Inversion symmetry and local vs. dispersive interactions in the nucleation of hydrogen bonded cyclic n-mer and tape of imidazolecarboxamidines.
Long, Sihui; Muthusamy, Venkatraj; Willis, Peter G.; Parkin, Sean; Cammers, Arthur; Beilstein journal of organic chemistry 4 (2008) 23–; doi:10.3762/bjoc.4.23

data_4029736
_publ_section_title
;
 Inversion symmetry and local vs. dispersive interactions in the
 nucleation of hydrogen bonded cyclic n-mer and tape of
 imidazolecarboxamidines.
;
_journal_name_full               'Beilstein journal of organic chemistry'
_journal_page_first              23
_journal_paper_doi               10.3762/bjoc.4.23
_journal_volume                  4
_journal_year                    2008
_chemical_formula_moiety         'C18 H18 N4, 0.5(C4 H10 O)'
_chemical_formula_sum            'C20 H23 N4 O0.5'
_chemical_formula_weight         327.42
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 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                 93.0935(7)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   5.7147(1)
_cell_length_b                   13.9252(2)
_cell_length_c                   22.2681(3)
_cell_measurement_reflns_used    4233
_cell_measurement_temperature    90.0(2)
_cell_measurement_theta_max      27.48
_cell_measurement_theta_min      1.00
_cell_volume                     1769.48(5)
_computing_cell_refinement       'SCALEPACK (Otwinowski & Minor, 1997)'
_computing_data_collection       'COLLECT (Nonius, 1998)'
_computing_data_reduction        'DENZO-SMN (Otwinowski & Minor, 1997)'
_computing_molecular_graphics    'XP in SHELXTL (Sheldrick, 2008)'
_computing_publication_material
; 
SHELX97-2 (Sheldrick, 2008) and local procedures 
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      90.0(2)
_diffrn_detector_area_resol_mean 18
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Nonius KappaCCD diffractometer'
_diffrn_measurement_method       '\w scans at fixed \c = 55\%'
_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  0.0261
_diffrn_reflns_av_sigmaI/netI    0.0403
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -18
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            23516
_diffrn_reflns_theta_full        27.49
_diffrn_reflns_theta_max         27.49
_diffrn_reflns_theta_min         1.83
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.077
_exptl_absorpt_correction_T_max  0.985
_exptl_absorpt_correction_T_min  0.970
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Scalepack (Otwinowski & Minor, 1997)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.229
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             700
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.653
_refine_diff_density_min         -0.722
_refine_diff_density_rms         0.064
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.083
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     248
_refine_ls_number_reflns         4064
_refine_ls_number_restraints     71
_refine_ls_restrained_S_all      1.178
_refine_ls_R_factor_all          0.0849
_refine_ls_R_factor_gt           0.0617
_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^)+(0.0988P)^2^+1.0938P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1722
_refine_ls_wR_factor_ref         0.1904
_reflns_number_gt                2944
_reflns_number_total             4064
_reflns_threshold_expression     >2\s(I)
_cod_data_source_file            9b3_Ci.cif
_cod_data_source_block           k07239
_cod_original_sg_symbol_H-M      'P 21/n'
_cod_original_formula_sum        'C20 H23 N4 O0.50'
_cod_database_code               4029736