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_1576436
_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         'C35 H62 Au Br N2 O2'
_chemical_formula_sum            'C35 H62 Au Br N2 O2'
_chemical_formula_weight         819.74
_chemical_properties_physical    Heat-sensitive,Light-sensitive
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2024-11-24
_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                 91.4620(10)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   10.6050(3)
_cell_length_b                   32.8095(10)
_cell_length_c                   11.2301(3)
_cell_measurement_reflns_used    9995
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      24.203
_cell_measurement_theta_min      2.198
_cell_volume                     3906.18(19)
_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_area_resol_mean 8
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type  'three-circle diffractometer'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0772
_diffrn_reflns_av_unetI/netI     0.0352
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.996
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       40
_diffrn_reflns_limit_k_min       -40
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            84631
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.996
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         26.360
_diffrn_reflns_theta_min         1.917
_diffrn_source                   'sealed tube'
_diffrn_source_current           1.0
_diffrn_source_power             0.05
_diffrn_source_voltage           50.0
_exptl_absorpt_coefficient_mu    4.818
_exptl_absorpt_correction_T_max  0.7454
_exptl_absorpt_correction_T_min  0.5332
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.0843 before and 0.0621 after correction.
The Ratio of minimum to maximum transmission is 0.7153.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.394
_exptl_crystal_description       thin
_exptl_crystal_F_000             1664
_exptl_crystal_preparation       Luminescent
_exptl_crystal_size_max          0.15
_exptl_crystal_size_mid          0.1
_exptl_crystal_size_min          0.08
_refine_diff_density_max         1.185
_refine_diff_density_min         -0.770
_refine_diff_density_rms         0.096
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.020
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     248
_refine_ls_number_reflns         7934
_refine_ls_number_restraints     15
_refine_ls_restrained_S_all      1.025
_refine_ls_R_factor_all          0.1024
_refine_ls_R_factor_gt           0.0607
_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^)+(0.0767P)^2^+12.4000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1562
_refine_ls_wR_factor_ref         0.1836
_reflns_Friedel_coverage         0.000
_reflns_number_gt                4881
_reflns_number_total             7934
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc05986k2.cif
_cod_data_source_block           (RO)2NHCEt-AuBr
_cod_depositor_comments
'Adding full bibliography for 1576435--1576436.cif.'
_cod_database_code               1576436
_shelx_shelxl_version_number     2019/3
_shelx_estimated_absorpt_t_max   0.699
_shelx_estimated_absorpt_t_min   0.532
_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
 C25-C24 = C26-C25 = C27-C26 = C28-C27 = C29-C28 = C30-C29 = C31-C30 = C33-C31
 = C33-C32 = C34-C32 = C35-C34
 1.54 with sigma of 0.02
 C18-C17 = C22-C21
 1.6 with sigma of 0.02
 C23-C22 = C22-C21
 1.47 with sigma of 0.02
3. Uiso/Uaniso restraints and constraints
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(C25) = Uanis(C26) = Uanis(C27) = Uanis(C28) = Uanis(C29) = Uanis(C30) =
Uanis(C31) = Uanis(C32) = Uanis(C33) = Uanis(C34) = Uanis(C35)
4.a Secondary CH2 refined with riding coordinates:
 C8(H8A,H8B), C10(H10A,H10B), C12(H12A,H12B), C13(H13A,H13B), C14(H14A,H14B),
 C15(H15A,H15B), C16(H16A,H16B), C17(H17A,H17B), C18(H18A,H18B), C19(H19A,H19B),
  C20(H20A,H20B), C21(H21A,H21B), C22(H22A,H22B), C24(H24A,H24B), C25(H25A,
 H25B), C26(H26A,H26B), C27(H27A,H27B), C28(H28A,H28B), C29(H29A,H29B),
 C30(H30A,H30B), C31(H31A,H31B), C32(H32A,H32B), C33(H33A,H33B), C34(H34A,H34B)
4.b Me refined as rotating group:
 C9(H9A,H9B,H9C), C11(H11A,H11B,H11C), C23(H23A,H23B,H23C), C35(H35A,H35B,H35C)
4.c Aromatic/amide H refined with riding coordinates:
 C3(H3), C6(H6)
;
_shelx_res_checksum              64810
_olex2_submission_special_instructions 'No special instructions were received'