Supporting Information

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1 Supporting Information Wiley-VCH Weinheim, Germany

2 Reductive Elimination of Ether from T-Shaped, Monomeric Arylpalladium Alkoxides James P. Stambuli, Zhiqiang Weng, Christopher D. Incarvito and John F. Hartwig* Department of Chemistry, University of Illinois Urbana-Champaign, 600 South Mathews Ave, Urbana, IL and Department of Chemistry, Yale University, P.O. Box , New Haven, CT General Methods. 1 H and 13 C NMR spectra were recorded on a Bruker DPX 400 MHz Spectrometer, Bruker DPX 500 MHz Spectrometer, or a General Electric Omega 300 or 500 spectrometer with tetramethylsilane or residual protiated solvent used as a reference. Elemental analyses were performed by Robertson Microlabs, Inc., Madison, NJ. All 31 P and 13 C NMR spectra were proton decoupled. Toluene, tetrahydrofuran, ether and pentane were distilled from sodium/benzophenone. Silver triflate and sodium tert-butoxide were purchase from Aldrich and used as received. The syntheses of 1-AdP t Bu 2 Pd(Ph)Br and P t Bu 3 Pd(Ph)Br, [1] and NaOC(CF 3 ) 3 and NaOC(CF 3 )(CH 3 ) 2, [2] have been reported previously. P t Bu 3 Pd(o-tol)Br. In a glovebox, 81 mg (0.16 mmol) of Pd[PtBu 3 ] 2, 1 ml of 2- bromotoluene and a stir bar were added to a screw-capped vial. The vial was removed from the glovebox and heated at 70 C for 3 h. After this time, the vial was returned to the drybox, and the solution was poured into a flask filled with 15 ml of pentane. An orange precipitate was immediately formed. The flask was stirred for 5 min. At this time, the orange precipitate was washed 5 4 ml with pentane. The orange solid was dried under vacuum to yield 42 mg (55 % yield) of the desired product. 1 H NMR(CD 2 Cl 2, 500 MHz) δ 1.49 (d, J = 12.5 Hz, 27H), 2.89 (s, 3H), 6.76 (m, 1H), 6.85 (m, 2H), 7.21 (dd, J = 8, 3.5 Hz, 1H); 13 C NMR(CD 2 Cl 2, 125 MHz) δ

3 28.6, 32.0 (d, J = 2.8 Hz), 40.7 (d, J = 9.7 Hz), 124.5, (d, J = 2.9 Hz), 129.4, (d, J = 5.9 Hz), 135.0, 140.2; 31 P NMR(CD 2 Cl 2, 202 MHz) δ Anal. Calc'd. for C 19 H 34 BrPPd: C, 47.56; H, Found: C, 47.42; H, (1-AdP t Bu 2 )Pd(o-tol)Br. In a glovebox, 105 mg (0.158 mmol) of Pd[(1-AdP t Bu 2 )] 2, 1.2 ml of 2-bromotoluene and a stir bar were added to a screw-capped vial. The vial was removed from the glovebox and heated at 70 C for 3 h. After this time, the vial was returned to the drybox and poured into a flask filled with 20 ml of pentane. The flask was cooled at -35 C for 24 h. The flask was removed from freezer, and the red-orange precipitate that formed was washed 5 4 ml with pentane. The orange solid was dried under vacuum to yield 51 mg (58 % yield) of the desired product. 1 H NMR(C 6 D 6, 400 MHz) δ 1.00 (d 7.2 Hz, 9H), 1.04 (d, J=6.8 Hz), 1.39 (br m, 6H), 1.61 (br s, 3H), 1.88 (br m, 3H), 2.02 (br m, 3H), 3.11 (s, 3H), 6.70 (t, J = 7.2 Hz, 1H), 6.78 (m, 2H), 7.33 (d, J = 8 Hz, 1H); 13 C NMR(C 6 D 6, 125 MHz) δ 28.8 (d, J = 7.8 Hz), 29.22, 32.0, 32.1, 36.2, (d, J= 7.8 Hz), (d, J=7.8). 41.3, 47.3 (d, J = 7.8 Hz), 124.3, 128.2, 129.2, (d, J = 5.9 Hz), 135.8, 140.4; 31 P NMR(C 6 D 6, 162 MHz) δ Anal. calcd. for C 25 H 40 BrPPd: C, 53.82; H, Found: C, 53.49; H, [(1-AdP t Bu 2 )Pd(OC 6 H 2 (2,4,6-C 4 H 9 ))(Ph)] (2). In a glovebox, 50 mg (0.092 mmol) of 1- AdP t Bu 2 Pd(Ph)Br was dissolved in 2 ml of THF and stirred. In a separate vial, sodium 2,4,6-tritert-phenoxide OEt 2 (39 mg, 0.11 mmol) was dissolved in 1 ml of THF. The phenoxide solution was added dropwise to the stirred vial. The solution changed from clear orange to cloudy, bright orange. The reaction was stirred for an additional 2 min. After this time, the reaction mixture was filtered through a plug of Celite, and the THF was evaporated under reduced pressure. The resulting orange residue was dissolved in 5 ml of pentane, filtered through Celite and concentrated to half of the volume. The orange pentane solution was cooled

