Conformational preferences in the β-peptide oligomers of cis-2-amino-1-fluorocyclobutane-1-carboxylic acid
Hassoun, Ammar; Grison, Claire M.; Guillot, Régis; Boddaert, Thomas; Aitken, David J.; New J. Chem. 39 (2015) 3270–; doi:10.1039/C4NJ01929F

data_7054573
_publ_section_title
;
 Conformational preferences in the \b-peptide oligomers of
 cis-2-amino-1-fluorocyclobutane-1-carboxylic acid
;
_journal_issue                   5
_journal_name_full               'New J. Chem.'
_journal_page_first              3270
_journal_paper_doi               10.1039/C4NJ01929F
_journal_volume                  39
_journal_year                    2015
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C32 H40 F4 N4 O7'
_chemical_formula_sum            'C32 H40 F4 N4 O7'
_chemical_formula_weight         668.68
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_Int_Tables_number      19
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_audit_update_record
;
2014-10-09 deposited with the CCDC.
2014-12-01 downloaded from the CCDC.
;
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   5.3500(9)
_cell_length_b                   20.200(3)
_cell_length_c                   29.927(4)
_cell_measurement_temperature    100(1)
_cell_volume                     3234.2(8)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      100(1)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.997
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0902
_diffrn_reflns_av_sigmaI/netI    0.0970
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       28
_diffrn_reflns_limit_k_min       -28
_diffrn_reflns_limit_l_max       36
_diffrn_reflns_limit_l_min       -42
_diffrn_reflns_number            50560
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         30.49
_diffrn_reflns_theta_min         1.22
_diffrn_source                   'fine-focus sealed tube'
_diffrn_source_type              'kappa X8 APEX II Bruker ICMMO'
_exptl_absorpt_coefficient_mu    0.112
_exptl_absorpt_correction_T_max  0.9978
_exptl_absorpt_correction_T_min  0.9801
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.373
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             1408
_exptl_crystal_size_max          0.18
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.762
_refine_diff_density_min         -0.396
_refine_diff_density_rms         0.077
_refine_ls_abs_structure_details
;
 Flack x determined using 2038 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons and Flack (2004), Acta Cryst. A60, s61).
;
_refine_ls_abs_structure_Flack   0.2(4)
_refine_ls_extinction_coef       0.0059(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   1.031
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     428
_refine_ls_number_reflns         9833
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.031
_refine_ls_R_factor_all          0.1212
_refine_ls_R_factor_gt           0.0682
_refine_ls_shift/su_max          0.020
_refine_ls_shift/su_mean         0.003
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0833P)^2^+0.3628P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1483
_refine_ls_wR_factor_ref         0.1709
_reflns_number_gt                6330
_reflns_number_total             9833
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c4nj01929f3.cif
_cod_data_source_block           12
_cod_depositor_comments
'Adding full bibliography for 7054572--7054573.cif.'
_cod_database_code               7054573