Synthesis of α-amino acidato derivatives of niobium and tantalum pentahalides and their conversion into iminium salts.
Bortoluzzi, Marco; Hayatifar, Mohammad; Marchetti, Fabio; Pampaloni, Guido; Zacchini, Stefano; Inorganic chemistry 54 (2015) 4047–4055; doi:10.1021/acs.inorgchem.5b00286

data_4346097
_publ_section_title
;
 Synthesis of \a-amino acidato derivatives of niobium and tantalum
 pentahalides and their conversion into iminium salts.
;
_journal_issue                   8
_journal_name_full               'Inorganic chemistry'
_journal_page_first              4047
_journal_page_last               4055
_journal_paper_doi               10.1021/acs.inorgchem.5b00286
_journal_volume                  54
_journal_year                    2015
_chemical_formula_sum            'C10 H14 Br6 N Nb'
_chemical_formula_weight         720.59
_space_group_IT_number           29
_space_group_name_Hall           'P 2c -2ac'
_space_group_name_H-M_alt        'P c a 21'
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_H-M   'P c a 21'
_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            12
_cell_length_a                   42.613(14)
_cell_length_b                   7.231(2)
_cell_length_c                   16.799(5)
_cell_measurement_reflns_used    6776
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      25.6305
_cell_measurement_theta_min      2.3895
_cell_volume                     5176(3)
_computing_cell_refinement       'APEX2 (Bruker AXS, 2006)'
_computing_data_collection       'APEX2 (Bruker AXS, 2006)'
_computing_data_reduction        'SAINT (Bruker AXS, 2004)'
_computing_molecular_graphics    'ORTEPII (Johnson, 1996)'
_computing_publication_material  'XCIF (Bruker AXS, 2001)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.972
_diffrn_measured_fraction_theta_max 0.972
_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  0.0929
_diffrn_reflns_av_unetI/netI     0.0701
_diffrn_reflns_limit_h_max       50
_diffrn_reflns_limit_h_min       -50
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            44185
_diffrn_reflns_theta_full        25.03
_diffrn_reflns_theta_max         25.03
_diffrn_reflns_theta_min         1.54
_exptl_absorpt_coefficient_mu    14.576
_exptl_absorpt_correction_T_max  0.3235
_exptl_absorpt_correction_T_min  0.1789
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details
; 
 Data were corrected for Lorentz polarization and absorption
 effects (empirical absorption correction SADABS).
 R(int) =  0.1328 (selected reflections only, before parameter refinement)
 R(int) =  0.0674 (selected reflections only, after parameter refinement)
;
_exptl_crystal_colour            red
_exptl_crystal_density_diffrn    2.774
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             3984
_exptl_crystal_size_max          0.18
_exptl_crystal_size_mid          0.12
_exptl_crystal_size_min          0.10
_refine_diff_density_max         1.441
_refine_diff_density_min         -4.452
_refine_diff_density_rms         0.275
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.49(2)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.025
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     488
_refine_ls_number_reflns         8820
_refine_ls_number_restraints     397
_refine_ls_restrained_S_all      1.006
_refine_ls_R_factor_all          0.1014
_refine_ls_R_factor_gt           0.0669
_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^)+(0.0899P)^2^+25.9840P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1516
_refine_ls_wR_factor_ref         0.1672
_reflns_number_gt                6375
_reflns_number_total             8820
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ic5b00286_si_003.cif
_cod_data_source_block           3
_cod_original_sg_symbol_H-M      Pca2(1)
_cod_database_code               4346097