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_7051911
_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           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_conform_dict_location     ftp://ftp.iucr.org/pub/cif_core.dic
_audit_conform_dict_name         cif_core.dic
_audit_conform_dict_version      2.3
_audit_creation_date             2007-12-29T18:04:50-00:00
_audit_creation_method           'WinGX routine CIF_UPDATE'
_cell_angle_alpha                90.000
_cell_angle_beta                 107.010(2)
_cell_angle_gamma                90.000
_cell_formula_units_Z            8
_cell_length_a                   18.4176(19)
_cell_length_b                   13.8286(14)
_cell_length_c                   11.2744(12)
_cell_measurement_reflns_used    5344
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      27.5
_cell_measurement_theta_min      2.3
_cell_volume                     2745.9(5)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.937
_diffrn_measured_fraction_theta_max 0.937
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0352
_diffrn_reflns_av_unetI/netI     0.0432
_diffrn_reflns_limit_h_max       26
_diffrn_reflns_limit_h_min       -26
_diffrn_reflns_limit_k_max       20
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            30420
_diffrn_reflns_theta_full        31.98
_diffrn_reflns_theta_max         31.98
_diffrn_reflns_theta_min         1.16
_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          0.2
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.1
_refine_diff_density_max         0.218
_refine_diff_density_min         -0.166
_refine_diff_density_rms         0.035
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.029
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     493
_refine_ls_number_reflns         8931
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.029
_refine_ls_R_factor_all          0.1075
_refine_ls_R_factor_gt           0.0486
_refine_ls_shift/su_max          0.005
_refine_ls_shift/su_mean         0.003
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0610P)^2^+0.3348P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1217
_refine_ls_wR_factor_ref         0.1489
_reflns_number_gt                4781
_reflns_number_total             8931
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b800050f.txt
_cod_data_source_block           2-I
_cod_database_code               7051911