Synergistic n → π* and n<sub>N</sub> → π*<sub>Ar</sub> interactions in C-terminal modified prolines: effect on Xaa-Pro <i>cis</i>/<i>trans</i> equilibrium.
Deka, Jugal Kishore Rai; Borah, Debashree; Das, Paramesh; Sahariah, Biswajit; Vishnoi, Pratap; Sarma, Bani Kanta; Chemical communications (Cambridge, England) 59 (2023) 6080–6083; doi:10.1039/d3cc01494k

data_7131585
_publ_section_title
;
 Synergistic n &#x2192; &#x3c0;* and n<sub>N</sub> &#x2192;
 &#x3c0;*<sub>Ar</sub> interactions in C-terminal modified prolines:
 effect on Xaa-Pro <i>cis</i>/<i>trans</i> equilibrium.
;
_journal_issue                   40
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              6080
_journal_page_last               6083
_journal_paper_doi               10.1039/d3cc01494k
_journal_volume                  59
_journal_year                    2023
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C16 H18 N4 O3'
_chemical_formula_sum            'C16 H18 N4 O3'
_chemical_formula_weight         314.346
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_symmetry_Int_Tables_number      19
_audit_creation_date             2023-02-09
_audit_creation_method
;
Olex2 1.5
(compiled 2022.04.07 svn.rca3783a0 for OlexSys, GUI svn.r6498)
;
_audit_update_record
;
2023-02-09 deposited with the CCDC.	2023-04-20 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   6.8839(4)
_cell_length_b                   14.6506(11)
_cell_length_c                   16.5975(12)
_cell_measurement_reflns_used    3151
_cell_measurement_temperature    297.42
_cell_measurement_theta_max      21.10
_cell_measurement_theta_min      2.78
_cell_volume                     1673.9(2)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'olex2.refine 1.5 (Bourhis et al., 2015)'
_diffrn_ambient_temperature      297.42
_diffrn_measured_fraction_theta_full 0.9983
_diffrn_measured_fraction_theta_max 0.9973
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0492
_diffrn_reflns_av_unetI/netI     0.0619
_diffrn_reflns_Laue_measured_fraction_full 0.9983
_diffrn_reflns_Laue_measured_fraction_max 0.9973
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       20
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            19160
_diffrn_reflns_point_group_measured_fraction_full 0.9987
_diffrn_reflns_point_group_measured_fraction_max 0.9889
_diffrn_reflns_theta_full        25.2417
_diffrn_reflns_theta_max         30.54
_diffrn_reflns_theta_min         2.78
_diffrn_source                   X-ray
_exptl_absorpt_coefficient_mu    0.089
_exptl_absorpt_correction_T_max  0.7461
_exptl_absorpt_correction_T_min  0.6740
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.247
_exptl_crystal_description       Plate
_exptl_crystal_F_000             664.464
_exptl_crystal_size_max          0.168
_exptl_crystal_size_mid          0.12
_exptl_crystal_size_min          0.023
_refine_diff_density_max         0.2595
_refine_diff_density_min         -0.2269
_refine_diff_density_rms         0.0606
_refine_ls_abs_structure_details
'Hooft, R.W.W., Straver, L.H., Spek, A.L. (2010). J. Appl. Cryst., 43, 665-668.'
_refine_ls_abs_structure_Flack   -0.7(9)
_refine_ls_d_res_high            0.6994
_refine_ls_d_res_low             7.3253
_refine_ls_extinction_coef       0.045(8)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_goodness_of_fit_ref   1.1442
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_constraints    44
_refine_ls_number_parameters     221
_refine_ls_number_reflns         5060
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.1442
_refine_ls_R_factor_all          0.1563
_refine_ls_R_factor_gt           0.0495
_refine_ls_shift/su_max          0.0007
_refine_ls_shift/su_mean         0.0000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0763P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1235
_refine_ls_wR_factor_ref         0.1990
_reflns_Friedel_coverage         0.978
_reflns_limit_h_max              9
_reflns_limit_h_min              -9
_reflns_limit_k_max              20
_reflns_limit_k_min              -20
_reflns_limit_l_max              23
_reflns_limit_l_min              -23
_reflns_number_gt                2099
_reflns_number_total             5060
_reflns_threshold_expression     I>=2u(I)
_cod_data_source_file            d3cc01494k2.cif
_cod_data_source_block           pro_c(o)-nh_nme-c(o)phCN_a
_cod_depositor_comments
'Adding full bibliography for 7131582--7131585.cif.'
_cod_original_sg_symbol_Hall     ' P 2ac 2ab'
_cod_database_code               7131585
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups, All N(H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2. Uiso/Uaniso restraints and constraints
Uanis(C3a) = Uanis(C3b)
Uanis(C4a) = Uanis(C4b)
Uanis(C5a) = Uanis(C5b)
3. Others
 Sof(H6b)=Sof(C5b)=Sof(H5ba)=Sof(H5bb)=Sof(C3b)=Sof(H3ba)=Sof(H3bb)=Sof(C4b)=
 Sof(H4ba)=Sof(H4bb)=1-FVAR(1)
 Sof(H6a)=Sof(C3a)=Sof(H3aa)=Sof(H3ab)=Sof(C4a)=Sof(H4aa)=Sof(H4ab)=Sof(C5a)=
 Sof(H5aa)=Sof(H5ab)=FVAR(1)
4.a Ternary CH refined with riding coordinates:
 C6(H6a), C6(H6b)
4.b Secondary CH2 refined with riding coordinates:
 C3a(H3aa,H3ab), C4a(H4aa,H4ab), C5a(H5aa,H5ab), C5b(H5ba,H5bb), C3b(H3ba,
 H3bb), C4b(H4ba,H4bb)
4.c Aromatic/amide H refined with riding coordinates:
 N2(H2), C14(H14), C15(H15), C11(H11), C12(H12)
4.d Idealised Me refined as rotating group:
 C8(H8a,H8b,H8c), C1(H1a,H1b,H1c)
;
_olex2_submission_special_instructions 'No special instructions were received'