Planarisation or a twist? Using steric engineering to unlock the origin of mechanofluorochromic red-shifts.
McDonald, Peter W.; Goerigk, Lars; Ritchie, Chris; Chemical science 16 (2025) 15320–15332; doi:10.1039/d5sc04257g

data_1575185
_publ_section_title
;
 Planarisation or a twist? Using steric engineering to unlock the origin
 of mechanofluorochromic red-shifts.
;
_journal_issue                   34
_journal_name_full               'Chemical science'
_journal_page_first              15320
_journal_page_last               15332
_journal_paper_doi               10.1039/d5sc04257g
_journal_volume                  16
_journal_year                    2025
_chemical_formula_moiety         'C19 H18 N2'
_chemical_formula_sum            'C19 H18 N2'
_chemical_formula_weight         274.35
_chemical_name_systematic        3,5-dimethyl-N,N-diphenylpyridin-4-amine
_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
_atom_sites_solution_primary     dual
_audit_creation_date             2025-05-25
_audit_creation_method
;
Olex2 1.5
(compiled 2025.04.05 svn.rf049d14d for OlexSys, GUI svn.r7224)
;
_audit_update_record
;
2025-06-06 deposited with the CCDC.	2025-07-18 downloaded from the CCDC.
;
_cell_angle_alpha                87.730(2)
_cell_angle_beta                 85.797(2)
_cell_angle_gamma                62.356(2)
_cell_formula_units_Z            4
_cell_length_a                   9.1685(2)
_cell_length_b                   9.4713(2)
_cell_length_c                   19.6236(4)
_cell_measurement_reflns_used    17957
_cell_measurement_temperature    123.00(10)
_cell_measurement_theta_max      79.9950
_cell_measurement_theta_min      4.4990
_cell_volume                     1505.45(6)
_computing_cell_refinement       'CrysAlisPro 1.171.42.70a (Rigaku OD, 2022)'
_computing_data_collection       'CrysAlisPro 1.171.42.70a (Rigaku OD, 2022)'
_computing_data_reduction        'CrysAlisPro 1.171.42.70a (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 2019/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      123.00(10)
_diffrn_detector                 'Hybrid Pixel Array Detector'
_diffrn_detector_area_resol_mean 10.0000
_diffrn_detector_type            HyPix
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.974
_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   -122.00 -61.00   0.50    1.26    --  -50.51-143.00 -63.00  122
  2  \w   -120.00 -72.00   0.50    1.26    --  -50.51-127.00 106.00   96
  3  \w    -87.00 -14.00   0.50    1.26    --  -50.51 127.00-178.00  146
  4  \w    -99.00 -22.00   0.50    1.26    --  -50.51 143.00  -8.00  154
  5  \w     36.00  95.00   0.50    1.26    --   50.51-127.00 106.00  118
  6  \w     44.00 106.00   0.50    1.26    --   50.51-143.00 -63.00  124
  7  \w    -87.00 -20.00   0.50    5.04    --  -90.00 127.00-178.00  134
  8  \w   -155.00 -61.00   0.50    5.04    --  -90.00-143.00 -63.00  188
  9  \w   -160.00 -72.00   0.50    5.04    --  -90.00-127.00 106.00  176
 10  \w    -99.00 -22.00   0.50    5.04    --  -90.00 143.00  -8.00  154
 11  \w     83.00 171.00   0.50    5.04    --  111.50 143.00  -8.00  176
 12  \w     94.00 178.00   0.50    5.04    --  111.50 127.00-178.00  168
 13  \w     44.00 125.00   0.50    5.04    --  111.50-143.00 -63.00  162
 14  \w     42.00 113.00   0.50    5.04    --  111.50-127.00 106.00  142
 15  \w   -122.00 -39.00   0.50    1.26    --  -50.51 -57.00-180.00  166
 16  \w    -55.00  21.00   0.50    1.26    --  -50.51  19.00 -30.00  152
 17  \w    -99.00 -44.00   0.50    1.26    --  -50.51   0.00-150.00  110
 18  \w     31.00 122.00   0.50    1.26    --   50.51  77.00 120.00  182
 19  \w    -68.00 -17.00   0.50    5.04    --  -90.00  30.00  60.00  102
 20  \w     40.00  66.00   0.50    5.04    --  111.50 -30.00  60.00   52
 21  \w     40.00  66.00   0.50    5.04    --  111.50 -30.00 150.00   52
 22  \w     41.00  76.00   0.50    5.04    --  111.50 -45.00 120.00   70
 23  \w     41.00 106.00   0.50    5.04    --  111.50 -94.00 -30.00  130
 24  \w     41.00 106.00   0.50    5.04    --  111.50 -94.00 150.00  130
 25  \w     63.00 118.00   0.50    5.04    --  111.50   0.00  60.00  110
 26  \w     40.00  66.00   0.50    5.04    --  111.50 -30.00 -30.00   52
 27  \w     41.00 106.00   0.50    5.04    --  111.50 -94.00 -90.00  130
 28  \w     40.00 116.00   0.50    5.04    --  111.50 -15.00  30.00  152
 29  \w     40.00  66.00   0.50    5.04    --  111.50 -30.00  30.00   52
 30  \w     40.00  66.00   0.50    5.04    --  111.50 -30.00 120.00   52
 31  \w     41.00 131.00   0.50    5.04    --  111.50 -77.00  30.00  180
 32  \w     67.00 116.00   0.50    5.04    --  111.50   0.00 -60.00   98
 33  \w     44.00 105.00   0.50    5.04    --  111.50-125.00-120.00  122
 34  \w     42.00  73.00   0.50    5.04    --  111.50 -45.00  30.00   62
 35  \w     58.00 106.00   0.50    5.04    --  111.50 -94.00 120.00   96
 36  \w     93.00 118.00   0.50    5.04    --  111.50  77.00   0.00   50