4 at -35 C. After 6 h, bright orange crystals were formed. The solvent was removed from the crystals by pipette, and the crystals were dried under vacuum to yield 64% (42 mg, mmol) of the desired product. 1 H NMR (CD 2 Cl 2, 400 MHz) δ 1.22 (s, 9H), 1.35 (d, J = 12.4 Hz, 18H), 1.53 (br s, 6H), 1.71 (br s, 3H), 1.77 (s, 18H), 1.86 (br s, 6H), (br m, 3H), 7.05 (s, 2H), (br m, 2H); 13 C{ 1 H} NMR (CD 2 Cl 2, 100 MHz) δ 29.2 (d, J = 6.7 Hz), 31.9, 32.2 (d, J = 2.7 Hz), 32.2, 34.5, 36.3, 36.5, 39.2 (d, J = 10.2 Hz), 41.8, 46.9 (d, J = 11.0 Hz),122.2, 123.9, 127.0, (d, J = 2.1 Hz), 140.6, 140.7, (d, J = 2.5 Hz), 163.4; 31 P NMR (CD 2 Cl 2, 202 MHz) δ Anal. calcd. for C 42 H 67 OPPd: C, 69.54; H, Found: C, 69.22; H, [(P t Bu 3 )Pd(Ph)(p-OCH 3 C 6 H 4 )] 2 (3). In a glovebox, 25 mg (0.17 mmol) of sodium p- methoxyphenoxide was suspended in 1 ml of THF and stirred. In a separate vial, P t Bu 3 Pd(Ph)Br (40 mg, mmol) was dissolved in 1 ml of toluene and added dropwise to the stirred suspension of the phenoxide. The reaction was stirred for 30 min. After this time, THF was evaporated from the reaction mixture under reduced pressure. The resulting yellow residue was dissolved in 8-10 ml of toluene, filtered through a Celite plug, and concentrated to approximately 1 ml. The toluene solution was layered with pentane and cooled at -35 C. After 16 h, thin, yellow needles were collected, washed with pentane, and dried under vacuum to yield 50% (44 mg, mmol) of 3. 1 H NMR (C 6 D 6, 400 MHz) δ 1.31 (d, J = 12.0 Hz, 54H), 3.39 (s, 6H), 6.54 (br s, 4H), 6.69 (d, J = 7.6 Hz, 4H), 6.94 (m, 6H), 7.52 (br s, 4H); 13 C NMR{ 1 H} (C 6 D 6, 100 MHz) δ 33.2 (d, J = 3.9 Hz), 40.6 (d, J = 9.2 Hz), 55.1, (br s), 123.5, (br s), 126.6, 138.3, (d, J = 6.5 Hz), 152.2, 158.6; 31 P NMR (C 6 D 6, 202 MHz) δ Anal. calcd. for C 50 H 78 O 4 P 2 Pd 2 : C, 59.00; H, Found: C, 58.74; H, Generation and characterization of [(P t Bu 3 )Pd(o-tol)(O t C 4 H 9 )] (4b) at low temperature. A 600 µl CD 2 Cl 2 solution of P t Bu 3 Pd(o-tol)(Br) (10.0 mg, mmol) was

