#------------------------------------------------------------------------------
#$Date: 2016-03-26 17:19:08 +0200 (Sat, 26 Mar 2016) $
#$Revision: 180387 $
#$URL: svn://www.crystallography.net/cod/cif/7/20/56/7205600.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_7205600
loop_
_publ_author_name
'Dobrzańska, Liliana'
_publ_section_title
;
 Anion directed supramolecular architectures of silver(i) complexes
 with 1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene and a
 reversible, solvent-induced structural change during a
 single-crystal-to-single-crystal transformation
;
_journal_issue                   7
_journal_name_full               CrystEngComm
_journal_page_first              2303
_journal_paper_doi               10.1039/c0ce00469c
_journal_volume                  13
_journal_year                    2011
_chemical_formula_sum            'C38 H46 Ag2 F12 N10 Sb2'
_chemical_formula_weight         1330.09
_chemical_name_common            work
_chemical_name_systematic
;
?
;
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                99.5060(10)
_cell_angle_beta                 101.9620(10)
_cell_angle_gamma                101.4790(10)
_cell_formula_units_Z            1
_cell_length_a                   8.6798(7)
_cell_length_b                   9.9988(8)
_cell_length_c                   13.7746(10)
_cell_measurement_reflns_used    9393
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      28.21
_cell_measurement_theta_min      2.347
_cell_volume                     1119.24(15)
_computing_cell_refinement       'SAINT (Bruker, 2002)'
_computing_data_collection       'SMART (Bruker, 2001)'
_computing_data_reduction        SAINT
_computing_molecular_graphics    'Mercury (Macrae, 2008)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.928
_diffrn_measurement_device_type  'Bruker APEX CCD area-detector'
_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  0.0192
_diffrn_reflns_av_sigmaI/netI    0.0228
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            13004
_diffrn_reflns_theta_full        26.50
_diffrn_reflns_theta_max         28.27
_diffrn_reflns_theta_min         1.55
_exptl_absorpt_coefficient_mu    2.148
_exptl_absorpt_correction_T_max  0.7826
_exptl_absorpt_correction_T_min  0.3956
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 1997)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.973
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             648
_exptl_crystal_size_max          0.43
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.12
_refine_diff_density_max         1.277
_refine_diff_density_min         -0.435
_refine_diff_density_rms         0.098
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.165
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     296
_refine_ls_number_reflns         5162
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.165
_refine_ls_R_factor_all          0.0280
_refine_ls_R_factor_gt           0.0270
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[σ²(Fo²)+(0.0252P)²+1.6652P] where P=(Fo²+2Fc²)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0640
_refine_ls_wR_factor_ref         0.0645
_reflns_number_gt                5041
_reflns_number_total             5162
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c0ce00469c.txt
_cod_data_source_block           1
_cod_original_sg_symbol_H-M      P-1
_cod_database_code               7205600
loop_
_symmetry_equiv_pos_as_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_symmetry_multiplicity
_atom_site_calc_flag
_atom_site_refinement_flags
_atom_site_disorder_assembly
_atom_site_disorder_group
Ag1 Ag 0.50528(2) 0.95374(2) 0.710762(15) 0.01783(6) Uani 1 1 d . . .
N1 N 0.7006(3) 0.8573(2) 0.73394(17) 0.0181(4) Uani 1 1 d . . .
C2 C 0.7375(3) 0.7838(3) 0.8031(2) 0.0162(5) Uani 1 1 d . . .
H2 H 0.6706 0.7563 0.8464 0.019 Uiso 1 1 calc R . .
N3 N 0.8817(3) 0.7529(2) 0.80428(16) 0.0152(4) Uani 1 1 d . . .
C4 C 0.9411(3) 0.8100(3) 0.7311(2) 0.0189(5) Uani 1 1 d . . .
H4 H 1.0407 0.8055 0.7140 0.023 Uiso 1 1 calc R . .
C5 C 0.8286(3) 0.8739(3) 0.6883(2) 0.0187(5) Uani 1 1 d . . .
H5 H 0.8367 0.9226 0.6352 0.022 Uiso 1 1 calc R . .
C6 C 0.9618(3) 0.6672(3) 0.8665(2) 0.0178(5) Uani 1 1 d . . .
H6A H 1.0755 0.7191 0.8989 0.021 Uiso 1 1 calc R . .
