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_4078798
_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         'C22 H24 Cr1 O4 Si1'
_chemical_formula_sum            'C22 H24 Cr O4 Si'
_chemical_formula_weight         432.51
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_cell_angle_alpha                90
_cell_angle_beta                 94.973(6)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   10.3241(7)
_cell_length_b                   15.1982(9)
_cell_length_c                   13.3413(10)
_cell_measurement_reflns_used    8000
_cell_measurement_temperature    220
_cell_measurement_theta_max      29
_cell_measurement_theta_min      3
_cell_volume                     2085.5(2)
_computing_cell_refinement       'STOE XAREA (Stoe & Cie ,2001)'
_computing_data_collection       'STOE XAREA (Stoe & Cie ,2001)'
_computing_data_reduction        'STOE XAREA (Stoe & Cie ,2001)'
_computing_molecular_graphics    'CAMERON (Watkin et al., 1996)'
_computing_publication_material  'CRYSTALS (Betteridge et al., 2003)'
_computing_structure_refinement  'CRYSTALS (Betteridge et al., 2003)'
_computing_structure_solution    'Superflip (Palatinus L. et al. ,2007)'
_diffrn_ambient_temperature      220
_diffrn_detector                 'image plate (34 cm diameter)'
_diffrn_detector_area_resol_mean 6.67
_diffrn_detector_type            STOE
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_details      ' 120 frames, detector distance = 60 mm'
_diffrn_measurement_device       '2-circle goniometer'
_diffrn_measurement_device_type  'STOE IPDS 2'
_diffrn_measurement_method       'rotation method'
_diffrn_radiation_collimation    '0.5 mm diameter, monocapillary'
_diffrn_radiation_monochromator  'plane graphite'
_diffrn_radiation_polarisn_norm  0
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0600
_diffrn_reflns_av_unetI/netI     0.0299
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            21646
_diffrn_reflns_theta_full        29.997
_diffrn_reflns_theta_max         29.997
_diffrn_reflns_theta_min         2.607
_diffrn_source
'sealed X-ray tube, 12 x 0.4 mm long-fine focus'
_diffrn_source_current           35
_diffrn_source_power             1.93
_diffrn_source_voltage           55
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.631
_exptl_absorpt_correction_T_max  0.8678
_exptl_absorpt_correction_T_min  0.7591
_exptl_absorpt_correction_type   integration
_exptl_absorpt_process_details   'Stoe XAREA'
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.377
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             904
_exptl_crystal_size_max          0.4
_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.25
_refine_diff_density_max         0.51
_refine_diff_density_min         -0.55
_refine_ls_extinction_method     None
_refine_ls_goodness_of_fit_ref   1.7554
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     253
_refine_ls_number_reflns         4375
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0473
_refine_ls_R_factor_gt           0.0392
_refine_ls_shift/su_max          0.007256
_refine_ls_structure_factor_coef Fsqd
_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: 
 8.12 4.92 0.984 
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0481
_refine_ls_wR_factor_gt          0.0474
_refine_ls_wR_factor_ref         0.0480
_reflns_limit_h_max              14
_reflns_limit_h_min              -14
_reflns_limit_k_max              21
_reflns_limit_k_min              0
_reflns_limit_l_max              18
_reflns_limit_l_min              0
_reflns_number_gt                3793
_reflns_number_total             6075
_reflns_threshold_expression     I>2.0\s(I)
_oxford_diffrn_Wilson_B_factor   2.06
_oxford_diffrn_Wilson_scale      1.54
_oxford_refine_ls_r_factor_ref   0.0469
_oxford_refine_ls_scale          0.7751(9)
_oxford_reflns_number_all        4387
_oxford_reflns_threshold_expression_ref I>-1.0\s(I)
_cod_data_source_file            om300427j_si_002.cif
_cod_data_source_block           16
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 1891 2012-01-12 08:04:46Z andrius 
;
_cod_original_sg_symbol_H-M      'P 1 21/n 1 '
_cod_original_formula_sum        'C22 H24 Cr1 O4 Si1'
_cod_database_code               4078798