Potassium‒zinc induced synergic enhancement of the basicity of hexamethyldisilazide (HMDS) towards methylbenzene molecules
Clegg, William; Forbes, Glenn C.; Kennedy, Alan R.; Mulvey, Robert E.; Liddle, Stephen T.; Chemical Communications (Cambridge, United Kingdom)  (2003) 406–407; doi:10.1039/b211392a

data_7113709
_publ_section_title
;
 Potassium--zinc induced synergic enhancement of the basicity of
 hexamethyldisilazide (HMDS) towards methylbenzene molecules
;
_journal_coden_ASTM              CHCOFS
_journal_issue                   3
_journal_name_full
;
 Chemical Communications (Cambridge, United Kingdom)
;
_journal_page_first              406
_journal_page_last               407
_journal_paper_doi               10.1039/b211392a
_journal_year                    2003
_chemical_formula_sum            'C19 H43 K N2 Si4 Zn'
_chemical_formula_weight         516.38
_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                 91.90(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.2390(18)
_cell_length_b                   20.764(4)
_cell_length_c                   15.064(3)
_cell_measurement_reflns_used    77
_cell_measurement_temperature    160(2)
_cell_measurement_theta_max      24.70
_cell_measurement_theta_min      19.95
_cell_volume                     2888.3(10)
_computing_cell_refinement       'Stoe DIF4'
_computing_data_collection       'Stoe DIF4'
_computing_data_reduction        'local programs'
_computing_molecular_graphics    'Siemens SHELXTL'
_computing_publication_material  'SHELXTL and local programs'
_computing_structure_refinement  'Siemens SHELXTL'
_computing_structure_solution    'Siemens SHELXTL'
_diffrn_ambient_temperature      160(2)
_diffrn_measured_fraction_theta_full 0.957
_diffrn_measured_fraction_theta_max 0.957
_diffrn_measurement_device_type  'Stoe-Siemens diffractometer'
_diffrn_measurement_method       '\w/\q scans with on-line profile fitting'
_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  0.2082
_diffrn_reflns_av_sigmaI/netI    0.1549
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       24
_diffrn_reflns_limit_k_min       -24
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            14016
_diffrn_reflns_theta_full        25.21
_diffrn_reflns_theta_max         25.21
_diffrn_reflns_theta_min         1.67
_diffrn_standards_decay_%        7.5
_diffrn_standards_interval_time  60
_diffrn_standards_number         5
_exptl_absorpt_coefficient_mu    1.168
_exptl_absorpt_correction_T_max  0.779
_exptl_absorpt_correction_T_min  0.132
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details   XPREP
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.188
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1104
_exptl_crystal_size_max          0.69
_exptl_crystal_size_mid          0.46
_exptl_crystal_size_min          0.27
_refine_diff_density_max         0.602
_refine_diff_density_min         -0.827
_refine_diff_density_rms         0.094
_refine_ls_extinction_coef       0.0072(8)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.043
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     257
_refine_ls_number_reflns         4975
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.043
_refine_ls_R_factor_all          0.0619
_refine_ls_R_factor_gt           0.0571
_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^)+(0.0126P)^2^+4.7772P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1688
_refine_ls_wR_factor_ref         0.1770
_reflns_number_gt                4438
_reflns_number_total             4975
_reflns_threshold_expression     I>2\s(I)
_cod_duplicate_entry             7103962
_cod_data_source_file            b211392a.txt
_cod_data_source_block           rem285
_cod_original_sg_symbol_H-M      'P 21/n'
_cod_database_code               7113709