# Supplementary Material (ESI) for ChemComm # This journal is © The Royal Society of Chemistry 2000 # CCDC Number: 182/1624 data_sibina _audit_creation_method SHELXL-97 _chemical_name_systematic ; ? ; _chemical_name_common ? _chemical_formula_moiety ? _chemical_formula_sum 'C31 H30 O2 Si' _chemical_formula_weight 462.64 loop_ _atom_type_symbol _atom_type_description _atom_type_scat_dispersion_real _atom_type_scat_dispersion_imag _atom_type_scat_source 'Si' 'Si' 0.2541 0.3302 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'O' 'O' 0.0492 0.0322 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'C' 'C' 0.0181 0.0091 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'H' 'H' 0.0000 0.0000 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' _symmetry_cell_setting Orthorhombic _symmetry_space_group_name_H-M P2(1)2(1)2(1) loop_ _symmetry_equiv_pos_as_xyz 'x, y, z' '-x+1/2, -y, z+1/2' '-x, y+1/2, -z+1/2' 'x+1/2, -y+1/2, -z' _cell_length_a 8.3530(10) _cell_length_b 13.3170(10) _cell_length_c 23.5330(10) _cell_angle_alpha 90.00 _cell_angle_beta 90.00 _cell_angle_gamma 90.00 _cell_volume 2617.7(4) _cell_formula_units_Z 4 _cell_measurement_temperature 293(2) _cell_measurement_reflns_used 25 _cell_measurement_theta_min 21.6 _cell_measurement_theta_max 37.0 _exptl_crystal_description 'transparent needle' _exptl_crystal_colour colourless _exptl_crystal_size_max 0.39 _exptl_crystal_size_mid 0.20 _exptl_crystal_size_min 0.15 _exptl_crystal_density_meas ? _exptl_crystal_density_diffrn 1.174 _exptl_crystal_density_method 'not measured' _exptl_crystal_F_000 984 _exptl_absorpt_coefficient_mu 0.976 _exptl_absorpt_correction_type numeric _exptl_absorpt_correction_T_min 0.64 _exptl_absorpt_correction_T_max 0.85 _exptl_special_details ; ? ; _diffrn_ambient_temperature 293(2) _diffrn_radiation_wavelength 1.54184 _diffrn_radiation_type CuK\a _diffrn_radiation_source 'fine-focus sealed tube' _diffrn_radiation_monochromator graphite _diffrn_measurement_device_type 'CAD4 Enraf-Nonius' _diffrn_measurement_method 'theta-2theta-scan' _diffrn_detector_area_resol_mean ? _diffrn_standards_number 2 _diffrn_standards_interval_count ? _diffrn_standards_interval_time 120min _diffrn_standards_decay_% 0.4 _diffrn_reflns_number 2663 _diffrn_reflns_av_R_equivalents 0.0290 _diffrn_reflns_av_sigmaI/netI 0.0210 _diffrn_reflns_limit_h_min 0 _diffrn_reflns_limit_h_max 10 _diffrn_reflns_limit_k_min -16 _diffrn_reflns_limit_k_max 3 _diffrn_reflns_limit_l_min 0 _diffrn_reflns_limit_l_max 28 _diffrn_reflns_theta_min 3.76 _diffrn_reflns_theta_max 69.85 _reflns_number_total 2606 _reflns_number_gt 2606 _reflns_threshold_expression >2sigma(I) _computing_data_collection 'Molen CAD4' _computing_cell_refinement 'Gitkon, J.Eck, 1995' _computing_data_reduction 'Molen CAD4' _computing_structure_solution 'SIR-92 (Giacovazzo, 1993)' _computing_structure_refinement 'SHELXL-97 (Sheldrick, 1997)' _computing_molecular_graphics ORTEP3 _computing_publication_material SHELXL-97 _refine_special_details ; Refinement of F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ > 2sigma(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. ; _refine_ls_structure_factor_coef Fsqd _refine_ls_matrix_type full _refine_ls_weighting_scheme 'calc w=1/[\s^2^(Fo^2^)+(0.1630P)^2^+0.7462P] where P=(Fo^2^+2Fc^2^)/3' _atom_sites_solution_primary direct _atom_sites_solution_secondary difmap _atom_sites_solution_hydrogens difmap _refine_ls_hydrogen_treatment mixed _refine_ls_extinction_method SHELXL _refine_ls_extinction_coef 0.0041(5) _refine_ls_extinction_expression 'Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^' _refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881' _refine_ls_abs_structure_Flack -0.08(4) _refine_ls_number_reflns 2606 _refine_ls_number_parameters 392 _refine_ls_number_restraints 0 _refine_ls_R_factor_all 0.0356 _refine_ls_R_factor_gt 0.0356 _refine_ls_wR_factor_ref 0.1063 _refine_ls_wR_factor_gt 0.1063 _refine_ls_goodness_of_fit_ref 0.561 _refine_ls_restrained_S_all 0.561 _refine_ls_shift/su_max 0.002 _refine_ls_shift/su_mean 0.000 loop_ _atom_site_label _atom_site_type_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv _atom_site_adp_type _atom_site_occupancy _atom_site_calc_flag _atom_site_refinement_flags _atom_site_disorder_assembly _atom_site_disorder_group Si2 Si 1.12809(9) 0.33412(6) 0.15259(3) 0.0564(2) Uani 1 d . . . O2 O 0.9976(3) 0.42522(17) 0.14077(9) 0.0736(6) Uani 1 d . . . O12 O 1.0113(4) 0.7207(3) 0.17444(14) 0.0990(9) Uani 1 d . . . C1 C 0.8099(3) 0.5532(2) 0.15064(12) 0.0534(5) Uani 1 d . . . C2 C 0.8687(3) 0.4622(2) 0.16845(11) 0.0581(6) Uani 1 d . . . C3 C 0.7978(4) 0.4102(3) 0.21417(13) 0.0686(8) Uani 1 d . . . C4 C 0.6671(4) 0.4492(3) 0.24084(13) 0.0679(8) Uani 1 d . . . C4A C 0.6005(3) 0.5408(2) 0.22299(11) 0.0599(7) Uani 1 d . . . C5 C 0.4603(4) 0.5803(3) 0.24962(15) 0.0774(9) Uani 1 d . . . C6 C 0.3895(5) 0.6650(3) 0.22849(19) 0.0912(11) Uani 1 d . . . C7 C 0.4528(5) 0.7130(3) 0.1822(2) 0.0873(11) Uani 1 d . . . C8 C 0.5929(4) 0.6804(2) 0.15681(15) 0.0719(8) Uani 1 d . . . C8A C 0.6682(3) 0.5920(2) 0.17696(11) 0.0545(6) Uani 1 d . . . C11 C 0.8949(3) 0.60988(19) 0.10467(12) 0.0566(6) Uani 1 d . . . C12 C 0.9922(5) 0.6887(3) 0.11947(16) 0.0753(8) Uani 1 d . . . C13 C 1.0826(5) 0.7402(3) 0.0778(2) 