Disentangling chemical pressure and superexchange effects in lanthanide–organic valence tautomerism
Viborg, Anton; Dunstan, Maja A.; Yutronkie, Nathan J.; Chanda, Amit; Trier, Felix; Pryds, Nini; Wilhelm, Fabrice; Rogalev, Andrei; Pinkowicz, Dawid; Pedersen, Kasper S.; Chemical Science 16 (2025) 6879–6885; doi:10.1039/D5SC01246E

data_1574086
_publ_section_title
;
 Disentangling chemical pressure and superexchange effects in
 lanthanide--organic valence tautomerism
;
_journal_issue                   16
_journal_name_full               'Chemical Science'
_journal_page_first              6879
_journal_page_last               6885
_journal_paper_doi               10.1039/D5SC01246E
_journal_volume                  16
_journal_year                    2025
_chemical_formula_moiety         'C12 H16 I2 N4 O Sr'
_chemical_formula_sum            'C12 H16 I2 N4 O Sr'
_chemical_formula_weight         573.71
_chemical_name_systematic
catena-[bis(pyrazine)-tetrahydrofuran-diiodo-samarium(ii)]
_chemical_properties_physical    Moisture-sensitive
_space_group_crystal_system      monoclinic
_space_group_IT_number           11
_space_group_name_Hall           '-P 2yb'
_space_group_name_H-M_alt        'P 1 21/m 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2024-11-13
_audit_creation_method
;
Olex2 1.5
(compiled 2024.02.16 svn.r378c4104 for OlexSys, GUI svn.r6928)
;
_audit_update_record
;
2025-01-28 deposited with the CCDC.	2025-03-07 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 94.7400(10)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   9.07390(10)
_cell_length_b                   8.20390(10)
_cell_length_c                   12.71610(10)
_cell_measurement_reflns_used    8852
_cell_measurement_temperature    294.99(10)
_cell_measurement_theta_max      76.3140
_cell_measurement_theta_min      3.4370
_cell_volume                     943.366(17)
_computing_cell_refinement       'CrysAlisPro 1.171.44.68a (Rigaku OD, 2024)'
_computing_data_collection
'CrysAlisPro system (CCD 43.136a 64-bit (release 23-08-2024))'
_computing_data_reduction        'CrysAlisPro 1.171.44.68a (Rigaku OD, 2024)'
_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_environment      air
_diffrn_ambient_temperature      294.99(10)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 10.6146
_diffrn_detector_type            Atlas
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.993
_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    -81.00  15.00   1.00    5.00    --  -41.18  99.00-134.00   96
  2  \w      6.00  81.00   1.00    5.00    --   41.18 -99.00 119.00   75
  3  \w     32.00 107.00   1.00   15.00    --  112.00 -99.00 119.00   75
  4  \w    104.00 178.00   1.00   15.00    --  112.00  99.00-134.00   74
  5  \w   -121.00   0.00   1.00    5.00    --  -41.18 -19.00  90.00  121
  6  \w   -121.00   0.00   1.00    5.00    --  -41.18 -19.00  90.00  121
  7  \w     17.00 115.00   1.00    5.00    --   41.18  38.00  60.00   98
  8  \w    104.00 178.00   1.00   15.00    --  112.00 111.00-180.00   74
  9  \w     39.00 109.00   1.00   15.00    --  112.00-111.00-150.00   70
 10  \w     39.00 109.00   1.00   15.00    --  112.00-111.00-150.00   70
 11  \w    104.00 178.00   1.00   15.00    --  112.00 111.00 120.00   74
 12  \w    103.00 178.00   1.00   15.00    --  112.00  77.00-150.00   75
 13  \w    103.00 178.00   1.00   15.00    --  112.00  77.00-150.00   75
 14  \w     39.00 138.00   1.00   15.00    --  112.00 -45.00 120.00   99
 15  \w     36.00 145.00   1.00   15.00    --  112.00 -77.00 120.00  109
 16  \w     36.00 140.00   1.00   15.00    --  112.00 -30.00 120.00  104
 17  \w     36.00 140.00   1.00   15.00    --  112.00 -30.00 120.00  104
 18  \w     39.00 109.00   1.00   15.00    --  112.00-111.00  60.00   70
 19  \w    104.00 178.00   1.00   15.00    --  112.00 111.00  90.00   74
 20  \w    -69.00  32.00   1.00    5.00    --  -41.18  57.00  30.00  101
 21  \w   -115.00 -17.00   1.00    5.00    --  -41.18 -38.00-120.00   98
