Supporting Information

Supporting Information Wiley-VCH 2006 69451 Weinheim, Germany

A New Melt Approach to the Synthesis of catena- Phosphorus Dications to Access the First Derivatives of 2+ ** [P 6 Ph 4 R 4 ] Jan J. Weigand*, Neil Burford*, Michael D. Lumsden, Andreas Decken This PDF file includes: 1. Experimental 2. NMR Spectroscopical Details Figure S1-S5 3. Crystallographic Details Table S1-S3 4. Newman Projection Figure S6 and S7 5. References 1

1. Experimental General Remarks. Solvents were dried on an MBraun solvent purification system and stored under nitrogen and over molecular sieves prior to use. (PPh) 5 was prepared according to literature methods (1). Gallium trichloride, diphenychlorophosphine and dimethylchlorophosphine were used as received from Aldrich and Strem, respectively. NMR: Bruker AVANCE 500 ( 1 H (500.13 MHz), 13 C (125.76 MHz) chemical shift referenced to δ TMS = 0.00; 31 P (202.46 MHz) to δ H3PO4(85%) = 0.00). Due to the complexity of the 31 P NMR spectra, all reported 31 P NMR parameters were derived by matching the observed experimental spectra with a computer simulation using the software program gnmr, version 4.0, by Cherwell Scientific. In each case, the uniqueness of the solution was verified by using the simulated parameters to simulate the experimental 31 P spectra obtained at a second applied field strength (Bruker AC-250 ( 31 P 101.23 MHz)). Melting points were recorded on an Electrochemical melting point apparatus in a sealed capillaries under dinitrogen and are uncorrected. Infrared spectra were recorded on a Nicolet 510P spectrometer as film or powdered sample between CsJ pellets. Raman spectra were obtained for powdered and crystalline samples on a Bruker RFS 100 instrument equipped with a Nd:YAG laser (1064 nm). Chemical analyses were determined by Canadian Microanalytical Service LTD., Delta, BC, Canada. [Ph 8 P 6 ][GaCl 4 ] 2, (±)[6a][GaCl 4 ] 2 : A mixture of (PhP) 5 (1297 mg, 2.4 mmol), Ph 2 PCl (1077 µl, 6.0 mmol) and GaCl 3 (1057 mg, 6.0 mmol) was stirred and heated under argon to 165 C within 30 min. A yellow melt was obtained between 70 and approx. 125 C and subsequently solidified up to 165 C yielding (±)[6a][GaCl 4 ] 2 as colorless solid. Solutions of (±)[6a][GaCl 4 ] 2 show evidence of decomposition already within ~1 hour at RT; M.p. 195-205 C (dec.); 1 H NMR (d 3 -MeCN, 273 K): δ = 7.02-7.85 (m, Ph) ppm; 13 C NMR (d 3 -MeCN, 273 K): δ = 113.3-135.9 (several s and m, Ph) ppm; 31 P NMR (101.3 MHz, d 3 -MeCN, 273 K): AA A A BB spin system, δ A = δ A = δ A = δ A = - 60.8 ppm, δ B = δ B = +29.8 ppm, 1 J AB = 1 J A B = 1 J A B = 1 J A B = 1 J A B = -310.5 Hz, 1 J AA = 1 J A A = -80.9 Hz, 2 J A B = 2 J A B = 2 J AB = 2 J A B = +89.4 Hz, 2 J AA = 2 J A A = -12.2 2

Hz, 3 J AA = 3 J A A = +98.5 Hz, 4 J BB = +5.1 Hz; Raman (250 mw, 25 C, cm -1 ): 3138 (6), 3055 (74), 1580 (69), 1193 (8), 1161 (10), 1088 (24), 1026 (53), 1001 (81), 693 (10), 617 (15), 492 (13), 438 (14), 343 (31), 324 (28), 272 (17), 201 (27), 159 (8), 104 (81), 86 (100); FT-IR (film, CsI): ν = 3054 (m), 3034 (vw), 2668 (vw), 2573 (vw), 1967 (vw), 1890 (vw), 1810 (vw), 1669 (vw), 1581 (m), 1570 (m), 1479 (m), 1435 (vs), 1387 (w), 1336 (m), 1311 (m), 1265 (m), 1189 (m), 1164 (w), 1095 (vs), 1091 (s), 1089 (s), 1075 (s), 1023 (m), 997 (s), 974 (w), 922 (w), 839 (w), 799 (w), 739 (vs), 684 (vs), 614 (vw), 524 (m), 487 (s), 476 (s), 457 (m), 443 (m), 402 (s), 374 (vs), 344 (m), 328 (m), 296 (m); elemental analysis for C 48 H 40 Cl 8 Ga 2 P 6 (1225.74): calcd. C 47.03, H 3.29; found: C 45.70, H 3.08. 3

