A new route to dilithio boraamidinates: formation and X-ray structures of the dimeric and trimeric clusters {Li2[RB(NBut)2]}x (R = Bun, x = 2 and R = Me, x = 3)
Brask, Justin K.; Chivers, Tristram; Schatte, Gabriele; Chemical Communications  (2000) 1805–; doi:10.1039/b005852l

data_7111072
_publ_section_title
;
 A new route to dilithio boraamidinates: formation and X-ray structures of
 the dimeric and trimeric clusters {Li2[RB(NBut)2]}x (R = Bun, x = 2 and R
 = Me, x = 3)
;
_journal_issue                   18
_journal_name_full               'Chemical Communications'
_journal_page_first              1805
_journal_paper_doi               10.1039/b005852l
_journal_year                    2000
_chemical_formula_moiety         'C24 H54 B2 Li4 N4'
_chemical_formula_sum            'C24 H54 B2 Li4 N4'
_chemical_formula_weight         448.09
_chemical_name_systematic
;
 ?
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.000(5)
_cell_angle_beta                 98.825(5)
_cell_angle_gamma                90.000(5)
_cell_formula_units_Z            4
_cell_length_a                   12.671(5)
_cell_length_b                   17.562(5)
_cell_length_c                   14.026(5)
_cell_measurement_temperature    193(2)
_cell_volume                     3084.2(19)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_computing_molecular_graphics    'ORTEP for Windows; WinGX 1.62'
_computing_publication_material  'WinGX 1.62'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    SIR-97
_diffrn_ambient_temperature      193(2)
_diffrn_measured_fraction_theta_full 0.934
_diffrn_measured_fraction_theta_max 0.934
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0791
_diffrn_reflns_av_sigmaI/netI    0.1831
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            9679
_diffrn_reflns_theta_full        26.39
_diffrn_reflns_theta_max         26.39
_diffrn_reflns_theta_min         1.87
_exptl_absorpt_coefficient_mu    0.053
_exptl_absorpt_correction_T_max  none
_exptl_absorpt_correction_T_min  none
_exptl_absorpt_correction_type   none
_exptl_crystal_density_diffrn    0.965
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             992
_exptl_crystal_size_max          0.55
_exptl_crystal_size_mid          0.33
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.283
_refine_diff_density_min         -0.202
_refine_diff_density_rms         0.054
_refine_ls_extinction_coef       0.0120(11)
_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   0.838
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     353
_refine_ls_number_reflns         5898
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.838
_refine_ls_R_factor_all          0.1826
_refine_ls_R_factor_gt           0.0641
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0638P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1322
_refine_ls_wR_factor_ref         0.1678
_reflns_number_gt                2277
_reflns_number_total             5898
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b005852lsup1.cif
_cod_data_source_block           3
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               7111072