Why lamivudine assembles into double-stranded helices in crystals: salt heterosynthon versus base-pairing homosynthon
da Silva, Cameron Capeletti; Valdo, Ana K.; do Nascimento Neto, José Antônio; Ribeiro, Leandro; Sarotti, Ariel M.; Martins, Felipe Terra; CrystEngComm 20 (2018) 3049–; doi:10.1039/C8CE00100F

data_7230543
_publ_section_title
;
 Why lamivudine assembles into double-stranded helices in crystals: salt
 heterosynthon versus base-pairing homosynthon
;
_journal_issue                   22
_journal_name_full               CrystEngComm
_journal_page_first              3049
_journal_paper_doi               10.1039/C8CE00100F
_journal_volume                  20
_journal_year                    2018
_chemical_absolute_configuration rmad
_chemical_formula_moiety
'2(C8 H12 N3 O3 S), 2(C8 H11 N3 O3 S), 2(C2 F3 O2), H2 O'
_chemical_formula_sum            'C36 H48 F6 N12 O17 S4'
_chemical_formula_weight         1163.10
_chemical_name_common            'lamivudine duplex V'
_space_group_crystal_system      trigonal
_space_group_IT_number           145
_space_group_name_Hall           'P 32'
_space_group_name_H-M_alt        'P 32'
_symmetry_space_group_name_Hall  'P 32'
_symmetry_space_group_name_H-M   'P 32'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2014
_audit_update_record
;
2017-10-14 deposited with the CCDC.
2018-04-23 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                120
_cell_formula_units_Z            12
_cell_length_a                   29.3603(5)
_cell_length_b                   29.3603(5)
_cell_length_c                   20.4187(4)
_cell_measurement_reflns_used    9947
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      22.88
_cell_measurement_theta_min      2.43
_cell_volume                     15243.3(5)
_computing_structure_refinement  'SHELXL-2014 (Sheldrick, 2014)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0660
_diffrn_reflns_av_unetI/netI     0.0729
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       35
_diffrn_reflns_limit_h_min       -35
_diffrn_reflns_limit_k_max       35
_diffrn_reflns_limit_k_min       -35
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            115389
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.000
_diffrn_reflns_theta_max         25.376
_diffrn_reflns_theta_min         1.387
_exptl_absorpt_coefficient_mu    0.289
_exptl_absorpt_correction_T_max  0.977
_exptl_absorpt_correction_T_min  0.771
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
'Blessing, R. H. (1995) Acta Cryst., A51, 33-38'
_exptl_crystal_density_diffrn    1.520
_exptl_crystal_description       rectangular
_exptl_crystal_F_000             7224
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.661
_refine_diff_density_min         -0.302
_refine_diff_density_rms         0.072
_refine_ls_abs_structure_details
;
 Flack x determined using 6726 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.07(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.025
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     2756
_refine_ls_number_reflns         29358
_refine_ls_number_restraints     2692
_refine_ls_restrained_S_all      1.001
_refine_ls_R_factor_all          0.0922
_refine_ls_R_factor_gt           0.0649
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1197P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1625
_refine_ls_wR_factor_ref         0.1863
_reflns_Friedel_coverage         0.998
_reflns_Friedel_fraction_full    0.998
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                21654
_reflns_number_total             29358
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c8ce00100f2.cif
_cod_data_source_block           shelxl
_cod_depositor_comments
'Adding full bibliography for 7230543--7230547.cif.'
_cod_original_cell_volume        15243.3(7)
_cod_database_code               7230543
_shelxl_version_number           2014-3
_shelx_res_checksum              55907