6,6′-Biazulenic core as a platform for unlocking Hammett constants via electrochemical free-energy relationships
Mandigo, Joseph A.; Kelsey, Shaun R.; Applegate, Jason C.; Sabala, Rene C.; Dairo, Monisola K.; Weghorn, Carben R.; Fair, Raina; Berrie, Cindy L.; Thompson, Ward H.; Janzen, Daron E.; Barybin, Mikhail V.; RSC Advances 16 (2026) 8371–8379; doi:10.1039/D6RA00120C

data_7251590
_publ_section_title
;
 6,6&#x2032;-Biazulenic core as a platform for unlocking Hammett constants
 via electrochemical free-energy relationships
;
_journal_issue                   9
_journal_name_full               'RSC Advances'
_journal_page_first              8371
_journal_page_last               8379
_journal_paper_doi               10.1039/D6RA00120C
_journal_volume                  16
_journal_year                    2026
_chemical_formula_moiety         'C34 H34 O8 S2'
_chemical_formula_sum            'C34 H34 O8 S2'
_chemical_formula_weight         634.73
_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             2024-08-07
_audit_creation_method
;
Olex2 1.5
(compiled 2024.02.16 svn.r378c4104 for OlexSys, GUI svn.r6928)
;
_audit_update_record
;
2025-08-23 deposited with the CCDC.	2026-02-04 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 92.212(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   17.2376(8)
_cell_length_b                   11.8058(5)
_cell_length_c                   15.3135(7)
_cell_measurement_reflns_used    9993
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      29.102
_cell_measurement_theta_min      2.179
_cell_volume                     3114.0(2)
_computing_cell_refinement       'SAINT V8.40B (?, 2016)'
_computing_data_reduction        'SAINT V8.40B (?, 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 2019/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_temperature      100.15
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0521
_diffrn_reflns_av_unetI/netI     0.0186
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -20
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            96802
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.350
_diffrn_reflns_theta_min         2.091
_diffrn_source                   'fine-focus sealed-tube'
_exptl_absorpt_coefficient_mu    0.220
_exptl_absorpt_correction_T_max  0.7461
_exptl_absorpt_correction_T_min  0.6989
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1003 before and 0.0571 after correction.
The Ratio of minimum to maximum transmission is 0.9367.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            red
_exptl_crystal_density_diffrn    1.354
_exptl_crystal_description       plate
_exptl_crystal_F_000             1336
_exptl_crystal_size_max          0.4
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.1
_refine_diff_density_max         1.595
_refine_diff_density_min         -0.477
_refine_diff_density_rms         0.068
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.057
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     593
_refine_ls_number_reflns         5697
_refine_ls_number_restraints     279
_refine_ls_restrained_S_all      1.044
_refine_ls_R_factor_all          0.0693
_refine_ls_R_factor_gt           0.0592