H6B H 0.9643 0.5802 0.8211 0.021 Uiso 1 1 calc R . .
C7 C 0.8800(3) 0.6287(3) 0.94853(19) 0.0148(5) Uani 1 1 d . . .
C8 C 0.7585(3) 0.5046(3) 0.92677(19) 0.0159(5) Uani 1 1 d . . .
C9 C 0.6949(3) 0.4637(3) 1.0049(2) 0.0169(5) Uani 1 1 d . . .
H9 H 0.6083 0.3825 0.9895 0.020 Uiso 1 1 calc R . .
C10 C 0.7544(3) 0.5383(3) 1.10489(19) 0.0154(5) Uani 1 1 d . . .
C11 C 0.8761(3) 0.6617(3) 1.12655(19) 0.0141(5) Uani 1 1 d . . .
C12 C 0.9336(3) 0.7109(3) 1.04776(19) 0.0147(5) Uani 1 1 d . . .
C13 C 1.0519(3) 0.8519(3) 1.0699(2) 0.0211(5) Uani 1 1 d . . .
H13A H 1.0488 0.8857 1.0069 0.032 Uiso 1 1 calc R . .
H13C H 1.1618 0.8430 1.0982 0.032 Uiso 1 1 calc R . .
H13B H 1.0218 0.9183 1.1190 0.032 Uiso 1 1 calc R . .
C14 C 0.6958(3) 0.4130(3) 0.8211(2) 0.0211(5) Uani 1 1 d . . .
H14C H 0.6009 0.3398 0.8194 0.032 Uiso 1 1 calc R . .
H14B H 0.7809 0.3698 0.8032 0.032 Uiso 1 1 calc R . .
H14A H 0.6648 0.4699 0.7723 0.032 Uiso 1 1 calc R . .
C15 C 0.6882(4) 0.4828(3) 1.1878(2) 0.0215(5) Uani 1 1 d . . .
H15A H 0.7689 0.4443 1.2277 0.032 Uiso 1 1 calc R . .
H15C H 0.5885 0.4093 1.1570 0.032 Uiso 1 1 calc R . .
H15B H 0.6642 0.5590 1.2322 0.032 Uiso 1 1 calc R . .
C16 C 0.9560(3) 0.7353(3) 1.23611(19) 0.0167(5) Uani 1 1 d . . .
H16A H 0.9787 0.6643 1.2757 0.020 Uiso 1 1 calc R . .
H16B H 1.0615 0.7977 1.2388 0.020 Uiso 1 1 calc R . .
N17 N 0.8597(3) 0.8186(2) 1.28533(16) 0.0143(4) Uani 1 1 d . . .
C18 C 0.7433(3) 0.8748(3) 1.2405(2) 0.0170(5) Uani 1 1 d . . .
H18 H 0.7039 0.8624 1.1691 0.020 Uiso 1 1 calc R . .
N19 N 0.6905(3) 0.9502(2) 1.30978(17) 0.0177(4) Uani 1 1 d . . .
C20 C 0.7796(3) 0.9410(3) 1.4029(2) 0.0204(5) Uani 1 1 d . . .
H20 H 0.7689 0.9845 1.4671 0.025 Uiso 1 1 calc R . .
C21 C 0.8845(3) 0.8605(3) 1.38870(19) 0.0187(5) Uani 1 1 d . . .
H21 H 0.9601 0.8375 1.4399 0.022 Uiso 1 1 calc R . .
Sb22 Sb 0.5000 1.0000 1.0000 0.01370(6) Uani 1 2 d S . .
F23 F 0.6823(2) 0.9258(2) 1.00470(14) 0.0312(4) Uani 1 1 d . . .
F24 F 0.6168(2) 1.14135(18) 1.11342(13) 0.0331(4) Uani 1 1 d . . .
F25 F 0.56552(19) 1.11448(16) 0.91332(12) 0.0206(3) Uani 1 1 d . . .
Sb26 Sb 1.0000 0.5000 0.5000 0.01769(7) Uani 1 2 d S . .
F27 F 1.1894(2) 0.4449(2) 0.55093(14) 0.0313(4) Uani 1 1 d . . .
F28 F 0.9413(2) 0.49606(18) 0.62373(12) 0.0267(4) Uani 1 1 d . . .
