Beyond wingtips: backbone alkylation affects the orientation of N-heterocyclic carbenes on gold nanoparticles.
Nezamzadeh, Ahmadreza; Chowdhury, Shayanta; Hu, Gaohe; Dominique, Nathaniel L.; Desroche, Emmett; Hossain, Sakiat; Aloisio, Mark D.; Furlan, Michael; Groome, Ryan R. K.; Boire, Kayla; McLean, Alastair B.; Jensen, Lasse; Camden, Jon P.; Crudden, Cathleen M.; Chemical science 17 (2026) 6717–6726; doi:10.1039/d5sc05986k

data_1576435
_publ_section_title
;
 Beyond wingtips: backbone alkylation affects the orientation of
 N-heterocyclic carbenes on gold nanoparticles.
;
_journal_issue                   13
_journal_name_full               'Chemical science'
_journal_page_first              6717
_journal_page_last               6726
_journal_paper_doi               10.1039/d5sc05986k
_journal_volume                  17
_journal_year                    2026
_chemical_formula_moiety         'C37 H66 Au Br N2 O2'
_chemical_formula_sum            'C37 H66 Au Br N2 O2'
_chemical_formula_weight         847.79
_chemical_properties_physical    Heat-sensitive,Light-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
_atom_sites_solution_primary     dual
_audit_creation_date             2024-12-13
_audit_creation_method
;
Olex2 1.5
(compiled 2024.02.16 svn.r378c4104 for OlexSys, GUI svn.r6928)
;
_audit_update_record
;
2025-02-26 deposited with the CCDC.	2026-01-12 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 97.069(3)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   10.6121(5)
_cell_length_b                   11.5625(7)
_cell_length_c                   32.624(2)
_cell_measurement_reflns_used    4560
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      18.576
_cell_measurement_theta_min      2.164
_cell_volume                     3972.6(4)
_computing_cell_refinement       'SAINT V8.40B (?, 2016)'
_computing_data_reduction        'SAINT V8.40B (?, 2016)'
_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_temperature      298.00
_diffrn_detector                 'Bruker APEX2 area detector'
_diffrn_detector_type            'CCD area detector'
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device       'three-circle diffractometer'
_diffrn_radiation_monochromator  'mirror optics'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.1826
_diffrn_reflns_av_unetI/netI     0.0603
_diffrn_reflns_Laue_measured_fraction_full 0.997
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            53212
_diffrn_reflns_point_group_measured_fraction_full 0.997
_diffrn_reflns_point_group_measured_fraction_max 0.997
_diffrn_reflns_theta_full        18.958
_diffrn_reflns_theta_max         18.958
_diffrn_reflns_theta_min         1.870
_diffrn_source_current           1.0
_diffrn_source_power             0.05
_diffrn_source_type              'Incoatec I\ms'
_diffrn_source_voltage           50.0
_exptl_absorpt_coefficient_mu    4.740
_exptl_absorpt_correction_T_max  0.5585
_exptl_absorpt_correction_T_min  0.3642
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1271 before and 0.1121 after correction.
The Ratio of minimum to maximum transmission is 0.6521.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.417
_exptl_crystal_description       plate
_exptl_crystal_F_000             1728
_exptl_crystal_preparation       Luminescent
_exptl_crystal_size_max          0.139
_exptl_crystal_size_mid          0.12
_exptl_crystal_size_min          0.05
_refine_diff_density_max         1.883
_refine_diff_density_min         -1.174
_refine_diff_density_rms         0.186
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.092
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     172
_refine_ls_number_reflns         3174
_refine_ls_number_restraints     35
_refine_ls_restrained_S_all      1.090
_refine_ls_R_factor_all          0.1166
_refine_ls_R_factor_gt           0.0802
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0935P)^2^+90.5774P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2019
_refine_ls_wR_factor_ref         0.2329
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2239
_reflns_number_total             3174
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc05986k2.cif
_cod_data_source_block           (RO)2NHCiPr-AuBr
_cod_depositor_comments
'Adding full bibliography for 1576435--1576436.cif.'
