With regard to the hydrogen bonding in complexes of pyridylureas, less is more. a role for shape complementarity and CH...O interactions?
Quinn, Jordan R.; Zimmerman, Steven C.; Organic letters 6 (2004) 1649–1652; doi:10.1021/ol0495016

data_1507099
_publ_contact_author
; 
Steven C. Zimmerman 
University of Illinois 
Department of Chemistry, MC-712 
600 South Mathews Avenue 
Urbana, Illinois  61801 
USA 
;
_publ_section_title
;
 With regard to the hydrogen bonding in complexes of pyridylureas, less is
 more. a role for shape complementarity and CH...O interactions?
;
_journal_issue                   10
_journal_name_full               'Organic letters'
_journal_page_first              1649
_journal_page_last               1652
_journal_paper_doi               10.1021/ol0495016
_journal_volume                  6
_journal_year                    2004
_chemical_formula_moiety         'C18 H14 N4 O2, C11 H17 N3 O'
_chemical_formula_sum            'C29 H31 N7 O3'
_chemical_formula_weight         525.61
_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
_audit_update_record
; 
2004-02-21   text and data added, srw 
;
_cell_angle_alpha                93.396(5)
_cell_angle_beta                 96.415(4)
_cell_angle_gamma                113.477(4)
_cell_formula_units_Z            2
_cell_length_a                   10.895(3)
_cell_length_b                   10.970(3)
_cell_length_c                   12.255(3)
_cell_measurement_reflns_used    821
_cell_measurement_temperature    193(2)
_cell_measurement_theta_max      27.25
_cell_measurement_theta_min      2.23
_cell_volume                     1326.4(6)
_computing_cell_refinement       'SAINT V6.22 (Bruker, 2001)'
_computing_data_collection       'SMART V5.625 (Bruker, 2001)'
_computing_data_reduction        'SAINT V6.22 (Bruker, 2001)'
_computing_molecular_graphics    'SHELXTL V6.10 (Bruker, 2001)'
_computing_publication_material  'CIFTAB (Sheldrick, 2001)'
_computing_structure_refinement  'SHELXTL V6.10 (Bruker, 2001)'
_computing_structure_solution    'SHELXTL V6.10 (Bruker, 2001)'
_diffrn_ambient_temperature      193(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device       'Siemens Platform/CCD'
_diffrn_measurement_method       'profile data from \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'normal-focus sealed tube'
_diffrn_radiation_type           MoK\a
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_diffrn_reflns_av_R_equivalents  0.0590
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_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            13815
_diffrn_reflns_theta_full        25.39
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_diffrn_reflns_theta_min         1.68
_diffrn_standards_decay_%        4.2
_diffrn_standards_interval_time  365
_diffrn_standards_number         51
_exptl_absorpt_coefficient_mu    0.089
_exptl_absorpt_correction_T_max  0.9936
_exptl_absorpt_correction_T_min  0.9747
_exptl_absorpt_correction_type   integration
_exptl_absorpt_process_details   '(Bruker, 2001)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.316
_exptl_crystal_density_meas      ?
_exptl_crystal_description       tabular
_exptl_crystal_F_000             556
_exptl_crystal_id                p83zac
_exptl_crystal_preparation
; 
The data crystal was mounted using oil (Parantone-N, Exxon) to a 
0.4 mm cryo-loop (Hampton Research) with the (0 1 1) scattering planes 
roughly normal to the spindle axis. 
;
_exptl_crystal_size_max          0.36
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.09
_refine_diff_density_max         0.142
_refine_diff_density_min         -0.142
_refine_diff_density_rms         0.033
_refine_ls_extinction_coef       0.0055(9)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   0.882
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     469
_refine_ls_number_reflns         4849
_refine_ls_number_restraints     24
_refine_ls_restrained_S_all      0.881
_refine_ls_R_factor_all          0.0874
_refine_ls_R_factor_gt           0.0385
_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^)+(0.0437P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0806
_refine_ls_wR_factor_ref         0.0926
_reflns_number_gt                2725
_reflns_number_total             4849
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol0495016si20040316_094950.cif
_cod_data_source_block           p83zac
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Triclinic' changed to 'triclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 

The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'not measured' was changed to '?'
- the value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 
;
_cod_original_sg_symbol_Hall     '-P 1 '
_cod_original_sg_symbol_H-M      'P -1 '
_cod_database_code               1507099