Solution, solid state structure and fluorescence studies of 2,3-functionalized quinoxalines: evidence for a π-delocalized keto-enamine form with N‒H···O intramolecular hydrogen bonds
Touzani, Rachid; Ben-Hadda, Taibi; Elkadiri, Sghir; Ramdani, Abdelkrim; Maury, Olivier; Le Bozec, Hubert; Toupet, Loic; Dixneuf, Pierre H.; New Journal of Chemistry 25 (2001) 391–; doi:10.1039/b009667i

data_7051092
_publ_section_title
;
 Solution, solid state structure and fluorescence studies of
 2,3-functionalized quinoxalines: evidence for a \p-delocalized
 keto-enamine form with N--H&#x00B7;&#x00B7;&#x00B7;O intramolecular
 hydrogen bonds
;
_journal_issue                   3
_journal_name_full               'New Journal of Chemistry'
_journal_page_first              391
_journal_paper_doi               10.1039/b009667i
_journal_volume                  25
_journal_year                    2001
_chemical_formula_sum            'C48 H48 N4 O4'
_chemical_formula_weight         744.90
_chemical_name_systematic
;

 ?

;
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 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                 109.91(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   11.008(3)
_cell_length_b                   18.305(3)
_cell_length_c                   10.524(6)
_cell_measurement_temperature    293(2)
_cell_volume                     1993.9(14)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0414
_diffrn_reflns_av_sigmaI/netI    0.1269
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       23
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            4711
_diffrn_reflns_theta_full        26.98
_diffrn_reflns_theta_max         26.98
_diffrn_reflns_theta_min         2.06
_exptl_absorpt_coefficient_mu    0.079
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.241
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             792
_exptl_crystal_size_max          0.35
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.28
_refine_diff_density_max         0.143
_refine_diff_density_min         -0.149
_refine_diff_density_rms         0.034
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0(3)
_refine_ls_extinction_coef       0.0028(10)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   0.905
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     518
_refine_ls_number_reflns         4483
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.905
_refine_ls_R_factor_all          0.2081
_refine_ls_R_factor_gt           0.0511
_refine_ls_shift/su_max          0.009
_refine_ls_shift/su_mean         0.002
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0643P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1040
_refine_ls_wR_factor_ref         0.1465
_reflns_number_gt                1794
_reflns_number_total             4483
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b009667i.txt
_cod_data_source_block           tr29rr
_cod_depositor_comments
;
The following automatic conversions were performed:
'_atom_site_symetry_multiplicity' tag replaced with
'_atom_site_symmetry_multiplicity'.

Automatic conversion script
Id: cif_correct_tags 1440 2010-10-19 06:21:57Z 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.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 
;
_cod_original_cell_volume        1993.8(13)
_cod_original_sg_symbol_H-M      P21
_cod_database_code               7051092