The crystal structures of three pyrazine-2,5-dicarboxamides: three-dimensional supramolecular structures
Cati, Dilovan S.; Stoeckli-Evans, Helen; Acta Crystallographica Section E 73 (2017) 729–734; doi:10.1107/S2056989017005898

data_2242144
_publ_section_title
;
 The crystal structures of three pyrazine-2,5-dicarboxamides:
 three-dimensional supramolecular structures
;
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              729
_journal_page_last               734
_journal_paper_doi               10.1107/S2056989017005898
_journal_volume                  73
_journal_year                    2017
_chemical_formula_iupac          'C20 H20 N6 O2'
_chemical_formula_moiety         'C20 H20 N6 O2'
_chemical_formula_sum            'C20 H20 N6 O2'
_chemical_formula_weight         376.42
_chemical_name_systematic
3,6-Dimethyl-<i>N</i>^2^,<i>N</i>^5^-bis(pyridin-2-ylmethyl)pyrazine-2,5-dicarboxamide
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2016/6
_cell_angle_alpha                90
_cell_angle_beta                 99.834(6)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   8.7271(5)
_cell_length_b                   5.2950(4)
_cell_length_c                   20.1403(13)
_cell_measurement_reflns_used    22
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      32.00
_cell_measurement_theta_min      20.40
_cell_volume                     917.01(11)
_computing_cell_refinement
;
<i>STADI4</i> (Stoe & Cie, 1997)
;
_computing_data_collection
;
<i>STADI4</i> (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
;
SHELXL2016 (Sheldrick, 2015), PLATON (Spek, 2009)
and publCIF (Westrip, 2010)
;
_computing_structure_refinement
;
SHELXL2014 (Sheldrick, 2015)
;
_computing_structure_solution
;
SHELXS97 (Sheldrick, 2008)
;
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device       'Stoe--Siemens AED2 four-circle'
_diffrn_measurement_method       '\w/2\q scans'
_diffrn_radiation_monochromator  'plane graphite'
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54186
_diffrn_reflns_av_R_equivalents  0.0150
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       5
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            2576
_diffrn_reflns_theta_full        59.574
_diffrn_reflns_theta_max         59.574
_diffrn_reflns_theta_min         4.456
_diffrn_standards_decay_%        2
_diffrn_standards_interval_time  60
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    0.754
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.955
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
(MULABS; Spek, 2009)
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.363
_exptl_crystal_description       rod
_exptl_crystal_F_000             396
_exptl_crystal_size_max          0.46
_exptl_crystal_size_mid          0.19
_exptl_crystal_size_min          0.19
_refine_diff_density_max         0.177
_refine_diff_density_min         -0.124
_refine_ls_extinction_coef       0.0124(10)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method
;
SHELXL2016 (Sheldrick, 2015)
;
_refine_ls_goodness_of_fit_ref   1.051
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     133
_refine_ls_number_reflns         1345
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.051
_refine_ls_R_factor_all          0.0393
_refine_ls_R_factor_gt           0.0354
_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^)+(0.0453P)^2^+0.2943P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0915
_refine_ls_wR_factor_ref         0.0946
_reflns_number_gt                1226
_reflns_number_total             1345
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            hb7672sup1.cif
_cod_data_source_block           II
_cod_database_code               2242144
_cod_database_fobs_code          2242144
_shelx_hkl_checksum              70860
_shelx_res_checksum              70662