Heteroscorpionate rare-earth initiators for the controlled ring-opening polymerization of cyclic esters.
Otero, Antonio; Lara-Sánchez, Agustín; Fernández-Baeza, Juan; Alonso-Moreno, Carlos; Márquez-Segovia, Isabel; Sánchez-Barba, Luis F; Castro-Osma, José A; Rodríguez, Ana M; Dalton transactions (Cambridge, England : 2003) 40 (2011) 4687–4696; doi:10.1039/c0dt01678k

data_7015500
_publ_section_title
;
 Heteroscorpionate rare-earth initiators for the controlled
 ring-opening polymerization of cyclic esters.
;
_journal_issue                   17
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              4687
_journal_page_last               4696
_journal_paper_doi               10.1039/c0dt01678k
_journal_volume                  40
_journal_year                    2011
_chemical_formula_moiety         'C40 H74 N12 O2 Si4 Sm2, 4(C7 H8)'
_chemical_formula_sum            'C68 H106 N12 O2 Si4 Sm2'
_chemical_formula_weight         1536.71
_chemical_name_systematic
;
?
;
_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                 94.835(7)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   12.639(6)
_cell_length_b                   26.133(13)
_cell_length_c                   19.332(9)
_cell_measurement_reflns_used    1193
_cell_measurement_temperature    230(2)
_cell_measurement_theta_max      16.702
_cell_measurement_theta_min      2.246
_cell_volume                     6363(5)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX'
_computing_data_reduction        'Bruker SAINT, SADABS, XPREP'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      230(2)
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.985
_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  0.1493
_diffrn_reflns_av_sigmaI/netI    0.2145
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       31
_diffrn_reflns_limit_k_min       -31
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            26689
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         2.25
_exptl_absorpt_coefficient_mu    1.961
_exptl_absorpt_correction_T_max  0.7461
_exptl_absorpt_correction_T_min  0.6318
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.604
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             3176
_exptl_crystal_size_max          0.26
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.16
_refine_diff_density_max         2.710
_refine_diff_density_min         -2.217
_refine_diff_density_rms         0.208
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.936
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     568
_refine_ls_number_reflns         11032
_refine_ls_number_restraints     99
_refine_ls_restrained_S_all      0.985
_refine_ls_R_factor_all          0.1630
_refine_ls_R_factor_gt           0.0888
_refine_ls_shift/su_max          0.031
_refine_ls_shift/su_mean         0.004
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1019P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1973
_refine_ls_wR_factor_ref         0.2311
_reflns_number_gt                4899
_reflns_number_total             11032
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c0dt01678k.txt
_cod_data_source_block           4
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               7015500