A fluorenylidene-acridane that becomes dark in color upon grinding - ground state mechanochromism by conformational change.
Suzuki, Tsuyoshi; Okada, Hiroshi; Nakagawa, Takafumi; Komatsu, Kazuki; Fujimoto, Chikako; Kagi, Hiroyuki; Matsuo, Yutaka; Chemical science 9 (2018) 475–482; doi:10.1039/c7sc03567e

data_1548054
_publ_section_title
;
 A fluorenylidene-acridane that becomes dark in color upon grinding -
 ground state mechanochromism by conformational change.
;
_journal_issue                   2
_journal_name_full               'Chemical science'
_journal_page_first              475
_journal_page_last               482
_journal_paper_doi               10.1039/c7sc03567e
_journal_volume                  9
_journal_year                    2018
_chemical_formula_sum            'C27 H19 N'
_chemical_formula_weight         357.43
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yab'
_space_group_name_H-M_alt        'P 1 21/a 1'
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yab'
_symmetry_space_group_name_H-M   'P 1 21/a 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_audit_update_record
;
2016-03-04 deposited with the CCDC.
2017-10-24 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 111.14(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.379(6)
_cell_length_b                   22.716(16)
_cell_length_c                   9.381(7)
_cell_measurement_reflns_used    1729
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      23.24
_cell_measurement_theta_min      2.33
_cell_volume                     1466.6(19)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.297
_diffrn_measured_fraction_theta_max 0.297
_diffrn_measurement_device_type  'Image plate'
_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  0.0457
_diffrn_reflns_av_sigmaI/netI    0.0419
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       24
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -7
_diffrn_reflns_number            1093
_diffrn_reflns_theta_full        23.22
_diffrn_reflns_theta_max         23.24
_diffrn_reflns_theta_min         2.33
_exptl_absorpt_coefficient_mu    0.093
_exptl_crystal_density_diffrn    1.619
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       platelet
_exptl_crystal_F_000             752
_refine_diff_density_max         0.340
_refine_diff_density_min         -0.339
_refine_diff_density_rms         0.094
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.838
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     254
_refine_ls_number_reflns         623
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.838
_refine_ls_R_factor_all          0.1219
_refine_ls_R_factor_gt           0.1217
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.2000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.3147
_refine_ls_wR_factor_ref         0.3149
_reflns_number_gt                621
_reflns_number_total             623
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c7sc03567e3.cif
_cod_data_source_block           mefa_p
_cod_depositor_comments
'Adding full bibliography for 1548053--1548056.cif.'
_cod_original_cell_volume        1466.51(10)
_cod_original_sg_symbol_H-M      'P 21/a'
_cod_database_code               1548054