X-ray crystallographic structures of enamine and amine Schiff bases of pyridoxal and its 1:1 hydrogen-bonded complexes with benzoic acid derivatives: evidence for coupled inter- and intramolecular proton transfer
Sharif, Shasad; Powell, Douglas R.; Schagen, David; Steiner, Thomas; Toney, Michael D.; Fogle, Emily; Limbach, Hans-Heinrich; Acta Crystallographica Section B 62 (2006) 480–487; doi:10.1107/S0108768105040590

data_2100502
_publ_section_title
;
 X-ray crystallographic structures of enamine and amine Schiff bases of
 pyridoxal and its 1:1 hydrogen-bonded complexes with benzoic acid
 derivatives: evidence for coupled inter- and intramolecular proton
 transfer
;
_journal_coeditor_code           SN5027
_journal_issue                   3
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              480
_journal_page_last               487
_journal_paper_doi               10.1107/S0108768105040590
_journal_volume                  62
_journal_year                    2006
_chemical_formula_moiety         'C15 H16 N2 O2'
_chemical_formula_sum            'C15 H16 N2 O2'
_chemical_formula_weight         256.30
_space_group_IT_number           14
_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
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 93.65(8)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   4.001(4)
_cell_length_b                   25.09(3)
_cell_length_c                   12.940(11)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    295(2)
_cell_measurement_theta_max      15.0
_cell_measurement_theta_min      8.0
_cell_volume                     1296(2)
_computing_molecular_graphics    'SHELXTL (Sheldrick, 2000)'
_computing_publication_material  'SHELXTL (Sheldrick, 2000)'
_computing_structure_refinement  'SHELXTL (Sheldrick, 2000)'
_computing_structure_solution    'SHELXTL (Sheldrick, 2000)'
_diffrn_ambient_temperature      295(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Stoe four-circle'
_diffrn_measurement_method       \w
_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  0.1499
_diffrn_reflns_av_sigmaI/netI    0.2297
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       29
_diffrn_reflns_limit_k_min       -29
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            2631
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         2.26
_diffrn_standards_decay_%        3
_diffrn_standards_interval_time  30
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.088
_exptl_absorpt_correction_T_max  0.991
_exptl_absorpt_correction_T_min  0.962
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.313
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             544
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.188
_refine_diff_density_min         -0.266
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.004
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     178
_refine_ls_number_reflns         2287
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.004
_refine_ls_R_factor_all          0.2658
_refine_ls_R_factor_gt           0.0760
_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^)+(0.0540P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1508
_refine_ls_wR_factor_ref         0.2140
_reflns_number_gt                874
_reflns_number_total             2287
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            sn5027.cif
_cod_data_source_block           compound_I_
_cod_database_code               2100502