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_1548056
_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           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 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                90.00
_cell_angle_beta                 90.1024(18)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   7.3384(2)
_cell_length_b                   18.5774(6)
_cell_length_c                   13.3299(4)
_cell_measurement_temperature    123(2)
_cell_volume                     1817.24(9)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      123(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Image plate'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54187
_diffrn_reflns_av_R_equivalents  0.0378
_diffrn_reflns_av_sigmaI/netI    0.0532
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            20326
_diffrn_reflns_theta_full        66.99
_diffrn_reflns_theta_max         66.99
_diffrn_reflns_theta_min         3.32
_exptl_absorpt_coefficient_mu    0.575
_exptl_absorpt_correction_T_max  0.9136
_exptl_absorpt_correction_T_min  0.7778
_exptl_crystal_density_diffrn    1.306
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             752
_exptl_crystal_size_max          0.46
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.16
_refine_diff_density_max         0.396
_refine_diff_density_min         -0.339
_refine_diff_density_rms         0.100
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   1.0(11)
_refine_ls_extinction_coef       0.0072(9)
_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   1.451
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     508
_refine_ls_number_reflns         6277
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.451
_refine_ls_R_factor_all          0.0800
_refine_ls_R_factor_gt           0.0628
_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^)+(0.1000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1697
_refine_ls_wR_factor_ref         0.2075
_reflns_number_gt                5264
_reflns_number_total             6277
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c7sc03567e3.cif
_cod_data_source_block           f2plus
_cod_depositor_comments
'Adding full bibliography for 1548053--1548056.cif.'
_cod_original_sg_symbol_H-M      P21
_cod_database_code               1548056