Organometallics 1996, 14, 1700-1711
1700
Isomers of SnPh2(BsHg)2: Synthesis and Characterization of p,p'-SnPh2(BsH&, p,2'-SnPh2(B5Hg)2, and p, 1'-SnPh2(B5H8)2 Hong Fang, Dong Zhao, Nigam P. Rath, Lee Brammer, and Lawrence Barton* Department of Chemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121 Received November 16, 1994@ The reaction between K[B5Hs]and SnCl2Ph2 in a 2:l molar ratio affords either p,p'-SnPhe(B5H8)2(11,pu,2'-SnPh2(BsH&(2), or p,l'-SnPhz(B~H&(3) depending on the choice of solvent and conditions, 1 is formed if the reaction is carried out in the noncoordinating solvent CH2Cl2 a t -35 "C, whereas if the coordinating solvents Et20 or THF are used, the products are 2 and 3, respectively. 2 is also formed when 1 is treated with Et20, and 3 is formed when 1 is treated with THF. The species are characterized by IH, llB, 13C, and '19Sn NMR spectra. The crystal structures of all three isomers are reported. 1 crystallizes in the orthorhombic space group Pna21, with a = 7.708(4) b = 15.836(6) c = 15.814(5) and 2 = 4 , 2 crystallizes in the monoclinic space group C2/c, with a = 38.506(14) b = 11.379(2) c = 19.096(6) p = 106.12(2)",and 2 = 16, and 3 crystallizes in the monoclinic space group P2Jc, with a = 9.662(2) b = 9.868(2) c = 21.009(4) p = 92.07(2)", and 2 = 4. 3 is also prepared in the reaction between K[B5Hsl and l-(SnClPh2)BbHs. If the reaction between K [ B & , ] and SnC12Ph2,in a 2:l mole ratio, is carried out in THF, two isomers of 3 appear t o be formed. 1-3 are the first structurally characterized examples of pentaboranyl(9) cages linked by a single heteroatom, and they differ only in the mode of attachment of the two B5H8 cages to the tin atom. In all three species, the Sn atom has approximately tetrahedral coordination with one cage bonding the tin atom through a three-center bond to two adjacent basal borons and the other cage bonding a similar bridging position in 1,bonding to a basal boron atom of the second cage in 2 and bonding to the apical boron atom in 3.
A,
A,
A,
A,
Introduction
Examples of borane clusters linked by single heteroatoms are quite rare. The large cage systems [Cu(lBi0HgN2)21-,~[Pd(Bi0Hi2)21~-,~" [Pt(BioH12)21~-,~~ [Au(BloH13)21~-,~ [Au(BloH12)21-,~[Zn(BloH12)21~-,~" and ( B I o H ~ ~ have ) ~ O all ~ ~ been characterized by crystal structure determinations. Three systems based on hexaborane(l0) are known. They include Mg(B~Hg12(THF)$" and Pt(BsHl0)2C12,~ for which structures are also available, and c d ( B ~ H d 2 ~ which " was identified spectroscopically. There are two reports for pentaboranyl(9) cages, one involving H g W 7 and the other involving Si and Ge.8 In both cases, the species were characterized by low-field NMR spectroscopy. We recently described the characterization of a series of tris(organyllstannyl-substitutednido-penta- and hexaboAbstract published in Advance ACS Abstracts, March 15, 1995. (1)Ng, L.-L.; Ng, B. K.; Shelly, K.; Knobler C. B.; Hawthorne, M. F. Inorg. Chem. 1991,30, 4278. ( 2 )( a ) Macgregor, S.A,; Scanlan, J. A,; Yellowless, L. J.; Welch, A. J. Acta. Crystallogr. 1991,C47, 513. (b) Macgregor, S. A,; Yellowlees, L. J.; Welch, A. J. Acta Crystallogr. 1990,C46, 1399. (3) Wynd, A J.; Welsh, A. J. J . Chem. Soc., Chem. Commun. 1987, 1174. (4) (a, Greenwood, N. N.; McGinnety, J. A.; Owen, J. D. J . Chem. SOC.A 1971,809. (b) Greenwood, N. N.; McDonald, W. S.; Spalding, T. R. J . Chem. SOC., Dalton Trans. 1980,1251 (5J(a) Denton, D. L.; Clayton, W. R.; Mangion, M.; Shore, S.G.; Meyers, E. A. Inorg. Chem. 1976,15, 541. (b) Remmel, R. J.; Denton, D. L.; Leach, J. B.; Toft, M. A,; Shore, S. G. Inorg. Chem. 1981,20. 1270. (6) Brennan, J. P.; Schaeffer, R.; Davison, A.; Wreford, S. S. J . Chem. Soc., Chem. Commun. 1973,354. (7) Hosmane, N. S.; Grimes, R. N. Inorg. Chem. 1979,18, 2886. ( 8 ) Gaines, D. F.; Ulman, J. Inorg. Chem. 1974,13, 2792. @
A,
A,
A,
A,
A,
r a n e ~ ( 9 ) We . ~ now report that selection of solvent and conditions allows individual isolation of three of the six possible linkage isomers of SnPh2(B5&)2, and we also describe the crystal and molecular structures of p,p'SnPhdBsHsh (11,pu,2'-SnPh2(B5H&(21, and p,l'-SnPhz(B5Hd2 (3). A preliminary report of some of this work has appeared.1° Experimental Section Materials. B5H9 was obtained from laboratory stock and distilled on the vacuum line before use. SnClPhs was obtained from Aldrich and used without further purification and SnC12Phn was prepared as reported in the literature." KH, obtained as a 20-25% mineral oil suspension from Alfa, was washed repeatedly before use with anhydrous pentane on the vacuum line until it was a free-flowing white powder. The activity of the powder, in reactions with methanol, was 85-95%. ~~ l-(SnClPhZ)BjHswas prepared as described p r e v i o ~ s l y .THF and diethyl ether were dried over LiAlH4, distilled from N d benzophenone ketyl, and stored over it. CHZC12 was dried and distilled over PzO5. Men0 was stirred over LiAlH4 at -78 "C for several days and distilled on the vacuum line into a storage vessel. Pentane was dried over CaHz, distilled from N d benzophenone, and stored over it. All solvents were reagent grade and were dried and distilled prior t o use and stored in Pyrex vessels with Teflon stopcocks. ( 9 ) ( a ) Barton, L.; Srivastava, D. K. J. Chem. Soc.,sDalton Trans. 1992,1327. (b) Srivastava, D. K.; Rath, N. P.; Barton, L. Organornetallics 1992,II, 2263. (c)Srivastava, D. K.; Barton, L. Organometallics 1993,12, 2864. 110JFang, H.; Zhao, D.; Brammer, L.; Barton, L. J . Chem. SOC., Chem. Commun. 1994,1531. (11)Gilman, H.; Gist, L. A. J . Org. Chem. 1957,22, 368.
