[2 + 2] Photocyclization converts thermally induced spin crossover effect into “hidden hysteresis” one
Kaźmierczak, Marcin; Weselski, Marek; Siczek, Miłosz; Wolny, Juliusz A.; Schünemann, Volker; Bronisz, Robert; Chemical Science 16 (2025) 7884–7893; doi:10.1039/D4SC05587J

data_1574228
_publ_section_title
;
 [2 + 2] Photocyclization converts thermally induced spin crossover effect
 into &#x201C;hidden hysteresis&#x201D; one
;
_journal_issue                   18
_journal_name_full               'Chemical Science'
_journal_page_first              7884
_journal_page_last               7893
_journal_paper_doi               10.1039/D4SC05587J
_journal_volume                  16
_journal_year                    2025
_chemical_formula_moiety         'C11 H8 N4 O2'
_chemical_formula_sum            'C11 H8 N4 O2'
_chemical_formula_weight         228.21
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_atom_sites_solution_hydrogens   geom
_audit_creation_date             2023-12-09
_audit_creation_method
;
Olex2 1.5
(compiled 2023.08.24 svn.re1ec1418 for OlexSys, GUI svn.r6817)
;
_audit_update_record
;
2024-06-13 deposited with the CCDC.	2025-03-25 downloaded from the CCDC.
;
_cell_angle_alpha                84.15(4)
_cell_angle_beta                 81.63(4)
_cell_angle_gamma                79.92(3)
_cell_formula_units_Z            2
_cell_length_a                   4.283(4)
_cell_length_b                   9.818(8)
_cell_length_c                   12.062(9)
_cell_measurement_reflns_used    801
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      28.9730
_cell_measurement_theta_min      4.1500
_cell_volume                     492.5(7)
_computing_cell_refinement       'CrysAlisPro 1.171.42.49 (Rigaku OD, 2022)'
_computing_data_collection       'CrysAlisPro 1.171.42.49 (Rigaku OD, 2022)'
_computing_data_reduction        'CrysAlisPro 1.171.42.49 (Rigaku OD, 2022)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2018/3 (Sheldrick, 2015)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      100(2)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 10.3456
_diffrn_detector_type            Ruby
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.874
_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    -79.00 -52.00   1.00   70.00    --   15.50 178.00-150.00   27
  2  \w    -43.00  33.00   1.00   70.00    --  -16.60  57.00-180.00   76
  3  \w   -101.00  20.00   1.00   70.00    --  -16.60 -37.00   0.00  121
  4  \w    -82.00  19.00   1.00   70.00    --  -16.60 -57.00-120.00  101
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'Xcalibur, Ruby, Gemini ultra'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      -0.0347261000
_diffrn_orient_matrix_UB_12      0.0418543000
_diffrn_orient_matrix_UB_13      0.0462302000
_diffrn_orient_matrix_UB_21      -0.1639977000
_diffrn_orient_matrix_UB_22      0.0129626000
_diffrn_orient_matrix_UB_23      -0.0076250000
_diffrn_orient_matrix_UB_31      -0.0261430000
_diffrn_orient_matrix_UB_32      -0.0591461000
_diffrn_orient_matrix_UB_33      0.0368722000
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0301
_diffrn_reflns_av_unetI/netI     0.0685
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.874
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -5
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            3680
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.874
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.817
_diffrn_reflns_theta_min         3.425
_diffrn_source                   'fine-focus sealed X-ray tube'
_diffrn_source_type              'Enhance (Mo) X-ray Source'
_exptl_absorpt_coefficient_mu    0.111
_exptl_absorpt_correction_T_max  0.993
_exptl_absorpt_correction_T_min  0.974
_exptl_absorpt_correction_type   analytical
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.42.49 (Rigaku Oxford Diffraction, 2022)
Analytical numeric absorption correction using a multifaceted crystal
model based on expressions derived by R.C. Clark & J.S. Reid.
(Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.539
_exptl_crystal_description       plate
_exptl_crystal_F_000             236
_exptl_crystal_size_max          0.319
_exptl_crystal_size_mid          0.162
_exptl_crystal_size_min          0.073
_refine_diff_density_max         0.291
_refine_diff_density_min         -0.227
_refine_diff_density_rms         0.055
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.037
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     154
_refine_ls_number_reflns         2253
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.037
_refine_ls_R_factor_all          0.0930
_refine_ls_R_factor_gt           0.0514
_refine_ls_shift/su_max          0.034
_refine_ls_shift/su_mean         0.005
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0385P)^2^+0.0046P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0931
_refine_ls_wR_factor_ref         0.1083
_reflns_Friedel_coverage         0.000
_reflns_number_gt                1506
_reflns_number_total             2253
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d4sc05587j10.cif
_cod_data_source_block           206b
_cod_depositor_comments
'Adding full bibliography for 1574226--1574232.cif.'
_cod_original_cell_volume        492.5(8)
_cod_database_code               1574228
_shelx_shelxl_version_number     2018/3
_chemical_oxdiff_formula         C11H8N4O2
_shelx_estimated_absorpt_t_max   0.992
_shelx_estimated_absorpt_t_min   0.965
_reflns_odcompleteness_completeness 99.75
_reflns_odcompleteness_iscentric 1
_reflns_odcompleteness_theta     26.32
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
2.a Secondary CH2 refined with riding coordinates:
 C10(H10A,H10B)
2.b Aromatic/amide H refined with riding coordinates:
 C2(H2), C3(H3), C5(H5), C6(H6), C8(H8), C11(H11)
;
_shelx_res_checksum              77492
_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 1.056
_oxdiff_exptl_absorpt_empirical_full_min 0.966