Synthesis and application of 3,4,7,8-tetrakis-exo-methylenecycloocta-1,5-diene as a versatile Diels-Alder diene: synthesis of V-shaped cyclooctatetraene fused acenes.
Gadigennavar, Savita; Sankararaman, Sethuraman; Organic & biomolecular chemistry 18 (2020) 6738–6744; doi:10.1039/d0ob01544j

data_7157657
_publ_section_title
;
 Synthesis and application of
 3,4,7,8-tetrakis-exo-methylenecycloocta-1,5-diene as a versatile
 Diels-Alder diene: synthesis of V-shaped cyclooctatetraene fused acenes.
;
_journal_issue                   34
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              6738
_journal_page_last               6744
_journal_paper_doi               10.1039/d0ob01544j
_journal_volume                  18
_journal_year                    2020
_chemical_formula_moiety         'C28 H32 O8'
_chemical_formula_sum            'C28 H32 O8'
_chemical_formula_weight         496.53
_space_group_crystal_system      tetragonal
_space_group_IT_number           82
_space_group_name_Hall           'I -4'
_space_group_name_H-M_alt        'I -4'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2020-07-21 deposited with the CCDC.	2020-08-11 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   31.5358(10)
_cell_length_b                   31.5358(10)
_cell_length_c                   5.2684(2)
_cell_measurement_reflns_used    4535
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      21.58
_cell_measurement_theta_min      2.58
_cell_volume                     5239.5(3)
_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-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick 2008)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.942
_diffrn_measured_fraction_theta_max 0.942
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0424
_diffrn_reflns_av_unetI/netI     0.0628
_diffrn_reflns_Laue_measured_fraction_full 0.942
_diffrn_reflns_Laue_measured_fraction_max 0.942
_diffrn_reflns_limit_h_max       37
_diffrn_reflns_limit_h_min       -36
_diffrn_reflns_limit_k_max       37
_diffrn_reflns_limit_k_min       -37
_diffrn_reflns_limit_l_max       6
_diffrn_reflns_limit_l_min       -5
_diffrn_reflns_number            14835
_diffrn_reflns_point_group_measured_fraction_full 0.934
_diffrn_reflns_point_group_measured_fraction_max 0.934
_diffrn_reflns_theta_full        24.785
_diffrn_reflns_theta_max         24.785
_diffrn_reflns_theta_min         0.913
_exptl_absorpt_coefficient_mu    0.092
_exptl_absorpt_correction_T_max  0.991
_exptl_absorpt_correction_T_min  0.977
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS V2014/5(Bruker AXS.Inc)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.259
_exptl_crystal_description       Rectangular
_exptl_crystal_F_000             2112
_exptl_crystal_size_max          0.250
_exptl_crystal_size_mid          0.220
_exptl_crystal_size_min          0.100
_refine_diff_density_max         0.292
_refine_diff_density_min         -0.162
_refine_diff_density_rms         0.047
_refine_ls_abs_structure_details
; 
 Flack x determined using 806 quotients [(I+)-(I-)]/[(I+)+(I-)] 
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259). 
;
_refine_ls_abs_structure_Flack   0.6(6)
_refine_ls_extinction_coef       0.0013(6)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2014/7 (Sheldrick 2014'
_refine_ls_goodness_of_fit_ref   0.939
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     330
_refine_ls_number_reflns         4221
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.940
_refine_ls_R_factor_all          0.0977
_refine_ls_R_factor_gt           0.0514
_refine_ls_shift/su_max          0.055
_refine_ls_shift/su_mean         0.005
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1025P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1360
_refine_ls_wR_factor_ref         0.1715
_reflns_Friedel_coverage         0.768
_reflns_Friedel_fraction_full    0.924
_reflns_Friedel_fraction_max     0.924
_reflns_number_gt                2393
_reflns_number_total             4221
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d0ob01544j2.cif
_cod_data_source_block           dead
_cod_depositor_comments
'Adding full bibliography for 7157657--7157659.cif.'
_cod_original_cell_volume        5239.5(4)
_cod_database_code               7157657
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.977
_shelx_estimated_absorpt_t_max   0.991
_shelx_res_checksum              16269