Selenium makes the difference: protonation of [FeFe]-hydrogenase mimics with diselenolato ligands.
Abul-Futouh, Hassan; El-Khateeb, Mohammad; Görls, Helmar; Asali, Khalil Jamil; Weigand, Wolfgang; Dalton transactions (Cambridge, England : 2003) 46 (2017) 2937–2947; doi:10.1039/c7dt00057j

data_7041939
_publ_section_title
;
 Selenium makes the difference: protonation of [FeFe]-hydrogenase mimics
 with diselenolato ligands.
;
_journal_issue                   9
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              2937
_journal_page_last               2947
_journal_paper_doi               10.1039/c7dt00057j
_journal_volume                  46
_journal_year                    2017
_chemical_formula_moiety         'C9 H8 Fe2 O6 Se2 Sn'
_chemical_formula_sum            'C9 H8 Fe2 O6 Se2 Sn'
_chemical_formula_weight         600.46
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_audit_update_record
;
2016-11-24 deposited with the CCDC.
2017-02-06 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 100.731(1)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.5890(2)
_cell_length_b                   11.1312(2)
_cell_length_c                   19.3376(4)
_cell_measurement_reflns_used    12633
_cell_measurement_temperature    133(2)
_cell_measurement_theta_max      27.55
_cell_measurement_theta_min      2.12
_cell_volume                     1604.97(6)
_computing_cell_refinement       DENZO
_computing_data_collection       COLLECT
_computing_data_reduction        DENZO
_computing_molecular_graphics    SHELXTL/PC
_computing_publication_material  SHELXL-97
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      133(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  KappaCCD
_diffrn_measurement_method       'phi- + omega-scan'
_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  0.0363
_diffrn_reflns_av_sigmaI/netI    0.0255
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -25
_diffrn_reflns_number            12633
_diffrn_reflns_theta_full        27.55
_diffrn_reflns_theta_max         27.55
_diffrn_reflns_theta_min         2.12
_exptl_absorpt_coefficient_mu    7.879
_exptl_absorpt_correction_T_max  0.7456
_exptl_absorpt_correction_T_min  0.5246
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS, Bruker-AXS, 2002'
_exptl_crystal_colour            red-brown
_exptl_crystal_density_diffrn    2.485
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             1120
_exptl_crystal_size_max          0.042
_exptl_crystal_size_mid          0.038
_exptl_crystal_size_min          0.022
_refine_diff_density_max         0.482
_refine_diff_density_min         -0.675
_refine_diff_density_rms         0.097
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.110
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     191
_refine_ls_number_reflns         3690
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.110
_refine_ls_R_factor_all          0.0240
_refine_ls_R_factor_gt           0.0211
_refine_ls_shift/su_max          0.007
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0139P)^2^+1.9121P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0462
_refine_ls_wR_factor_ref         0.0480
_reflns_number_gt                3458
_reflns_number_total             3690
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c7dt00057j2.cif
_cod_data_source_block           FO5635
_cod_depositor_comments
'Adding full bibliography for 7041938--7041939.cif.'
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               7041939