An unnatural tripeptide structure containing intramolecular double H-bonds mimics a turn hairpin conformation.
Liu, Jin-Yu; Sun, Xue-Yi; Tang, Quan; Song, Jun-Jie; Li, Xiao-Qi; Gong, Bing; Liu, Rui; Lu, Zhong-Lin; Organic & biomolecular chemistry 19 (2021) 4359–4363; doi:10.1039/d1ob00526j

data_7158026
_publ_section_title
;
 An unnatural tripeptide structure containing intramolecular double
 H-bonds mimics a turn hairpin conformation.
;
_journal_issue                   19
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              4359
_journal_page_last               4363
_journal_paper_doi               10.1039/d1ob00526j
_journal_volume                  19
_journal_year                    2021
_chemical_formula_moiety         'C34 H49 N4 O9'
_chemical_formula_sum            'C34 H49 N4 O9'
_chemical_formula_weight         657.77
_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             2020-08-26
_audit_creation_method
;
Olex2 1.2
(compiled 2018.05.29 svn.r3508 for OlexSys, GUI svn.r5506)
;
_audit_update_record
;
2021-02-04 deposited with the CCDC.	2021-04-14 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 92.493(18)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   17.858(3)
_cell_length_b                   7.985(2)
_cell_length_c                   24.624(6)
_cell_measurement_reflns_used    5316
_cell_measurement_temperature    200(140)
_cell_measurement_theta_max      75.3360
_cell_measurement_theta_min      3.5820
_cell_volume                     3508.0(14)
_computing_cell_refinement       'CrysAlisPro 1.171.40.67a (Rigaku OD, 2019)'
_computing_data_collection       'CrysAlisPro 1.171.40.67a (Rigaku OD, 2019)'
_computing_data_reduction        'CrysAlisPro 1.171.40.67a (Rigaku OD, 2019)'
_computing_molecular_graphics    'Olex2 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'ShelXL (Sheldrick, 2015)'
_computing_structure_solution    'ShelXT (Sheldrick, 2015)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      200(140)
_diffrn_detector                 'Hybrid Pixel Array Detector'
_diffrn_detector_area_resol_mean 10.0000
_diffrn_detector_type            HyPix
_diffrn_measured_fraction_theta_full 0.918
_diffrn_measured_fraction_theta_max 0.844
_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     -7.00  28.00   0.50    0.60    --  -47.95  19.00  60.00   70
  2  \w    -23.00  27.00   0.50    0.60    --  -47.95  19.00 -30.00  100
  3  \w    -24.00  27.00   0.50    0.60    --  -47.95  19.00-150.00  102
  4  \w     30.00  55.00   0.50    0.60    --   47.95-123.00-145.00   50
  5  \w     36.00  73.00   0.50    2.40    --  104.75 -61.00-120.00   74
  6  \w     54.00 105.00   0.50    2.40    --  104.75 -94.00-150.00  102
  7  \w     32.00  68.00   0.50    2.40    --  104.75 -61.00-150.00   72
  8  \w    120.00 175.00   0.50    2.40    --  104.75  61.00   0.00  110
  9  \w    131.00 177.00   0.50    2.40    --  104.75  45.00  30.00   92
 10  \w     96.00 123.00   0.50    2.40    --  104.75  45.00  30.00   54
 11  \w     59.00 107.00   0.50    0.60    --   47.95-149.00  51.00   96
 12  \w     58.00  83.00   0.50    2.40    --  104.75-149.00  51.00   50
 13  \w    -93.00 -60.00   0.50    0.60    --  -47.95-149.00  51.00   66
 14  \w   -120.00 -77.00   0.50    0.60    --  -47.95-125.00 -30.00   86
 15  \w   -120.00 -73.00   0.50    0.60    --  -47.95-123.00-145.00   94
 16  \w   -162.00 -88.00   0.50    2.40    -- -102.00-123.00-145.00  148
 17  \w    -67.00 -42.00   0.50    2.40    -- -102.00  61.00  90.00   50
 18  \w    -65.00 -37.00   0.50    2.40    -- -102.00  61.00  60.00   56
 19  \w    -54.00 -29.00   0.50    2.40    -- -102.00  61.00 150.00   50
 20  \w    -90.00 -65.00   0.50    0.60    --  -47.95 149.00  98.00   50
 21  \w    -99.00 -49.00   0.50    2.40    -- -102.00  77.00 -60.00  100
 22  \w   -114.00 -79.00   0.50    2.40    -- -102.00 123.00 -65.00   70
 23  \w   -115.00 -29.00   0.50    2.40    -- -102.00 125.00 -30.00  172
 24  \w   -133.00 -31.00   0.50    2.40    -- -102.00 149.00  98.00  204
