4398
Inorg. Chem. 1994, 33, 4398-4402
Notes Anionic Tantalum(V) Bis(dicarbol1ide) Complexes with Bent-Metallocene Structures
from CaHz and stored over molecular sieves. C ~ D Z and C ~ C6DsC1 were dried over molecular sieves, and CD2C12 was dried over PzOs. TaCls (CERAC) was sublimed before use. NMR spectra were recorded on Bruker AMX-360 and AC-300 Roger Uhrhammer, Yue-Xin Su, Dale C. Swenson, and spectrometers in flame-sealed or Teflon-valved (J. Young) tubes. 'H Richard F. Jordan* and NMR chemical shifts are reported vs Me& and were Department of Chemistry, University of Iowa, determined by reference to the residual 'H and I3C NMR solvent peaks. IiB{'H} NMR spectra are referenced to external BF3.Et20 (6 0, C6D6). Iowa City, Iowa 52242 The numbering system used in the "B NMR assignments is based on Received March 30, 1994 that in Figure 1. Assignments are based on 'IB-l'B COSY data.* In some cases (noted below) expected I1B--I'B COSY correlations involving B nuclei which flank the carborane C nuclei were not Introduction observed; this phenomenon has been noted previously and has been Bis(dicarbol1ide) complexes (qS-C2B9H11)2M which adopt ascribed to diversion of s electron density away from B-B bonds to ferrocene-type metallocene structures are well-known.' HowB-C bonds.9 I9FNMR spectra are referenced to extemal CC13F (6 0, ever, (q5-C2B9H11)2MX, species with bent metallocene structures CDzC12). Elemental analyses were performed by E & R Microanalytical are comparitively rare and to our knowledge are limited to the Laboratory, Inc. (CzB9Hil)TaC13' and [ P P N ] [ T ~ ( C ~ B ~ Hwere II)]~~ prepared by literature methods. f-block metals. Key examples include Raymond's dianionic tPPNl[(CzB9H11)2TaCi21(1). A slurry of ( C Z B ~ H I I ) T(336 ~C~ mg, ~ U(1V) complex (~,7~-C2B9H11)2UC12~and a series of lanthanide 0.800 "01) and [PPN][T~(CZB~H~I)] (700 mg, 0.800 mmol) in CHzcomplexes (qs-C2B9H11)2Ln(THF)2- (Ln = Sm, Yb) prepared C ~ (100 Z mL) was prepared at -78 "C. The mixture was warmed to by H a ~ t h o r n e .Recently, ~ Hosmane has characterized a series 23 "C and stirred for 1 h. The slurry was filtered through an E porosity of {q5-2-(SiMe3)-3-(R)-2,3-C2Bfi}2M(C1)(THF)'(n = 2, Y; Schlenk frit, and the residue on the frit was washed with CHzClz (2 x n = 1, Zr, Hf) complexes which adopt bent-metallocene 10 mL). The combined filtrate and wash was evaporated to dryness structure^.^ For several years we have been investigating the and dried overnight under vacuum yielding 1 (0.824 g, 99%) as a redpossibility of exploiting carborane ligands in the construction brown oily solid. This material may be purified by dissolution in CH2of electrophilic early transition metal alkyl system^,^ and we Cl2 and reprecipitation with pentane. 