2,2,7,7-Tetramethyl-2,3,6,7-tetrahydrobenzofuro[7,6-<i>b</i>]furan
Luo, Xian-Fu; Yang, Lin-Tao; Wang, Yu; Zhang, Jian-Yu; Hu, Ai-Xi; Acta Crystallographica Section E 66 (2010) o567–; doi:10.1107/S1600536810004423

data_2225175
_publ_section_title
;
 2,2,7,7-Tetramethyl-2,3,6,7-tetrahydrobenzofuro[7,6-<i>b</i>]furan
;
_journal_issue                   3
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o567
_journal_paper_doi               10.1107/S1600536810004423
_journal_volume                  66
_journal_year                    2010
_chemical_formula_iupac          'C14 H18 O2'
_chemical_formula_moiety         'C14 H18 O2'
_chemical_formula_sum            'C14 H18 O2'
_chemical_formula_weight         218.28
_chemical_melting_point          344.25
_chemical_name_systematic
;
2,2,7,7-Tetramethyl-2,3,6,7-tetrahydrobenzofuro[7,6-<i>b</i>]furan
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_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                 92.1860(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   8.7553(6)
_cell_length_b                   6.0721(4)
_cell_length_c                   23.2082(17)
_cell_measurement_reflns_used    2852
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      26.98
_cell_measurement_theta_min      2.46
_cell_volume                     1232.92(15)
_computing_cell_refinement       'SAINT-PLUS (Bruker, 2003)'
_computing_data_collection       'SMART (Bruker, 2001)'
_computing_data_reduction        'SAINT-PLUS (Bruker, 2003)'
_computing_molecular_graphics    'SHELXTL (Sheldrick 2008)'
_computing_publication_material  'SHELXTL (Sheldrick 2008)'
_computing_structure_refinement  'SHELXTL (Sheldrick 2008)'
_computing_structure_solution    'SHELXTL (Sheldrick 2008)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.987
_diffrn_measured_fraction_theta_max 0.987
_diffrn_measurement_device_type  'Bruker SMART 1000 CCD diffractometer'
_diffrn_measurement_method       '\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  0.0218
_diffrn_reflns_av_sigmaI/netI    0.0303
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            5882
_diffrn_reflns_theta_full        27.04
_diffrn_reflns_theta_max         27.04
_diffrn_reflns_theta_min         1.76
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.077
_exptl_absorpt_correction_T_max  0.9706
_exptl_absorpt_correction_T_min  0.9662
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 2004)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.176
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             472
_exptl_crystal_size_max          0.45
_exptl_crystal_size_mid          0.44
_exptl_crystal_size_min          0.39
_refine_diff_density_max         0.254
_refine_diff_density_min         -0.175
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.043
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     149
_refine_ls_number_reflns         2662
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.043
_refine_ls_R_factor_all          0.0610
_refine_ls_R_factor_gt           0.0448
_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^)+(0.0698P)^2^+0.2701P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1198
_refine_ls_wR_factor_ref         0.1313
_reflns_number_gt                1986
_reflns_number_total             2662
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            bt5185.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'P 21/n'
_cod_database_code               2225175
_cod_database_fobs_code          2225175