Selectivity in the Photodimerization of 6-Alkylcoumarins
Xiuling Yu; Dieter Scheller; Otto Rademacher; Thomas Wolff; Journal of Organic Chemistry 68 (2003) 7386–7399; doi:10.1021/jo034627m

data_4022487
_publ_section_title
;
 Selectivity in the Photodimerization of 6-Alkylcoumarins
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              7386
_journal_page_last               7399
_journal_paper_doi               10.1021/jo034627m
_journal_volume                  68
_journal_year                    2003
_chemical_formula_sum            'C20 H16 O4'
_chemical_formula_weight         320.33
_chemical_melting_point          536
_chemical_name_systematic
;
     rel-(6aR, 6bS, 12bS,12cR)-2,11-Dimethyl-6a,6b,12b,12c-tetrahydro-
     5,8-dioxa-dibenzo[a,i]biphenylene-6,7-dione
;
_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                 97.55
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   22.019(2)
_cell_length_b                   7.1094(10)
_cell_length_c                   19.993(2)
_cell_measurement_temperature    293(2)
_cell_volume                     3102.6(6)
_computing_cell_refinement       'ENRAF NONIUS CAD4'
_computing_data_collection       'ENRAF NONIUS CAD4'
_computing_data_reduction        'ENRAF NONIUS XCAD4PC'
_computing_molecular_graphics    ZORTEP
_computing_publication_material  ZORTEP
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'ENRAF NONIUS CAD4'
_diffrn_measurement_method       'omega - two theta scan'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0924
_diffrn_reflns_av_sigmaI/netI    0.0550
_diffrn_reflns_limit_h_max       26
_diffrn_reflns_limit_h_min       -26
_diffrn_reflns_limit_k_max       0
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            10912
_diffrn_reflns_theta_full        25.06
_diffrn_reflns_theta_max         25.06
_diffrn_reflns_theta_min         1.87
_diffrn_standards_interval_count 400
_diffrn_standards_interval_time  3600
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.095
_exptl_absorpt_correction_T_max  'not corrected'
_exptl_absorpt_correction_T_min  'not corrected'
_exptl_absorpt_correction_type   'not corrected'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.372
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             1344
_exptl_crystal_size_max          0.72
_exptl_crystal_size_mid          0.50
_exptl_crystal_size_min          0.22
_refine_diff_density_max         0.308
_refine_diff_density_min         -0.343
_refine_diff_density_rms         0.088
_refine_ls_extinction_coef       0.0026(4)
_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   1.083
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     282
_refine_ls_number_reflns         2734
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.083
_refine_ls_R_factor_all          0.0647
_refine_ls_R_factor_gt           0.0489
_refine_ls_shift/su_max          0.008
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0626P)^2^+1.6800P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1164
_refine_ls_wR_factor_ref         0.1314
_reflns_number_gt                2238
_reflns_number_total             2734
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo034627msi20030804_041506.cif
_cod_data_source_block           XY
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               4022487