Supramolecular synthons based on N–H⋯N and C–H⋯O hydrogen bonds. Crystal engineering of a helical structure with 5,5-diethylbarbituric acid
Vishweshwar, Peddy; Thaimattam, Ram; Jaskólski, Mariusz; Desiraju, Gautam R.; Chemical Communications  (2002) 1830–1831; doi:10.1039/b204388b

data_7114481
_publ_section_title
;
 Supramolecular synthons based on N--H&#x22ef;N and C--H&#x22ef;O hydrogen 
 bonds. Crystal engineering of a helical structure with 5,5-diethylbarbituric
 acid
;
_journal_issue                   17
_journal_name_full               'Chemical Communications'
_journal_page_first              1830
_journal_page_last               1831
_journal_paper_doi               10.1039/b204388b
_journal_year                    2002
_chemical_formula_sum            'C20 H20 N4 O3'
_chemical_formula_weight         364.40
_chemical_melting_point          434
_chemical_name_common
;
1:1 molecular complex of 5,5-diethylbarbituric acid and 1,10-phenanthroline
;
_chemical_name_systematic
;
1:1 molecular complex of 5,5-diethylbarbituric acid and 1,10-phenanthroline
;
_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_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 98.31(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   12.656(3)
_cell_length_b                   7.0140(14)
_cell_length_c                   20.665(4)
_cell_measurement_reflns_used    1300
_cell_measurement_temperature    100
_cell_volume                     1815.2(7)
_computing_data_collection       KUMA-1
_computing_data_reduction        'KM4-RED [KUMA-2]'
_computing_molecular_graphics    'PLUTON (Spek, 1992)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      100
_diffrn_measured_fraction_theta_full 0.982
_diffrn_measured_fraction_theta_max 0.982
_diffrn_measurement_device_type  'KUMA CCD detector [KUMA-1]'
_diffrn_measurement_method       '/w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0366
_diffrn_reflns_av_sigmaI/netI    0.0437
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_k_max       5
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       26
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            10474
_diffrn_reflns_theta_full        27.49
_diffrn_reflns_theta_max         27.49
_diffrn_reflns_theta_min         3.41
_exptl_absorpt_coefficient_mu    0.092
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.333
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             768
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.25
_refine_diff_density_max         0.323
_refine_diff_density_min         -0.188
_refine_diff_density_rms         0.049
_refine_ls_extinction_coef       0.018(2)
_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   1.197
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     325
_refine_ls_number_reflns         4096
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.197
_refine_ls_R_factor_all          0.0778
_refine_ls_R_factor_gt           0.0599
_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^)+(0.0505P)^2^+0.5730P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1172
_refine_ls_wR_factor_ref         0.1241
_reflns_number_gt                3539
_reflns_number_total             4096
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b204388b.txt
_cod_data_source_block           ph
_cod_depositor_comments
;
The following automatic conversions were performed:
'_atom_site_symetry_multiplicity' tag replaced with
'_atom_site_symmetry_multiplicity'.

Automatic conversion script
Id: cif_correct_tags 1440 2010-10-19 06:21:57Z saulius 

The following automatic conversions were performed:

'_cell_measurement_temperature' value '100K' was changed to '100' -
the value should be numeric and without a unit
designator.

'_diffrn_ambient_temperature' value '100K' was changed
to '100' - the value should be numeric and without a unit
designator.

'_chemical_melting_point' value '434 K' was changed to
'434' - the value should be numeric and without a unit
designator.

'_symmetry_cell_setting' value 'Monoclinic' changed to
'monoclinic' according to
/usr/data/users/saulius/automatic-downloads/retrospective/RSC/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 2281 2013-09-26 08:29:07Z andrius 
;
_cod_original_cell_volume        1815.1(6)
_cod_original_sg_symbol_H-M      P21/c
_cod_database_code               7114481