Tetrakis(trialkylsilylethynylphenyl)ethenes: mechanofluorochromism arising from steric considerations with an unusual crystal structure
Ramachandran, Elumalai; Dhamodharan, Raghavachari; J. Mater. Chem. C 5 (2017) 10469–; doi:10.1039/C7TC03211K

data_7236893
_publ_section_title
;
 Tetrakis(trialkylsilylethynylphenyl)ethenes: mechanofluorochromism
 arising from steric considerations with an unusual crystal structure
;
_journal_issue                   40
_journal_name_full               'J. Mater. Chem. C'
_journal_page_first              10469
_journal_paper_doi               10.1039/C7TC03211K
_journal_volume                  5
_journal_year                    2017
_chemical_formula_moiety         C46H52Si4
_chemical_formula_sum            'C46 H52 Si4'
_chemical_formula_weight         717.24
_chemical_name_systematic
1,1,2,2-tetrakis(4-((trimethylsilyl)ethynyl)phenyl)ethene
_space_group_crystal_system      orthorhombic
_space_group_IT_number           45
_space_group_name_Hall           'I 2 -2c'
_space_group_name_H-M_alt        'I b a 2'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2017-06-08 deposited with the CCDC.
2017-09-29 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   15.856(4)
_cell_length_b                   28.435(7)
_cell_length_c                   10.3986(19)
_cell_measurement_reflns_used    1772
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      20.04
_cell_measurement_theta_min      2.50
_cell_volume                     4688.4(19)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick 2008)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0703
_diffrn_reflns_av_unetI/netI     0.0806
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       18
_diffrn_reflns_limit_h_min       -18
_diffrn_reflns_limit_k_max       26
_diffrn_reflns_limit_k_min       -33
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            15687
_diffrn_reflns_point_group_measured_fraction_full 0.993
_diffrn_reflns_point_group_measured_fraction_max 0.993
_diffrn_reflns_theta_full        24.995
_diffrn_reflns_theta_max         24.995
_diffrn_reflns_theta_min         2.504
_exptl_absorpt_coefficient_mu    0.154
_exptl_absorpt_correction_T_max  0.980
_exptl_absorpt_correction_T_min  0.963
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS V2014/5(Bruker AXS.Inc)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.016
_exptl_crystal_description       Rectangular
_exptl_crystal_F_000             1536
_exptl_crystal_preparation       ', Luminescent'
_exptl_crystal_size_max          0.250
_exptl_crystal_size_mid          0.220
_exptl_crystal_size_min          0.130
_refine_diff_density_max         0.146
_refine_diff_density_min         -0.152
_refine_diff_density_rms         0.032
_refine_ls_abs_structure_details
; 
 Flack x determined using 752 quotients [(I+)-(I-)]/[(I+)+(I-)] 
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259). 
;
_refine_ls_abs_structure_Flack   0.01(10)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.990
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     232
_refine_ls_number_reflns         4109
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.990
_refine_ls_R_factor_all          0.1168
_refine_ls_R_factor_gt           0.0493
_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^)+(0.0470P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0939
_refine_ls_wR_factor_ref         0.1161
_reflns_Friedel_coverage         0.870
_reflns_Friedel_fraction_full    0.987
_reflns_Friedel_fraction_max     0.987
_reflns_number_gt                2283
_reflns_number_total             4109
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c7tc03211k2.cif
_cod_data_source_block           tpet
_cod_original_cell_volume        4688.3(18)
_cod_database_code               7236893
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.963
_shelx_estimated_absorpt_t_max   0.980
_shelx_res_checksum              37520