Olefin Substitution in (silox)3M(olefin) (silox =tBu3SiO; M = Nb, Ta): The Role of Density of States in Second vs Third Row Transition Metal Reactivity
Kurt F. Hirsekorn; Elliott B. Hulley; Peter T. Wolczanski; Thomas R. Cundari; Journal of the American Chemical Society 130 (2008) 1183–1196; doi:10.1021/ja074972j

data_4107344
_publ_section_title
;
 Olefin Substitution in (silox)3M(olefin) (silox =tBu3SiO; M = Nb, Ta):
 The Role of Density of States in Second vs Third Row Transition Metal
 Reactivity
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              1183
_journal_page_last               1196
_journal_paper_doi               10.1021/ja074972j
_journal_volume                  130
_journal_year                    2008
_chemical_formula_moiety         'C42 H91 Nb O3 Si3'
_chemical_formula_sum            'C45 H91 Nb O3 Si3'
_chemical_formula_weight         857.36
_chemical_name_systematic
; 
 ? 
;
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_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
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_cell_angle_beta                 90.974(1)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   12.6914(5)
_cell_length_b                   17.3097(7)
_cell_length_c                   22.8051(8)
_cell_measurement_reflns_used    4854
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      22.17
_cell_measurement_theta_min      2.17
_cell_volume                     5009.2(3)
_computing_cell_refinement       'Bruker SAINT+'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT+'
_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      173(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker X8 APEX II diffractometer'
_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  0.0641
_diffrn_reflns_av_sigmaI/netI    0.0592
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       19
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            34386
_diffrn_reflns_theta_full        23.26
_diffrn_reflns_theta_max         23.26
_diffrn_reflns_theta_min         1.48
_exptl_absorpt_coefficient_mu    0.346
_exptl_absorpt_correction_T_max  0.9931
_exptl_absorpt_correction_T_min  0.9340
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            green
_exptl_crystal_density_diffrn    1.137
_exptl_crystal_density_meas      0
_exptl_crystal_description       plate
_exptl_crystal_F_000             1872
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.436
_refine_diff_density_min         -0.364
_refine_diff_density_rms         0.062
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.026
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     526
_refine_ls_number_reflns         7167
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.026
_refine_ls_R_factor_all          0.0668
_refine_ls_R_factor_gt           0.0396
_refine_ls_shift/su_max          0.519
_refine_ls_shift/su_mean         0.038
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0341P)^2^+4.8423P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0858
_refine_ls_wR_factor_ref         0.0958
_reflns_number_gt                5227
_reflns_number_total             7167
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja074972j-file005.cif
_cod_data_source_block           kh4
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