Amidines: a deeper look at the archetypal pro-ligand.
de Vere-Tucker, Matthew; Squire, Imogen; Tritto, Michelangelo; Anandkar, Rohil; Syeda, Tayyibah; Uthayan, Divia; Aguila, Gabrielle; Silva de Moraes, Lygia; Bakewell, Clare; Dalton transactions (Cambridge, England : 2003) 55 (2026) 4977–4987; doi:10.1039/d6dt00276e

data_7720569
_publ_section_title
;
 Amidines: a deeper look at the archetypal pro-ligand.
;
_journal_issue                   12
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              4977
_journal_page_last               4987
_journal_paper_doi               10.1039/d6dt00276e
_journal_volume                  55
_journal_year                    2026
_chemical_formula_moiety         'C70 H95 Al N4, 1[C6H14]'
_chemical_formula_sum            'C76 H109 Al N4'
_chemical_formula_weight         1105.65
_chemical_properties_physical    Air-sensitive,Moisture-sensitive
_space_group_crystal_system      monoclinic
_space_group_IT_number           7
_space_group_name_Hall           'P -2yac'
_space_group_name_H-M_alt        'P 1 n 1'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     dual
_audit_creation_date             2026-01-05
_audit_creation_method
;
Olex2 1.5
(compiled 2025.07.13 svn.rb7424aed for OlexSys, GUI svn.r7314)
;
_audit_update_record
;
2026-01-30 deposited with the CCDC.	2026-03-03 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 96.842(2)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   12.0013(3)
_cell_length_b                   21.8264(6)
_cell_length_c                   13.1336(3)
_cell_measurement_reflns_used    10075
_cell_measurement_temperature    100.00(10)
_cell_measurement_theta_max      74.0060
_cell_measurement_theta_min      2.1280
_cell_volume                     3415.78(15)
_computing_cell_refinement       'CrysAlisPro 1.171.44.118a (Rigaku OD, 2025)'
_computing_data_collection
'CrysAlisPro system (CCD 44.127a 64-bit (release 27-10-2025))'
_computing_data_reduction        'CrysAlisPro 1.171.44.118a (Rigaku OD, 2025)'
_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      100.00(10)
_diffrn_detector                 'Hybrid Pixel Array Detector'
_diffrn_detector_area_resol_mean 10.0000
_diffrn_detector_type            'HyPix-Arc 100'
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.991
_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    -99.00   6.00   0.50    2.00    --  -51.92 117.00-163.00  210
  2  \w   -124.00 -26.00   0.50    2.00    --  -51.92 165.00 -15.00  196
  3  \w   -155.00 -50.00   0.50    2.00    --  -87.65-165.00 -38.00  210
  4  \w   -142.00 -83.00   0.50    2.00    --  -87.65-117.00 109.00  118
  5  \w     40.00  65.00   0.50    2.00    --   93.27-117.00 109.00   50
  6  \w    102.00 127.00   0.50    2.00    --   93.27 117.00-163.00   50
  7  \w     61.00  86.00   0.50    2.00    --   93.27-165.00 -38.00   50
  8  \w    -14.00  11.00   0.50    2.00    --   28.00 110.00  44.76   50
  9  \w   -116.00 -78.00   0.50    2.00    --  -51.92 -77.00 -30.00   76
 10  \w    -21.00  21.00   0.50    2.00    --  -51.92  19.00-150.00   84
 11  \w   -119.00 -75.00   0.50    2.00    --  -51.92 -77.00 120.00   88
 12  \w     85.00 111.00   0.50    2.00    --   93.27-125.00-150.00   52
 13  \w     27.00  69.00   0.50    2.00    --   93.27-125.00-150.00   84
 14  \w     54.00 110.00   0.50    2.00    --   93.27-125.00 150.00  112
 15  \w     18.00  54.00   0.50    2.00    --   93.27 -45.00 -30.00   72
 16  \w     19.00  47.00   0.50    2.00    --   93.27 -45.00 -60.00   56
 17  \w     18.00  53.00   0.50    2.00    --   93.27 -45.00-120.00   70
 18  \w   -112.00 -77.00   0.50    2.00    --  -96.00 132.00 166.36   70
 19  \w   -110.00 -84.00   0.50    2.00    --  -96.00 124.00 153.15   52
 20  \w    146.00 172.00   0.50    2.00    --  100.00  13.00 -28.45   52
 21  \w     79.00 142.00   0.50    2.00    --  100.00  13.00 -28.45  126
 22  \w     70.00  96.00   0.50    2.00    --  100.00  14.00-146.93   52
 23  \w     42.00 101.00   0.50    2.00    --  100.00 -90.00  85.26  118
 24  \w     40.00  70.00   0.50    2.00    --  100.00 -78.00 -70.59   60
