B-B bond activation and NHC ring-expansion reactions of diboron(4) compounds, and accurate molecular structures of B2(NMe2)4, B2eg2, B2neop2 and B2pin2.
Eck, Martin; Würtemberger-Pietsch, Sabrina; Eichhorn, Antonius; Berthel, Johannes H. J.; Bertermann, Rüdiger; Paul, Ursula S. D.; Schneider, Heidi; Friedrich, Alexandra; Kleeberg, Christian; Radius, Udo; Marder, Todd B.; Dalton transactions (Cambridge, England : 2003) 46 (2017) 3661–3680; doi:10.1039/c7dt00334j

data_7042153
_publ_section_title
;
 B-B bond activation and NHC ring-expansion reactions of diboron(4)
 compounds, and accurate molecular structures of B2(NMe2)4, B2eg2, B2neop2
 and B2pin2.
;
_journal_issue                   11
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              3661
_journal_page_last               3680
_journal_paper_doi               10.1039/c7dt00334j
_journal_volume                  46
_journal_year                    2017
_chemical_formula_moiety         'C25 H32 B2 N2 O4 '
_chemical_formula_sum            'C25 H32 B2 N2 O4'
_chemical_formula_weight         446.14
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/6
_audit_update_record
;
2017-01-25 deposited with the CCDC.
2017-02-21 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 99.245(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   8.3809(3)
_cell_length_b                   18.6842(6)
_cell_length_c                   15.0663(5)
_cell_measurement_reflns_used    6658
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      26.047
_cell_measurement_theta_min      2.462
_cell_volume                     2328.59(14)
_computing_cell_refinement       'Saint-NT v. 7.23'
_computing_data_collection       'APEX2 ver. 2014.1 (Bruker AXS)'
_computing_data_reduction        'Saint-NT v. 7.23'
_computing_molecular_graphics    'XP ver. 5.1 (Bruker AXS, 1998)'
_computing_publication_material  'SHELXL-2014 (Sheldrick, 2014)'
_computing_structure_refinement  'SHELXL-2014/6 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXL-2014/6 (Sheldrick, 2014)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker X8-APEX II'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_monochromator  helios
_diffrn_radiation_source         'rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0367
_diffrn_reflns_av_unetI/netI     0.0309
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       23
_diffrn_reflns_limit_k_min       -23
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            22541
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        26.000
_diffrn_reflns_theta_max         26.051
_diffrn_reflns_theta_min         1.750
_exptl_absorpt_coefficient_mu    0.084
_exptl_absorpt_correction_T_max  0.7453
_exptl_absorpt_correction_T_min  0.6094
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Sadabs 2014/3 (Bruker 2014)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.273
_exptl_crystal_description       block
_exptl_crystal_F_000             952
_exptl_crystal_size_max          0.740
_exptl_crystal_size_mid          0.440
_exptl_crystal_size_min          0.110
_refine_diff_density_max         0.386
_refine_diff_density_min         -0.251
_refine_diff_density_rms         0.052
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.022
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     304
_refine_ls_number_reflns         4597
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.022
_refine_ls_R_factor_all          0.0574
_refine_ls_R_factor_gt           0.0422
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0504P)^2^+1.1973P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1017
_refine_ls_wR_factor_ref         0.1103
_reflns_Friedel_coverage         0.000
_reflns_number_gt                3677
_reflns_number_total             4597
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c7dt00334j2.cif
_cod_data_source_block           ae147_a
_cod_depositor_comments
'Adding full bibliography for 7042146--7042160.cif.'
_cod_database_code               7042153
_shelx_estimated_absorpt_t_min   0.940
_shelx_estimated_absorpt_t_max   0.991
_shelxl_version_number           2014/6
_shelx_res_checksum              93630