Organometallics 1995, 14, 20-23
20
Articles (Cyclopentadienylalky1)phosphineDerivatives of Gallium(II1) and Indium(II1) Alan H. Cowley," Christopher S. King, and Andreas Decken Department of Chemistry and Biochemistry, The University of Texas a t Austin, Austin, Texas 78712 Received May 6, 1994@ The bis(tert-buty1)phosphinoethylcyclopentadienidecomplexes [~-BuzPCHZCHZC~H~IMXZ with M = Ga, X = Cl(3); M = In, X = Cl(4); M = Ga, X = Me (5); and M = In, X = Me (6) have been prepared by the reaction of the phosphinoethylcyclopentadienide lithium salt with the appropriate group 13 chloride. Compounds 5 and 6 were also prepared by the methane elimination reactions of the phosphinoethylcyclopentadiene with MMe3. Each compound has been characterized by elemental analysis, lH, 13C,and 31PNMR, and mass spectroscopy. The structures of 4 and 5 were determined by X-ra crystallograph . Crystal data for 4: space group P212121, a = 8.782(2) A,b = 14.039(1) c = 15.116(2) V = 1863.6(9) Hi3, 2 = 4, and R = 0.0352. Crystal data for 5: space group P21/c, a = 12.653(3) A,b = 9.683(2) c = 15.313(3) p = 100.81(3)", V = 1842.8(9) A3, 2 = 4, and R = 0.0562. The X-ray analyses reveal that for both compounds (i) the M X 2 fragment is T+, attached to the cyclopentadienyl ring and (ii)the phosphorus atom is coordinated intramolecularly to the group 13 center.
1,
A,
A,
Introduction Cyclopentadienyl and phosphine ligands are ubiquitous in inorganic chemistry. Not surprisingly, therefore, the possibility of combining the special features of these ligands in a potentially chelating fashion has begun to attract attention. A few (cyclopentadienylalky1)phosphines of the general type C~%(CHZ)~PRZ (n = 1,2)have now been prepared and employed as 1igands.l However, with the exception of one trimethylstannyl derivative,la these interesting heterodifunctional ligands have been used exclusively in the context of d-block chemistry. We have therefore become interested in exploring the utility of these ligand systems for the synthesis of main group compounds. Given the considerable current interest in a variety of 13/15 ring, cage, and acyclic compounds as single-source precursors to compound semiconductors,2 we have chosen to initiate our studies by an investigation of the ligative behavior of some gallium(II1) and indium(II1) halides and alkyl^.^
Results and Discussion The reagent lithium (2-{di-tert-butylphosphinoethy1)cyclopentadienide) (1)was prepared via the reaction of Lip-t-Buzwith spiro[4.2lhepta-l,3-dieneaccording to the method of Kauffman et al.lb The corresponding cyclopentadiene 2 was prepared by hydrolysis of 1. The gallium(II1) and indium(II1) compounds 3-6 were prepared in excellent yields via the metathetical reactions of 1with the appropriate metal chlorides in THF at low temperature.
Li[ (C5H4)CH2CH2P-f-Buz1 1
X2MCl (-LiCI)
3: M = Ga; X = C1 4: M =In; X = C1 5: M = G a ; X = M e
Abstract published in Advance ACS Abstracts, November 1,1994. (1)(a) Charrier, C.; Mathey, F.J. Organomet. Chem. 1979,170,C 41. (b) KauEmann, T.; Ennen, J.; Lhotak, H.; Rensing, A.; Steinseifer, F.;Woltermann, A. Angew. Chem., Int. E d . Engl. 1980,19,328. (c) Slawin, A. M. Z.; Williams, D. J.; Crosby, J.; Ramsden, J. A.; White, C. J. Chem. Soc., Dalton Trans. 1988, 2491. (d) Szymoniak, J.; BesanGon, J.; Dormond, A.; Mofse, C. J. Org. Chem. 1990,55, 1429. (e) Kettenbach, R.T.; Butenschon, H. New J. Chem. 1990,14,599. (0 Miguel-Garcia, J. A.; Adams, H.; Bailey, N. A,; Maitlis, P. M. J. Orgunomet. Chem. 1991,413, 427. (g) Butenschon, H.; Kettenbach, R. T.; KrUger, C. Angew. Chen., Int. E d . Engl. 1992,31,1066. (2)For reviews, see: Cowley, A. H.; Jones, R. A. Angezu. Chem., Int. Ed. Engl. 1989,28,1208. Wells, R. L. Coord. Chem. Rev. 1992,112, 273. Cowley, A. H.; Jones, R. A. Polyhedron 1994,13,1149. (3) For interesting work on amine analogues, see: Jutzi, P.; Dahlhaus, J.; Bangel, M. J. Organomet. Chem. 1993,460,C13.
