Highly durable photochromic radical complexes having no steric protections of radicals.
Kobayashi, Yoichi; Mishima, Yasuhiro; Mutoh, Katsuya; Abe, Jiro; Chemical communications (Cambridge, England) 53 (2017) 4315–4318; doi:10.1039/c7cc01439b

data_7119867
_publ_section_title
;
 Highly durable photochromic radical complexes having no steric
 protections of radicals.
;
_journal_issue                   31
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              4315
_journal_page_last               4318
_journal_paper_doi               10.1039/c7cc01439b
_journal_volume                  53
_journal_year                    2017
_chemical_formula_sum            'C25 H30 N2 O'
_chemical_formula_weight         374.51
_chemical_name_systematic
3,5-di-tert-butyl-2',3'-dimethylspiro[cyclohexane-1,5'-imidazo[2,1-a]isoindole]-2,5-dien-4-one
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_update_record
;
2017-02-23 deposited with the CCDC.
2017-03-22 downloaded from the CCDC.
;
_cell_angle_alpha                83.1537(13)
_cell_angle_beta                 71.5734(13)
_cell_angle_gamma                86.3277(12)
_cell_formula_units_Z            2
_cell_length_a                   9.2185(9)
_cell_length_b                   9.7237(9)
_cell_length_c                   12.7331(12)
_cell_measurement_reflns_used    2997
_cell_measurement_temperature    296.0
_cell_measurement_theta_max      28.3656
_cell_measurement_theta_min      2.3296
_cell_volume                     1074.71(18)
_computing_cell_refinement       'SAINT V8.32B (Bruker AXS Inc., 2013)'
_computing_data_collection       'Bruker SMART APEXII'
_computing_data_reduction        'SAINT V8.32B (Bruker AXS Inc., 2013)'
_computing_molecular_graphics    'XSHELL V6.3.1 (Bruker AXS)'
_computing_publication_material  'Generate Report (Bruker AXS)'
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_diffrn_ambient_temperature      296.0
_diffrn_detector_area_resol_mean 8.3333
_diffrn_measured_fraction_theta_full 0.986
_diffrn_measured_fraction_theta_max 0.986
_diffrn_measurement_device_type  'Bruker D8 goniometer'
_diffrn_measurement_method       'omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0110
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -5
_diffrn_reflns_number            4405
_diffrn_reflns_theta_full        23.25
_diffrn_reflns_theta_max         23.25
_diffrn_reflns_theta_min         2.84
_diffrn_source                   'sealed tube'
_exptl_absorpt_coefficient_mu    0.070
_exptl_absorpt_correction_T_max  0.99
_exptl_absorpt_correction_T_min  0.90
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   'SADABS Sheldrick 1996'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.157
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             404
_exptl_crystal_recrystallization_method 'Re-crystallisation from solvent'
_exptl_crystal_size_max          0.100
_exptl_crystal_size_mid          0.100
_exptl_crystal_size_min          0.100
_refine_diff_density_max         0.351
_refine_diff_density_min         -0.176
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.020
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     261
_refine_ls_number_reflns         3047
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.020
_refine_ls_R_factor_all          0.0457
_refine_ls_R_factor_gt           0.0403
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0506P)^2^+0.6324P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1017
_refine_ls_wR_factor_ref         0.1060
_reflns_number_gt                2707
_reflns_number_total             3047
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c7cc01439b2.cif
_cod_data_source_block           I
_cod_depositor_comments          'Adding full bibliography for 7119867.cif.'
_cod_database_code               7119867
_shelx_res_checksum              45221
_shelx_hkl_checksum              15828