Fluorenyl-Tethered N-Heterocyclic Carbene Complexes of the Heavy Alkali Metals
Burnett, Stuart; Kennedy, Alan; Mansell, Stephen M.; Weetman, Catherine Ellen; Chemical Communications  (2026) –; doi:10.1039/D5CC06477E

data_7135310
_publ_section_title
;
 Fluorenyl-Tethered N-Heterocyclic Carbene Complexes of the Heavy Alkali
 Metals
;
_journal_name_full               'Chemical Communications'
_journal_paper_doi               10.1039/D5CC06477E
_journal_year                    2026
_chemical_formula_moiety         'C27 H25 Cs N2'
_chemical_formula_sum            'C27 H25 Cs N2'
_chemical_formula_weight         510.40
_chemical_properties_physical
Air-sensitive,Moisture-sensitive,Oxygen-sensitive
_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             2025-11-06
_audit_creation_method
;
Olex2 1.5
(compiled 2025.07.13 svn.rb7424aed for OlexSys, GUI svn.r7314)
;
_audit_update_record
;
2025-11-10 deposited with the CCDC.	2025-12-04 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 100.598(1)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   14.4348(1)
_cell_length_b                   12.0323(1)
_cell_length_c                   26.6844(1)
_cell_measurement_reflns_used    53412
_cell_measurement_temperature    200(2)
_cell_measurement_theta_max      71.7150
_cell_measurement_theta_min      3.0940
_cell_volume                     4555.59(5)
_computing_cell_refinement       'CrysAlisPro 1.171.41.115a (Rigaku OD, 2021)'
_computing_data_collection       'CrysAlisPro 1.171.41.115a (Rigaku OD, 2021)'
_computing_data_reduction        'CrysAlisPro 1.171.41.115a (Rigaku OD, 2021)'
_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      N~2~
_diffrn_ambient_temperature      200(2)
_diffrn_detector                 'Hybrid Pixel Array Detector'
_diffrn_detector_area_resol_mean 10.0000
_diffrn_detector_type            HyPix3000
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_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    -83.00  -8.00   0.50    5.00    --  -39.33 119.00-172.00  150
  2  \w   -110.00 -29.00   0.50    5.00    --  -39.33 158.00 -18.00  162
  3  \w   -107.00 -51.00   0.50    5.00    --  -39.33-158.00 -52.00  112
  4  \w     51.00 107.00   0.50    5.00    --   39.33 158.00 -18.00  112
  5  \w     29.00 110.00   0.50    5.00    --   39.33-158.00 -52.00  162
  6  \w     29.00 110.00   0.50    5.00    --   39.33-158.00 -52.00  162
  7  \w      8.00  83.00   0.50    5.00    --   39.33-119.00 102.00  150
  8  \w   -164.00 -76.00   0.50   11.00    -- -101.06-119.00 102.00  176
  9  \w   -135.00 -32.00   0.50   11.00    -- -101.06 158.00 -18.00  206
 10  \w   -110.00 -38.00   0.50   11.00    -- -101.06 119.00-172.00  144
 11  \w   -135.00 -32.00   0.50   11.00    -- -101.06 158.00 -18.00  206
 12  \w     38.00 110.00   0.50   11.00    --  101.06-119.00 102.00  144
 13  \w     32.00 135.00   0.50   11.00    --  101.06-158.00 -52.00  206
 14  \w     77.00 165.00   0.50   11.00    --  101.06 119.00-172.00  176
 15  \w    -43.00  27.00   0.50    5.00    --  -39.33  38.00 150.00  140
 16  \w    -43.00  27.00   0.50    5.00    --  -39.33  38.00 150.00  140
 17  \w    -56.00  27.00   0.50    5.00    --  -39.33  50.00  60.00  166
 18  \w   -109.00 -25.00   0.50    5.00    --  -39.33 -25.00 120.00  168
 19  \w    -31.00  31.00   0.50    5.00    --  -39.33  25.00-150.00  124
 20  \w    -79.00  -2.00   0.50    5.00    --  -39.33 112.00 -90.00  154
 21  \w    -43.00 -10.00   0.50    5.00    --  -39.33 -84.00 -12.71   66
 22  \w    -31.00  31.00   0.50    5.00    --  -39.33  25.00 -60.00  124
 23  \w   -107.00 -16.00   0.50    5.00    --  -39.33 -64.00 120.00  182
 24  \w   -107.00 -16.00   0.50    5.00    --  -39.33 -64.00 120.00  182
 25  \w   -114.00 -41.00   0.50    5.00    --  -39.33-178.00-120.00  146
 26  \w    -43.00 -10.00   0.50    5.00    --  -39.33 -83.00 -70.72   66
