Experimental and spectroscopic evidence of the hidden triplet transition state of quinone methide: a new reactivity paradigm.
Tiwari, Shashikant; Sharma, Ritika; Rawat, Diwan S.; Chemical communications (Cambridge, England) 62 (2026) 2343–2347; doi:10.1039/d5cc06672g

data_7135533
_publ_section_title
;
 Experimental and spectroscopic evidence of the hidden triplet transition
 state of quinone methide: a new reactivity paradigm.
;
_journal_issue                   7
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              2343
_journal_page_last               2347
_journal_paper_doi               10.1039/d5cc06672g
_journal_volume                  62
_journal_year                    2026
_chemical_formula_moiety         'C31 H35 N O4'
_chemical_formula_sum            'C31 H35 N O4'
_chemical_formula_weight         485.60
_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'
_atom_sites_solution_hydrogens   geom
_audit_creation_date             2024-11-26
_audit_creation_method
;
Olex2 1.3
(compiled 2020.11.12 svn.r5f609507 for OlexSys, GUI svn.r6408)
;
_audit_update_record
;
2025-02-17 deposited with the CCDC.	2025-12-22 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 97.619(3)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   9.2331(3)
_cell_length_b                   14.1143(4)
_cell_length_c                   20.5532(8)
_cell_measurement_reflns_used    10310
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      30.7790
_cell_measurement_theta_min      1.8390
_cell_volume                     2654.82(16)
_computing_cell_refinement       'CrysAlisPro 1.171.43.106a (Rigaku OD, 2024)'
_computing_data_collection       'CrysAlisPro 1.171.43.106a (Rigaku OD, 2024)'
_computing_data_reduction        'CrysAlisPro 1.171.43.106a (Rigaku OD, 2024)'
_computing_molecular_graphics    'Olex2 1.3 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.3 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2016/4 (Sheldrick, 2015)'
_diffrn_ambient_temperature      293(2)
_diffrn_detector                 'Hybrid Pixel Array Detector'
_diffrn_detector_area_resol_mean 10.0000
_diffrn_detector_type            HyPix
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.781
_diffrn_measurement_details
;
List of Runs (angles in degrees, time in seconds):

  # Type    Start    End  Width  t~exp~   \w     \q     \k     \f   Frames
  1  \w    -23.00   2.00   0.50    2.00    --   -5.38 -99.00 120.00   50
  2  \w      1.00  27.00   0.50    2.00    --   -5.38 -99.00  60.00   52
  3  \w    -12.00  22.00   0.50    2.00    --   -5.38 -99.00-150.00   68
  4  \w    -63.00  21.00   0.50    2.00    --    5.54 -63.00-142.00  168
  5  \w     -1.00  77.00   0.50    2.00    --    5.54  63.00  -5.00  156
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type
'XtaLAB Synergy, Single source at home/near, HyPix'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      0.0692123000
_diffrn_orient_matrix_UB_12      0.0103398000
_diffrn_orient_matrix_UB_13      0.0179416000
_diffrn_orient_matrix_UB_21      -0.0112562000
_diffrn_orient_matrix_UB_22      -0.0356459000
_diffrn_orient_matrix_UB_23      0.0231161000
_diffrn_orient_matrix_UB_31      0.0330260000
_diffrn_orient_matrix_UB_32      -0.0338836000
_diffrn_orient_matrix_UB_33      -0.0188654000
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0440
_diffrn_reflns_av_unetI/netI     0.0483
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.781
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       19
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -25
_diffrn_reflns_number            23182
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.781
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         31.066
_diffrn_reflns_theta_min         1.755
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'PhotonJet (Mo) X-ray Source'
_exptl_absorpt_coefficient_mu    0.080
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.59275
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.43.106a (Rigaku Oxford Diffraction, 2024)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_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    1.215
_exptl_crystal_description       block
_exptl_crystal_F_000             1040
_refine_diff_density_max         0.334
_refine_diff_density_min         -0.247
_refine_diff_density_rms         0.060
_refine_ls_extinction_coef       0.0046(10)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2016/4 (Sheldrick 2016)'
_refine_ls_goodness_of_fit_ref   1.046
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     334
_refine_ls_number_reflns         6652
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.046
_refine_ls_R_factor_all          0.0657
_refine_ls_R_factor_gt           0.0477
_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^)+(0.0704P)^2^+0.5053P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1273
_refine_ls_wR_factor_ref         0.1396
_reflns_Friedel_coverage         0.000
_reflns_number_gt                5039
_reflns_number_total             6652
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5cc06672g2.cif
_cod_data_source_block           mv-15-l_auto
_cod_database_code               7135533
_shelx_shelxl_version_number     2016/4
_chemical_oxdiff_formula         'C H O N'
_chemical_oxdiff_usercomment     19-11-2024
_reflns_odcompleteness_completeness 99.96
_reflns_odcompleteness_iscentric 1
_reflns_odcompleteness_theta     26.32
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Aromatic/amide H refined with riding coordinates:
 C2(H2), C36(H36), C6(H6), C13(H13), C32(H32), C35(H35), C34(H34), C33(H33),
 C25(H25), C27(H27), C26(H26)
2.b Idealised Me refined as rotating group:
 C16(H16A,H16B,H16C), C20(H20A,H20B,H20C), C17(H17A,H17B,H17C), C21(H21A,H21B,
 H21C), C22(H22A,H22B,H22C), C18(H18A,H18B,H18C), C11(H11A,H11B,H11C), C30(H30A,
 H30B,H30C)
;
_shelx_res_checksum              3699
_olex2_submission_special_instructions 'No special instructions were received'
_oxdiff_exptl_absorpt_empirical_details
;
Empirical correction (ABSPACK) includes:
- Absorption correction using spherical harmonics
- Frame scaling
;
_oxdiff_exptl_absorpt_empirical_full_max 1.496
_oxdiff_exptl_absorpt_empirical_full_min 0.493