[Me 4 Ph 4 P 6 ][GaCl 4 ] 2, [6b][GaCl 4 ] 2 : A solution of (PhP) 5 (432 mg, 0.8 mmol), Me 2 PCl (158 µl, 2.0 mmol) and GaCl 3 (352 mg, 2.0 mmol) in dichloromethane (7 ml) was stirred for 3 days under nitrogen. During this time [6b][GaCl 4 ] 2 precipitated from the reaction mixture and was separated by filtration yielding 440 mg (45 %) of a white amorphous powder; M.p. 163-167 C; 1 H NMR (d 3 -MeCN, 273 K, [(±)[6c][GaCl 4 ] 2 ]): δ = 1.85 [1.88] and 2.26 (s, 1 H{ 31 P}), 7.53-7.92 [7.64-7.81] (m, Ph) ppm; 13 C NMR (d 3 - MeCN, 273 K, [(±)[6c][GaCl 4 ] 2 ]): δ = 8.6 [5.8] (d, 1 J PC = ca. 32.0 [13.4] Hz), 116.8-136.3 (several s and m, Ph) ppm; 31 P NMR (101.3 MHz, d 3 -MeCN, 273 K, [6a]): AA A A BB spin system, δ A = δ A = δ A = δ A = -63.6 [-53.5] ppm, δ B = δ B = +12.4 [+11.2] ppm, 1 J AB = 1 J A B = 1 J A B = 1 J A B = 1 J A B = -306.2 [-295.2] Hz, 1 J AA = 1 J A A = -85.8 [-4.0] Hz, 2 J A B = 2 J A B = 2 J AB = 2 J A B = +79.1 [+54.9] Hz, 2 J AA = 2 J A A = - 11.1 [-71.4] Hz, 3 J AA = 3 J A A = +100.2 [+92.5] Hz, 4 J BB = +10.2 [+7.4] Hz; Raman (250 mw, 25 C, cm -1 ): 3141 (8), 3055 (63), 2984 (35), 2903 (79), 1580 (62), 1436 (9), 1405 (11), 1190 (9), 1164 (14), 1076 (26), 1024 (48), 999 (53), 706 (14), 615 (4), 478 (9), 421 (17), 346 (27), 288 (5), 262 (6), 208 (5), 193 (9), 154 (11), 119 (100), 84 (83); FT- IR (powder, CsI): ν = 3070 (m), 3052 (m), 2998 (s), 2906 (s), 2656 (vw), 2602 (vw), 2575 (vw), 2466 (vw), 2348 (vw), 2323 (vw), 2290 (vw), 2252 (w), 2154 (vw), 1960 (w), 1893 (vw), 1814 (w), 1775 (vw), 1664 (w), 1581 (m), 1569 (m), 1478 (s), 1434 (vs), 1406 (s), 1310 (s), 1285 (s), 1270 (m), 1228 (m), 1186 (s), 1160 (s), 1147 (m), 1133 (m), 1078 (s), 1070 (s), 1023 (s), 998 (vs), 903 (vs), 851 (m), 794 (m), 743 (vs), 693 (vs), 616 (vw), 559 (w), 477 (m), 373 (s), 293 (w), 281 (w), 264 (w); elemental analysis for C 28 H 32 Cl 8 Ga 2 P 6 (977.46): calcd. C 34.41, H 3.30; found: C 34.25, H 3.28. 4

2. NMR Spectroscopic Details Figure S1. Experimental (upper) and simulated (lower) 31 P{ 1 H} NMR spectra of 6a (in CH 2 Cl 2, impurities due to decomposition of 6a are marked with an asterisk). 5

Figure S2. Experimental spectra of 6a at two different temperatures in CH 2 Cl 2 ; upper: 185K and lower: 300K (101.26 MHz). 6

