The formation of a hydrated homochiral helix from an achiral zwitterionic salt, spontaneous chiral symmetry breaking and redox chromism of crystals.
Yao, Qing-Xia; Xuan, Wei-Min; Zhang, Hui; Tu, Chao-Yang; Zhang, Jie; Chemical communications (Cambridge, England) 34 (2008) 59–61; doi:10.1039/b815456b

data_7104109
_publ_section_title
;
 The formation of a hydrated homochiral helix from an achiral
 zwitterionic salt, spontaneous chiral symmetry breaking and redox
 chromism of crystals.
;
_journal_issue                   1
_journal_name_full
'Chemical communications (Cambridge, England)'
_journal_page_first              59
_journal_page_last               61
_journal_paper_doi               10.1039/b815456b
_journal_volume                  34
_journal_year                    2008
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C26 H20 N2 O4 5(H2 O)'
_chemical_formula_sum            'C26 H30 N2 O9'
_chemical_formula_weight         514.53
_chemical_name_systematic
;
?
;
_space_group_IT_number           154
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  'P 32 2"'
_symmetry_space_group_name_H-M   'P 32 2 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                120.00
_cell_formula_units_Z            3
_cell_length_a                   9.6710(4)
_cell_length_b                   9.6710(4)
_cell_length_c                   22.6740(17)
_cell_measurement_reflns_used    4655
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      27.4835
_cell_measurement_theta_min      2.4303
_cell_volume                     1836.54(17)
_computing_cell_refinement       'CrystalClear(Rigaku Corp.,2000)'
_computing_data_collection       'CrystalClear(Rigaku Corp.,2000)'
_computing_data_reduction        'CrystalClear(Rigaku Corp.,2000)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.987
_diffrn_measured_fraction_theta_max 0.987
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       CCD_Profile_fitting
_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  0.0246
_diffrn_reflns_av_sigmaI/netI    0.0133
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            13804
_diffrn_reflns_theta_full        27.47
_diffrn_reflns_theta_max         27.47
_diffrn_reflns_theta_min         4.21
_exptl_absorpt_coefficient_mu    0.106
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.8644
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(R.H. Blessing, 1995&1997)'
_exptl_crystal_colour            White
_exptl_crystal_density_diffrn    1.385
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Prism
_exptl_crystal_F_000             804
_exptl_crystal_size_max          0.3500
_exptl_crystal_size_mid          0.3000
_exptl_crystal_size_min          0.1800
_refine_diff_density_max         0.152
_refine_diff_density_min         -0.286
_refine_diff_density_rms         0.033
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.075
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     180
_refine_ls_number_reflns         1629
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.075
_refine_ls_R_factor_all          0.0457
_refine_ls_R_factor_gt           0.0431
_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^)+(0.0689P)^2^+0.2465P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1176
_refine_ls_wR_factor_ref         0.1195
_reflns_number_gt                1518
_reflns_number_total             1629
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b815456b.txt
_cod_data_source_block           1
_cod_depositor_comments
;
The following automatic conversions were performed:
'_exptl_absorpt_correction_type' value 'Multi-scan' changed to
'multi-scan' 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:

'_chemical_absolute_configuration' value ' unk ' changed to 'unk'
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 1646 2011-03-28 12:23:43Z adriana 
;
_cod_original_sg_symbol_Hall     P_32_2"
_cod_original_sg_symbol_H-M      P3(2)21
_cod_database_code               7104109