Bridged tolanes: a twisted tale.
Menning, Sebastian; Krämer, Maximilian; Duckworth, Andrew; Rominger, Frank; Beeby, Andrew; Dreuw, Andreas; Bunz, Uwe H. F.; The Journal of organic chemistry 79 (2014) 6571–6578; doi:10.1021/jo5010235

data_4029646
_publ_section_title
;
 Bridged tolanes: a twisted tale.
;
_journal_issue                   14
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              6571
_journal_page_last               6578
_journal_paper_doi               10.1021/jo5010235
_journal_volume                  79
_journal_year                    2014
_chemical_formula_sum            'C20 H14 O4'
_chemical_formula_weight         318.31
_chemical_name_systematic
; 
 ? 
;
_space_group_crystal_system      monoclinic
_space_group_IT_number           15
_space_group_name_Hall           '-C 2yc'
_space_group_name_H-M_alt        'C 1 2/c 1'
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014
_cell_angle_alpha                90
_cell_angle_beta                 104.768(5)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   31.285(5)
_cell_length_b                   12.3872(19)
_cell_length_c                   9.6298(17)
_cell_measurement_reflns_used    2761
_cell_measurement_temperature    200(2)
_cell_measurement_theta_max      21.09
_cell_measurement_theta_min      2.60
_cell_volume                     3608.6(10)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2014 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      200(2)
_diffrn_measured_fraction_theta_full 0.742
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker APEX-II Quazar'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0874
_diffrn_reflns_av_unetI/netI     0.0651
_diffrn_reflns_Laue_measured_fraction_full 0.742
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       33
_diffrn_reflns_limit_h_min       -33
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -10
_diffrn_reflns_number            15063
_diffrn_reflns_point_group_measured_fraction_full 0.742
_diffrn_reflns_point_group_measured_fraction_max 1.000
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         22.720
_diffrn_reflns_theta_min         1.346
_exptl_absorpt_coefficient_mu    0.082
_exptl_absorpt_correction_T_max  0.9579
_exptl_absorpt_correction_T_min  0.6515
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.172
_exptl_crystal_description       needle
_exptl_crystal_F_000             1328
_exptl_crystal_size_max          0.450
_exptl_crystal_size_mid          0.050
_exptl_crystal_size_min          0.040
_refine_diff_density_max         0.195
_refine_diff_density_min         -0.202
_refine_diff_density_rms         0.042
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.039
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     217
_refine_ls_number_reflns         2428
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.039
_refine_ls_R_factor_all          0.0862
_refine_ls_R_factor_gt           0.0541
_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^)+(0.0542P)^2^+4.7166P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1280
_refine_ls_wR_factor_ref         0.1423
_reflns_Friedel_coverage         0.000
_reflns_number_gt                1630
_reflns_number_total             2428
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo5010235_si_010.cif
_cod_data_source_block           sme29_sq
_cod_depositor_comments
'Adding full bibliography for 4029638--4029646.cif.'
_cod_database_code               4029646
_shelx_estimated_absorpt_t_min   0.964
_shelx_estimated_absorpt_t_max   0.997
_shelxl_version_number           2014-3
_shelx_res_checksum              31447
_shelx_hkl_checksum              7002
_shelx_fab_checksum              9686