An unexpected tetragonal unit cell for <i>N</i>-(<small>L</small>-2-aminobutyryl)-<small>L</small>-serine
Görbitz, Carl Henrik; Yadav, Vitthal N.; Acta Crystallographica Section C 69 (2013) 888–891; doi:10.1107/S0108270113017484

data_2019085
_publ_section_title
;
 An unexpected tetragonal unit cell for
 <i>N</i>-(<small>L</small>-2-aminobutyryl)-<small>L</small>-serine
;
_journal_coeditor_code           QS3026
_journal_issue                   8
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              888
_journal_page_last               891
_journal_paper_doi               10.1107/S0108270113017484
_journal_volume                  69
_journal_year                    2013
_chemical_formula_iupac          'C7 H14 N2 O4'
_chemical_formula_moiety         'C7 H14 N2 O4'
_chemical_formula_sum            'C7 H14 N2 O4'
_chemical_formula_weight         190.20
_chemical_name_common            'Abu-Ser, N-(L-2-aminobutyryl)-L-serine'
_chemical_name_systematic
;
(<i>S</i>)-2-[(<i>S</i>)-2-Azaniumylbutanamido]-3-hydroxypropanoate
;
_space_group_IT_number           79
_symmetry_cell_setting           tetragonal
_symmetry_space_group_name_Hall  'I 4'
_symmetry_space_group_name_H-M   'I 4'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   18.335(7)
_cell_length_b                   18.335(7)
_cell_length_c                   5.141(2)
_cell_measurement_reflns_used    2704
_cell_measurement_temperature    105(2)
_cell_measurement_theta_max      25.07
_cell_measurement_theta_min      3.14
_cell_volume                     1728.3(12)
_computing_cell_refinement       'SAINT-Plus (Bruker, 2007)'
_computing_data_collection       'APEX2 (Bruker, 2007)'
_computing_data_reduction        'SAINT-Plus (Bruker, 2007)'
_computing_molecular_graphics    'SHELXTL (Sheldrick, 2008)'
_computing_publication_material  'SHELXTL (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      105(2)
_diffrn_detector_area_resol_mean 8.3
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'Bruker APEXII CCD area-detector'
_diffrn_measurement_method
'Sets of exposures each taken over 0.5\% \w rotation'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0836
_diffrn_reflns_av_sigmaI/netI    0.0570
_diffrn_reflns_limit_h_max       21
_diffrn_reflns_limit_h_min       -21
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       6
_diffrn_reflns_limit_l_min       -6
_diffrn_reflns_number            6072
_diffrn_reflns_theta_full        25.11
_diffrn_reflns_theta_max         25.11
_diffrn_reflns_theta_min         2.22
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.120
_exptl_absorpt_correction_T_max  0.993
_exptl_absorpt_correction_T_min  0.788
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Bruker, 2007)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.462
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             816
_exptl_crystal_size_max          0.39
_exptl_crystal_size_mid          0.09
_exptl_crystal_size_min          0.06
_refine_diff_density_max         0.376
_refine_diff_density_min         -0.304
_refine_ls_extinction_coef       0.014(3)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL97 (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   1.301
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     177
_refine_ls_number_reflns         862
_refine_ls_number_restraints     767
_refine_ls_restrained_S_all      0.946
_refine_ls_R_factor_all          0.0863
_refine_ls_R_factor_gt           0.0800
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w = 1/[\s^2^(Fo^2^)+(0.0359P)^2^+9.6883P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1922
_refine_ls_wR_factor_ref         0.1950
_reflns_number_gt                780
_reflns_number_total             862
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            qs3026.cif
_cod_data_source_block           I
_cod_original_cell_volume        1728.1(12)
_cod_database_code               2019085
_cod_database_fobs_code          2019085