Hydrogen bonding in the inner-salt zwitterion and in two different charged forms of 5,6-bis(2-pyridyl)pyrazine-2,3-dicarboxylic acid
Alfonso, Montserrat; Wang, Yi; Stoeckli-Evans, Helen; Acta Crystallographica Section C 57 (2001) 1184–1188; doi:10.1107/S0108270101010757

data_2012255
_publ_section_title
;
 Hydrogen bonding in the inner-salt zwitterion and in two different
 charged forms of 5,6-bis(2-pyridyl)pyrazine-2,3-dicarboxylic acid
;
_journal_issue                   10
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              1184
_journal_page_last               1188
_journal_paper_doi               10.1107/S0108270101010757
_journal_volume                  57
_journal_year                    2001
_chemical_formula_moiety         'C16 H11 N4 O4 + , Cl - , 2.25H2 O'
_chemical_formula_sum            'C16 H15.5 Cl N4 O6.25'
_chemical_formula_weight         399.27
_chemical_name_systematic
;
6-Carboxy-5-carboxylatopyrazine-2,3-diyldi-2-pyridinium chloride 2.25 hydrate
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-I 2ya'
_symmetry_space_group_name_H-M   'I 1 2/a 1'
_audit_creation_method           SHELXL97
_cell_angle_alpha                90
_cell_angle_beta                 90.559(11)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   19.5883(17)
_cell_length_b                   8.0623(5)
_cell_length_c                   22.936(2)
_cell_measurement_reflns_used    5000
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      25.93
_cell_measurement_theta_min      2.08
_cell_volume                     3622.0(5)
_computing_cell_refinement       'CELL (Stoe & Cie, 2000)'
_computing_data_collection       'EXPOSE (Stoe & Cie, 2000)'
_computing_data_reduction        'INTEGRATE (Stoe & Cie, 2000)'
_computing_molecular_graphics    'PLATON99 (Spek, 1990)'
_computing_publication_material  SHELXL97
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_detector_area_resol_mean 0.81\%A
_diffrn_measured_fraction_theta_full .990
_diffrn_measured_fraction_theta_max .990
_diffrn_measurement_device_type  'Stoe IPDS'
_diffrn_measurement_method       '\f oscillation'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     .71073
_diffrn_reflns_av_R_equivalents  .055
_diffrn_reflns_av_sigmaI/netI    .070
_diffrn_reflns_limit_h_max       23
_diffrn_reflns_limit_h_min       -24
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            13718
_diffrn_reflns_theta_full        25.93
_diffrn_reflns_theta_max         25.93
_diffrn_reflns_theta_min         2.08
_diffrn_standards_decay_%        0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    .255
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.464
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       rod
_exptl_crystal_F_000             1652
_exptl_crystal_size_max          .5
_exptl_crystal_size_mid          .2
_exptl_crystal_size_min          .1
_refine_diff_density_max         .63
_refine_diff_density_min         -.26
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   .823
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     327
_refine_ls_number_reflns         3488
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      .823
_refine_ls_R_factor_all          .081
_refine_ls_R_factor_gt           .039
_refine_ls_shift/su_max          .027
_refine_ls_shift/su_mean         .001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w = 1/[\s^2^(Fo^2^)+(0.05P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         .093
_reflns_number_gt                1943
_reflns_number_total             3488
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            gd1159.cif
_cod_data_source_block           II
_cod_depositor_comments
;
The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'none' was changed to '?' - the
value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 
;
_cod_original_sg_symbol_H-M      'I 2/a'
_cod_database_code               2012255
_cod_database_fobs_code          2012255