Vanadocene and niobocene dihalides containing electron-withdrawing substituents in the cyclopentadienyl rings: Synthesis, characterization and cytotoxicity
Iva Klepalova; Jan Honzicek; Jaromir Vinklarek; Zdenka Padelkova; Lucie Sebestova; Martina Rezacova; Inorganica Chimica Acta 402 (2013) 109–115; doi:

data_1517127
_publ_section_title
;
 Vanadocene and niobocene dihalides containing electron-withdrawing
 substituents in the cyclopentadienyl rings: Synthesis, characterization
 and cytotoxicity
;
_journal_name_full
;
Inorganica Chimica Acta
;
_journal_page_first              109
_journal_page_last               115
_journal_volume                  402
_journal_year                    2013
_chemical_formula_moiety         'C16 H18 Br2 Nb O4'
_chemical_formula_sum            'C16 H18 Br2 Nb O4'
_chemical_formula_weight         527.03
_space_group_IT_number           60
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2n 2ab'
_symmetry_space_group_name_H-M   'P b c n'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   11.8000(5)
_cell_length_b                   6.9130(7)
_cell_length_c                   20.7381(8)
_cell_measurement_reflns_used    6640
_cell_measurement_temperature    150(1)
_cell_measurement_theta_max      27.5
_cell_measurement_theta_min      1
_cell_volume                     1691.7(2)
_computing_cell_refinement       'COLLECT and DENZO'
_computing_data_collection
'COLLECT (Hooft, 1998) and DENZO (Otwinowski & Minor, 1997)'
_computing_data_reduction        'COLLECT and DENZO'
_computing_molecular_graphics    'PLATON (Spek, 2003)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SIR92 (Altomare et al., 1994)'
_diffrn_ambient_temperature      150(1)
_diffrn_detector_area_resol_mean 9.091
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_diffrn_measurement_device_type  'Bruker Nonius KappaCCD area detector'
_diffrn_measurement_method       '\f and \w scans to fill the Ewald sphere'
_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  0.0404
_diffrn_reflns_av_sigmaI/netI    0.0352
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            6583
_diffrn_reflns_theta_full        27.49
_diffrn_reflns_theta_max         27.49
_diffrn_reflns_theta_min         3.42
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    5.451
_exptl_absorpt_correction_T_max  0.784
_exptl_absorpt_correction_T_min  0.385
_exptl_absorpt_correction_type   integration
_exptl_absorpt_process_details
;
Gaussian integration (Coppens, 1970)
;
_exptl_crystal_colour            'dark violet'
_exptl_crystal_density_diffrn    2.069
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             1028
_exptl_crystal_size_max          0.35
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.500
_refine_diff_density_min         -0.811
_refine_diff_density_rms         0.126
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.116
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     105
_refine_ls_number_reflns         1926
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.116
_refine_ls_R_factor_all          0.0426
_refine_ls_R_factor_gt           0.0310
_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^)+(0.0247P)^2^+3.1166P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0635
_refine_ls_wR_factor_ref         0.0690
_reflns_number_gt                1623
_reflns_number_total             1926
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ICA-2013-402-109-115-5.cif
_cod_data_source_block           16
_cod_database_code               1517127