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_7042877
_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         'C22 H58 K N5 O2 Si2'
_chemical_formula_sum            'C22 H58 K N5 O2 Si2'
_chemical_formula_weight         520.01
_chemical_properties_physical
', Air-sensitive,Moisture-sensitive,Oxygen-sensitive'
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yab'
_space_group_name_H-M_alt        'P 1 21/a 1'
_symmetry_space_group_name_Hall  '-P 2yab'
_symmetry_space_group_name_H-M   'P 1 21/a 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2013
_audit_update_record
;
2017-03-14 deposited with the CCDC.
2017-04-17 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90.091(2)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   22.8421(6)
_cell_length_b                   16.2474(4)
_cell_length_c                   17.8186(6)
_cell_measurement_reflns_used    15864
_cell_measurement_temperature    123(2)
_cell_measurement_theta_max      72.9880
_cell_measurement_theta_min      3.3150
_cell_volume                     6612.9(3)
_computing_cell_refinement
;
CrysAlisPro, Agilent Technologies,
Version 1.171.37.34 (release 22-05-2014 CrysAlis171 .NET)
(compiled May 22 2014,16:03:01)
;
_computing_data_collection
;
CrysAlisPro, Agilent Technologies,
Version 1.171.37.34 (release 22-05-2014 CrysAlis171 .NET)
(compiled May 22 2014,16:03:01)
;
_computing_data_reduction
;
CrysAlisPro, Agilent Technologies,
Version 1.171.37.34 (release 22-05-2014 CrysAlis171 .NET)
(compiled May 22 2014,16:03:01)
;
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_diffrn_ambient_temperature      123(2)
_diffrn_measured_fraction_theta_full 1.001
_diffrn_measured_fraction_theta_max 0.988
_diffrn_measurement_device_type  'Oxford Diffraction Gemini S'
_diffrn_measurement_method       'omega scans'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.5418
_diffrn_reflns_av_R_equivalents  0.0609
_diffrn_reflns_av_unetI/netI     0.0538
_diffrn_reflns_Laue_measured_fraction_full 1.001
_diffrn_reflns_Laue_measured_fraction_max 0.988
_diffrn_reflns_limit_h_max       21
_diffrn_reflns_limit_h_min       -27
_diffrn_reflns_limit_k_max       19
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            52705
_diffrn_reflns_point_group_measured_fraction_full 1.001
_diffrn_reflns_point_group_measured_fraction_max 0.988
_diffrn_reflns_theta_full        70.000
_diffrn_reflns_theta_max         73.360
_diffrn_reflns_theta_min         3.148
_diffrn_source                   'sealed tube'
_exptl_absorpt_coefficient_mu    2.278
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.52884
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro, Agilent Technologies,
Version 1.171.37.34 (release 22-05-2014 CrysAlis171 .NET)
(compiled May 22 2014,16:03:01)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.045
_exptl_crystal_description       block
_exptl_crystal_F_000             2304
_exptl_crystal_size_max          0.26
_exptl_crystal_size_mid          0.24
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.431
_refine_diff_density_min         -0.309
_refine_diff_density_rms         0.049
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.054
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     690
_refine_ls_number_reflns         12697
_refine_ls_number_restraints     174
_refine_ls_restrained_S_all      1.051
_refine_ls_R_factor_all          0.0644
_refine_ls_R_factor_gt           0.0505
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0641P)^2^+1.2808P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1338
_refine_ls_wR_factor_ref         0.1457
_reflns_Friedel_coverage         0.000
_reflns_number_gt                10533
_reflns_number_total             12697
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c7dt01118k2.cif
_cod_data_source_block           amao126
_cod_database_code               7042877
_shelxl_version_number           2013-4
_shelx_res_checksum              89752