Ligand-Free Magnesium Catalyst System: Immortal Polymerization ofl-Lactide with High Catalyst Efficiency and Structure of Active Intermediates
Wang, Yang; Zhao, Wei; Liu, Xinli; Cui, Dongmei; Chen, Eugene Y.-X.; Macromolecules 45 (2012) 6957–; doi:10.1021/ma3007625

data_1508546
_publ_section_title
;
 Ligand-Free Magnesium Catalyst System: Immortal Polymerization
 ofl-Lactide with High Catalyst Efficiency and Structure of Active
 Intermediates
;
_journal_issue                   17
_journal_name_full               Macromolecules
_journal_page_first              6957
_journal_paper_doi               10.1021/ma3007625
_journal_volume                  45
_journal_year                    2012
_chemical_formula_sum            'C28 H25 Mg O2.5'
_chemical_formula_weight         425.79
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/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                 91.5750(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   12.8509(9)
_cell_length_b                   14.1392(10)
_cell_length_c                   28.232(2)
_cell_measurement_temperature    144.5(2)
_cell_volume                     5127.9(6)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      144.5(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_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  0.0838
_diffrn_reflns_av_sigmaI/netI    0.1001
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       -33
_diffrn_reflns_number            29853
_diffrn_reflns_theta_full        25.04
_diffrn_reflns_theta_max         25.04
_diffrn_reflns_theta_min         1.59
_exptl_absorpt_coefficient_mu    0.091
_exptl_absorpt_correction_T_max  0.9865
_exptl_absorpt_correction_T_min  0.9820
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.103
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1800
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.17
_exptl_crystal_size_min          0.15
_refine_diff_density_max         1.532
_refine_diff_density_min         -0.278
_refine_diff_density_rms         0.131
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.165
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     568
_refine_ls_number_reflns         9055
_refine_ls_number_restraints     6
_refine_ls_restrained_S_all      1.168
_refine_ls_R_factor_all          0.2629
_refine_ls_R_factor_gt           0.1371
_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^)+(0.2000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.3553
_refine_ls_wR_factor_ref         0.4279
_reflns_number_gt                3364
_reflns_number_total             9055
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ma3007625_si_002.cif
_cod_data_source_block           wyy
_cod_original_cell_volume        5127.8(6)
_cod_original_sg_symbol_H-M      P2(1)/C
_cod_original_formula_sum        'C28 H25 Mg O2.50'
_cod_database_code               1508546