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_7042158
_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         'C51 H58 B2 N2 O4'
_chemical_formula_sum            'C51 H58 B2 N2 O4'
_chemical_formula_weight         784.61
_space_group_crystal_system      orthorhombic
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_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_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                 90
_cell_angle_gamma                90
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_cell_length_c                   18.9462(13)
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_cell_measurement_temperature    100(2)
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_cell_measurement_theta_min      2.178
_cell_volume                     4429.4(5)
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_diffrn_ambient_temperature      100(2)
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_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker X8-APEX II'
_diffrn_radiation_monochromator  helios
_diffrn_radiation_source         'rotating anode'
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_diffrn_reflns_Laue_measured_fraction_full 1.000
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_diffrn_reflns_limit_h_min       -17
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_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -23
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_diffrn_reflns_point_group_measured_fraction_full 1.000
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_diffrn_reflns_theta_full        26.000
_diffrn_reflns_theta_max         26.066
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_exptl_crystal_colour            orange
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_exptl_crystal_description       needle
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_exptl_crystal_size_min          0.03
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_refine_ls_abs_structure_details
;
 Refined as an inversion twin.
;
_refine_ls_abs_structure_Flack   0.2(8)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.028
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_refine_ls_matrix_type           full
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_refine_ls_R_factor_all          0.0330
_refine_ls_R_factor_gt           0.0288
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_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0303P)^2^+0.9293P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
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_refine_ls_wR_factor_ref         0.0690
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_reflns_Friedel_fraction_max     0.999
_reflns_number_gt                8153
_reflns_number_total             8756
_reflns_threshold_expression     'I > 2\s(I)'
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_cod_data_source_block           HS117
_cod_depositor_comments
'Adding full bibliography for 7042146--7042160.cif.'
_cod_database_code               7042158
_shelxl_version_number           2014/6
_shelx_res_checksum              92504