Figure S3. 31 P MAS spectrum of 6b (162.02 MHz). 7

Figure S4. 1 H{ 31 P}-NMR spectra of 6b dissolved in d 3 -MeCN at 268 K showing the presence of two symmetric species 6c (singlet, 1.88 ppm TB conformer) and 6b (two singlets, 1.85 and 2.26 ppm, eq./axial position chair conformer) in a ratio of approximately 1 : 3 (impurities due to decomposition of 6b and 6c are marked with and asterisk). 8

Figure S5. 31 P{ 1 H}-NMR spectra of 6c after quickly dissolving in CD 2 Cl 2 /CD 3 CN (4:1) and warming from 200 to 290K. The assignments of the resonances is indicated: 6b and 6c see text; 7b [Me 2 Ph 4 Ph 5 ][GaCl 4 ], complex multiplet ( 31 P A [δ] = +26 ppm, 31 P B [δ] = -29 ppm) (2); 8b [Me 2 PPMe 2 Cl][GaCl 4 ], dd ( 31 P A [δ] = +103 ppm, 31 P B [δ] = -29 ppm, J P,P = 340 Hz); the asterisk indicates Me 2 (Cl)P- GaCl 3 adduct (s, d = 57 ppm) (3). 9

3. Crystallographic Details Table S1. Crystallographic Data of 6a, 6b*2CDCl 3 and 6c*3CH 2 Cl 2. 6a 6b*2CDCl 3 6b*3CH 2 Cl 2 Formula C 48 H 40 P 6 Ga 2 Cl 8 C 30 H 32 P 6 D 2 Ga 2 Cl 14 C 31 H 38 P 6 Ga 2 Cl 14 MG [g mol 1 ] 1125.66 609.07 616.09 Color, habit Colorless, irregular Colorless, irregular Colorless, irregular Crystal System Monoclinic Monoclinic Monoclinic Space group Cc P2 1 /n C2/c a [Å] 11.396(9) 12.914(3) 28.057(7) b [Å] 25.90(2) 11.688(2) 11.493(3) c [Å] 18.727(15) 17.770(4) 18.479(6) α [ ] 90.0 90.0 90.0 β [ ] 104.566(14) 111.189(4) 119.470(7) γ [ ] 90.0 90.0 90.0 V [Å 3 ] 5349(8) 2500.8(9) 5188(2) Z 4 2 4 T [K] 173(1) 173(1) 173(1) Crystal size [mm] 0.45x0.35x0.10 0.40x0.30x0.10 0.40x0.30x0.20 ρ c [mg m 3 ] 1.522 1.618 1.578 F(000) 2464 1208 2456 λ MoKα, Å 0.71073 0.71073 0.71073 θ min [ ] θ max [ ] 1.57 27.50 2.13 27.50 1.67 24.99 Index range 14 h 13 32 k 33 23 l 20 15 h 16 14 k 13 20 l 22 30 h 32 13 k 13 18 l 21 µ [mm 1 ] 1.620 2.041 1.969 Absorption correction SADABS SADABS SADABS Reflections collected 18192 16914 12481 Reflections unique 8670 5629 4341 R int 0.0314 0.0294 0.0261 Reflection obs. [F > 2σ(F)] 7936 4467 3110 Residual density [e Å 3 ] 0.404, 0.265 0.838, 0.611 0.818, 0.389 Parameters 577 303 273 GooF 0.900 1.064 1.116 R 1 [I > 2σ(I)] 0.0251 0.0305 0.0669 wr 2 (all data) 0.0561 0.0830 0.1634 CCDC 607203 607204 607205 In the case of 6b*3CH 2 Cl 2 single crystals were coated with Paratone-N oil, mounted using a 20 micron cryo-loop and frozen in the cold nitrogen stream of the goniometer. A hemisphere of data was collected on a Bruker AXS P4/SMART 1000 diffractometer using ω and θ scans with a scan width of 0.3 and 10 s exposure times. 10

