Synthesis and structural chemistry of alkali metal tris(HMDS) magnesiates containing chiral diamine donor ligands.
García-Álvarez, Pablo; Kennedy, Alan R.; O'Hara, Charles T; Reilly, Kieran; Robertson, Gemma M.; Dalton transactions (Cambridge, England : 2003) 40 (2011) 5332–5341; doi:10.1039/c1dt10058k

data_7015763
_publ_section_title
;
 Synthesis and structural chemistry of alkali metal tris(HMDS)
 magnesiates containing chiral diamine donor ligands.
;
_journal_issue                   19
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              5332
_journal_page_last               5341
_journal_paper_doi               10.1039/c1dt10058k
_journal_volume                  40
_journal_year                    2011
_chemical_absolute_configuration ad
_chemical_formula_sum            'C48 H106 Li Mg N7 Si6'
_chemical_formula_weight         981.19
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   16.5576(2)
_cell_length_b                   18.5861(3)
_cell_length_c                   19.5813(3)
_cell_measurement_reflns_used    12607
_cell_measurement_temperature    123(2)
_cell_measurement_theta_max      31.1558
_cell_measurement_theta_min      2.4219
_cell_volume                     6025.97(15)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      123(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Oxford Diffraction Gemini S'
_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  0.0472
_diffrn_reflns_av_sigmaI/netI    0.0804
_diffrn_reflns_limit_h_max       18
_diffrn_reflns_limit_h_min       -20
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       -22
_diffrn_reflns_limit_l_max       24
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            35383
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         26.00
_diffrn_reflns_theta_min         3.02
_exptl_absorpt_coefficient_mu    0.185
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.97828
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlis RED, Oxford Diffraction Ltd.,
Version 1.171.32.17 (release 11-02-2008 CrysAlis171 .NET)
(compiled Feb 11 2008,09:33:37)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            COLOURLESS
_exptl_crystal_density_diffrn    1.082
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       FRAGMENT
_exptl_crystal_F_000             2168
_exptl_crystal_size_max          0.16
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.223
_refine_diff_density_min         -0.215
_refine_diff_density_rms         0.037
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.01(6)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.872
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     587
_refine_ls_number_reflns         11806
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.872
_refine_ls_R_factor_all          0.0571
_refine_ls_R_factor_gt           0.0358
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0245P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0558
_refine_ls_wR_factor_ref         0.0587
_reflns_number_gt                8728
_reflns_number_total             11806
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            c1dt10058k.txt
_cod_data_source_block           pgagem11
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'ORTHORHOMBIC' changed to 'orthorhombic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1555 2011-01-17 13:19:09Z saulius 
;
_cod_original_sg_symbol_H-M      P212121
_cod_database_code               7015763