6: M = I n ; X = M e
@
A second synthetic strategy was employed for the synthesis of 5 and 6,
namely, the methane elimination reactions between 2 and the relevant gallium or indium trialkyl. 3-5 were obtained as colorless crystals; 4 is a white powder. Each of the new compounds is slightly air
Q276-7333/95/2314-QQ2Q~Q9,QQ~Q 0 1995 American Chemical Society
(Cyclopentadienylalky1)phosphineDerivatives of Ga(II) and In(III) c141 A
Organometallics, Vol. 14,No.1, 1995 21 Table 1. Selected Bond Distances (A)for (t-Bu8CHzCHzCfi)InClz (4) and (t-BugCHzCHzCsHdGaMe, (6)
C161 C171
In-P P-C(7) P-C(8) P-C( 12) In-C(l) In-Cl(1) In-Cl(2)
Compound 4 2.595(2) C(l)-C(2) 1.843(9) cm-c(3) 1.860(9) C(3)-C(4) 1.854(10) C(4)-C(5) 2.202(9) C(5)-C(6) 2.383(3) 2.364(3)
Ga-P P-C(7) P-C(8) P-C(12) Ga-C(l) Ga-C( 16) Ga-C(17)
Compound 5 2.493(2) C(l)-C(2) 1.839(5) cm-c(3) 1.868(6) C(3)-C(4) 1.863(7) C(4)-C(5) 2.103(5) c(1)-c(5) 1.964(6) 1.961(7)
C131
W
Cllll
c1121
Figure 1. View of [~-BUZPCH~CH~C~&II~C~Z (4) showing the atom-labeling scheme. The CH3 groups are omitted for clarity.
C131 c171
Figure 2. View of [t-BuzPCHzCH2C&blGa.M~ez(6) showing the atom-labeling scheme. The t-Bu CH3 groups are omitted for clarity.
sensitive in the solid state. The methyl derivatives 5 and 6 are distinctly more volatile than the chloro analogues 3 and 4 and sublime readily at 100 "C
Torr). Satisfactory carbon and hydrogen analyses were obtained for the indium compounds 4 and 6. However, despite several attempts, the carbon analyses for the analogous gallium compounds, 3 and 5, were found to be 3 4 % too low. This does not appear to be a consequence of the presence of impurities since both compounds have sharp melting points. Excellent HRMS data were obtained for 3-6 (Experimental Section). The 31PNMR chemical shifts for 3-6 are less shielded than those of the free ligand 2 by between 5 and 24 ppm, thus suggesting that the pendent phosphine is coordinated to the group 13 center in each case. It was not clear from NMR data, however, how the MXZmoiety is attached to the cyclopentadienyl ring because only two types of ring proton and one type of ring carbon are detectable at ambient temperature. The question of the ground state geometries of 4 and 6 was resolved by X-ray analysis. The molecular structures of 4 and 5 are shown in Figures 1 and 2, respectively, along with the relevant atom-numbering schemes. In contrast to, for example, (csHs)GaMe~,~ crystals of 4 and 5 consist of
1.452(13) 1.318(17) 1.416(5) 1.339(15) 1.509(12)
1.437(9) 1.324(10) 1.407(10) 1.370(10) 1.433(8)
Table 2. Selected Bond Angles (deg) for (t-BuZpCHzCH2Cs&)InClz (4) and (t-BuSCHzCHzCs%)GaMez (5) In-P-C(7) In-P-C(8) C(7)-P-C(8) In-P-C( 12) C(7)-P-C(12) C(8)-P-C(12)
Compound 4 103.7(3) Cl(l)-In-C1(2) 112.3(3) P-In-Cl( 1) 107.2(4) P-In-Cl(2) 111.4(3) P-In-C(l) 104.8(5) Cl(l)-In-C(l) 116.2(4) C1(2)-In-C(1)