 25  \w     33.00  91.00   0.50    2.00    --  100.00 -78.00-108.46  116
 26  \w     32.00  63.00   0.50    2.00    --  100.00 -78.00 112.81   62
 27  \w     44.00  75.00   0.50    2.00    --  100.00 -85.00 -46.16   62
 28  \w     33.00 105.00   0.50    2.00    --  100.00 -88.00 147.99  144
 29  \w     78.00 105.00   0.50    2.00    --  100.00 -90.00  25.88   54
 30  \w     36.00  62.00   0.50    2.00    --  100.00 -90.00  25.88   52
 31  \w     67.00 150.00   0.50    2.00    --  100.00  14.00 -83.10  166
 32  \w     69.00 133.00   0.50    2.00    --  100.00  13.00 137.30  128
 33  \w     75.00 102.00   0.50    2.00    --  100.00 -89.00 127.86   54
 34  \w     35.00  60.00   0.50    2.00    --  100.00 -89.00-109.83   50
 35  \w     33.00  72.00   0.50    2.00    --  100.00 -90.00 -20.52   78
 36  \w     81.00 106.00   0.50    2.00    --  100.00 -90.00 -20.52   50
 37  \w     33.00  63.00   0.50    2.00    --  100.00 -89.00  66.82   60
 38  \w     33.00  63.00   0.50    2.00    --  100.00 -76.00-140.10   60
 39  \w     57.00  97.00   0.50    2.00    --  100.00 -74.00 158.50   80
 40  \w    105.00 131.00   0.50    2.00    --  100.00  14.00-146.93   52
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'XtaLAB Synergy R, DW system, HyPix-Arc 100'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      -0.0594527000
_diffrn_orient_matrix_UB_12      -0.0620374000
_diffrn_orient_matrix_UB_13      -0.0209354000
_diffrn_orient_matrix_UB_21      -0.0935562000
_diffrn_orient_matrix_UB_22      0.0319251000
_diffrn_orient_matrix_UB_23      -0.0714263000
_diffrn_orient_matrix_UB_31      0.0664960000
_diffrn_orient_matrix_UB_32      -0.0107153000
_diffrn_orient_matrix_UB_33      -0.0917672000
_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  0.0391
_diffrn_reflns_av_unetI/netI     0.0374
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.991
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       27
_diffrn_reflns_limit_k_min       -26
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            42481
_diffrn_reflns_point_group_measured_fraction_full 0.787
_diffrn_reflns_point_group_measured_fraction_max 0.760
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         75.679
_diffrn_reflns_theta_min         3.949
_diffrn_source                   'Rotating-anode X-ray tube'
_diffrn_source_type              'Rigaku (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    0.575
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.206
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.44.118a (Rigaku Oxford Diffraction, 2025)
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    1.075
_exptl_crystal_description       block
_exptl_crystal_F_000             1212
_exptl_crystal_recrystallization_method
'Re-crystallisation from solvent: hexane'
_exptl_crystal_size_max          0.47
_exptl_crystal_size_mid          0.31
_exptl_crystal_size_min          0.24
_refine_diff_density_max         0.296
_refine_diff_density_min         -0.263
_refine_diff_density_rms         0.043
_refine_ls_abs_structure_details
;
 Refined as an inversion twin.
;
_refine_ls_abs_structure_Flack   0.64(12)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.065
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     671
_refine_ls_number_reflns         10787
_refine_ls_number_restraints     28
_refine_ls_restrained_S_all      1.076
_refine_ls_R_factor_all          0.0828
_refine_ls_R_factor_gt           0.0666
_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^)+(0.1309P)^2^+0.5417P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1934
_refine_ls_wR_factor_ref         0.2122
_reflns_Friedel_coverage         0.530
_reflns_Friedel_fraction_full    0.573
_reflns_Friedel_fraction_max     0.527
_reflns_number_gt                8433
_reflns_number_total             10787
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d6dt00276e3.cif
_cod_data_source_block           (dippAmptBuPh)2AlH_2-Al''
_cod_depositor_comments
'Adding full bibliography for 7720566--7720581.cif.'
