Measuring aromaticity with the dimethyldihydropyrene ring current probe. Experimental and computational studies of the fulvenes and the strongly antiaromatic cyclopentadienone reveal large Mills-Nixon-type bond localization effects. Synthesis of fulvene-fused dihydropyrenes.
Mitchell, Reginald H.; Zhang, Rui; Berg, David J.; Twamley, Brendan; Williams, Richard Vaughan; Journal of the American Chemical Society 131 (2009) 189–199; doi:10.1021/ja806427n

data_4101697
_publ_section_title
;
 Measuring aromaticity with the dimethyldihydropyrene ring current probe.
 Experimental and computational studies of the fulvenes and the strongly
 antiaromatic cyclopentadienone reveal large Mills-Nixon-type bond
 localization effects. Synthesis of fulvene-fused dihydropyrenes.
;
_journal_issue                   1
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              189
_journal_page_last               199
_journal_paper_doi               10.1021/ja806427n
_journal_volume                  131
_journal_year                    2009
_chemical_formula_moiety         'C29 H34 O'
_chemical_formula_sum            'C29 H34 O'
_chemical_formula_weight         398.56
_chemical_name_common            Cyclopentenone-tBuDHP
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_Int_Tables_number      2
_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                112.859(7)
_cell_angle_beta                 91.953(8)
_cell_angle_gamma                103.258(8)
_cell_formula_units_Z            2
_cell_length_a                   9.685(4)
_cell_length_b                   10.666(4)
_cell_length_c                   12.406(5)
_cell_measurement_reflns_used    2679
_cell_measurement_temperature    86(2)
_cell_measurement_theta_max      25.35
_cell_measurement_theta_min      2.14
_cell_volume                     1138.5(8)
_computing_cell_refinement       'Bruker SAINT+ v. 6.45a'
_computing_data_collection       'Bruker SMART v. 5.626'
_computing_data_reduction        'Bruker SAINT+ v. 6.45a'
_computing_molecular_graphics    'XP, Bruker SHELXTL v. 6.12'
_computing_publication_material  'XCIF, Bruker SHELXTL v. 6.12'
_computing_structure_refinement  'XL, Bruker SHELXTL v. 6.12'
_computing_structure_solution    'XS, Bruker SHELXTL v. 6.12'
_diffrn_ambient_temperature      86(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/Siemens SMART APEX'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0783
_diffrn_reflns_av_sigmaI/netI    0.0956
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            12286
_diffrn_reflns_theta_full        25.25
_diffrn_reflns_theta_max         25.25
_diffrn_reflns_theta_min         1.80
_diffrn_source                   'normal-focus sealed tube'
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.068
_exptl_absorpt_correction_T_max  0.9973
_exptl_absorpt_correction_T_min  0.9825
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Bruker, 2001)'
_exptl_crystal_colour            brown
_exptl_crystal_density_diffrn    1.162
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             432
_exptl_crystal_size_max          0.26
_exptl_crystal_size_mid          0.11
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.303
_refine_diff_density_min         -0.229
_refine_diff_density_rms         0.054
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.999
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     280
_refine_ls_number_reflns         4125
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.999
_refine_ls_R_factor_all          0.1308
_refine_ls_R_factor_gt           0.0668
_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^)+(0.0838P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1474
_refine_ls_wR_factor_ref         0.1758
_reflns_number_gt                2329
_reflns_number_total             4125
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            ja806427n_si_001.cif
_cod_data_source_block           compound4
_cod_original_cell_volume        1138.6(8)
_cod_database_code               4101697