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_4029771
_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_sum            'C20 H22 N4'
_chemical_formula_weight         318.42
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                87.4755(6)
_cell_angle_beta                 70.5173(6)
_cell_angle_gamma                76.4271(6)
_cell_formula_units_Z            2
_cell_length_a                   9.32870(10)
_cell_length_b                   9.47900(10)
_cell_length_c                   10.4921(2)
_cell_measurement_reflns_used    3811
_cell_measurement_temperature    90.0(2)
_cell_measurement_theta_max      27.48
_cell_measurement_theta_min      1.00
_cell_volume                     849.64(2)
_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, 1994)'
_computing_publication_material
; 
SHELX97-2 (Sheldrick, 1997) and local procedures 
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      90.0(2)
_diffrn_detector_area_resol_mean 18
_diffrn_measured_fraction_theta_full .998
_diffrn_measured_fraction_theta_max .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  0.0217
_diffrn_reflns_av_sigmaI/netI    0.0329
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            7568
_diffrn_reflns_theta_full        27.47
_diffrn_reflns_theta_max         27.47
_diffrn_reflns_theta_min         2.06
_exptl_absorpt_coefficient_mu    0.076
_exptl_absorpt_correction_T_max  0.9943
_exptl_absorpt_correction_T_min  0.9850
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Scalepack (Otwinowski & Minor, 1997)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.245
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       'square slab'
_exptl_crystal_F_000             340
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.08
_refine_diff_density_max         .229
_refine_diff_density_min         -.269
_refine_diff_density_rms         .044
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.058
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     221
_refine_ls_number_reflns         3876
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.058
_refine_ls_R_factor_all          0.0538
_refine_ls_R_factor_gt           0.0421
_refine_ls_shift/su_max          0.010
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0532P)^2^+0.2889P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1057
_refine_ls_wR_factor_ref         0.1137
_reflns_number_gt                3141
_reflns_number_total             3876
_reflns_threshold_expression     >2\s(I)
_cod_data_source_file            5b_Ci.cif
_cod_data_source_block           k05292
_cod_database_code               4029771