 25  \w   -120.00 -91.00   0.50    2.40    -- -102.00 -45.00 120.00   58
 26  \w   -169.00-144.00   0.50    2.40    -- -102.00 -45.00 120.00   50
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'XtaLAB Synergy R, DW system, HyPix'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      -0.0831330000
_diffrn_orient_matrix_UB_12      0.0488629000
_diffrn_orient_matrix_UB_13      -0.0086078000
_diffrn_orient_matrix_UB_21      0.0207160000
_diffrn_orient_matrix_UB_22      0.1864000000
_diffrn_orient_matrix_UB_23      0.0077181000
_diffrn_orient_matrix_UB_31      0.0099019000
_diffrn_orient_matrix_UB_32      0.0172790000
_diffrn_orient_matrix_UB_33      -0.0614646000
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.2119
_diffrn_reflns_av_unetI/netI     0.1169
_diffrn_reflns_Laue_measured_fraction_full 0.918
_diffrn_reflns_Laue_measured_fraction_max 0.844
_diffrn_reflns_limit_h_max       22
_diffrn_reflns_limit_h_min       -22
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            16928
_diffrn_reflns_point_group_measured_fraction_full 0.918
_diffrn_reflns_point_group_measured_fraction_max 0.844
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         77.673
_diffrn_reflns_theta_min         3.593
_diffrn_source                   'Rotating-anode X-ray tube'
_diffrn_source_type              'Rigaku (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    0.743
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.42487
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.40.67a (Rigaku Oxford Diffraction, 2019)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.245
_exptl_crystal_description       plate
_exptl_crystal_F_000             1412
_exptl_crystal_size_max          0.2
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.904
_refine_diff_density_min         -0.782
_refine_diff_density_rms         0.175
_refine_ls_extinction_coef       0.0043(15)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2014/7 (Sheldrick 2014'
_refine_ls_goodness_of_fit_ref   2.084
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     430
_refine_ls_number_reflns         6310
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      2.084
_refine_ls_R_factor_all          0.2419
_refine_ls_R_factor_gt           0.1929
_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^)+(0.2000P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.5026
_refine_ls_wR_factor_ref         0.5656
_reflns_Friedel_coverage         0.000
_reflns_number_gt                3742
_reflns_number_total             6310
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d1ob00526j2.cif
_cod_data_source_block           ljy_tm2_2133
_cod_depositor_comments          'Adding full bibliography for 7158026.cif.'
_cod_original_cell_volume        3507.9(14)
_cod_database_code               7158026
_shelx_shelxl_version_number     2014/7
_chemical_oxdiff_formula         'C H O N'
_shelx_estimated_absorpt_t_max   0.964
_shelx_estimated_absorpt_t_min   0.866
_diffrn_oxdiff_digest_frames
;
014a169fe894bb5444a24eb467dd69c93d000392ced
;
_diffrn_oxdiff_digest_hkl
;
010d00c8d4b5030833dc709ea810105a1ebf06
;
_reflns_odcompleteness_completeness 91.66
_reflns_odcompleteness_iscentric 1
_reflns_odcompleteness_theta     66.97
_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.a Ternary CH refined with riding coordinates:
 C30(H30)
2.b Secondary CH2 refined with riding coordinates:
 C2(H2A,H2B), C3(H3A,H3B), C4(H4A,H4B), C6(H6A,H6B), C7(H7A,H7B), C17(H17A,
 H17B), C18(H18A,H18B), C19(H19A,H19B), C20(H20A,H20B), C28(H28A,H28B),
 C29(H29A,H29B)
2.c Aromatic/amide H refined with riding coordinates:
 C5(H5), C10(H10), C12(H12), C13(H13), C24(H24), C25(H25), C27(H27), N1(H1),
 N2(H2), N3(H3), N4(H4)
2.d Idealised Me refined as rotating group:
 C1(H1A,H1B,H1C), C15(H15A,H15B,H15C), C31(H31A,H31B,H31C), C32(H32A,H32B,
 H32C), C34(H34A,H34B,H34C)
;
_shelx_res_checksum              29906
_shelx_hkl_checksum              88068
_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 2.740
_oxdiff_exptl_absorpt_empirical_full_min 0.371