0.0934(13) Uani 1 d . . . C14 C 1.0760(5) 0.7123(3) 0.0233(2) 0.0947(12) Uani 1 d . . . C14A C 0.9776(4) 0.6318(2) 0.00472(14) 0.0711(8) Uani 1 d . . . C15 C 0.9685(5) 0.6011(3) -0.05183(16) 0.0846(10) Uani 1 d . . . C16 C 0.8663(6) 0.5269(4) -0.06850(15) 0.0917(11) Uani 1 d . . . C17 C 0.7705(5) 0.4794(3) -0.02836(15) 0.0819(10) Uani 1 d . . . C18 C 0.7802(4) 0.5050(2) 0.02811(14) 0.0667(7) Uani 1 d . . . C18A C 0.8835(3) 0.5820(2) 0.04680(11) 0.0570(6) Uani 1 d . . . C20 C 1.2232(5) 0.3484(4) 0.22319(14) 0.0861(10) Uani 1 d . . . H201 H 1.1461 0.3341 0.2524 0.121(16) Uiso 1 calc R . . H202 H 1.2612 0.4160 0.2275 0.16(2) Uiso 1 calc R . . H203 H 1.3115 0.3026 0.2263 0.26(4) Uiso 1 calc R . . C21 C 1.2734(3) 0.3523(3) 0.09317(13) 0.0671(7) Uani 1 d . . . C22 C 1.4186(5) 0.2811(4) 0.10119(19) 0.0962(13) Uani 1 d . . . H221 H 1.3818 0.2129 0.1033 0.126(19) Uiso 1 calc R . . H222 H 1.4737 0.2982 0.1357 0.123(17) Uiso 1 calc R . . H223 H 1.4903 0.2882 0.0696 0.17(2) Uiso 1 calc R . . C23 C 1.1924(6) 0.3290(4) 0.03640(14) 0.0951(12) Uani 1 d . . . H231 H 1.2675 0.3388 0.0060 0.120(15) Uiso 1 calc R . . H232 H 1.1025 0.3730 0.0312 0.122(17) Uiso 1 calc R . . H233 H 1.1563 0.2605 0.0363 0.13(2) Uiso 1 calc R . . C24 C 1.3331(5) 0.4606(3) 0.0928(2) 0.0951(12) Uani 1 d . . . H241 H 1.3987 0.4714 0.0599 0.101(13) Uiso 1 calc R . . H242 H 1.3950 0.4730 0.1265 0.17(3) Uiso 1 calc R . . H243 H 1.2432 0.5055 0.0918 0.17(3) Uiso 1 calc R . . C25 C 1.0200(3) 0.2116(2) 0.14823(11) 0.0588(6) Uani 1 d . . . C26 C 1.0803(4) 0.1244(3) 0.17187(14) 0.0724(8) Uani 1 d . . . C27 C 1.0047(6) 0.0328(3) 0.16597(16) 0.0868(10) Uani 1 d . . . C28 C 0.8623(6) 0.0270(3) 0.13694(16) 0.0906(11) Uani 1 d . . . C29 C 0.7963(5) 0.1114(4) 0.11369(15) 0.0888(11) Uani 1 d . . . C30 C 0.8728(5) 0.2029(3) 0.11905(14) 0.0761(8) Uani 1 d . . . H3 H 0.841(4) 0.350(3) 0.2247(14) 0.073(10) Uiso 1 d . . . H4 H 0.621(5) 0.413(3) 0.2725(16) 0.092(11) Uiso 1 d . . . H5 H 0.417(5) 0.540(3) 0.2880(16) 0.088(11) Uiso 1 d . . . H6 H 0.285(6) 0.692(3) 0.2465(18) 0.115(15) Uiso 1 d . . . H7 H 0.403(7) 0.777(4) 0.169(2) 0.130(17) Uiso 1 d . . . H8 H 0.635(4) 0.718(2) 0.1196(13) 0.066(8) Uiso 1 d . . . H12 H 0.979(7) 0.673(4) 0.189(3) 0.13(2) Uiso 1 d . . . H13 H 1.142(6) 0.795(4) 0.0909(18) 0.109(14) Uiso 1 d . . . H14 H 1.130(6) 0.748(4) -0.0109(18) 0.109(13) Uiso 1 d . . . H15 H 1.053(6) 0.632(4) -0.085(2) 0.136(18) Uiso 1 d . . . H16 H 0.864(5) 0.507(3) -0.1088(17) 0.084(10) Uiso 1 d . . . H17 H 0.701(7) 0.421(4) -0.044(2) 0.125(16) Uiso 1 d . . . H18 H 0.725(4) 0.472(2) 0.0542(12) 0.053(7) Uiso 1 d . . . H26 H 1.168(5) 0.127(3) 0.1929(15) 0.087(11) Uiso 