F29 F 0.8878(2) 0.31213(18) 0.45129(14) 0.0301(4) Uani 1 1 d . . .
N30 N 0.6612(3) 0.1341(3) 0.59478(19) 0.0265(5) Uani 1 1 d . . .
C31 C 0.6059(3) 0.2196(3) 0.5670(2) 0.0219(6) Uani 1 1 d . . .
C32 C 0.5347(4) 0.3297(3) 0.5328(3) 0.0307(7) Uani 1 1 d . . .
H32A H 0.6133 0.4202 0.5598 0.046 Uiso 1 1 calc R . .
H32B H 0.4367 0.3317 0.5573 0.046 Uiso 1 1 calc R . .
H32C H 0.5062 0.3110 0.4584 0.046 Uiso 1 1 calc R . .
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'
F F 0.0171 0.0103 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
Ag Ag -0.8971 1.1015 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
Sb Sb -0.5866 1.5461 '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
N1 Ag1 N19 178.96(9) . 2_677 ?
C2 N1 C5 105.7(2) . . ?
C2 N1 Ag1 127.64(19) . . ?
C5 N1 Ag1 126.21(18) . . ?
N1 C2 N3 111.4(2) . . ?
N1 C2 H2 124.3 . . ?
N3 C2 H2 124.3 . . ?
C2 N3 C4 107.2(2) . . ?
C2 N3 C6 128.1(2) . . ?
C4 N3 C6 124.6(2) . . ?
C5 C4 N3 106.2(2) . . ?
C5 C4 H4 126.9 . . ?
N3 C4 H4 126.9 . . ?
C4 C5 N1 109.5(2) . . ?
C4 C5 H5 125.2 . . ?
N1 C5 H5 125.2 . . ?
N3 C6 C7 114.1(2) . . ?
N3 C6 H6A 108.7 . . ?
C7 C6 H6A 108.7 . . ?
N3 C6 H6B 108.7 . . ?
C7 C6 H6B 108.7 . . ?
H6A C6 H6B 107.6 . . ?
C8 C7 C12 120.0(2) . . ?
C8 C7 C6 119.5(2) . . ?
C12 C7 C6 120.3(2) . . ?
C9 C8 C7 119.0(2) . . ?
C9 C8 C14 118.9(2) . . ?
C7 C8 C14 122.0(2) . . ?
C10 C9 C8 121.8(2) . . ?
C10 C9 H9 119.1 . . ?
C8 C9 H9 119.1 . . ?
C9 C10 C11 119.0(2) . . ?
C9 C10 C15 119.3(2) . . ?
C11 C10 C15 121.7(2) . . ?
C10 C11 C12 120.2(2) . . ?
C10 C11 C16 119.7(2) . . ?
C12 C11 C16 119.9(2) . . ?
C11 C12 C7 119.6(2) . . ?
C11 C12 C13 120.0(2) . . ?
C7 C12 C13 120.4(2) . . ?
C12 C13 H13A 109.5 . . ?
C12 C13 H13C 109.5 . . ?
H13A C13 H13C 109.5 . . ?
C12 C13 H13B 109.5 . . ?
H13A C13 H13B 109.5 . . ?
H13C C13 H13B 109.5 . . ?
C8 C14 H14C 109.5 . . ?
C8 C14 H14B 109.5 . . ?
H14C C14 H14B 109.5 . . ?
C8 C14 H14A 109.5 . . ?
H14C C14 H14A 109.5 . . ?
H14B C14 H14A 109.5 . . ?
C10 C15 H15A 109.5 . . ?
C10 C15 H15C 109.5 . . ?
H15A C15 H15C 109.5 . . ?
C10 C15 H15B 109.5 . . ?
H15A C15 H15B 109.5 . . ?
H15C C15 H15B 109.5 . . ?
N17 C16 C11 114.8(2) . . ?
N17 C16 H16A 108.6 . . ?
C11 C16 H16A 108.6 . . ?
N17 C16 H16B 108.6 . . ?
C11 C16 H16B 108.6 . . ?
H16A C16 H16B 107.5 . . ?
C18 N17 C21 107.8(2) . . ?
C18 N17 C16 127.7(2) . . ?
C21 N17 C16 124.3(2) . . ?
N19 C18 N17 110.6(2) . . ?
