The Role of Weak Interactions in the Phase Transition and Distinct Mechanical Behavior of Two Structurally Similar Caffeine Co-crystal Polymorphs Studied by Nanoindentation
Ghosh, Soumyajit; Mondal, Arobendo; Kiran, M. S. R. N.; Ramamurty, U.; Reddy, C. Malla; Crystal Growth & Design 13 (2013) 4435–; doi:10.1021/cg400928v

data_4508259
_publ_section_title
;
 The Role of Weak Interactions in the Phase Transition and Distinct
 Mechanical Behavior of Two Structurally Similar Caffeine Co-crystal
 Polymorphs Studied by Nanoindentation
;
_journal_issue                   10
_journal_name_full               'Crystal Growth &amp; Design'
_journal_page_first              4435
_journal_paper_doi               10.1021/cg400928v
_journal_volume                  13
_journal_year                    2013
_chemical_formula_moiety         'C8 H10 N4 O2, C7 H4 Cl1 N1 O4'
_chemical_formula_sum            'C15 H14 Cl N5 O6'
_chemical_formula_weight         395.76
_chemical_melting_point          410.7
_chemical_name_common            'Caffeine:4-chloro-3nitrobenzoic acid'
_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                68.3770(10)
_cell_angle_beta                 86.8970(10)
_cell_angle_gamma                62.7300(10)
_cell_formula_units_Z            2
_cell_length_a                   9.8561(5)
_cell_length_b                   9.9591(5)
_cell_length_c                   10.7056(5)
_cell_measurement_reflns_used    8158
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      24.96
_cell_measurement_theta_min      2.49
_cell_volume                     859.91(7)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'BRUKER KAPPA APEX II DUO'
_diffrn_measurement_method       'phi and omega scans'
_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  0.0228
_diffrn_reflns_av_sigmaI/netI    0.0175
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            11740
_diffrn_reflns_theta_full        24.98
_diffrn_reflns_theta_max         24.98
_diffrn_reflns_theta_min         2.07
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.268
_exptl_absorpt_correction_T_max  0.918
_exptl_absorpt_correction_T_min  0.851
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'multi-scan absorption correction'
_exptl_crystal_colour            'pale yellow'
_exptl_crystal_density_diffrn    1.528
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             408
_exptl_crystal_size_max          0.60
_exptl_crystal_size_mid          0.55
_exptl_crystal_size_min          0.32
_refine_diff_density_max         1.027
_refine_diff_density_min         -0.525
_refine_diff_density_rms         0.054
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.047
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     255
_refine_ls_number_reflns         2995
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.047
_refine_ls_R_factor_all          0.0604
_refine_ls_R_factor_gt           0.0561
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0814P)^2^+0.7046P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1518
_refine_ls_wR_factor_ref         0.1575
_reflns_number_gt                2703
_reflns_number_total             2995
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            cg400928v_si_003.cif
_cod_data_source_block           cmr_sg_081_1
_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 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 1891 2012-01-12 08:04:46Z andrius 
;
_cod_original_sg_symbol_H-M      'P-1   '
_cod_database_code               4508259