Dimerisation of aryl-substituted bicyclobutanes (BCBs): Revealing a new mode of 1,3-dipolar background reactivity
Werz, Daniel B.; George, Malini; Knyazev, Daniil A.; Świątek, Kamil; von Köller, Heinrich; Chemical Science  (2026) –; doi:10.1039/D6SC01258B

data_1576999
_publ_section_title
;
 Dimerisation of aryl-substituted bicyclobutanes (BCBs): revealing a new
 mode of 1,3-dipolar background reactivity.
;
_journal_issue                   20
_journal_name_full               'Chemical science'
_journal_page_first              10159
_journal_page_last               10167
_journal_paper_doi               10.1039/d6sc01258b
_journal_volume                  17
_journal_year                    2026
_chemical_formula_moiety         'C23 H20 Br2 O4'
_chemical_formula_sum            'C23 H20 Br2 O4'
_chemical_formula_weight         520.21
_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     direct
_audit_creation_method
;FinalCif V143 by Daniel Kratzert, Freiburg 2025, 
https://dkratzert.de/finalcif.html
;
_audit_update_record
;
2025-07-29 deposited with the CCDC.	2026-03-31 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 106.600(14)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   20.433(5)
_cell_length_b                   9.030(2)
_cell_length_c                   11.857(3)
_cell_measurement_reflns_used    9618
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      30.5545
_cell_measurement_theta_min      2.484
_cell_volume                     2096.6(9)
_computing_cell_refinement       'SAINT V8.41'
_computing_data_collection
'Bruker BIS 8.5.5.6/2024-10-24 and APEX6 2024.9-1'
_computing_data_reduction        'SAINT V8.41'
_computing_structure_refinement  'SHELXL-2019/2 (Sheldrick, 2019)'
_computing_structure_solution    'SHELXD (G. Sheldrick)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      100(2)
_diffrn_detector                 CPAD
_diffrn_detector_area_resol_mean 7.41
_diffrn_detector_type            'Bruker PHOTON III'
_diffrn_measured_fraction_theta_full 0.996
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device       'three-circle diffractometer'
_diffrn_measurement_device_type  'Bruker D8 VENTURE dual wavelength Mo/Cu'
_diffrn_measurement_method       '\w and \f scans'
_diffrn_measurement_specimen_support 'MiTeGen micromount'
_diffrn_radiation_monochromator  'mirror optics'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0657
_diffrn_reflns_av_unetI/netI     0.0181
_diffrn_reflns_Laue_measured_fraction_full 0.996
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       27
_diffrn_reflns_limit_h_min       -27
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            258244
_diffrn_reflns_point_group_measured_fraction_full 0.996
_diffrn_reflns_point_group_measured_fraction_max 0.997
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.281
_diffrn_reflns_theta_min         1.792
_diffrn_source                   'microfocus sealed X-ray tube'
_diffrn_source_current           1.4
_diffrn_source_type              'Incoatec I\ms'
_diffrn_source_voltage           50.0
_exptl_absorpt_coefficient_mu    3.894
_exptl_absorpt_correction_T_max  0.7461
_exptl_absorpt_correction_T_min  0.577
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;SADABS-2016/2 - Bruker AXS area detector scaling and absorption correction: 
Krause, L., Herbst-Irmer, R., Sheldrick G.M. & Stalke D., J. Appl. Cryst. 48 
(2015) 3-10
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.648
_exptl_crystal_description       block
_exptl_crystal_F_000             1040
_exptl_crystal_recrystallization_method
'Crystals were obtained at room temperature by gas-phase diffusion of n-hexaneinto a solution of the compound dissolved in dichloromethane.'
_exptl_crystal_size_max          0.364
_exptl_crystal_size_mid          0.192
_exptl_crystal_size_min          0.156
_refine_diff_density_max         1.016
_refine_diff_density_min         -1.388
_refine_diff_density_rms         0.085
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.080
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     323
_refine_ls_number_reflns         5185
_refine_ls_number_restraints     315
_refine_ls_restrained_S_all      1.051
_refine_ls_R_factor_all          0.0475
_refine_ls_R_factor_gt           0.0469
_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^)+9.5843P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1030
_refine_ls_wR_factor_ref         0.1033
_reflns_Friedel_coverage         0.000
_reflns_number_gt                5117
_reflns_number_total             5185
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d6sc01258b2.cif
_cod_data_source_block           Werz_MG537
_cod_depositor_comments
'Adding full bibliography for 1576995--1576999.cif.'
_cod_original_cell_volume        2096.5(9)
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               1576999
_shelx_shelxl_version_number     2019/3
_shelx_estimated_absorpt_t_min   0.331
_shelx_estimated_absorpt_t_max   0.582
_olex2_diffrn_ambient_temperature_device 'Oxford Cryostream 800'
_shelx_res_checksum              6076