Synthesis and crystal structures of novel 1-aza-2-silacyclobut-3-enes
Bowen, Richard J.; Fernandes, Manuel A.; Hitchcock, Peter B.; Lappert, Michael F.; Layh, Marcus; Journal of the Chemical Society, Dalton Transactions  (2002) 3253–; doi:10.1039/b202629p

data_7011655
_publ_section_title
;
 Synthesis and crystal structures of novel 1-aza-2-silacyclobut-3-enes
;
_journal_issue                   16
_journal_name_full
'Journal of the Chemical Society, Dalton Transactions'
_journal_page_first              3253
_journal_paper_doi               10.1039/b202629p
_journal_year                    2002
_chemical_formula_moiety         'C33 H61 Li N4 Si4'
_chemical_formula_sum            'C33 H61 Li N4 Si4'
_chemical_formula_weight         633.16
_chemical_name_systematic
;
(N,N,N',N'-Tetramethylethylenediamine)-(1-(2,6-dimethylphenyl)-
2,2-bis(trimethylsilyl)-3-(trimethylsilyl-4-(2,6-dimethylphenyl)amido-
1-aza-2-sila-cyclobut-3-ene-N)-lithium
;
_chemical_temperature_decomposition 397.15
_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           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 105.285(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   17.600(3)
_cell_length_b                   18.995(4)
_cell_length_c                   24.897(4)
_cell_measurement_temperature    173(2)
_cell_volume                     8029(3)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.993
_diffrn_measured_fraction_theta_max 0.993
_diffrn_measurement_device_type  '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
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0303
_diffrn_reflns_av_sigmaI/netI    0.0421
_diffrn_reflns_limit_h_max       22
_diffrn_reflns_limit_h_min       -23
_diffrn_reflns_limit_k_max       24
_diffrn_reflns_limit_k_min       -25
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -33
_diffrn_reflns_number            55808
_diffrn_reflns_theta_full        28.31
_diffrn_reflns_theta_max         28.31
_diffrn_reflns_theta_min         1.20
_exptl_absorpt_coefficient_mu    0.173
_exptl_absorpt_correction_T_max  0.9371
_exptl_absorpt_correction_T_min  0.9215
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details
;
SADABS: Area-Detector Absorption 
Correction. (1996)  Siemens Industrial Automation, Inc.: 
Madison, WI.. 
;
_exptl_crystal_colour            'brown light'
_exptl_crystal_density_diffrn    1.048
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       spherical
_exptl_crystal_F_000             2768
_exptl_crystal_preparation       'grown from hexane at -20 C'
_exptl_crystal_size_max          0.48
_exptl_crystal_size_mid          0.38
_exptl_crystal_size_min          0.38
_refine_diff_density_max         0.596
_refine_diff_density_min         -0.344
_refine_diff_density_rms         0.045
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.052
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     791
_refine_ls_number_reflns         19843
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.052
_refine_ls_R_factor_all          0.0836
_refine_ls_R_factor_gt           0.0449
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0643P)^2^+0.9845P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1165
_refine_ls_wR_factor_ref         0.1347
_reflns_number_gt                12833
_reflns_number_total             19843
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b202629p.txt
_cod_data_source_block           d:\wits\marcus\li4rt\work\soln\li4rt_s
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to '/home/adriana/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from
2010-06-29.

'_exptl_absorpt_correction_type' value 'Empirical' changed to
'empirical' according to
'/home/adriana/struct/CIF-dictionaries/cif_core.dic' dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1555 2011-01-17 13:19:09Z saulius 

The following automatic conversions were performed:

'_chemical_melting_point' tag was changed to
'_chemical_temperature_decomposition' since the value had been given
as '124 C (dec.)'. The value '124 C (dec.)' was changed to '397.15' -
it was converted from degrees Celsius(C) to Kelvins(K).

Automatic conversion script
Id: cif_fix_values 1569 2011-02-09 13:29:24Z adriana 
;
_cod_original_sg_symbol_H-M      P21/c
_cod_database_code               7011655