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_7011656
_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         'C27 H46 N2 Si4'
_chemical_formula_sum            'C27 H46 N2 Si4'
_chemical_formula_weight         511.02
_chemical_melting_point          190
_chemical_name_systematic
;
1-(2,6-dimethylphenyl)-2,2-bis(trimethylsilyl)-3-(trimethylsilyl-4-
(2,6-dimethylphenyl)amine
;
_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           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 98.05(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.179(2)
_cell_length_b                   20.683(7)
_cell_length_c                   16.748(7)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      10
_cell_measurement_theta_min      7
_cell_volume                     3148.3(18)
_computing_cell_refinement       'Enraf Nonius CAD4'
_computing_data_collection       'Enraf Nonius CAD4'
_computing_molecular_graphics    'Cameron (Watkin and Pearce, 1993)'
_computing_publication_material  SHELXL-97
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-86 (Sheldrick, 1990)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Enraf Nonius CAD4'
_diffrn_measurement_method       \w--2\q
_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  0.0219
_diffrn_reflns_av_sigmaI/netI    0.0648
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       27
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            8019
_diffrn_reflns_theta_full        27.99
_diffrn_reflns_theta_max         27.99
_diffrn_reflns_theta_min         2.32
_diffrn_standards_decay_%        0
_diffrn_standards_interval_time  120
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    0.206
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.078
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             1112
_exptl_crystal_preparation       'grown from pentane at -20 C'
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.40
_exptl_crystal_size_min          0.40
_refine_diff_density_max         0.402
_refine_diff_density_min         -0.433
_refine_diff_density_rms         0.054
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.023
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     315
_refine_ls_number_reflns         7577
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.023
_refine_ls_R_factor_all          0.0905
_refine_ls_R_factor_gt           0.0549
_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^)+(0.0483P)^2^+1.7786P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1220
_refine_ls_wR_factor_ref         0.1395
_reflns_number_gt                5222
_reflns_number_total             7577
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b202629p.txt
_cod_data_source_block           f:\marcus\updates\sep988
_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.

Automatic conversion script
Id: cif_fix_enum 1555 2011-01-17 13:19:09Z saulius 
;
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               7011656