Tetramethylcyclopentadienyl vs Cyclopentadienyl Substituents. Synthesis and Structural Characterization of Organolanthanide Compounds Derived from the Versatile Ligand Me2Si(C5Me4H)(C2B10H11)
Zi, Guofu; Yang, Qingchuan; Mak, Thomas C. W.; Xie, Zuowei; Organometallics 20 (2001) 2359–; doi:10.1021/om010031i

data_4077278
_publ_section_title
;
 Tetramethylcyclopentadienyl vs Cyclopentadienyl Substituents. Synthesis
 and Structural Characterization of Organolanthanide Compounds Derived
 from the Versatile Ligand Me2Si(C5Me4H)(C2B10H11)
;
_journal_issue                   11
_journal_name_full               Organometallics
_journal_page_first              2359
_journal_paper_doi               10.1021/om010031i
_journal_volume                  20
_journal_year                    2001
_chemical_formula_sum            'C54 H112 B20 Li4 O7 Si2'
_chemical_formula_weight         1173.58
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           9
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'C -2yc'
_symmetry_space_group_name_H-M   'C 1 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                 90.00(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   38.213(8)
_cell_length_b                   10.460(2)
_cell_length_c                   18.533(4)
_cell_measurement_temperature    293(2)
_cell_volume                     7408(3)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.630
_diffrn_measured_fraction_theta_max 0.630
_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  0.0000
_diffrn_reflns_av_sigmaI/netI    0.0846
_diffrn_reflns_limit_h_max       40
_diffrn_reflns_limit_h_min       -40
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            4683
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         2.30
_exptl_absorpt_coefficient_mu    0.091
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.737
_exptl_absorpt_correction_type   abscor
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.052
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             2528
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.40
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.366
_refine_diff_density_min         -0.331
_refine_diff_density_rms         0.061
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.1(4)
_refine_ls_extinction_coef       0.00000(12)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.195
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     805
_refine_ls_number_reflns         4683
_refine_ls_number_restraints     20
_refine_ls_restrained_S_all      1.194
_refine_ls_R_factor_all          0.1287
_refine_ls_R_factor_gt           0.1092
_refine_ls_shift/su_max          0.985
_refine_ls_shift/su_mean         0.034
_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          0.2779
_refine_ls_wR_factor_ref         0.3002
_reflns_number_gt                3617
_reflns_number_total             4683
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            om010031i.cif
_cod_data_source_block           compound_2
_cod_original_sg_symbol_H-M      Cc
_cod_database_code               4077278