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_7251715
_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         'C57 H54 B2 N2 O2'
_chemical_formula_sum            'C57 H54 B2 N2 O2'
_chemical_formula_weight         820.64
_space_group_crystal_system      orthorhombic
_space_group_IT_number           61
_space_group_name_Hall           '-P 2ac 2ab'
_space_group_name_H-M_alt        'P b c a'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2024-10-16
_audit_creation_method
;
Olex2 1.5
(compiled 2024.02.16 svn.r378c4104 for OlexSys, GUI svn.r6928)
;
_audit_update_record
;
2024-10-28 deposited with the CCDC.	2025-12-26 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   26.5336(7)
_cell_length_b                   11.2734(3)
_cell_length_c                   29.7794(8)
_cell_measurement_reflns_used    5890
_cell_measurement_temperature    170
_cell_measurement_theta_max      62.644
_cell_measurement_theta_min      2.968
_cell_volume                     8907.7(4)
_computing_cell_refinement       'SAINT V8.40A (Bruker, 2019)'
_computing_data_reduction        'SAINT V8.40A (Bruker, 2019)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2019/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT  (Sheldrick, 2015)'
_diffrn_ambient_temperature      170
_diffrn_measured_fraction_theta_full 0.981
_diffrn_measured_fraction_theta_max 0.981
_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  0.1224
_diffrn_reflns_av_unetI/netI     0.0901
_diffrn_reflns_Laue_measured_fraction_full 0.981
_diffrn_reflns_Laue_measured_fraction_max 0.981
_diffrn_reflns_limit_h_max       29
_diffrn_reflns_limit_h_min       -30
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       34
_diffrn_reflns_limit_l_min       -30
_diffrn_reflns_number            40752
_diffrn_reflns_point_group_measured_fraction_full 0.981
_diffrn_reflns_point_group_measured_fraction_max 0.981
_diffrn_reflns_theta_full        63.689
_diffrn_reflns_theta_max         63.689
_diffrn_reflns_theta_min         2.968
_diffrn_source_current           1.2
_diffrn_source_power             0.06
_diffrn_source_voltage           50.0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.557
_exptl_absorpt_correction_T_max  0.7524
_exptl_absorpt_correction_T_min  0.5074
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1331 before and 0.0923 after correction.
The Ratio of minimum to maximum transmission is 0.6744.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            yellow
_exptl_crystal_colour_primary    yellow
_exptl_crystal_density_diffrn    1.224
_exptl_crystal_description       needle
_exptl_crystal_F_000             3488
_exptl_crystal_size_max          0.11
_exptl_crystal_size_mid          0.04
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.321
_refine_diff_density_min         -0.312
_refine_diff_density_rms         0.062
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.033
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     580
_refine_ls_number_reflns         7191
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.033
_refine_ls_R_factor_all          0.1489
_refine_ls_R_factor_gt           0.0921
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0729P)^2^+17.6651P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1840
_refine_ls_wR_factor_ref         0.2128
_reflns_Friedel_coverage         0.000
_reflns_number_gt                4470
_reflns_number_total             7191
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5cp04299b2.cif
_cod_data_source_block           czbno
_cod_database_code               7251715
_shelx_shelxl_version_number     2019/3
_shelx_estimated_absorpt_t_max   0.989
_shelx_estimated_absorpt_t_min   0.941
_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:
 C37(H37), C17(H17), C40(H40), C50(H50), C15(H15), C41(H41), C43(H43),
 C10(H10), C4(H4), C25(H25), C27(H27), C53(H53), C5(H5), C12(H12), C11(H11),
 C52(H52), C7(H7), C6(H6)
2.b Idealised Me refined as rotating group:
 C31(H31A,H31B,H31C), C29(H29A,H29B,H29C), C30(H30A,H30B,H30C), C45(H45A,H45B,
 H45C), C20(H20A,H20B,H20C), C55(H55A,H55B,H55C), C22(H22A,H22B,H22C), C57(H57A,
 H57B,H57C), C47(H47A,H47B,H47C), C56(H56A,H56B,H56C), C46(H46A,H46B,H46C),
 C21(H21A,H21B,H21C)
;
_olex2_submission_special_instructions 'No special instructions were received'