101.9(1) 113.0(1) 111.2(1) 104.2(2) 108.2(3) 118.6(2)
Ga-P-C(7) Ga-P-C(8) C(7)-P-C(8) Ga-P-C(12) C(7)-P-C(12) C(8)-P-C(12)
Compound 5 104.5(2) C(16)-Ga-C(17) 115.2(2) P-Ga-C(16) 106.5(3) P-Ga-C(17) 113.8(2) P-Ga-C(l) 103.6(3) C(16)-Ga-C(1) 111.9(3) C(17)-Ga-C(1)
114.8(3) 110.9(2) 112.7(2) 91.3(2) 115.0(3) 109.9(2)
isolated molecules with no abnormally short intermolecular contacts. In both compounds, the group 13 MX2 fragment is attached to the cyclopentadienyl ring in an q1 fashion in an a position with respect to the phosphinoethane moiety. The patterns of bond distances (Table 1)and bond angles (Table 2) within the cyclopentadienyl ring are similar to those of other yl-metalated systems, specifically, (i) the C(2)-C(3) and C(4)-C(5) bond distances are shorter than the others, and (ii) the smallest bond angle is C(2)-C(l)-C(5). The GaC(ring) bond distance in 5 (2.103(5)A) is similar to that reported for (ql-CsH&Ga (average 2.05(2)) However, the In-C(ring) bond distance in 4 (2.202(9)A) is slightly shorter than those reported for the +attached cyclopentadienyl rings of (C5H&In (average 2.240(9) A1.6
The X-ray crystallographic studies also reveal that the phosphine arm is coordinated to the MX2 center in 4 and 5, thus confirming the 31P NMR spectroscopic indications discussed above. Both compounds therefore possess a bicyclic structure which is formed by fusion of a cyclopentadienyl and a six-membered MC4P ring. The conformations of the MC4P rings are twist-boat and boat in 4 and 5, respectively. The P Ga dative bond distance in 5 (2.493(2)A) is comparable to that in the Lewis acid-base complex Me3P GaMe3 (2.52 A).' As expected, the geometries at phosphorus and the
-
-
(5) Beachley, 0. T., Jr.; Getman, T. D.; Kirss, R. U.; Hallock, R. B.; Hunter, W. E.; Atwood, J. L. Orgunometullics 1986, 4 , 751. (6) Einstein, F. W. B.; Gilbert, M. M.; Tuck, D. G. h g . Chem. 1972, 11, 2832.
(4) Mertz, K.; Zettler, F.; Hausen, H. D.;Weidlein, J. J.Orgunomet. Chem. 1976,122, 159.
(7) Golubkinskaya, L. M.; Golubinskii, A. V.; Mastryukov, V. S.; Vilkov, L. V.; Bregadze, V. I. J. Orgunomet. Chem. 1976, 117, C4.
Cowley et al.
22 Organometallics, Vol. 14,No. 1, 1995 group 13 element are approximately tetrahedral. However, there are considerable departures from the ideal angle at both centers for both compounds. Finally, we return to the question of the implied fluxionality of 3-6 in solution. Ligand 1 is not fluxional; hence it is evidently the M X 2 moiety which shuttles back and forth between the C(1) and C(4) positions of the cyclopentadienyl ring in 3-6. Presumably, the P Ga or P In dative bond is broken concomitantly in this process. Attempts to address this question were not successful; no spectral changes other than viscosity broadening were detected upon cooling toluene or THF solutions of 3-6 to -80 "C.
