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_7051912
_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           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/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             2007-12-29T18:29:16-00:00
_audit_creation_method           'WinGX routine CIF_UPDATE'
_cell_angle_alpha                90
_cell_angle_beta                 92.2800(10)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   20.3520(6)
_cell_length_b                   9.0912(3)
_cell_length_c                   7.5400(2)
_cell_measurement_reflns_used    1852
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      23.7
_cell_measurement_theta_min      2.5
_cell_volume                     1393.98(7)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.945
_diffrn_measured_fraction_theta_max 0.945
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0606
_diffrn_reflns_av_unetI/netI     0.0574
_diffrn_reflns_limit_h_max       30
_diffrn_reflns_limit_h_min       -30
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            14182
_diffrn_reflns_theta_full        32.81
_diffrn_reflns_theta_max         32.81
_diffrn_reflns_theta_min         2
_exptl_absorpt_coefficient_mu    0.079
_exptl_absorpt_correction_type   none
_exptl_crystal_density_diffrn    1.336
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             584
_exptl_crystal_size_max          0.3
_exptl_crystal_size_mid          0.1
_exptl_crystal_size_min          0.1
_refine_diff_density_max         0.306
_refine_diff_density_min         -0.205
_refine_diff_density_rms         0.044
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.01
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     100
_refine_ls_number_reflns         2434
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.01
_refine_ls_R_factor_all          0.151
_refine_ls_R_factor_gt           0.0553
_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^)+(0.0550P)^2^+1.2465P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1256
_refine_ls_wR_factor_ref         0.1768
_reflns_number_gt                1163
_reflns_number_total             2434
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b800050f.txt
_cod_data_source_block           2-II
_cod_database_code               7051912