Supplementary Material (ESI) for Dalton Transactions This journal is © The Royal Society of Chemistry 2005 data_global _journal_name_full 'Dalton Trans.' _journal_coden_Cambridge 0222 _publ_contact_author_name 'Prof David Rankin' _publ_contact_author_address ; Department of Chemistry University of Edinburgh West Mains Road Edinburgh EH9 3JJ UNITED KINGDOM ; _publ_contact_author_email D.W.H.RANKIN@ED.AC.UK _publ_section_title ; The experimental gas-phase structures of 1,3,5-trisilylbenzene and hexasilylbenzene and the theoretical structures of all benzenes with three or more silyl substituents ; loop_ _publ_author_name 'D. Rankin' 'Blair F. Johnston' 'Norbert Mitzel' 'Heather E. Robertson' 'Christoph Rudinger' S.H data_sihmes _database_code_depnum_ccdc_archive 'CCDC 266041' _audit_creation_method SHELXL-97 _chemical_name_systematic ; 1,3,5-Trisilylbenzene ; _chemical_name_common 1,3,5-Trisilylbenzene _chemical_melting_point ? _chemical_formula_moiety ? _chemical_formula_sum 'C6 H12 Si3' _chemical_formula_weight 168.43 loop_ _atom_type_symbol _atom_type_description _atom_type_scat_dispersion_real _atom_type_scat_dispersion_imag _atom_type_scat_source C C 0.0033 0.0016 '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' Si Si 0.0817 0.0704 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' _symmetry_cell_setting Tetragonal _symmetry_space_group_name_H-M P42/mbc loop_ _symmetry_equiv_pos_as_xyz 'x, y, z' '-x, -y, z' '-y, x, z+1/2' 'y, -x, z+1/2' '-x+1/2, y+1/2, -z' 'x+1/2, -y+1/2, -z' 'y+1/2, x+1/2, -z+1/2' '-y+1/2, -x+1/2, -z+1/2' '-x, -y, -z' 'x, y, -z' 'y, -x, -z-1/2' '-y, x, -z-1/2' 'x-1/2, -y-1/2, z' '-x-1/2, y-1/2, z' '-y-1/2, -x-1/2, z-1/2' 'y-1/2, x-1/2, z-1/2' _cell_length_a 11.3393(6) _cell_length_b 11.3393(6) _cell_length_c 16.3909(14) _cell_angle_alpha 90.00 _cell_angle_beta 90.00 _cell_angle_gamma 90.00 _cell_volume 2107.5(2) _cell_formula_units_Z 8 _cell_measurement_temperature 140(2) _cell_measurement_reflns_used 100 _cell_measurement_theta_min 17 _cell_measurement_theta_max 22 _exptl_crystal_description Cylinder _exptl_crystal_colour Colourless _exptl_crystal_size_max 1.0 _exptl_crystal_size_mid 0.3 _exptl_crystal_size_min 0.3 _exptl_crystal_density_meas ? _exptl_crystal_density_diffrn 1.062 _exptl_crystal_density_method 'not measured' _exptl_crystal_F_000 720 _exptl_absorpt_coefficient_mu 0.382 _exptl_absorpt_correction_type none _exptl_absorpt_correction_T_min ? _exptl_absorpt_correction_T_max ? _exptl_absorpt_process_details ? _exptl_special_details ; Crystal grown in siutu from a sample sealed into a capillary ; _diffrn_ambient_temperature 140(2) _diffrn_radiation_wavelength 0.71073 _diffrn_radiation_type MoK\a _diffrn_radiation_source 'fine-focus sealed tube' _diffrn_radiation_monochromator graphite _diffrn_measurement_device_type 'Nonius Turbo CAD 4' _diffrn_measurement_method 'Omega scans' _diffrn_detector_area_resol_mean ? _diffrn_standards_number 3 _diffrn_standards_interval_count ? _diffrn_standards_interval_time 60 _diffrn_standards_decay_% None _diffrn_reflns_number 1855 _diffrn_reflns_av_R_equivalents 0.0563 _diffrn_reflns_av_sigmaI/netI 0.0565 _diffrn_reflns_limit_h_min 0 _diffrn_reflns_limit_h_max 13 _diffrn_reflns_limit_k_min 0 _diffrn_reflns_limit_k_max 13 _diffrn_reflns_limit_l_min 0 _diffrn_reflns_limit_l_max 19 _diffrn_reflns_theta_min 2.54 _diffrn_reflns_theta_max 25.01 _reflns_number_total 964 _reflns_number_gt 545 _reflns_threshold_expression >2sigma(I) _computing_data_collection 'CAD4 software' _computing_cell_refinement 'CAD4 software' _computing_data_reduction CADSHEL _computing_structure_solution 'SHELXS-97 (Sheldrick, 1990)' _computing_structure_refinement 'SHELXL-97 (Sheldrick, 1997)' _computing_molecular_graphics 'SHELXTL 