Synthesis of symmetrical and unsymmetrical cyclic diborenes via NHC-directed C–H borylation
Mihm, Cornelius; Kar, Sourav; Sachs, Andreas; Duwe, Dario; Dewhurst, Rian D.; Braunschweig, Holger; Chemical Science 16 (2025) 11637–11643; doi:10.1039/D5SC03150H

data_1574724
_publ_section_title
;
 Synthesis of symmetrical and unsymmetrical cyclic diborenes via
 NHC-directed C--H borylation
;
_journal_issue                   25
_journal_name_full               'Chemical Science'
_journal_page_first              11637
_journal_page_last               11643
_journal_paper_doi               10.1039/D5SC03150H
_journal_volume                  16
_journal_year                    2025
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C44 H56 B2 N4'
_chemical_formula_sum            'C44 H56 B2 N4'
_chemical_formula_weight         662.54
_space_group_crystal_system      tetragonal
_space_group_IT_number           114
_space_group_name_Hall           'P -4 2n'
_space_group_name_H-M_alt        'P -4 21 c'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     dual
_atom_sites_solution_secondary   difmap
_audit_creation_date             2023-03-29
_audit_creation_method           'CIF-fill 1.3t (K.Radacki, 2005-23)'
_audit_update_record
;
2025-04-29 deposited with the CCDC.	2025-05-27 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   18.90630(10)
_cell_length_b                   18.90630(10)
_cell_length_c                   23.2427(3)
_cell_measurement_reflns_used    41353
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      73.4770
_cell_measurement_theta_min      2.9750
_cell_volume                     8308.06(12)
_computing_cell_refinement       'CrysAlisPro 1.171.42.84a (Rigaku OD, 2023)'
_computing_data_collection       'CrysAlisPro 1.171.42.84a (Rigaku OD, 2023)'
_computing_data_reduction        'CrysAlisPro 1.171.42.84a (Rigaku OD, 2023)'
_computing_molecular_graphics    'ShelXLe (Huebschle et all, 2011)'
_computing_publication_material  'SHELXL-2018/3 (Sheldrick, 2018)'
_computing_structure_refinement  'SHELXL-2018/3 (Sheldrick, 2018)'
_computing_structure_solution    'SHELXT 2014/5 (Sheldrick, 2014)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      100(2)
_diffrn_detector                 HPA
_diffrn_detector_area_resol_mean 10.0
_diffrn_detector_type            'HyPix Arc150'
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_details
;
 List of Runs (angles in degrees, time in seconds):
 --------------------------------------------------------------------------
  1  \w     62.00 126.00   0.50    0.50    --   84.69  15.00 -30.00  128
  2  \w     97.00 133.00   0.50    0.50    --   84.69  15.00   0.00   72
  3  \w     59.00 127.00   0.50    0.50    --   84.69  15.00-120.00  136
  4  \w     66.00  92.00   0.50    0.50    --   76.90-112.00-180.00   52
  5  \w     24.00  58.00   0.50    0.50    --   71.34-126.00 -90.00   68
  6  \w     39.00  64.00   0.50    0.50    --   84.69-112.00-180.00   50
  7  \w     26.00  55.00   0.50    0.50    --   71.34-126.00 -60.00   58
  8  \w     45.00  92.00   0.50    0.50    --   76.90-112.00 -30.00   94
  9  \w     36.00  64.00   0.50    0.50    --   76.90-112.00  60.00   56
 10  \w     27.00  61.00   0.50    0.50    --   58.57 -95.00  30.00   68
 11  \w     16.00  46.00   0.50    0.50    --   58.57 -95.00  60.00   60
 12  \w     23.00  55.00   0.50    0.50    --   58.57 -95.00  90.00   64
 13  \w     36.00  61.00   0.50    0.50    --   76.90 -95.00 120.00   50
 14  \w     65.00  91.00   0.50    0.50    --   84.69 -95.00 120.00   52
 15  \w     50.00  92.00   0.50    0.50    --   76.90-112.00 150.00   84
 16  \w     16.00  52.00   0.50    0.50    --   58.57 -95.00 150.00   72
 17  \w     38.00  71.00   0.50    0.50    --   76.90 -95.00  90.00   66
 18  \w     29.00  54.00   0.50    0.50    --   71.34 -95.00 -30.00   50
 19  \w     25.00  50.00   0.50    0.50    --   58.57 -95.00 -60.00   50
 20  \w     46.00  92.00   0.50    0.50    --   84.69 -95.00 -90.00   92
 21  \w     56.00  92.00   0.50    0.50    --   84.69 -95.00-150.00   72
 22  \w     43.00  92.00   0.50    0.50    --   84.69 -95.00-180.00   98
 23  \w     44.00  92.00   0.50    0.50    --   84.69 -95.00   0.00   96
 24  \w     53.00  92.00   0.50    0.50    --   84.69 -95.00 -30.00   78
 25  \w     66.00  92.00   0.50    0.50    --   84.69 -95.00  30.00   52
 26  \w     66.00  91.00   0.50    0.50    --   84.69 -95.00 -60.00   50
 27  \w     42.00  92.00   0.50    0.50    --   84.69 -95.00  60.00  100
 28  \w     67.00  92.00   0.50    0.50    --   84.69 -95.00  90.00   50
 29  \w     66.00  91.00   0.50    0.50    --   84.69 -95.00 150.00   50
 30  \w    -99.00 -31.00   0.50    0.50    --  -60.16 -15.00-150.00  136