5 placed into a screw-capped NMR tube and cooled to -75 C. To this tube was added by syringe 200 µl of a solution of NaO t Bu (0.12 M, mmol) in CD 2 Cl 2. The reaction was agitated and immediately turned from yellow to red orange. The tube was placed into an NMR spectrometer probe that was pre-cooled to 10 C. The reaction was monitored by 31 P NMR spectroscopy until P t Bu 3 Pd(o-tol)(Br) was completely consumed. 1 H NMR (CD 2 Cl 2, 500 MHz, -10 C) δ 1.03 (s, 9H), 1.44 (d, J = 12.0 Hz, 27H), 2.88 (s, 3H), (m, 1H), (m, 2H), 7.34 (d, J = 8 Hz, 1H); 13 C NMR{ 1 H} (CD 2 Cl 2, 151 MHz, -10 C) δ 27.4 (d, J = 5.7 Hz), 31.9, 35.0, 39.1 (d, J = 10.3 Hz), 71.6, 123.3, 123.5, 128.0, 136.3, (d, J = 4.5 Hz), 142.0; 31 P NMR (CD 2 Cl 2, 202 MHz, -10 C) δ {(1-AdP t Bu 2 )Pd(Ph)[OC(CF 3 ) 3 ]} (5). In a glovebox, 30 mg (0.055 mmol) of 1- AdP t Bu 2 Pd(Ph)Br and 16 mg of NaOC(CF 3 ) 3 were dissolved in 2 ml of toluene, and the solution was stirred. In a separate vial, silver triflate (15 mg, mmol) was dissolved in 1 ml of toluene. The triflate solution was added dropwise to the stirred solution of palladium and alkoxide. A precipitate formed immediately. The reaction was stirred for an additional 5 min. After this time, the reaction mixture was filtered through Celite, and all of the toluene was evaporated under reduced pressure. The resulting yellow-orange residue was dissolved in a minimum amount of ether (ca. 10 ml), and cooled at 35 C. After 12 h, yellow crystals were collected, washed quickly with pentane, and dried under vacuum to yield 28% (11 mg, mmol) of 5. 1 H NMR (C 6 D 6, 400 MHz) δ 1.02 (d, J = 12.4 Hz, 18H), (br m, 6H), 1.68 (br s, 3H), 1.89 (br s, 6H), (m, 3H), (m, 2H); 13 C{ 1 H} NMR (C 6 D 6, 100 MHz) δ 29.2 (d, J = 7.5 Hz), 32.3 (d, J = 2.4 Hz), 36.5 (d, J = 1.2 Hz), 39.9 (d, J = 12.1 Hz), 41.7, 47.8 (d, J = 11.4 Hz), 125.2, 127.4, (d, J = 3.1 Hz), 128.4, (d, J = 3.0 Hz), C(CF 3 ) 3

6 and C(CF 3 ) 3 were not observed; 31 P NMR (C 6 D 6, 212 MHz) δ 65.0; 19 F NMR (C 6 D 6, 376 MHz) δ Anal. calcd. for C 28 H 38 F 9 OPPd: C, 48.11; H, 5.48; Found: C, 47.85; H, {(1-AdP t Bu 2 )Pd(Ph)[OC(CH 3 ) 2 (CF 3 )]} (6a). Prepared from 60 mg (0.11 mmol) of 1a according to the procedure for the synthesis of mg (52% yield). 1 H NMR (C 6 D 6, 400 MHz) δ 1.10 (d, J = 11.6 Hz, 18H), (m, 12H), 1.71 (br s, 3H), 2.01 (s, 6H), (m, 3H), 7.60 (d, J = 7.6 Hz, 2H); 13 C{ 1 H} NMR (C 6 D 6, 100 MHz) δ 28.3, 28.9 (d, J = 7.5 Hz), 32.0, 36.3, 39.2 (d, J = 9.9 Hz), 41.4, 46.2 (d, J = 9.8 Hz), 124.0, 126.9, (d, J = 3.3 Hz), (d, J = 2.3 Hz), C(CF 3 )(CH 3 ) 2 and C(CF 3 ) 3 were not observed; 31 P NMR (C 6 D 6, 212 MHz) δ 63.0; 19 F NMR (C 6 D 6, 376 MHz) δ Anal. calcd. for C 28 H 44 F 3 OPPd: C, 56.90; H, Found: C, 56.86; H, [(P t Bu 3 )Pd(o-tol)(p-OCH 3 C 6 H 4 )] 2. Prepared from 61 mg (0.13 mmol) of [(P t Bu 3 )Pd(otol)(Br)] according to the procedure for the synthesis of mg (0.025 mmol). 1 H NMR (C 6 D 6, 400 MHz) δ 1.29 (d, J = 12.4 Hz, 54H), 2.63 (s, 6H), 3.38 (s, 6H), (br m, 14H), 7.66 (br s, 2H); 31 P NMR (C 6 D 6, 202 MHz) δ Representative Procedure for Measuring the Yield of Aryl Ether from Reductive Elimination. [(P t Bu 3 )Pd(Ph)(p-OCH 3 C 6 H 4 )] 2 (3) (5.0 mg, mmol) was weighed into a vial and dissolved in 712 µl of C 6 D 6. Next, 47.6 µl of a 0.21 M stock solution of P t Bu 3 in C 6 D 6 (0.010 mmol), and 40.0 µl of a 0.25 M stock solution of 1,3,5-trimethoxybenzene (0.010 mmol) were added to the vial. The contents of the vial were agitated and then transferred to an NMR tube containing a septum-lined screw-cap. The tube was heated at 70 C, and the reaction progress was monitored by 1 H NMR spectroscopy until the yield of aryl ether, determined by integration against the trimethoxybenzene internal standard, remained constant.