0276-733319512314-1700$09.00/0 0 1995 American Chemical Society
Table 1. N M R Data for Bis(pentaborany1)diphenylstannanes compd p,p'-SnPhz(BsHx)#
pu,2'-SnPhz(B~H&'
I
'BO
IH{ "B)"
Hh
I
-7.4 Id, 4B, B(4,5), B(4',5'), 'J("B-'H) = 155 Hz] -10.8 [d, 4B, B(2,3), B(2',3'), 'J("B-'H) = 155 Hz] -45.8 [d, 2B. B(I), B(1'). 'J(l'B-'H) = 176 Hz]
-2.72 [s, br, 4H, HJ3.4). H,(2,5), HJ3',4'), H/,(2',5')] -1.98 [s, br, 2H, HJ4.5). H,(4',5')] 0.9O[q, br,2H,H(1),H(1'),J(11B-1H)= 180Hz1 1.5-3.7 [m,br, 8H, (Hl(2-5), Ht(2'-5'), JunmJ 7.34 [m, 6H, p-. m-C&] 7.45 [m, 4H, o-ChHs]
-2.6 (d, IB, B(4'), J("B-'H) = 164 Hz] -6.8 [d, 28, B(3',5'), IJ(IIB-'H) = 155 Hz] -8.2 [d, 2B, B(4.3, IJ(IIB-IH) = 164 Hz] -10.8 [d, 2B, B(2Jh J u m J - 10.5 [s, IB, B(2')] -48.0 [d, 2B, B(I), B(1'). 'J(''B-lH)= 177 Hz]
-2.75 [s, br, 2H, H,(3,4). H,,(2,5)1 -2.0 [s, br, 3H. H,(4,5), H,,(2',3'), HJ2'S')l - 1.70 [s, br, 2H, H,(3',4'), H,(4',5')] 0.85 [q.br, I H , H ( l ) , J ( l l B - l H ) = 176HzI 0.65 [q, br, IH,H(l),orH(I'),J("B-'H)= 176Hz1 1.5-3.8 [m. br, 7H, Hl(2-5), H,(3'-5'), J U 4
0.90 [s, 2H, H( 1), H( I')] 2.67 [s, 4H, H,(4,5), H,(4',5')1 2.75 [s, 4H, Hi(2,3), Ht(2',3')1 -2.25 [s, IH, H,(4,5)] -2.00 [s, 2H, H,(2',3'), Hl,(2',5')] 0.85 [s, IH,H(I)orH(I')] 0.65 [s, IH,H(I)orH(I')] 2.37 [s, 2H, H,(4,5)] 2.52 [s, 2H, Ht(2,3)] 2.73 [s, 2H, Ht(3',5')] 2.80 Is, IH, H,,(4')]
I3C{lH}< 144.7 [S, i-C&] 135.0 [s, o-CbHs, 2J(11YSn-13C) = 44 Hz] 129.8 [s,p-CbH~,4J(119Sn--"C)= 14 Hz] 129.2 [s, m-CbHs, 3J(1'9Sn-'3C) = 63 Hz]
139 I S , br, i-C6Hs] 135.8 [s, o-C6Hs, ZJ(11ySn-13C) = 42 Hz] 128.8 [s,P-CBHS.4J(11ySn-13C) = 12 Hz] = 54 Hzj 128.5 [s, rn-ChHs, 3J(119Sn-1ZC)
7.30 [m. 6H, p-. m-CsHs] 7.48 [m. 4H, o-ChHs] p,l'-SnPh2(BsH&"
-10.1 [d, br, with a shoulder 8B, B(2-5). 8(2'-5'), 'J("B-'H) 156 Hz] -48.2 [d, IB, B(1), 'J("B-'H) = 171 Hzl -51.6 [s, IB, B(1'). lJ(llB-ll"Sn) = 1 174 Hz]
I'
-2.75 1s. br, 2H. H,(3,4), H,(2,5)1
141.4 [q. i-CbH6, 2J("C-11B) = 10.2 Hz]
-2.15 [s, br, with a shoulder, 5H, H,(2',3'), H,(3',4'), H,(4',5'), H,(2',5'), shoulder H,(4,5)] 0.60 [q. br, IH, H(1), J('B-IH) = 175 Hz] 1.4-3.5 [m. br, 8H, basal HI] 7.31 [m, 6H, p - . m-CbHs] 7.46 [In,4H, f)-CsHs]
-2.35 [s, IH, H,(4,5)]
136.1 [s, o-CbHs. ZJ(llySn-l'C)= 44 Hz]
-2.08 [s, 4H, H,(2'-5')] 0.60 Is, IH, H(I)] +2.34 [s, 2H, Ht(4,5)] 2.49 [s, 2H, H,(2,3)] 2.58 [s, 4H, basal HI,]
128.6 [s,p-CbHs, 4J(119Sn-13C) = 13 Hz] 128.3 [s, m-C6Hs, 7J(11ySn-'3C)= 58 Hz]
Spectra observed at 96.3 MHz. Spectra observed at 500 MHz. Spectra observed at 76.6 MHz. In CDCIJ at 25 "C. "B spectra observed in (C2H~)20;IH spectra observed in CDCI3. I'
2: ? k (0 (0
ch
1702 Organometallics, Vol. 14,No. 4, 1995
Fang et al.
Table 2. Summary of Crystallographic Data for 1-3 2
3
C I Z H Z I~& B 397. I colorless needles 0.3 x 0.2 x 0.2 orthorhombic Pna2 I
c I ? H d 3ioSn 397. I colorless rectangles 0.35 x 0.30 x 0.20 monoclinic c2/c
C12Hx,BloSn 397.1 colorless cubes 0.45 x 0.40 x 0.30 monoclinic P2 II C
7.708(4) 15.836(6) 15.81 4 0 ) 90 1930.3(14) 4 1.366 0.71073 w-20 3.97-29.30 3.0-65.0 125(5) 1.312 0.03( 10)" 3618 3618 2062 ( F > 4.0a(F')) X W ( F " 2 - Fc?) 7.90 15.63R(F?) 1.046S(F?)
