#------------------------------------------------------------------------------
#$Date: 2020-04-18 01:36:09 +0300 (Sat, 18 Apr 2020) $
#$Revision: 250907 $
#$URL: file:///home/coder/svn-repositories/cod/cif/7/24/03/7240329.cif $
#------------------------------------------------------------------------------
#
# This file is available in the Crystallography Open Database (COD),
# http://www.crystallography.net/
#
# All data on this site have been placed in the public domain by the
# contributors.
#
data_7240329
loop_
_publ_author_name
'Ahmed, Muhammad Naeem'
'Ansar, Khawaja Yasin'
'Aziz, Shahid'
'Khan, Saba'
'Tahir, Muhammad Nawaz'
'Gil, Diego M.'
'Frontera, Antonio'
_publ_section_title
;
 Relevant π--hole tetrel bonding interactions in ethyl
 2-triazolyl-2-oxo-acetate derivatives: Hirshfeld surface analysis and DFT
 calculations
;
_journal_name_full               CrystEngComm
_journal_paper_doi               10.1039/D0CE00335B
_journal_year                    2020
_chemical_formula_iupac          'C20 H19 N3 O4'
_chemical_formula_moiety         'C20 H19 N3 O4'
_chemical_formula_sum            'C20 H19 N3 O4'
_chemical_formula_weight         365.38
_chemical_name_systematic
;
Ethyl 2-(1-benzyl-4-(4-methoxyphenyl)-1H-1,2,3-triazol-5-yl)-2-oxoacetate
;
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2018/3
_audit_update_record
;
2019-12-30 deposited with the CCDC.	2020-04-17 downloaded from the CCDC.
;
_cell_angle_alpha                111.004(2)
_cell_angle_beta                 99.018(3)
_cell_angle_gamma                97.623(2)
_cell_formula_units_Z            2
_cell_length_a                   8.2922(6)
_cell_length_b                   9.4246(7)
_cell_length_c                   12.9343(10)
_cell_measurement_reflns_used    3299
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      27.230
_cell_measurement_theta_min      1.729
_cell_volume                     912.24(12)
_computing_cell_refinement       'SAINT (Bruker, 2007)'
_computing_data_collection       'APEX2 (Bruker, 2007)'
_computing_data_reduction        'SAINT (Bruker, 2007)'
_computing_molecular_graphics
'ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009)'
_computing_publication_material
;
WinGX (Farrugia, 1999) and PLATON (Spek, 2009)
;
_computing_structure_refinement  'SHELXL-2018/3  (Sheldrick, 2015)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      296(2)
_diffrn_detector_area_resol_mean 7.77
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.985
_diffrn_measurement_device_type  'Bruker Kappa APEXII CCD'
_diffrn_measurement_method       ω
_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  0.0271
_diffrn_reflns_av_unetI/netI     0.0205
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            14140
_diffrn_reflns_theta_full        27.230
_diffrn_reflns_theta_max         27.230
_diffrn_reflns_theta_min         1.729
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.094
_exptl_absorpt_correction_T_max  0.746
_exptl_absorpt_correction_T_min  0.670
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Bruker, 2005)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.330
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       rod
_exptl_crystal_F_000             384
_exptl_crystal_size_max          0.36
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.25
_refine_diff_density_max         0.258
_refine_diff_density_min         -0.250
_refine_diff_density_rms         0.035
_refine_ls_extinction_coef       0.131(7)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2018/3 (Sheldrick 2018)'
_refine_ls_goodness_of_fit_ref   1.045
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     249
_refine_ls_number_reflns         4016
_refine_ls_number_restraints     4
_refine_ls_restrained_S_all      1.050
_refine_ls_R_factor_all          0.0553
_refine_ls_R_factor_gt           0.0456
_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/[σ²(Fo²)+(0.0541P)²+0.2677P] where P=(Fo²+2Fc²)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1169
_refine_ls_wR_factor_ref         0.1259
_reflns_number_gt                3299
_reflns_number_total             4016
_reflns_threshold_expression     I>2σ(I)
_cod_data_source_file            d0ce00335b2.cif
_cod_data_source_block           ACHINA
_cod_database_code               7240329
_shelx_shelxl_version_number     2018/3
_shelx_space_group_comment
;
The symmetry employed for this shelxl refinement is uniquely defined
by the following loop, which should always be used as a source of
symmetry information in preference to the above space-group names.
They are only intended as comments.