_cod_database_code               7720569
_shelx_shelxl_version_number     2019/3
_chemical_oxdiff_formula         'C11 H10 N O'
_cell_oxdiff_angle_alpha         90.0193(16)
_cell_oxdiff_angle_beta          96.8625(16)
_cell_oxdiff_angle_gamma         89.9290(18)
_cell_oxdiff_length_a            12.0040(3)
_cell_oxdiff_length_b            21.8248(5)
_cell_oxdiff_length_c            13.1322(2)
_cell_oxdiff_measurement_reflns_used 10074
_cell_oxdiff_volume              3415.78(12)
_shelx_estimated_absorpt_t_max   0.874
_shelx_estimated_absorpt_t_min   0.774
_diffrn_oxdiff_digest_od_ed
;

;
_diffrn_oxdiff_measurement_exp_name exp_17_IS429_full.par
_olex2_refinement_description
;
1. Twinned data refinement
 Scales: 0.36(12)
 0.64(12)
2. 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
3. Restrained distances
 Al1-H
 1.52 with sigma of 0.02
 C43-C45 \\sim C43-C44A
 with sigma of 0.02
 C68-C70 \\sim C68-C70A
 with sigma of 0.02
 C43-C44 \\sim C43-C46A
 with sigma of 0.02
 C43-C46 \\sim C43-C45A
 with sigma of 0.02
 C68-C69 \\sim C68-C69A
 with sigma of 0.02
 C1-C2 \\sim C1-C2A
 with sigma of 0.02
 C7-C2 \\sim C7A-C2A
 with sigma of 0.02
 C7-C6 \\sim C7A-C6A
 with sigma of 0.02
 C2-C3 \\sim C2A-C3A
 with sigma of 0.02
 C4-C3 \\sim C4A-C3A
 with sigma of 0.02
 C4-C5 \\sim C4A-C5A
 with sigma of 0.02
 C6-C5 \\sim C6A-C5A
 with sigma of 0.02
 C5-C8 \\sim C5A-C8A
 with sigma of 0.02
 C1-C7 \\sim C1-C7A
 with sigma of 0.04
 C1-C3 \\sim C1-C3A
 with sigma of 0.04
 C7-C3 \\sim C7A-C3A
 with sigma of 0.04
 C7-C5 \\sim C7A-C5A
 with sigma of 0.04
 C2-C4 \\sim C2A-C4A
 with sigma of 0.04
 C2-C6 \\sim C2A-C6A
 with sigma of 0.04
 C4-C6 \\sim C4A-C6A
 with sigma of 0.04
 C4-C8 \\sim C4A-C8A
 with sigma of 0.04
 C3-C5 \\sim C3A-C5A
 with sigma of 0.04
 C6-C8 \\sim C6A-C8A
 with sigma of 0.04
 C56-C57 \\sim C56-C57A
 with sigma of 0.02
 C56-C58 \\sim C56-C58A
 with sigma of 0.02
 C8-C11 \\sim C8-C10A
 with sigma of 0.02
 C8-C10 \\sim C8-C11A
 with sigma of 0.02
 C8-C9 \\sim C8-C9A
 with sigma of 0.02
4. Restrained angles
 C10A-C8A-C9A
 fixed at 60 with sigma of 0.02
 C10A-C8A-C11A
 fixed at 60 with sigma of 0.02
 C10-C8-C9
 fixed at 60 with sigma of 0.02
5. Uiso/Uaniso restraints and constraints
Uanis(C70) = Uanis(C70A) = Uanis(C69A) = Uanis(C69)
Uanis(C54) = Uanis(C55)
Uanis(C46) = Uanis(C44A) = Uanis(C45) = Uanis(C45A) = Uanis(C44) = Uanis(C46A)
Uanis(C2A) = Uanis(C2) = Uanis(C3A) = Uanis(C3) = Uanis(C4A) = Uanis(C4) =
Uanis(C5A) = Uanis(C5) = Uanis(C8) = Uanis(C8A) = Uanis(C6A) = Uanis(C6) =
Uanis(C7A) = Uanis(C7)
Uanis(C57) = Uanis(C58)
Uanis(C58) = Uanis(C58A) = Uanis(C57) = Uanis(C57A)
Uanis(C11A) = Uanis(C9A) = Uanis(C10A) = Uanis(C11) = Uanis(C10) = Uanis(C9)
Uanis(C10A) = Uanis(C11A) = Uanis(C9A) = Uanis(C11) = Uanis(C10) = Uanis(C9)
