 (m, 2H, m-C6H5F), 5.6 (m, 2H, o-C6H5F), 2.19 (m, 6H, PCHCH3), 1.28 (dvt, N = 13.7, JH-H = 7.3, 18H, PCHCH3), 1.25 (dvt, N = 13.7, JH-H = 7.3, 18H, PCHCH3), -11.94 (dt, JH-P = 37.5, JH-F = 8.8, 1H, OsH). 31P{1H} NMR (121.5 MHz, CD2Cl2, 293 K): δ 14.3 (s). 19F{1H} NMR (282.4 MHz, CD2Cl2, 293 K): δ -136.7 (C6H5F), -152.5 (br, BF4). 13C{1H}-APT NMR plus HMBC and HSQC (75.5 MHz, CD2Cl2, 293 K): δ 135.3 (dt, JC-F = 276.9, JC-P = 3.2, C-F), 84.8 (d, JC-F = 5.9, m-C6H5F), 79.7 (s, p-C6H5F), 68.9 (dt, JC-F = 21.4, JC-P = 2.6, o-C6H5F), 30.2 (vt, N = 25.0, PCHCH3), 29.8 (vt, N = 24.7, PCHCH3), 20.8 and 20.5 (both s, PCHCH3). Reaction of OsH6(PiPr3)2 (5) with 0.5 Equiv of HBF4 3 OEt2 in Toluene: Preparation of [{OsH2(PiPr3)2}2(μ-H3)]BF4 (6). A colorless solution of 5 (100 mg, 0.19 mmol) in 15 mL of toluene was treated with 0.5 equiv of HBF4 3 OEt2 (13.2 μL, 0.095 mmol) and
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heated under reflux for 1.5 h. After this time it was cooled to room temperature. During the course of reaction an orange solid was formed. The solid was separated by decantation, washed with diethyl ether (3 5 mL), and dried in vacuo. Yield: 88.3 mg (81%). Anal. Calcd for C36H91BF4Os2P4: C, 38.77; H, 8.22. Found: C, 38.30; H, 8.43. IR (cm-1): ν(OsH) 2127 (m); ν(BF4) 1048 (br, s). MS (MALDI-TOF): m/z 1029.6 (50), [M]. 1 H NMR (400 MHz, CD2Cl2, 293 K): δ 1.90 (m, 12H, PCH(CH3)2), 1.23 (dd, JH-H = 7.2, JH-P = 13.8, 72H, PCH(CH3)2), -9.78 (qt, JH-P = 8.1, 3H, OsH), -13.80 (t, JH-P = 29.7, 4H, OsH). 31P{1H} NMR (161 MHz, CD2Cl2, 293 K): δ 53.3 (s). 13 C{1H} NMR (75 MHz, CD2Cl2, 293 K): δ 30.0 (d, JP-C = 29, PCHCH3), 19.5 (s, PCHCH3). Structural Analysis of Complexes 2 and 6. Crystals suitable for the X-ray diffraction study were obtained by slow diffusion of diethyl ether into solutions of the complexes in dichloromethane. X-ray data were collected on Oxford Diffraction Xcalibur (2) and Bruker Smart APEX CCD (6) diffractometers using graphite-monochromated Mo KR radiation (λ = 0.710 73 A˚). For complex 2 the diffraction frames were integrated and corrected for absorption using the CrisAlys RED package.16 For complex 6 data were corrected for absorption by using a multiscan method applied with the SADABS program.17 The structures of both compounds were solved by the Patterson method. Refinement, by full-matrix least squares on F2 with SHELXL97,18 was similar for both complexes, including isotropic and subsequent anisotropic displacement parameters. The hydrogen atoms (except hydride ligands) were calculated and refined using a restricted riding model. Terminal hydride ligands were observed in the difference Fourier maps and refined with a restrained Os-H bond length (1.59(1) A˚, CSD). Bridging hydride ligands in complex 6 were observed in the difference Fourier maps and their positions fixed. The BF4 anions in both complexes were observed to be disordered. The anions were
defined with two moieties, complementary occupancy factors, isotropic atoms, and restrained geometry. In all complexes, all the highest electronic residuals were observed in close proximity of the Os centers and make no chemical sense. Crystal data for 2: C25H51BF4OsP2, Mw 690.61, colorless, block (0.25 0.08 0.04), triclinic, space group P1, a = 8.5710 (3) A˚, b = 10.5741(5) A˚, c = 15.5455(5) A˚, R = 79.513(3)o, β = 84.033(3)o, γ = 88.269(3)o, V = 1377.77(9) A˚3, Z = 2, Dcalcd = 1.665 g cm-3, F(000) = 696, T = 150(2) K, μ = 4.783 mm-1, 26 522 measured reflections (2θ = 4-58°, ω scans 0.3°), 6258 unique reflections (Rint = 0.0391), minimum/maximum transmission factors 0.7557/1.0904. The final agreement factors were R1 = 0.0290 (5312 observed reflections, I > 2σ(I)) and wR2 = 0.0596, with 6258/21/306 data/restraints/parameters and GOF = 0.975. The largest peak and hole were 2.940 and -1.125 e/A˚3. Crystal data for 6: C36H91BF4Os2P4, Mw 1115.18, orange, block (0.10 0.04 0.03), monoclinic, space group C2/c, a = 17.140(4) A˚, b = 15.568(4) A˚, c = 17.737(4) A˚, β = 99.757(4)o, V = 4665(2) A˚3, Z = 4, Dcalcd = 1.588 g cm-3, F(000) = 2240, T = 100(2) K, μ = 5.619 mm-1, 20 878 measured reflections (2θ = 4-58°, ω scans 0.3°), 5728 unique reflections (Rint = 0.0497), minimum/maximum transmission factors 0.554/0.791. The final agreement factors were R1 = 0.0310 (4313 observed reflections, I > 2σ(I)) and wR2 = 0.0497, with 5728/8/232 data/ restraints/parameters and GOF = 0.827. The largest peak and hole were 1.482 and -1.321 e/A˚3.
(16) CrysAlis; RED. A Program for Xcalibur CCD System X-ray Diffraction Data Reduction; Oxford Diffraction, Oxford, U.K., 2005. (17) Blessing, R. H. Acta Crystallogr. 1995, A51, 33. SADABS: AreaDetector Absorption Correction; Bruker-AXS, Madison, WI, 1996. (18) SHELXTL Package v. 6.10; Bruker-AXS, Madison, WI, 2000. Sheldrick, G. M. Acta Crystallogr. 2008, A64, 112.
Supporting Information Available: CIF files giving data for the X-ray analysis and crystal structure determination, including bond lengths and angles, of compounds 2 and 6. This material is available free of charge via the Internet at http:// pubs.acs.org.
Acknowledgment. Financial support from the MICINN of Spain (project numbers CTQ2008-00810 and Consolider Ingenio 2010 CSD2007-00006) and the Diputaci on General de Arag on (E35) is acknowledged. K.G. thanks the Spanish MEC for a grant.