The detector distance was 6 cm. The data were reduced (SAINT) (4) and corrected for absorption (SADABS) (5). The crystal was a multiple twin, but only data of the major component gave satisfactory solution and refinement. The structure was solved by direct methods and refined by full-matrix least squares on F 2 (SHELXTL) (6). The solvent molecules were disordered, one superimposed on itself. The site occupancy was determined using an isotropic model as 0.7 (Cl(5), Cl(6)) and 0.3 (Cl(5 ), Cl(6 )) and fixed in subsequent refinement cycles. Site occupancies for C(16), Cl(7) and Cl(8) were fixed at 0.5. All non-hydrogen atoms were refined anisotropically. Hydrogen atoms were included in calculated positions and refined using a riding model. Solvent molecule hydrogen atoms were omitted. Table S2. Bond lengths [Å] and angles [ ] for 6a ([Ph 8 P 6 ][GaCl 4 ] 2 ). P(1)-C(1) 1.792(3) C(23)-C(24) 1.384(5) P(1)-C(7) 1.801(3) C(23)-H(23) 0.9500 P(1)-P(6) 2.2331(18) C(24)-H(24) 0.9500 P(1)-P(2) 2.242(2) C(25)-C(26) 1.384(4) P(2)-C(13) 1.835(3) C(25)-C(30) 1.401(4) P(2)-P(3) 2.2305(16) C(26)-C(27) 1.387(4) P(3)-C(19) 1.826(3) C(26)-H(26) 0.9500 P(3)-P(4) 2.2170(18) C(27)-C(28) 1.380(4) P(4)-C(31) 1.788(3) C(27)-H(27) 0.9500 P(4)-C(25) 1.801(3) C(28)-C(29) 1.378(5) P(4)-P(5) 2.2332(19) C(28)-H(28) 0.9500 P(5)-C(37) 1.835(3) C(29)-C(30) 1.390(4) P(5)-P(6) 2.2274(14) C(29)-H(29) 0.9500 P(6)-C(43) 1.827(3) C(30)-H(30) 0.9500 C(1)-C(6) 1.393(4) C(31)-C(32) 1.400(4) C(1)-C(2) 1.399(3) C(31)-C(36) 1.411(3) C(2)-C(3) 1.379(4) C(32)-C(33) 1.371(4) C(2)-H(2) 0.9500 C(32)-H(32) 0.9500 C(3)-C(4) 1.388(5) C(33)-C(34) 1.385(4) C(3)-H(3) 0.9500 C(33)-H(33) 0.9500 C(4)-C(5) 1.352(5) C(34)-C(35) 1.373(5) C(4)-H(4) 0.9500 C(34)-H(34) 0.9500 C(5)-C(6) 1.385(4) C(35)-C(36) 1.384(4) C(5)-H(5) 0.9500 C(35)-H(35) 0.9500 C(6)-H(6) 0.9500 C(36)-H(36) 0.9500 C(7)-C(12) 1.394(4) C(37)-C(42) 1.388(4) C(7)-C(8) 1.395(4) C(37)-C(38) 1.398(4) C(8)-C(9) 1.385(4) C(38)-C(39) 1.390(5) C(8)-H(8) 0.9500 C(38)-H(38) 0.9500 C(9)-C(10) 1.378(5) C(39)-C(40) 1.373(5) C(9)-H(9) 0.9500 C(39)-H(39) 0.9500 11

