Structure of three novel photochromic compounds; X-ray crystallographic and theoretical studies
Crano, J.; Knowles, D.; Kwiatkowski, P.; Flood, T.; Ross, R.; Chiang, L.; Lasch, J.; Chadha, R.; Siuzdak, G.; Acta Crystallographica Section B 50 (1994) 772–779; doi:10.1107/S0108768194005938

data_2101245
_publ_section_title
;
 Structure of three novel photochromic compounds; X-ray
 crystallographic and theoretical studies
;
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              772
_journal_page_last               779
_journal_paper_doi               10.1107/S0108768194005938
_journal_volume                  50
_journal_year                    1994
_chemical_formula_sum            'C20 H22 N2 O3'
_chemical_formula_weight         338.4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_type_scat_source           IntTabIV
_cell_angle_alpha                90
_cell_angle_beta                 90.310(10)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   12.151(2)
_cell_length_b                   12.090(4)
_cell_length_c                   24.836(4)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    296
_cell_measurement_theta_max      40
_cell_measurement_theta_min      25
_cell_volume                     3648.5(15)
_diffrn_measurement_device       'Rigaku AFC-6R four-circle'
_diffrn_measurement_method       2\q-\q
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0239
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            6159
_diffrn_reflns_theta_max         60.0
_diffrn_standards_decay_%        'not significant'
_diffrn_standards_interval_count 200
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.637
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.23
_exptl_crystal_description       parallelepiped
_exptl_crystal_size_max          0.31
_exptl_crystal_size_mid          0.23
_exptl_crystal_size_min          0.14
_refine_diff_density_max         0.58
_refine_diff_density_min         -0.30
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_obs   2.43
_refine_ls_hydrogen_treatment    noref
_refine_ls_number_parameters     451
_refine_ls_number_reflns         3106
_refine_ls_R_factor_obs          0.0630
_refine_ls_shift/esd_max         0.018
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     'w = 1/[\s^2^(F)+0.0004F^2^]'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_obs         0.0794
_reflns_number_observed          3106
_reflns_number_total             5446
_reflns_observed_criterion       F>4.0\s(F)
_cod_data_source_file            st1087.cif
_cod_data_source_block           st1087a
_cod_depositor_comments
;
The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value '1/[\s^2^(F)+0.0004F^2^]' was
changed to 'calc'. New tag '_refine_ls_weighting_details' was
created. The value of the new tag was set to 'w =
1/[\s^2^(F)+0.0004F^2^]'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        3648(2)
_cod_database_code               2101245