A tropylium annulated N-heterocyclic carbene.
Appel, Sebastian; Brüggemann, Peter; Ganter, Christian; Chemical communications (Cambridge, England) 56 (2020) 9020–9023; doi:10.1039/d0cc04482b

data_7126798
_publ_section_title
;
 A tropylium annulated N-heterocyclic carbene.
;
_journal_issue                   63
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              9020
_journal_page_last               9023
_journal_paper_doi               10.1039/d0cc04482b
_journal_volume                  56
_journal_year                    2020
_chemical_formula_sum            'C6 H6 N2 O2'
_chemical_formula_weight         138.13
_chemical_name_systematic        1-methyl-1H-imidazole-4,5-dicarbaldehyde
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2020-03-20 deposited with the CCDC.	2020-07-01 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   3.8712(16)
_cell_length_b                   6.840(3)
_cell_length_c                   23.770(9)
_cell_measurement_reflns_used    1648
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      28.195
_cell_measurement_theta_min      3.099
_cell_volume                     629.4(4)
_computing_cell_refinement       'SAINT (Bruker, 2015)'
_computing_data_collection       'APEX2 (Bruker, 2014)'
_computing_data_reduction        'SAINT (Bruker, 2015)'
_computing_molecular_graphics    'DIAMOND 3.2 (Crystal Impact, 2015)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXL-2014 (Sheldrick, 2014)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker Kappa APEX-II CCD area detector'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  'multilayer mirror'
_diffrn_radiation_source         'microfocus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0255
_diffrn_reflns_av_unetI/netI     0.0289
_diffrn_reflns_Laue_measured_fraction_full 0.997
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -5
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            3988
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.997
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.319
_diffrn_reflns_theta_min         1.713
_exptl_absorpt_coefficient_mu    0.112
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.8519
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(<i>SADABS</i>; Sheldrick, 2015)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.458
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             288
_exptl_crystal_size_max          0.4
_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.1
_refine_diff_density_max         0.178
_refine_diff_density_min         -0.209
_refine_diff_density_rms         0.045
_refine_ls_abs_structure_details
;
 Flack x determined using 489 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.8(7)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.114
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     92
_refine_ls_number_reflns         1563
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.114
_refine_ls_R_factor_all          0.0479
_refine_ls_R_factor_gt           0.0416
_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^)+(0.0529P)^2^+0.0751P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1037
_refine_ls_wR_factor_ref         0.1071
_reflns_Friedel_coverage         0.616
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                1405
_reflns_number_total             1563
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d0cc04482b2.cif
_cod_data_source_block           mo_scan_0m
_cod_depositor_comments
'Adding full bibliography for 7126798--7126803.cif.'
_cod_database_code               7126798
_shelx_shelxl_version_number     2014/7
_shelx_res_checksum              54473
_shelx_hkl_checksum              37433