Imidazo[1,5-a]pyridine: A Versatile Architecture for Stable N-Heterocyclic Carbenes
Manuel Alcarazo; Stephen J. Roseblade; Andrew R. Cowley; Rosario Fernández; John M. Brown; José M. Lassaletta; Journal of the American Chemical Society 127 (2005) 3290–3291; doi:10.1021/ja0423769

data_4111498
_publ_section_title
;
 Imidazo[1,5-a]pyridine: A Versatile Architecture for Stable
 N-Heterocyclic Carbenes
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              3290
_journal_page_last               3291
_journal_paper_doi               10.1021/ja0423769
_journal_volume                  127
_journal_year                    2005
_chemical_compound_source
;
?
;
_chemical_formula_moiety         ' C23 H26 Br0.159 Cl0.841 N2 Rh '
_chemical_formula_sum            'C23 H26 Br0.159 Cl0.841 N2 Rh'
_chemical_formula_weight         475.89
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_cell_angle_alpha                90
_cell_angle_beta                 98.3820(11)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   13.4068(3)
_cell_length_b                   17.5452(3)
_cell_length_c                   17.0553(3)
_cell_measurement_reflns_used    21225
_cell_measurement_temperature    150
_cell_measurement_theta_max      28
_cell_measurement_theta_min      5
_cell_volume                     3968.98(13)
_computing_cell_refinement
; 
KappaCCD software 'DENZO' (Otwinowski & Minor, 1996) 
;
_computing_data_collection
; 
KappaCCD software 'Collect' (Nonius, 2000) 
;
_computing_data_reduction
; 
KappaCCD software 'DENZO' (Otwinowski & Minor, 1996) 
;
_computing_publication_material
; 
CRYSTALS (Watkin et al, 2001) 
;
_computing_structure_refinement
; 
CRYSTALS (Watkin et al, 2001) 
;
_computing_structure_solution    'SIR92 (Giacovazzo et al, 1992)'
_diffrn_ambient_temperature      150
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type
; 
Nonius KappaCCD 
;
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.052
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -17
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       -22
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            21225
_diffrn_reflns_theta_full        27.469
_diffrn_reflns_theta_max         27.469
_diffrn_reflns_theta_min         5.102
_diffrn_standards_decay_%        0.00
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    1.304
_exptl_absorpt_correction_T_max  0.90
_exptl_absorpt_correction_T_min  0.73
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
; 
 Denzo/Scalepack (Otwinowski & Minor, 1996) 
;
_exptl_crystal_colour            ' yellow '
_exptl_crystal_density_diffrn    1.593
_exptl_crystal_description       ' prism '
_exptl_crystal_F_000             1942.867
_exptl_crystal_size_max          0.24
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.38
_refine_diff_density_min         -0.59
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.1101
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     282
_refine_ls_number_reflns         3180
_refine_ls_number_restraints     8
_refine_ls_R_factor_all          0.0498
_refine_ls_R_factor_gt           0.0285
_refine_ls_shift/su_max          0.013457
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details
;
 Method, part 1, Chebychev polynomial, (Watkin, 1994, Prince, 1982) 
 [weight] = 1.0/[A~0~*T~0~(x)+A~1~*T~1~(x) ... +A~n-1~]*T~n-1~(x)] 
 where A~i~ are the Chebychev coefficients listed below and x= Fcalc/Fmax 
 Method = Robust Weighting (Prince, 1982) 
 W = [weight] * [1-(deltaF/6*sigmaF)^2^]^2^ 
 A~i~ are: 
 0.235 0.837E-01 0.590E-01 
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0523
_refine_ls_wR_factor_gt          0.0314
_refine_ls_wR_factor_ref         0.0314
_reflns_limit_h_max              17
_reflns_limit_h_min              -17
_reflns_limit_k_max              22
_reflns_limit_k_min              0
_reflns_limit_l_max              22
_reflns_limit_l_min              0
_reflns_number_gt                3180
_reflns_number_total             4523
_reflns_threshold_expression     I>3.00u(I)
_cod_data_source_file            ja0423769si20041219_020727.cif
_cod_data_source_block           6b
_cod_original_sg_symbol_H-M      'C 1 2/c 1 '
_cod_original_formula_sum        ' C23 H26 Br0.159 Cl0.841 N2 Rh '
_cod_database_code               4111498