38.506( 14) 11.379(2) 19.096(6) 106.12(2) 8038(4) 16 1.313 0.71073 w-2e 4.99-29.30 3.0-55.0 125(5) 1.260 NIA 9903 9291 (R,,, = 1.58%) 6442 ( F > 4.0(F))
9.622(2) 9.868(2) 21.009(4) 92.07(2) 1993.6(7) 4 1.323 0.71073 w-26 3.50-29.30 3.0-55.0 184(5) 1.270 NIA 5162 4609 (R,,, = 2.38%) 3813 ( F 4.0@)) I N V , - Fc) 2.56 2.57 1.41
1
empirical formula fw cryst color and habit cryst size. mm cryst syst space group unit cell dimens a, A
h. c,
4
A
Z . moleculeslcell &ai& Mg m-' wavelength, 8, scan type scan sp in w (min, max), deg min-' 20 range. deg
T, K abs coeff, mm-' abs structure no. of rflns collected no. of ind reflns no. of obsvd reflns function minimized final R(F), % final wR(F)% ' goodness of fit, S ( F ) 'I
3.12 1.15
Flack parameter (SHELXL-93).
Apparatus. Standard high-vacuum line and drybox techniques were employed in this work.l2 NMR spectra were obtained on a Varian XL-300 spectrometer operating at 300.1, 96.3, 76.6, and 111.7 MHz t o observe 'H, llB, 13C,and '19Sn resonances, respectively. 'H and lH{"B} spectra were also recorded on a 500 MHz Bruker AJ3.X-500 NMR spectrometer. Assignments were confirmed by selective decoupling experiments and heteronuclear 2D llB-lH correlation spectra also run on the Bruker 500 MHz spectrometer. llB chemical shifts are reported in ppm, positive signs denoting a shift at a lower field with respect to EtzO.BF3 reference (0.0 ppm). 'H and 13C chemical shifts were measured relative to SiMe4 and CDC13, respectively. l19Sn chemical shiffs were obtained with respect to SnMe4 (0.0 ppm) as an external reference. Mass spectra were run as solids at 70 eV on a V a r i d a t 311A spectrometer equipped with a Technivent data system. IR spectra were run as KBr pellets on a Perkin-Elmer 1604 FT-IR spectrometer. Elemental analyses were performed by Atlantic Microlabs Inc. Preparation of p,p'-SnPh2(BsH&(1). KH (150 mg, 3.75 mmol) was placed in a 50 mL two-neck flask with one neck fitted with an extractor and the other neck stoppered. After evacuation, 0.4 mL of B5H9 (4mmol) and 10 mL of Me20 were condensed in at -198 "C. The mixture was warmed to -78 "C and stirred for 2 h. H2 was pumped away at -196 "C, and the solvent was removed by evacuation overnight at -78 "C to afford solvent-free U B ~ H B ICH2C12,lO . mL, was condensed onto the K[B5Hel, and under positive NZflow, a side-arm tip tube containing SnClzPhz (510 mg, 1.5 mmol) was attached t o the second neck of the reaction flask. After evacuation, the solution was stirred, the SnClzPhz was added at -78 "C, and the resulting mixture stirred at -35 "C for 4 h. The reaction mixture was allowed t o stir at -78 "C overnight and then warmed slowly over a period of 1 h to room temperature, stirred for an additional 1h, and filtered at room temperature to remove KC1 and unreacted K[B5He]. The resultant clear filtrate was reduced to 2 mL under vacuum. Addition of 10 mL of pentane resulted in a trace of precipitate; so the solvent was removed and the residue dried under vacuum for 1 h at 25 "C to afford a waxy-white solid in 60% yield. The crude (12) Shriver, D. F.; Drezdon, M. A. The Manipulation ofAir-Sensitive Compounds; John Wiley: New York, 1986.
Table 3. Atomic Coordinates ( x 104) and Equivalent Isotropic Displacement Parameters (A2x 103) for 1 X
V
Z
4652( 1) 2222(24) 3863(23) 2398(21) 558(22) 2097(20) 6498(29) 6742(24) 4949(20) 6432(24) 8 15 l(29) 31 1l(16) 1732(16) 813( 18) 1247(17) 2672( 19) 3551( 15) 6537( 16) 6493( 17) 7710(19) 9036( 18) 9 106(19) 7848( 19)
5 126(1) 3254(9) 395 I ( 11) 3992(9) 3963( 13) 3882( 1 1) 6822( 12) 6218( 1 1) 6100(11) 60 l5( 12) 6085( 16) 5940(9) 6411(8) 6949(9) 7007(8) 6529(9) 6004(7) 4454(8) 3605(8) 3173(10) 36 1O( IO) 4463( IO) 4905(9)
5000 4 121( 12) 4052( 11) 488 1( 13) 4 161(14) 3304( 13) 3579( 13) 4460( 11) 3748( 11) 2896( 11) 3632( 12) 5796( IO) 5484(9) 6020( IO) 6857( 10) 7 173(9) 6644(9) 5735(7) 5818(9) 6309( IO) 669 I ( 8) 66 17(9) 6 140(9)
WeqY
I' U(eq) is defined as one-third of the trace of the orthogonalized U j, tensor.