5.01' _computing_publication_material 'SHELXTL 5.01' _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 _refine_ls_weighting_details 'calc w=1/[\s^2^(Fo^2^)+(0.0940P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3' _atom_sites_solution_primary direct _atom_sites_solution_secondary difmap _atom_sites_solution_hydrogens geom _refine_ls_hydrogen_treatment mixed _refine_ls_extinction_method SHELXL _refine_ls_extinction_coef 0.0020(10) _refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^ _refine_ls_number_reflns 964 _refine_ls_number_parameters 58 _refine_ls_number_restraints 15 _refine_ls_R_factor_all 0.1151 _refine_ls_R_factor_gt 0.0560 _refine_ls_wR_factor_ref 0.1743 _refine_ls_wR_factor_gt 0.1434 _refine_ls_goodness_of_fit_ref 0.992 _refine_ls_restrained_S_all 0.983 _refine_ls_shift/su_max 0.000 _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_symmetry_multiplicity _atom_site_calc_flag _atom_site_refinement_flags _atom_site_disorder_assembly _atom_site_disorder_group Si1 Si 1.05242(15) 0.27439(16) 0.5000 0.0675(8) Uani 1 2 d SD . . H11 H 1.134(2) 0.247(2) 0.554(2) 0.101 Uiso 0.50 1 calc PRD . . H12 H 1.0053(9) 0.3772(15) 0.519(3) 0.101 Uiso 0.50 1 calc PRD . . H13 H 1.100(3) 0.281(3) 0.4268(13) 0.101 Uiso 0.50 1 calc PRD . . C1 C 0.9355(5) 0.1587(5) 0.5000 0.0453(15) Uani 1 2 d S . . C2 C 0.8898(3) 0.1142(3) 0.5726(3) 0.0419(10) Uani 1 1 d . . . H2 H 0.916(3) 0.142(3) 0.623(3) 0.060(14) Uiso 1 1 d . . . Si3 Si 0.74139(14) -0.03040(13) 0.67167(7) 0.0640(6) Uani 1 1 d D . . H31 H 0.6886(17) 0.0554(12) 0.7121(8) 0.096 Uiso 1 1 calc RD . . H32 H 0.8276(11) -0.0741(17) 0.7165(8) 0.064 Uiso 1 1 calc RD . . H33 H 0.6643(17) -0.1144(17) 0.6552(2) 0.064 Uiso 1 1 calc RD . . C3 C 0.8030(3) 0.0287(3) 0.5746(2) 0.0375(10) Uani 1 1 d . . . C4 C 0.7605(5) -0.0133(5) 0.5000 0.0342(12) Uani 1 2 d S . . H4 H 0.699(4) -0.076(5) 0.5000 0.037(15) Uiso 1 2 d S . . 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 Si1 0.0296(9) 0.0345(10) 0.138(2) 0.000 0.000 -0.0042(8) C1 0.030(3) 0.033(3) 0.073(4) 0.000 0.000 0.006(3) C2 0.034(2) 0.038(2) 0.053(3) -0.009(2) -0.013(2) 0.0044(18) Si3 0.0747(10) 0.0765(10) 0.0407(8) 0.0056(7) 0.0086(8) -0.0011(8) C3 0.032(2) 0.035(2) 0.045(2) -0.0018(19) -0.0018(19) 0.0046(16) C4 0.028(3) 0.030(3) 0.044(3) 0.000 0.000 0.001(2) _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 Si1 C1 1.865(6) . ? Si1 H11 1.3202 . ? Si1 H12 1.3202 . ? Si1 H13 1.3202 . ? C1 C2 1.393(5) 10_556 ? C1 C2 1.393(5) . ? C2 C3 1.382(5) . ? C2 H2 0.94(4) . ? Si3 C3 1.863(4) . ? Si3 H31 1.3202 . ? Si3 H32 1.3202 . ? Si3 H33 1.3202 . ? C3 C4 1.398(5) . ? C4 C3 1.398(5) 10_556 ? C4 H4 1.00(5) . ? 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 C1 Si1 H11 109.5 . . ? C1 Si1 H12 109.5 . . ? H11 Si1 H12 109.5 . . ? C1 Si1 H13 109.5 . . ? H11 Si1 H13 109.5 . . ? H12 Si1 H13 109.5 . . ? C2 C1 C2 117.4(5) 10_556 . ? C2 C1 Si1 121.3(3) 10_556 . ? C2 C1 Si1 121.3(3) . . ? C3 C2 C1 122.7(4) . . ? C3 C2 H2 116(3) . . ? C1 C2 H2 121(3) . . ? C3 Si3 H31 109.5 . . ? C3 Si3 H32 109.5 . . ? H31 Si3 H32 109.5 . . ? C3 Si3 H33 109.5 . . ? H31 Si3 H33 109.5 . . ? H32 Si3 H33 109.5 . . ? C2 C3 C4 117.6(4) . . ? C2 C3 Si3 122.7(3) . . ? C4 C3 Si3 119.7(3) . . ? C3 C4 C3 122.0(5) . 10_556 ? C3 C4 H4 119.0(3) . . ? C3 C4 H4 119.0(3) 10_556 . ? 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 C2 C1 C2 C3 0.4(8) 10_556 . . . ? Si1 C1 C2 C3 179.9(3) . . . . ? C1 C2 C3 C4 -0.2(6) . . . . ? C1 C2 C3 Si3 -179.7(4) . . . . ? C2 C3 C4 C3 -0.1(7) . . . 10_556 ? Si3 C3 C4 C3 179.5(3) . . . 10_556 ? _diffrn_measured_fraction_theta_max 0.993 _diffrn_reflns_theta_full 25.01 _diffrn_measured_fraction_theta_full 0.993 _refine_diff_density_max 0.276 _refine_diff_density_min -0.297 _refine_diff_density_rms 0.059