Delicate heterocyclic π-extension in MR-TADF emitters: balancing <i>k</i><sub>RISC</sub> enhancement and emission narrowing.
Li, Jie; Cheng, Zhang-Li; Zhang, Shu-Qi; Wang, Yue; Wang, Hui; Zhou, Jie-Yu; Gao, Wen; Qu, Ling-Wei; Zhu, Zhe-Yu; Yu, Jia; Ye, Jun; Wang, Kai; Physical chemistry chemical physics : PCCP 28 (2026) 2049–2053; doi:10.1039/d5cp04299b

data_7251714
_publ_section_title
;
 Delicate heterocyclic &#x3c0;-extension in MR-TADF emitters: balancing
 <i>k</i><sub>RISC</sub> enhancement and emission narrowing.
;
_journal_issue                   3
_journal_name_full               'Physical chemistry chemical physics : PCCP'
_journal_page_first              2049
_journal_page_last               2053
_journal_paper_doi               10.1039/d5cp04299b
_journal_volume                  28
_journal_year                    2026
_chemical_formula_moiety         'C54 H48 B N3 O2'
_chemical_formula_sum            'C54 H48 B N3 O2'
_chemical_formula_weight         781.76
_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
_atom_sites_solution_primary     dual
_audit_creation_date             2023-11-16
_audit_creation_method
;
Olex2 1.5-alpha
(compiled 2023.08.24 svn.re1ec1418 for OlexSys, GUI svn.r6817)
;
_audit_update_record
;
2024-03-20 deposited with the CCDC.	2025-12-26 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 94.755(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   18.3152(6)
_cell_length_b                   23.5978(6)
_cell_length_c                   9.6171(3)
_cell_measurement_reflns_used    4107
_cell_measurement_temperature    100
_cell_measurement_theta_max      63.474
_cell_measurement_theta_min      3.061
_cell_volume                     4142.2(2)
_computing_cell_refinement       'SAINT V8.40A (Bruker, 2019)'
_computing_data_reduction        'SAINT V8.40A (Bruker, 2019)'
_computing_molecular_graphics    'Olex2 1.5-alpha (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5-alpha (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2019/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT  (Sheldrick, 2015)'
_diffrn_ambient_temperature      100
_diffrn_measured_fraction_theta_full 0.971
_diffrn_measured_fraction_theta_max 0.971
_diffrn_measurement_device_type  'Bruker D8 VENTURE'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0
_diffrn_reflns_av_unetI/netI     0.1108
_diffrn_reflns_Laue_measured_fraction_full 0.971
_diffrn_reflns_Laue_measured_fraction_max 0.971
_diffrn_reflns_number            6613
_diffrn_reflns_point_group_measured_fraction_full 0.971
_diffrn_reflns_point_group_measured_fraction_max 0.971
_diffrn_reflns_theta_full        63.674
_diffrn_reflns_theta_max         63.674
_diffrn_reflns_theta_min         2.421
_diffrn_source_current           1.2
_diffrn_source_power             0.06
_diffrn_source_voltage           50.0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.585
_exptl_absorpt_correction_T_max  0.752370
_exptl_absorpt_correction_T_min  0.429733
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
 TWINABS-2012/1 (Bruker,2012) was used for absorption correction.
 
For component 1:
 wR2(int) was 0.1376 before and 0.0864 after correction.
 
For component 2:
 wR2(int) was 0.1363 before and 0.0877 after correction.
 The Ratio of minimum to maximum transmission is 0.57.

Final HKLF 4 output contains 37363 reflections, Rint = 0.1404
 (18220 with I > 3sig(I), Rint = 0.1033)
;
_exptl_crystal_colour            pink
_exptl_crystal_colour_primary    pink
_exptl_crystal_density_diffrn    1.254
_exptl_crystal_description       block
_exptl_crystal_F_000             1656
_exptl_crystal_size_max          0.15
_exptl_crystal_size_mid          0.07
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.739
_refine_diff_density_min         -0.494
_refine_diff_density_rms         0.093
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.042
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     570
_refine_ls_number_reflns         6613
_refine_ls_number_restraints     30
_refine_ls_restrained_S_all      1.048
_refine_ls_R_factor_all          0.1472
_refine_ls_R_factor_gt           0.0983
_refine_ls_shift/su_max          0.009
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0926P)^2^+20.2761P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2453
_refine_ls_wR_factor_ref         0.2767
_reflns_Friedel_coverage         0.000
_reflns_number_gt                4493
_reflns_number_total             6613
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5cp04299b2.cif
_cod_data_source_block           1
_cod_database_code               7251714
_shelx_shelxl_version_number     2019/3
_shelx_estimated_absorpt_t_max   0.977
_shelx_estimated_absorpt_t_min   0.917
_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. Restrained distances
 C55-C51 \\sim C52-C51 \\sim C56-C51 \\sim C53-C51
 with sigma of 0.02
3. Uiso/Uaniso restraints and constraints
Uanis(C52) \\sim Ueq, Uanis(C53) \\sim Ueq, Uanis(C56) \\sim Ueq, Uanis(C55)
\\sim Ueq: with sigma of 0.001 and sigma for terminal atoms of 0.002
4. Others
 Fixed Sof: C53(0.75) H53A(0.75) H53B(0.75) H53C(0.75) C52(0.75) H52A(0.75)
 H52B(0.75) H52C(0.75) C55(0.25) H55A(0.25) H55B(0.25) H55C(0.25) C56(0.25)
 H56A(0.25) H56B(0.25) H56C(0.25)
5.a Aromatic/amide H refined with riding coordinates:
 C24(H24), C28(H28), C25(H25), C41(H41), C26(H26), C7(H7), C14(H14), C16(H16),
 C36(H36), C44(H44), C46(H46), C10(H10), C38(H38), C42(H42), C50(H50), C43(H43),
  C49(H49), C6(H6), C35(H35), C47(H47), C37(H37)
5.b Idealised Me refined as rotating group:
 C19(H19A,H19B,H19C), C18(H18A,H18B,H18C), C2(H2A,H2B,H2C), C20(H20A,H20B,
 H20C), C3(H3A,H3B,H3C), C4(H4A,H4B,H4C), C54(H54A,H54B,H54C), C53(H53A,H53B,
 H53C), C52(H52A,H52B,H52C), C55(H55A,H55B,H55C), C56(H56A,H56B,H56C)
;
_olex2_submission_special_instructions 'No special instructions were received'