Clarifying the structures of imidines: using crystallographic characterization to identify tautomers and localized systems of π-bonding.
Aristov, Michael M.; Geng, Han; Harris, James W.; Berry, John F.; Acta crystallographica. Section C, Structural chemistry 79 (2023) 133–141; doi:10.1107/S2053229623002036

data_2022703
_publ_section_title
;
 Clarifying the structures of imidines: using crystallographic
 characterization to identify tautomers and localized systems of
 &#x3c0;-bonding.
;
_journal_coeditor_code           EP3031
_journal_issue                   'Pt 4'
_journal_name_full
'Acta crystallographica. Section C, Structural chemistry'
_journal_page_first              133
_journal_page_last               141
_journal_paper_doi               10.1107/S2053229623002036
_journal_volume                  79
_journal_year                    2023
_chemical_formula_iupac          'C5 H8 N2 O'
_chemical_formula_moiety         'C5 H8 N2 O'
_chemical_formula_sum            'C5 H8 N2 O'
_chemical_formula_weight         112.13
_chemical_name_systematic
;
6-Amino-4,5-dihydropyridin-2(3<i>H</i>)-one
;
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     dual
_audit_creation_method
;
Olex2 1.2-beta
(compiled 2018.05.29 svn.r3508 for OlexSys, GUI svn.r5506)
;
_cell_angle_alpha                84.975(13)
_cell_angle_beta                 71.693(13)
_cell_angle_gamma                63.889(12)
_cell_formula_units_Z            2
_cell_length_a                   6.3296(19)
_cell_length_b                   7.0222(19)
_cell_length_c                   7.351(2)
_cell_measurement_reflns_used    2665
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      32.744
_cell_measurement_theta_min      2.924
_cell_volume                     278.05(14)
_computing_cell_refinement
;
SAINT-Plus (Bruker, 2016)
;
_computing_data_collection
;
APEX3 (Bruker, 2016)
;
_computing_data_reduction
;
SAINT-Plus (Bruker, 2016)
;
_computing_molecular_graphics
;
OLEX2 (Dolomanov <i>et al.</i>, 2009)
;
_computing_publication_material
;
OLEX2 (Dolomanov <i>et al.</i>, 2009)
;
_computing_structure_refinement
;
SHELXL2018 (Sheldrick, 2015<i>b</i>)
;
_computing_structure_solution
;
SHELXT2014 (Sheldrick, 2015<i>a</i>)
;
_diffrn_ambient_temperature      100.0
_diffrn_detector                 'charge-coupled device (CCD) area detector'
_diffrn_detector_area_resol_mean 7.9
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.962
_diffrn_measurement_device       'three-circle diffractometer'
_diffrn_measurement_device_type  'Bruker APEXII Quazar'
_diffrn_measurement_method       '0.5\ \w and 0.5\ \f scans'
_diffrn_radiation_monochromator  'mirror optics'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0336
_diffrn_reflns_av_unetI/netI     0.0315
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            9023
_diffrn_reflns_theta_full        25.000
_diffrn_reflns_theta_max         33.171
_diffrn_reflns_theta_min         2.924
_diffrn_source                   'microfocus sealed X-ray tube'
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.097
_exptl_absorpt_correction_T_max  0.9910
_exptl_absorpt_correction_T_min  0.9292
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
(SADABS; Bruker, 2016)
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.339
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             120
_exptl_crystal_size_max          0.161
_exptl_crystal_size_mid          0.051
_exptl_crystal_size_min          0.01
_refine_diff_density_max         0.442
_refine_diff_density_min         -0.267
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.059
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     79
_refine_ls_number_reflns         2048
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.059
_refine_ls_R_factor_all          0.0550
_refine_ls_R_factor_gt           0.0426
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0544P)^2^+0.1043P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1125
_refine_ls_wR_factor_ref         0.1195
_reflns_number_gt                1680
_reflns_number_total             2048
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ep3031sup1.cif
_cod_data_source_block           4
_cod_depositor_comments
'Adding full bibliography for 2022700--2022704.cif.'
_cod_original_cell_volume        278.06(14)
_cod_database_code               2022703
_cod_database_fobs_code          2022703
_shelx_estimated_absorpt_t_min   0.985
_shelx_estimated_absorpt_t_max   0.999
_shelx_hkl_checksum              6193
_shelx_res_checksum              5050