-
-
Experimental Section General Considerations. All reactions were performed under oxygen-free argon or under vacuum using standard Schlenk line or drybox techniques. All solvents were dried over sodium and distilled from sodium benzophenone under argon before use. The reagents GaCl3, InC13, MesGa, MeaIn, and n-BuLi were procured commercially and used without further purification. The concentration of the n-BuLi was determined by titrimetric analysis prior t o use. Spiro[4.2]hepta-1,3-diene8 and t-BuzPHg were prepared according t o literature methods. Physical Measurements. IR spectra were obtained as KBr pellets on a Bio-Rad FTS-40 spectrometer. Mass spectra, E1 and CI, were run on a Bell and Howell 21-491 instrument, and NMR spectra were measured on a GE QE-300spectrometer (IH, 300.17 MHz; 13C,75.48 MHz; 31P,121.5 MHz). NMR spectra are referenced to CsDs and THF-cis, both of which were dried over NdK alloy and distilled prior to use. All chemical shifts are reported relative to TMS (0.00ppm). Melting points (uncorrected) were obtained in sealed capillaries under argon (1atm), and elemental analyses were performed by Atlantic Microlab, Norcross, GA. Synthesis of Lithium [2-(Di-tert-butylphosphinoethy1)cyclopentadienidel (1). A hexane solution of 1.6 M n-BuLi (62.5 mL, 0.10 mol) was added to a stirred solution of t-BuzPH (14.62 g, 0.10 mol) in 30 mL of THF at -78 "C. The stirred reaction mixture was allowed t o warm slowly to 0 "C. A THF solution of 1.13M spiro[4.2lhepta-1,3-diene(88.5mL, 0.10 mol) was then added and the solution heated to reflux for 13 h. The solution was cooled to room temperature and the solvent removed under reduced pressure. The residue was then washed with cold hexane (3 x 50 mL) and dried in vacuo t o afford 20.7 g (84.7 mmol, 85% yield) of the light tan powder 1, mp 235-237 "C. Synthesis of 2-(Di-tert-butylphosphinoethyl)cyclopentadiene (2). A stirred solution of 0.33 g (1.0 mmol) of 1in 10 mL of hexane was hydrolyzed by addition of 10 drops of water. The solution was dried over MgSOl and filtered and the solvent removed under reduced pressure to yield 0.16 g of brown oil 2,(0.5 mmol, 50% yield). IH NMR (CeDs): 6 1.06 (d, CH3, 18 H), 1.59 (m, CHZ,2 H), 2.63 (m, CHZ,2 H), 6.20 (m, ring H, 5 H); 31PNMR (C6D6): 6 29.2 (9). Synthesis of Dichloro[ 1-ql-(2-di-tert-butylphosphino)ethylcyclopentadienyllgallium (3). A solution of 0.31 g (1.2 mmol) of 1 in 20 mL of THF was added at -78 "C to a stirred solution of GaC13 (0.22 g, 1.2 mmol) in 30 mL of THF. After 3 h at -78 "C, the stirred reaction mixture was allowed to warm to room temperature. The solvent and volatiles were removed under reduced pressure. The residue was extracted with CHzClz (60 mL) and filtered, and the solvent removed under reduced pressure. The residue was then dissolved in a minimum amount of THF. A few drops of hexane were added t o aid crystallization. Colorless crystals of 3 (mp 134-135 "C)
Table 3. Crystal Data, Details of Intensity Measurement, and Structural Refinement for (t-Bu#CHzCH2CsI&)InCl* (4) and ( ~ - B u # C H ~ C H ~ C S H ~ ) (5) G~M~~ compd formula fw cryst dimen, mm cryst syst space group a, A
b, A c, A
a, deg P 3
deg
Y deg 3
v,A3
