2,2',3,3'-Tetramethyl-6,6'-biquinoxaline
Ralph Nicholas Salvatore; Jorden Paul Kass; Ricky Joseph Paul Gibson; Cesar H. Zambrano; Robert D. Pike; Eric Efrain Dueno; Acta Crystallographica Section E 62 (2006) o4547–o4548; doi:10.1107/S1600536806037093

data_2210491
_publ_section_title
;
 2,2',3,3'-Tetramethyl-6,6'-biquinoxaline
;
_journal_coeditor_code           BG2005
_journal_issue                   10
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o4547
_journal_page_last               o4548
_journal_paper_doi               10.1107/S1600536806037093
_journal_volume                  62
_journal_year                    2006
_chemical_formula_iupac          'C20 H18 N4'
_chemical_formula_moiety         'C20 H18 N4'
_chemical_formula_sum            'C20 H18 N4'
_chemical_formula_weight         314.38
_chemical_melting_point          216
_chemical_name_common            2,2',3,3'-tetramethyl-6,6'-biquinoxaline
_chemical_name_systematic
;
2,2',3,3'-tetramethyl-6,6'-biquinoxaline
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 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                 93.966(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   12.0225(6)
_cell_length_b                   6.7301(3)
_cell_length_c                   19.1118(10)
_cell_measurement_temperature    100(2)
_cell_volume                     1542.68(13)
_computing_cell_refinement       'SAINT-Plus (Bruker, 2004)'
_computing_data_collection       'APEX2 (Bruker, 2004)'
_computing_data_reduction        SAINT-Plus
_computing_molecular_graphics    'ORTEP-3 (Farrugia, 1997)'
_computing_publication_material  SHELXL97
_computing_structure_refinement  'XSHELL (Bruker, 2004)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.98
_diffrn_measured_fraction_theta_max 0.98
_diffrn_measurement_device_type  'Bruker SMART APEX-II CCD'
_diffrn_measurement_method       '\w and \f'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0495
_diffrn_reflns_av_sigmaI/netI    0.0724
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            8311
_diffrn_reflns_theta_full        68.99
_diffrn_reflns_theta_max         68.99
_diffrn_reflns_theta_min         4.64
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.649
_exptl_absorpt_correction_T_max  0.98
_exptl_absorpt_correction_T_min  0.91
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 2004)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.354
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             664
_exptl_crystal_size_max          0.15
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.190
_refine_diff_density_min         -0.196
_refine_ls_extinction_coef       0.0010(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL97
_refine_ls_goodness_of_fit_ref   1.040
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     146
_refine_ls_number_reflns         1410
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.040
_refine_ls_R_factor_all          0.0496
_refine_ls_R_factor_gt           0.0388
_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^)+0.9428P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1011
_refine_ls_wR_factor_ref         0.1110
_reflns_number_gt                1148
_reflns_number_total             1410
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            bg2005.cif
_cod_data_source_block           I
_cod_original_sg_symbol_Hall     ' -C 2yc'
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               2210491
_cod_database_fobs_code          2210491