An NHC-Stabilized Silicon Analogue of Acylium Ion: Synthesis, Structure, Reactivity, and Theoretical Studies.
Ahmad, Syed Usman; Szilvási, Tibor; Irran, Elisabeth; Inoue, Shigeyoshi; Journal of the American Chemical Society 137 (2015) 5828–5836; doi:10.1021/jacs.5b01853

data_4129396
_publ_section_title
;
 An NHC-Stabilized Silicon Analogue of Acylium Ion: Synthesis, Structure,
 Reactivity, and Theoretical Studies.
;
_journal_issue                   17
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              5828
_journal_page_last               5836
_journal_paper_doi               10.1021/jacs.5b01853
_journal_volume                  137
_journal_year                    2015
_chemical_formula_moiety         'C48 H50 O4 Si2, 2(C7 H13 N2), 2(C2 H3 N)'
_chemical_formula_sum            'C66 H82 N6 O4 Si2'
_chemical_formula_weight         1079.56
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method
;
CrysAlisPro, Agilent Technologies,
Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET)
(compiled Aug  2 2013,16:46:58)
;
_cell_angle_alpha                90.00
_cell_angle_beta                 96.877(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   12.4980(6)
_cell_length_b                   13.8363(7)
_cell_length_c                   18.2313(8)
_cell_measurement_reflns_used    3400
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      72.9420
_cell_measurement_theta_min      4.0260
_cell_volume                     3130.0(3)
_computing_cell_refinement
;
CrysAlisPro, Agilent Technologies,
Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET)
(compiled Aug  2 2013,16:46:58)
;
_computing_data_collection
;
CrysAlisPro, Agilent Technologies,
Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET)
(compiled Aug  2 2013,16:46:58)
;
_computing_data_reduction
;
CrysAlisPro, Agilent Technologies,
Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET)
(compiled Aug  2 2013,16:46:58)
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'SuperNova, Single source at offset, Atlas'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_source         'SuperNova (Cu) X-ray Source'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0534
_diffrn_reflns_av_sigmaI/netI    0.0666
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            12398
_diffrn_reflns_theta_full        67.49
_diffrn_reflns_theta_max         67.49
_diffrn_reflns_theta_min         4.02
_exptl_absorpt_coefficient_mu    0.906
_exptl_absorpt_correction_T_max  0.8798
_exptl_absorpt_correction_T_min  0.8304
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro, Agilent Technologies,
Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET)
(compiled Aug  2 2013,16:46:58)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.145
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1160
_exptl_crystal_size_max          0.21
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.14
_refine_diff_density_max         0.462
_refine_diff_density_min         -0.500
_refine_diff_density_rms         0.065
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.078
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     388
_refine_ls_number_reflns         5634
_refine_ls_number_restraints     36
_refine_ls_restrained_S_all      1.076
_refine_ls_R_factor_all          0.0960
_refine_ls_R_factor_gt           0.0695
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0785P)^2^+2.1850P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1731
_refine_ls_wR_factor_ref         0.1925
_reflns_number_gt                4080
_reflns_number_total             5634
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja5b01853_si_003.cif
_cod_data_source_block           cu-398
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               4129396