Highly heteroselective ring-opening polymerization of racemic lactide initiated by bis(phenolate) divalent ytterbium complexes
Sheng Yang; Zhu Du; Yong Zhang; Qi Shen; Chem.Commun. 48 (2012) 9780–; doi:10.1039/c2cc34451c

data_7108369
_publ_section_title
;
 Highly heteroselective ring-opening polymerization of racemic lactide
 initiated by bis(phenolate) divalent ytterbium complexes
;
_journal_name_full               Chem.Commun.
_journal_page_first              9780
_journal_paper_doi               10.1039/c2cc34451c
_journal_volume                  48
_journal_year                    2012
_chemical_formula_moiety         'C18 H52 N4 Si4 Yb'
_chemical_formula_sum            'C18 H52 N4 Si4 Yb'
_chemical_formula_weight         610.04
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      15
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 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                 102.324(8)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   8.649(3)
_cell_length_b                   17.753(5)
_cell_length_c                   20.315(7)
_cell_measurement_reflns_used    7147
_cell_measurement_temperature    223(2)
_cell_measurement_theta_max      27.6
_cell_measurement_theta_min      3.0
_cell_volume                     3047.4(17)
_computing_cell_refinement       CrystalClear
_computing_data_collection       CrystalClear
_computing_data_reduction        CrystalStructure
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      223(2)
_diffrn_detector_area_resol_mean 14.63
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'Rigaku Saturn'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71075
_diffrn_reflns_av_R_equivalents  0.1302
_diffrn_reflns_av_sigmaI/netI    0.1660
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            7606
_diffrn_reflns_theta_full        25.50
_diffrn_reflns_theta_max         25.50
_diffrn_reflns_theta_min         3.04
_exptl_absorpt_coefficient_mu    3.236
_exptl_absorpt_correction_T_max  0.724
_exptl_absorpt_correction_T_min  0.143
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Jacobson, R. (1998) Private communication'
_exptl_crystal_colour            purple
_exptl_crystal_density_diffrn    1.330
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             1256
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.10
_refine_diff_density_max         3.747
_refine_diff_density_min         -3.628
_refine_diff_density_rms         0.280
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.940
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     132
_refine_ls_number_reflns         2825
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.940
_refine_ls_R_factor_all          0.1067
_refine_ls_R_factor_gt           0.0880
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1039P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2037
_refine_ls_wR_factor_ref         0.2110
_reflns_number_gt                1828
_reflns_number_total             2825
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2cc34451c-1.cif
_cod_data_source_block           compound2
_cod_original_cell_volume        3047.6(16)
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               7108369