Two similar dibenzo cyclic ethers with dissimilar conformations
Burns, Dennis H.; Meece, F. Alex; Moore, Curtis E.; Eichhorn, David M.; Acta Crystallographica Section C 65 (2009) o27–o30; doi:10.1107/S0108270108040882

data_2016933
_publ_section_title
;
 Two similar dibenzo cyclic ethers with dissimilar conformations
;
_journal_coeditor_code           SK3262
_journal_issue                   1
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              o27
_journal_page_last               o30
_journal_paper_doi               10.1107/S0108270108040882
_journal_volume                  65
_journal_year                    2009
_chemical_formula_iupac          'C18 H18 Br2 O2'
_chemical_formula_moiety         'C18 H18 Br2 O2'
_chemical_formula_sum            'C18 H18 Br2 O2'
_chemical_formula_weight         426.14
_chemical_name_common
;
2,12-dibromodibenzo[<i>f</i>,<i>k</i>]-1,5-dioxa-1,2,3,4,5,8,9,10-
octahydrocyclododecene
;
_chemical_name_systematic
;
7,19-dibromo-11,15-dioxatricyclo[14.4.0.0^5,10^]icosaa-5,7,9,16,18,20-hexaene
;
_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           'SHELXL97 (Sheldrick, 2008)'
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   13.7971(5)
_cell_length_b                   8.5744(3)
_cell_length_c                   28.1906(10)
_cell_measurement_reflns_used    5030
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      18.20
_cell_measurement_theta_min      2.95
_cell_volume                     3335.0(2)
_computing_cell_refinement       'APEX2 (Bruker, 2005)'
_computing_data_collection       'APEX2 (Bruker, 2005)'
_computing_data_reduction        'SAINT (Bruker, 1996)'
_computing_molecular_graphics    'SHELXTL (Sheldrick, 2008)'
_computing_publication_material  'SHELXTL (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'CCD area-detector'
_diffrn_measurement_method       '\f and \w 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  0.1559
_diffrn_reflns_av_sigmaI/netI    0.0520
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -17
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       34
_diffrn_reflns_limit_l_min       -34
_diffrn_reflns_number            81249
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         26.00
_diffrn_reflns_theta_min         3.29
_exptl_absorpt_coefficient_mu    4.866
_exptl_absorpt_correction_T_max  0.6070
_exptl_absorpt_correction_T_min  0.3795
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
(SADABS; Sheldrick, 2002)
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.697
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             1696
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.17
_exptl_crystal_size_min          0.11
_refine_diff_density_max         0.324
_refine_diff_density_min         -0.446
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.034
_refine_ls_hydrogen_treatment    noref
_refine_ls_matrix_type           full
_refine_ls_number_parameters     199
_refine_ls_number_reflns         3270
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.034
_refine_ls_R_factor_all          0.0894
_refine_ls_R_factor_gt           0.0396
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0405P)^2^+3.5204P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0800
_refine_ls_wR_factor_ref         0.0997
_reflns_number_gt                2067
_reflns_number_total             3270
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            sk3262.cif
_cod_data_source_block           III
_cod_database_code               2016933
_cod_database_fobs_code          2016933