Sodium and potassium 3-sila-Î²-diketiminates show new coordination modes
Farwell, James D.; Hitchcock, Peter B.; Lappert, Michael F.; Chemical Communications  (2002) 456–; doi:10.1039/b110443h

data_7114350
_publ_section_title
;
 Sodium and potassium 3-sila-\^I&#x00B2;-diketiminates show new
 coordination modes
;
_journal_issue                   5
_journal_name_full               'Chemical Communications'
_journal_page_first              456
_journal_paper_doi               10.1039/b110443h
_journal_year                    2002
_chemical_formula_sum            'C68 H106 N4 Na2 Si8'
_chemical_formula_weight         1250.27
_chemical_name_common
;
[{Na(RNCR"Si(R)CR"NR)}2] R=SiMe3,R"=C6H3Me2
;
_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                 111.69(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   14.372(7)
_cell_length_b                   15.689(4)
_cell_length_c                   18.281(7)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      10
_cell_measurement_theta_min      7
_cell_volume                     3830(3)
_computing_cell_refinement       'Enraf-Nonius CAD4'
_computing_data_collection       'Enraf-Nonius CAD4'
_computing_molecular_graphics    'CAMERON (Watkin and Pearce,1993)'
_computing_publication_material  SHELXL-93
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_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  0.0501
_diffrn_reflns_av_sigmaI/netI    0.1242
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            6998
_diffrn_reflns_theta_full        24.97
_diffrn_reflns_theta_max         24.97
_diffrn_reflns_theta_min         2.00
_diffrn_standards_decay_%        0
_diffrn_standards_interval_time  120
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    0.190
_exptl_absorpt_correction_T_max  1.00
_exptl_absorpt_correction_T_min  0.88
_exptl_absorpt_correction_type   empirical
_exptl_crystal_density_diffrn    1.084
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1352
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.20
_refine_diff_density_max         1.229
_refine_diff_density_min         -0.525
_refine_diff_density_rms         0.073
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.015
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     404
_refine_ls_number_reflns         6721
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.015
_refine_ls_R_factor_all          0.1790
_refine_ls_R_factor_gt           0.0897
_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^)+(0.1094P)^2^+4.7594P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2152
_refine_ls_wR_factor_ref         0.2661
_reflns_number_gt                3389
_reflns_number_total             6721
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b110443h.txt
_cod_data_source_block           mar1299
_cod_original_sg_symbol_H-M      P2(1)/c
_cod_database_code               7114350