A missing link in the transformation from asymmetric to symmetric metallofullerene cages implies a top-down fullerene formation mechanism
Jianyuan Zhang; Faye L. Bowles; Daniel W. Bearden; W. Keith Ray; Tim Fuhrer; Youqing Ye; Caitlyn Dixon; Kim Harich; Richard F. Helm; Marilyn M. Olmstead; Alan L. Balch; Harry C. Dorn; Nature Chemistry 5 (2013) 880–885; doi:10.1038/nchem.1748

data_1551874
_publ_section_title
;
 A missing link in the transformation from asymmetric to symmetric
 metallofullerene cages implies a top-down fullerene formation mechanism
;
_journal_name_full               'Nature Chemistry'
_journal_page_first              880
_journal_page_last               885
_journal_paper_doi               10.1038/nchem.1748
_journal_volume                  5
_journal_year                    2013
_chemical_formula_moiety
;
C86 Gd2, C36 H44 N4 Ni, 1.75(C7 H8), 0.25(C6 H6)
;
_chemical_formula_sum            'C135.75 H59.5 Gd2 N4 Ni'
_chemical_formula_weight         2119.58
_chemical_name_common            Gd2C2@C84.Ni(OEP).1.75toluene.0.25benzene
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.00
_cell_angle_beta                 96.261(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   20.4825(7)
_cell_length_b                   14.8334(5)
_cell_length_c                   25.3877(9)
_cell_measurement_reflns_used    9660
_cell_measurement_temperature    90(2)
_cell_measurement_theta_max      34.40
_cell_measurement_theta_min      2.47
_cell_volume                     7667.4(5)
_computing_cell_refinement       'SAINT (Bruker, 2011)'
_computing_data_collection       'Apex 2 (Bruker, 2010)'
_computing_data_reduction        'SAINT (Bruker, 2011)'
_computing_publication_material  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      90(2)
_diffrn_detector_area_resol_mean 8.3
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'APEX II'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  silicon
_diffrn_radiation_source         'beamline 11.3.1 ALS'
_diffrn_radiation_type           synchrotron
_diffrn_radiation_wavelength     0.77490
_diffrn_reflns_av_R_equivalents  0.1192
_diffrn_reflns_av_sigmaI/netI    0.0823
_diffrn_reflns_limit_h_max       31
_diffrn_reflns_limit_h_min       -31
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       -22
_diffrn_reflns_limit_l_max       39
_diffrn_reflns_limit_l_min       -38
_diffrn_reflns_number            224210
_diffrn_reflns_theta_full        36.72
_diffrn_reflns_theta_max         36.72
_diffrn_reflns_theta_min         1.76
_exptl_absorpt_coefficient_mu    2.534
_exptl_absorpt_correction_T_max  0.884
_exptl_absorpt_correction_T_min  0.548
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (sheldrick, 2008)'
_exptl_crystal_colour            black
_exptl_crystal_density_diffrn    1.836
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             4232
_exptl_crystal_size_max          0.27
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.05
_refine_diff_density_max         3.565
_refine_diff_density_min         -1.527
_refine_diff_density_rms         0.204
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.821
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     1353
_refine_ls_number_reflns         29336
_refine_ls_number_restraints     511
_refine_ls_restrained_S_all      1.839
_refine_ls_R_factor_all          0.1632
_refine_ls_R_factor_gt           0.1154
_refine_ls_shift/su_max          0.018
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1000P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.3045
_refine_ls_wR_factor_ref         0.3286
_reflns_number_gt                18147
_reflns_number_total             29336
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            nchem.1748-s2.cif
_cod_data_source_block           fb76
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_original_formula_sum        'C135.75 H59.50 Gd2 N4 Ni'
_cod_database_code               1551874
_shelxl_version_number           2012-5
_shelx_res_checksum              8664