Alkaline earth metal complexes of a chiral polyether as initiator for the ring-opening polymerization of lactide.
Davin, Julien P.; Buffet, Jean-Charles; Spaniol, Thomas P.; Okuda, Jun; Dalton transactions (Cambridge, England : 2003) 41 (2012) 12612–12618; doi:10.1039/c2dt31309j

data_7030299
_publ_section_title
;
 Alkaline earth metal complexes of a chiral polyether as initiator for the
 ring-opening polymerization of lactide.
;
_journal_issue                   40
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              12612
_journal_page_last               12618
_journal_paper_doi               10.1039/c2dt31309j
_journal_volume                  41
_journal_year                    2012
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C20 H52 Ca N2 O4 Si4'
_chemical_formula_sum            'C20 H52 Ca N2 O4 Si4'
_chemical_formula_weight         537.08
_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                   9.321(2)
_cell_length_b                   16.216(4)
_cell_length_c                   21.088(5)
_cell_measurement_reflns_used    6733
_cell_measurement_temperature    130(2)
_cell_measurement_theta_max      24.83
_cell_measurement_theta_min      2.30
_cell_volume                     3187.4(13)
_computing_cell_refinement       'Bruker SMART (2001)'
_computing_data_collection       'Bruker SMART (2001)'
_computing_data_reduction        'Bruker SAINT+ (1999)'
_computing_molecular_graphics    'Ortep-3 for Windows (Farrugia, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SIR 92 (Altomare et al, 1992)'
_diffrn_ambient_temperature      130(2)
_diffrn_measured_fraction_theta_full 0.990
_diffrn_measured_fraction_theta_max 0.990
_diffrn_measurement_device_type  'CCD area detector'
_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  0.1201
_diffrn_reflns_av_sigmaI/netI    0.1477
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            40012
_diffrn_reflns_theta_full        28.49
_diffrn_reflns_theta_max         28.49
_diffrn_reflns_theta_min         1.58
_exptl_absorpt_coefficient_mu    0.372
_exptl_absorpt_correction_T_max  0.9926
_exptl_absorpt_correction_T_min  0.9533
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Bruker SADABS'
_exptl_crystal_density_diffrn    1.119
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             1176
_exptl_crystal_size_max          0.13
_exptl_crystal_size_mid          0.08
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.814
_refine_diff_density_min         -0.551
_refine_diff_density_rms         0.106
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.09(8)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.097
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     331
_refine_ls_number_reflns         7992
_refine_ls_number_restraints     24
_refine_ls_restrained_S_all      1.095
_refine_ls_R_factor_all          0.1149
_refine_ls_R_factor_gt           0.0907
_refine_ls_shift/su_max          0.006
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0757P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2087
_refine_ls_wR_factor_ref         0.2200
_reflns_number_gt                5690
_reflns_number_total             7992
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2dt31309j.txt
_cod_data_source_block           rac9
_cod_database_code               7030299