A new molecular scaffold for the formation of supramolecular peptide double helices: the crystallographic insight.
Guha, Samit; Drew, Michael G. B.; Banerjee, Arindam; Organic letters 9 (2007) 1347–1350; doi:10.1021/ol0701870

data_1505339
_publ_section_title
;
 A new molecular scaffold for the formation of supramolecular peptide
 double helices: the crystallographic insight.
;
_journal_issue                   7
_journal_name_full               'Organic letters'
_journal_page_first              1347
_journal_page_last               1350
_journal_paper_doi               10.1021/ol0701870
_journal_volume                  9
_journal_year                    2007
_chemical_formula_sum            'C12 H16 N2 O3'
_chemical_formula_weight         236.27
_space_group_IT_number           4
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_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                 97.293(13)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   8.1292(11)
_cell_length_b                   5.7648(8)
_cell_length_c                   12.434(2)
_cell_measurement_temperature    150(2)
_cell_volume                     577.98(15)
_computing_cell_refinement       'Crysalis, Oxford Diffraction'
_computing_data_collection       'Crysalis, Oxford Diffraction'
_computing_data_reduction        'Crysalis, Oxford Diffraction'
_computing_molecular_graphics    PLATON(Spek,2004)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.969
_diffrn_measured_fraction_theta_max 0.969
_diffrn_measurement_device       'Oxford Diffaction X-Calibur System'
_diffrn_measurement_method       '321 frames, counting time 10 s.'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
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_diffrn_reflns_limit_l_min       -16
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_diffrn_reflns_theta_min         3.19
_exptl_absorpt_coefficient_mu    0.099
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            white
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_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             252
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_refine_ls_abs_structure_Flack   1(2)
_refine_ls_extinction_coef       0.028(8)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
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_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
;
  w=1/[\s^2^(Fo^2^)+(0.0495P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3 
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1255
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_reflns_threshold_expression     >2sigma(I)
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