product may be purified by recrystallization from hexane to afford white crystalline needles. Crystals suitable for X-ray diffraction are obtained by slow evaporation of hexane solutions. 1 melts with decomposition at about 98 "C and is very soluble in THF, CHZC12, and CHC13 and sparingly soluble in C5H12, CSH14, and Et2O. Attempts to obtain satisfactory elemental analysis were unsuccessful, probably due to the high sensitivity t o air and moisture. Anal. Calcd for Cl~H26B&n: C, 36.31; H, 6.62. Found (1): C, 35.20; H, 6.14. Found (2): C, 35.11;H, 6.18. However mass spectral data were supportive of the formulation. The data for the (M - B5Hd+ ion PB51Z4Sn1*C,+H~4]+ were selected since the molecular ion [11B1~124Sn1ZC121H31]+, although quite visible with a cutoff at m / z 405, was weak. The observed m / z values for the (M - B5He)+ion (relative intensity) were 327 (1.06),328 (2.36),329 (3.18), 330
Organometallics, Vol. 14,No.4, 1995 1703
Isomers of SnPhdB&& Table 4. Atomic Coordinates ( x 104) and Equivalent Isotropic Displacement Coefficients x 103) for 2
(Az
3436( 1) 2886(2) 2908( 1) 3269( 1 ) 3253(2) 2886(2) 4 144(1) 4012( 1) 4247( 1) 4590(2) 4357(2) 3 2 9 3 1) 3559( 1 ) 3471(2) 31 15(2) 2848(2) 2936(1) 3233( I ) 3004( I ) 2851(1) 2926( I ) 3 154(I ) 3308( I ) 914(1) 437(1) 423(1) 802(2) 822(2) 435(2) I64 1( 1) Mol( 1) 1788(1) 2087( 1) 1804(2) 760( 1) 1018(1) 911(1) 549( I ) 292(1) 394( I ) 715(1) 514(1) 3 9 3 1) 476(1) 669( 1) 796( 1 )
8038( I ) 10298(5) 9327(5) 9515(5) 11092(5) I0903(5 ) 9899(4) 8608(4) 9743(5) 9804(5) 8687(5) 6456(4) 5652(4) 4638(4) 4423(4) 5212(5) 6229(4) 7965(4) 7071(4) 7058(4) 7966(4) 8873(4) 8871(4) 618(1) 2911(5) 1962(5) 2036(5) 36 1 4 0 ) 3546(5) 2458(5) 1091(4) 1937(5j 2222(5) 1376(5) - 1014(3) - 1850(4) -2927(4) -3 163(4) -2343(4) - 1280(4) 633(4) -321(4) -333(5) 594(5) 1536(5) 1562(4)
668( 1) 1344(3) 685(3) 1486(3) 1348(4) 539(3) 692(3) 984(3) 1599(3) 1130(3) 51 l(3) 1127(2) 1457(3) 1777(3) 1760(3) 1432(3) I 1 15(3) -499(2) -836(2) -1588(3) -2003(3) - l677(3) -929(3) 715(1) 1549(3) 855(3) 1639(3) 155 l(3) 754(3) 880(3) 1013(3) 1741(3) 1189(3) 458(3) 109l(2) 1425(2) 1653(3) 1558(2) 1227(3) 993(3) -454(2) -823(3) - 1578(3) -1978(3) -1623(3) -862(3)
"Equivalent isotropic U defined as one-third of the trace of the orthogonalized U,,tensor.
(6.15), 331 (24.051, 332 (46.681, 333 (72.511, 334 (87.221, 335 (loo), 336 (92.701, 337 (68.451, 338 (19.121, 339 (14.951, 340 (13.111,341 (10.631, and 342 (1.33). The calculatedlS m l z data were 327 (2.801, 328 (3.751, 329 (5.251, 330 (6.691, 331 (21.541, 332 (49.771, 333 (77.131, 334 (93.801, 335 (loo), 336 (92.191, 337 (79.001, 338 (20.021, 339 (15.431, 340 (13.691, 341 (11.89), and 342 (2.32). The IR spectrum showed the following absorbances (cm-'1: 3061 (w), 2969 (w), 2592 (s, br), 1831 (w, br), 1478 (m), 1428 (m), 1261 (s), 1085 (s, br), 1067 (s1, 1020 (s), 997 (m), 933 (m), 884 (m), 802 (s), 727 (61, 695 (s), 6107 (m), 444 (m1. Preparation of p,2'-SnPhz(B5H& (2). A two-neck reaction vessel attached to an extractor was charged with 170 mg of KH (4.25 mmol) in the drybox. After evacuation of the vessel on the vacuum line, 0.5 mL of B5H9 (4.8 mmol) and 15 mL of Et20 was condensed in a t -196 "C. Deprotonation, under continued stirring, was carried out at -78 "C overnight. The H2 was pumped away at -196 "C, and under positive nitrogen flow, the vessel was sealed with a tipper tube (13)Program for the calculation of isotopic distributions from molecular formula: Stolz, W.; Korzenioski, R. W. In lntroduction to Organic Spectroscopy; Lambert, J. B., Shurvell, H. F., Lightner, D. A,, Cooks, R. G., Eds.; Macmillan: New York 1987, pp 401-406.
Table 5. Atomic Coordinates ( x lo4) and Equivalent Isotropic Displacement Coefficients (A2x 103) for 3 Sn
W11) B(12) B(13) ~(14) B(W B(21) B(27-1 B(23) B(24) B(25) C(11) (312) (213) C(14) C(15) C(16) C(2 1) C(22) C(23) ~(24) C(23 C(26)
X
v
3500( 1) 1881(3) 2140(3) 2905(3) 1249(3) 467(3) 5500(3) 5803(3) 6396(4) 7175(3) 6560(3) 2056(2) 1006(3) 142(3) 303(3) 1332(3) 2203(3) 3666(3) 2550(3) 2698(3) 3984(3) 5100(3) 4943(3)
5756( I ) 8018(3) 7695(3) 6687(3) 650 l(3) 7.5334) 6705(3) 8 168(3) 7909(4) 6331(4) 6600(4) 5699(3) 4727(3) 4675(3) 5580(4) 6550(3) 6607(3) 37 12(3) 2986(3) 1658(3) 1025(3) 171'1(3) 3053(3)
WeqY 1427(1) 137(1j 920( I ) 342( I ) -76(2) 521(2) 1697(1) 2097(2) 1312(2) 1567(2) 2353(2) 2189( I ) 2217( I ) 273 I(2) 3223(2) 3203(2) 2690( I ) 1091(I ) 824( I ) 629( 1) 698(1) 962( I ) 1157(1)
2% 1) 3X1) 331) 32( 1 ) 3% I ) 43( 1) 31(1) 40( 1) 46(1) 47(1) 42(1) 29( 1) 37(1) 47(1j 52(1) 4% 1) 38( 1) 2% 1) 3 7 1) 3% 1) 3% 1) 38(1) 32( 1)
('Equivalent isotropic U defined as one-third of the trace of the orthogonalized U,, tensor.
