(5<i>R</i>)-5,9,9-Trimethyl-5,6,7,8-tetrahydro-5,8-methanoquinoxaline: a chiral Mills–Nixon pyrazine
Fitchett, Christopher M.; Steel, Peter J.; Acta Crystallographica Section E 63 (2007) o4899–o4899; doi:10.1107/S1600536807060710

data_2216648
_publ_section_title
;
 (5<i>R</i>)-5,9,9-Trimethyl-5,6,7,8-tetrahydro-5,8-methanoquinoxaline:
 a chiral Mills--Nixon pyrazine
;
_journal_coeditor_code           LW2042
_journal_issue                   12
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o4899
_journal_page_last               o4899
_journal_paper_doi               10.1107/S1600536807060710
_journal_volume                  63
_journal_year                    2007
_chemical_formula_iupac          'C12 H16 N2'
_chemical_formula_moiety         'C12 H16 N2'
_chemical_formula_sum            'C12 H16 N2'
_chemical_formula_weight         188.27
_chemical_name_systematic
;
(5R)-5,9,9-Trimethyl-5,6,7,8-tetrahydro-5,8-methanoquinoxaline
;
_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                   6.7201(16)
_cell_length_b                   12.069(3)
_cell_length_c                   12.880(3)
_cell_measurement_reflns_used    7694
_cell_measurement_temperature    168(2)
_cell_measurement_theta_max      26.30
_cell_measurement_theta_min      2.31
_cell_volume                     1044.6(4)
_computing_cell_refinement       'SAINT (Bruker 1997)'
_computing_data_collection       'SMART (Bruker 1997)'
_computing_data_reduction        'SAINT (Bruker 1997)'
_computing_molecular_graphics    'SHELXTL, (Bruker 1997)'
_computing_publication_material  'SHELXTL (Bruker 1997)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      168(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'Bruker SMART 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  0.0250
_diffrn_reflns_av_sigmaI/netI    0.0131
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            10747
_diffrn_reflns_theta_full        26.30
_diffrn_reflns_theta_max         26.30
_diffrn_reflns_theta_min         2.31
_exptl_absorpt_coefficient_mu    0.072
_exptl_absorpt_correction_T_max  0.9726
_exptl_absorpt_correction_T_min  0.9021
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 2002)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.197
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             408
_exptl_crystal_size_max          0.49
_exptl_crystal_size_mid          0.48
_exptl_crystal_size_min          0.39
_refine_diff_density_max         0.143
_refine_diff_density_min         -0.251
_refine_ls_abs_structure_details 'Friedel pairs merged'
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.125
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     128
_refine_ls_number_reflns         1245
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.125
_refine_ls_R_factor_all          0.0370
_refine_ls_R_factor_gt           0.0345
_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^)+(0.0583P)^2^+0.1417P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0902
_refine_ls_wR_factor_ref         0.0924
_reflns_number_gt                1182
_reflns_number_total             1245
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            lw2042.cif
_cod_data_source_block           I
_cod_database_code               2216648
_cod_database_fobs_code          2216648