A new class of laser dyes, 2-oxa-bicyclo[3.3.0]octa-4,8-diene-3,6-diones, with unity fluorescence yield
Wang, Chao-Yu; Yeh, Yu-Shan; Li, Elise Y.; Liu, Yi-Hong; Peng, Shiuh-Ming; Liu, Shiuh-Tzung; Chou, Pi-Tai; Chemical Communications (Cambridge, United Kingdom)  (2006) 2693–2695; doi:10.1039/b604539a

data_7101240
_publ_section_title
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 A new class of laser dyes, 2-oxa-bicyclo[3.3.0]octa-4,8-diene-3,6-diones,
 with unity fluorescence yield
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_journal_coden_ASTM              CHCOFS
_journal_issue                   25
_journal_name_full
;
 Chemical Communications (Cambridge, United Kingdom)
;
_journal_page_first              2693
_journal_page_last               2695
_journal_paper_doi               10.1039/b604539a
_journal_year                    2006
_chemical_formula_sum            'C19 H12 O3'
_chemical_formula_weight         288.29
_space_group_IT_number           29
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2ac'
_symmetry_space_group_name_H-M   'P c a 21'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   11.7937(4)
_cell_length_b                   12.9224(5)
_cell_length_c                   18.4121(6)
_cell_measurement_reflns_used    22828
_cell_measurement_temperature    295(2)
_cell_measurement_theta_max      25
_cell_measurement_theta_min      1
_cell_volume                     2806.06(17)
_computing_cell_refinement       'HKL Denzo & Scalepack (Otwinowski & Minor)'
_computing_data_collection       'COLLECT (Nonius BV)'
_computing_data_reduction        'HKL Denzo & Scalepack (Otwinowski & Minor)'
_computing_molecular_graphics    SHELXTL
_computing_publication_material  SHELXTL
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      295(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'Nonius KappaCCD'
_diffrn_measurement_method       CCD
_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  0.1298
_diffrn_reflns_av_sigmaI/netI    0.0871
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            12826
_diffrn_reflns_theta_full        25.01
_diffrn_reflns_theta_max         25.01
_diffrn_reflns_theta_min         2.21
_exptl_absorpt_coefficient_mu    0.092
_exptl_absorpt_correction_T_max  0.989
_exptl_absorpt_correction_T_min  0.938
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
multi-scan from symmetry-related measurements
Sortav (Blessing 1995)
;
_exptl_crystal_colour            pale
_exptl_crystal_density_diffrn    1.365
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             1200
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.379
_refine_diff_density_min         -0.457
_refine_diff_density_rms         0.142
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0(10)
_refine_ls_extinction_coef       0.181(15)
_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   1.039
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     398
_refine_ls_number_reflns         2533
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.039
_refine_ls_R_factor_all          0.1092
_refine_ls_R_factor_gt           0.0692
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1065P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1411
_refine_ls_wR_factor_ref         0.1765
_reflns_number_gt                1676
_reflns_number_total             2533
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b604539a.txt
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Orthorhombic' changed to 'orthorhombic'
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_sg_symbol_H-M      Pca2(1)
_cod_database_code               7101240