Pyridine-boryl radicals-mediated reductive homocoupling of para-quinone methides
Wang, Yan-Bo; Cui, Yan-Zhao; Li, He; Liu, Huiyi; Yuan, Hao-Qi; Zhou, Hao-Tian; Wang, Xiao-Sai; Organic & Biomolecular Chemistry  (2025) –; doi:10.1039/D6OB00078A

data_7161086
_publ_section_title
;
 Pyridine-boryl radical-mediated reductive homocoupling of
 <i>para</i>-quinone methides.
;
_journal_issue                   15
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              3295
_journal_page_last               3300
_journal_paper_doi               10.1039/d6ob00078a
_journal_volume                  24
_journal_year                    2026
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C42 H52 O2'
_chemical_formula_sum            'C42 H52 O2'
_chemical_formula_weight         588.83
_chemical_name_systematic
(E)-4,4'-(1,2-diphenylethene-1,2-diyl)bis(2,6-di-tert-butylphenol)
_space_group_crystal_system      orthorhombic
_space_group_IT_number           33
_space_group_name_Hall           'P 2c -2n'
_space_group_name_H-M_alt        'P n a 21'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     dual
_atom_sites_solution_secondary   difmap
_audit_creation_date             2026-01-13
_audit_creation_method
;
Olex2 1.5
(compiled 2022.04.07 svn.rca3783a0 for OlexSys, GUI svn.r6498)
;
_audit_update_record
;
2026-01-13 deposited with the CCDC.	2026-03-20 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   29.342(2)
_cell_length_b                   10.2930(8)
_cell_length_c                   11.6592(10)
_cell_measurement_reflns_used    3651
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      23.026
_cell_measurement_theta_min      2.639
_cell_volume                     3521.3(5)
_computing_cell_refinement       'SAINT V8.40B (Bruker, 2016)'
_computing_data_collection       'Bruker D8 Venture diffractometer'
_computing_data_reduction        'SAINT V8.40B (Bruker, 2016)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2025/1 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT 2014/5 (Sheldrick, 2014)'
_diffrn_ambient_temperature      173(2)
_diffrn_detector                 'Bruker PHOTON-II area detector'
_diffrn_detector_area_resol_mean 7.4
_diffrn_detector_type            'CMOS-PHOTONII area detector'
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device       'three-circle diffractometer'
_diffrn_measurement_device_type  'Bruker D8 Venture_Air'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0891
_diffrn_reflns_av_unetI/netI     0.1100
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       39
_diffrn_reflns_limit_h_min       -38
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            22529
_diffrn_reflns_point_group_measured_fraction_full 0.953
_diffrn_reflns_point_group_measured_fraction_max 0.930
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.296
_diffrn_reflns_theta_min         2.097
_diffrn_source                   'sealed X-ray tube'
_diffrn_source_current           1.4
_diffrn_source_power             0.07
_diffrn_source_target            Mo
_diffrn_source_voltage           50.0
_exptl_absorpt_coefficient_mu    0.066
_exptl_absorpt_correction_T_max  0.0962
_exptl_absorpt_correction_T_min  0.0599
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1293 before and 0.0740 after correction.
The Ratio of minimum to maximum transmission is 0.6227.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            'clear reddish red'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_modifier   reddish
_exptl_crystal_colour_primary    red
_exptl_crystal_density_diffrn    1.111
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1280
_exptl_crystal_recrystallization_method
'The crystals were growth by means of evaporation of a mixture of n-hexane and toluene at RT.'
_exptl_crystal_size_max          0.16
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.331
_refine_diff_density_min         -0.334
_refine_diff_density_rms         0.050
_refine_ls_abs_structure_details
;
 Flack x determined using 1438 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.4(10)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.012
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     431
_refine_ls_number_reflns         8133
_refine_ls_number_restraints     6
_refine_ls_restrained_S_all      1.028
_refine_ls_R_factor_all          0.1311
_refine_ls_R_factor_gt           0.0686
_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^)+(0.0586P)^2^+1.0161P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1395
_refine_ls_wR_factor_ref         0.1728
_reflns_Friedel_coverage         0.777
_reflns_Friedel_fraction_full    0.901
_reflns_Friedel_fraction_max     0.854
_reflns_number_gt                4910
_reflns_number_total             8133
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d6ob00078a2.cif
_cod_data_source_block           M16651_0m
_cod_depositor_comments
;
The following automatic conversions were performed:

data item '_diffrn_radiation_probe' value 'X-ray' was changed to
'x-ray' in accordance with the
/home/data/users/saulius/crontab/automatic-downloads/rss-feeds/RSC/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 last updated on
2011-04-26.

Automatic conversion script
Id: cif_fix_values 8170 2020-07-09 18:12:32Z antanas 

 Adding full bibliography for 7161083--7161088.cif.
;
_cod_database_code               7161086
_shelx_shelxl_version_number     2025/1
_shelx_estimated_absorpt_t_max   0.990
_shelx_estimated_absorpt_t_min   0.990
_exptl_crystal_mounting_method
;
 Crystals were removed from the crystallisation vial and immediately coated
 with PDMS (polydimethylsiloxane/Dimethicone, CAS: 9006-65-9 on a glass slide.
 A suitable single crystal was selected and mounted on a glass fiber using
 vacuum silicone grease as adhesive. The glass fiber with single crystal was
 mounted on copper pin with solid paraffin. Operator: DJ_Tokyo.
;
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups
 At 1.5 times of:
  All C(H,H) groups, All C(H,H,H) groups, All O(H) groups
2. Restrained distances
 H1-H18A
 1.98 with sigma of 0.01
 H1-H17B
 2.2 with sigma of 0.01
 H18A-H1
 2.2 with sigma of 0.01
 H2-H38A
 2.2 with sigma of 0.01
 H37B-H2
 2.2 with sigma of 0.01
3.a Aromatic/amide H refined with riding coordinates:
 C4(H4), C5(H5), C6(H6), C7(H7), C8(H8), C10(H10), C14(H14), C24(H24),
 C25(H25), C26(H26), C27(H27), C28(H28), C30(H30), C34(H34)
3.b Idealised Me refined as rotating group:
 C16(H16A,H16B,H16C), C17(H17A,H17B,H17C), C18(H18A,H18B,H18C), C21(H21A,H21B,
 H21C), C22(H22A,H22B,H22C), C36(H36A,H36B,H36C), C37(H37A,H37B,H37C), C38(H38A,
 H38B,H38C), C41(H41A,H41B,H41C), C42(H42A,H42B,H42C)
3.c Idealised tetrahedral OH refined as rotating group:
 O1(H1), O2(H2)
;
_shelx_res_checksum              98986
_olex2_submission_special_instructions 'No special instructions were received'