The ansa-effect in permethyltantalocene chemistry: a [Me2Si] ansa bridge promotes olefin-insertion and reductive-elimination reactions for [Me2Si(C5Me4)2]Ta(η2-C2H4)H and [Me2Si(C5Me4)2]TaH3
Shin, Jun Ho; Parkin, Gerard; Chemical Communications  (1999) 887–; doi:10.1039/a900895k

data_7110478
_publ_section_title
;
 The ansa-effect in permethyltantalocene chemistry: a [Me2Si] ansa bridge
 promotes olefin-insertion and reductive-elimination reactions for
 [Me2Si(C5Me4)2]Ta(\h2-C2H4)H and [Me2Si(C5Me4)2]TaH3
;
_journal_issue                   10
_journal_name_full               'Chemical Communications'
_journal_page_first              887
_journal_paper_doi               10.1039/a900895k
_journal_year                    1999
_chemical_formula_sum            'C22 H35 Si Ta'
_chemical_formula_weight         508.54
_chemical_name_systematic
;

 ?

;
_space_group_IT_number           62
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2n'
_symmetry_space_group_name_H-M   'P n m a'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   10.1777(6)
_cell_length_b                   14.7904(8)
_cell_length_c                   13.6189(8)
_cell_measurement_temperature    223(2)
_cell_volume                     2050.1(2)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      223(2)
_diffrn_measured_fraction_theta_full 0.962
_diffrn_measured_fraction_theta_max 0.962
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0306
_diffrn_reflns_av_sigmaI/netI    0.0181
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       19
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            14561
_diffrn_reflns_theta_full        28.24
_diffrn_reflns_theta_max         28.24
_diffrn_reflns_theta_min         2.03
_exptl_absorpt_coefficient_mu    5.421
_exptl_absorpt_correction_T_max  0.6132
_exptl_absorpt_correction_T_min  0.4102
_exptl_absorpt_correction_type   none
_exptl_crystal_density_diffrn    1.648
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             1016
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.10
_refine_diff_density_max         1.297
_refine_diff_density_min         -1.328
_refine_diff_density_rms         0.099
_refine_ls_extinction_coef       0.00037(10)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.193
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     128
_refine_ls_number_reflns         2535
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.193
_refine_ls_R_factor_all          0.0334
_refine_ls_R_factor_gt           0.0285
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0142P)^2^+6.6290P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0634
_refine_ls_wR_factor_ref         0.0650
_reflns_number_gt                2249
_reflns_number_total             2535
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            900895ksup1.cif
_cod_data_source_block           tas10
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' 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      Pnma
_cod_database_code               7110478