1 d . . . H27 H 1.055(5) -0.038(3) 0.1768(16) 0.090(11) Uiso 1 d . . . H28 H 0.818(5) -0.042(3) 0.1339(15) 0.093(12) Uiso 1 d . . . H29 H 0.695(6) 0.105(4) 0.0910(18) 0.111(14) Uiso 1 d . . . H30 H 0.824(8) 0.264(5) 0.100(2) 0.16(2) Uiso 1 d . . . loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_23 _atom_site_aniso_U_13 _atom_site_aniso_U_12 Si2 0.0531(3) 0.0560(4) 0.0600(3) 0.0033(3) 0.0018(3) 0.0063(3) O2 0.0681(12) 0.0683(13) 0.0843(13) 0.0215(11) 0.0240(10) 0.0214(11) O12 0.106(2) 0.092(2) 0.0990(18) -0.0239(17) 0.0038(16) -0.0341(18) C1 0.0507(11) 0.0481(12) 0.0614(12) 0.0012(11) 0.0053(11) -0.0012(11) C2 0.0502(12) 0.0580(14) 0.0662(13) 0.0049(11) 0.0100(11) 0.0039(13) C3 0.0685(17) 0.0623(16) 0.0750(17) 0.0181(15) 0.0114(14) 0.0081(15) C4 0.0652(17) 0.0730(19) 0.0654(15) 0.0059(15) 0.0134(13) -0.0043(15) C4A 0.0534(14) 0.0656(16) 0.0608(13) -0.0131(13) 0.0047(11) -0.0055(13) C5 0.0674(18) 0.080(2) 0.084(2) -0.0232(18) 0.0207(16) -0.0022(18) C6 0.077(2) 0.084(2) 0.112(3) -0.028(2) 0.019(2) 0.017(2) C7 0.081(2) 0.070(2) 0.111(3) -0.013(2) 0.005(2) 0.023(2) C8 0.0764(18) 0.0568(16) 0.0826(19) -0.0065(15) 0.0035(16) 0.0121(14) C8A 0.0508(13) 0.0499(12) 0.0629(13) -0.0089(11) -0.0003(10) -0.0018(11) C11 0.0524(13) 0.0450(12) 0.0724(15) 0.0062(11) 0.0061(12) 0.0009(12) C12 0.0763(19) 0.0593(17) 0.090(2) -0.0017(15) 0.0079(17) -0.0127(16) C13 0.095(3) 0.075(2) 0.110(3) 0.005(2) 0.010(2) -0.039(2) C14 0.099(3) 0.082(2) 0.104(3) 0.027(2) 0.017(2) -0.027(2) C14A 0.0697(17) 0.0641(18) 0.0794(18) 0.0224(15) 0.0092(15) -0.0005(16) C15 0.093(2) 0.085(2) 0.0757(19) 0.0221(18) 0.0142(18) 0.006(2) C16 0.111(3) 0.095(3) 0.0687(18) 0.0082(19) 0.000(2) 0.013(3) C17 0.093(2) 0.076(2) 0.0769(19) 0.0007(18) -0.0086(18) -0.003(2) C18 0.0701(18) 0.0579(15) 0.0722(16) 0.0060(14) 0.0027(14) -0.0019(15) C18A 0.0550(13) 0.0468(12) 0.0691(15) 0.0113(12) 0.0059(12) 0.0051(12) C20 0.100(3) 0.092(3) 0.0668(18) -0.0026(18) -0.0051(17) -0.018(2) C21 0.0538(14) 0.0775(19) 0.0702(15) 0.0001(15) 0.0075(12) 0.0077(15) C22 0.070(2) 0.123(4) 0.096(3) 0.000(2) 0.0114(19) 0.032(3) C23 0.095(2) 0.127(4) 0.0631(17) 0.003(2) 0.0075(17) 0.004(3) C24 0.080(2) 0.095(3) 0.111(3) 0.007(2) 0.026(2) -0.018(2) C25 0.0577(13) 0.0639(15) 0.0548(12) 0.0050(13) -0.0035(12) 0.0018(13) C26 0.0737(19) 0.0696(19) 0.0739(18) 0.0083(15) -0.0084(15) 0.0023(17) C27 0.106(3) 0.0632(19) 0.091(2) 0.0150(18) 0.002(2) -0.004(2) C28 0.104(3) 0.085(2) 0.083(2) 0.0054(19) 0.005(2) -0.033(3) C29 0.079(2) 0.113(3) 0.0749(19) 0.010(2) -0.0062(17) -0.029(2) C30 0.0678(17) 0.084(2) 0.0768(18) 0.0185(17) -0.0126(16) -0.0046(19) _geom_special_details ; All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. ; loop_ _geom_bond_atom_site_label_1 _geom_bond_atom_site_label_2 _geom_bond_distance _geom_bond_site_symmetry_2 _geom_bond_publ_flag Si2 O2 1.654(2) . ? Si2 C20 1.851(3) . ? Si2 C21 1.867(3) . ? Si2 C25 1.868(3) . ? O2 C2 1.352(3) . ? O12 C12 1.371(4) . ? O12 H12 0.77(6) . ? C1 C2 1.373(4) . ? C1 C8A 1.432(4) . ? C1 C11 1.498(4) . ? C2 C3 1.409(4) . ? C3 C4 1.362(4) . ? C3 H3 0.91(4) . ? C4 C4A 1.404(4) . ? C4 H4 0.97(4) . ? C4A C8A 1.400(4) . ? C4A C5 1.429(4) . ? C5 C6 1.367(6) . ? C5 H5 1.11(4) . ? C6 C7 1.369(6) . ? C6 H6 1.03(5) . ? C7 C8 1.384(5) . ? C7 H7 1.00(5) . ? C8 C8A 1.416(4) . ? C8 H8 1.07(3) . ? C11 C12 1.372(4) . ? C11 C18A 1.415(4) . ? C12 C13 1.415(5) . ? C13 C14 1.337(6) . ? C13 H13 0.93(5) . ? C14 C14A 1.419(5) . ? C14 H14 1.04(5) . ? C14A C15 1.394(5) . ? C14A C18A 1.428(4) . ? C15 C16 1.364(6) . ? C15 H15 1.13(5) . ? C16 C17 1.390(6) . ? C16 H16 0.99(4) . ? C17 C18 1.374(5) . ? C17 H17 1.04(5) . ? C18 C18A 1.410(4) . ? C18 H18 0.88(3) . ? C20 H201 0.9600 . ? C20 H202 0.9600 . ? C20 H203 0.9600 . ? C21 C24 1.526(5) . ? C21 C23 1.530(5) . ? C21 C22 1.550(5) . ? C22 H221 0.9600 . ? C22 H222 0.9600 . ? C22 H223 0.9600 . ? C23 H231 0.9600 . ? C23 H232 0.9600 . ? C23 H233 0.9600 . ? C24 H241 0.9600 . ? C24 H242 0.9600 . ? C24 H243 0.9600 . ? C25 C26 1.382(4) . ? C25 C30 1.413(4) . ? C26 C27 1.381(5) . ? C26 H26 0.89(4) . ? C27 C28 1.374(6) . ? C27 H27 1.07(4) . ? C28 C29 1.366(6) . ? C28 H28 0.99(4) . ? C29 C30 1.381(5) . ? C29 H29 1.00(5) . ? C30 H30 1.02(6) . ? loop_ _geom_angle_atom_site_label_1 _geom_angle_atom_site_label_2 _geom_angle_atom_site_label_3 _geom_angle _geom_angle_site_symmetry_1 _geom_angle_site_symmetry_3 _geom_angle_publ_flag O2 Si2 C20 110.97(18) . . ? O2 Si2 C21 101.98(12) . . ? C20 Si2 C21 112.32(17) . . ? O2 Si2 C25 108.26(13) . . ? C20 Si2 C25 110.28(16) . . ? C21 Si2 C25 112.71(14) . . ? C2 O2 Si2 135.31(19) . . ? C12 O12 H12 96(5) . . ? C2 C1 C8A 118.8(2) . . ? C2 C1 C11 119.7(2) . . ? C8A C1 C11 121.5(2) . . ? O2 C2 C1 117.3(2) . . ? O2 C2 C3 121.6(3) . . ? C1 C2 C3 121.1(3) . . ? C4 C3 C2 120.1(3) . . ? C4 C3 H3 122(2) . . ? C2 C3 H3 118(2) . . ? C3 C4 C4A 120.7(3) . . ? C3 C4 H4 119(2) . . ? C4A C4 H4 120(2) . . ? C8A C4A C4 119.6(3) . . ? C8A C4A C5 119.4(3) . . ? C4 C4A C5 120.9(3) . . ? C6 C5 C4A 119.9(4) . . ? C6 C5 H5 124(2) . . ? C4A C5 H5 116(2) . . ? C5 C6 C7 120.5(3) . . ? C5 C6 H6 120(3) . . ? C7 C6 H6 120(3) . . ? C6 C7 C8 121.6(4) . . ? C6 C7 H7 120(3) . . ? C8 C7 H7 119(3) . . ? C7 C8 C8A 119.5(3) . . ? C7 C8 H8 118.9(18) . . ? C8A C8 H8 121.3(18) . . ? C4A C8A C8 119.0(3) . . ? C4A C8A