Single-Conformation Spectroscopy of Capped Aminoisobutyric Acid Dipeptides: The Effect of C-Terminal Cap Chromophores on Conformation.
Fischer, Joshua L.; Elvir, Brayan R.; DeLucia, Sally-Ann; Blodgett, Karl N.; Zeller, Matthias; Kubasik, Matthew A.; Zwier, Timothy S.; The journal of physical chemistry. A 123 (2019) 4178–4187; doi:10.1021/acs.jpca.9b01698

data_1551027
_publ_section_title
;
 Single-Conformation Spectroscopy of Capped Aminoisobutyric Acid
 Dipeptides: The Effect of C-Terminal Cap Chromophores on Conformation.
;
_journal_issue                   19
_journal_name_full               'The journal of physical chemistry. A'
_journal_page_first              4178
_journal_page_last               4187
_journal_paper_doi               10.1021/acs.jpca.9b01698
_journal_volume                  123
_journal_year                    2019
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C18 H26 F N3 O3, 0.94(H2 O)'
_chemical_formula_sum            'C18 H27.88 F N3 O3.94'
_chemical_formula_weight         368.38
_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_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2018/3
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   8.5837(3)
_cell_length_b                   12.3394(4)
_cell_length_c                   19.5795(6)
_cell_measurement_reflns_used    9958
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      79.8651
_cell_measurement_theta_min      4.2360
_cell_volume                     2073.82(12)
_computing_cell_refinement       'SAINT V8.38A (Bruker, 2016)'
_computing_data_collection       'Apex3 v2017.3-0 (Bruker, 2017)'
_computing_data_reduction        'SAINT V8.38A (Bruker, 2016)'
_computing_structure_refinement
;  
SHELXL-2018/3 (Sheldrick, 2015, 2018), 
SHELXLE Rev937 (H\"ubschle et al., 2011)
;
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.989
_diffrn_measured_fraction_theta_max 0.978
_diffrn_measurement_device_type  'Bruker AXS D8 Quest CMOS diffractometer'
_diffrn_measurement_method       'omega and phi scans'
_diffrn_radiation_monochromator  'laterally graded multilayer (Goebel) mirror'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0293
_diffrn_reflns_av_unetI/netI     0.0246
_diffrn_reflns_Laue_measured_fraction_full 0.989
_diffrn_reflns_Laue_measured_fraction_max 0.978
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            15856
_diffrn_reflns_point_group_measured_fraction_full 0.989
_diffrn_reflns_point_group_measured_fraction_max 0.966
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         80.815
_diffrn_reflns_theta_min         4.235
_diffrn_source                   'I-mu-S microsource X-ray tube'
_exptl_absorpt_coefficient_mu    0.743
_exptl_absorpt_correction_T_max  0.7543
_exptl_absorpt_correction_T_min  0.6505
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
 SADABS 2016/2: Krause, L., Herbst-Irmer, R., Sheldrick G.M. & Stalke D.,
 J. Appl. Cryst. 48 (2015) 3-10
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.180
_exptl_crystal_description       block
_exptl_crystal_F_000             789.6
_exptl_crystal_size_max          0.230
_exptl_crystal_size_mid          0.220
_exptl_crystal_size_min          0.140
_refine_diff_density_max         0.144
_refine_diff_density_min         -0.158
_refine_diff_density_rms         0.025
_refine_ls_abs_structure_details
;
 Flack x determined using 1688 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.08(6)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.070
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     257
_refine_ls_number_reflns         4402
_refine_ls_number_restraints     5
_refine_ls_restrained_S_all      1.069
_refine_ls_R_factor_all          0.0373
_refine_ls_R_factor_gt           0.0350
_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^)+(0.0499P)^2^+0.2091P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0958
_refine_ls_wR_factor_ref         0.0981
_reflns_Friedel_coverage         0.734
_reflns_Friedel_fraction_full    0.989
_reflns_Friedel_fraction_max     0.951
_reflns_number_gt                4131
_reflns_number_total             4402
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jp9b01698_si_002.cif
_cod_data_source_block           Ac_Aib2_AMBA_F_0m
_cod_depositor_comments          'Adding full bibliography for 1551027.cif.'
_cod_database_code               1551027
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_min   0.848
_shelx_estimated_absorpt_t_max   0.903
_shelx_res_checksum              86439
_shelx_hkl_checksum              22791