From silicon(II)-based dioxygen activation to adducts of elusive dioxasiliranes and sila-ureas stable at room temperature.
Xiong, Yun; Yao, Shenglai; Müller, Robert; Kaupp, Martin; Driess, Matthias; Nature chemistry 2 (2010) 577–580; doi:10.1038/nchem.666

data_1508054
_publ_section_title
;
 From silicon(II)-based dioxygen activation to adducts of elusive
 dioxasiliranes and sila-ureas stable at room temperature.
;
_journal_issue                   7
_journal_name_full               'Nature chemistry'
_journal_page_first              577
_journal_page_last               580
_journal_paper_doi               10.1038/nchem.666
_journal_volume                  2
_journal_year                    2010
_chemical_formula_sum            'C39.5 H56 N4 O2 Si'
_chemical_formula_weight         646.97
_chemical_name_systematic
; 
1,2-dioxa-4,8-diaza-3-sila-spiro[2.5]oct-5-ene,
3-[1,3-dihydro-1,3,4,5-tetramethyl-2H-imidazol-
2-ylidene)]-4,8-Bis-[2,6- bis(1-methylethyl)phenyl]-
5-methyl-7-methylene-
;
_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
;
CrysAlis RED, Oxford Diffraction Ltd.,
Version 1.171.31.8 (release 12-01-2007 CrysAlis171 .NET)
(compiled Jan 12 2007,17:49:11)
;
_cell_angle_alpha                90.00
_cell_angle_beta                 108.997(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   17.0069(5)
_cell_length_b                   13.0836(5)
_cell_length_c                   18.0462(6)
_cell_measurement_reflns_used    5343
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      32.4249
_cell_measurement_theta_min      2.9633
_cell_volume                     3796.8(2)
_computing_cell_refinement
;
CrysAlis RED, Oxford Diffraction Ltd.,
Version 1.171.31.8 (release 12-01-2007 CrysAlis171 .NET)
(compiled Jan 12 2007,17:49:11)
;
_computing_data_collection
;
CrysAlis CCD, Oxford Diffraction Ltd.,
Version 1.171.31.8 (release 12-01-2007 CrysAlis171 .NET)
(compiled Jan 12 2007,17:49:11)
;
_computing_data_reduction
;
CrysAlis RED, Oxford Diffraction Ltd.,
Version 1.171.31.8 (release 12-01-2007 CrysAlis171 .NET)
(compiled Jan 12 2007,17:49:11)
;
_computing_publication_material  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Oxford Diffraction Xcalibur S Sapphire'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'Enhance (Mo) X-ray Source'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0679
_diffrn_reflns_av_sigmaI/netI    0.0934
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -20
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            21357
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         2.97
_exptl_absorpt_coefficient_mu    0.099
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            green
_exptl_crystal_density_diffrn    1.132
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             1404
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.16
_exptl_crystal_size_min          0.12
_refine_diff_density_max         0.293
_refine_diff_density_min         -0.261
_refine_diff_density_rms         0.043
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.014
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     465
_refine_ls_number_reflns         6670
_refine_ls_number_restraints     92
_refine_ls_restrained_S_all      1.036
_refine_ls_R_factor_all          0.1230
_refine_ls_R_factor_gt           0.0615
_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^)+(0.0671P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1243
_refine_ls_wR_factor_ref         0.1435
_reflns_number_gt                3964
_reflns_number_total             6670
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            nchem.666-s3.cif
_cod_data_source_block           2b
_cod_original_sg_symbol_H-M      P21/n
_cod_original_formula_sum        'C39.50 H56 N4 O2 Si'
_cod_database_code               1508054