'H NMR (360 MHz, CDzC12): have reported on a series of mixed-ring bent-metallocene (CS6 7.67 (m, 6 H, PPN), 7.48 (m, 24 H, PPN), 3.64 (s, 4 H, CH), 4.0M ~ ~ ( C ~ B ~ H I I ) (M M (= R Zr, ) Hf) and ( C S W ) ( C ~ B ~ H I I ) T ~ X1.5 ~ (br m, 18 H, BH). 13C{'H) NMR (CD2Clz): 6 134.0, 132.4 (vir t, J = 6 Hz), 129.8 (vir t, J = 7 Hz), 127.3 (dd, J = 109, 1.8 Hz), 62.1 (R = H, Me) specie^.^.^ During the course of this work we (CzB9Hii). llB{'H) NMR (CD2C12): 6 26.7 (B2), 2.9 (B6, B7), -4.7 prepared a series of anionic tantalum(V) bis(dicarbol1ide) (B5, B8), -5.6 (Bl, B3), -11.8 (B4), -14.4 (B9). "B-"B COSY complexes, (qS-C2B9H11)2TaX2-(X = C1 (l), Me (2), F (3)), (CD2C12) (correlations observed): B2-(B1, B3) s; B2-(B6, B7) m; which adopt bent-metallocene structures. The synthesis and (Bl, B3)-(B5, B8) m; (B6, B7)-(B5, B8) w; (B6, B7)-(B9) m; (B5, characterization of these compounds are discussed in this B8)-B9 w." Anal. Calcd for C ~ H ~ Z B I ~ C ~C, ~ 45.53; N P ~ H, T ~4.97; : contribution. C1, 6.72; N, 1.33. Found: C, 45.33; H, 5.03; C1, 6.90; N, 1.38. [PPN][(CZB~HII)ZT~M~~] (2). Method A. A solution of MeLi in Experimental Section Et20 (0.27 mL, 1.4 M, 0.38 "01, Aldrich) was added dropwise via General Procedures. All manipulations were performed on a highsyringe to a solution of [PPN][(C~B~HII)ZT~C~Z] (200 mg, 0.189 m o l ) vacuum line or in a glovebox Nz atmosphere. Toluene and pentane in toluene (40 mL). The mixture was stirred at 23 "C for 2 h. The were distilled from sodiumhenzophenone ketyl. CHzC12 was distilled resulting yellow slurry was centrifuged, and the residue was extracted with toluene (200 mL) until the remaining residue was off-white in (1) (a) Hawthome, M. F.; Young, D. C.; Andrews, T. D.; Howe, D. V.; color. The combined extract was concentrated to 125 mL and cooled Pilling, R. L.; Pitts, A. D.; Reintjes, M.; Warren, L. F., Jr.; Wegner, to -32 "C for 6 h. Filtration yielded 135 mg of 2 as yellow crystals. P. A. J . Am. Chem. SOC.1968, 90, 879. (b) Zalkin, A,; Hopkins, T. The filtrate was concentrated to 25 mL and stored at -32 OC overnight, E.; Templeton, D. H. Znorg. Chem. 1967, 6, 1911. (c) St. Clair, D.; yielding an additional 45 mg of 2. Total yield: 77%. Zalkin, A.; Templeton, D. H. J. Am. Chem. SOC.1970, 92, 1173. (d) Wing, R. M. J. Am. Chem. SOC. 1970, 92, 1187. (e) Ruhle, H. W.; Method B. A solution of MeLi in Et20 (0.14 mL, 1.4 M, 0.19 Hawthome, F. Inorg. Chem. 1968, 7, 2279. (0 Warren, L. F., Jr.; "01, Aldrich) was added dropwise via syringe to a solution of [PPNIHawthome, M. F. J. Am. Chem. SOC.1970, 