Interplay of EnE'3-nC Valence Isomers (E, E' = Si, Ge): Bicyclo[1.1.0]butanes with Very Short Bridging Bonds and Their Isomerization to Alkyl-Substituted Cyclopropenes
Vladimir Ya. Lee; Hiroyuki Yasuda; Akira Sekiguchi; Journal of the American Chemical Society 129 (2007) 2436–2437; doi:10.1021/ja068229n

data_4109147
_publ_section_title
;
 Interplay of EnE'3-nC Valence Isomers (E, E' = Si, Ge):
 Bicyclo[1.1.0]butanes with Very Short Bridging Bonds and Their
 Isomerization to Alkyl-Substituted Cyclopropenes
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              2436
_journal_page_last               2437
_journal_paper_doi               10.1021/ja068229n
_journal_volume                  129
_journal_year                    2007
_chemical_formula_sum            'C37 H86 Si7'
_chemical_formula_weight         727.69
_chemical_name_systematic
; 
 Si3C-bicyclo[1.1.0]butane 
;
_space_group_IT_number           7
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P -2yc'
_symmetry_space_group_name_H-M   'P 1 c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 91.642(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.7370(2)
_cell_length_b                   17.8260(6)
_cell_length_c                   22.7190(6)
_cell_measurement_reflns_used    42685
_cell_measurement_temperature    120
_cell_measurement_theta_max      27.96
_cell_measurement_theta_min      2.13
_cell_volume                     4751.4(2)
_computing_cell_refinement       'HKL scalepack'
_computing_data_collection       'MacScience Xpress'
_computing_data_reduction        Denzo
_computing_molecular_graphics    ORTEP
_computing_publication_material  CIFTAB
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      120
_diffrn_measured_fraction_theta_full 0.921
_diffrn_measured_fraction_theta_max 0.921
_diffrn_measurement_device_type  'MacScience DIP2030 Image plate'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71070
_diffrn_reflns_av_R_equivalents  0.042
_diffrn_reflns_av_sigmaI/netI    0.0203
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       23
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            10540
_diffrn_reflns_theta_full        27.96
_diffrn_reflns_theta_max         27.96
_diffrn_reflns_theta_min         2.13
_exptl_absorpt_coefficient_mu    0.223
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.017
_exptl_crystal_description       plates
_exptl_crystal_F_000             1624
_exptl_crystal_size_max          0.50
_exptl_crystal_size_mid          0.50
_exptl_crystal_size_min          0.40
_refine_diff_density_max         0.447
_refine_diff_density_min         -0.321
_refine_diff_density_rms         0.069
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.16(7)
_refine_ls_extinction_coef       0.0167(9)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.083
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     794
_refine_ls_number_reflns         10540
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.083
_refine_ls_R_factor_all          0.0381
_refine_ls_R_factor_gt           0.0370
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0707P)^2^+0.8685P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1012
_refine_ls_wR_factor_ref         0.1024
_reflns_number_gt                10212
_reflns_number_total             10540
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja068229nsi20061117_010301.cif
_cod_data_source_block           shelxl
_cod_original_sg_symbol_H-M      'P c '
_cod_database_code               4109147