Study of the chelating capacity of nucleobase analogs with biological interest: XRD structural study and ab initio molecular orbital calculations on 1-methyl and 1,6,7-trimethyllumazine
Acuña-Cueva, Esther R.; Faure, René; Jiménez-Pulido, Sonia B.; Moreno-Carretero, Miguel N.; Peña-Ruiz, Tomás; Journal of Molecular Structure 697 (2004) 65–; doi:10.1016/j.molstruc.2004.03.022

data_1549448
_publ_section_title
;
 Study of the chelating capacity of nucleobase analogs with biological
 interest: XRD structural study and ab initio molecular orbital
 calculations on 1-methyl and 1,6,7-trimethyllumazine
;
_journal_issue                   1-3
_journal_name_full               'Journal of Molecular Structure'
_journal_page_first              65
_journal_paper_doi               10.1016/j.molstruc.2004.03.022
_journal_volume                  697
_journal_year                    2004
_chemical_formula_sum            'C7 H6 N4 O2'
_chemical_formula_weight         178.16
_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
_cell_angle_alpha                90.00
_cell_angle_beta                 93.407(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   4.8200(2)
_cell_length_b                   9.7820(5)
_cell_length_c                   15.3230(9)
_cell_measurement_reflns_used    3755
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      29.575
_cell_measurement_theta_min      0.998
_cell_volume                     721.19(6)
_computing_cell_refinement       KappaCCD
_computing_data_collection       KappaCCD
_computing_data_reduction
'Denzo and Scalepak (Otwinowski & Minor, 1997)''
_computing_structure_refinement  'SHELXTL v 5.03'
_computing_structure_solution    'SHELXTL v 5.03'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.960
_diffrn_measured_fraction_theta_max 0.960
_diffrn_measurement_device_type  KappaCCD
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71070
_diffrn_reflns_av_R_equivalents  0.1029
_diffrn_reflns_av_sigmaI/netI    0.0958
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            6431
_diffrn_reflns_theta_full        29.60
_diffrn_reflns_theta_max         29.60
_diffrn_reflns_theta_min         2.66
_exptl_absorpt_coefficient_mu    0.126
_exptl_absorpt_correction_T_max  0.9937
_exptl_absorpt_correction_T_min  0.9057
_exptl_absorpt_correction_type   'Multiscan sortav Blessing (1995)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.641
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             368
_exptl_crystal_size_max          0.80
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.348
_refine_diff_density_min         -0.376
_refine_diff_density_rms         0.083
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.054
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     136
_refine_ls_number_reflns         1947
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.054
_refine_ls_R_factor_all          0.1250
_refine_ls_R_factor_gt           0.0756
_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^)+(0.0973P)^2^+0.3247P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1831
_refine_ls_wR_factor_ref         0.2070
_reflns_number_gt                1185
_reflns_number_total             1947
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            mlm.cif
_cod_data_source_block           shelxl
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to the built-in table from CIF Core dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 5642 2017-10-24 12:04:52Z antanas 
;
_cod_original_sg_symbol_H-M      ' P 21 / c'
_cod_database_code               1549448