Twisting the arm: structural constraints in bicyclic expanded-ring N-heterocyclic carbenes.
Sampford, Katharine R.; Carden, Jamie L.; Kidner, Edward B.; Berry, Abigail; Cavell, Kingsley J.; Murphy, Damien M.; Kariuki, Benson M.; Newman, Paul D.; Dalton transactions (Cambridge, England : 2003) 48 (2019) 1850–1858; doi:10.1039/c8dt04462g

data_7048669
_publ_section_title
;
 Twisting the arm: structural constraints in bicyclic expanded-ring
 N-heterocyclic carbenes.
;
_journal_issue                   5
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              1850
_journal_page_last               1858
_journal_paper_doi               10.1039/c8dt04462g
_journal_volume                  48
_journal_year                    2019
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C38 H56 Au2 I2 N4'
_chemical_formula_sum            'C38 H56 Au2 I2 N4'
_chemical_formula_weight         1216.60
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2018/1
_audit_update_record
;
2018-12-10 deposited with the CCDC.
2018-12-11 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 97.576(2)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   7.9564(2)
_cell_length_b                   19.0099(4)
_cell_length_c                   13.4208(3)
_cell_measurement_reflns_used    10470
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      28.9520
_cell_measurement_theta_min      3.2130
_cell_volume                     2012.18(8)
_computing_cell_refinement       'CrysAlisPro 1.171.38.43f (Rigaku OD, 2015)'
_computing_data_collection       'CrysAlisPro 1.171.38.43f (Rigaku OD, 2015)'
_computing_data_reduction        'CrysAlisPro 1.171.38.43f (Rigaku OD, 2015)'
_computing_molecular_graphics    ORTEP-3
_computing_publication_material  WinGX
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_computing_structure_solution    'SHELXL-2013 (Sheldrick, 2013)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.885
_diffrn_measurement_device_type  'SuperNova, Dual, Cu at zero, Atlas'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0295
_diffrn_reflns_av_unetI/netI     0.0451
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.885
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       26
_diffrn_reflns_limit_k_min       -26
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            20186
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.834
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         29.708
_diffrn_reflns_theta_min         3.020
_exptl_absorpt_coefficient_mu    8.847
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.532
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.38.43f (Rigaku Oxford Diffraction, 2015)
Numerical absorption correction based on gaussian integration over
            a multifaceted crystal model
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    2.008
_exptl_crystal_description       block
_exptl_crystal_F_000             1152
_exptl_crystal_size_max          0.263
_exptl_crystal_size_mid          0.186
_exptl_crystal_size_min          0.152
_refine_diff_density_max         1.225
_refine_diff_density_min         -1.559
_refine_diff_density_rms         0.143
_refine_ls_abs_structure_details
;
 Flack x determined using 3723 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.001(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.045
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     429
_refine_ls_number_reflns         9523
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.045
_refine_ls_R_factor_all          0.0369
_refine_ls_R_factor_gt           0.0324
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0308P)^2^+1.3833P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0683
_refine_ls_wR_factor_ref         0.0709
_reflns_Friedel_coverage         0.833
_reflns_Friedel_fraction_full    0.999
_reflns_Friedel_fraction_max     0.780
_reflns_number_gt                8835
_reflns_number_total             9523
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c8dt04462g2.cif
_cod_data_source_block           pdn1704
_cod_depositor_comments
'Adding full bibliography for 7048655--7048669.cif.'
_cod_database_code               7048669
_shelx_shelxl_version_number     2018/1
_shelx_estimated_absorpt_t_min   0.204
_shelx_estimated_absorpt_t_max   0.347
_shelx_res_checksum              70018