An efficient pathway to high persistence length helicenes from scalable [4]-helicene synthons
Reinhard, Garrett L.; Dowling, Reed; Hewitt, Patrick; Varshney, Vikas; Simone, Davide L.; RSC Advances 15 (2025) 20935–20943; doi:10.1039/D5RA02685G

data_7250573
_publ_section_title
;
 An efficient pathway to high persistence length helicenes from scalable
 [4]-helicene synthons
;
_journal_issue                   26
_journal_name_full               'RSC Advances'
_journal_page_first              20935
_journal_page_last               20943
_journal_paper_doi               10.1039/D5RA02685G
_journal_volume                  15
_journal_year                    2025
_chemical_formula_sum            'C21 H25 Br O3'
_chemical_formula_weight         405.32
_chemical_name_systematic
;
6-bromonaphthalen-2-yl (2-isopropyl-5-methyl-cyclohexyl) carbonate
;
_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'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2016/6
_audit_update_record
;
2025-06-03 deposited with the CCDC.	2025-06-11 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 100.4620(10)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   11.28950(10)
_cell_length_b                   6.42040(10)
_cell_length_c                   13.5684(2)
_cell_measurement_reflns_used    8830
_cell_measurement_temperature    200(2)
_cell_measurement_theta_max      76.4430
_cell_measurement_theta_min      3.9620
_cell_volume                     967.13(2)
_computing_cell_refinement       'CrysAlisPro 1.171.42.94a (Rigaku OD, 2023)'
_computing_data_collection       'CrysAlisPro 1.171.42.94a (Rigaku OD, 2023)'
_computing_data_reduction        'CrysAlisPro 1.171.42.94a (Rigaku OD, 2023)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL-2016/6 (Sheldrick, 2016)'
_computing_structure_solution    'SHELXT 2014/5 (Sheldrick, 2014)'
_diffrn_ambient_temperature      200(2)
_diffrn_detector_area_resol_mean 10.0000
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.951
_diffrn_measurement_device_type  'XtaLAB Synergy, Dualflex, HyPix'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0167
_diffrn_reflns_av_unetI/netI     0.0145
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.951
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            10097
_diffrn_reflns_point_group_measured_fraction_full 0.787
_diffrn_reflns_point_group_measured_fraction_max 0.729
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         76.677
_diffrn_reflns_theta_min         3.982
_diffrn_source                   'micro-focus sealed X-ray tube'
_exptl_absorpt_coefficient_mu    3.023
_exptl_absorpt_correction_T_max  0.46820
_exptl_absorpt_correction_T_min  0.41536
_exptl_absorpt_correction_type   sphere
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.42.94a (Rigaku Oxford Diffraction, 2023)
Spherical absorption correction
using equivalent radius and absorption coefficient.
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            'clear colorless'
_exptl_crystal_density_diffrn    1.392
_exptl_crystal_description       sphere
_exptl_crystal_F_000             420
_exptl_crystal_recrystallization_method
'Re-crystallisation from solvent: Methanol'
_exptl_crystal_size_max          0.061
_exptl_crystal_size_mid          0.046
_exptl_crystal_size_min          0.013
_exptl_crystal_size_rad          0.400
_refine_diff_density_max         0.271
_refine_diff_density_min         -0.250
_refine_diff_density_rms         0.033
_refine_ls_abs_structure_details
;
 Flack x determined using 834 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.039(9)
_refine_ls_extinction_coef       0.0045(3)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2016/6 (Sheldrick 2016)'
_refine_ls_goodness_of_fit_ref   1.033
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     230
_refine_ls_number_reflns         2972
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.033
_refine_ls_R_factor_all          0.0212
_refine_ls_R_factor_gt           0.0209
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0326P)^2^+0.1788P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0548
_refine_ls_wR_factor_ref         0.0550
_reflns_Friedel_coverage         0.402
_reflns_Friedel_fraction_full    0.532
_reflns_Friedel_fraction_max     0.461
_reflns_number_gt                2934
_reflns_number_total             2972
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5ra02685g2.cif
_cod_data_source_block           1_menthylnaphthalene
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               7250573
_shelx_shelxl_version_number     2016/6
_shelx_res_checksum              24617