Twisted oxygen-containing oligosilanes–unprecedented examples of sigma-n mixed conjugated systems.
Krempner, Clemens; Ludwig, Ralf; Flemming, Anke; Miethchen, Ralf; Köckerling, Martin; Chemical communications (Cambridge, England)  (2007) 1810–1812; doi:10.1039/b618438c

data_7101881
_publ_section_title
;
 Twisted oxygen-containing oligosilanes--unprecedented examples of
 sigma-n mixed conjugated systems.
;
_journal_issue                   18
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              1810
_journal_page_last               1812
_journal_paper_doi               10.1039/b618438c
_journal_year                    2007
_chemical_formula_moiety         'C20 H52 O2 Si7'
_chemical_formula_sum            'C20 H52 O2 Si7'
_chemical_formula_weight         521.25
_chemical_melting_point          421
_chemical_name_systematic
;
4,4-Dimethyl-(1 RS, 7 SR)-2,6-Dioxa-3,3,5,5-tetrakis
(trimethylsilyl)-3,4,5-trisila-cis-bicyclo[5.3.1]undecane
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           'ct.exe (M. K\"ockerling, 1996)'
_cell_angle_alpha                90.00
_cell_angle_beta                 107.816(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.0842(9)
_cell_length_b                   30.120(3)
_cell_length_c                   10.5929(9)
_cell_measurement_reflns_used    8463
_cell_measurement_temperature    243(2)
_cell_measurement_theta_max      29.71
_cell_measurement_theta_min      2.35
_cell_volume                     3366.9(5)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'Bruker SHELXTL'
_computing_structure_solution    'Bruker SHELXTL'
_diffrn_ambient_temperature      243(2)
_diffrn_measured_fraction_theta_full 0.900
_diffrn_measured_fraction_theta_max 0.900
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0339
_diffrn_reflns_av_sigmaI/netI    0.0250
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_k_max       36
_diffrn_reflns_limit_k_min       -43
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            87851
_diffrn_reflns_theta_full        32.35
_diffrn_reflns_theta_max         32.35
_diffrn_reflns_theta_min         2.36
_exptl_absorpt_coefficient_mu    0.297
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.8949
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.028
_exptl_crystal_description       block
_exptl_crystal_F_000             1144
_exptl_crystal_size_max          0.80
_exptl_crystal_size_mid          0.80
_exptl_crystal_size_min          0.50
_refine_diff_density_max         0.825
_refine_diff_density_min         -0.378
_refine_diff_density_rms         0.054
_refine_ls_goodness_of_fit_ref   1.041
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     317
_refine_ls_number_reflns         10829
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.041
_refine_ls_R_factor_all          0.0815
_refine_ls_R_factor_gt           0.0574
_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^)+(0.0597P)^2^+2.0160P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1432
_refine_ls_wR_factor_ref         0.1557
_reflns_number_gt                7773
_reflns_number_total             10829
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b618438c.txt
_cod_data_source_block           AF2a_1
_cod_database_code               7101881