containing SnClzPhz (645 mg, 1.9 mmol). SnClzPhz was added to the borane anion, the mixture was allowed to warm t o -78 "C, and the resulting suspension was stirred at -78 "C overnight. The reaction mixture became very viscous; so an additional 10 mL of Et20 was added and the mixture stirred at -78 "C for 3 h, then at -35 "C for 4 h, and at ambient temperature for 15 min. The contents of the flask were filtered at -78 "C to remove KC1 and excess K[B5Hsl and the colorless filtrate was evaporated t o dryness, resulting in 480 mg, or a 65% yield, of waxlike white solid product which on recrystallization from hexane gave colorless crystals. Crystals suitable for X-ray analysis were grown by slow evaporation from hexane. 2 melts at 74-76 "C and has solubility properties similar t o those of 1. NMR spectra are given in Table 1. 2 is most easily identified by its l19Sn NMR spectrum, which gives a broad 1:l:l:l quartet at 6 = -138.5 ppm (lJ(llgSn-llB) = 900 Hz). Mass spectral data, observed for the (M - B5Hs)+ ion, [11B,:24Sn12Cs1H~41+, were m l z (relative intensity) 327 (6.041, 328 (0.001, 329 (8.821, 330 (8.431, 331 (22.401, 332 (48.771, 333 (81.941, 334 (95.531, 335 (loo), 336 (96.351, 337 (74.73), 338 (22.611, 339 (17.591, 340 (15.591, 341 (17.59),and 342 (5.67). The calculated m l z data are the same as for 1. The IR spectrum showed the following absorbancies (cm-'): 3058 (w), 2966 (w), 2589 (s, br1, 1815 (w, br), 1479 (w), 1429 (m), 1262 (s), 1085 (s, br), 1073 (s), 1020 (s), 997 (m), 943 (w), 917 (w), 884 (m), 802 (s), 728.2 (s), 696 (s), 658 (w), 614 (m). Preparation of p,l-SnPhz(B5H&(3). l-(SnPh2Cl)B5Ha(2 mmol) in 20 mL of CH2C12, was allowed to react with K[B5Hsl (2.5 mmol solid, from the reaction of 100 mg of KH with 3 mmol of B5H9 in 10 mL of MezO), stirring overnight at -78 "C. The mixture was warmed to -35 "C and stirred at that temperature for 3 h and then at ambient temperature for an additional 0.5 h. A white turbid solution was obtained. The contents of the flask were filtered slowly at -78 "C in a vacuum extractor t o remove KC1, and unreacted NB5Hs1, and after reduction of the volume of the colorless filtrate, 10 mL of CsHiz was added. A precipitate was not obtained so the solvent was removed under vacuum. Recrystallization from hexane afforded colorless cubic crystals in 53% yield. The initial solid residue turns from off-white to pale yellow on drying. Slow evaporation from hexane affords crystals suitable for X-ray analysis. 3 has solubility properties similar to those of 1, and it melts a t 86-88 "C. NMR spectral data are given in Table 1. 3 is easily recognized by its l19Sn NMR spectrum which gives a broad 1:1:1:1quartet at 6 = -80.1 ppm (lJ(llgSn-llB)
1704 Organometallics, Vol. 14, No. 4, 1995
Fang et al.
Table 6. Selected Bond Lengths and Bond Angles for P#'-Sflhz(BsHs)z (1) Sn-C(21) Sn-C( 11) Sn-B( 12) Sn-B(l3) Sn-B(22) Sn-B(23) B( 1 I)-B( 15) B(ll)-B(13) B( Il)-B( 12) B( I 1)-B( 14) B( 12)-B( 13) C(21)-Sn-C(I 1 ) C(21)-Sn-B( 12) C(Il)-Sn-B(12) C(21)-Sn-B( 13) C(l I)-Sn-B(13) B( 12)-Sn-B( 13) C(21)-Sn-B(22) C( 1 l)-Sn-B(22) B( 12)-Sn-B(22) B( 13)-Sn-B(22) C(21)-Sn-B(23) C(Il)-Sn-B(23) B( 12)-Sn-B(23) B( 13)-Sn-B(23) B(22)-Sn-B(23) B(15)-B(I 1)-B(13) B(15)-B(ll)-B(I2) B(13)-B(lI)-B(12) B(15)-B(I 1)-B(14) B(13)-B(11)-B(14) B(l2)-B(ll)-B(l4) B(II)-B(l2)-B(I3) B(II)-B(I2)-B(I5) B(13)-B(12)-B( 15) B(ll)-B(12)-Sn B( 13)-B( 12)-Sn B( 15)-B( 12)-Sn B(l l)-B(l3)-B(12) B(l l)-B(l3)-B(l4) B( 12)-B(13)-B(14) B(Il)-B(13)-Sn B( 12)-B( 13)-Sn B(14)-B( 13)-Sn B( ll)-B( 14)-B( 15)
Bond Distances (A) 2.143( 11) B( 12)-B(15) 2.16(2) B( 13)-B(14) 2.47(2) B( 14)-B( 15) 2.51(2) B(21)-B(23) 2.5 I(2) B(21)-B(24) 2.52(2) B(2 1)-B(22) 1.63(3) B(21)-B(25) 1.68(2) B(22) -B(25) 1.68(2) B(22)-B(23) I .7 I (2) B(23)-B(24) 1.73(3) B(24)-B(25) Bond Angles (de@ 110.7(5) B( 1 1)-B( 14)-B( 13) 97.0(5) B( 15)-B(14)-B(13) 132.0(6) B(ll)-B(l5)-B(l4) 98.9(5) B( 1 l)-B( 15)-B( 12) 95.2(5) B( 14)-B( l5)-B( 12) 40.7(6) B(23)-B(21)-B(24) 95.2(6) B(23)-B(21)-B(22) 98.0(6) B(24)-B(21)-B(22) 118.1(6) B(23)-B(21)-B(25) 155.8(6) B(24)-8(21)-B(25) B(22)-B(2 1)-B(25) 13I .9(5) 98.2(5) B(21)-B(22)-B(25) 90.4(6) B(21)-B(22)-B(23) I16.3(6) B(25)-B(22)-B(23) 41.7(5) B(21)-B(22)-Sn 98.4(1 I ) B(25)-B(22)-Sn 66.0( 10) B(23)-B(22)-Sn 61.9( 10) B(21)-B(23)-B(24) 65.4(11) B(21)-B(23)-B(22) 64.9( IO) B(24)-B(23)-B(22) 97.7(1 I ) B(21)-B(23)-Sn 59.0( IO) B(24)-B(23)-Sn 55.7( IO) B(22)-B(23)-Sn 90.4( 12) B(21)-B(24)-B(25) 129.9(12) B(21)-B(24)-B(23) 70.9(8) B(25)-B(24)-B(23) 129.0(IO) B(22)-B(25)-B(21) 59.1(10) B(22)-B(25)-B(24) 58.2( 11) B(21)-B(25)-B(24) 92.0(13) C(l6)-C(ll)-C(12) 127.5(1I ) C(16)-C(Il)-Sn 68.4(8) C( 12)-C( I 1)-Sn 127 3(11) C(22)-C(21)-Sn 55.4(10) C(26)-C(2l)-Sn
