Concurrent anion...pi interactions between a perchlorate ion and two pi-acidic aromatic rings, namely pentafluorophenol and 1,3,5-triazine.
Götz, Rens J; Robertazzi, Arturo; Mutikainen, Ilpo; Turpeinen, Urho; Gamez, Patrick; Reedijk, Jan; Chemical communications (Cambridge, England)  (2008) 3384–3386; doi:10.1039/b803817a

data_7103250
_publ_section_title
;
 Concurrent anion...pi interactions between a perchlorate ion and two
 pi-acidic aromatic rings, namely pentafluorophenol and 1,3,5-triazine.
;
_journal_issue                   29
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              3384
_journal_page_last               3386
_journal_paper_doi               10.1039/b803817a
_journal_year                    2008
_chemical_formula_moiety         'C25 H13 F5 N6 O2'
_chemical_formula_sum            'C50 H26 F10 N12 O4'
_chemical_formula_weight         1048.83
_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                 98.20(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   16.139(3)
_cell_length_b                   6.2526(13)
_cell_length_c                   44.715(8)
_cell_measurement_reflns_used    45860
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      25.10
_cell_measurement_theta_min      2.55
_cell_volume                     4466.1(15)
_computing_cell_refinement       'DirAx (Duisenberg 1992)'
_computing_data_collection       'COLLECT (Nonius, 2002)'
_computing_data_reduction        'COLLECT/EVAL (Nonius, 2002)'
_computing_molecular_graphics    'SHELXTL (Sheldrick, 1990)'
_computing_publication_material  'SHELXTL (Sheldrick, 1990)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.963
_diffrn_measured_fraction_theta_max 0.963
_diffrn_measurement_device_type  KappaCCD
_diffrn_measurement_method       \w-scan
_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  0.1536
_diffrn_reflns_av_sigmaI/netI    0.1337
_diffrn_reflns_limit_h_max       19
_diffrn_reflns_limit_h_min       -19
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -6
_diffrn_reflns_limit_l_max       53
_diffrn_reflns_limit_l_min       -53
_diffrn_reflns_number            45709
_diffrn_reflns_theta_full        25.10
_diffrn_reflns_theta_max         25.10
_diffrn_reflns_theta_min         2.58
_exptl_absorpt_coefficient_mu    0.132
_exptl_absorpt_correction_T_max  0.9921
_exptl_absorpt_correction_T_min  0.9741
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 1996)'
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.560
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             2128
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.08
_exptl_crystal_size_min          0.06
_refine_diff_density_max         0.465
_refine_diff_density_min         -0.402
_refine_diff_density_rms         0.091
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.113
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     685
_refine_ls_number_reflns         7690
_refine_ls_number_restraints     24
_refine_ls_restrained_S_all      1.119
_refine_ls_R_factor_all          0.2212
_refine_ls_R_factor_gt           0.1260
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0709P)^2^+26.3081P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2388
_refine_ls_wR_factor_ref         0.2807
_reflns_number_gt                4215
_reflns_number_total             7690
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b803817a.txt
_cod_data_source_block           rgc09
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               7103250