N19 C18 H18 124.7 . . ?
N17 C18 H18 124.7 . . ?
C18 N19 C20 105.8(2) . . ?
C18 N19 Ag1 129.15(18) . 2_677 ?
C20 N19 Ag1 124.69(18) . 2_677 ?
C21 C20 N19 109.5(2) . . ?
C21 C20 H20 125.2 . . ?
N19 C20 H20 125.2 . . ?
C20 C21 N17 106.2(2) . . ?
C20 C21 H21 126.9 . . ?
N17 C21 H21 126.9 . . ?
F23 Sb22 F23 180.000(1) 2_677 . ?
F23 Sb22 F24 90.18(9) 2_677 . ?
F23 Sb22 F24 89.82(9) . . ?
F23 Sb22 F24 89.82(9) 2_677 2_677 ?
F23 Sb22 F24 90.18(9) . 2_677 ?
F24 Sb22 F24 180.000(1) . 2_677 ?
F23 Sb22 F25 88.73(7) 2_677 . ?
F23 Sb22 F25 91.27(7) . . ?
F24 Sb22 F25 90.19(8) . . ?
F24 Sb22 F25 89.81(7) 2_677 . ?
F23 Sb22 F25 91.27(7) 2_677 2_677 ?
F23 Sb22 F25 88.73(7) . 2_677 ?
F24 Sb22 F25 89.81(7) . 2_677 ?
F24 Sb22 F25 90.19(8) 2_677 2_677 ?
F25 Sb22 F25 180.000(1) . 2_677 ?
F27 Sb26 F27 180.000(1) . 2_766 ?
F27 Sb26 F29 89.94(9) . 2_766 ?
F27 Sb26 F29 90.06(9) 2_766 2_766 ?
F27 Sb26 F29 90.06(9) . . ?
F27 Sb26 F29 89.94(9) 2_766 . ?
F29 Sb26 F29 180.0 2_766 . ?
F27 Sb26 F28 90.16(8) . . ?
F27 Sb26 F28 89.84(8) 2_766 . ?
F29 Sb26 F28 90.43(8) 2_766 . ?
F29 Sb26 F28 89.57(8) . . ?
F27 Sb26 F28 89.84(8) . 2_766 ?
F27 Sb26 F28 90.16(8) 2_766 2_766 ?
F29 Sb26 F28 89.57(8) 2_766 2_766 ?
F29 Sb26 F28 90.43(8) . 2_766 ?
F28 Sb26 F28 180.0 . 2_766 ?
N30 C31 C32 179.2(3) . . ?
C31 C32 H32A 109.5 . . ?
C31 C32 H32B 109.5 . . ?
H32A C32 H32B 109.5 . . ?
C31 C32 H32C 109.5 . . ?
H32A C32 H32C 109.5 . . ?
H32B C32 H32C 109.5 . . ?
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
Ag1 N1 2.105(2) . ?
Ag1 N19 2.105(2) 2_677 ?
N1 C2 1.322(3) . ?
N1 C5 1.381(3) . ?
C2 N3 1.345(3) . ?
C2 H2 0.9500 . ?
N3 C4 1.377(3) . ?
N3 C6 1.478(3) . ?
C4 C5 1.358(4) . ?
C4 H4 0.9500 . ?
C5 H5 0.9500 . ?
C6 C7 1.516(3) . ?
C6 H6A 0.9900 . ?
C6 H6B 0.9900 . ?
C7 C8 1.402(4) . ?
C7 C12 1.405(4) . ?
C8 C9 1.390(4) . ?
C8 C14 1.512(4) . ?
C9 C10 1.390(4) . ?
C9 H9 0.9500 . ?
C10 C11 1.399(4) . ?
C10 C15 1.515(4) . ?
C11 C12 1.404(4) . ?
C11 C16 1.515(3) . ?
C12 C13 1.512(4) . ?
C13 H13A 0.9800 . ?
C13 H13C 0.9800 . ?
C13 H13B 0.9800 . ?
C14 H14C 0.9800 . ?
C14 H14B 0.9800 . ?
C14 H14A 0.9800 . ?
C15 H15A 0.9800 . ?
C15 H15C 0.9800 . ?
C15 H15B 0.9800 . ?
C16 N17 1.476(3) . ?