C(10)-C(11) 1.385(5) C(40)-C(41) 1.387(5) C(10)-H(10) 0.9500 C(40)-H(40) 0.9500 C(11)-C(12) 1.390(4) C(41)-C(42) 1.395(4) C(11)-H(11) 0.9500 C(41)-H(41) 0.9500 C(12)-H(12) 0.9500 C(42)-H(42) 0.9500 C(13)-C(14) 1.394(4) C(43)-C(48) 1.387(4) C(13)-C(18) 1.395(3) C(43)-C(44) 1.399(4) C(14)-C(15) 1.385(4) C(44)-C(45) 1.377(5) C(14)-H(14) 0.9500 C(44)-H(44) 0.9500 C(15)-C(16) 1.386(4) C(45)-C(46) 1.388(5) C(15)-H(15) 0.9500 C(45)-H(45) 0.9500 C(16)-C(17) 1.379(5) C(46)-C(47) 1.374(4) C(16)-H(16) 0.9500 C(46)-H(46) 0.9500 C(17)-C(18) 1.382(4) C(47)-C(48) 1.390(4) C(17)-H(17) 0.9500 C(47)-H(47) 0.9500 C(18)-H(18) 0.9500 C(48)-H(48) 0.9500 C(19)-C(20) 1.392(4) Ga(1)-Cl(3) 2.1674(16) C(19)-C(24) 1.395(4) Ga(1)-Cl(1) 2.1737(14) C(20)-C(21) 1.386(5) Ga(1)-Cl(4) 2.1747(15) C(20)-H(20) 0.9500 Ga(1)-Cl(2) 2.1756(16) C(21)-C(22) 1.375(5) Ga(2)-Cl(6) 2.1589(19) C(21)-H(21) 0.9500 Ga(2)-Cl(7) 2.1618(14) C(22)-C(23) 1.372(4) Ga(2)-Cl(8) 2.1663(18) C(22)-H(22) 0.9500 Ga(2)-Cl(5) 2.1882(18) C(1)-P(1)-C(7) 110.85(14) C(22)-C(23)-C(24) 120.2(3) C(1)-P(1)-P(6) 112.99(10) C(22)-C(23)-H(23) 119.9 C(7)-P(1)-P(6) 106.17(11) C(24)-C(23)-H(23) 119.9 C(1)-P(1)-P(2) 106.64(11) C(23)-C(24)-C(19) 119.9(3) C(7)-P(1)-P(2) 110.30(10) C(23)-C(24)-H(24) 120.0 P(6)-P(1)-P(2) 109.93(4) C(19)-C(24)-H(24) 120.0 C(13)-P(2)-P(3) 99.94(10) C(26)-C(25)-C(30) 120.2(3) C(13)-P(2)-P(1) 96.29(9) C(26)-C(25)-P(4) 119.8(2) P(3)-P(2)-P(1) 92.09(5) C(30)-C(25)-P(4) 119.7(2) C(19)-P(3)-P(4) 101.39(9) C(25)-C(26)-C(27) 120.3(3) C(19)-P(3)-P(2) 102.04(9) C(25)-C(26)-H(26) 119.8 P(4)-P(3)-P(2) 95.64(6) C(27)-C(26)-H(26) 119.8 C(31)-P(4)-C(25) 110.32(14) C(28)-C(27)-C(26) 119.5(3) C(31)-P(4)-P(3) 105.14(10) C(28)-C(27)-H(27) 120.3 C(25)-P(4)-P(3) 114.70(10) C(26)-C(27)-H(27) 120.3 C(31)-P(4)-P(5) 111.35(11) C(29)-C(28)-C(27) 120.7(3) C(25)-P(4)-P(5) 106.15(11) C(29)-C(28)-H(28) 119.7 P(3)-P(4)-P(5) 109.27(4) C(27)-C(28)-H(28) 119.7 C(37)-P(5)-P(6) 100.46(10) C(28)-C(29)-C(30) 120.6(3) C(37)-P(5)-P(4) 94.83(10) C(28)-C(29)-H(29) 119.7 P(6)-P(5)-P(4) 93.16(6) C(30)-C(29)-H(29) 119.7 C(43)-P(6)-P(5) 100.87(9) C(29)-C(30)-C(25) 118.7(3) C(43)-P(6)-P(1) 98.74(10) C(29)-C(30)-H(30) 120.7 P(5)-P(6)-P(1) 95.10(6) C(25)-C(30)-H(30) 120.7 C(6)-C(1)-C(2) 120.0(3) C(32)-C(31)-C(36) 119.6(3) C(6)-C(1)-P(1) 120.31(19) C(32)-C(31)-P(4) 120.40(19) C(2)-C(1)-P(1) 119.6(2) C(36)-C(31)-P(4) 119.5(2) C(3)-C(2)-C(1) 118.6(3) C(33)-C(32)-C(31) 119.8(3) C(3)-C(2)-H(2) 120.7 C(33)-C(32)-H(32) 120.1 12

