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_7110477
_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            'C21 H25 O Si Ta'
_chemical_formula_weight         502.45
_chemical_name_systematic
;

 ?

;
_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     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL
_cell_angle_alpha                90.00
_cell_angle_beta                 100.5390(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   8.6366(5)
_cell_length_b                   15.9753(9)
_cell_length_c                   14.8619(8)
_cell_measurement_temperature    203(2)
_cell_volume                     2015.9(2)
_computing_cell_refinement       'Siemens XSCANS'
_computing_data_collection       'Siemens XSCANS'
_computing_data_reduction        'Siemens SHELXTL'
_computing_molecular_graphics    'Siemens SHELXTL'
_computing_publication_material  'Siemens SHELXTL'
_computing_structure_refinement  'SHELXL-93 (Sheldrick, 1993)'
_computing_structure_solution    'SHELXS-86 (Sheldrick, 1990)'
_diffrn_ambient_temperature      203(2)
_diffrn_measurement_device       'Siemens P4'
_diffrn_measurement_method       '\w 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  0.0254
_diffrn_reflns_av_sigmaI/netI    0.0268
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            14647
_diffrn_reflns_theta_max         28.30
_diffrn_reflns_theta_min         1.89
_exptl_absorpt_coefficient_mu    5.516
_exptl_absorpt_correction_type   SADABS
_exptl_crystal_density_diffrn    1.655
_exptl_crystal_F_000             984
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.979
_refine_diff_density_min         -0.757
_refine_diff_density_rms         0.097
_refine_ls_extinction_coef       0.00034(7)
_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_all   1.040
_refine_ls_goodness_of_fit_obs   1.073
_refine_ls_matrix_type           full
_refine_ls_number_parameters     230
_refine_ls_number_reflns         4717
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.059
_refine_ls_restrained_S_obs      1.073
_refine_ls_R_factor_all          0.0285
_refine_ls_R_factor_obs          0.0225
_refine_ls_shift/esd_max         -0.116
_refine_ls_shift/esd_mean        0.002
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0229P)^2^+2.6578P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0563
_refine_ls_wR_factor_obs         0.0535
_reflns_number_observed          4177
_reflns_number_total             4719
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            900895ksup1.cif
_cod_data_source_block           ged10
_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 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc
w=1/[\s^2^(Fo^2^)+(0.0229P)^2^+2.6578P] where P=(Fo^2^+2Fc^2^)/3' was
changed to 'calc'. New tag '_refine_ls_weighting_details' was
created. The value of the new tag was set to
'w=1/[\s^2^(Fo^2^)+(0.0229P)^2^+2.6578P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_sg_symbol_H-M      P2(1)/n
_cod_database_code               7110477