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'SuperNova, Dual, Cu at home/near, Atlas'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      -0.0515093000
_diffrn_orient_matrix_UB_12      0.1773255000
_diffrn_orient_matrix_UB_13      0.0132324000
_diffrn_orient_matrix_UB_21      0.0154692000
_diffrn_orient_matrix_UB_22      -0.0206271000
_diffrn_orient_matrix_UB_23      0.1208135000
_diffrn_orient_matrix_UB_31      0.1615661000
_diffrn_orient_matrix_UB_32      0.0584613000
_diffrn_orient_matrix_UB_33      0.0032059000
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0408
_diffrn_reflns_av_unetI/netI     0.0210
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.993
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            9871
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.993
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         76.462
_diffrn_reflns_theta_min         3.488
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'SuperNova (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    29.678
_exptl_absorpt_correction_T_max  0.583
_exptl_absorpt_correction_T_min  0.031
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.44.68a (Rigaku Oxford Diffraction, 2024)
Numerical absorption correction based on gaussian integration over
a multifaceted crystal model
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            'clear light colourless'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_modifier   light
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    2.020
_exptl_crystal_description       plank
_exptl_crystal_F_000             536
_exptl_crystal_preparation
'A warm solution of strontiumdiiodide in tetrahydrofuran was added to a melt of pyrazine and left to cool'
_exptl_crystal_recrystallization_method
'Single crystals were obtained directly from the reaction mixture'
_exptl_crystal_size_max          0.473
_exptl_crystal_size_mid          0.112
_exptl_crystal_size_min          0.09
_refine_diff_density_max         1.489
_refine_diff_density_min         -1.351
_refine_diff_density_rms         0.180
_refine_ls_extinction_coef       0.0022(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2019/2 (Sheldrick 2019)'
_refine_ls_goodness_of_fit_ref   1.087
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     116
_refine_ls_number_reflns         2106
_refine_ls_number_restraints     30
_refine_ls_restrained_S_all      1.097
_refine_ls_R_factor_all          0.0365
_refine_ls_R_factor_gt           0.0364
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0716P)^2^+0.9240P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1039
_refine_ls_wR_factor_ref         0.1042
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2082
_reflns_number_total             2106
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc01246e2.cif
_cod_data_source_block           SrI2pyz2thf_295K
_cod_depositor_comments
'Adding full bibliography for 1574084--1574088.cif.'
_cod_database_code               1574086
_shelx_shelxl_version_number     2019/3
_chemical_oxdiff_formula         'C12 H16 N4 O Sr I2'
_shelx_estimated_absorpt_t_max   0.175
_shelx_estimated_absorpt_t_min   0.025
_diffrn_oxdiff_digest_od_ed
;

;
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
2. Uiso/Uaniso restraints and constraints
O1 \\sim C6 \\sim C8 \\sim C7 \\sim C5: within 2A with sigma of 0.02 and sigma
for terminal atoms of 0.04 within 2A
3. Others
 Fixed Sof: C6(0.5) H6A(0.5) H6B(0.5) C8(0.5) H8A(0.5) H8B(0.5) C7(0.5)
 H7A(0.5) H7B(0.5) C5(0.5) H5A(0.5) H5B(0.5)
4.a Secondary CH2 refined with riding coordinates:
 C6(H6A,H6B), C8(H8A,H8B), C7(H7A,H7B), C5(H5A,H5B)
4.b Aromatic/amide H refined with riding coordinates:
 C4(H4), C3(H3), C2(H2), C1(H1)
;
_shelx_res_checksum              61382
_olex2_exptl_crystal_mounting_method
'Crystals were covered in polybutene oil under an inert atmosphere and transferred to a nylon loop placed under a stream of nitrogen gas'
_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 3.113
_oxdiff_exptl_absorpt_empirical_full_min 0.491