C(1)-C(2)-H(2) 120.7 C(31)-C(32)-H(32) 120.1 C(2)-C(3)-C(4) 120.8(3) C(32)-C(33)-C(34) 120.2(3) C(2)-C(3)-H(3) 119.6 C(32)-C(33)-H(33) 119.9 C(4)-C(3)-H(3) 119.6 C(34)-C(33)-H(33) 119.9 C(5)-C(4)-C(3) 120.5(3) C(35)-C(34)-C(33) 121.0(3) C(5)-C(4)-H(4) 119.8 C(35)-C(34)-H(34) 119.5 C(3)-C(4)-H(4) 119.8 C(33)-C(34)-H(34) 119.5 C(4)-C(5)-C(6) 120.4(3) C(34)-C(35)-C(36) 120.0(3) C(4)-C(5)-H(5) 119.8 C(34)-C(35)-H(35) 120.0 C(6)-C(5)-H(5) 119.8 C(36)-C(35)-H(35) 120.0 C(5)-C(6)-C(1) 119.7(3) C(35)-C(36)-C(31) 119.4(3) C(5)-C(6)-H(6) 120.1 C(35)-C(36)-H(36) 120.3 C(1)-C(6)-H(6) 120.1 C(31)-C(36)-H(36) 120.3 C(12)-C(7)-C(8) 120.9(2) C(42)-C(37)-C(38) 119.4(3) C(12)-C(7)-P(1) 118.6(2) C(42)-C(37)-P(5) 124.4(2) C(8)-C(7)-P(1) 120.0(2) C(38)-C(37)-P(5) 116.0(2) C(9)-C(8)-C(7) 118.7(3) C(39)-C(38)-C(37) 119.4(3) C(9)-C(8)-H(8) 120.7 C(39)-C(38)-H(38) 120.3 C(7)-C(8)-H(8) 120.7 C(37)-C(38)-H(38) 120.3 C(10)-C(9)-C(8) 120.8(3) C(40)-C(39)-C(38) 121.1(3) C(10)-C(9)-H(9) 119.6 C(40)-C(39)-H(39) 119.4 C(8)-C(9)-H(9) 119.6 C(38)-C(39)-H(39) 119.4 C(9)-C(10)-C(11) 120.6(3) C(39)-C(40)-C(41) 119.8(3) C(9)-C(10)-H(10) 119.7 C(39)-C(40)-H(40) 120.1 C(11)-C(10)-H(10) 119.7 C(41)-C(40)-H(40) 120.1 C(10)-C(11)-C(12) 119.7(3) C(40)-C(41)-C(42) 119.9(3) C(10)-C(11)-H(11) 120.1 C(40)-C(41)-H(41) 120.1 C(12)-C(11)-H(11) 120.1 C(42)-C(41)-H(41) 120.1 C(11)-C(12)-C(7) 119.3(3) C(37)-C(42)-C(41) 120.3(3) C(11)-C(12)-H(12) 120.3 C(37)-C(42)-H(42) 119.8 C(7)-C(12)-H(12) 120.3 C(41)-C(42)-H(42) 119.8 C(14)-C(13)-C(18) 119.0(3) C(48)-C(43)-C(44) 119.3(3) C(14)-C(13)-P(2) 116.4(2) C(48)-C(43)-P(6) 115.0(2) C(18)-C(13)-P(2) 124.6(2) C(44)-C(43)-P(6) 125.7(2) C(15)-C(14)-C(13) 120.5(3) C(45)-C(44)-C(43) 120.0(3) C(15)-C(14)-H(14) 119.8 C(45)-C(44)-H(44) 120.0 C(13)-C(14)-H(14) 119.8 C(43)-C(44)-H(44) 120.0 C(14)-C(15)-C(16) 119.6(3) C(44)-C(45)-C(46) 120.0(3) C(14)-C(15)-H(15) 120.2 C(44)-C(45)-H(45) 120.0 C(16)-C(15)-H(15) 120.2 C(46)-C(45)-H(45) 120.0 C(17)-C(16)-C(15) 120.5(3) C(47)-C(46)-C(45) 120.5(3) C(17)-C(16)-H(16) 119.8 C(47)-C(46)-H(46) 119.7 C(15)-C(16)-H(16) 119.8 C(45)-C(46)-H(46) 119.7 C(16)-C(17)-C(18) 120.0(3) C(46)-C(47)-C(48) 119.7(3) C(16)-C(17)-H(17) 120.0 C(46)-C(47)-H(47) 120.2 C(18)-C(17)-H(17) 120.0 C(48)-C(47)-H(47) 120.2 C(17)-C(18)-C(13) 120.4(3) C(43)-C(48)-C(47) 120.4(3) C(17)-C(18)-H(18) 119.8 C(43)-C(48)-H(48) 119.8 C(13)-C(18)-H(18) 119.8 C(47)-C(48)-H(48) 119.8 C(20)-C(19)-C(24) 119.2(3) Cl(3)-Ga(1)-Cl(1) 111.21(6) C(20)-C(19)-P(3) 114.9(2) Cl(3)-Ga(1)-Cl(4) 109.25(6) C(24)-C(19)-P(3) 125.9(2) Cl(1)-Ga(1)-Cl(4) 108.10(7) C(21)-C(20)-C(19) 120.2(3) Cl(3)-Ga(1)-Cl(2) 108.95(7) C(21)-C(20)-H(20) 119.9 Cl(1)-Ga(1)-Cl(2) 110.23(6) 13