C1 119.5(3) . . ? C8 C8A C1 121.5(3) . . ? C12 C11 C18A 119.0(3) . . ? C12 C11 C1 118.9(3) . . ? C18A C11 C1 122.1(2) . . ? O12 C12 C11 123.1(3) . . ? O12 C12 C13 116.1(3) . . ? C11 C12 C13 120.8(3) . . ? C14 C13 C12 120.5(4) . . ? C14 C13 H13 124(3) . . ? C12 C13 H13 116(3) . . ? C13 C14 C14A 122.0(3) . . ? C13 C14 H14 127(3) . . ? C14A C14 H14 111(3) . . ? C15 C14A C14 123.2(3) . . ? C15 C14A C18A 119.7(3) . . ? C14 C14A C18A 117.1(3) . . ? C16 C15 C14A 121.4(3) . . ? C16 C15 H15 117(3) . . ? C14A C15 H15 121(3) . . ? C15 C16 C17 119.6(4) . . ? C15 C16 H16 119(2) . . ? C17 C16 H16 121(2) . . ? C18 C17 C16 120.7(4) . . ? C18 C17 H17 124(3) . . ? C16 C17 H17 115(3) . . ? C17 C18 C18A 121.2(3) . . ? C17 C18 H18 121.1(18) . . ? C18A C18 H18 117.7(18) . . ? C18 C18A C11 122.1(3) . . ? C18 C18A C14A 117.3(3) . . ? C11 C18A C14A 120.6(3) . . ? Si2 C20 H201 109.5 . . ? Si2 C20 H202 109.5 . . ? H201 C20 H202 109.5 . . ? Si2 C20 H203 109.5 . . ? H201 C20 H203 109.5 . . ? H202 C20 H203 109.5 . . ? C24 C21 C23 109.3(3) . . ? C24 C21 C22 108.8(3) . . ? C23 C21 C22 109.2(3) . . ? C24 C21 Si2 109.8(2) . . ? C23 C21 Si2 109.9(2) . . ? C22 C21 Si2 109.8(2) . . ? C21 C22 H221 109.5 . . ? C21 C22 H222 109.5 . . ? H221 C22 H222 109.5 . . ? C21 C22 H223 109.5 . . ? H221 C22 H223 109.5 . . ? H222 C22 H223 109.5 . . ? C21 C23 H231 109.5 . . ? C21 C23 H232 109.5 . . ? H231 C23 H232 109.5 . . ? C21 C23 H233 109.5 . . ? H231 C23 H233 109.5 . . ? H232 C23 H233 109.5 . . ? C21 C24 H241 109.5 . . ? C21 C24 H242 109.5 . . ? H241 C24 H242 109.5 . . ? C21 C24 H243 109.5 . . ? H241 C24 H243 109.5 . . ? H242 C24 H243 109.5 . . ? C26 C25 C30 116.3(3) . . ? C26 C25 Si2 122.4(2) . . ? C30 C25 Si2 121.3(2) . . ? C27 C26 C25 122.4(3) . . ? C27 C26 H26 118(3) . . ? C25 C26 H26 120(3) . . ? C28 C27 C26 119.7(4) . . ? C28 C27 H27 114(2) . . ? C26 C27 H27 125(2) . . ? C29 C28 C27 120.2(4) . . ? C29 C28 H28 125(2) . . ? C27 C28 H28 114(2) . . ? C28 C29 C30 120.1(3) . . ? C28 C29 H29 119(3) . . ? C30 C29 H29 121(3) . . ? C29 C30 C25 121.3(3) . . ? C29 C30 H30 119(4) . . ? C25 C30 H30 120(4) . . ? loop_ _geom_torsion_atom_site_label_1 _geom_torsion_atom_site_label_2 _geom_torsion_atom_site_label_3 _geom_torsion_atom_site_label_4 _geom_torsion _geom_torsion_site_symmetry_1 _geom_torsion_site_symmetry_2 _geom_torsion_site_symmetry_3 _geom_torsion_site_symmetry_4 _geom_torsion_publ_flag C20 Si2 O2 C2 -54.4(4) . . . . ? C21 Si2 O2 C2 -174.2(3) . . . . ? C25 Si2 O2 C2 66.8(3) . . . . ? Si2 O2 C2 C1 166.6(2) . . . . ? Si2 O2 C2 C3 -12.8(5) . . . . ? C8A C1 C2 O2 176.7(3) . . . . ? C11 C1 C2 O2 -3.7(4) . . . . ? C8A C1 C2 C3 -4.0(4) . . . . ? C11 