 27  \w    -43.00  -9.00   0.50    5.00    --  -39.33 -87.00  88.59   68
 28  \w    -79.00  -2.00   0.50    5.00    --  -39.33 112.00 -90.00  154
 29  \w    -43.00 -11.00   0.50    5.00    --  -39.33 -81.00-118.62   64
 30  \w   -114.00 -41.00   0.50    5.00    --  -39.33-178.00-120.00  146
 31  \w     20.00 106.00   0.50    5.00    --   39.33  50.00  60.00  172
 32  \w     20.00 106.00   0.50    5.00    --   39.33  50.00  60.00  172
 33  \w    -27.00  43.00   0.50    5.00    --   39.33 -38.00 -90.00  140
 34  \w    -32.00  72.00   0.50    5.00    --   39.33 -92.00 -60.00  208
 35  \w    -32.00  72.00   0.50    5.00    --   39.33 -92.00 -60.00  208
 36  \w      9.00  43.00   0.50    5.00    --   39.33  88.00 129.96   68
 37  \w    -36.00  24.00   0.50    5.00    --   39.33 -12.00 -30.00  120
 38  \w    -36.00  24.00   0.50    5.00    --   39.33 -12.00 150.00  120
 39  \w      7.00  35.00   0.50    5.00    --   39.33  93.00 175.76   56
 40  \w    -23.00   3.00   0.50    5.00    --   39.33 -12.00-180.00   52
 41  \w      8.00  39.00   0.50    5.00    --   39.33  89.00 151.21   62
 42  \w     12.00  43.00   0.50    5.00    --   39.33  78.00-142.90   62
 43  \w   -168.00-124.00   0.50   11.00    -- -101.06 -50.00 -90.00   88
 44  \w   -163.00 -87.00   0.50   11.00    -- -101.06 -33.00 -30.00  152
 45  \w    -68.00 -41.00   0.50   11.00    -- -101.06  59.00 -60.00   54
 46  \w    -67.00 -35.00   0.50   11.00    -- -101.06 145.00-150.00   64
 47  \w   -101.00 -75.00   0.50   11.00    -- -101.06  96.00-180.00   52
 48  \w   -121.00 -91.00   0.50   11.00    -- -101.06 -33.00 -90.00   60
 49  \w   -126.00 -79.00   0.50   11.00    -- -101.06 145.00-150.00   94
 50  \w   -168.00-142.00   0.50   11.00    -- -101.06 -33.00 -60.00   52
 51  \w    -68.00 -43.00   0.50   11.00    -- -101.06  59.00   0.00   50
 52  \w    -94.00 -37.00   0.50   11.00    -- -101.06 117.00 120.00  114
 53  \w   -153.00-109.00   0.50   11.00    -- -101.06 -96.00  60.00   88
 54  \w    -83.00 -46.00   0.50   11.00    -- -101.06  68.00  30.00   74
 55  \w   -166.00 -87.00   0.50   11.00    -- -101.06 -42.00  60.00  158
 56  \w   -138.00 -81.00   0.50   11.00    -- -101.06 -54.00  29.58  114
 57  \w   -166.00-140.00   0.50   11.00    -- -101.06 -54.00  29.58   52
 58  \w   -110.00 -37.00   0.50   11.00    -- -101.06 117.00   0.00  146
 59  \w    -81.00 -33.00   0.50   11.00    -- -101.06  68.00   0.00   96
 60  \w   -100.00 -36.00   0.50   11.00    -- -101.06  96.00  90.00  128
 61  \w   -100.00 -39.00   0.50   11.00    -- -101.06 117.00-150.00  122
 62  \w    -68.00 -33.00   0.50   11.00    -- -101.06  59.00 -30.00   70
 63  \w    -68.00 -33.00   0.50   11.00    -- -101.06  59.00 120.00   70
 64  \w   -124.00 -98.00   0.50   11.00    -- -101.06 -33.00 -60.00   52
 65  \w    -53.00 -28.00   0.50   11.00    -- -101.06  96.00   0.00   50
 66  \w    -68.00 -33.00   0.50   11.00    -- -101.06  59.00-120.00   70
 67  \w   -105.00 -63.00   0.50   11.00    -- -101.06  96.00   0.00   84
 68  \w   -127.00 -34.00   0.50   11.00    -- -101.06 145.00 120.00  186
 69  \w    -65.00 -37.00   0.50   11.00    -- -101.06 145.00  60.00   56
 70  \w   -127.00-102.00   0.50   11.00    -- -101.06 145.00  60.00   50
 71  \w    -65.00 -39.00   0.50   11.00    -- -101.06  68.00-180.00   52
 72  \w   -116.00 -90.00   0.50   11.00    -- -101.06 -50.00 -90.00   52
 73  \w   -129.00-104.00   0.50   11.00    -- -101.06-158.00 -52.00   50
 74  \w   -105.00 -37.00   0.50   11.00    -- -101.06 117.00  90.00  136
 75  \w     74.00 169.00   0.50   11.00    --  101.06  77.00-120.00  190
 76  \w    142.00 168.00   0.50   11.00    --  101.06  68.00 120.00   52
 77  \w     75.00 161.00   0.50   11.00    --  101.06  77.00  90.00  172
 78  \w     38.00  85.00   0.50   11.00    --  101.06 -77.00 -90.00   94
 79  \w    103.00 129.00   0.50   11.00    --  101.06  68.00-150.00   52
