Relations between 77Se NMR chemical shifts of (phenylseleno)benzenes and their molecular structures derived from nine X-ray crystal structures
Oddershede, Jette; Henriksen, Lars; Larsen, Sine; Organic & Biomolecular Chemistry 1 (2003) 1053–; doi:10.1039/b211130f

data_7150471
_publ_section_title
;
 Relations between 77Se NMR chemical shifts of (phenylseleno)benzenes
 and their molecular structures derived from nine X-ray crystal
 structures
;
_journal_issue                   6
_journal_name_full               'Organic &amp;  Biomolecular Chemistry'
_journal_page_first              1053
_journal_paper_doi               10.1039/b211130f
_journal_volume                  1
_journal_year                    2003
_chemical_formula_moiety         'C20 H18 O2 Se2'
_chemical_formula_sum            'C20 H18 O2 Se2'
_chemical_formula_weight         448.26
_chemical_name_common            5
_chemical_name_systematic
; 
1,4-dimethoxy-2,5-bis(phenylseleno)benzene 
;
_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           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 103.609(11)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   7.1618(10)
_cell_length_b                   15.1320(19)
_cell_length_c                   8.2912(10)
_cell_measurement_reflns_used    20
_cell_measurement_temperature    122.0(5)
_cell_measurement_theta_max      42.38
_cell_measurement_theta_min      39.52
_cell_volume                     873.3(2)
_computing_cell_refinement       'CAD4 Express (1994)'
_computing_data_collection       'CAD4 Express (1994)'
_computing_data_reduction        'DREADD (Blessing 1987)'
_computing_molecular_graphics    'ORTEPII (Johnson, 1976)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      122.0(5)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Enraf-Nonius CAD4'
_diffrn_measurement_method       \w--2\q
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54180
_diffrn_reflns_av_R_equivalents  0.0451
_diffrn_reflns_av_sigmaI/netI    0.0334
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            4116
_diffrn_reflns_theta_full        74.93
_diffrn_reflns_theta_max         74.93
_diffrn_reflns_theta_min         5.85
_diffrn_standards_decay_%        4.0
_diffrn_standards_interval_time  167
_diffrn_standards_number         5
_exptl_absorpt_coefficient_mu    5.363
_exptl_absorpt_correction_T_max  0.208
_exptl_absorpt_correction_T_min  0.046
_exptl_absorpt_correction_type   integration
_exptl_absorpt_process_details   '(DeTitta, 1985)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.705
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       'thin plate'
_exptl_crystal_F_000             444
_exptl_crystal_size_max          0.24
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.713
_refine_diff_density_min         -1.179
_refine_diff_density_rms         0.125
_refine_ls_extinction_coef       0.0082(7)
_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   1.104
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     111
_refine_ls_number_reflns         1797
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.104
_refine_ls_R_factor_all          0.0352
_refine_ls_R_factor_gt           0.0346
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0603P)^2^+0.7230P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0958
_refine_ls_wR_factor_ref         0.0965
_reflns_number_gt                1748
_reflns_number_total             1797
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b211130f.txt
_cod_data_source_block           5
_cod_original_cell_volume        873.31(19)
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               7150471