Tris[(1-isopropylbenzimidazol-2-yl)dimethylsilyl]methyl metal complexes, [TismPriBenz]M: a new class of metallacarbatranes, isomerization to a tris(N-heterocyclic carbene) derivative, and evidence for an inverted ligand field
Ruccolo, Serge; Rauch, Michael; Parkin, Gerard; Chem. Sci.  (2017) –; doi:10.1039/C7SC00499K

data_1545911
_publ_section_title
;
 Tris[(1-isopropylbenzimidazol-2-yl)dimethylsilyl]methyl metal complexes,
 [TismPriBenz]M: a new class of metallacarbatranes, isomerization to a
 tris(N-heterocyclic carbene) derivative, and evidence for an inverted
 ligand field
;
_journal_name_full               'Chem. Sci.'
_journal_paper_doi               10.1039/C7SC00499K
_journal_year                    2017
_chemical_formula_sum            'C37 H51 Li N6 Si3'
_chemical_formula_weight         671.04
_space_group_crystal_system      cubic
_space_group_IT_number           197
_space_group_name_Hall           'I 2 2 3'
_space_group_name_H-M_alt        'I 2 3'
_symmetry_space_group_name_Hall  'I 2 2 3'
_symmetry_space_group_name_H-M   'I 2 3'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2017-01-25 deposited with the CCDC.
2017-03-29 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   20.191(2)
_cell_length_b                   20.191(2)
_cell_length_c                   20.191(2)
_cell_measurement_reflns_used    9784
_cell_measurement_temperature    130(2)
_cell_measurement_theta_max      29.73
_cell_measurement_theta_min      2.47
_cell_volume                     8231.4(14)
_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      130(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_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  0.0576
_diffrn_reflns_av_unetI/netI     0.0225
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       28
_diffrn_reflns_limit_h_min       -28
_diffrn_reflns_limit_k_max       28
_diffrn_reflns_limit_k_min       -28
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            65610
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 1.000
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         30.509
_diffrn_reflns_theta_min         1.426
_exptl_absorpt_coefficient_mu    0.146
_exptl_absorpt_correction_T_max  0.7461
_exptl_absorpt_correction_T_min  0.6996
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.083
_exptl_crystal_description       cube
_exptl_crystal_F_000             2880
_exptl_crystal_size_max          0.260
_exptl_crystal_size_mid          0.230
_exptl_crystal_size_min          0.230
_refine_diff_density_max         0.377
_refine_diff_density_min         -0.184
_refine_diff_density_rms         0.056
_refine_ls_abs_structure_details
; 
 Flack x determined using 1521 quotients [(I+)-(I-)]/[(I+)+(I-)] 
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259). 
;
_refine_ls_abs_structure_Flack   -0.05(4)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.953
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     146
_refine_ls_number_reflns         4198
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.953
_refine_ls_R_factor_all          0.0558
_refine_ls_R_factor_gt           0.0438
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0855P)^2^+4.2121P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1164
_refine_ls_wR_factor_ref         0.1285
_reflns_Friedel_coverage         0.855
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     1.000
_reflns_number_gt                3609
_reflns_number_total             4198
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c7sc00499k2.cif
_cod_data_source_block           mrlis10_sq
_cod_original_cell_volume        8231(3)
_cod_database_code               1545911
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.963
_shelx_estimated_absorpt_t_max   0.967
_shelx_res_checksum              17971
_shelx_fab_checksum              78275