Understanding ring-closing and racemization to prepare α-amino acid NCA and NTA monomers: a DFT study.
Bai, Tianwen; Shen, Bo; Cai, Da; Luo, Yifan; Zhou, Peng; Xia, Jingya; Zheng, Botuo; Zhang, Ke; Xie, Rongze; Ni, Xufeng; Xu, Maosheng; Ling, Jun; Sun, Jihong; Physical chemistry chemical physics : PCCP 22 (2020) 14868–14874; doi:10.1039/d0cp01174f

data_7240678
_publ_section_title
;
 Understanding ring-closing and racemization to prepare \a-amino acid NCA
 and NTA monomers: a DFT study.
;
_journal_issue                   26
_journal_name_full               'Physical chemistry chemical physics : PCCP'
_journal_page_first              14868
_journal_page_last               14874
_journal_paper_doi               10.1039/d0cp01174f
_journal_volume                  22
_journal_year                    2020
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C10 H9 N O2 S'
_chemical_formula_sum            'C10 H9 N O2 S'
_chemical_formula_weight         207.24
_chemical_name_systematic        DL-Phe-NTA
_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'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2018-12-11
_audit_creation_method
;
Olex2 1.2
(compiled 2018.05.29 svn.r3508 for OlexSys, GUI svn.r5506)
;
_audit_update_record
;
2020-01-21 deposited with the CCDC.	2020-06-09 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   5.2044(2)
_cell_length_b                   14.8960(7)
_cell_length_c                   25.4784(10)
_cell_measurement_reflns_used    6425
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      26.33
_cell_measurement_theta_min      2.73
_cell_volume                     1975.21(14)
_computing_cell_refinement       'SAINT V8.38A (?, 2016)'
_computing_data_reduction        'SAINT V8.38A (?, 2016)'
_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_temperature      293.15
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0373
_diffrn_reflns_av_unetI/netI     0.0329
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -18
_diffrn_reflns_limit_l_max       32
_diffrn_reflns_limit_l_min       -31
_diffrn_reflns_number            14300
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         26.751
_diffrn_reflns_theta_min         2.735
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.299
_exptl_absorpt_correction_T_max  0.7454
_exptl_absorpt_correction_T_min  0.6531
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1085 before and 0.0494 after correction.
The Ratio of minimum to maximum transmission is 0.8762.
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       needle
_exptl_crystal_F_000             864
_exptl_crystal_size_max          0.62
_exptl_crystal_size_mid          0.142
_exptl_crystal_size_min          0.078
_refine_diff_density_max         0.167
_refine_diff_density_min         -0.129
_refine_diff_density_rms         0.031
_refine_ls_abs_structure_details
;
 Flack x determined using 1364 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.05(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.030
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     253
_refine_ls_number_reflns         4192
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.030
_refine_ls_R_factor_all          0.0375
_refine_ls_R_factor_gt           0.0315
_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^)+(0.0346P)^2^+0.1673P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0721
_refine_ls_wR_factor_ref         0.0750
_reflns_Friedel_coverage         0.708
_reflns_Friedel_fraction_full    0.997
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                3737
_reflns_number_total             4192
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d0cp01174f2.cif
_cod_data_source_block           181211_phenta_0m
_cod_depositor_comments          'Adding full bibliography for 7240678.cif.'
_cod_database_code               7240678
_shelx_shelxl_version_number     2016/6
_shelx_estimated_absorpt_t_max   0.977
_shelx_estimated_absorpt_t_min   0.837
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups, All N(H) groups
2.a Ternary CH refined with riding coordinates:
 C8(H8), C18(H18)
2.b Secondary CH2 refined with riding coordinates:
 C7(H7A,H7B), C17(H17A,H17B)
2.c Aromatic/amide H refined with riding coordinates:
 N1(H1), C1(H1A), C2(H2), C3(H3), C4(H4), C5(H5), N2(H2A), C11(H11), C12(H12),
 C13(H13), C14(H14), C15(H15)
;
_shelx_res_checksum              94343
_olex2_submission_special_instructions 'No special instructions were received'