1.81(2) 1.82(3) 1.81(3) 1.67(2) 1.67(3) 1.70(3) 1.73(3) 1.72(3) 1.79(2) 1.77(3) 1.77(3) 56.9( IO) 87.7( I I ) 59.2( I I ) 58.3( 10) 89.9( 12) 63.9( 11) 64.2( IO) 95.9( 13) 93.3( 13) 6 2 . 3 12) 60.0( I I ) 60.9( 12) 57.2( 11) 89.7(12) 1 2 6 . 312) 1 2 5 . 312) 69.3(7) 58.1(10)
58.6( 10) 89.3(10) 127.4(11) 127.5(10) 68.9(7) 60.3(13) 58.1(11) 88.8(1 I ) 59. I ( 1 I ) 92.0( 13) 57.2( 12) 119.3(14) I 18.3(9) I22.4( 1 I ) 122.0( IO) I19.2( IO)
= 1174 Hz).A very weak quartet is also seen under this one at 6 = -75.8 ppm. Mass spectral data, observed for the (M BsHs)+ion, [11B5124Sn12Cs1H24]+, were m / z (relative intensity)
327 (2.60), 328 (4.061, 329 (4.441, 330 (7.20), 331 (23.321, 332 (50.05), 333 (68.781, 334 (88.421, 335 (loo), 336 (92.421, 337 (61.531, 338 (22.021, 339 (15.421, 340 (15.691, 341 (15.251, and 342 (2.65). The calculated m / z data are given above. The IR spectrum showed the following absorbancies (cm-I): 3066 (w), 2983 (w), 2596 (s, br), 1844 (w), 1603 (w), 1479 (w), 1442 (s), 1429 (SI, 1369 (s), 1351 (SI, 1310 (m), 1261 (m), 1090 (m, br), 1070 (m), 1026 (m), 942 (w), 884 (w), 802 (SI, 731.6 (m), 698 (s), 668 (w). Rearrangement of 1 in CDCb. If an NMR tube containing a sample of 1 was stored in CDC13 at ambient temperature and the NMR spectra were observed periodically, changes were noted in the IlB, 'H, and 'I9Sn spectra. The spectra were quite complex, indicative of mixtures, and only the Il9Sn spectra were easily interpreted. After 1month at 25 "C the resonance at 6 = -40.1 ppm had diminished in intensity and a 1:l:l:l quartet had grown in at 6 = -138.5 ppm, indicative of the presence of isomer 2. After 4 months at 25 "C, the original signal was much smaller and a second 1:l:l:l quartet had appeared at 6 = -80.1 ppm, indicative of the presence of isomer 3. Changes are also observed in the 'H and IlB NMR spectra which are also interpreted in terms of the slow rearrangement of 1 to 2 and then to 3.
Table 7. Selected Bond Lengths and Bond Angles for P , ~ ' - S ~ P ~ Z ( B(2) SH~Z Sn( I )-B( 12) Sn( l)-B( 13) Sn( I )-B(22) Sn( l)-C( 11) Sn( I)-C(21) B(II)-B(12) B( 1l)-B( 13) B( I 1)-B( 14) B( 1l)-B( 15) B( ll)-H( I I ) B( 12)-B( 13) B(12)-B( 15) B( 12)-H( 12) B(12)-H(125) B( 13)-B( 14) B( 13)-H(13) B( l3)-H( 134) B(14)-B(15) B( 14)-H( 134) B( 14)-H( 14) B( 14)-H(145) B( 15)-H( 125)
Bond Distances (A) 2.5 13(6) B( 15)-H( 145) 2.495(6) B( 15)-H( 15) 2.230(5) B(21)-B(22) 2.137(5) B(21)-B(23) 2.148(4) B(21)-B(24) 1.695(8) B(21)-B(25) 1.682(8) B(21)-H(21) 1.676(9) B(22)-B(23) I .686(9) B(22)-B(25) 1.095(62) B(22)-H(223) I .77 l(7) B(22)-H(225) 1.814(8) B(23)-B(24) 1.083(52) B(23)-H(223) I .235(58) B(23)-H(23) 1.812(8) B(23)-H(234) 1.137(50) B(24)-B(25) I .22 I (60) B( 24)-H( 234) 1.793(8) B(24)-H(24) 1.150(59) B(24)-H(245) 1.092(50) B(25)-H(225) I .306(55) B(25)-H(245) I .344(57) B(25)-H(25)
B(12)-Sn( l)-B( 13) B( 12)-Sn( 1)-B(22) B( 13)-Sn( I)-B(22) B(12)-Sn(l)-CII 1) B(13)-Sn( I)-C(I I ) B(22)-Sn(l)-C(I I ) B( I2)-Sn( 1)-C(2 I ) B(I3)-Sn( I)-C(21) B(22)-Sn( 1)-C(2 1 ) C( 1 I)-Sn( 1)-C(21) B~l2~-B(ll)-H(ll) B(13)-B(I I)-H(l I ) B(l4)-B(ll)-H(ll) B(15)-B(I I)-H( 11) Sn(l)-B(12)-B(11) Sn( l)-B( 12)-B(l3) Sn( I )-B( 12)-B( 15) Sn( l)-B( 12)-H(12) B(I l)-B( 12)-H(12) B( 13)-B(12)-H( 12) B( 15)-B( 12)-H( 12) Sn( l)-B( 12)-H( 125) H(12)-B(12)-H( 125) Sn(l)-B(13)-B( 1I ) Sn(1)-B( l3)-B(12) Sn( I)-B( 13)-B(14) Sn(l)-B(13)-H(13) B( 1 l)-B(l3)-H(l3) B(12)-B(13)-H(13) B(14)-B(13)-H(13) Sn( l)-B( 13)-H(134) H(13)-B(13)-H(134) B(I l)-B(l4)-H(l4) B( l3)-B( l4)-H( 14) B(15)-B(14)-H(14) H( 134)-B( 14)-H( 14) H(134)-B( 14)-H(145) H(14)-B(14)-H(145) H( 125)-B(15)-H( 145) B( 1 I )-B( l5)-H( 15) B( 12)-B( 15)-H( 15) B(14)-B(15)-H(15) H( 125)-B( 15)-H( 15) H(145)-B( 15)-H( 15) B(22)-B(2l)-H(21) B(23)-B(21 )-H(2 I ) B(24)-B(21)-H(2 1 )
