Cyclobutadiene Dianions Consisting of Heavier Group 14 Elements: Synthesis and Characterization
Vladimir Ya. Lee; Kazunori Takanashi; Tadahiro Matsuno; Masaaki Ichinohe; Akira Sekiguchi; Journal of the American Chemical Society 126 (2004) 4758–4759; doi:10.1021/ja030662z

data_4112437
_publ_section_title
;
 Cyclobutadiene Dianions Consisting of Heavier Group 14 Elements:
 Synthesis and Characterization
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              4758
_journal_page_last               4759
_journal_paper_doi               10.1021/ja030662z
_journal_volume                  126
_journal_year                    2004
_chemical_formula_sum            'C52 H116 K2 O4 Si8'
_chemical_formula_weight         1108.37
_chemical_name_systematic
; 
 Bis[bis(tetrahydrofuran)potassium(I)] tetrakis(di-tert-butylmethylsilyl)-
 tetrasilacyclobutadiene dianion
;
_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                89.659(3)
_cell_angle_beta                 88.870(2)
_cell_angle_gamma                61.283(3)
_cell_formula_units_Z            2
_cell_length_a                   13.0830(7)
_cell_length_b                   13.3180(4)
_cell_length_c                   22.2070(10)
_cell_measurement_reflns_used    31807
_cell_measurement_temperature    120.0(1)
_cell_measurement_theta_max      28.01
_cell_measurement_theta_min      2.53
_cell_volume                     3392.7(3)
_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    SIR92
_diffrn_ambient_temperature      120.0(1)
_diffrn_measured_fraction_theta_full 0.872
_diffrn_measured_fraction_theta_max 0.872
_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  0.0280
_diffrn_reflns_av_sigmaI/netI    0.0369
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            31807
_diffrn_reflns_theta_full        28.01
_diffrn_reflns_theta_max         28.01
_diffrn_reflns_theta_min         2.53
_exptl_absorpt_coefficient_mu    0.317
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            'Dark green'
_exptl_crystal_density_diffrn    1.085
_exptl_crystal_description       Cube
_exptl_crystal_F_000             1220
_exptl_crystal_size_max          0.3
_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.25
_refine_diff_density_max         0.841
_refine_diff_density_min         -0.446
_refine_diff_density_rms         0.072
_refine_ls_extinction_coef       0.0190(12)
_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   1.018
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     596
_refine_ls_number_reflns         14318
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.018
_refine_ls_R_factor_all          0.0607
_refine_ls_R_factor_gt           0.0532
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0960P)^2^+1.4696P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1472
_refine_ls_wR_factor_ref         0.1535
_reflns_number_gt                12184
_reflns_number_total             14318
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja030662z_s.cif
_cod_data_source_block           shelxl
_cod_original_sg_symbol_H-M      'P -1 '
_cod_database_code               4112437