;
_shelx_estimated_absorpt_t_min   0.930
_shelx_estimated_absorpt_t_max   0.970
loop_
_space_group_symop_operation_xyz
'x, y, z'
'-x, -y, -z'
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_adp_type
_atom_site_occupancy
_atom_site_site_symmetry_order
_atom_site_calc_flag
_atom_site_refinement_flags_posn
_atom_site_refinement_flags_adp
_atom_site_refinement_flags_occupancy
_atom_site_disorder_assembly
_atom_site_disorder_group
O1 O 0.89719(16) -0.02911(13) 0.21123(9) 0.0572(3) Uani 1 1 d D . . . .
O2 O 0.93912(18) -0.13576(14) 0.03570(11) 0.0678(4) Uani 1 1 d . . . . .
O3 O 0.69561(14) 0.03169(13) -0.00492(9) 0.0574(3) Uani 1 1 d . . . . .
O4 O 1.56414(17) 0.2433(2) 0.47612(11) 0.0788(4) Uani 1 1 d . . . . .
N1 N 0.92934(17) 0.47083(15) 0.30574(10) 0.0495(3) Uani 1 1 d . . . . .
N2 N 0.79076(18) 0.47683(15) 0.24387(11) 0.0524(3) Uani 1 1 d . . . . .
N3 N 0.73641(15) 0.34026(14) 0.15706(10) 0.0429(3) Uani 1 1 d . . . . .
C1A C 0.9745(11) -0.1138(5) 0.3581(3) 0.0942(12) Uani 0.719(11) 1 d D . P A 1
H1A H 1.037543 -0.012062 0.406964 0.141 Uiso 0.719(11) 1 calc R U P A 1
H1B H 1.019845 -0.190142 0.379808 0.141 Uiso 0.719(11) 1 calc R U P A 1
H1C H 0.860231 -0.120824 0.364531 0.141 Uiso 0.719(11) 1 calc R U P A 1
C2A C 0.9834(16) -0.1417(11) 0.2416(7) 0.0942(12) Uani 0.719(11) 1 d D . P A 1
H2A H 0.928580 -0.247290 0.191845 0.113 Uiso 0.719(11) 1 calc R U P A 1
H2B H 1.098705 -0.125423 0.234959 0.113 Uiso 0.719(11) 1 calc R U P A 1
C1B C 1.069(3) -0.0907(13) 0.3504(8) 0.0942(12) Uani 0.281(11) 1 d D . P A 2
H1D H 1.174590 -0.037573 0.348588 0.141 Uiso 0.281(11) 1 calc R U P A 2
H1E H 1.083915 -0.176166 0.372003 0.141 Uiso 0.281(11) 1 calc R U P A 2
H1F H 1.019789 -0.020088 0.404412 0.141 Uiso 0.281(11) 1 calc R U P A 2
C2B C 0.961(4) -0.147(3) 0.2406(17) 0.0942(12) Uani 0.281(11) 1 d D . P A 2
H2C H 0.867599 -0.223996 0.237294 0.113 Uiso 0.281(11) 1 calc R U P A 2
H2D H 1.021243 -0.199154 0.184519 0.113 Uiso 0.281(11) 1 calc R U P A 2
C3 C 0.89208(19) -0.04003(17) 0.10655(12) 0.0450(3) Uani 1 1 d . . . . .
C4 C 0.80242(17) 0.08012(16) 0.08155(12) 0.0405(3) Uani 1 1 d . . . . .
C5 C 0.84109(17) 0.24126(16) 0.16276(11) 0.0378(3) Uani 1 1 d . . . . .
C6 C 0.96564(18) 0.32810(16) 0.25877(11) 0.0398(3) Uani 1 1 d . . . . .
C7 C 1.11941(17) 0.29621(16) 0.31129(11) 0.0402(3) Uani 1 1 d . . . . .
C8 C 1.22540(19) 0.22204(18) 0.24779(12) 0.0465(4) Uani 1 1 d . . . . .
H8 H 1.195927 0.185458 0.169000 0.056 Uiso 1 1 calc R U . . .
C9 C 1.3745(2) 0.2014(2) 0.29960(13) 0.0536(4) Uani 1 1 d . . . . .
H9 H 1.444335 0.151063 0.255787 0.064 Uiso 1 1 calc R U . . .
C10 C 1.4193(2) 0.2558(2) 0.41651(13) 0.0536(4) Uani 1 1 d . . . . .
C11 C 1.3134(2) 0.3284(2) 0.48115(13) 0.0575(4) Uani 1 1 d . . . . .
H11 H 1.342303 0.363299 0.559870 0.069 Uiso 1 1 calc R U . . .
C12 C 1.1656(2) 0.34911(19) 0.42919(12) 0.0504(4) Uani 1 1 d . . . . .
H12 H 1.095673 0.398954 0.473209 0.060 Uiso 1 1 calc R U . . .
