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_7152778
_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_sum            'C8.5 H11.5 Cl1.5 N5 O'
_chemical_formula_weight         252.90
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_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            16
_cell_length_a                   15.6275(12)
_cell_length_b                   14.9143(11)
_cell_length_c                   20.2340(15)
_cell_measurement_temperature    120(2)
_cell_volume                     4716.0(6)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      120(2)
_diffrn_measured_fraction_theta_full 0.992
_diffrn_measured_fraction_theta_max 0.992
_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  0.0165
_diffrn_reflns_av_sigmaI/netI    0.0117
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       26
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            25346
_diffrn_reflns_theta_full        27.56
_diffrn_reflns_theta_max         27.56
_diffrn_reflns_theta_min         2.01
_exptl_absorpt_coefficient_mu    0.425
_exptl_absorpt_correction_T_max  0.9587
_exptl_absorpt_correction_T_min  0.9587
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS V2008/1 (Bruker AXS)'
_exptl_crystal_colour            noncolor
_exptl_crystal_density_diffrn    1.425
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             2096
_exptl_crystal_size_max          0.10
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.856
_refine_diff_density_min         -0.672
_refine_diff_density_rms         0.054
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.030
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     293
_refine_ls_number_reflns         5420
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.030
_refine_ls_R_factor_all          0.0380
_refine_ls_R_factor_gt           0.0353
_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^)+(0.0474P)^2^+3.9739P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0941
_refine_ls_wR_factor_ref         0.0967
_reflns_number_gt                4991
_reflns_number_total             5420
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2ob26877a.txt
_cod_data_source_block           iPG_R
_cod_original_sg_symbol_H-M      Pbca
_cod_database_code               7152778