7 Kinetic analysis of reductive elimination reaction from 4a in CD 2 Cl 2. Three 400 µl CD 2 Cl 2 solution of the [(P t Bu 3 )Pd(Ph)(Br)] (9.0 mg, mmol) were transferred to three screw-capped NMR tubes containing a glass capillary filled with P(O)(OPh) 3 in toluene-d 8 as an integration standard. The NMR tubes were cooled to -75 C. To these tubes were added by syringe 81 µl (0.24 M, mmol) of a CD 2 Cl 2 solutions of P t Bu 3, or 19.0 mg (0.095 mmol), and 39.0 mg (0.19 mmol) of P t Bu 3 in CD 2 Cl 2, respectively, and 168 µl (0.12 M, 0.02 mmol) of CD 2 Cl 2 solutions of NaO t Bu. CD 2 Cl 2 solutions of trimethoxy benzene were added as an integration standard for determination of ether yield. The NMR solutions were diluted to 0.8 ml to produce three solutions that contained a 24 mm concentration of [(P t Bu 3 )Pd(Ph)(Br)], 25 mm concentration of NaO t Bu and 24 mm, 119 mm and 238 mm concentration of P t Bu. After shaking the mixtures, each NMR tube was quickly placed into a pre-cooled NMR spectrometer probe at -10 C. A 31 P{ 1 H} NMR spectrum were obtained at -10 C to ensure complete generation of the palladium alkoxide prior to acquiring kinetic data. Several minutes after the temperature of NMR probe was elevated to 30 C, kinetic measurements were started. The decay of the palladium alkoxide complex 4a was monitored at 30 C by the intensity of the 31 P{ 1 H} NMR resonance of the coordinated P t Bu 3 vs the P(O)(OPh) 3 standard contained in the glass capillary. 31 P{ 1 H} NMR spectra were obtained every 10 seconds at 30 C. The following firstorder rate constants were obtained: 2.6± s -1 (24 mm of P t Bu 3 ), 2.4± s -1 (119 mm of P t Bu 3 ), 2.5± s -1 (238 mm of P t Bu 3 ). The yields of ether from reductive elimination (59-62 %) were determined by integrating the resonances of the Ph group versus the trimethoxybenzene internal standard. Kinetic analysis of reductive elimination reaction from 4b in toluene-d 8. Three 400 µl portions of a toluene-d 8 solution of [(P t Bu 3 )Pd(o-tol)(Br)] (5.0 mg, mmol) were placed