C(19)-C(20)-H(20) 119.9 Cl(4)-Ga(1)-Cl(2) 109.07(5) C(22)-C(21)-C(20) 119.8(3) Cl(6)-Ga(2)-Cl(7) 111.16(6) C(22)-C(21)-H(21) 120.1 Cl(6)-Ga(2)-Cl(8) 109.38(9) C(20)-C(21)-H(21) 120.1 Cl(7)-Ga(2)-Cl(8) 108.90(6) C(23)-C(22)-C(21) 120.6(3) Cl(6)-Ga(2)-Cl(5) 109.66(6) C(23)-C(22)-H(22) 119.7 Cl(7)-Ga(2)-Cl(5) 107.21(7) C(21)-C(22)-H(22) 119.7 Cl(8)-Ga(2)-Cl(5) 110.52(6) Table S3. Bond lengths [Å] and angles [ ] for 6b (1/2[Me 4 Ph 4 P 6 ][GaCl 4 ]*CDCl 3 ). P(1)-C(2) 1.795(2) C(7)-H(7) 0.95(3) P(1)-C(1) 1.802(3) C(7)-C(8) 1.383(4) P(1)-P(2) 2.2014(9) C(8)-H(8) 1.01(3) P(1)-P(3) i 2.2081(9) C(9)-C(10) 1.394(3) P(2)-C(3) 1.839(2) C(9)-C(14) 1.399(3) P(2)-P(3) 2.2308(9) C(10)-H(10) 0.90(3) P(3)-C(9) 1.837(2) C(10)-C(11) 1.389(4) P(3)-P(1) i 2.2081(9) C(11)-H(11) 0.94(3) C(1)-H(1C) 0.94(3) C(11)-C(12) 1.381(4) C(1)-H(1B) 0.95(3) C(12)-H(12) 0.94(3) C(1)-H(1A) 0.96(4) C(12)-C(13) 1.378(4) C(2)-H(2C) 0.96(3) C(13)-H(13) 0.91(3) C(2)-H(2B) 0.97(3) C(13)-C(14) 1.378(4) C(2)-H(2A) 0.98(3) C(14)-H(14) 0.95(3) C(3)-C(8) 1.391(3) Ga-Cl(3) 2.1674(8) C(3)-C(4) 1.393(3) Ga-Cl(2) 2.1723(7) C(4)-H(4) 0.91(2) Ga-Cl(1) 2.1779(8) C(4)-C(5) 1.380(4) Ga-Cl(4) 2.1831(8) C(5)-H(5) 0.96(3) C(15)-Cl(5) 1.753(3) C(5)-C(6) 1.377(4) C(15)-Cl(7) 1.758(3) C(6)-H(6) 0.99(3) C(15)-Cl(6) 1.759(3) C(6)-C(7) 1.375(4) C(15)-D 0.93(3) C(2)-P(1)-C(1) 108.89(14) H(7)-C(7)-C(6) 124(2) C(2)-P(1)-P(2) 115.80(10) H(7)-C(7)-C(8) 115(2) C(1)-P(1)-P(2) 104.87(10) C(6)-C(7)-C(8) 120.6(3) C(2)-P(1)-P(3) i 116.65(10) H(8)-C(8)-C(7) 120.7(15) C(1)-P(1)-P(3) i 104.35(10) H(8)-C(8)-C(3) 119.4(15) P(2)-P(1)-P(3) i 105.10(3) C(7)-C(8)-C(3) 119.8(3) C(3)-P(2)-P(1) 99.30(8) C(10)-C(9)-C(14) 119.5(2) C(3)-P(2)-P(3) 100.02(8) C(10)-C(9)-P(3) 116.34(17) P(1)-P(2)-P(3) 98.22(3) C(14)-C(9)-P(3) 124.14(17) C(9)-P(3)-P(1) i 99.59(8) H(10)-C(10)-C(11) 120.3(17) C(9)-P(3)-P(2) 97.65(8) H(10)-C(10)-C(9) 120.0(17) P(1)#1-P(3)-P(2) 97.31(3) C(11)-C(10)-C(9) 119.7(2) H(1C)-C(1)-H(1B) 110(3) H(11)-C(11)-C(12) 119.9(17) H(1C)-C(1)-H(1A) 109(3) H(11)-C(11)-C(10) 119.8(17) H(1B)-C(1)-H(1A) 113(3) C(12)-C(11)-C(10) 120.2(2) H(1C)-C(1)-P(1) 108.2(18) H(12)-C(12)-C(13) 119.2(18) H(1B)-C(1)-P(1) 108.8(19) H(12)-C(12)-C(11) 120.5(18) H(1A)-C(1)-P(1) 107(2) C(13)-C(12)-C(11) 120.2(3) H(2C)-C(2)-H(2B) 108(2) H(13)-C(13)-C(12) 120.6(19) 14

