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_1503529
_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_formula_sum            'C20 H18 N2'
_chemical_formula_weight         286.36
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.000
_cell_angle_beta                 90.000
_cell_angle_gamma                90.000
_cell_formula_units_Z            4
_cell_length_a                   6.1520(14)
_cell_length_b                   9.7480(13)
_cell_length_c                   26.381(4)
_cell_measurement_reflns_used    17992
_cell_measurement_temperature    122(2)
_cell_measurement_theta_max      32.43
_cell_measurement_theta_min      1.54
_cell_volume                     1582.1(5)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      122(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_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  0.0702
_diffrn_reflns_av_sigmaI/netI    0.0397
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       39
_diffrn_reflns_limit_l_min       -39
_diffrn_reflns_number            50288
_diffrn_reflns_theta_full        32.43
_diffrn_reflns_theta_max         32.43
_diffrn_reflns_theta_min         1.54
_exptl_absorpt_coefficient_mu    0.071
_exptl_absorpt_correction_T_max  0.992
_exptl_absorpt_correction_T_min  0.967
_exptl_absorpt_correction_type   integration
_exptl_absorpt_process_details
;
Gaussian integration (Coppens, 1970) 
;
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.202
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Prism
_exptl_crystal_F_000             608
_exptl_crystal_size_max          0.32
_exptl_crystal_size_mid          0.21
_exptl_crystal_size_min          0.14
_refine_diff_density_max         0.271
_refine_diff_density_min         -0.247
_refine_diff_density_rms         0.057
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.090
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     199
_refine_ls_number_reflns         3267
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.090
_refine_ls_R_factor_all          0.0599
_refine_ls_R_factor_gt           0.0456
_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^)+(0.0526P)^2^+0.3650P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1033
_refine_ls_wR_factor_ref         0.1104
_reflns_number_gt                2793
_reflns_number_total             3267
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol2030586_si_001.cif
_cod_data_source_block           shelxl
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_database_code               1503529