Synthesis, crystal structure and crystal packing of diaza[5]helicenes
Bazzini, Cristina; Caronna, Tullio; Fontana, Francesca; Macchi, Piero; Mele, Andrea; Natali Sora, Isabella; Panzeri, Walter; Sironi, Angelo; New Journal of Chemistry 32 (2008) 1710–; doi:10.1039/b800050f

data_7051910
_publ_section_title
;
 Synthesis, crystal structure and crystal packing of diaza[5]helicenes
;
_journal_issue                   10
_journal_name_full               'New Journal of Chemistry'
_journal_page_first              1710
_journal_paper_doi               10.1039/b800050f
_journal_volume                  32
_journal_year                    2008
_chemical_formula_sum            'C20 H12 N2'
_chemical_formula_weight         280.32
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   15.7823(7)
_cell_length_b                   8.7508(4)
_cell_length_c                   19.8826(9)
_cell_measurement_reflns_used    5356
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      24.1
_cell_measurement_theta_min      2.4
_cell_volume                     2745.9(2)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 1
_diffrn_measured_fraction_theta_max 1
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0525
_diffrn_reflns_av_unetI/netI     0.0215
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -17
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            24627
_diffrn_reflns_theta_full        23.25
_diffrn_reflns_theta_max         23.25
_diffrn_reflns_theta_min         2.05
_exptl_absorpt_coefficient_mu    0.081
_exptl_absorpt_correction_type   none
_exptl_crystal_density_diffrn    1.356
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             1168
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.1
_exptl_crystal_size_min          0.1
_refine_diff_density_max         0.201
_refine_diff_density_min         -0.264
_refine_diff_density_rms         0.059
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.303
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     247
_refine_ls_number_reflns         1965
_refine_ls_number_restraints     12
_refine_ls_restrained_S_all      1.298
_refine_ls_R_factor_all          0.0833
_refine_ls_R_factor_gt           0.0806
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0499P)^2^+3.7710P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1721
_refine_ls_wR_factor_ref         0.1736
_reflns_number_gt                1893
_reflns_number_total             1965
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b800050f.txt
_cod_data_source_block           1
_cod_database_code               7051910