C13 C 1.6897(3) 0.1986(4) 0.4175(2) 0.0975(8) Uani 1 1 d . . . . .
H13A H 1.656724 0.090717 0.368263 0.146 Uiso 1 1 calc R U . . .
H13B H 1.791587 0.214929 0.470954 0.146 Uiso 1 1 calc R U . . .
H13C H 1.706790 0.259683 0.373071 0.146 Uiso 1 1 calc R U . . .
C14 C 0.58683(18) 0.3217(2) 0.07231(13) 0.0486(4) Uani 1 1 d . . . . .
H14A H 0.523266 0.398745 0.105946 0.058 Uiso 1 1 calc R U . . .
H14B H 0.517595 0.219932 0.051032 0.058 Uiso 1 1 calc R U . . .
C15 C 0.62686(17) 0.33886(17) -0.03277(12) 0.0436(3) Uani 1 1 d . . . . .
C16 C 0.5324(2) 0.2444(2) -0.13827(16) 0.0697(5) Uani 1 1 d . . . . .
H16 H 0.447147 0.164440 -0.145360 0.084 Uiso 1 1 calc R U . . .
C17 C 0.5620(3) 0.2662(3) -0.23451(17) 0.0804(6) Uani 1 1 d . . . . .
H17 H 0.495802 0.201661 -0.305332 0.096 Uiso 1 1 calc R U . . .
C18 C 0.6872(2) 0.3811(2) -0.22616(15) 0.0637(5) Uani 1 1 d . . . . .
H18 H 0.706871 0.395605 -0.290851 0.076 Uiso 1 1 calc R U . . .
C19 C 0.7830(2) 0.4743(2) -0.12259(16) 0.0630(5) Uani 1 1 d . . . . .
H19 H 0.869438 0.552622 -0.116371 0.076 Uiso 1 1 calc R U . . .
C20 C 0.7534(2) 0.4540(2) -0.02636(14) 0.0556(4) Uani 1 1 d . . . . .
H20 H 0.820186 0.519267 0.044087 0.067 Uiso 1 1 calc R U . . .
loop_
_atom_type_symbol
_atom_type_description
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
_atom_type_scat_source
C C 0.0033 0.0016 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
H H 0.0000 0.0000 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
N N 0.0061 0.0033 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
O O 0.0106 0.0060 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
loop_
_geom_angle_atom_site_label_1
_geom_angle_atom_site_label_2
_geom_angle_atom_site_label_3
_geom_angle
_geom_angle_site_symmetry_1
_geom_angle_site_symmetry_3
_geom_angle_publ_flag
C3 O1 C2B 116.2(10) . . ?
C3 O1 C2A 114.1(4) . . ?
C10 O4 C13 118.00(15) . . ?
N2 N1 C6 109.23(12) . . ?
N1 N2 N3 108.18(11) . . ?
N2 N3 C5 110.42(12) . . ?
N2 N3 C14 118.14(12) . . ?
C5 N3 C14 131.38(12) . . ?
C2A C1A H1A 109.5 . . ?
C2A C1A H1B 109.5 . . ?
H1A C1A H1B 109.5 . . ?
C2A C1A H1C 109.5 . . ?
H1A C1A H1C 109.5 . . ?
H1B C1A H1C 109.5 . . ?
C1A C2A O1 106.1(7) . . ?
C1A C2A H2A 110.5 . . ?
O1 C2A H2A 110.5 . . ?
C1A C2A H2B 110.5 . . ?
O1 C2A H2B 110.5 . . ?
H2A C2A H2B 108.7 . . ?
C2B C1B H1D 109.5 . . ?
C2B C1B H1E 109.5 . . ?
H1D C1B H1E 109.5 . . ?
C2B C1B H1F 109.5 . . ?
H1D C1B H1F 109.5 . . ?
H1E C1B H1F 109.5 . . ?
C1B C2B O1 114.1(16) . . ?
C1B C2B H2C 108.7 . . ?
O1 C2B H2C 108.7 . . ?
C1B C2B H2D 108.7 . . ?
O1 C2B H2D 108.7 . . ?
H2C C2B H2D 107.6 . . ?
O2 C3 O1 126.11(14) . . ?
O2 C3 C4 122.55(14) . . ?
O1 C3 C4 111.15(12) . . ?
O3 C4 C5 123.39(13) . . ?
O3 C4 C3 116.18(13) . . ?
C5 C4 C3 120.35(12) . . ?
N3 C5 C6 104.36(12) . . ?
N3 C5 C4 121.06(12) . . ?
C6 C5 C4 134.46(13) . . ?
