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_7054572
_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 ad
_chemical_formula_moiety         'C19 H27 F N2 O4'
_chemical_formula_sum            'C19 H27 F N2 O4'
_chemical_formula_weight         366.43
_space_group_IT_number           78
_symmetry_cell_setting           tetragonal
_symmetry_Int_Tables_number      78
_symmetry_space_group_name_Hall  'P 4cw'
_symmetry_space_group_name_H-M   'P 43'
_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                   10.1585(4)
_cell_length_b                   10.1585(4)
_cell_length_c                   19.0174(5)
_cell_measurement_reflns_used    9893
_cell_measurement_temperature    100(1)
_cell_measurement_theta_max      32.15
_cell_measurement_theta_min      2.84
_cell_volume                     1962.50(12)
_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 0.986
_diffrn_measured_fraction_theta_max 0.931
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0282
_diffrn_reflns_av_sigmaI/netI    0.0237
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            23939
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         32.15
_diffrn_reflns_theta_min         2.00
_diffrn_source                   'fine-focus sealed tube'
_diffrn_source_type              'kappa X8 APEX II Bruker ICMMO'
_exptl_absorpt_coefficient_mu    0.093
_exptl_absorpt_correction_T_max  0.9835
_exptl_absorpt_correction_T_min  0.9718
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.240
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       bloc
_exptl_crystal_F_000             784
_exptl_crystal_size_max          0.31
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.297
_refine_diff_density_min         -0.165
_refine_diff_density_rms         0.037
_refine_ls_abs_structure_details
;
 Flack x determined using 1790 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons and Flack (2004), Acta Cryst. A60, s61).
;
_refine_ls_abs_structure_Flack   0.01(17)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.028
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     240
_refine_ls_number_reflns         5245
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.028
_refine_ls_R_factor_all          0.0348
_refine_ls_R_factor_gt           0.0321
_refine_ls_shift/su_max          0.004
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0540P)^2^+0.1521P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0833
_refine_ls_wR_factor_ref         0.0851
_reflns_number_gt                4955
_reflns_number_total             5245
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c4nj01929f3.cif
_cod_data_source_block           8
_cod_depositor_comments
'Adding full bibliography for 7054572--7054573.cif.'
_cod_original_cell_volume        1962.50(16)
_cod_database_code               7054572