Extreme oxatriquinanes and a record C-O bond length.
Gunbas, Gorkem; Hafezi, Nema; Sheppard, William L; Olmstead, Marilyn M; Stoyanova, Irini V; Tham, Fook S; Meyer, Matthew P; Mascal, Mark; Nature chemistry 4 (2012) 1018–1023; doi:10.1038/nchem.1502

data_1509133
_publ_section_title
;
 Extreme oxatriquinanes and a record C-O bond length.
;
_journal_issue                   12
_journal_name_full               'Nature chemistry'
_journal_page_first              1018
_journal_page_last               1023
_journal_paper_doi               10.1038/nchem.1502
_journal_volume                  4
_journal_year                    2012
_chemical_formula_moiety         'C18 H33 O , P F6'
_chemical_formula_sum            'C18 H33 F6 O P'
_chemical_formula_weight         410.41
_chemical_melting_point          492
_chemical_name_systematic
; 
 1,4,7- tri-iso-propyloxatriquinanium Hexafluorophosphate
;
_space_group_IT_number           161
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  'R 3 -2"c'
_symmetry_space_group_name_H-M   'R 3 c :H'
_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                 90.00
_cell_angle_gamma                120.00
_cell_formula_units_Z            6
_cell_length_a                   10.2958(19)
_cell_length_b                   10.2958(19)
_cell_length_c                   32.340(6)
_cell_measurement_reflns_used    9922
_cell_measurement_temperature    90(2)
_cell_measurement_theta_max      31.6
_cell_measurement_theta_min      2.6
_cell_volume                     2968.9(10)
_computing_cell_refinement       'SAINT (Bruker, 2011)'
_computing_data_collection       'Apex2 (Bruker, 2011)'
_computing_data_reduction        'SAINT (Bruker, 2011)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      90(2)
_diffrn_detector_area_resol_mean 8.3
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker SMART DUO'
_diffrn_measurement_method       \w
_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  0.0189
_diffrn_reflns_av_sigmaI/netI    0.0115
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       47
_diffrn_reflns_limit_l_min       -47
_diffrn_reflns_number            15378
_diffrn_reflns_theta_full        31.61
_diffrn_reflns_theta_max         31.61
_diffrn_reflns_theta_min         2.61
_exptl_absorpt_coefficient_mu    0.198
_exptl_absorpt_correction_T_max  0.9843
_exptl_absorpt_correction_T_min  0.9250
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 2008)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.377
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             1308
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.251
_refine_diff_density_min         -0.186
_refine_diff_density_rms         0.033
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.01(6)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.019
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     81
_refine_ls_number_reflns         2208
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.019
_refine_ls_R_factor_all          0.0194
_refine_ls_R_factor_gt           0.0191
_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^)+(0.0449P)^2^+0.3179P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0564
_refine_ls_wR_factor_ref         0.0568
_reflns_number_gt                2180
_reflns_number_total             2208
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            nchem.1502-s4.cif
_cod_data_source_block           gg02
_cod_original_cell_volume        2968.8(10)
_cod_original_sg_symbol_H-M      'R 3c'
_cod_database_code               1509133