A bis(heptafulvenyl)-dicyanoethylene thermoswitch with two sites for ring closure.
Broman, Søren Lindbæk; Petersen, Anne Ugleholdt; Tortzen, Christian Gregers; Vibenholt, Johan; Bond, Andrew D.; Nielsen, Mogens Brøndsted; Organic letters 14 (2012) 318–321; doi:10.1021/ol2030586

data_1503530
_publ_section_title
;
 A bis(heptafulvenyl)-dicyanoethylene thermoswitch with two sites for ring
 closure.
;
_journal_issue                   1
_journal_name_full               'Organic letters'
_journal_page_first              318
_journal_page_last               321
_journal_paper_doi               10.1021/ol2030586
_journal_volume                  14
_journal_year                    2012
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C18 H11 N2 +, B F4 -'
_chemical_formula_sum            'C18 H11 B F4 N2'
_chemical_formula_weight         342.10
_chemical_name_common            'Azulenium ion'
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 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                 110.215(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   6.9618(6)
_cell_length_b                   14.5124(12)
_cell_length_c                   8.2473(7)
_cell_measurement_reflns_used    4318
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      24.97
_cell_measurement_theta_min      2.87
_cell_volume                     781.92(12)
_computing_cell_refinement       'SAINT v.7.68a (Bruker, 2010)'
_computing_data_collection       'APEX2 v2010.1-2 (Bruker, 2010)'
_computing_data_reduction        SAINT
_computing_molecular_graphics    SHELXTL
_computing_publication_material  SHELXTL
_computing_structure_refinement  SHELXTL
_computing_structure_solution    'SHELXTL v.6.12 (Sheldrick, 2008)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.992
_diffrn_measured_fraction_theta_max 0.992
_diffrn_measurement_device_type  'Bruker Nonius X8APEX-II CCD'
_diffrn_measurement_method       '\w and \f scans'
_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  0.0272
_diffrn_reflns_av_sigmaI/netI    0.0190
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            8066
_diffrn_reflns_theta_full        25.03
_diffrn_reflns_theta_max         25.03
_diffrn_reflns_theta_min         3.60
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.119
_exptl_absorpt_correction_T_max  0.977
_exptl_absorpt_correction_T_min  0.772
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'TWINABS (Sheldrick, 2008)'
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.453
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             348
_exptl_crystal_size_max          0.35
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.415
_refine_diff_density_min         -0.318
_refine_diff_density_rms         0.055
_refine_ls_abs_structure_details
;
 In the absence of significant anomalous scattering effects,
 Friedel pairs have been merged as equivalent data
;
_refine_ls_extinction_coef       0.061(12)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.049
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     256
_refine_ls_number_reflns         2519
_refine_ls_number_restraints     20
_refine_ls_restrained_S_all      1.327
_refine_ls_R_factor_all          0.0421
_refine_ls_R_factor_gt           0.0398
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0729P)^2^+0.0643P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1039
_refine_ls_wR_factor_ref         0.1057
_reflns_number_gt                2371
_reflns_number_total             2519
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            ol2030586_si_002.cif
_cod_data_source_block           mb1114
_cod_original_cell_volume        781.92(11)
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               1503530