C1 C2 C3 175.7(3) . . . . ? O2 C2 C3 C4 -179.5(3) . . . . ? C1 C2 C3 C4 1.2(5) . . . . ? C2 C3 C4 C4A 0.6(5) . . . . ? C3 C4 C4A C8A 0.6(4) . . . . ? C3 C4 C4A C5 177.9(3) . . . . ? C8A C4A C5 C6 2.9(5) . . . . ? C4 C4A C5 C6 -174.4(3) . . . . ? C4A C5 C6 C7 -0.6(6) . . . . ? C5 C6 C7 C8 -2.7(6) . . . . ? C6 C7 C8 C8A 3.6(6) . . . . ? C4 C4A C8A C8 175.4(3) . . . . ? C5 C4A C8A C8 -1.9(4) . . . . ? C4 C4A C8A C1 -3.4(4) . . . . ? C5 C4A C8A C1 179.2(3) . . . . ? C7 C8 C8A C4A -1.2(4) . . . . ? C7 C8 C8A C1 177.6(3) . . . . ? C2 C1 C8A C4A 5.0(4) . . . . ? C11 C1 C8A C4A -174.6(3) . . . . ? C2 C1 C8A C8 -173.7(3) . . . . ? C11 C1 C8A C8 6.6(4) . . . . ? C2 C1 C11 C12 -101.1(3) . . . . ? C8A C1 C11 C12 78.5(3) . . . . ? C2 C1 C11 C18A 76.1(4) . . . . ? C8A C1 C11 C18A -104.3(3) . . . . ? C18A C11 C12 O12 -179.7(3) . . . . ? C1 C11 C12 O12 -2.4(5) . . . . ? C18A C11 C12 C13 -1.2(5) . . . . ? C1 C11 C12 C13 176.0(3) . . . . ? O12 C12 C13 C14 177.8(4) . . . . ? C11 C12 C13 C14 -0.8(6) . . . . ? C12 C13 C14 C14A 1.0(7) . . . . ? C13 C14 C14A C15 180.0(4) . . . . ? C13 C14 C14A C18A 0.7(6) . . . . ? C14 C14A C15 C16 -176.5(4) . . . . ? C18A C14A C15 C16 2.8(6) . . . . ? C14A C15 C16 C17 -0.9(6) . . . . ? C15 C16 C17 C18 -1.4(6) . . . . ? C16 C17 C18 C18A 2.0(6) . . . . ? C17 C18 C18A C11 179.7(3) . . . . ? C17 C18 C18A C14A -0.1(5) . . . . ? C12 C11 C18A C18 -176.9(3) . . . . ? C1 C11 C18A C18 5.9(4) . . . . ? C12 C11 C18A C14A 3.0(4) . . . . ? C1 C11 C18A C14A -174.2(3) . . . . ? C15 C14A C18A C18 -2.2(5) . . . . ? C14 C14A C18A C18 177.2(3) . . . . ? C15 C14A C18A C11 178.0(3) . . . . ? C14 C14A C18A C11 -2.7(4) . . . . ? O2 Si2 C21 C24 53.4(3) . . . . ? C20 Si2 C21 C24 -65.5(3) . . . . ? C25 Si2 C21 C24 169.2(2) . . . . ? O2 Si2 C21 C23 -66.9(3) . . . . ? C20 Si2 C21 C23 174.2(3) . . . . ? C25 Si2 C21 C23 48.9(3) . . . . ? O2 Si2 C21 C22 173.0(3) . . . . ? C20 Si2 C21 C22 54.1(3) . . . . ? C25 Si2 C21 C22 -71.2(3) . . . . ? O2 Si2 C25 C26 -160.4(3) . . . . ? C20 Si2 C25 C26 -38.9(3) . . . . ? C21 Si2 C25 C26 87.5(3) . . . . ? O2 Si2 C25 C30 21.1(3) . . . . ? C20 Si2 C25 C30 142.7(3) . . . . ? C21 Si2 C25 C30 -90.9(3) . . . . ? C30 C25 C26 C27 2.1(5) . . . . ? Si2 C25 C26 C27 -176.4(3) . . . . ? C25 C26 C27 C28 -1.7(6) . . . . ? C26 C27 C28 C29 0.4(6) . . . . ? C27 C28 C29 C30 0.3(6) . . . . ? C28 C29 C30 C25 0.2(6) . . . . ? C26 C25 C30 C29 -1.4(5) . . . . ? Si2 C25 C30 C29 177.1(3) . . . . ? _diffrn_measured_fraction_theta_max 0.793 _diffrn_reflns_theta_full 69.85 _diffrn_measured_fraction_theta_full 0.793 _refine_diff_density_max 0.202 _refine_diff_density_min -0.342 _refine_diff_density_rms 0.030