A Diels-Alder super diene breaking benzene into C2H2 and C4H4 units.
Inagaki, Yusuke; Nakamoto, Masaaki; Sekiguchi, Akira; Nature communications 5 (2014) 3018–; doi:10.1038/ncomms4018

data_1513796
_publ_section_title
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 A Diels-Alder super diene breaking benzene into C2H2 and C4H4 units.
;
_journal_name_full               'Nature communications'
_journal_page_first              3018
_journal_paper_doi               10.1038/ncomms4018
_journal_volume                  5
_journal_year                    2014
_chemical_formula_sum            'C21 H29 F5 Si3'
_chemical_formula_weight         460.71
_space_group_IT_number           29
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2ac'
_symmetry_space_group_name_H-M   'P c a 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            8
_cell_length_a                   19.1914(10)
_cell_length_b                   10.6017(5)
_cell_length_c                   23.3513(12)
_cell_measurement_reflns_used    9987
_cell_measurement_temperature    120
_cell_measurement_theta_max      27.31
_cell_measurement_theta_min      2.29
_cell_volume                     4751.1(4)
_computing_cell_refinement       'APEX2 (Bruker AXS, 2006)'
_computing_data_collection       'APEX2 (Bruker AXS, 2006)'
_computing_data_reduction        'SAINT (Bruker AXS, 2004)'
_computing_molecular_graphics    'XSHEL (Bruker AXS,2002)'
_computing_publication_material  'XCIF (Bruker AXS, 2001)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      120
_diffrn_detector_area_resol_mean 8.333
_diffrn_measured_fraction_theta_full 0.992
_diffrn_measured_fraction_theta_max 0.992
_diffrn_measurement_device_type  'Bruker APEXII 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
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_diffrn_reflns_av_R_equivalents  0.0251
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_diffrn_reflns_limit_h_min       -23
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       30
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            25588
_diffrn_reflns_theta_full        27.49
_diffrn_reflns_theta_max         27.49
_diffrn_reflns_theta_min         1.74
_exptl_absorpt_coefficient_mu    0.244
_exptl_absorpt_correction_T_max  0.9831
_exptl_absorpt_correction_T_min  0.8899
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details
; 
SADABS Sheldrick 1996 
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.288
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             1936
_exptl_crystal_size_max          0.49
_exptl_crystal_size_mid          0.39
_exptl_crystal_size_min          0.07
_refine_diff_density_max         0.280
_refine_diff_density_min         -0.195
_refine_diff_density_rms         0.038
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.09(5)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.989
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     541
_refine_ls_number_reflns         9902
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.989
_refine_ls_R_factor_all          0.0330
_refine_ls_R_factor_gt           0.0282
_refine_ls_shift/su_max          0.061
_refine_ls_shift/su_mean         0.003
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0298P)^2^+1.0992P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0636
_refine_ls_wR_factor_ref         0.0664
_reflns_number_gt                9121
_reflns_number_total             9902
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ncomms4018-s4.cif
_cod_data_source_block           methylenecyclopropene
_cod_depositor_comments
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The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/usr/data/users/saulius/automatic-downloads/current/Nature/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 2281 2013-09-26 08:29:07Z andrius 

The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'not measured' was changed to '?'
- the value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 
;
_cod_original_sg_symbol_H-M      'Pca2(1) '
_cod_database_code               1513796