The inner-salt zwitterion, the dihydrochloride dihydrate and the dimethyl sulfoxide disolvate of 3,6-bis(pyridin-2-yl)pyrazine-2,5-dicarboxylic acid
Wang, Yi; Stoeckli-Evans, Helen; Acta Crystallographica Section C 68 (2012) o431–o435; doi:10.1107/S0108270112039534

data_2018631
_publ_section_title
;
 The inner-salt zwitterion, the dihydrochloride dihydrate and the dimethyl
 sulfoxide disolvate of 3,6-bis(pyridin-2-yl)pyrazine-2,5-dicarboxylic
 acid
;
_journal_coeditor_code           FG3272
_journal_issue                   11
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              o431
_journal_page_last               o435
_journal_paper_doi               10.1107/S0108270112039534
_journal_volume                  68
_journal_year                    2012
_chemical_formula_iupac          'C16 H10 N4 O4'
_chemical_formula_moiety         'C16 H10 N4 O4'
_chemical_formula_sum            'C16 H10 N4 O4'
_chemical_formula_weight         322.28
_chemical_name_systematic
;
5-Carboxy-3-(pyridin-1-ium-2-yl)-6-(pyridin-2-yl)pyrazine-2-carboxylate
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_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                 93.890(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   8.304(3)
_cell_length_b                   9.6840(10)
_cell_length_c                   17.802(2)
_cell_measurement_reflns_used    17
_cell_measurement_temperature    213(2)
_cell_measurement_theta_max      19.0
_cell_measurement_theta_min      14.0
_cell_volume                     1428.3(6)
_computing_cell_refinement       'STADI-4 Software (Stoe & Cie, 1997)'
_computing_data_collection       'STADI-4 Software (Stoe & Cie, 1997)'
_computing_data_reduction        'X-RED (Stoe & Cie, 1997)'
_computing_molecular_graphics
;
PLATON (Spek, 2009) and Mercury (Macrae <i>et al.</i>, 2008)
;
_computing_publication_material
;
SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and
publCIF (Westrip, 2010)
;
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      213(2)
_diffrn_measured_fraction_theta_full 0.948
_diffrn_measured_fraction_theta_max 0.948
_diffrn_measurement_device_type  'Stoe AED-2 four-circle'
_diffrn_measurement_method       2\q/\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  0.0869
_diffrn_reflns_av_sigmaI/netI    0.0534
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            2502
_diffrn_reflns_theta_full        24.98
_diffrn_reflns_theta_max         24.98
_diffrn_reflns_theta_min         2.29
_diffrn_standards_decay_%        2
_diffrn_standards_interval_time  60
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    0.112
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.499
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       rod
_exptl_crystal_F_000             664
_exptl_crystal_size_max          0.49
_exptl_crystal_size_mid          0.27
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.241
_refine_diff_density_min         -0.330
_refine_ls_extinction_coef       0.007(2)
_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   1.085
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     226
_refine_ls_number_reflns         2371
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.086
_refine_ls_R_factor_all          0.0867
_refine_ls_R_factor_gt           0.0613
_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^)+(0.0837P)^2^+0.1644P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1441
_refine_ls_wR_factor_ref         0.1650
_reflns_number_gt                1731
_reflns_number_total             2371
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            fg3272.cif
_cod_data_source_block           Ia
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               2018631
_cod_database_fobs_code          2018631