A synchrotron diffraction study of two polymorphic forms of 2,5-bis[2-(4-methoxyphenyl)ethenyl]pyrazine
Scaccianoce, Laura; Feeder, Neil; Teat, Simon J.; Marseglia, Elisabeth A.; Grimsdale, Andrew C.; Holmes, Andrew B.; Acta Crystallographica Section C 56 (2000) 1277–1279; doi:10.1107/S0108270100010337

data_2011402
_publ_section_title
;
 A synchrotron diffraction study of two polymorphic forms of
 2,5-bis[2-(4-methoxyphenyl)ethenyl]pyrazine
;
_journal_issue                   10
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              1277
_journal_page_last               1279
_journal_paper_doi               10.1107/S0108270100010337
_journal_volume                  56
_journal_year                    2000
_chemical_formula_moiety         'C22 H20 N2 O2'
_chemical_formula_sum            'C22 H20 N2 O2'
_chemical_formula_weight         344.40
_chemical_name_common            2,5-bis[2-(4-methoxyphenyl)ethenyl]pyrazine
_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'
_cell_angle_alpha                90.00
_cell_angle_beta                 102.815(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   32.339(6)
_cell_length_b                   5.7320(10)
_cell_length_c                   9.411(2)
_cell_measurement_reflns_used    4261
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      29.33
_cell_measurement_theta_min      3.64
_cell_volume                     1701.0(6)
_computing_cell_refinement       'LSCELL (Clegg, 1995)'
_computing_data_collection       'SMART (Bruker, 1998)'
_computing_data_reduction        'SAINT (Bruker, 1997)'
_computing_molecular_graphics    'SCHAKAL97 (Keller, 1997)'
_computing_publication_material  'SHELXL97 and PLATON (Spek, 1990)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      150(2)
_diffrn_detector_area_resol_mean 8.192
_diffrn_measured_fraction_theta_full .922
_diffrn_measured_fraction_theta_max .922
_diffrn_measurement_device_type  'Bruker SMART CCD'
_diffrn_measurement_method       'thin slice, \w-scans'
_diffrn_radiation_monochromator  'Silicon 111'
_diffrn_radiation_source
'Daresbury SRS, Station 9.8 (Greaves et al., 1997; Clegg et al., 1998)'
_diffrn_radiation_type           synchrotron
_diffrn_radiation_wavelength     .68910
_diffrn_reflns_av_R_equivalents  .032
_diffrn_reflns_av_sigmaI/netI    .040
_diffrn_reflns_limit_h_max       45
_diffrn_reflns_limit_h_min       -43
_diffrn_reflns_limit_k_max       5
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            5705
_diffrn_reflns_theta_full        29.43
_diffrn_reflns_theta_max         29.43
_diffrn_reflns_theta_min         2.50
_exptl_absorpt_coefficient_mu    .087
_exptl_absorpt_correction_T_max  .991
_exptl_absorpt_correction_T_min  .988
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 1997)'
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.345
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             728
_exptl_crystal_size_max          .14
_exptl_crystal_size_mid          .12
_exptl_crystal_size_min          .10
_refine_diff_density_max         .38
_refine_diff_density_min         -.20
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.089
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     119
_refine_ls_number_reflns         2384
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.089
_refine_ls_R_factor_all          .064
_refine_ls_R_factor_gt           .049
_refine_ls_shift/su_max          .009
_refine_ls_shift/su_mean         .003
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w = 1/[\s^2^(Fo^2^)+(0.0801P)^2^+0.6111P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         .141
_reflns_number_gt                1937
_reflns_number_total             2384
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            bm1420.cif
_cod_data_source_block           g-form
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from
2010-06-29.

'_geom_bond_publ_flag' value 'No' changed to 'no' according
to '/home/saulius/struct/CIF-dictionaries/cif_core.dic' dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29 (25 times).

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 

The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from
2010-06-29.

'_geom_bond_publ_flag' value 'No' changed to 'no'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29 (25
times).

'_geom_angle_publ_flag' value 'No' changed to 'no' according
to /home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary
named 'cif_core.dic' version 2.4.1 from 2010-06-29 (38
times).

'_geom_torsion_publ_flag' value 'No' changed to 'no'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29 (20
times).

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               2011402
_cod_database_fobs_code          2011402