Uanis(C52) = Uanis(C51) = Uanis(C50) = Uanis(C49) = Uanis(C48) = Uanis(C47)
6. Others
 Sof(C44A)=Sof(H44D)=Sof(H44E)=Sof(H44F)=Sof(C45A)=Sof(H45D)=Sof(H45E)=
 Sof(H45F)=Sof(C46A)=Sof(H46D)=Sof(H46E)=Sof(H46F)=1-FVAR(1)
 Sof(C45)=Sof(H45A)=Sof(H45B)=Sof(H45C)=Sof(C44)=Sof(H44A)=Sof(H44B)=Sof(H44C)=
 Sof(C46)=Sof(H46A)=Sof(H46B)=Sof(H46C)=FVAR(1)
 Sof(H68A)=Sof(C69A)=Sof(H69D)=Sof(H69E)=Sof(H69F)=Sof(C70A)=Sof(H70D)=
 Sof(H70E)=Sof(H70F)=1-FVAR(2)
 Sof(H68)=Sof(C70)=Sof(H70A)=Sof(H70B)=Sof(H70C)=Sof(C69)=Sof(H69A)=Sof(H69B)=
 Sof(H69C)=FVAR(2)
 Sof(C2A)=Sof(C7A)=Sof(H7A)=Sof(C6A)=Sof(H6A)=Sof(C8A)=Sof(C5A)=Sof(C4A)=
 Sof(H4A)=Sof(C3A)=Sof(H3A)=Sof(C11A)=Sof(H11D)=Sof(H11E)=Sof(H11F)=Sof(C10A)=
 Sof(H10D)=Sof(H10E)=Sof(H10F)=Sof(C9A)=Sof(H9AA)=Sof(H9AB)=Sof(H9AC)=1-FVAR(3)
 Sof(C7)=Sof(H7)=Sof(C2)=Sof(C4)=Sof(H4)=Sof(C3)=Sof(H3)=Sof(C6)=Sof(H6)=
 Sof(C5)=Sof(C8)=Sof(C11)=Sof(H11A)=Sof(H11B)=Sof(H11C)=Sof(C10)=Sof(H10A)=
 Sof(H10B)=Sof(H10C)=Sof(C9)=Sof(H9A)=Sof(H9B)=Sof(H9C)=FVAR(3)
 Sof(H56A)=Sof(C58A)=Sof(H58D)=Sof(H58E)=Sof(H58F)=Sof(C57A)=Sof(H57D)=
 Sof(H57E)=Sof(H57F)=1-FVAR(4)
 Sof(H56)=Sof(C57)=Sof(H57A)=Sof(H57B)=Sof(H57C)=Sof(C58)=Sof(H58A)=Sof(H58B)=
 Sof(H58C)=FVAR(4)
 Fixed Sof: Al1A(0.5) Al1(0.5) H(0.5) HA(0.5)
7.a Ternary CH refined with riding coordinates:
 C21(H21), C65(H65), C68(H68), C68(H68A), C53(H53), C56(H56), C56(H56A),
 C30(H30), C33(H33), C18(H18)
7.b Me refined with riding coordinates:
 C54(H54A,H54B,H54C), C70A(H70D,H70E,H70F)
7.c Aromatic/amide H refined with riding coordinates:
 C38(H38), C49(H49), C50(H50), C39(H39), C7(H7), C51(H51), C41(H41), C16(H16),
 C42(H42), C4(H4), C63(H63), C26(H26), C3(H3), C27(H27), C6(H6), C28(H28),
 C61(H61), C15(H15), C14(H14), C62(H62), C7A(H7A), C6A(H6A), C4A(H4A), C3A(H3A)
7.d Idealised Me refined as rotating group:
 C22(H22A,H22B,H22C), C67(H67A,H67B,H67C), C35(H35A,H35B,H35C), C23(H23A,H23B,
 H23C), C32(H32A,H32B,H32C), C31(H31A,H31B,H31C), C34(H34A,H34B,H34C), C55(H55A,
 H55B,H55C), C70(H70A,H70B,H70C), C66(H66A,H66B,H66C), C69(H69A,H69B,H69C),
 C45(H45A,H45B,H45C), C44(H44A,H44B,H44C), C46(H46A,H46B,H46C), C44A(H44D,H44E,
 H44F), C45A(H45D,H45E,H45F), C46A(H46D,H46E,H46F), C69A(H69D,H69E,H69F),
 C11(H11A,H11B,H11C), C10(H10A,H10B,H10C), C9(H9A,H9B,H9C), C57(H57A,H57B,H57C),
  C58(H58A,H58B,H58C), C58A(H58D,H58E,H58F), C57A(H57D,H57E,H57F), C11A(H11D,
 H11E,H11F), C10A(H10D,H10E,H10F), C9A(H9AA,H9AB,H9AC), C19(H19A,H19B,H19C),
 C20(H20A,H20B,H20C)
;
_smtbx_masks_void_probe_radius   1.2
_smtbx_masks_void_truncation_radius 1.2
_shelx_res_checksum              15661
_shelx_hkl_checksum              70344
_shelx_fab_checksum              97137
_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 2.516
_oxdiff_exptl_absorpt_empirical_full_min 0.405