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_7042878
_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         'C24 H68 K2 N6 Si4'
_chemical_formula_sum            'C24 H68 K2 N6 Si4'
_chemical_formula_weight         631.40
_chemical_name_systematic
;
 ?
;
_chemical_properties_physical
', Air-sensitive,Moisture-sensitive,Oxygen-sensitive'
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   mixed
_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                 91.606(2)
_cell_angle_gamma                90
_cell_formula_units_Z            12
_cell_length_a                   25.0098(6)
_cell_length_b                   41.6744(9)
_cell_length_c                   11.7634(3)
_cell_measurement_reflns_used    28658
_cell_measurement_temperature    123(2)
_cell_measurement_theta_max      28.4005
_cell_measurement_theta_min      3.0856
_cell_volume                     12255.8(5)
_computing_cell_refinement
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET)
(compiled Jan  5 2010,16:28:46)
;
_computing_data_collection
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET)
(compiled Jan  5 2010,16:28:46)
;
_computing_data_reduction
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET)
(compiled Jan  5 2010,16:28:46)
;
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_diffrn_ambient_temperature      123(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Oxford Diffraction Xcalibur E'
_diffrn_measurement_method       'omega scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0249
_diffrn_reflns_av_unetI/netI     0.0711
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       31
_diffrn_reflns_limit_h_min       -31
_diffrn_reflns_limit_k_max       53
_diffrn_reflns_limit_k_min       -52
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            68311
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.000
_diffrn_reflns_theta_min         3.092
_diffrn_source                   'sealed tube'
_exptl_absorpt_coefficient_mu    0.370
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.81181
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET)
(compiled Jan  5 2010,16:28:46)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.027
_exptl_crystal_description       block
_exptl_crystal_F_000             4176
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.14
_exptl_crystal_size_min          0.06
_refine_diff_density_max         0.613
_refine_diff_density_min         -0.355
_refine_diff_density_rms         0.055
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.949
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     1121
_refine_ls_number_reflns         26683
_refine_ls_number_restraints     439
_refine_ls_restrained_S_all      0.950
_refine_ls_R_factor_all          0.0891
_refine_ls_R_factor_gt           0.0485
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0560P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1053
_refine_ls_wR_factor_ref         0.1135
_reflns_Friedel_coverage         0.000
_reflns_number_gt                16447
_reflns_number_total             26683
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c7dt01118k2.cif
_cod_data_source_block           srgr1001_anto
_cod_database_code               7042878
_shelxl_version_number           2013-4
_shelx_res_checksum              50823