 37  \w    128.00 163.00   0.50    5.04    --  111.50  77.00   0.00   70
 38  \w     74.00 118.00   0.50    5.04    --  111.50   0.00   0.00   88
 39  \w     44.00  79.00   0.50    5.04    --  111.50-125.00 -60.00   70
 40  \w     86.00 111.00   0.50    5.04    --  111.50-125.00 -60.00   50
 41  \w     49.00 110.00   0.50    5.04    --  111.50-125.00  90.00  122
 42  \w     40.00  65.00   0.50    5.04    --  111.50 -30.00 -60.00   50
 43  \w     46.00  76.00   0.50    5.04    --  111.50 -45.00-120.00   60
 44  \w     49.00 125.00   0.50    5.04    --  111.50 -61.00-180.00  152
 45  \w     45.00 104.00   0.50    5.04    --  111.50 -94.00   0.00  118
 46  \w     46.00  72.00   0.50    5.04    --  111.50 -45.00  90.00   52
 47  \w     43.00  70.00   0.50    5.04    --  111.50 -45.00 -90.00   54
 48  \w    108.00 154.00   0.50    5.04    --  111.50  15.00   0.00   92
 49  \w     96.00 122.00   0.50    5.04    --  111.50 125.00-150.00   52
 50  \w    137.00 163.00   0.50    5.04    --  111.50 125.00-150.00   52
 51  \w     49.00  75.00   0.50    5.04    --  111.50 -94.00-180.00   52
 52  \w     41.00  96.00   0.50    5.04    --  111.50 -94.00 -60.00  110
 53  \w     40.00  66.00   0.50    5.04    --  111.50 -30.00-150.00   52
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'XtaLAB Synergy, Dualflex, HyPix'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      0.0936710000
_diffrn_orient_matrix_UB_12      0.0263022000
_diffrn_orient_matrix_UB_13      -0.0635835000
_diffrn_orient_matrix_UB_21      0.1204834000
_diffrn_orient_matrix_UB_22      0.0157271000
_diffrn_orient_matrix_UB_23      0.0461683000
_diffrn_orient_matrix_UB_31      0.1132558000
_diffrn_orient_matrix_UB_32      -0.1810434000
_diffrn_orient_matrix_UB_33      -0.0047209000
_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  0.0334
_diffrn_reflns_av_unetI/netI     0.0271
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.974
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            31844
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.974
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         80.337
_diffrn_reflns_theta_min         4.519
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'PhotonJet (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    0.549
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.96730
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.42.70a (Rigaku Oxford Diffraction, 2022)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            'clear yellowish yellow'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_modifier   yellowish
_exptl_crystal_colour_primary    yellow
_exptl_crystal_density_diffrn    1.210
_exptl_crystal_description       plate
_exptl_crystal_F_000             584
_exptl_crystal_preparation       oil
_exptl_crystal_recrystallization_method dichloromethane/methanol
_exptl_crystal_size_max          0.15
_exptl_crystal_size_mid          0.04
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.231
_refine_diff_density_min         -0.185
_refine_diff_density_rms         0.038
_refine_ls_extinction_coef       0.0022(3)
_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   1.126
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     384
_refine_ls_number_reflns         6427
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.126
_refine_ls_R_factor_all          0.0443
_refine_ls_R_factor_gt           0.0395
_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^)+(0.0258P)^2^+0.7173P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0995
_refine_ls_wR_factor_ref         0.1015
_reflns_Friedel_coverage         0.000
_reflns_number_gt                5793
_reflns_number_total             6427
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc04257g2.cif
_cod_data_source_block           pm3_22_dcm_meoh_b_auto
_cod_depositor_comments
'Adding full bibliography for 1575172--1575185.cif.'
_cod_database_code               1575185
_shelx_shelxl_version_number     2019/3
_chemical_oxdiff_formula         C19H18N2
_shelx_estimated_absorpt_t_max   0.989
_shelx_estimated_absorpt_t_min   0.922
_diffrn_oxdiff_digest_hkl
;
0152bce3b3448cef7944151091e05ff490a977
;
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Aromatic/amide H refined with riding coordinates:
 C4(H4), C31(H31), C27(H27), C12(H12), C2(H2), C8(H8), C28(H28), C30(H30),
 C5(H5), C23(H23), C29(H29), C9(H9), C11(H11), C21(H21), C1(H1), C15(H15),
 C35(H35), C16(H16), C10(H10), C34(H34), C24(H24), C6(H6), C20(H20), C25(H25)
2.b Idealised Me refined as rotating group:
 C19(H19A,H19B,H19C), C37(H37A,H37B,H37C), C18(H18A,H18B,H18C), C38(H38A,H38B,
 H38C)
;
_shelx_res_checksum              24176
_olex2_exptl_crystal_mounting_method oil
_olex2_submission_original_sample_id '5 123 K'
_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 1.940
_oxdiff_exptl_absorpt_empirical_full_min 0.773