Highly 3,4-Selective Living Polymerization of Isoprene with Rare Earth Metal Fluorenyl N-Heterocyclic Carbene Precursors
Wang, Baoli; Cui, Dongmei; Lv, Kui; Macromolecules 41 (2008) 1983–; doi:10.1021/ma702505n

data_1504423
_publ_section_title
;
 Highly 3,4-Selective Living Polymerization of Isoprene with Rare Earth
 Metal Fluorenyl N-Heterocyclic Carbene Precursors
;
_journal_issue                   6
_journal_name_full               Macromolecules
_journal_page_first              1983
_journal_paper_doi               10.1021/ma702505n
_journal_volume                  41
_journal_year                    2008
_chemical_formula_sum            'C38.5 H51 N2 Sc Si2'
_chemical_formula_weight         642.95
_space_group_IT_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                 117.000(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   37.871(4)
_cell_length_b                   11.0322(11)
_cell_length_c                   20.2313(18)
_cell_measurement_temperature    187(2)
_cell_volume                     7531.4(13)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      187(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_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  0.0884
_diffrn_reflns_av_sigmaI/netI    0.1186
_diffrn_reflns_limit_h_max       46
_diffrn_reflns_limit_h_min       -34
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            20677
_diffrn_reflns_theta_full        26.02
_diffrn_reflns_theta_max         26.02
_diffrn_reflns_theta_min         1.94
_exptl_absorpt_coefficient_mu    0.286
_exptl_absorpt_correction_T_max  0.9892
_exptl_absorpt_correction_T_min  0.9188
_exptl_crystal_density_diffrn    1.134
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             2760
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.304
_refine_diff_density_min         -0.244
_refine_diff_density_rms         0.056
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.986
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     438
_refine_ls_number_reflns         7392
_refine_ls_number_restraints     60
_refine_ls_restrained_S_all      0.990
_refine_ls_R_factor_all          0.1474
_refine_ls_R_factor_gt           0.0736
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0573P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1309
_refine_ls_wR_factor_ref         0.1583
_reflns_number_gt                3919
_reflns_number_total             7392
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ma702505n-file004.cif
_cod_data_source_block           r253m
_cod_original_cell_volume        7531.4(12)
_cod_original_formula_sum        'C38.50 H51 N2 Sc Si2'
_cod_database_code               1504423