Bond Angles(deg) 41.4(2) B(25)-B(21)-H(21) 125 l(2) Sn( I)-B(22)-B(21) 9 2 3 2 ) Sn( 1)-B(22)-B(23) 100.9(2) Sn( I)-B(22)-B(25) 99.9(2) Sn(l)-B(22)-H(223) 118.7(2) Sn(l)-B(22)-H(225) 88.5(2) H(223)-B(22)-H(225) 126.4(2) B(21)-B(23)-H(23) 109.8(2) B(22)-B(23)-H(23) 109.4(2) B(24)-B(23)-H(23) 127.7(27) H(223)-B(23)-H(23) 128.2(27) H(223)-B(23)-H(234) 134 2(27) H(23)-B(23)-H(234) 133.6(26) B(21)-B(24)-H(24) 126.7(3) B(23)-B(24)-H(24) 6 8 8 3 ) B(25)-B(24)-H(24) 125.3(4) H(234)-B(24)-H(24) 92.8(29) H(234)-B(24)-H(245) 129.3(32) H(24)-B(24)-H(245) 140.6(26) H(225)-B(25)-H(245) 127 3 2 6 ) B(21)-B(25)-H(25) 89.5(27) B(22)-B(25)-H(25) 107.4(37) B(24)-B(25)-H(25) 128.5(3) H(225)-B(25)-H(25) 69.8(3) H(245)-B(25)-H(25) 125.5(4) Sn( l)-C(I I)-C(12) 95.6(30) Sn( 1)-C( 1 I)-C( 16) 126.6(33) Sn(l)-C(21)-C(22) 143.7(28) Sn(l)-C(21)-C(26) 123.6(27) B(12)-H( 125)-B(15) 96.0(29) B( 13)-H(134)-8(14) 110.7(37) B(14)-H(145)-B( 15) 131 O(33) B(22)-H(223)-B(23) 131.4(27) B(22)-H(225)-B(25) 137.9(28) B(23)-H(234)-B(24) 1 13.0(38) B(24)-H(245)-B(25) 9 0 3 3 7 ) B(32)-Sn(2)-B(33) I l5.4(38) B(32)-Sn(2)-B(42) 89.2(35) B(33)-Sn(2)-B(42) 135.4(3I ) B(32)-Sn(2)-C(3 I ) 132.2(27) B(33)-Sn(2)-C(3 1) 138.0(27) B(42)-Sn(2)-C(31) 109.6(35) B(32)-Sn(2)-C(4 I ) I10.3(38) B(33)-Sn(2)-C(41) 131.7(30) B(42)-Sn(2)-C(41) 128.4(31) C(31)-Sn(2)-C(41) 130.4(30)
1.239(56) 1.122(50) 1.697(7) 1.674(7) 1.693(7) 1.689(8) 1.050(51) 1.810(7) I .802(9) 1.252(51) 1.263(57) I .79 l(9) 1.277(55) 1.086(58) 1.191(57) 1.797(8) 1.323(60) 1.091(56) 1.285(56) 1.366(58) 1.224(48) 1.130(56) 133.7(31) 121.9(3) I3 1 3 3 ) 134.0(3) 113.0(28) 114.0(24) 96.7(34) 133.6(27) 133.2(28) 135.9(28) 106.2(41) 94.1(36) 109.2(37) 130.8(28) 133.2(31) 135.6(30) 113.6(36) 95.6(35) 112.4(41) 96.2( 34) 132.1(25) 128.0(28) 140.8(28) 103.9(36) 113.3(39) 120.5(3) 120.7(3) 120.8(3) 120.5(3) 89.3(37) 99.6(48) 89.6(39) 91.4(37) 86.4(31) 90.7(33) 91.4(35) 41.5(2) 124.4(2) 91.4(2) 101.9(2) 101.8(2) I18.7(2) 92.6(2) 130.0(2) 107.8(2) 107.7(2)
Rearrangement of 1 in EtzO. A 200 mg sample of 1 was dissolved in 15 mL of Et20 at -78 "C and stirred for 2 days at -78 "C and then at ambient temperature for 1.5 h. The solution was filtered, and the colorless filtrate was evacuated until dry solid residue remained. NMR spectra of the resulting
Isomers of SnPhz(B&&
Organometallics, Vol. 14,No. 4, 1995 1705
Table 8. Selected Bond Lengths and Bond Angles for hl'-Sflhz(BsHsh (3) Sn-B( 12) Sn-B( 13) Sn-B(21) Sn-C( 11) Sn-C(2 I ) B(ll)-B(12) B(ll)-B(13) B(I 1)-B(14) B(Il)-B( 15) B( I 1)-H( 11) B(12)-B( 13) B( 12)-B( 15) B( 12)-H( 12) B( 12)-H(125) B( 13)-B( 14) B( 13)-H( 13) B(13)-H( 134) B( 14)-B( 15) B( 14)-H( 134) B( 14)-H( 14) B( 14)-H( 145) B( 15)-H( 125)
Bond Distances (A) 2.532 (3) B(15)-H( 15) 2.504 (3) B( 15)-H( 145) 2.197 (3) B(21)-B(22) 2.157 (2) B(21)-B(23) 2.145 (2) B(21)-B(24) I .685 (4) B(2 1)-B(25) 1.689 (4) B(22)-B(23) 1.671 (4) B(22)-B(25) 1.676 ( 5 ) B(22)-H(22) 1.043 (31) B(22)-H(223) 1.752 (4) B(22)-H(225) 1.795 (4) B(23)-B(24) 1.100 (29) B(23)-H(234) 1.298 (30) B(23)-H(223) 1.801 (4) B(23)-H(23) 1.015 (30) B(24)-B(25) 1.249 (30) B(24)-H(234) 1.803 ( 5 ) B(24)-H(24) 1.221 (30) B(24)-H(245) 1.039 (30) B(25)-H(25) 1.288 (30) B(25)-H(225) 1.265 (29) B(25)-H(245)
B(12)-Sn-B( 13) B( 12)-Sn-B(21) B(13)-Sn-B(21) B(12)-Sn-C( 11) B( I3)-Sn-C( 11) B(21)-Sn-C( 11) B( 12)-Sn-C(21) B( 13)-Sn-C(21) B(21)-Sn-C(21) C(I 1)-Sn-C(21) B( 12)-B( 11)-H( 11) B(l3)-B(ll)-H(ll) B(14)-B(1 l)-H(lI) B(l5)-B(ll)-H(ll) Sn-B( 12)-B( 11) Sn-B(12)-B( 13) Sn-B(12)-B( 15) Sn-B( 12)-H(12) B(I 1)-B( 12)-H( 12) B(13)-B( 12)-H(12) B( W-B( 12)-H( 12) Sn-B(12)-H( 125) H(12)-B(12)-H( 125) Sn-B(13)-B(11) Sn- B( 13)- B( 12) Sn-B( 13)-B( 14) Sn-B( 13)-H( 13) B(II)-B(I3)-H(I3) B(12)-B( 13)-H( 13) B( M - B ( 13)-H( 13) Sn-B( 13)-H( 134) H( 13)-B(13)-H( 1341 B(Il)-B(I4)-H(I4) B( 13)-B(14)-H(14) B(15)-B( 14)-H(14) H( 134)-B( 14)-H( 14) H( 134)-B( 14)-H( 145) H(14)-B( 14)-H( 145) B(I I)-B(15)-H(15) B( 12)-B(15)-H(15) B( 14)-B(15)-H(15) H(125)-B(i5)-H(15)