8 into three screw-capped NMR tubes. Toluene-d 8 solutions of trimethoxybenzene (50 µl of a 0.24 M solution) were added as an integration standard. The NMR tubes were cooled to -75 C. To these tubes were added by syringe 2.0 mg (0.010 mmol), 10.1 mg ( mmol), and 20.1 mg (0.100 mmol) of P t Bu 3 in 0.10 ml of toluene-d 8 respectively, following by addition of 125 µl of a 0.12 M solution of NaO t Bu (0.15 mmol) toluene-d 8. The NMR solutions were diluted to 0.80 ml to produce three samples that contained a 12 mm concentration of [(P t Bu 3 )Pd(o-tol)(Br)], 19 mm concentration of NaO t Bu and 12 mm 62 mm and 120 mm concentrations of P t Bu. After shaking the mixtures, each NMR tube was quickly placed into the pre-cooled NMR spectrometer probe at -10 C. A 1 H NMR spectrum was obtained at -10 C to ensure complete generation of the palladium alkoxide prior to acquiring kinetic data. Several minutes after the temperature of the NMR probe was elevated to 15 C, kinetic measurements were started. The decay of the palladium alkoxide complex 4b was monitored at 15 C by the intensity of an 1 H NMR resonance of the o-tol group versus the trimethoxybenzene standard. Pulse delays of 2.0 s were used to ensure accurate integration. 1 H NMR spectra were obtained every 90 seconds at 15 C. The following first-order rate constant was obtained: 4.1± s -1 (12 mm of P t Bu 3 ), 4.4± s -1 (62 mm of P t Bu 3 ), 5.3± s -1 (120 mm of P t Bu 3 ). The yields of ether from reductive elimination were determined with the integration of o-tol group vs trimethoxy benzene standard and were all greater than 99 %. Kinetic analysis of reductive elimination reaction from 6b in C 6 D 6. Three 400 µl portions of C 6 D 6 solutions of {(1-AdP t Bu 2 )Pd(o-tol)[OC(CH 3 ) 2 (CF 3 )]} (6b) (6.1 mg, mmol) were placed into three screw-capped NMR tubes. The C 6 D 6 solutions of trimethoxy benzene were added as an integration standard. To these tubes were added by syringe 2.8 mg (0.010 mmol), 14.0 mg ( mmol), and 28.0 mg (0.100 mmol) of 1-AdP t Bu 2 in C 6 D 6 solution

9 respectively. The NMR solutions were diluted to 0.8 ml to produce three solutions that contain a 12 mm concentration of 6b and 12 mm, 62 mm and 120 mm concentrations of 1-AdP t Bu 2. After shaking the mixtures, each NMR tube was quickly placed into a pre-heated NMR spectrometer probe at 73 C, and kinetic measurements were started. The decay of the palladium alkoxide complex 6b was monitored at 73 C by the intensity of the 1 H NMR resonance of the o-tol group vs the trimethoxy benzene standard. Pulse delays of 2.0 s were used to ensure accurate integration. 1 H NMR spectra were obtained every 90 seconds at 73 C. The following first-order rate constant was obtained: 4.6± s -1 (12 mm of P t Bu 3 ), 4.2± s -1 (62 mm of P t Bu 3 ), 5.8± s -1 (125 mm of P t Bu 3 ). The yields of ether from reductive elimination (62-65 %) were determined with the integration of a resonance of an o-tol group versus trimethoxy benzene standard. References 1) J. P. Stambuli, M. Buhl, J. F. Hartwig, J. Am. Chem. Soc. 2002, 124, ) J. A. Samuels, K. Folting, J. C. Huffman, K. G. Caulton, Chem. Mater. 1995, 7,

10 Structure solutions of compound 2. Data Collection An orange plate crystal of C 42 H 67 OPPd having approximate dimensions of 0.20 x 0.20 x 0.15 mm was mounted with epoxy cement on the tip of a fine glass fiber. All measurements were made on a Nonius KappaCCD diffractometer with graphite monochromated Mo-Kα radiation. Cell constants and an orientation matrix for data collection corresponded to a C-centered monoclinic cell with dimensions: a = (7) Å α = 90 o b = (19) Å β = 92.06(3) o c = (5) Å γ = 90 o V = 7787(3) Å 3 For Z = 8 and F.W. = , the calculated density is g/cm 3. Based on a statistical analysis of intensity distribution, and the successful solution and refinement of the structure, the space group was determined to be: C2/c (#15) The data were collected at a temperature of 183(2) K to a maximum 2θ value of o. Two omega scans consisting of 85, and 60 data frames, respectively, were collected with a frame width of 1.4 and a detector-to-crystal distance, Dx, of 35 mm. Each frame was exposed twice (for the purpose of de-zingering) for a total of 126 seconds. The data frames were processed and scaled using the DENZO software package. 1 Data Reduction A total of reflections were collected of which 8881 were unique and observed (R int = ). The linear absorption coefficient, µ, for Mo-Kα radiation is 5.47 cm -1 and no absorption correction was applied. The data were corrected for Lorentz and polarization effects. Structure Solution and Refinement The structure was solved by direct methods and expanded using Fourier techniques 2. The non-hydrogen atoms were refined anisotropically and hydrogen atoms were treated as idealized contributions. The final cycle of full-matrix least-squares refinement 3 on F was based on 8881 observed reflections (I > 2.00σ(I)) and 406 variable parameters and converged with unweighted and weighted agreement factors of: R = Σ Fo - Fc / Σ Fo = Rw = [ Σ w ( Fo - Fc ) 2 / Σ w Fo 2 ] 1/2 =

