A monoclinic polymorph of theophylline
Zhang, Shuo; Fischer, Andreas; Acta Crystallographica Section E 67 (2011) o3357–; doi:10.1107/S1600536811047532

data_2232996
_publ_section_title
;
 A monoclinic polymorph of theophylline
;
_journal_coeditor_code           WN2455
_journal_issue                   12
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o3357
_journal_paper_doi               10.1107/S1600536811047532
_journal_volume                  67
_journal_year                    2011
_chemical_formula_iupac          'C7 H8 N4 O2'
_chemical_formula_moiety         'C7 H8 N4 O2'
_chemical_formula_sum            'C7 H8 N4 O2'
_chemical_formula_weight         180.167
_chemical_name_common            theophylline
_chemical_name_systematic
;
1,3-dimethyl-7<i>H</i>-purine-2,6-dione
;
_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_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.00
_cell_angle_beta                 104.214(5)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   7.8935(6)
_cell_length_b                   12.9087(7)
_cell_length_c                   15.9055(8)
_cell_measurement_reflns_used    82
_cell_measurement_temperature    299
_cell_measurement_theta_max      20.8
_cell_measurement_theta_min      4.2
_cell_volume                     1571.07(17)
_computing_cell_refinement       'DIRAX (Duisenberg, 1992)'
_computing_data_collection       'COLLECT (Nonius, 1998)'
_computing_data_reduction        'EVALCCD (Duisenberg <i>et al.</i>, 2003)'
_computing_molecular_graphics    'DIAMOND (Brandenburg, 2007)'
_computing_publication_material  'publCIF (Westrip, 2010)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      299
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device       'Bruker--Nonius KappaCCD'
_diffrn_measurement_method       \w
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_reflns_av_R_equivalents  0.058
_diffrn_reflns_av_sigmaI/netI    0.037
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            19027
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         26.00
_diffrn_reflns_theta_min         4.54
_exptl_absorpt_coefficient_mu    0.117
_exptl_absorpt_correction_T_max  0.995
_exptl_absorpt_correction_T_min  0.863
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
(SADABS; Sheldrick, 2003)
;
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.523
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Plate
_exptl_crystal_F_000             752
_exptl_crystal_size_max          0.35
_exptl_crystal_size_mid          0.29
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.222
_refine_diff_density_min         -0.244
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.05
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     239
_refine_ls_number_reflns         3074
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.05
_refine_ls_R_factor_all          0.090
_refine_ls_R_factor_gt           0.048
_refine_ls_shift/su_max_lt       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^)+(0.0593P)^2^+0.4941P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.110
_refine_ls_wR_factor_ref         0.129
_reflns_number_gt                1972
_reflns_number_total             3074
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            wn2455.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               2232996
_cod_database_fobs_code          2232996