Crystal Engineering of Hand-Twisted Helical Crystals.
Saha, Subhankar; Desiraju, Gautam R.; Journal of the American Chemical Society 139 (2017) 1975–1983; doi:10.1021/jacs.6b11835

data_4125697
_publ_section_title
;
 Crystal Engineering of Hand-Twisted Helical Crystals.
;
_journal_issue                   5
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              1975
_journal_page_last               1983
_journal_paper_doi               10.1021/jacs.6b11835
_journal_volume                  139
_journal_year                    2017
_chemical_formula_sum            'C6 H4 Br2'
_chemical_formula_weight         235.89
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_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                 97.21(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   4.035(6)
_cell_length_b                   5.763(8)
_cell_length_c                   14.35(2)
_cell_measurement_reflns_used    1222
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      33.7
_cell_measurement_theta_min      2.9
_cell_volume                     331.1(8)
_computing_cell_refinement
;
CrystalClear-SM Expert 2.0 rc14 (Rigaku, 2009)
;
_computing_data_collection
;
CrystalClear-SM Expert 2.0 rc14 (Rigaku, 2009)
;
_computing_data_reduction
;
CrystalClear-SM Expert 2.0 rc14 (Rigaku, 2009)
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXL-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      150(2)
_diffrn_detector_area_resol_mean 13.6612
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device
;
XtaLABmini: Fixed Chi 2 circle
;
_diffrn_measurement_device_type
;
Rigaku Mercury375R (2x2 bin mode)
;
_diffrn_measurement_method       'profile data from \w-scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.2834
_diffrn_reflns_av_sigmaI/netI    0.1692
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_h_min       -4
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            2934
_diffrn_reflns_theta_full        25.98
_diffrn_reflns_theta_max         25.98
_diffrn_reflns_theta_min         2.86
_exptl_absorpt_coefficient_mu    12.125
_exptl_absorpt_correction_T_max  0.3769
_exptl_absorpt_correction_T_min  0.3489
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Jacobson, R. (1998) Private communication'
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    2.367
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Block
_exptl_crystal_F_000             220
_exptl_crystal_size_max          0.11
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.10
_refine_diff_density_max         1.104
_refine_diff_density_min         -1.822
_refine_diff_density_rms         0.324
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.171
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     37
_refine_ls_number_reflns         644
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.171
_refine_ls_R_factor_all          0.0650
_refine_ls_R_factor_gt           0.0629
_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^)+(0.0733P)^2^+0.9248P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1856
_refine_ls_wR_factor_ref         0.1884
_reflns_number_gt                606
_reflns_number_total             644
_reflns_threshold_expression     >2\s(I)
_cod_data_source_file            ja6b11835_si_004.cif
_cod_data_source_block           1
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to
/home/data/users/saulius/crontab/automatic-downloads/current/ACS/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 4973 2017-02-22 13:04:09Z antanas 
;
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               4125697