Helix-Forming Propensity of Aliphatic Urea Oligomers Incorporating Noncanonical Residue Substitution Patterns
Nagendar Pendem; Céline Douat; Paul Claudon; Michel Laguerre; Sabine Castano; Bernard Desbat; Dominique Cavagnat; Eric Ennifar; Brice Kauffmann; Gilles Guichard; Journal of the American Chemical Society 135 (2013) 4884–4892; doi:10.1021/ja401151v

data_4119514
_publ_section_title
;
 Helix-Forming Propensity of Aliphatic Urea Oligomers Incorporating
 Noncanonical Residue Substitution Patterns
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              4884
_journal_page_last               4892
_journal_paper_doi               10.1021/ja401151v
_journal_volume                  135
_journal_year                    2013
_chemical_formula_sum            'C54.5 H63.75 F3 N12 O8.5'
_chemical_formula_weight         1079.93
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_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
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 117.49(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   22.104(4)
_cell_length_b                   25.028(5)
_cell_length_c                   23.517(5)
_cell_measurement_temperature    213(2)
_cell_volume                     11541(5)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SUPERFLIP (Palatinus, 2007)'
_diffrn_ambient_temperature      213(2)
_diffrn_measured_fraction_theta_full 0.964
_diffrn_measured_fraction_theta_max 0.964
_diffrn_measurement_method       'omega scan'
_diffrn_radiation_monochromator  'Osmic mirrors'
_diffrn_radiation_source         'rotating anode'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0744
_diffrn_reflns_av_sigmaI/netI    0.0895
_diffrn_reflns_limit_h_max       22
_diffrn_reflns_limit_h_min       -27
_diffrn_reflns_limit_k_max       28
_diffrn_reflns_limit_k_min       -30
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            136732
_diffrn_reflns_theta_full        72.68
_diffrn_reflns_theta_max         72.68
_diffrn_reflns_theta_min         2.12
_exptl_absorpt_coefficient_mu    0.769
_exptl_absorpt_correction_T_max  1
_exptl_absorpt_correction_T_min  0.911
_exptl_absorpt_correction_type   empirical
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.243
_exptl_crystal_description       needle
_exptl_crystal_F_000             4558
_exptl_crystal_size_max          0.1
_exptl_crystal_size_mid          0.01
_exptl_crystal_size_min          0.01
_refine_diff_density_max         0.724
_refine_diff_density_min         -0.533
_refine_diff_density_rms         0.137
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.00(17)
_refine_ls_extinction_coef       0.00129(9)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.016
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     2801
_refine_ls_number_reflns         41515
_refine_ls_number_restraints     4
_refine_ls_restrained_S_all      1.016
_refine_ls_R_factor_all          0.1433
_refine_ls_R_factor_gt           0.1005
_refine_ls_shift/su_max          0.090
_refine_ls_shift/su_mean         0.066
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.2000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2672
_refine_ls_wR_factor_ref         0.3210
_reflns_number_gt                26686
_reflns_number_total             41515
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja401151v_si_003.cif
_cod_data_source_block           shelxl
_cod_original_cell_volume        11541(4)
_cod_original_formula_sum        'C54.50 H63.75 F3 N12 O8.50'
_cod_database_code               4119514