N1 C6 C5 107.80(12) . . ?
N1 C6 C7 118.97(12) . . ?
C5 C6 C7 133.20(13) . . ?
C8 C7 C12 118.47(13) . . ?
C8 C7 C6 122.09(12) . . ?
C12 C7 C6 119.35(13) . . ?
C9 C8 C7 121.06(13) . . ?
C9 C8 H8 119.5 . . ?
C7 C8 H8 119.5 . . ?
C10 C9 C8 119.82(14) . . ?
C10 C9 H9 120.1 . . ?
C8 C9 H9 120.1 . . ?
O4 C10 C9 124.58(15) . . ?
O4 C10 C11 115.67(14) . . ?
C9 C10 C11 119.76(14) . . ?
C12 C11 C10 120.16(14) . . ?
C12 C11 H11 119.9 . . ?
C10 C11 H11 119.9 . . ?
C11 C12 C7 120.72(14) . . ?
C11 C12 H12 119.6 . . ?
C7 C12 H12 119.6 . . ?
O4 C13 H13A 109.5 . . ?
O4 C13 H13B 109.5 . . ?
H13A C13 H13B 109.5 . . ?
O4 C13 H13C 109.5 . . ?
H13A C13 H13C 109.5 . . ?
H13B C13 H13C 109.5 . . ?
N3 C14 C15 112.79(12) . . ?
N3 C14 H14A 109.0 . . ?
C15 C14 H14A 109.0 . . ?
N3 C14 H14B 109.0 . . ?
C15 C14 H14B 109.0 . . ?
H14A C14 H14B 107.8 . . ?
C16 C15 C20 117.58(15) . . ?
C16 C15 C14 120.80(15) . . ?
C20 C15 C14 121.55(14) . . ?
C15 C16 C17 120.99(17) . . ?
C15 C16 H16 119.5 . . ?
C17 C16 H16 119.5 . . ?
C18 C17 C16 120.44(18) . . ?
C18 C17 H17 119.8 . . ?
C16 C17 H17 119.8 . . ?
C19 C18 C17 119.29(17) . . ?
C19 C18 H18 120.4 . . ?
C17 C18 H18 120.4 . . ?
C18 C19 C20 120.59(17) . . ?
C18 C19 H19 119.7 . . ?
C20 C19 H19 119.7 . . ?
C15 C20 C19 121.11(16) . . ?
C15 C20 H20 119.4 . . ?
C19 C20 H20 119.4 . . ?
loop_
_geom_bond_atom_site_label_1
_geom_bond_atom_site_label_2
_geom_bond_distance
_geom_bond_site_symmetry_2
_geom_bond_publ_flag
O1 C3 1.3139(18) . ?
O1 C2B 1.436(17) . ?
O1 C2A 1.484(7) . ?
O2 C3 1.1910(18) . ?
O3 C4 1.2083(17) . ?
O4 C10 1.3648(19) . ?
O4 C13 1.405(3) . ?
N1 N2 1.3136(18) . ?
N1 C6 1.3595(19) . ?
N2 N3 1.3312(18) . ?
N3 C5 1.3688(17) . ?
N3 C14 1.4662(18) . ?
C1A C2A 1.449(11) . ?
C1A H1A 0.9600 . ?
C1A H1B 0.9600 . ?
C1A H1C 0.9600 . ?
C2A H2A 0.9700 . ?
C2A H2B 0.9700 . ?
C1B C2B 1.425(18) . ?
C1B H1D 0.9600 . ?
C1B H1E 0.9600 . ?
C1B H1F 0.9600 . ?
C2B H2C 0.9700 . ?
C2B H2D 0.9700 . ?
C3 C4 1.533(2) . ?
C4 C5 1.461(2) . ?
C5 C6 1.3869(19) . ?
C6 C7 1.4677(19) . ?
C7 C8 1.383(2) . ?
C7 C12 1.3935(19) . ?
C8 C9 1.383(2) . ?
C8 H8 0.9300 . ?
C9 C10 1.380(2) . ?
C9 H9 0.9300 . ?
C10 C11 1.385(2) . ?
C11 C12 1.375(2) . ?
C11 H11 0.9300 . ?
C12 H12 0.9300 . ?
C13 H13A 0.9600 . ?
C13 H13B 0.9600 . ?
C13 H13C 0.9600 . ?
C14 C15 1.506(2) . ?
C14 H14A 0.9700 . ?
C14 H14B 0.9700 . ?
C15 C16 1.370(2) . ?
C15 C20 1.376(2) . ?
C16 C17 1.385(3) . ?
C16 H16 0.9300 . ?
C17 C18 1.358(3) . ?
