A bicyclic unit reversal to stabilize the 12/14-helix in mixed homochiral oligoureas.
Milbeo, Pierre; Simon, Matthieu; Didierjean, Claude; Wenger, Emmanuel; Aubert, Emmanuel; Martinez, Jean; Amblard, Muriel; Calmès, Monique; Legrand, Baptiste; Chemical communications (Cambridge, England) 56 (2020) 7921–7924; doi:10.1039/d0cc02902e

data_7126621
_publ_section_title
;
 A bicyclic unit reversal to stabilize the 12/14-helix in mixed homochiral
 oligoureas.
;
_journal_issue                   57
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              7921
_journal_page_last               7924
_journal_paper_doi               10.1039/d0cc02902e
_journal_volume                  56
_journal_year                    2020
_chemical_absolute_configuration syn
_chemical_formula_sum            'C49 H65 Br N10 O7'
_chemical_formula_weight         986.02
_space_group_crystal_system      triclinic
_space_group_IT_number           1
_space_group_name_Hall           'P 1'
_space_group_name_H-M_alt        'P 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2018/3
_audit_update_record
;
2020-02-07 deposited with the CCDC.	2020-05-27 downloaded from the CCDC.
;
_cell_angle_alpha                90.333(2)
_cell_angle_beta                 103.664(2)
_cell_angle_gamma                108.641(2)
_cell_formula_units_Z            1
_cell_length_a                   10.0071(2)
_cell_length_b                   10.6965(2)
_cell_length_c                   12.3292(3)
_cell_measurement_reflns_used    17844
_cell_measurement_temperature    105(1)
_cell_measurement_theta_max      32.4580
_cell_measurement_theta_min      2.4890
_cell_volume                     1210.36(5)
_computing_structure_refinement  'SHELXL-2018/3 (Sheldrick, 2018)'
_computing_structure_solution    'SHELXT 2014/5 (Sheldrick, 2014)'
_diffrn_ambient_temperature      105(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'SuperNova, Dual, Cu at zero, Atlas'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0413
_diffrn_reflns_av_unetI/netI     0.0395
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            56632
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.999
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         29.998
_diffrn_reflns_theta_min         2.219
_exptl_absorpt_coefficient_mu    0.911
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.540
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.38.46 (Rigaku Oxford Diffraction, 2015)
Numerical absorption correction based on gaussian integration over
			a multifaceted crystal model
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.353
_exptl_crystal_description       block
_exptl_crystal_F_000             520
_exptl_crystal_size_max          0.400
_exptl_crystal_size_mid          0.160
_exptl_crystal_size_min          0.120
_refine_diff_density_max         0.500
_refine_diff_density_min         -0.358
_refine_diff_density_rms         0.052
_refine_ls_abs_structure_details
;
 Flack x determined using 5663 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.012(2)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.062
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     605
_refine_ls_number_reflns         14084
_refine_ls_number_restraints     3
_refine_ls_restrained_S_all      1.062
_refine_ls_R_factor_all          0.0456
_refine_ls_R_factor_gt           0.0383
_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^)+(0.0410P)^2^+0.3499P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0852
_refine_ls_wR_factor_ref         0.0895
_reflns_Friedel_coverage         0.998
_reflns_Friedel_fraction_full    0.999
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                12840
_reflns_number_total             14084
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d0cc02902e2.cif
_cod_data_source_block           Cpd2-PM04-77
_cod_depositor_comments
'Adding full bibliography for 7126621--7126622.cif.'
_cod_original_cell_volume        1210.35(5)
_cod_database_code               7126621
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_min   0.712
_shelx_estimated_absorpt_t_max   0.899
_shelx_res_checksum              90640