C16 H16A 0.9900 . ?
C16 H16B 0.9900 . ?
N17 C18 1.342(3) . ?
N17 C21 1.375(3) . ?
C18 N19 1.330(3) . ?
C18 H18 0.9500 . ?
N19 C20 1.381(3) . ?
N19 Ag1 2.105(2) 2_677 ?
C20 C21 1.352(4) . ?
C20 H20 0.9500 . ?
C21 H21 0.9500 . ?
Sb22 F23 1.8711(17) 2_677 ?
Sb22 F23 1.8711(17) . ?
Sb22 F24 1.8734(17) . ?
Sb22 F24 1.8734(17) 2_677 ?
Sb22 F25 1.8796(15) . ?
Sb22 F25 1.8796(15) 2_677 ?
Sb26 F27 1.8727(17) . ?
Sb26 F27 1.8727(17) 2_766 ?
Sb26 F29 1.8741(17) 2_766 ?
Sb26 F29 1.8741(17) . ?
Sb26 F28 1.8815(16) . ?
Sb26 F28 1.8815(16) 2_766 ?
N30 C31 1.141(4) . ?
C31 C32 1.462(4) . ?
C32 H32A 0.9800 . ?
C32 H32B 0.9800 . ?
C32 H32C 0.9800 . ?
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
C5 N1 C2 N3 0.1(3) . . . . ?
Ag1 N1 C2 N3 -172.12(17) . . . . ?
N1 C2 N3 C4 -0.1(3) . . . . ?
N1 C2 N3 C6 -176.7(2) . . . . ?
C2 N3 C4 C5 0.1(3) . . . . ?
C6 N3 C4 C5 176.8(2) . . . . ?
N3 C4 C5 N1 0.0(3) . . . . ?
C2 N1 C5 C4 -0.1(3) . . . . ?
Ag1 N1 C5 C4 172.30(18) . . . . ?
C2 N3 C6 C7 -9.6(4) . . . . ?
C4 N3 C6 C7 174.4(2) . . . . ?
N3 C6 C7 C8 90.4(3) . . . . ?
N3 C6 C7 C12 -94.4(3) . . . . ?
C12 C7 C8 C9 -1.1(4) . . . . ?
C6 C7 C8 C9 174.1(2) . . . . ?
C12 C7 C8 C14 179.5(2) . . . . ?
C6 C7 C8 C14 -5.2(4) . . . . ?
C7 C8 C9 C10 -3.5(4) . . . . ?
C14 C8 C9 C10 175.8(2) . . . . ?
C8 C9 C10 C11 3.3(4) . . . . ?
C8 C9 C10 C15 -175.7(2) . . . . ?
C9 C10 C11 C12 1.7(4) . . . . ?
C15 C10 C11 C12 -179.4(2) . . . . ?
C9 C10 C11 C16 -172.9(2) . . . . ?
C15 C10 C11 C16 6.0(4) . . . . ?
C10 C11 C12 C7 -6.3(4) . . . . ?
C16 C11 C12 C7 168.3(2) . . . . ?
C10 C11 C12 C13 173.4(2) . . . . ?
C16 C11 C12 C13 -11.9(3) . . . . ?
C8 C7 C12 C11 6.0(4) . . . . ?
C6 C7 C12 C11 -169.2(2) . . . . ?
C8 C7 C12 C13 -173.7(2) . . . . ?
C6 C7 C12 C13 11.1(3) . . . . ?
C10 C11 C16 N17 -78.4(3) . . . . ?
C12 C11 C16 N17 106.9(3) . . . . ?
C11 C16 N17 C18 -24.2(4) . . . . ?
C11 C16 N17 C21 160.8(2) . . . . ?
C21 N17 C18 N19 -0.5(3) . . . . ?
C16 N17 C18 N19 -176.1(2) . . . . ?
N17 C18 N19 C20 0.3(3) . . . . ?
N17 C18 N19 Ag1 -172.88(18) . . . 2_677 ?
C18 N19 C20 C21 0.0(3) . . . . ?
Ag1 N19 C20 C21 173.55(19) 2_677 . . . ?
N19 C20 C21 N17 -0.3(3) . . . . ?
C18 N17 C21 C20 0.4(3) . . . . ?
C16 N17 C21 C20 176.3(2) . . . . ?
