Cyclo(<small>L</small>-isoleucyl-<small>L</small>-isoleucyl)
Görbitz, Carl Henrik; Hartviksen, Lars Male; Acta Crystallographica Section E 62 (2006) o2358–o2360; doi:10.1107/S1600536806017338

data_2209254
_publ_section_title
;
 Cyclo(<small>L</small>-isoleucyl-<small>L</small>-isoleucyl)
;
_journal_coeditor_code           LH2073
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o2358
_journal_page_last               o2360
_journal_paper_doi               10.1107/S1600536806017338
_journal_volume                  62
_journal_year                    2006
_chemical_formula_iupac          'C12 H22 N2 O2'
_chemical_formula_moiety         'C12 H22 N2 O2'
_chemical_formula_sum            'C12 H22 N2 O2'
_chemical_formula_weight         226.32
_chemical_name_common            cyclo(L-isoleucyl-L-isoleucyl)
_chemical_name_systematic
;
(3S,6S)-3,6-bis(S-sec-butyl)-2,5-piperazine-2,5-dione
;
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 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            4
_cell_length_a                   6.242(9)
_cell_length_b                   10.814(15)
_cell_length_c                   19.79(3)
_cell_measurement_reflns_used    4248
_cell_measurement_temperature    105(2)
_cell_measurement_theta_max      28.18
_cell_measurement_theta_min      2.06
_cell_volume                     1336(3)
_computing_cell_refinement       'SAINT-Plus (Bruker, 2001)'
_computing_data_collection       'SMART (Bruker, 1998)'
_computing_data_reduction        SAINT
_computing_molecular_graphics    SHELXTL
_computing_publication_material  SHELXTL
_computing_structure_refinement  SHELXTL
_computing_structure_solution    'SHELXTL (Bruker, 2000)'
_diffrn_ambient_temperature      105(2)
_diffrn_detector_area_resol_mean 8.3
_diffrn_measured_fraction_theta_full 0.976
_diffrn_measured_fraction_theta_max 0.912
_diffrn_measurement_device_type  'Siemens SMART CCD'
_diffrn_measurement_method
'Sets of exposures each taken over 0.3\% \w rotation'
_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  0.0403
_diffrn_reflns_av_sigmaI/netI    0.0371
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            7470
_diffrn_reflns_theta_full        25.03
_diffrn_reflns_theta_max         28.18
_diffrn_reflns_theta_min         2.06
_diffrn_standards_decay_%        0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.077
_exptl_absorpt_correction_T_max  0.9939
_exptl_absorpt_correction_T_min  0.7664
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.125
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             496
_exptl_crystal_size_max          1.30
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.298
_refine_diff_density_min         -0.187
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.087
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     156
_refine_ls_number_reflns         1739
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.087
_refine_ls_R_factor_all          0.0431
_refine_ls_R_factor_gt           0.0361
_refine_ls_shift/su_max          0.006
_refine_ls_shift/su_mean         0.002
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0514P)^2^+0.2942P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0934
_refine_ls_wR_factor_ref         0.1057
_reflns_number_gt                1557
_reflns_number_total             1739
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            lh2073.cif
_cod_data_source_block           I
_cod_database_code               2209254