Bond Angles (deg) 40.7(1) H(125)-B(15)-H(145) 102.8(1) H( 15)-B(15)-H(145) 104.4(1) Sn-B(21)-B(22) 89.7(1) Sn-B(21)-B(23) 1 2 3 3 I ) Sn-B(21)-B(24) 113.6(1) Sn-B(21)-B(25) 128.0( 1 ) B(21)-B(22)-H(22) 93.6( 1 ) B(23)-B(22)-H(22) 1 14.3(1) B(25)-8(22)-H(22) 106.1(1) H(22)-B(22)-H(223) 133.1(16) H(22)-B(22)-H(225) 130.0( 17) H(223)-B(22)-H(225) 129.3( 17) H(234)-B(23)-H(223) 132.4(17) B(21)-B(23)-H(23) 127.5(2) B(22)-B(23)-H(23) 68.8( I ) B(24)-B(23)-H(23) 124.8(2) H(234)-B(23)-H(23) 91.1( 15) H(223)-B(23)-H(23) 129.1(16) B(21)-B(24)-H(24) 137.3(15) B(23)-B(24)-H(24) 130.0(15) B(25)-B(24)-H(24) 9 1 3 1 3 ) H(2341-B(24)-H(24) 110.6(20) H(234)-B(24)-H(245) 129.0(2) H(24)-B(24)-H(245) 7 0 . 3 1) B(21)-B(25)-H(25) 125.1(2) B(22)-B(25)-H(25) 92.3(16) B(24)-B(25)-H(25) 128.0(17) H(25)-B(25)-H(225) 139.8(17) H(25)-B(25)-H(245) l27.7( 16) H(225)-B(25)-H(245) 92.8( 14) Sn-C( 1l)-C( 12) 110.8(22) Sn-C(II)-C(16) 131.8(16) Sn-C(21)-C(22) 135.4(16) Sn-C(21)-C(26) 1 3 4 . 316) B(13)-H(134)-B(14) 113.4(21) B( 12)-H(125)-B(15) 90.9(20) B(23)-H(234)-B(24) 110.4(21) B(14)-H(145)-B(15) 130.1(15) B(22)-H(223)-B(23) 137.1(15) B(22)-H(225)-B(25) 132.5(15) B(24)-H(245)-B(25) 114.2(20)
I . 115(29) 1.274(31) 1.691(4) 1.691(5) 1.685(4) I .689(4) 1.783 ( 5 ) 1.785 ( 5 ) 1.048 (30) 1.275 (31) 1.338 (29) 1.802 ( 5 ) 1.259 (30) 1 216 (30) 1.074 (3 I ) 1.794 ( 5 ) 1.404 (30) 1.042 (30) 1.285 (30) 1.033 (31) 1.253 (30) 1.235 (30) 89.9(19) 109.7(20) 128.8(2) 129.3(2) 134.4(2) 133.0(2) 13 l.4( 17) 130.5( 16) 137.8(17) I10.1(22) 113.9(21) 92.2( 19) 88.6( 19) 130.8(16) 1 3 5 316) 134.0( 17) 106.2(21) 112.8(22) 128.7(17) 135.4(17) 133.0(17) 113.4(21) 95.7( 18) I 1 1.2(21) 134.4( 17) 135.0(17) 135.0( 17) 106.9(22) 107.4(22) 91.3(20) 122.4(2) 119.8(2) I23.4(2) 118.8(2) 93.6( 19) 88.9( 19) 85.0( 18) 8 9 . 3 19) 91.4(21) 87.0( 18) 90.7( 19)
sample in CDC19 were identical to those observed for 2 prepared as described above and are listed in Table 1. Rearrangement of 1 in THF. An NMR sample of 1 in THF was made up at -78 "C and stored overnight. The resulting NMR spectrum indicated a mixture of 1 and 2. After 2 days the spectrum had not changed. When the sample was allowed to warm to room temperature and remain there for 1 h, the 'H and llB NMR spectra indicated the presence of only the isomer 3 and some decomposition product, most easily
Figure 1. Projection view of p,p'-SnPh2(B~H& (1). The thermal ellipsoids are at t h e 50% probability level. observed as a broad single l19Sn resonance at d = -204 ppm. The l19Sn spectrum exhibited a quartet at 6 = -75.8 ppm, suggesting that this is the minor component observed above in the preparation of 3. All other spectral data for the product mixture indicated that the major product of the reaction of 1 with THF at ambient temperature was 3. Reaction of [B~HsI-with SnClzPhz in a 2:l Mole Ratio in THF. Using the same procedure as described for the preparation of 1, except that the reaction is carried out in THF, 263 mg (37% yield) of a viscous orange residue is obtained when 610 mg of SnClzPhz (1.8 mmol) is added to K[B5H~] prepared from 0.55 mL of BbH9 (5.3 mmol) and 190 mg of KH (4.75 mmol) in 20 mL of THF. NMR spectra were identical to those for 3 except that the l19Sn spectrum exhibited two 1:l: 1:l quartets in approximately equal amounts at d = -80.1 and -75.8 ppm, suggesting that perhaps two isomers are present. X-ray Structure Determinations. Colorless crystals of 1, were obtained by slow evaporation of hexane solutions in the refrigerator at -20 "C, and 2 and 3 crystals were grown similarly in the drybox at ambient temperature. Crystals of appropriate dimensions were mounted on glass fibers in random orientations. Preliminary examination and data collection were performed using a Siemens R3mN automated single crystal X-ray diffractometer using graphite-monochromated Mo Ka radiation (A = 0.710 73 A) at 125(5)K for 1 and 2 and 184(5) K for 3. Auto-indexing of 10 centered reflections from the rotation photograph indicated an orthorhombic lattice for 1 and a monoclinic lattice for 2 and 3. Axial photographs were taken to confirm the Laue symmetry and cell lengths. Final cell constants and orientation matrices for data collection were calculated by least squares refinement of the setting angles for 20 reflections (15" < 28 < 30"). Intensity data were collected using (0-28 scans with variable scan speeds. Three representative reflections measured every 50 reflections showed
