Base-Free Molybdenum and Tungsten Bicyclic Silylene Complexes Stabilized by a Homoaromatic Contribution
Kazunori Takanashi; Vladimir Ya. Lee; Taka Yokoyama; Akira Sekiguchi; Journal of the American Chemical Society 131 (2009) 916–917; doi:10.1021/ja8088313

data_4103837
_publ_section_title
;
 Base-Free Molybdenum and Tungsten Bicyclic Silylene Complexes Stabilized
 by a Homoaromatic Contribution
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              916
_journal_page_last               917
_journal_paper_doi               10.1021/ja8088313
_journal_volume                  131
_journal_year                    2009
_chemical_formula_sum            'C52 H108 Si8 W'
_chemical_formula_weight         1141.95
_chemical_name_systematic
; 
Cp2WSi4(SiMetBu2) 
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/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                 106.100(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.7460(5)
_cell_length_b                   13.3610(3)
_cell_length_c                   41.3200(13)
_cell_measurement_reflns_used    59493
_cell_measurement_temperature    150.0(1)
_cell_measurement_theta_max      28.0
_cell_measurement_theta_min      2.17
_cell_volume                     6230.4(4)
_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      150.0(1)
_diffrn_measured_fraction_theta_full 0.955
_diffrn_measured_fraction_theta_max 0.955
_diffrn_measurement_device       '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  0.0000
_diffrn_reflns_av_sigmaI/netI    0.0586
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       0
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       51
_diffrn_reflns_limit_l_min       -54
_diffrn_reflns_number            14398
_diffrn_reflns_theta_full        28.00
_diffrn_reflns_theta_max         28.00
_diffrn_reflns_theta_min         2.17
_exptl_absorpt_coefficient_mu    2.038
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    1.217
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             2424
_exptl_crystal_size_max          0.2
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.721
_refine_diff_density_min         -2.319
_refine_diff_density_rms         0.138
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.038
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     550
_refine_ls_number_reflns         14398
_refine_ls_number_restraints     9
_refine_ls_restrained_S_all      1.042
_refine_ls_R_factor_all          0.0786
_refine_ls_R_factor_gt           0.0552
_refine_ls_shift/su_max          0.004
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0774P)^2^+3.6285P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1300
_refine_ls_wR_factor_ref         0.1425
_reflns_number_gt                10761
_reflns_number_total             14398
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja8088313_si_001.cif
_cod_data_source_block           shelxl
_cod_original_sg_symbol_H-M      'P 21/c '
_cod_database_code               4103837