2,2,6,6-Tetrakis(biphenyl-2-yl)-4,4,8,8-tetramethylcyclotetrasiloxane
Couzijn, Erik P. A.; Lutz, Martin; Spek, Anthony L.; Lammertsma, Koop; Acta Crystallographica Section E 65 (2009) o2182–o2183; doi:10.1107/S1600536809031961

data_2223216
_publ_section_title
;
 2,2,6,6-Tetrakis(biphenyl-2-yl)-4,4,8,8-tetramethylcyclotetrasiloxane
;
_journal_coeditor_code           VM2002
_journal_issue                   9
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o2182
_journal_page_last               o2183
_journal_paper_doi               10.1107/S1600536809031961
_journal_volume                  65
_journal_year                    2009
_chemical_formula_iupac          'C52 H48 O4 Si4'
_chemical_formula_moiety         'C52 H48 O4 Si4'
_chemical_formula_sum            'C52 H48 O4 Si4'
_chemical_formula_weight         849.26
_chemical_name_systematic
;
2,2,6,6-Tetrakis(biphenyl-2-yl)-4,4,8,8-tetramethylcyclotetrasiloxane
;
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   17.3418(2)
_cell_length_b                   14.6488(2)
_cell_length_c                   17.9584(2)
_cell_measurement_reflns_used    88729
_cell_measurement_temperature    110(2)
_cell_measurement_theta_max      25.68
_cell_measurement_theta_min      1.02
_cell_volume                     4562.09(10)
_computing_cell_refinement       'HKL2000 (Otwinowski & Minor, 1997)'
_computing_data_collection       'COLLECT (Nonius, 1999)'
_computing_data_reduction
;
HKL2000 (Otwinowski & Minor, 1997) and
SORTAV (Blessing, 1997)
;
_computing_molecular_graphics    'PLATON (Spek, 2009)'
_computing_publication_material  'manual editing of SHELXL output'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SIR97 (Altomare <i>et al.</i>,  1999)'
_diffrn_ambient_temperature      110(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Nonius KappaCCD'
_diffrn_measurement_method       '\f and \w'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0807
_diffrn_reflns_av_sigmaI/netI    0.0339
_diffrn_reflns_limit_h_max       21
_diffrn_reflns_limit_h_min       -21
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            68467
_diffrn_reflns_theta_full        25.68
_diffrn_reflns_theta_max         25.68
_diffrn_reflns_theta_min         2.14
_exptl_absorpt_coefficient_mu    0.175
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.236
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             1792
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.12
_exptl_crystal_size_min          0.03
_refine_diff_density_max         0.261
_refine_diff_density_min         -0.326
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.067
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     273
_refine_ls_number_reflns         4317
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.067
_refine_ls_R_factor_all          0.0579
_refine_ls_R_factor_gt           0.0356
_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^)+(0.0428P)^2^+1.7858P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0868
_refine_ls_wR_factor_ref         0.0966
_reflns_number_gt                3247
_reflns_number_total             4317
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            vm2002.cif
_cod_data_source_block           I
_cod_database_code               2223216
_cod_database_fobs_code          2223216