Exploring the solid state and solution structural chemistry of the utility amide potassium hexamethyldisilazide (KHMDS)
Ojeda-Amador, Ana I.; Martínez-Martínez, Antonio J.; Robertson, Gemma M.; Robertson, Stuart D.; Kennedy, Alan R.; O'Hara, Charles T.; Dalton Trans.  (2017) –; doi:10.1039/C7DT01118K

data_7042885
_publ_section_title
;
 Exploring the solid state and solution structural chemistry of the
 utility amide potassium hexamethyldisilazide (KHMDS)
;
_journal_name_full               'Dalton Trans.'
_journal_paper_doi               10.1039/C7DT01118K
_journal_year                    2017
_chemical_formula_moiety         'C28 H68 K2 N2 O8 Si4, C7 H8'
_chemical_formula_sum            'C35 H76 K2 N2 O8 Si4'
_chemical_formula_weight         843.54
_chemical_properties_physical
', Air-sensitive,Moisture-sensitive,Oxygen-sensitive'
_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
_audit_update_record
;
2017-03-14 deposited with the CCDC.
2017-04-17 downloaded from the CCDC.
;
_cell_angle_alpha                90.00
_cell_angle_beta                 107.587(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   12.4604(4)
_cell_length_b                   12.4931(3)
_cell_length_c                   16.0780(5)
_cell_measurement_reflns_used    6817
_cell_measurement_temperature    123(2)
_cell_measurement_theta_max      29.3549
_cell_measurement_theta_min      2.9510
_cell_volume                     2385.86(13)
_computing_cell_refinement
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.34.40 (release 27-08-2010 CrysAlis171 .NET)
(compiled Aug 27 2010,11:50:40)
;
_computing_data_collection
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.34.40 (release 27-08-2010 CrysAlis171 .NET)
(compiled Aug 27 2010,11:50:40)
;
_computing_data_reduction
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.34.40 (release 27-08-2010 CrysAlis171 .NET)
(compiled Aug 27 2010,11:50:40)
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      123(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.978
_diffrn_measurement_device_type  'Xcalibur, Eos'
_diffrn_measurement_method       '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  0.0298
_diffrn_reflns_av_sigmaI/netI    0.0379
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            17250
_diffrn_reflns_theta_full        27.00
_diffrn_reflns_theta_max         27.99
_diffrn_reflns_theta_min         2.96
_exptl_absorpt_coefficient_mu    0.343
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.92475
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.34.40 (release 27-08-2010 CrysAlis171 .NET)
(compiled Aug 27 2010,11:50:40)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.174
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             916
_exptl_crystal_size_max          0.12
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.465
_refine_diff_density_min         -0.279
_refine_diff_density_rms         0.065
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.215
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     268
_refine_ls_number_reflns         5630
_refine_ls_number_restraints     57
_refine_ls_restrained_S_all      1.221
_refine_ls_R_factor_all          0.0682
_refine_ls_R_factor_gt           0.0522
_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^)+(0.0210P)^2^+3.2975P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1124
_refine_ls_wR_factor_ref         0.1182
_reflns_number_gt                4539
_reflns_number_total             5630
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            c7dt01118k2.cif
_cod_data_source_block           srgr1117
_cod_original_cell_volume        2385.86(12)
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               7042885