Syntheses and structures of lanthanide borohydrides supported by a bridged bis(amidinate) ligand and their high activity for controlled polymerization of ε-caprolactone, l-lactide and rac-lactide.
Li, Wenbo; Xue, Mingqiang; Tu, Jing; Zhang, Yong; Shen, Qi; Dalton transactions (Cambridge, England : 2003) 41 (2012) 7258–7265; doi:10.1039/c2dt30096f

data_7019251
_publ_section_title
;
 Syntheses and structures of lanthanide borohydrides supported by a
 bridged bis(amidinate) ligand and their high activity for controlled
 polymerization of \e-caprolactone, l-lactide and rac-lactide.
;
_journal_issue                   24
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              7258
_journal_page_last               7265
_journal_paper_doi               10.1039/c2dt30096f
_journal_volume                  41
_journal_year                    2012
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C27 H48 B N4 O2 Si2 Yb, C4 H10 O2'
_chemical_formula_sum            'C31 H58 B N4 O4 Si2 Yb'
_chemical_formula_weight         790.84
_chemical_name_systematic
;
?
;
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_Int_Tables_number      19
_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                   8.6469(12)
_cell_length_b                   19.790(3)
_cell_length_c                   23.214(3)
_cell_measurement_reflns_used    13975
_cell_measurement_temperature    223(2)
_cell_measurement_theta_max      27.5
_cell_measurement_theta_min      3.1
_cell_volume                     3972.4(10)
_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 0.994
_diffrn_measured_fraction_theta_max 0.994
_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  0.0383
_diffrn_reflns_av_sigmaI/netI    0.0998
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -25
_diffrn_reflns_limit_l_max       30
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            16387
_diffrn_reflns_theta_full        27.47
_diffrn_reflns_theta_max         27.47
_diffrn_reflns_theta_min         3.11
_exptl_absorpt_coefficient_mu    2.450
_exptl_absorpt_correction_T_max  0.504
_exptl_absorpt_correction_T_min  0.295
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Jacobson, R. (1998) Private communication'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.322
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1628
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.28
_refine_diff_density_max         0.844
_refine_diff_density_min         -0.855
_refine_diff_density_rms         0.095
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.027(11)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.957
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     369
_refine_ls_number_reflns         8853
_refine_ls_number_restraints     14
_refine_ls_restrained_S_all      0.959
_refine_ls_R_factor_all          0.0521
_refine_ls_R_factor_gt           0.0421
_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^)+(0.0268P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0776
_refine_ls_wR_factor_ref         0.0823
_reflns_number_gt                7566
_reflns_number_total             8853
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2dt30096f.txt
_cod_data_source_block           shelxl4
_cod_database_code               7019251