D,,I,, g cm-3 Z radiation no. of total reflns no. of obsd reflns sig test no. of param weighting scheme g in [(uF)* gFL1-1 final R final Rw
+
4 ClsH26Cl~InP 423.0 0.22 x 0.22 x 0.31 orthorhombic E12121 8.782(2) 14.039(1) 15.116(2) 90.0 90.0 90.0 1863.6(9) 1.508 4
5
Ci7H3zGaP 337.1 0.31 x 0.53 x 0.60 monoclinic E1lc
2318 1881 F >W F ) 174 0.0005
12.653(3) 9.683(2) 15.313(3) 90.0 100.81(3) 90.0 1842.8(9) 1.215 4 Mo Ka 3234 2116 F > 4a(F) 172 0.0005
0.0352 0.0395
0.0525 0.0562
Mo Ka
formed upon cooling this solution t o -20 "C for 12 h. IH NMR (CsDs): 6 0.99 (d, CH3, 18 H), 1.46 (m, CH2, 2 H), 2.52 (m, CH2,2 H), 5.14 (8, ring H, 2 H), 6.78 (s, ring H, 2 HI; 31PNMR (CsD6): 6 8.3 ( 8 ) . MS(C1) 379 [M-1. HHkfS calcd 377.048 326, found 377.047 549. Anal. Calcd for C ~ ~ H Z ~ C ~C, Z 47.66; G~P: H, 6.95. Found: C, 44.34; H, 6.61. Synthesis of DichloroL l-q1-(2-di-tert-butylphosphino)ethylcyclopentadieny1lindium(4). A solution of 1.32 g (5.4 mmol) of 1 in 20 mL of THF was added at -78 "C to a stirred solution of InC13 (1.19 g, 5.4 mmol) in 30 mL of THF. After 3 h at -78 "C, the stirred reaction mixture was allowed to warm to room temperature. The solvent and volatiles were removed under reduced pressure, and the residue was extracted with toluene (3 x 60 mL). The mixture was filtered to separate the product 4 from LiCl and unreacted starting materials. The solvent was removed under reduced pressure. The resulting residue was dissolved in 5 mL of CHzC12. Several drops of hexane were added t o aid crystallization. Colorless crystals of 4 (mp 194 "C) formed upon cooling this solution to -20 "C for 12 h (3.8 mmol, 70% yield). IH NMR (CsDs): 6 0.88 (d, CH3, 18 H), 1.34 (m, CHZ,2 HI, 2.40 (m, CHZ,2 H), 5.40 (s, ring H, 2 H), 6.74 (s, ring H, 2 H). 13CNMR (C6Ds): 6 26.8 (d, CHz, 'J(CP) 1.7 Hz), 28.5 (d, CH3, 'J(CP) 3.2 Hz), 29.0 (d, CH2, WCP) 7.2 Hz), 34.1 (d, t-C, 'J(CP) 12.2 Hz), 97.2 (s, ring C); 31P NMR (CsDs) 6 24.0 (s). MS(C1) 457 [M C1-I. HRMS calcd 422.019124, found 422.018795. Anal. Calcd for C15H&lzIfl: C, 42.97; H, 6.19. Found: C, 43.64; H, 6.60.
+
Synthesis of Dimethyl[(1-q1-(2-di-tert-butylphosphino)ethylcyclopentadienyllgallium (5). Method A. A solution of 0.24 g (1.0 mmol) of 1 in 20 mL of THF was added at -78 "C t o a stirred solution of MezGaCl(O.13 g, 1.0 mmol) in 30 mL of THF. M e r 3 h at -78 "C, the stirred solution was allowed to warm to room temperature. The solvent and volatiles were removed under reduced pressure, and the resulting residue was extracted with hexane (60 mL), filtered, and concentrated. Colorless crystals of 5 (mp 98-99 "C) formed upon cooling this solution to -20 "C for 12 h. IH NMR (CsD6): 6 -0.35 (d, GaCH3, 6 H), 0.94 (d, CH3, 18 H), 1.62 (m, CHz, 2 H), 2.81 (m, CH2, 2 HI, 5.25 (s, ring H, 2 H), 6.55 ( 8 , ring H, 2 H); I3C{lH} NMR ((&De): 6 -5.5 (d, GaCH3, V(CP) 16.7 Hz), 20.1 (d, CHz, 'J(CP1 14.6 Hz), 29.2 (d, CH3, V(CP) 4.7 Hz), 26.3 (d, CH2, 'J(CP) 7.2 Hz), 32.7 (d, t-C, 'J(CP) 7.4 Hz), 92.4 (s, ring C), 123.7 ( 8 , ring C); 31PNMR (CSD6): 6 5.5 (9). MS(C1) 339 [M+I. HRMS calcd 336.149 746. ~found ----336.149 160. Anal. C&d for C17H32GaP: C, 60.55; H, 9.59. Found: C, 55.52; H, 9.21. I
(8) Wilcox, C.F.;Craig, R. R.J.Am. Chem. SOC.1981,83, 3866. (9) Hoffman, H.; Schellenbeck, P. Chem. Ber. 1968,99,1134.
