3,6-dibenzyl-1,4-dimethylpiperazine-2,5-dione
Croft, Anna K.; Foley, Mark K.; Horton, Peter N.; Hursthouse, Michael B.; Crystal Structure Report Archive  (2003) 877–; doi:

data_1519550
_publ_section_title
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 3,6-dibenzyl-1,4-dimethylpiperazine-2,5-dione
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_journal_name_full               'Crystal Structure Report Archive'
_journal_page_first              877
_journal_year                    2003
_chemical_formula_moiety         'C20 H22 N2 O2'
_chemical_formula_sum            'C20 H22 N2 O2'
_chemical_formula_weight         322.40
_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
_cell_angle_alpha                90.00
_cell_angle_beta                 100.254(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   15.2187(13)
_cell_length_b                   14.3684(10)
_cell_length_c                   7.6880(6)
_cell_measurement_reflns_used    3787
_cell_measurement_temperature    120(2)
_cell_measurement_theta_max      27.485
_cell_measurement_theta_min      2.910
_cell_volume                     1654.3(2)
_computing_cell_refinement
' DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998)'
_computing_data_collection       ' DENZO (Otwinowski and Minor, 1997)'
_computing_data_reduction
' DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998)'
_computing_molecular_graphics    'PLATON (Spek, 1990)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997b)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997a)'
_diffrn_ambient_temperature      120(2)
_diffrn_detector_area_resol_mean 9.091
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_diffrn_measurement_device_type  'Nonius KappaCCD Area Detector'
_diffrn_measurement_method       '\f and \w scans to fill Ewald Sphere'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'Nonius FR591 rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0981
_diffrn_reflns_av_sigmaI/netI    0.0936
_diffrn_reflns_limit_h_max       19
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -18
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            19071
_diffrn_reflns_theta_full        27.50
_diffrn_reflns_theta_max         27.50
_diffrn_reflns_theta_min         3.04
_exptl_absorpt_coefficient_mu    0.084
_exptl_absorpt_correction_T_max  0.9966
_exptl_absorpt_correction_T_min  0.9768
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SORTAV Blessing (1997)'
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.294
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Plate
_exptl_crystal_F_000             688
_exptl_crystal_size_max          0.28
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.193
_refine_diff_density_min         -0.227
_refine_diff_density_rms         0.051
_refine_ls_extinction_coef       0.028(3)
_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   0.991
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     220
_refine_ls_number_reflns         3763
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.991
_refine_ls_R_factor_all          0.1231
_refine_ls_R_factor_gt           0.0519
_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^)+(0.0516P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0974
_refine_ls_wR_factor_ref         0.1187
_reflns_number_gt                2098
_reflns_number_total             3763
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            eCrystal-877.cif
_cod_data_source_block           s93
_cod_depositor_comments
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Citation :
Croft, Anna K. and Foley, Mark K. and Horton, Peter N. and 
Hursthouse, Michael B. (2003) 
University of Southampton, Crystal Structure Report Archive. 
(doi:10.5258/ecrystals/877)

More at:
http://ecrystals.chem.soton.ac.uk/877/

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 3271 2015-04-21 07:52:19Z andrius 
;
_cod_original_sg_symbol_H-M      P2(1)/c
_cod_database_code               1519550