A double helix is the repeating unit in a luminescent calcium 5-aminoisophthalate supramolecular edifice with water-filled hexagonal channels.
Murugavel, Ramaswamy; Kumar, Parimal; Walawalkar, Mrinalini G.; Mathialagan, Ramyaa; Inorganic chemistry 46 (2007) 6828–6830; doi:10.1021/ic070113k

data_4339846
_publ_section_title
;
 A double helix is the repeating unit in a luminescent calcium
 5-aminoisophthalate supramolecular edifice with water-filled hexagonal
 channels.
;
_journal_issue                   17
_journal_name_full               'Inorganic chemistry'
_journal_page_first              6828
_journal_page_last               6830
_journal_paper_doi               10.1021/ic070113k
_journal_volume                  46
_journal_year                    2007
_chemical_formula_moiety         'C8 H15 Ca1 N1 O9'
_chemical_formula_sum            'C8 H15 Ca N O9'
_chemical_formula_weight         309.29
_chemical_melting_point          3
_chemical_name_common            Ca-5-aminoisophthalate
_chemical_name_systematic
;
 ?
;
_space_group_IT_number           148
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  '-R 3'
_symmetry_space_group_name_H-M   'R -3 :H'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.000
_cell_angle_beta                 90.000
_cell_angle_gamma                120.000
_cell_formula_units_Z            18
_cell_length_a                   23.6920(17)
_cell_length_b                   23.6920(17)
_cell_length_c                   13.3740(15)
_cell_measurement_reflns_used    0
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      0
_cell_measurement_theta_min      0
_cell_volume                     6501.2(10)
_computing_cell_refinement       'CAD4 Express (Enraf Nonius, 1994)'
_computing_data_collection       'CAD4 Express (Enraf Nonius, 1994)'
_computing_data_reduction        'XCAD4 (Harms & Wocadlo, 1995)'
_computing_molecular_graphics    'Ortep-3 for Windows (Farrugia, 1997)'
_computing_publication_material  'WinGX publication routines (Farrugia, 1999)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-86 (Sheldrick, 1986)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Enraf Nonius TurboCAD4'
_diffrn_measurement_method       'non-profiled omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
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_diffrn_reflns_limit_h_min       0
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_diffrn_reflns_limit_l_max       0
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_diffrn_reflns_theta_full        24.98
_diffrn_reflns_theta_max         24.98
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_diffrn_standards_decay_%        -1
_diffrn_standards_interval_time  60
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.472
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.422
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
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_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.2
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_refine_ls_extinction_method     none
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_refine_ls_matrix_type           full
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_refine_ls_number_reflns         2542
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.060
_refine_ls_R_factor_all          0.0814
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_refine_ls_shift/su_max          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^)+(0.1172P)^2^+26.6923P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1752
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_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ic070113k-file001.cif
_cod_data_source_block           rm154z_(compound_1)
_cod_original_sg_symbol_H-M      'R -3'
_cod_database_code               4339846