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0772P)^2^+5.3055P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1546
_refine_ls_wR_factor_ref         0.1640
_reflns_Friedel_coverage         0.000
_reflns_number_gt                4873
_reflns_number_total             5697
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d6ra00120c2.cif
_cod_data_source_block           zzz
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               7251590
_shelx_shelxl_version_number     2019/3
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2. Restrained distances
 C1-C14 \\sim C1A-C14 \\sim C1B-C14
 with sigma of 0.02
 C10-C3 \\sim C10-C3A \\sim C10-C3B
 with sigma of 0.0025
 C14-O4 \\sim C14-O4A
 with sigma of 0.02
 O4-C15 \\sim O4A-C15A
 with sigma of 0.02
 C15-C16 \\sim C15A-C16A
 with sigma of 0.02
 C14-C15 \\sim C14-C15A
 with sigma of 0.04
 O4-C16 \\sim O4A-C16A
 with sigma of 0.04
3. Uiso/Uaniso restraints and constraints
All non-hydrogen atoms have similar U: within 1.2A with sigma of 0.01 and sigma
for terminal atoms of 0.02 within 1.2A
Uanis(C1) \\sim Ueq, Uanis(C1A) \\sim Ueq, Uanis(C1B) \\sim Ueq: with sigma of
0.005 and sigma for terminal atoms of 0.002
Uanis(C1) = Uanis(C1A) = Uanis(C1B)
Uanis(C3) = Uanis(C3A) = Uanis(C3B)
4. Same fragment restrains
{C17A, S1A, C1A, C2A, C3A, C11A, O1A, O2A, C12A, C13A} sigma for 1-2: 0.02,
1-3: 0.04
{C17B, S1B, C1B, C2B, C3B, C11B, O1B, O2B, C12B, C13B} sigma for 1-2: 0.02,
1-3: 0.04
as in
{C17, S1, C1, C2, C3, C11, O1, O2, C12, C13}
5. Others
 1*[Sof(C17A)+Sof(H17G)+Sof(H17H)+Sof(H17I)+Sof(S1A)+Sof(C1A)+Sof(C2A)+
 Sof(C3A)+Sof(C11A)+Sof(O1A)+Sof(O2A)+Sof(C12A)+Sof(H12E)+Sof(H12F)+Sof(C13A)+
 Sof(H13G)+Sof(H13H)+Sof(H13I)]+1*[Sof(C17B)+Sof(H17J)+Sof(H17K)+Sof(H17L)+
 Sof(S1B)+Sof(C1B)+Sof(C2B)+Sof(C3B)+Sof(C11B)+Sof(O1B)+Sof(O2B)+Sof(C12B)+
 Sof(H12G)+Sof(H12H)+Sof(C13B)+Sof(H13J)+Sof(H13K)+Sof(H13L)]=0.5 with esd of
 0.0001
 Sof(C17A)=Sof(H17G)=Sof(H17H)=Sof(H17I)=Sof(S1A)=Sof(C1A)=Sof(C2A)=Sof(C3A)=
 Sof(C11A)=Sof(O1A)=Sof(O2A)=Sof(C12A)=Sof(H12E)=Sof(H12F)=Sof(C13A)=Sof(H13G)=
 Sof(H13H)=Sof(H13I)=FVAR(1)
 Sof(C17B)=Sof(H17J)=Sof(H17K)=Sof(H17L)=Sof(S1B)=Sof(C1B)=Sof(C2B)=Sof(C3B)=
 Sof(C11B)=Sof(O1B)=Sof(O2B)=Sof(C12B)=Sof(H12G)=Sof(H12H)=Sof(C13B)=Sof(H13J)=
 Sof(H13K)=Sof(H13L)=FVAR(2)
 Fixed Sof: C17(0.5) H17D(0.5) H17E(0.5) H17F(0.5) S1(0.5) C1(0.5) C2(0.5)
 C3(0.5) C11(0.5) O1(0.5) O2(0.5) C12(0.5) H12C(0.5) H12D(0.5) C13(0.5)
 H13D(0.5) H13E(0.5) H13F(0.5) O4(0.5) C15(0.5) H15C(0.5) H15D(0.5) C16(0.5)
 H16D(0.5) H16E(0.5) H16F(0.5) O4A(0.5) C15A(0.5) H15E(0.5) H15F(0.5) C16A(0.5)
 H16G(0.5) H16H(0.5) H16I(0.5)
6.a Secondary CH2 refined with riding coordinates:
 C12'(H12A,H12B), C15'(H15A,H15B), C12(H12C,H12D), C12A(H12E,H12F), C12B(H12G,
 H12H), C15(H15C,H15D), C15A(H15E,H15F)
6.b Aromatic/amide H refined with riding coordinates:
 C4(H4), C4'(H4'), C5(H5), C5'(H5'), C7(H7), C7'(H7'), C8(H8), C8'(H8')
6.c Idealised Me refined as rotating group:
 C13'(H13A,H13B,H13C), C16'(H16A,H16B,H16C), C17'(H17A,H17B,H17C), C17(H17D,
 H17E,H17F), C13(H13D,H13E,H13F), C17A(H17G,H17H,H17I), C13A(H13G,H13H,H13I),
 C17B(H17J,H17K,H17L), C13B(H13J,H13K,H13L), C16(H16D,H16E,H16F), C16A(H16G,
 H16H,H16I)
;
_shelx_res_checksum              46456
_olex2_submission_special_instructions 'No special instructions were received'