Methyl and t-butyl group rotation in a molecular solid: (1)H NMR spin-lattice relaxation and X-ray diffraction.
Beckmann, Peter A.; Moore, Curtis E.; Rheingold, Arnold L.; Physical chemistry chemical physics : PCCP 18 (2016) 1720–1726; doi:10.1039/c5cp04994f

data_7223426
_publ_section_title
;
 Methyl and t-butyl group rotation in a molecular solid: (1)H NMR
 spin-lattice relaxation and X-ray diffraction.
;
_journal_issue                   3
_journal_name_full               'Physical chemistry chemical physics : PCCP'
_journal_page_first              1720
_journal_page_last               1726
_journal_paper_doi               10.1039/c5cp04994f
_journal_volume                  18
_journal_year                    2016
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C16 H21 Br O Si'
_chemical_formula_sum            'C16 H21 Br O Si'
_chemical_formula_weight         337.33
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_audit_creation_date             2015-08-24
_audit_creation_method
;
Olex2 1.2
(compiled 2015.01.26 svn.r3150 for OlexSys, GUI svn.r4998)
;
_audit_update_record
;
2015-08-24 deposited with the CCDC.
2015-12-07 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 101.3670(10)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   7.0513(3)
_cell_length_b                   7.6501(2)
_cell_length_c                   15.5178(7)
_cell_measurement_reflns_used    3641
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      25.42
_cell_measurement_theta_min      2.68
_cell_volume                     820.66(6)
_computing_molecular_graphics    'Olex2 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'XL (Sheldrick, 2008)'
_computing_structure_solution    'ShelXS (Sheldrick, 2008)'
_diffrn_ambient_temperature      100.15
_diffrn_detector                 'Bruker APEX-II CCD'
_diffrn_detector_area_resol_mean 7.9
_diffrn_detector_type            'CCD Area Detector'
_diffrn_measured_fraction_theta_full 0.984
_diffrn_measured_fraction_theta_max 0.982
_diffrn_measurement_device       'Kappa Four-Circle Diffractometer'
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0176
_diffrn_reflns_av_unetI/netI     0.0445
_diffrn_reflns_Laue_measured_fraction_full 0.984
_diffrn_reflns_Laue_measured_fraction_max 0.982
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            4924
_diffrn_reflns_point_group_measured_fraction_full 0.907
_diffrn_reflns_point_group_measured_fraction_max 0.901
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.442
_diffrn_reflns_theta_min         2.678
_diffrn_source_type              'Bruker TXS'
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    2.569
_exptl_absorpt_correction_T_max  0.637
_exptl_absorpt_correction_T_min  0.566
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.365
_exptl_crystal_description       block
_exptl_crystal_F_000             348
_exptl_crystal_size_max          0.34
_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.1
_refine_diff_density_max         0.248
_refine_diff_density_min         -0.217
_refine_diff_density_rms         0.039
_refine_ls_abs_structure_details
;
 Flack x determined using 997 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.029(6)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.874
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     177
_refine_ls_number_reflns         2742
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.874
_refine_ls_R_factor_all          0.0206
_refine_ls_R_factor_gt           0.0186
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details     'w=1/[\s^2^(Fo^2^)] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0424
_refine_ls_wR_factor_ref         0.0430
_reflns_Friedel_coverage         0.699
_reflns_Friedel_fraction_full    0.816
_reflns_Friedel_fraction_max     0.806
_reflns_number_gt                2567
_reflns_number_total             2742
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c5cp04994f1.cif
_cod_data_source_block           beck28
_cod_depositor_comments
;
The following automatic conversions were performed:

'_diffrn_radiation_probe' value 'X-ray' changed to 'x-ray' according
to
/usr/data/users/saulius/crontab/automatic-downloads/rss-feeds/RSC/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 4268 2015-11-12 08:31:59Z antanas 

 Adding full bibliography for 7223426.cif.
;
_cod_database_code               7223426
_shelx_estimated_absorpt_t_max   0.783
_shelx_estimated_absorpt_t_min   0.475
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Aromatic/amide H refined with riding coordinates:
 C1(H1), C3(H3), C4(H4), C5(H5), C7(H7), C8(H8)
2.b Idealised Me refined as rotating group:
 C11(H11A,H11B,H11C), C12(H12A,H12B,H12C), C14(H14A,H14B,H14C), C15(H15A,H15B,
 H15C), C16(H16A,H16B,H16C)
;
_shelx_res_checksum              45288
_shelx_hkl_checksum              46637
_shelx_shelxl_version_number     2014/7
_olex2_submission_special_instructions 'No special instructions were received'