 31  \w   -114.00 -84.00   0.50    0.50    --  -69.76 -15.00 -60.00   60
 32  \w    -72.00 -47.00   0.50    0.50    --  -69.76 -15.00 -60.00   50
 33  \w   -127.00 -43.00   0.50    0.50    --  -76.35 -15.00 -30.00  168
 34  \w   -106.00 -80.00   0.50    0.50    --  -69.76 -15.00  30.00   52
 35  \w    -66.00 -37.00   0.50    0.50    --  -69.76 -15.00  30.00   58
 36  \w   -127.00 -40.00   0.50    0.50    --  -76.35 -15.00  60.00  174
 37  \w    -99.00 -48.00   0.50    0.50    --  -69.76 -15.00 120.00  102
 38  \w    -92.00 -60.00   0.50    0.50    --  -79.50 105.00   2.88   64
 39  \w    -68.00 -33.00   0.50    0.50    --  -76.35 112.00 150.00   70
 40  \w    -57.00 -31.00   0.50    0.50    --  -76.35 112.00 -60.00   52
 41  \w    -97.00 -33.00   0.50    0.50    --  -79.50 118.00-164.77  128
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'Rigaku XtaLAB Synergy-R'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
;
 CrysAlisPro convention (1999,Acta A55,543-557)
;
_diffrn_orient_matrix_UB_11      -0.0310794000
_diffrn_orient_matrix_UB_12      0.0208491000
_diffrn_orient_matrix_UB_13      -0.0588895000
_diffrn_orient_matrix_UB_21      0.0416036000
_diffrn_orient_matrix_UB_22      0.0700181000
_diffrn_orient_matrix_UB_23      0.0019197000
_diffrn_orient_matrix_UB_31      0.0627374000
_diffrn_orient_matrix_UB_32      -0.0360909000
_diffrn_orient_matrix_UB_33      -0.0304317000
_diffrn_radiation_monochromator  'multi-layer mirror'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
_diffrn_radiation_xray_symbol    K-L~2,3~
_diffrn_reflns_av_R_equivalents  0.0623
_diffrn_reflns_av_unetI/netI     0.0235
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       23
_diffrn_reflns_limit_h_min       -20
_diffrn_reflns_limit_k_max       23
_diffrn_reflns_limit_k_min       -23
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            109071
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.991
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         74.982
_diffrn_reflns_theta_min         3.013
_diffrn_source                   'rotating-anode X-ray tube'
_diffrn_source_type              'PhotonJet-R X-ray Source'
_exptl_absorpt_coefficient_mu    0.459
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.770
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
 CrysAlisPro 1.171.42.84a (Rigaku Oxford Diffraction, 2023) Numerical 
 absorption correction based on gaussian integration over a multifaceted 
 crystal model Empirical absorption correction using spherical harmonics, 
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            purple
_exptl_crystal_density_diffrn    1.059
_exptl_crystal_description       block
_exptl_crystal_F_000             2864
_exptl_crystal_preparation
;
 Crystals were grown from saturated solution of benzene, pentane at 25 \%C. 
 For data collection the crystal was immersed in a film of perfluoropolyether 
 oil, mounted on a polyimide loop and transferred to stream of cold nitrogen 
 (Oxford Cryostream 800).
;
_exptl_crystal_size_max          0.220
_exptl_crystal_size_mid          0.170
_exptl_crystal_size_min          0.080
_refine_diff_density_max         0.200
_refine_diff_density_min         -0.203
_refine_diff_density_rms         0.039
_refine_ls_abs_structure_details
;
 Flack x determined using 3259 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons, 
 Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.06(11)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.047
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     464
_refine_ls_number_reflns         8485
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.047
_refine_ls_R_factor_all          0.0482
_refine_ls_R_factor_gt           0.0434
_refine_ls_shift/su_max          0.013
_refine_ls_shift/su_mean         0.002
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
;
 w=1/[\s^2^(Fo^2^)+(0.0757P)^2^+1.1987P] where P=(Fo^2^+2Fc^2^)/3
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1160
_refine_ls_wR_factor_ref         0.1197
_reflns_Friedel_coverage         0.826
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.984
_reflns_number_gt                7755
_reflns_number_total             8485
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc03150h2.cif
_cod_data_source_block           diborene_7
_cod_depositor_comments
'Adding full bibliography for 1574720--1574725.cif.'
_cod_original_cell_volume        8308.06(14)
_cod_database_code               1574724
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_min   0.906
_shelx_estimated_absorpt_t_max   0.964
_shelx_res_checksum              45537
_shelx_fab_checksum              54700