Characterization of two conformers in the co-ordination chemistry of 3,4-bis(cyanamido)cyclobutane-1,2-dione dianion: syntheses, crystal structures, and electrochemical study of nickel(ii) complexes
Galibert, Anne Marie; Cortadellas, Olivier; Soula, Brigitte; Donnadieu, Bruno; Fabre, Paul-Louis; Journal of the Chemical Society, Dalton Transactions  (2002) 3743–; doi:10.1039/b202085h

data_7011597
_publ_section_title
;
 Characterization of two conformers in the co-ordination chemistry of
 3,4-bis(cyanamido)cyclobutane-1,2-dione dianion: syntheses, crystal
 structures, and electrochemical study of nickel(ii) complexes
;
_journal_issue                   19
_journal_name_full
'Journal of the Chemical Society, Dalton Transactions'
_journal_page_first              3743
_journal_paper_doi               10.1039/b202085h
_journal_year                    2002
_chemical_formula_sum            'C12 H12 N8 Ni O2'
_chemical_formula_weight         359.01
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 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            4
_cell_length_a                   9.6957(7)
_cell_length_b                   11.3628(8)
_cell_length_c                   13.8338(14)
_cell_measurement_reflns_used    5000
_cell_measurement_temperature    160(2)
_cell_measurement_theta_max      26.05
_cell_measurement_theta_min      2.3
_cell_volume                     1524.1(2)
_computing_cell_refinement       'Stoe IPDS software (Stoe, 1996)'
_computing_data_collection       'Stoe IPDS software (Stoe, 1996)'
_computing_data_reduction        'XRED (Stoe, 1.08, 1996)'
_computing_molecular_graphics    'ORTEP3 for Windows (Farrugia, 1997)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SIR92 (Giacovazzo et al, 1992)'
_diffrn_ambient_temperature      160(2)
_diffrn_measured_fraction_theta_full 0.986
_diffrn_measured_fraction_theta_max 0.986
_diffrn_measurement_device       'Stoe IPDS'
_diffrn_measurement_method       \f
_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  0.0260
_diffrn_reflns_av_sigmaI/netI    0.0199
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            9782
_diffrn_reflns_theta_full        26.09
_diffrn_reflns_theta_max         26.09
_diffrn_reflns_theta_min         2.94
_diffrn_standards_decay_%        <0.1
_diffrn_standards_interval_time  'every frame'
_diffrn_standards_number         200
_exptl_absorpt_coefficient_mu    1.296
_exptl_absorpt_correction_T_max  0.851
_exptl_absorpt_correction_T_min  0.252
_exptl_absorpt_correction_type   semi-empirical
_exptl_crystal_colour            purple
_exptl_crystal_density_diffrn    1.565
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       rod
_exptl_crystal_F_000             736
_exptl_crystal_size_max          0.75
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.25
_refine_diff_density_max         0.437
_refine_diff_density_min         -0.263
_refine_diff_density_rms         0.060
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.023(13)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.039
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     208
_refine_ls_number_reflns         2972
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.039
_refine_ls_R_factor_all          0.0269
_refine_ls_R_factor_gt           0.0252
_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^)+(0.0479P)^2^+0.4904P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0676
_refine_ls_wR_factor_ref         0.0688
_reflns_number_gt                2850
_reflns_number_total             2972
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b202085h.txt
_cod_data_source_block           3
_cod_database_code               7011597
_computing_corr_abs              DIFABS
_computing_absolute_conf         'Flack H D (1983), Acta Cryst. A39, 876-881'