92, 1157. (g) Churchill, [ ( C Z B ~ H I I ) ~ T(100 ~ C ~mg, ~ ] 0.195 "01) in toluene (40 mL). The M. R.; Gold, K. J. Am. Chem. SOC.1970,92, 1180. (h) Schubert, D. mixture was stirred at 23 "C for 2 h. The resulting slurry was M.; Rees, W. S.,Jr.; Knobler, C. B.; Hawthome, M. F. Organomeevaporated to dryness under vacuum. The crude product was dissolved tallics 1990, 9, 2938. (i) Kang, H. C.; Lee, S. S.; Knobler, C. B.; in CHZC11(10 mL), and the mixture was filtered through a frit covered Hawthome, M. F. Znorg. Chem. 1991,30,2024. (j)Callahan, K. P.; Hawthome, M. F. Adv. Organomet. Chem. 1976, 14, 145. (k) For with Celite. The Celite was washed with CH2C12 (2 x 10 mL). The related compounds, see: Salentine, C. G.; Hawthome, M. F. Znorg. combined filtrate and wash was quickly evaporated to dryness under Chem. 1976. 15. 2812. (2) Fronczek, F. R.; Halstead, G. W.; Raymond, K. N. J . Am. Chem. Soc. 1977, 99, 1769. (8) Venable, T. L.; Hutton, W. C.; Grimes, R. N. J . Am. Chem. SOC.1984, (3) Manning, M. J.; Knobler, C. B.; Khattar, R.; Hawthome, M. F. Znorg. 106, 29. Chem. 1991, 30, 2009. (9) (a) Brown, M.; Plesek, J.; Base, K.; Stibr, B. Magn. Reson. Chem. (4) (a) Oki, A. R.; Zhang, H.; Hosmane, N. S. Organometallics 1991, 1989,27, 947. (b) Fontaine, X. L. R.; Greenwood, N. N.; Kennedy, 10, 3964. (b) Siriwardane, U.;Zhang, H.; Hosmane, N. S. J . Am. J. D.; Nestor, K.; Thornton-Pett, M. J . Chem. SOC.,Dalton Trans. 1990, Chem. SOC.1990, 112, 9635. (c) Jia, L.; Zhang, H.; Hosmane, N. S. 681. (c) Hlatky, G. G.; Eckman, R. R.; Turner, H. W. Organometallics Acta Crystallogr. 1993, C49, 453. 1992, 11, 1413. ( 5 ) Jordan R. F. Adv. Organomet. Chem. 1991, 32, 325. (10) (a) Manning, M. J.; Knobler, C. B.; Hawthorne, M. F. Inorg. Chem. (6) (a) Crowther, D. I.; Baenziger, N. C.; Jordan, R. F. J . Am. Chem. 1991, 30, 3589. (b) Spencer, J. L.; Green, M.; Stone, F. G. A. J . SOC.1991,113, 1455. (b) Jordan, R. F. Makromol. Chem., Macromol. Chem. SOC., Chem. Commun. 1972, 1178. (c) See also: Jutzi, P.; Symp. 1993, 66, 121. Wegener, D.; Hursthouse, M. B. Chem. Ber. 1991, 124, 295. (7) Uhrhammer, R.; Crowther, D. J.; Olson, J. D.; Swenson, D. C.; Jordan, (11) Expected B4-(B3, B5, B9) and (Bl, B3)-(B6. B7) correlations not R. F. Organometallics 1992, 11, 3098. observed.
0020-166919411333-4398$04.50/0
0 1994 American Chemical Society
Inorganic Chemistry, Vol. 33, No. 19, 1994 4399
Notes
Q
Table 1. Summary of Crystallographic Data for [PPNI [ ( C Z B ~ H ~ Z T ~(2) M~ZI
empirical formula fw cryst size (mm) c j s t color T (K) ;P;; group b (A) c (A)
a (deg)
B (de&
Y (deg)
v (A3)
Figure 1. ORTEP view of the (v5-C2B9H11)2TaMez-anion of 2.
