The formation of thymidine-based T-tetramers with remarkable structural and metal ion size effects.
Luo, Qun; Wu, Dayong; Liu, Shixiong; Tang, Daihua; Huang, Yong; Liu, Xinhou; Wang, Fuyi; Wang, Ruiyao; Wu, Gang; Organic & biomolecular chemistry 9 (2011) 1030–1033; doi:10.1039/C0OB00520G

data_7151649
_publ_section_title
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 The formation of thymidine-based T-tetramers with remarkable
 structural and metal ion size effects.
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_journal_issue                   4
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              1030
_journal_page_last               1033
_journal_paper_doi               10.1039/C0OB00520G
_journal_volume                  9
_journal_year                    2011
_chemical_absolute_configuration ad
_chemical_formula_sum            'C18 H30 N2 O6 Si'
_chemical_formula_weight         398.53
_chemical_name_common            DHT-T2
_space_group_IT_number           20
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'C 2c 2'
_symmetry_space_group_name_H-M   'C 2 2 21'
_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                90.00
_cell_formula_units_Z            8
_cell_length_a                   10.9379(17)
_cell_length_b                   12.550(2)
_cell_length_c                   31.289(5)
_cell_measurement_temperature    180(2)
_cell_volume                     4295.1(12)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_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      180(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'CCD area detector'
_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  0.0207
_diffrn_reflns_av_sigmaI/netI    0.0229
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       38
_diffrn_reflns_limit_l_min       -37
_diffrn_reflns_number            13702
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         26.00
_diffrn_reflns_theta_min         1.30
_exptl_absorpt_coefficient_mu    0.143
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.7367
_exptl_absorpt_correction_type   'Empirical (Bruker SADABS)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.233
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1712
_exptl_crystal_size_max          0.5
_exptl_crystal_size_mid          0.5
_exptl_crystal_size_min          0.2
_refine_diff_density_max         0.193
_refine_diff_density_min         -0.179
_refine_diff_density_rms         0.034
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.00(10)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.027
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     251
_refine_ls_number_reflns         3969
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.027
_refine_ls_R_factor_all          0.0302
_refine_ls_R_factor_gt           0.0270
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0462P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0694
_refine_ls_wR_factor_ref         0.0705
_reflns_number_gt                3647
_reflns_number_total             3969
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            C0OB00520G.TXT
_cod_data_source_block           aw84
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Orthorhombic' changed to 'orthorhombic'
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 1555 2011-01-17 13:19:09Z saulius 
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_cod_original_sg_symbol_H-M      C222(1)
_cod_database_code               7151649