Conformational analysis of helical aminoisobutyric acid (Aib) oligomers bearing C-terminal ester Schellman motifs.
Pike, Sarah J.; Raftery, James; Webb, Simon J.; Clayden, Jonathan; Organic & biomolecular chemistry 12 (2014) 4124–4131; doi:10.1039/c4ob00268g

data_7153788
_publ_section_title
;
 Conformational analysis of helical aminoisobutyric acid (Aib) oligomers
 bearing C-terminal ester Schellman motifs.
;
_journal_issue                   24
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              4124
_journal_page_last               4131
_journal_paper_doi               10.1039/c4ob00268g
_journal_volume                  12
_journal_year                    2014
_chemical_formula_sum            'C12 H22 N4 O3'
_chemical_formula_weight         270.34
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_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
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.23450(10)
_cell_length_b                   10.44030(10)
_cell_length_c                   15.8938(2)
_cell_measurement_reflns_used    6954
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      72.43
_cell_measurement_theta_min      5.07
_cell_volume                     1532.34(3)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.988
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0191
_diffrn_reflns_av_sigmaI/netI    0.0196
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            8405
_diffrn_reflns_theta_full        66.60
_diffrn_reflns_theta_max         72.42
_diffrn_reflns_theta_min         5.07
_exptl_absorpt_coefficient_mu    0.704
_exptl_absorpt_correction_T_max  0.8605
_exptl_absorpt_correction_T_min  0.794158
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            white
_exptl_crystal_density_diffrn    1.172
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             584
_exptl_crystal_size_max          0.28
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.22
_refine_diff_density_max         0.244
_refine_diff_density_min         -0.247
_refine_diff_density_rms         0.031
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.01(14)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.069
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     183
_refine_ls_number_reflns         2966
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.069
_refine_ls_R_factor_all          0.0265
_refine_ls_R_factor_gt           0.0261
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0343P)^2^+0.3011P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0674
_refine_ls_wR_factor_ref         0.0677
_reflns_number_gt                2923
_reflns_number_total             2966
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c4ob00268g2.cif
_cod_data_source_block           s3910ma
_cod_depositor_comments
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The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/usr/data/users/saulius/crontab/automatic-downloads/rss-feeds/RSC/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 2281 2013-09-26 08:29:07Z andrius 

 Adding full bibliography for 7153788--7153792.cif.
;
_cod_original_sg_symbol_H-M      P2(1)2(1)2(1)
_cod_database_code               7153788