A Synthetic and Mechanistic Investigation of the Chromium Tricarbonyl-Mediated Masamune‒Bergman Cyclization. Direct Observation of a Ground-State Tripletp-Benzyne Biradical
Ylijoki, Kai E. O.; Lavy, Séverine; Fretzen, Angelika; Kündig, E. Peter; Berclaz, Théo; Bernardinelli, Gérald; Besnard, Céline; Organometallics 31 (2012) 5396–; doi:10.1021/om300427j

data_4078797
_publ_contact_author
;
     E. Peter Kundig
     Department of Organic Chemistry
     University of Geneva
     Quai E. Ansermet 30
     CH - 1211 Geneva 4
     Switzerland
;
_publ_section_title
;
 A Synthetic and Mechanistic Investigation of the Chromium
 Tricarbonyl-Mediated Masamune--Bergman Cyclization. Direct Observation of
 a Ground-State Tripletp-Benzyne Biradical
;
_journal_issue                   15
_journal_name_full               Organometallics
_journal_page_first              5396
_journal_paper_doi               10.1021/om300427j
_journal_volume                  31
_journal_year                    2012
_chemical_formula_moiety         'C18 H25 N O Si , 3(C O), Cr '
_chemical_formula_sum            'C21 H25 Cr N O4 Si'
_chemical_formula_weight         435.52
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_audit_conform_dict_name         cif_core.dic
_audit_conform_dict_version      2.0.1
_audit_creation_date             1998-03-30
_audit_creation_method           from_xtal_archive_file_using_CIFIO
_audit_update_record             2012-06-04
_cell_angle_alpha                80.102(4)
_cell_angle_beta                 80.818(5)
_cell_angle_gamma                88.077(4)
_cell_formula_units_Z            2
_cell_length_a                   7.8676(8)
_cell_length_b                   9.1352(7)
_cell_length_c                   16.2751(9)
_cell_measurement_reflns_used    34
_cell_measurement_temperature    200
_cell_measurement_theta_max      30
_cell_measurement_theta_min      25
_cell_volume                     1137.53(16)
_diffrn_ambient_temperature      200
_diffrn_detector                 'scintillation counter'
_diffrn_detector_dtime           0.690(10)
_diffrn_measured_fraction_theta_full 1.0
_diffrn_measured_fraction_theta_max 1.0
_diffrn_measurement_device_type  Stoe_Stadi-4
_diffrn_measurement_method       \w-2\q_scans
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.54183
_diffrn_reflns_av_R_equivalents  .028
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            2960
_diffrn_reflns_theta_full        54.34
_diffrn_reflns_theta_max         54.34
_diffrn_standards_decay_%        0
_diffrn_standards_interval_time  60
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    4.846
_exptl_absorpt_correction_T_max  .628272
_exptl_absorpt_correction_T_min  .41966
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   'Xtal 3.2 LSABS'
_exptl_crystal_colour            Yellow
_exptl_crystal_density_diffrn    1.271
_exptl_crystal_density_meas      ?
_exptl_crystal_description       prisms
_exptl_crystal_F_000             456
_exptl_crystal_size_max          .370
_exptl_crystal_size_mid          .174
_exptl_crystal_size_min          .100
_refine_diff_density_max         .31
_refine_diff_density_min         -.33
_refine_ls_extinction_coef       1857(162)
_refine_ls_extinction_method     Zachariasen
_refine_ls_goodness_of_fit_ref   1.137
_refine_ls_hydrogen_treatment    noref
_refine_ls_number_parameters     254
_refine_ls_number_reflns         2358
_refine_ls_R_factor_gt           .042
_refine_ls_shift/su_max          .0005
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     \w=1/[\s^2^(Fo)+0.0001(Fo^2^)]
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         .037
_reflns_number_gt                2299
_reflns_number_total             2788
_reflns_threshold_expression     'refl observed if Fo > 3.99 \s(Fo)'
_cod_data_source_file            om300427j_si_002.cif
_cod_data_source_block           LICA
_cod_depositor_comments
;
The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'not_measured' was changed to '?'
- the value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 
;
_cod_original_cell_volume        1137.53(14)
_cod_original_sg_symbol_H-M      P-1
_cod_database_code               4078797