Quartet formation of a guanine derivative with an isopropyl group: crystal structures of "naked" G-quartets and thermodynamics of G-quartet formation.
Inui, Yuji; Shiro, Motoo; Fukuzumi, Shunichi; Kojima, Takahiko; Organic & biomolecular chemistry 11 (2013) 758–764; doi:10.1039/c2ob26877a

data_7152780
_publ_section_title
;
 Quartet formation of a guanine derivative with an isopropyl group:
 crystal structures of &quot;naked&quot; G-quartets and thermodynamics of
 G-quartet formation.
;
_journal_issue                   5
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              758
_journal_page_last               764
_journal_paper_doi               10.1039/c2ob26877a
_journal_volume                  11
_journal_year                    2013
_chemical_formula_moiety         2(C8H11N5O1)Ca0.5Cl
_chemical_formula_sum            'C16 H22 Ca0.5 Cl N10 O2'
_chemical_formula_weight         441.93
_chemical_name_systematic
;
?
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 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                 99.8840(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   8.9942(5)
_cell_length_b                   17.9689(11)
_cell_length_c                   12.8636(8)
_cell_measurement_temperature    90(2)
_cell_volume                     2048.1(2)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      90(2)
_diffrn_measured_fraction_theta_full 0.977
_diffrn_measured_fraction_theta_max 0.977
_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  0.0170
_diffrn_reflns_av_sigmaI/netI    0.0214
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            11513
_diffrn_reflns_theta_full        27.55
_diffrn_reflns_theta_max         27.55
_diffrn_reflns_theta_min         1.97
_exptl_absorpt_coefficient_mu    0.348
_exptl_absorpt_correction_T_max  0.9828
_exptl_absorpt_correction_T_min  0.9660
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS V2008/1 (Bruker AXS)'
_exptl_crystal_colour            noncolor
_exptl_crystal_density_diffrn    1.433
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       chip
_exptl_crystal_F_000             924
_exptl_crystal_size_max          0.10
_exptl_crystal_size_mid          0.09
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.474
_refine_diff_density_min         -0.304
_refine_diff_density_rms         0.049
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.050
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     272
_refine_ls_number_reflns         4614
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.050
_refine_ls_R_factor_all          0.0350
_refine_ls_R_factor_gt           0.0304
_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^)+(0.0348P)^2^+1.1119P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0753
_refine_ls_wR_factor_ref         0.0780
_reflns_number_gt                4098
_reflns_number_total             4614
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2ob26877a.txt
_cod_data_source_block           iPG4Ca
_cod_original_sg_symbol_H-M      P21/n
_cod_original_formula_sum        'C16 H22 Ca0.50 Cl N10 O2'
_cod_database_code               7152780