(Cyclopentadienylalky1)phosphineDerivatives of Ga(II) and In(III) Table 4. Atomic Coordinates (104) and Equivalent Isotropic Displacement Coefficients (A2103) for 3 and 4 atom
xla
vlb
8235(1) 682 l(3) 10256(3) 6628(4) 9230(11) 8659(14) 7550(15) 7347(13) 8353(14) 8590(14) 7 197(13) 7644(11) 9344( 11) 7566(11) 6908(12) 472%10) 3850(12) 4317(11) 4245(10)
Compound 4 9080(1) 10379(1) 9704(2) 4 0 3 ~ 8139(6) 7188(7) 6993(7) 774(7) 846l(6) 9425(6) 10047(7) 11586(6) 11516(7) 11861(6) 12357(6) 10275(7) 10847(9) 9225(7) 10616(7)
2 134(1) 1231(1) 3012(2) 3220(2) 1122(6) 1301(7) 741(8) 160(7) 351(5) -71(6) 72(3 1407(7) 1163(7) 2389(6) 849(7) 1357(7) 669(8) 1266(7) 2283(6)
2290(1) 2538( 1) 3710(4) 3817(5) 4550(6) 976(5) 4512(4) 4763(5) 3969(4) 303(5) 1237f5) 2305(5) 320 l(5) 1825(5) 2252(7) 1990(6) 632(5) 2335(5) 1043(5)
Compound 5 1284(1) -471(2) 2310(5) 3283(6) 2842(8) 1593(7) 1277(6) 32(7) -340(6) -2299(6) -2364(7) -3360(6) -2663(6) -44(7) -828(8) 1497(7) -313(8) 418(6) 2483(7)
874(1) 2086(1) 1465(4) 778(4) 30(4) 714(5) 1428(4) 2012(5) 603(4) 1710(4) 105l(4) 2455(4) 1213(5) 3011(4) 3884(4) 3207(5) 2722(5) -278(3) 884(4)
IIC
Ueal
Organometallics, Vol. 14,No.1, 1995 23
of 0.24 g (1.0 "01) of 1 in 20 mL of THF was added at -78 "C to a stirred solution of MezInCl (0.18 g, 1.0 mmol) in 30 mL of THF. After 3 h at -78 "C, the stirred solution was allowed to warm to room temperature. The solvent and volatiles were removed under reduced pressure, and the resulting residue was extracted with hexane (100 mL), filtered, and concentrated to 20 mL. Cooling the solution overnight at -20 "C resulted in a white, powdery 6 (mp 97-99 " 0 . 'H " I R (CsDe): 6 -0.11 (d, InCH3, 6 H), 0.81 (d, CH3, 18 H), 1.56 (m, CHz, 2 H), 2.82 (m, CHz, 2 H), 5.74 (s, ring H, 2 H), 6.79 (s, ring H, 2 H); l3C(lH} NMR (CsDs): 6 1.4 (d, InCH3, 'J(CP) 15.8 Hz), 21.5 (d, CHz, 'J(CP) 15.2 Hz), 27.0 (d, CHz, V(CP) 7.8 Hz), 29.2 (d, CH3, 'J(CP) 4.6 Hz), 33.1 (d, t-C, 'J(CP) 14.2 Hz), 96.1 (8, ring C), 118.4 (s, ring c). 31P NMR (CsDs): 6 10.5 (9). MS (CI) 383 [M+]. HRMS calcd 383.135 865, found 383.134 827. Anal. Calcd for C17H32InP: C, 53.42; H, 8.44. Found: C, 52.68; H, 7.92. Method B. A solution of 0.34 g (1.4 mmol) of 2 in 20 mL of toluene was added to a stirred solution of Me3In (0.23 g, 1.4 mmol) in 20 mL of toluene. The stirred solution was refluxed for 24 h. The solvent and volatiles were removed under reduced pressure to yield white powdery 6. The product was identified by 31PNMR spectroscopy. X-ray Crystallography. Details of the crystal data and a summary of intensity data collection parameters for 4 and 5 are presented in Table 3. Atomic coordinates and equivalent isotropic thermal parameters for 4 and 5 are listed in Table 4. The crystals were mounted in thin-walled glass capillaries and sealed under argon. Both data sets were collected at 25 "C on an Enraf-Nonius CAD-4 diffractometer. The unit cell parameters were obtained by centering 25 reflections having 28 values between 16 and 24". For both structures, the data were corrected for Lorentz and polarization effects. The structures were solved by direct methods and successive cycles of difference maps followed by least-squares refinements. All calculations were performed using the Siemens SHEIXTL PLUS (PC version) programs.
Acknowledgment. We thank the Robert A. Welch Foundation, the National Science Foundation, and the Science and Technology Center Program of the National Science Foundation (Grant CHE-8920120) for their generous support of this research.
Method B. A solution of 0.34 g (1.4 mmol) of 2 in 20 mL of toluene was added to a stirred solution of Me3Ga (0.23 g, 1.4 mmol) in 20 mL of toluene. The stirred solution was refluxed Supplementary Material Available: Tables of atomic for 24 h. The solvent and volatiles were removed under parameters, thermal parameters, bond distances and angles, reduced pressure to yield 5 as a white powder. The product and hydrogen atom coordinates for 4 and 5 (6 pages). Ordering was identified by 31PNMR spectroscopy. information is given on any current masthead page. Synthesisof Dimethyl[l-~1-(2-di-tert-butylphosphJno)OM9403535 ethylcyclopentadienyllindium (6). Method A. A solution
