Thermal motion of <i>tert</i>-butyl groups III. <i>tert</i>-Butyl substituents in aromatic hydrocarbons, the view from the bottom of the well
Frey, Joseph; Khan, Saeed I.; Knobler, Carolyn B.; Lightner, David A.; Maverick, Emily F.; Phillips, Daniel J.; Rappoport, Zvi; Trueblood, Kenneth N.; Acta Crystallographica Section B 66 (2010) 622–638; doi:10.1107/S0108768110040024

data_2104824
_publ_section_title
;
 Thermal motion of <i>tert</i>-butyl groups III. <i>tert</i>-Butyl
 substituents in aromatic hydrocarbons, the view from the bottom of the
 well
;
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              622
_journal_page_last               638
_journal_paper_doi               10.1107/S0108768110040024
_journal_volume                  66
_journal_year                    2010
_chemical_formula_moiety         'C34 H31.98 I0.02'
_chemical_formula_sum            'C34 H31.98 I0.02'
_chemical_formula_weight         443.11
_chemical_name_systematic
;
  2,15-di-(tert-butyl)-hexahelicene
;
_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   geom
_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            8
_cell_length_a                   9.8836(3)
_cell_length_b                   16.7096(5)
_cell_length_c                   30.5719(10)
_cell_measurement_reflns_used    8561
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      63.64
_cell_measurement_theta_min      2.89
_cell_volume                     5049.0(3)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      298(2)
_diffrn_measured_fraction_theta_full 0.980
_diffrn_measured_fraction_theta_max 0.980
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0315
_diffrn_reflns_av_sigmaI/netI    0.0232
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       34
_diffrn_reflns_limit_l_min       -30
_diffrn_reflns_number            24764
_diffrn_reflns_theta_full        64.47
_diffrn_reflns_theta_max         64.47
_diffrn_reflns_theta_min         2.89
_exptl_absorpt_coefficient_mu    0.680
_exptl_absorpt_correction_T_max  0.990
_exptl_absorpt_correction_T_min  0.690
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Bruker)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.166
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       rod
_exptl_crystal_F_000             1896
_exptl_crystal_size_max          0.60
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.164
_refine_diff_density_min         -0.185
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.052
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     331
_refine_ls_number_reflns         4162
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.052
_refine_ls_R_factor_all          0.0636
_refine_ls_R_factor_gt           0.0494
_refine_ls_shift/su_max          0.008
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0711P)^2^+1.0652P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1326
_refine_ls_wR_factor_ref         0.1430
_reflns_number_gt                3221
_reflns_number_total             4162
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            bk5096.cif
_cod_data_source_block           Vd
_cod_database_code               2104824