Niobium isocyanide complexes, Nb(CNAr)<sub>6</sub>, with Ar = 2,6-dimethylphenyl (Xyl), a diamagnetic dimer containing four reductively coupled isocyanides, and Ar = 2,6-diisopropylphenyl (Dipp), a paramagnetic monomer analogous to the highly unstable hexacarbonylniobium(0).
Kucera, Benjamin E.; Roberts, Christopher J.; Young, Jr, Victor G; Brennessel, William W.; Ellis, John E.; Acta crystallographica. Section C, Structural chemistry 75 (2019) 1259–1265; doi:10.1107/S205322961901101X

data_2311999
_publ_section_title
;
 Niobium isocyanide complexes, Nb(CNAr)<sub>6</sub>, with Ar&#x00A0;=
 2,6-dimethylphenyl (Xyl), a diamagnetic dimer containing four reductively
 coupled isocyanides, and Ar&#x00A0;= 2,6-diisopropylphenyl (Dipp), a
 paramagnetic monomer analogous to the highly unstable
 hexacarbonylniobium(0).
;
_journal_coeditor_code           QF3033
_journal_issue                   'Pt 9'
_journal_name_full
'Acta crystallographica. Section C, Structural chemistry'
_journal_page_first              1259
_journal_page_last               1265
_journal_paper_doi               10.1107/S205322961901101X
_journal_volume                  75
_journal_year                    2019
_chemical_formula_iupac          '[Nb2 (C9 H9 N1)10 (C36 H36 N4)]'
_chemical_formula_moiety         'C126 H126 N14 Nb2'
_chemical_formula_sum            'C126 H126 N14 Nb2'
_chemical_formula_weight         2022.22
_chemical_name_systematic
;
Bis[\m-<i>N</i>,<i>N</i>',<i>N</i>'',<i>N</i>'''-tetrakis(2,6-\
dimethylphenyl)squaramidinato(2-)]bis[pentakis(2,6-dimethylphenyl
isocyanide)niobium(I)]
;
_space_group_crystal_system      monoclinic
_space_group_IT_number           15
_space_group_name_Hall           '-C 2yc'
_space_group_name_H-M_alt        'C 1 2/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2018/3
_cell_angle_alpha                90
_cell_angle_beta                 97.655(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   32.077(5)
_cell_length_b                   15.830(2)
_cell_length_c                   24.815(4)
_cell_measurement_reflns_used    3690
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      23.52
_cell_measurement_theta_min      2.26
_cell_volume                     12488(3)
_computing_cell_refinement
;
SAINT (Bruker, 2003)
;
_computing_data_collection
;
SMART (Bruker, 2003)
;
_computing_data_reduction
;
SAINT (Bruker, 2003)
;
_computing_molecular_graphics
;
SHELXTL (Sheldrick, 2008)
;
_computing_publication_material
;
SHELXTL (Sheldrick, 2008)
;
_computing_structure_refinement
;
SHELXL2018 (Sheldrick, 2015)
;
_computing_structure_solution
;
SHELXS97 (Sheldrick, 2008)
;
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.936
_diffrn_measured_fraction_theta_max 0.936
_diffrn_measurement_device_type  'Bruker SMART CCD platform'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0511
_diffrn_reflns_av_unetI/netI     0.0830
_diffrn_reflns_limit_h_max       38
_diffrn_reflns_limit_h_min       -24
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            22038
_diffrn_reflns_theta_full        25.075
_diffrn_reflns_theta_max         25.075
_diffrn_reflns_theta_min         1.437
_diffrn_source                   'normal-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.233
_exptl_absorpt_correction_T_max  0.9550
_exptl_absorpt_correction_T_min  0.8926
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
(SADABS; Sheldrick, 1996)
;
_exptl_crystal_colour            green-black
_exptl_crystal_density_diffrn    1.076
_exptl_crystal_description       plate
_exptl_crystal_F_000             4248
_exptl_crystal_size_max          0.50
_exptl_crystal_size_mid          0.50
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.383
_refine_diff_density_min         -0.253
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.997
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     773
_refine_ls_number_reflns         10394
_refine_ls_number_restraints     462
_refine_ls_restrained_S_all      0.987
_refine_ls_R_factor_all          0.1024
_refine_ls_R_factor_gt           0.0549
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0754P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1263
_refine_ls_wR_factor_ref         0.1444
_reflns_number_gt                6478
_reflns_number_total             10394
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            qf3033sup1.cif
_cod_data_source_block           1
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               2311999
_shelx_estimated_absorpt_t_min   0.893
_shelx_estimated_absorpt_t_max   0.955
_shelx_hkl_checksum              56824
_shelx_res_checksum              48781
_shelx_fab_checksum              89519