Internal dynamics in helical molecules studied by X-ray diffraction, NMR spectroscopy and DFT calculations.
Dračínský, Martin; Storch, Jan; Církva, Vladimír; Císařová, Ivana; Sýkora, Jan; Physical chemistry chemical physics : PCCP 19 (2017) 2900–2907; doi:10.1039/c6cp07552e

data_7227336
_publ_section_title
;
 Internal dynamics in helical molecules studied by X-ray diffraction, NMR
 spectroscopy and DFT calculations.
;
_journal_issue                   4
_journal_name_full               'Physical chemistry chemical physics : PCCP'
_journal_page_first              2900
_journal_page_last               2907
_journal_paper_doi               10.1039/c6cp07552e
_journal_volume                  19
_journal_year                    2017
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C26 H16'
_chemical_formula_sum            'C26 H16'
_chemical_formula_weight         328.41
_chemical_name_systematic        '[6]helicene'
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_audit_update_record
;
2016-11-03 deposited with the CCDC.
2017-01-03 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.3058(2)
_cell_length_b                   12.9470(5)
_cell_length_c                   17.4452(6)
_cell_measurement_reflns_used    8265
_cell_measurement_temperature    100
_cell_measurement_theta_max      28
_cell_measurement_theta_min      2
_cell_volume                     1650.11(10)
_computing_cell_refinement       'DENZO/SCALEPACK (Otwinowski & Minor, 1997)'
_computing_data_collection       'COLLECT (Nonius, 2001).'
_computing_data_reduction        'DENZO/SCALEPACK (Otwinowski & Minor, 1997)'
_computing_molecular_graphics    'CAMERON (Watkin et al., 1996)'
_computing_publication_material  'CRYSTALS (Betteridge et al., 2003)'
_computing_structure_refinement  'CRYSTALS (Betteridge et al., 2003)'
_computing_structure_solution    'SHELXS 86 (Sheldrick, 1986)'
_diffrn_ambient_temperature      100
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device       Area
_diffrn_measurement_device_type  'Nonius KappaCCD'
_diffrn_measurement_method       '\f & \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.018
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            8265
_diffrn_reflns_theta_full        27.498
_diffrn_reflns_theta_max         27.498
_diffrn_reflns_theta_min         1.959
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.075
_exptl_absorpt_correction_T_max  0.98
_exptl_absorpt_correction_T_min  0.95
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'DENZO/SCALEPACK (Otwinowski & Minor, 1997)'
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.322
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             688
_exptl_crystal_recrystallization_method 'Re-crystallisation from solvent: CHCl3'
_exptl_crystal_size_max          0.736
_exptl_crystal_size_mid          0.372
_exptl_crystal_size_min          0.206
_refine_diff_density_max         0.24
_refine_diff_density_min         -0.20
_refine_ls_extinction_method     None
_refine_ls_goodness_of_fit_ref   0.9382
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     299
_refine_ls_number_reflns         2031
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0368
_refine_ls_R_factor_gt           0.0331
_refine_ls_shift/su_max          0.0002314
_refine_ls_shift/su_mean         0.0000321
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
;
 Method, part 1, Chebychev polynomial, (Watkin, 1994, Prince, 1982) 
 [weight] = 1.0/[A~0~*T~0~(x)+A~1~*T~1~(x) ... +A~n-1~]*T~n-1~(x)] 
 where A~i~ are the Chebychev coefficients listed below and x= Fcalc/Fmax 
 Method = Robust Weighting (Prince, 1982) 
 W = [weight] * [1-(deltaF/6*sigmaF)^2^]^2^ 
 A~i~ are: 
 3.25 4.40 1.29 
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0825
_refine_ls_wR_factor_gt          0.0810
_refine_ls_wR_factor_ref         0.0810
_reflns_limit_h_max              9
_reflns_limit_h_min              0
_reflns_limit_k_max              16
_reflns_limit_k_min              0
_reflns_limit_l_max              22
_reflns_limit_l_min              0
_reflns_number_gt                2031
_reflns_number_total             2179
_reflns_threshold_expression     I>2.0\s(I)
_oxford_diffrn_Wilson_B_factor   0.00
_oxford_diffrn_Wilson_scale      0.00
_oxford_refine_ls_r_factor_ref   0.0331
_oxford_refine_ls_scale          0.2205(2)
_oxford_reflns_number_all        2167
_oxford_reflns_threshold_expression_ref I>2.0\s(I)
_iucr_refine_instructions_details_constraints
;
FULL C(1,X'S,U'S) UNTIL C(26), H(11,X'S,U[ISO]) UNTIL LAST 
END                                                                             
;
_iucr_refine_instructions_details_restraints
;
NO 
END                                                                             
;
_cod_data_source_file            c6cp07552e2.cif
_cod_data_source_block           1
_cod_depositor_comments
'Adding full bibliography for 7227334--7227338.cif.'
_cod_original_sg_symbol_H-M      'P 21 21 21 '
_cod_database_code               7227336