Syntheses and Structural Characterizations of Anionic Borane-Capped Ammonia Borane Oligomers: Evidence for Ammonia Borane H2 Release via a Base-Promoted Anionic Dehydropolymerization Mechanism
William C. Ewing; Allegra Marchione; Daniel W. Himmelberger; Patrick J. Carroll; Larry G. Sneddon; Journal of the American Chemical Society 133 (2011) 17093–17099; doi:10.1021/ja207971h

data_4107007
_publ_section_title
;
 Syntheses and Structural Characterizations of Anionic Borane-Capped
 Ammonia Borane Oligomers: Evidence for Ammonia Borane H2 Release via a
 Base-Promoted Anionic Dehydropolymerization Mechanism
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              17093
_journal_page_last               17099
_journal_paper_doi               10.1021/ja207971h
_journal_volume                  133
_journal_year                    2011
_chemical_formula_sum            'C18 H56 B4 N7 P'
_chemical_formula_weight         444.91
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      14
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 101.029(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   17.8873(8)
_cell_length_b                   10.4153(5)
_cell_length_c                   15.5540(7)
_cell_measurement_temperature    143(1)
_cell_volume                     2844.2(2)
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      143(1)
_diffrn_measured_fraction_theta_full 0.990
_diffrn_measured_fraction_theta_max 0.990
_diffrn_measurement_device       'CCD Area Detector'
_diffrn_measurement_device_type  'Bruker APEXII'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0249
_diffrn_reflns_av_sigmaI/netI    0.0148
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -21
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            37499
_diffrn_reflns_theta_full        25.11
_diffrn_reflns_theta_max         25.11
_diffrn_reflns_theta_min         2.27
_exptl_absorpt_coefficient_mu    0.115
_exptl_absorpt_correction_T_max  0.7452
_exptl_absorpt_correction_T_min  0.6966
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 2007)'
_exptl_crystal_density_diffrn    1.039
_exptl_crystal_F_000             992
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.257
_refine_diff_density_min         -0.275
_refine_diff_density_rms         0.032
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.990
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     496
_refine_ls_number_reflns         5031
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.990
_refine_ls_R_factor_all          0.0367
_refine_ls_R_factor_gt           0.0315
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0419P)^2^+1.1427P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0791
_refine_ls_wR_factor_ref         0.0829
_reflns_number_gt                4461
_reflns_number_total             5031
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja207971h_si_003.cif
_cod_data_source_block           UP3393-CMPD2a
_cod_original_sg_symbol_H-M      'P 21/c '
_cod_database_code               4107007