C17 H17 0.9300 . ?
C18 C19 1.355(3) . ?
C18 H18 0.9300 . ?
C19 C20 1.378(2) . ?
C19 H19 0.9300 . ?
C20 H20 0.9300 . ?
loop_
_geom_hbond_atom_site_label_D
_geom_hbond_atom_site_label_H
_geom_hbond_atom_site_label_A
_geom_hbond_distance_DH
_geom_hbond_distance_HA
_geom_hbond_distance_DA
_geom_hbond_angle_DHA
_geom_hbond_site_symmetry_A
_geom_hbond_publ_flag
C14 H14B O3 0.97 2.58 3.542(2) 172.5 2_655 yes
loop_
_geom_torsion_atom_site_label_1
_geom_torsion_atom_site_label_2
_geom_torsion_atom_site_label_3
_geom_torsion_atom_site_label_4
_geom_torsion
_geom_torsion_site_symmetry_1
_geom_torsion_site_symmetry_2
_geom_torsion_site_symmetry_3
_geom_torsion_site_symmetry_4
_geom_torsion_publ_flag
C6 N1 N2 N3 -0.18(17) . . . . ?
N1 N2 N3 C5 0.71(16) . . . . ?
N1 N2 N3 C14 -176.85(12) . . . . ?
C3 O1 C2A C1A -179.2(7) . . . . ?
C3 O1 C2B C1B 138.7(19) . . . . ?
C2B O1 C3 O2 -2.1(14) . . . . ?
C2A O1 C3 O2 5.3(6) . . . . ?
C2B O1 C3 C4 173.0(14) . . . . ?
C2A O1 C3 C4 -179.6(5) . . . . ?
O2 C3 C4 O3 44.2(2) . . . . ?
O1 C3 C4 O3 -131.09(14) . . . . ?
O2 C3 C4 C5 -138.95(16) . . . . ?
O1 C3 C4 C5 45.74(18) . . . . ?
N2 N3 C5 C6 -0.93(15) . . . . ?
C14 N3 C5 C6 176.21(14) . . . . ?
N2 N3 C5 C4 175.62(12) . . . . ?
C14 N3 C5 C4 -7.2(2) . . . . ?
O3 C4 C5 N3 13.2(2) . . . . ?
C3 C4 C5 N3 -163.42(12) . . . . ?
O3 C4 C5 C6 -171.52(15) . . . . ?
C3 C4 C5 C6 11.9(2) . . . . ?
N2 N1 C6 C5 -0.40(16) . . . . ?
N2 N1 C6 C7 177.72(12) . . . . ?
N3 C5 C6 N1 0.79(15) . . . . ?
C4 C5 C6 N1 -175.06(14) . . . . ?
N3 C5 C6 C7 -176.95(14) . . . . ?
C4 C5 C6 C7 7.2(3) . . . . ?
N1 C6 C7 C8 -134.62(15) . . . . ?
C5 C6 C7 C8 42.9(2) . . . . ?
N1 C6 C7 C12 41.9(2) . . . . ?
C5 C6 C7 C12 -140.54(16) . . . . ?
C12 C7 C8 C9 -0.4(2) . . . . ?
C6 C7 C8 C9 176.13(15) . . . . ?
C7 C8 C9 C10 -0.2(3) . . . . ?
C13 O4 C10 C9 12.3(3) . . . . ?
C13 O4 C10 C11 -167.9(2) . . . . ?
C8 C9 C10 O4 -179.16(17) . . . . ?
C8 C9 C10 C11 1.0(3) . . . . ?
O4 C10 C11 C12 178.90(17) . . . . ?
C9 C10 C11 C12 -1.3(3) . . . . ?
C10 C11 C12 C7 0.7(3) . . . . ?
C8 C7 C12 C11 0.2(2) . . . . ?
C6 C7 C12 C11 -176.47(15) . . . . ?
N2 N3 C14 C15 99.51(16) . . . . ?
C5 N3 C14 C15 -77.45(19) . . . . ?
N3 C14 C15 C16 140.33(17) . . . . ?
N3 C14 C15 C20 -42.9(2) . . . . ?
C20 C15 C16 C17 -1.1(3) . . . . ?
C14 C15 C16 C17 175.80(19) . . . . ?
C15 C16 C17 C18 0.8(4) . . . . ?
C16 C17 C18 C19 0.0(3) . . . . ?
C17 C18 C19 C20 -0.5(3) . . . . ?
C16 C15 C20 C19 0.6(3) . . . . ?
C14 C15 C20 C19 -176.26(15) . . . . ?
C18 C19 C20 C15 0.2(3) . . . . ?
