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_1517126
_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         'C14 H14 Br2 Nb O4'
_chemical_formula_sum            'C14 H14 Br2 Nb O4'
_chemical_formula_weight         498.98
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90
_cell_angle_beta                 133.240(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   20.0123(5)
_cell_length_b                   7.2540(3)
_cell_length_c                   14.4631(3)
_cell_measurement_reflns_used    5848
_cell_measurement_temperature    150(1)
_cell_measurement_theta_max      27.5
_cell_measurement_theta_min      1
_cell_volume                     1529.54(9)
_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 0.990
_diffrn_measured_fraction_theta_max 0.990
_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  0.0485
_diffrn_reflns_av_sigmaI/netI    0.0329
_diffrn_reflns_limit_h_max       25
_diffrn_reflns_limit_h_min       -22
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            5821
_diffrn_reflns_theta_full        27.49
_diffrn_reflns_theta_max         27.49
_diffrn_reflns_theta_min         2.79
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    6.023
_exptl_absorpt_correction_T_max  0.531
_exptl_absorpt_correction_T_min  0.333
_exptl_absorpt_correction_type   integration
_exptl_absorpt_process_details
;
Gaussian integration (Coppens, 1970)
;
_exptl_crystal_colour            'dark green'
_exptl_crystal_density_diffrn    2.167
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             964
_exptl_crystal_size_max          0.36
_exptl_crystal_size_mid          0.24
_exptl_crystal_size_min          0.19
_refine_diff_density_max         0.558
_refine_diff_density_min         -0.820
_refine_diff_density_rms         0.124
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.126
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     96
_refine_ls_number_reflns         1747
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.126
_refine_ls_R_factor_all          0.0318
_refine_ls_R_factor_gt           0.0267
_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^)+(0.0281P)^2^+3.1866P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0614
_refine_ls_wR_factor_ref         0.0650
_reflns_number_gt                1586
_reflns_number_total             1747
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ICA-2013-402-109-115-4.cif
_cod_data_source_block           15
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               1517126