_cod_database_code               1576435
_shelx_shelxl_version_number     2019/3
_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. Restrained distances
 C2-C1 = C3-C2 = C4-C3 = C5-C4 = C6-C5 = C7-C6 = C8-C7 = C9-C8 = C9-C10 = C11-
 C10 = C12-C11
 1.54 with sigma of 0.02
 O2-C13 = C14-C13 = C15-C14 = C16-C15 = C17-C16 = C18-C17 = C19-C18 = C20-C19 =
  C21-C20 = C22-C21 = C23-C22 = C24-C23
 1.54 with sigma of 0.02
3. Uiso/Uaniso restraints and constraints
Uanis(N2) \\sim Ueq, Uanis(N1) \\sim Ueq: with sigma of 0.01 and sigma for
terminal atoms of 0.05
Uanis(C1) = Uanis(C8) = Uanis(C15) = Uanis(C19) = Uanis(C21) = Uanis(C33) =
Uanis(C17) = Uanis(C34) = Uanis(C14) = Uanis(C9) = Uanis(C16) = Uanis(C18) =
Uanis(C5) = Uanis(C20) = Uanis(C10) = Uanis(C7) = Uanis(C22) = Uanis(C3) =
Uanis(C4) = Uanis(C24) = Uanis(C6) = Uanis(C2) = Uanis(C12)
Uanis(C13) = Uanis(C35) = Uanis(C1) = Uanis(C8) = Uanis(C15) = Uanis(C19) =
Uanis(C21) = Uanis(C33) = Uanis(C17) = Uanis(C34) = Uanis(C14) = Uanis(C9) =
Uanis(C16) = Uanis(C18) = Uanis(C5) = Uanis(C20) = Uanis(C10) = Uanis(C7) =
Uanis(C22) = Uanis(C3) = Uanis(C4) = Uanis(C24)
Uanis(C1) = Uanis(C2) = Uanis(C3) = Uanis(C4) = Uanis(C5) = Uanis(C6) =
Uanis(C7) = Uanis(C8) = Uanis(C9) = Uanis(C10) = Uanis(C11) = Uanis(C12)
Uanis(C13) = Uanis(C14) = Uanis(C15) = Uanis(C16) = Uanis(C17) = Uanis(C18) =
Uanis(C19) = Uanis(C20) = Uanis(C21) = Uanis(C22) = Uanis(C23) = Uanis(C24)
Uanis(C26) = Uanis(C27) = Uanis(C28) = Uanis(C29) = Uanis(C30) = Uanis(C25)
Uanis(C32) = Uanis(C34) = Uanis(C33) = Uanis(C37) = Uanis(C36) = Uanis(C35)
Uanis(O2) = Uanis(O1)
4.a Ternary CH refined with riding coordinates:
 C32(H32), C35(H35)
4.b Secondary CH2 refined with riding coordinates:
 C23(H23A,H23B), C13(H13A,H13B), C1(H1A,H1B), C8(H8A,H8B), C15(H15A,H15B),
 C19(H19A,H19B), C21(H21A,H21B), C17(H17A,H17B), C14(H14A,H14B), C9(H9A,H9B),
 C16(H16A,H16B), C18(H18A,H18B), C5(H5A,H5B), C20(H20A,H20B), C10(H10A,H10B),
 C7(H7A,H7B), C22(H22A,H22B), C3(H3A,H3B), C4(H4A,H4B), C6(H6A,H6B), C2(H2A,
 H2B), C11(H11A,H11B)
4.c Aromatic/amide H refined with riding coordinates:
 C27(H27), C30(H30)
4.d Fitted hexagon refined as free rotating group:
 C27(C28,C29,C30,C25,C26)
4.e Idealised Me refined as rotating group:
 C36(H36A,H36B,H36C), C37(H37A,H37B,H37C), C33(H33A,H33B,H33C), C34(H34A,H34B,
 H34C), C24(H24A,H24B,H24C), C12(H12A,H12B,H12C)
;
_shelx_res_checksum              18873
_olex2_submission_special_instructions 'No special instructions were received'