 80  \w     49.00  75.00   0.50   11.00    --  101.06 -68.00 -90.00   52
 81  \w     85.00 110.00   0.50   11.00    --  101.06  42.00-180.00   50
 82  \w     36.00  61.00   0.50   11.00    --  101.06 -59.00 120.00   50
 83  \w     34.00  68.00   0.50   11.00    --  101.06 -59.00   0.00   68
 84  \w     82.00 168.00   0.50   11.00    --  101.06  50.00 150.00  172
 85  \w     75.00 106.00   0.50   11.00    --  101.06 158.00 -18.00   62
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type
'XtaLAB Synergy, Single source at home/near, HyPix3000'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      0.0050861000
_diffrn_orient_matrix_UB_12      -0.0736569000
_diffrn_orient_matrix_UB_13      0.0476600000
_diffrn_orient_matrix_UB_21      -0.0035038000
_diffrn_orient_matrix_UB_22      -0.1047303000
_diffrn_orient_matrix_UB_23      -0.0335009000
_diffrn_orient_matrix_UB_31      0.1083955000
_diffrn_orient_matrix_UB_32      0.0000590000
_diffrn_orient_matrix_UB_33      0.0075071000
_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  0.0525
_diffrn_reflns_av_unetI/netI     0.0181
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       32
_diffrn_reflns_limit_l_min       -32
_diffrn_reflns_number            71963
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.999
_diffrn_reflns_theta_full        69.993
_diffrn_reflns_theta_max         69.993
_diffrn_reflns_theta_min         3.115
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'PhotonJet (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    12.782
_exptl_absorpt_correction_T_max  0.969
_exptl_absorpt_correction_T_min  0.092
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.41.115a (Rigaku Oxford Diffraction, 2021)
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            red
_exptl_crystal_density_diffrn    1.488
_exptl_crystal_description       prism
_exptl_crystal_F_000             2048
_exptl_crystal_size_max          0.26
_exptl_crystal_size_mid          0.19
_exptl_crystal_size_min          0.06
_refine_diff_density_max         1.240
_refine_diff_density_min         -1.062
_refine_diff_density_rms         0.066
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.042
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     547
_refine_ls_number_reflns         8640
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.042
_refine_ls_R_factor_all          0.0308
_refine_ls_R_factor_gt           0.0299
_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^)+(0.0491P)^2^+2.5984P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0829
_refine_ls_wR_factor_ref         0.0835
_reflns_Friedel_coverage         0.000
_reflns_number_gt                8286
_reflns_number_total             8640
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5cc06477e2.cif
_cod_data_source_block           sb067_5_auto_smart_abs
_cod_database_code               7135310
_shelx_shelxl_version_number     2019/3
_chemical_oxdiff_formula         'C27 H25 Cs N2'
_chemical_oxdiff_usercomment     'CSD: EMEHAG'
_shelx_estimated_absorpt_t_max   0.514
_shelx_estimated_absorpt_t_min   0.136
_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.a Secondary CH2 refined with riding coordinates:
 C4(H4A,H4B), C5(H5A,H5B), C31(H31A,H31B), C32(H32A,H32B)
2.b Aromatic/amide H refined with riding coordinates:
 C2(H2), C3(H3), C11(H11), C12(H12), C13(H13), C14(H14), C15(H15), C16(H16),
 C17(H17), C18(H18), C21(H21), C23(H23), C29(H29), C30(H30), C35(H35), C36(H36),
  C37(H37), C38(H38), C41(H41), C42(H42), C43(H43), C44(H44), C48(H48), C50(H50)
2.c Idealised Me refined as rotating group:
 C25(H25A,H25B,H25C), C26(H26A,H26B,H26C), C27(H27A,H27B,H27C), C52(H52A,H52B,
 H52C), C53(H53A,H53B,H53C), C54(H54A,H54B,H54C)
;
_shelx_res_checksum              79795
_shelx_hkl_checksum              22185
_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 2.352
_oxdiff_exptl_absorpt_empirical_full_min 0.504