Reactivity of niobium(v) and tantalum(v) halides with carbonyl compounds: synthesis of simple coordination adducts, C-H bond activation, C=O protonation, and halide transfer.
Marchetti, Fabio; Pampaloni, Guido; Zacchini, Stefano; Dalton transactions (Cambridge, England : 2003)  (2007) 4343–4351; doi:10.1039/b708531a

data_7006053
_publ_section_title
;
 Reactivity of niobium(v) and tantalum(v) halides with carbonyl
 compounds: synthesis of simple coordination adducts, C-H bond
 activation, C=O protonation, and halide transfer.
;
_journal_issue                   38
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              4343
_journal_page_last               4351
_journal_paper_doi               10.1039/b708531a
_journal_year                    2007
_chemical_formula_sum            'C18 H27 F7 O6 Ta2'
_chemical_formula_weight         834.30
_chemical_name_systematic
;
?
;
_space_group_IT_number           148
_symmetry_cell_setting           rhombohedral
_symmetry_space_group_name_Hall  '-R 3'
_symmetry_space_group_name_H-M   'R -3 :H'
_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                120.00
_cell_formula_units_Z            6
_cell_length_a                   11.3387(15)
_cell_length_b                   11.3387(15)
_cell_length_c                   32.002(8)
_cell_measurement_reflns_used    5290
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      28.2445
_cell_measurement_theta_min      2.4335
_cell_volume                     3563.2(11)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.985
_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  0.0718
_diffrn_reflns_av_sigmaI/netI    0.0424
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       41
_diffrn_reflns_limit_l_min       -41
_diffrn_reflns_number            12926
_diffrn_reflns_theta_full        27.99
_diffrn_reflns_theta_max         27.99
_diffrn_reflns_theta_min         1.91
_exptl_absorpt_coefficient_mu    9.292
_exptl_absorpt_correction_T_max  0.4018
_exptl_absorpt_correction_T_min  0.2856
_exptl_absorpt_correction_type   empirical
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    2.333
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             2352
_exptl_crystal_size_max          0.18
_exptl_crystal_size_mid          0.14
_exptl_crystal_size_min          0.12
_refine_diff_density_max         1.907
_refine_diff_density_min         -2.345
_refine_diff_density_rms         0.234
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.030
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     103
_refine_ls_number_reflns         1887
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.030
_refine_ls_R_factor_all          0.0455
_refine_ls_R_factor_gt           0.0343
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0533P)^2^+13.5225P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0855
_refine_ls_wR_factor_ref         0.0931
_reflns_number_gt                1535
_reflns_number_total             1887
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b708531a.txt
_cod_data_source_block           r-3
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Rhombohedral' changed to 'rhombohedral'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 
;
_cod_original_sg_symbol_H-M      R-3
_cod_database_code               7006053