The First Halogen-Substituted Cyclotrigermenes: A Unique Halogen Walk over the Three-Membered Ring Skeleton and Facial Stereoselectivity in the Diels-Alder Reaction
Akira Sekiguchi; Yutaka Ishida; Norihisa Fukaya; Masaaki Ichinohe; Nozomi Takagi; Shigeru Nagase; Journal of the American Chemical Society 124 (2002) 1158–1159; doi:10.1021/ja012216m

data_4114617
_publ_section_title
;
 The First Halogen-Substituted Cyclotrigermenes: A Unique Halogen Walk
 over the Three-Membered Ring Skeleton and Facial Stereoselectivity in the
 Diels-Alder Reaction
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              1158
_journal_page_last               1159
_journal_paper_doi               10.1021/ja012216m
_journal_volume                  124
_journal_year                    2002
_chemical_formula_sum            'C36 H81 Br Ge3 Si3'
_chemical_formula_weight         895.96
_chemical_name_systematic
; 
 3-Bromo-1,2,3-tris(tri-t-butylsilyl)cyclotrigermene 
;
_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                74.530(5)
_cell_angle_beta                 82.005(6)
_cell_angle_gamma                60.497(5)
_cell_formula_units_Z            2
_cell_length_a                   13.4860(10)
_cell_length_b                   13.6600(16)
_cell_length_c                   14.9860(19)
_cell_measurement_reflns_used    21138
_cell_measurement_temperature    120
_cell_measurement_theta_max      27.96
_cell_measurement_theta_min      2.82
_cell_volume                     2315.6(5)
_computing_cell_refinement       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
_diffrn_measured_fraction_theta_full 0.898
_diffrn_measured_fraction_theta_max 0.898
_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  0.0790
_diffrn_reflns_av_sigmaI/netI    0.1071
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            21138
_diffrn_reflns_theta_full        27.96
_diffrn_reflns_theta_max         27.96
_diffrn_reflns_theta_min         2.82
_exptl_absorpt_coefficient_mu    2.896
_exptl_crystal_colour            Red
_exptl_crystal_density_diffrn    1.285
_exptl_crystal_description       'cubic '
_exptl_crystal_F_000             940
_exptl_crystal_size_max          0.2
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.1
_refine_diff_density_max         1.145
_refine_diff_density_min         -0.917
_refine_diff_density_rms         0.129
_refine_ls_extinction_coef       0.0023(4)
_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   1.020
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     389
_refine_ls_number_reflns         9992
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.020
_refine_ls_R_factor_all          0.1139
_refine_ls_R_factor_gt           0.0607
_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^)+(0.0420P)^2^+3.6523P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1168
_refine_ls_wR_factor_ref         0.1386
_reflns_number_gt                6369
_reflns_number_total             9992
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja012216m_2.cif
_cod_data_source_block           shelxl
_cod_original_cell_volume        2315.6(4)
_cod_database_code               4114617