Unusual conformation of (<i>R</i>,<i>R</i>)-<i>N</i>,<i>N</i>,<i>N</i>',<i>N</i>'-tetramethyltartramide (I) and its <i>O</i>,<i>O</i>'-dibenzoyl derivative (II)
Rychlewska, U.; Acta Crystallographica Section C 48 (1992) 965–969; doi:10.1107/S0108270192000921

data_2000936
_publ_section_title
;Unusual conformation of
 (<i>R</i>,<i>R</i>)-<i>N</i>,<i>N</i>,<i>N</i>',<i>N</i>'-tetramethyltartramide
 (I) and its <i>O</i>,<i>O</i>'-dibenzoyl derivative (II)
;
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              965
_journal_page_last               969
_journal_paper_doi               10.1107/S0108270192000921
_journal_volume                  48
_journal_year                    1992
_chemical_formula_sum            'C8 H16 N2 O4'
_chemical_formula_weight         204.23
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  'P 32 2"'
_symmetry_space_group_name_H-M   'P 32 2 1'
_cell_angle_alpha                90.0
_cell_angle_beta                 90.0
_cell_angle_gamma                120.0
_cell_formula_units_Z            3
_cell_length_a                   9.4370(10)
_cell_length_b                   9.4370(10)
_cell_length_c                   10.6900(10)
_cell_measurement_reflns_used    15
_cell_measurement_temperature    295
_cell_measurement_theta_max      16.8
_cell_measurement_theta_min      12.6
_cell_volume                     824.47(15)
_diffrn_measurement_device       'Syntex P2~1~'
_diffrn_measurement_method       \q/2\q
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.028
_diffrn_reflns_limit_h_max       0
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            1667
_diffrn_reflns_theta_max         58
_diffrn_standards_decay_%        .0
_diffrn_standards_interval_time  100
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    0.796
_exptl_crystal_colour            Transparent
_exptl_crystal_density_diffrn    1.23
_exptl_crystal_density_meas      1.23
_exptl_crystal_description       Cube
_exptl_crystal_size_max          0.35
_exptl_crystal_size_mid          0.35
_exptl_crystal_size_min          0.3
_refine_diff_density_max         0.27
_refine_diff_density_min         -0.22
_refine_ls_extinction_coef       2.0(1)x10^-5^
_refine_ls_extinction_method     'F^*^~c~=F~c~(1 -- xF^2^~c~/sin\q)'
_refine_ls_goodness_of_fit_obs   4.0
_refine_ls_hydrogen_treatment    refall
_refine_ls_number_parameters     80
_refine_ls_number_reflns         734
_refine_ls_R_factor_obs          0.035
_refine_ls_shift/esd_max         0.12
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     'w = 1/(\s^2^~F~+0.0001F^2^)'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_obs         0.050
_reflns_number_observed          736
_reflns_number_total             767
_reflns_observed_criterion       I>=1.96\s(I)
_cod_data_source_file            ab1002.cif
_cod_data_source_block           ab1002a
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Trigonal' changed to 'trigonal' according
to '/home/saulius/struct/CIF-dictionaries/cif_core.dic' dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 

The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Trigonal' changed to 'trigonal'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value '1/(\s^2^~F~+0.0001F^2^)' was
changed to 'calc'. New tag '_refine_ls_weighting_details' was
created. The value of the new tag was set to 'w =
1/(\s^2^~F~+0.0001F^2^)'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        824.50(10)
_cod_database_code               2000936