vacuum. The residue was recrystallized from toluene/pentane yielding 2 (69 mg, 72%). Traces of toluene in 2 can be removed by (i) dissolution of 2 in CHzClz followed by solvent removal and drying under vacuum at 23 "C for 15 h or (ii) drying under vacuum at 65 "C for 44 h. 'H NMR (CDZC12): 6 7.65 (m, 6 H, PPN), 7.50 (m, 24 H, PPN), 4.25 (s, 4 H, CH), 3.0-0.5 (br m, 18 H, BH), 1.38 (s, 6 H, Me). 13C{IH) NMR (CDzC12): 6 134.1, 132.5 (vir t, J = 6 Hz), 129.8 (vir t, J = 6 Hz), 127.4 (d, J = 109 Hz), 78.4 (Me), 60.8 ( C Z B ~ H ~ ~ ) . ''B{'H} NMR (CDzClz): 12.9 (B2), 0.1 (Bl, B3, B6, B7), -8.7 (B9), -11.1 (B5, B8), -14.4 (B4). 'IB-"B COSY (115 MHz, CDzClZ) (correlations observed): B2-(B6, B7) w; B2-(B1, B3) s; (B6, B7)(B5, B8) m; (B6, B7)-(B9) m; (B5, B8)-B9 vw.l2 Anal. Calcd for C ~ ~ H J ~ B ~ ~ ~C,\ J49.73; P Z T ~H,: 5.76; N, 1.36. Found: C, 49.64; H, 5.54; N, 1.36. [PPN][(CZB~HII)ZT~F~] (3). A mixture of 1 (292 mg, 0.276 m o l ) and Ag[PF6] (140. mg, 0.554 m o l ) in CHzC12 (50 mL) was stirred at 23 "C for 24 h and then heated at 50 "C for 30 h. The resulting yellow slurry was filtered, and the precipitate was washed with CHzClz (2 x 10 mL). The combined filtrate and wash was evaporated to dryness and dried overnight yielding a yellow oily solid 3 (285 mg, 98%). Attempts to recrystallize this material were unsuccessful. 'H NMR (CDzClZ): 6 7.67 (m. 6H, PPN), 7.50 (m, 24 H, PPN), 3.81 (s, 4 H, CH), 4.00-0.50 (br m, 18 H, BH). I3C{'H} NMR (CDzClz): 6 134.1, 132.5 (vir t, J = 6 Hz), 129.8 (vir t, J = 6 Hz), 127.4 (d, J = 109 Hz), 69.0 (CzB9Hll). I9F NMR (CDzClZ): 6 14.6. IIB{IH) NMR (CDr Clz): 6 13.2 (B2), 1.5 (B6, B7), 0.4 (Bl, B3), -7.6 (B5, B8), -10.5 (B4), - 10.6 (B9). "B-IlB COSY (CDZC12) (correlations observed): B2-(B1, B3) s; B2-(B6, B7) vw, (Bl, B3)-(B6, B7) m; (B6, B7)(B5, B8) m; (B6, B7)-(B9) m; (B5, B8)-(B4) w, (B5, B8)-B9 vw.13 Anal. Calcd for C ~ O H ~ ~ B ~ ~ F ZC,N 46.99; P Z T ~H, : 5.13; N, 1.37; F, 3.72. Found: C, 46.74; H, 4.90; N, 1.18; F, 3.62. X-ray Diffraction Analysis of 2. Single crystals of 2CHzCl2 suitable for X-ray diffraction were grown by cooling a CHzClJpentane solution of 2 at -32 "C and sealed in glass capillaries under N2. Diffraction data were obtained with an Enraf-Nonius CAD4 diffractomer, and all calculations were made using the SDP package provided with this s y ~ t e m . ' Crystallographic ~ details are summarized in Table 1. (12) Expected B4-(B5, B8, B9) and (Bl, B3)-(B5, B6, B7, B8)
correlations not observed. (13) Expected (Bl, B3)-(B5, B8) correlation not observed. B4 and B9 resonances insufficiently resolved to observe correlation. (14) Frenz, B. A. The Enraf-Nonius CAD4 SDP System. In Compuring in Crystallography; Delft University Press: Delft, Holland, 1978; p 64.
Z d&d (p/cm3) cell dimen determination 1 (Mo K a radiation, A) scan ratio ( d e ) scan limit (deg) scan speed (dedmin) w scan range (deg) data collected h; k; 1 no. of tot. reflns no. of unique reflns no. of reflns used, I -= 2a(I) Rint
max decay cor factor p, cm-' empirical abs cor range structure soln method refinementa tot. no. of params R R W
weighting coeff P,Qb SDOUW' max shift/esd max resid density (e/A3)
C~ZH~~B~SN~T~~HZC~Z 1099.36 0.36 x 0.37 x 0.23 yellow 225 P1 15.012(5) 14.777(5) 12.117(6) 90.3 l(4) 96.03(4) 79.96(3) 2632.(3) 2 1.39 24 reflns; 19 < 26' < 28 0.7107 1 2
