Access to a Stable Si2N2 Four-Membered Ring with Non-Kekulé Singlet Biradical Character from a Disilyne
Katsuhiko Takeuchi; Masaaki Ichinohe; Akira Sekiguchi; Journal of the American Chemical Society 133 (2011) 12478–12481; doi:10.1021/ja2059846

data_4106593
_publ_section_title
;
 Access to a Stable Si2N2 Four-Membered Ring with Non-Kekul\'e Singlet
 Biradical Character from a Disilyne
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              12478
_journal_page_last               12481
_journal_paper_doi               10.1021/ja2059846
_journal_volume                  133
_journal_year                    2011
_chemical_formula_sum            'C50 H108 Cl2 N2 Si12'
_chemical_formula_weight         1145.36
_chemical_name_systematic
; 
 trans-2,4-Bis{bis[bis(trimethylsilyl)methyl]isopropylsilyl}-2,4-dichloro- 
 1,3-bis(3,5-dimethylphenyl)-1,3-diaza-2,4-disilacyclobutane 
;
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                101.0170(10)
_cell_angle_beta                 106.5390(10)
_cell_angle_gamma                109.2130(10)
_cell_formula_units_Z            1
_cell_length_a                   9.9490(5)
_cell_length_b                   13.7022(7)
_cell_length_c                   14.5004(7)
_cell_measurement_reflns_used    9960
_cell_measurement_temperature    150.0(1)
_cell_measurement_theta_max      28.10
_cell_measurement_theta_min      2.25
_cell_volume                     1698.56(15)
_computing_cell_refinement       'APEX2 (Bruker AXS, 2006)'
_computing_data_collection       'APEX2 (Bruker AXS, 2006)'
_computing_data_reduction        'SAINT (Bruker AXS, 2004)'
_computing_molecular_graphics    'XSHEL (Bruker AXS,2002)'
_computing_publication_material  'XCIF (Bruker AXS, 2001)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      150.0(1)
_diffrn_detector_area_resol_mean 8.333
_diffrn_measured_fraction_theta_full 0.977
_diffrn_measured_fraction_theta_max 0.977
_diffrn_measurement_device_type  'Bruker APEXII CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0190
_diffrn_reflns_av_sigmaI/netI    0.0229
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            19316
_diffrn_reflns_theta_full        27.48
_diffrn_reflns_theta_max         27.48
_diffrn_reflns_theta_min         1.54
_exptl_absorpt_coefficient_mu    0.339
_exptl_absorpt_correction_T_max  0.9372
_exptl_absorpt_correction_T_min  0.8871
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details
; 
SADABS Sheldrick 1996 
;
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.120
_exptl_crystal_description       Prism
_exptl_crystal_F_000             624
_exptl_crystal_size_max          0.36
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.19
_refine_diff_density_max         0.410
_refine_diff_density_min         -0.383
_refine_diff_density_rms         0.053
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.031
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     298
_refine_ls_number_reflns         7592
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.031
_refine_ls_R_factor_all          0.0402
_refine_ls_R_factor_gt           0.0348
_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^)+(0.0555P)^2^+0.9351P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1006
_refine_ls_wR_factor_ref         0.1055
_reflns_number_gt                6669
_reflns_number_total             7592
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja2059846_si_002.cif
_cod_data_source_block           si2n2cl2_0m
_cod_original_cell_volume        1698.55(15)
_cod_original_sg_symbol_H-M      'P -1 '
_cod_database_code               4106593