11 The maximum and minimum peaks on the final difference Fourier map corresponded to and e - /Å 3, respectively. Structural Description The compound crystallized in the C-centered monoclinic space group C2/c with one molecule in the asymmetric unit and eight in the unit cell. The geometry about the palladium atom is square planar with the fourth coordination site occupied by a hydrogen atom of the adamantyl group [H(2B)]. The Pd(1)-H(2B) distance is 2.14 Å, and angles associated with this interaction are 79.4 [H(2B)-Pd(1)-P(1)], 93.8 [H(2B)-Pd(1)-O(1)], and [H(2B)-Pd(1)- C(19)]. The coordination plane of palladium, including H(2B), is planar (mean deviation = 0.51 Å) and phenyl rings 1 [C(19-24)] and 2 [C(25-30)] are offset from this plane by 91.3 and 94.7 respectively. There are no significant intermolecular contacts. Structure solution of compound 6a. Data Collection A yellow block crystal of C 28 H 44 F 3 OPPd having approximate dimensions of 0.30 x 0.25 x 0.25 mm 3 was mounted with epoxy cement on the tip of a fine glass fiber. All measurements were made on a Nonius KappaCCD diffractometer with graphite monochromated Mo-Kα radiation. Cell constants and an orientation matrix for data collection corresponded to a primitive monoclinic cell with dimensions: a = (3) Å α = 90 o b = (2) Å β = (3) o c = (4) Å γ = 90 o V = (9) Å 3 For Z = 4 and F.W. = , the calculated density is g/cm 3. Based on a statistical analysis of intensity distribution, and the successful solution and refinement of the structure, the space group was determined to be: P2 1 /c (#14)

12 The data were collected at a temperature of 113(2) K to a maximum 2θ value of o. Five omega scans consisting of 42, 33, 42, 28, and 13 data frames, respectively, were collected with a frame width of 1.8 and a detector-to-crystal distance, Dx, of 35.0 mm. Each frame was exposed twice (for the purpose of de-zingering) for a total of 36 seconds. The data frames were processed and scaled using the DENZO software package. 1 Data Reduction A total of reflections were collected of which 6687 were unique and observed (R int = ). The linear absorption coefficient, µ, for Mo-Kα radiation is 7.84 cm -1 and no absorption correction was applied. The data were corrected for Lorentz and polarization effects. Structure Solution and Refinement The structure was solved by direct methods and expanded using Fourier techniques 2. The non-hydrogen atoms were refined anisotropically and hydrogen atoms, with exceptions noted, were treated as idealized contributions. The final cycle of full-matrix least-squares refinement 3 on F was based on 6687 observed reflections [I > 2.00σ(I)] and 315 variable parameters and converged with unweighted and weighted agreement factors of: R = Σ Fo - Fc / Σ Fo = Rw = {Σ[w (F o 2 F c 2 ) 2 ] / Σ[w(F o 2 ) 2 ]} 1/2 = The maximum and minimum peaks on the final difference Fourier map corresponded to and e - /Å 3, respectively. Structural Description The compound crystallized in the monoclinic space group P2 1 /c with one molecule in the asymmetric unit and four molecules in the unit cell. The geometry about Pd(1) is square planar with the final coordination site occupied by H(1), of the adamantyl group with a Pd H distance of 2.18(3) Å. The palladium coordination plane possesses a mean deviation of Å with trans angles of (5) for P(1)-Pd(1)-O(1) and 175.5(7) for C(19)-Pd(1)-H(1). The phenyl ring, C(19-24), is offset from the palladium coordination plane by Deviation from the

13 expected orthogonal relationship results from the steric bulk imparted on the phenyl ring by the t Bu-groups of the phosphine ligand. Hydrogen H(1) and its C(4) counterpart H(2) were located from the electron difference map and refined with isotropic displacement parameters. C H distances are 0.97(3) and 0.98(3) Å for H(1) and H(2) respectively. There are no significant intermolecular contacts Structure solutions of compound 6b Information on the structure solution of compound 6b is contained in the.cif file. References to Structure Solutions (1) Z. Otwinowski and W. Minor, "Processing of X-Ray Diffraction Data Collected in Oscillation Mode," Methods in Enzymology, vol. 276: Macromolecular Crystallography, part A, , 1997, C.W. Carter, Jr. & R.M. Sweet, Eds., Academic Press. (2) Acta Cryst. A46 (1990) (3) Least Squares function minimized: Σw( Fo - Fc ) 2