Synthesis and structures of tris(2-pyridyl)aluminate sandwich compounds [{RAl(2-py')2}2M] (py' = 2-pyridyl, M = Ca, Mn, Fe).
García-Rodríguez, Raúl; Bullock, Thomas H.; McPartlin, Mary; Wright, Dominic S.; Dalton transactions (Cambridge, England : 2003) 43 (2014) 14045–14053; doi:10.1039/c4dt00951g

data_7032438
_publ_section_title
;
 Synthesis and structures of tris(2-pyridyl)aluminate sandwich compounds
 [{RAl(2-py')2}2M] (py' = 2-pyridyl, M = Ca, Mn, Fe).
;
_journal_issue                   37
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              14045
_journal_page_last               14053
_journal_paper_doi               10.1039/c4dt00951g
_journal_volume                  43
_journal_year                    2014
_chemical_absolute_configuration
;
 The absolute structure was NOT determined. 439 Friedel pairs were
 averaged for the refinement.  Without Friedel averaging, the Flack
 parameter is ambiguous (ca 0.43) and attempts to refine as a twin
 did not improve matters.  Not too surprising, considering the problems
 of poor data and disorder (see _refine_special_details).
;
_chemical_formula_moiety         'C40 H46 Al2 Cl Li Mn N6'
_chemical_formula_sum            'C40 H46 Al2 Cl Li Mn N6'
_chemical_formula_weight         762.12
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           146
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  'R 3'
_symmetry_space_group_name_H-M   'R 3 :H'
_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
_cell_angle_gamma                120.00
_cell_formula_units_Z            3
_cell_length_a                   12.543(1)
_cell_length_b                   12.543(1)
_cell_length_c                   22.339(2)
_cell_measurement_reflns_used    2280
_cell_measurement_temperature    250(2)
_cell_measurement_theta_max      41.20
_cell_measurement_theta_min      4.53
_cell_volume                     3043.7(4)
_computing_cell_refinement       'refinement of XYZ centroids > 20sigma(I)'
_computing_data_collection       'Bruker software package, narrow-frames'
_computing_data_reduction
;
 Bruker SAINT software package, narrow frame algorithm
;
_computing_publication_material  'SHELXL-97 (Sheldrick 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick 1997)'
_computing_structure_solution    'SIR-92 (Altomare et al. 1994)'
_diffrn_ambient_temperature      250(2)
_diffrn_measured_fraction_theta_full 0.989
_diffrn_measured_fraction_theta_max 0.989
_diffrn_measurement_device_type  'Bruker QUEST D8 CCD'
_diffrn_measurement_method       'Thin slice \w and \f scans'
_diffrn_radiation_source         '30W microfocus sealed tube, Quazar optics'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0314
_diffrn_reflns_av_sigmaI/netI    0.0309
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            2317
_diffrn_reflns_theta_full        41.20
_diffrn_reflns_theta_max         41.20
_diffrn_reflns_theta_min         4.53
_exptl_absorpt_coefficient_mu    3.938
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.789
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
multi-scan from symmetry-related measurements (SADABS) 
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.247
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1197
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.844
_refine_diff_density_min         -0.747
_refine_diff_density_rms         0.083
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.47(4)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.050
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     79
_refine_ls_number_reflns         881
_refine_ls_number_restraints     10
_refine_ls_restrained_S_all      1.047
_refine_ls_R_factor_all          0.0964
_refine_ls_R_factor_gt           0.0962
_refine_ls_shift/su_max          0.008
_refine_ls_shift/su_mean         0.002
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1123P)^2^+65.9986P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2387
_refine_ls_wR_factor_ref         0.2389
_reflns_number_gt                879
_reflns_number_total             881
_reflns_threshold_expression     >2sigma(I)
_cod_duplicate_entry             7031967
_cod_data_source_file            c4dt00951g2.cif
_cod_data_source_block           dw1444
_cod_original_sg_symbol_H-M      R3
_cod_database_code               7032438