H(2C)-C(2)-H(2A) 111(2) H(13)-C(13)-C(14) 118.7(19) H(2B)-C(2)-H(2A) 110(2) C(12)-C(13)-C(14) 120.5(2) H(2C)-C(2)-P(1) 109.5(17) H(14)-C(14)-C(13) 119.2(16) H(2B)-C(2)-P(1) 110.9(16) H(14)-C(14)-C(9) 120.8(16) H(2A)-C(2)-P(1) 107.3(16) C(13)-C(14)-C(9) 119.9(2) C(8)-C(3)-C(4) 119.2(2) Cl(3)-Ga-Cl(2) 110.72(3) C(8)-C(3)-P(2) 125.50(19) Cl(3)-Ga-Cl(1) 109.26(3) C(4)-C(3)-P(2) 115.28(18) Cl(2)-Ga-Cl(1) 108.66(3) H(4)-C(4)-C(5) 120.1(16) Cl(3)-Ga-Cl(4) 108.26(3) H(4)-C(4)-C(3) 119.8(16) Cl(2)-Ga-Cl(4) 110.00(3) C(5)-C(4)-C(3) 120.2(2) Cl(1)-Ga-Cl(4) 109.94(3) H(5)-C(5)-C(6) 122.3(19) Cl(5)-C(15)-Cl(7) 111.20(18) H(5)-C(5)-C(4) 117.4(19) Cl(5)-C(15)-Cl(6) 111.05(17) C(6)-C(5)-C(4) 120.3(3) Cl(7)-C(15)-Cl(6) 110.06(16) H(6)-C(6)-C(7) 122.4(17) Cl(5)-C(15)-D 108.4(19) H(6)-C(6)-C(5) 117.7(17) Cl(7)-C(15)-D 108.5(19) C(7)-C(6)-C(5) 119.9(3) Cl(6)-C(15)-D 107.5(18) 15

4. Newman Projection Figure S6. Newman projection of 6a down P1- P2, P1- P6, P2- P3, P3- P4, P4- P5 and P5- P6. 16

Figure S7. Newman projection of 6b down P1- P2, P2- P3, P1- P3 i [Symmetry code: (i) -x, -y, -2+z]. 17

5. References 1. W. A. Henderson, M. Epstein, F. S. Seichter, J. Am. Chem. Soc. 1963, 85, 2462. 2. N. Burford, C. A. Dyker, M. D. Lumsden, A. Decken, Angew. Chem. 2005, 117, 6355; Angew. Chem. Int. Ed. 2005, 44, 6196. 3. N. Burford, T. S. Cameron, D. J. LeBlanc, P. Losier, S. Sereda, G. Wu, Organometallics 1997, 16, 4712. 4. SAINT 6.02, 1997-1999, Bruker AXS, Inc., Madison, Wisconsin, USA. 5. SADABS George Sheldrick, 1999, Bruker AXS, Inc., Madison, Wisconsin, USA. 6. SHELXTL 6.14, 2000-2003, Bruker AXS, Inc., Madison, Wisconsin, USA. 18