The observation of a large gauche preference when 2-fluoroethylamine and 2-fluoroethanol become protonated.
Briggs, Caroline R. S.; Allen, Mark J.; O'Hagan, David; Tozer, David J.; Slawin, Alexandra M. Z.; Goeta, Andrés E; Howard, Judith A. K.; Organic & biomolecular chemistry 2 (2004) 732–740; doi:10.1039/b312188g

data_7151592
_publ_section_title
;
 The observation of a large gauche preference when 2-fluoroethylamine
 and 2-fluoroethanol become protonated.
;
_journal_issue                   5
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              732
_journal_page_last               740
_journal_paper_doi               10.1039/b312188g
_journal_volume                  2
_journal_year                    2004
_chemical_formula_moiety         'C4 H10  F2 N. Cl'
_chemical_formula_sum            'C4 H10 Cl F2 N'
_chemical_formula_weight         145.58
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 93.567(5)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   7.335(2)
_cell_length_b                   6.9524(19)
_cell_length_c                   13.170(4)
_cell_measurement_reflns_used    50
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      28
_cell_measurement_theta_min      12
_cell_volume                     670.3(3)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_detector_area_resol_mean 0.9
_diffrn_measured_fraction_theta_full 0.928
_diffrn_measured_fraction_theta_max 0.928
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0605
_diffrn_reflns_av_sigmaI/netI    0.0641
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -5
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            3017
_diffrn_reflns_theta_full        23.41
_diffrn_reflns_theta_max         23.41
_diffrn_reflns_theta_min         3.10
_exptl_absorpt_coefficient_mu    0.509
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.636707
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.443
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             304
_exptl_crystal_size_max          .12
_exptl_crystal_size_mid          .1
_exptl_crystal_size_min          .01
_refine_diff_density_max         0.892
_refine_diff_density_min         -0.330
_refine_diff_density_rms         0.084
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.925
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     81
_refine_ls_number_reflns         914
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      0.924
_refine_ls_R_factor_all          0.1038
_refine_ls_R_factor_gt           0.0645
_refine_ls_shift/su_max          0.010
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1273P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1541
_refine_ls_wR_factor_ref         0.1776
_reflns_number_gt                594
_reflns_number_total             914
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b312188g.txt
_cod_data_source_block           11
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to '/home/adriana/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from
2010-06-29.

'_exptl_absorpt_correction_type' value 'multiscan' changed to
'multi-scan' according to
'/home/adriana/struct/CIF-dictionaries/cif_core.dic' dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1555 2011-01-17 13:19:09Z saulius 
;
_cod_original_sg_symbol_H-M      P2(1)/n
_cod_database_code               7151592