Structures of N-acetyl-DL-isoleucine, N-acetyl-DL-alloisoleucine and their ammonium salts; role of ammonium ions in crystal structure formation.
Yajima, Tatsuo; Kimura, Makiko; Hori, Yoshihiro; Shiraiwa, Tadashi; Acta crystallographica Section B, Structural science, crystal engineering and materials 72 (2016) 650–657; doi:10.1107/S2052520616007319

data_2311692
_publ_section_title
;
 Structures of N-acetyl-DL-isoleucine, N-acetyl-DL-alloisoleucine and
 their ammonium salts; role of ammonium ions in crystal structure
 formation.
;
_journal_issue                   'Pt 4'
_journal_name_full
'Acta crystallographica Section B, Structural science, crystal engineering and materials'
_journal_page_first              650
_journal_page_last               657
_journal_paper_doi               10.1107/S2052520616007319
_journal_volume                  72
_journal_year                    2016
_chemical_formula_moiety         'C8 H18 N2 O3'
_chemical_formula_sum            'C8 H18 N2 O3'
_chemical_formula_weight         190.24
_chemical_melting_point_gt       133
_chemical_melting_point_lt       135
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.0000
_cell_angle_beta                 96.126(8)
_cell_angle_gamma                90.0000
_cell_formula_units_Z            4
_cell_length_a                   7.907(4)
_cell_length_b                   5.843(3)
_cell_length_c                   23.633(10)
_cell_measurement_reflns_used    1083
_cell_measurement_temperature    123
_cell_measurement_theta_max      27.41
_cell_measurement_theta_min      8.23
_cell_volume                     1085.6(9)
_computing_cell_refinement       'RAPID AUTO'
_computing_data_collection       'RAPID AUTO (Rigaku, 2006)'
_computing_data_reduction        'RAPID AUTO'
_computing_molecular_graphics    'CrystalStructure 4.0'
_computing_publication_material  'CrystalStructure 4.0 (Rigaku, 2010)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SIR2004 (Burla, et al., 2005)'
_diffrn_ambient_temperature      123
_diffrn_detector_area_resol_mean 10.000
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'Rigaku R-AXIS RAPID'
_diffrn_measurement_method       \w
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0257
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       30
_diffrn_reflns_limit_l_min       -30
_diffrn_reflns_number            10080
_diffrn_reflns_theta_full        27.46
_diffrn_reflns_theta_max         27.46
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.088
_exptl_absorpt_correction_T_max  0.994
_exptl_absorpt_correction_T_min  0.931
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'ABSCOR (Rigaku, 1995)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.164
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       platelet
_exptl_crystal_F_000             416.00
_exptl_crystal_size_max          0.340
_exptl_crystal_size_mid          0.130
_exptl_crystal_size_min          0.070
_refine_diff_density_max         0.370
_refine_diff_density_min         -0.220
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.052
_refine_ls_hydrogen_treatment    refxyz
_refine_ls_number_parameters     190
_refine_ls_number_reflns         2475
_refine_ls_number_restraints     0
_refine_ls_R_factor_gt           0.0364
_refine_ls_shift/su_max          0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w = 1/[\s^2^(Fo^2^)+(0.0506P)^2^+0.3406P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         0.0980
_reflns_number_gt                2211
_reflns_number_total             2475
_reflns_threshold_expression     F^2^>2.0\s(F^2^)
_cod_data_source_file            lo5008sup1.cif
_cod_data_source_block           Ac-DL-IleNH3
_cod_original_cell_volume        1085.5(8)
_cod_database_code               2311692