Dissociation of 2,4-Bis(2,4,6-tri-tert-butylphenyl)-cyclo-1,3-dipnicta-2,4-diazanes (pnict = P, As, Sb) Imposed by Substituent Steric Strain: A Cyclobutane/Olefin Analogy
Neil Burford; T. Stanley Cameron; Charles L. B. Macdonald; Katherine N. Robertson; Robert Schurko; Denise Walsh; Robert McDonald; Roderick E. Wasylishen; Inorganic Chemistry 44 (2005) 8058–8064; doi:10.1021/ic050770h

data_4309846
_publ_contact_author_address
;
Department of Chemistry
Dalhousie University
Halifax, Nova Scotia
B3H 4J3
Canada
;
_publ_contact_author_email       ' neil.burford@dal.ca '
_publ_contact_author_fax         ' (902) 494-1310 '
_publ_contact_author_name        ' Neil Burford'
_publ_contact_author_phone       ' (902) 494-3190 '
_publ_section_title
;
Dissociation of
2,4-Bis(2,4,6-tri-tert-butylphenyl)-cyclo-1,3-dipnicta-2,4-diazanes (pnict
= P, As, Sb) Imposed by Substituent Steric Strain: A Cyclobutane/Olefin
Analogy
;
_journal_name_full               'Inorganic Chemistry'
_journal_page_first              8058
_journal_page_last               8064
_journal_paper_doi               10.1021/ic050770h
_journal_volume                  44
_journal_year                    2005
_chemical_formula_moiety         'C21 H38 As Cl2 N Si '
_chemical_formula_sum            'C21 H38 As Cl2 N Si'
_chemical_formula_weight         478.45
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_Int_Tables_number      61
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   19.771(2)
_cell_length_b                   19.607(2)
_cell_length_c                   12.940(2)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      39.0
_cell_measurement_theta_min      35.3
_cell_volume                     5016.2(11)
_computing_cell_refinement       'MSC/AFC Diffractometer Control'
_computing_data_collection       'MSC/AFC Diffractometer Control'
_computing_data_reduction
;
teXsan for Windows version 1.06 (MSC, 1997-1999)
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution
;
SIR92 (Altomare, et. al. 1994)
;
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.987
_diffrn_measured_fraction_theta_max 0.987
_diffrn_measurement_device       'Rigaku AFC5R'
_diffrn_measurement_method       \w-2\q
_diffrn_orient_matrix_UB_11      0.00304
_diffrn_orient_matrix_UB_12      -0.05084
_diffrn_orient_matrix_UB_13      -0.00390
_diffrn_orient_matrix_UB_21      0.05019
_diffrn_orient_matrix_UB_22      0.00277
_diffrn_orient_matrix_UB_23      0.00856
_diffrn_orient_matrix_UB_31      -0.00545
_diffrn_orient_matrix_UB_32      -0.00289
_diffrn_orient_matrix_UB_33      0.07671
_diffrn_radiation_detector       'scintillation counter'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'Rigaku rotating anode'
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.5418
_diffrn_reflns_av_R_equivalents  0.0480
_diffrn_reflns_av_sigmaI/netI    0.0886
_diffrn_reflns_limit_h_max       22
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       0
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            4545
_diffrn_reflns_reduction_process 'Lp corrections applied'
_diffrn_reflns_theta_full        63.49
_diffrn_reflns_theta_max         63.49
_diffrn_reflns_theta_min         3.17
_diffrn_standards_decay_%        0.26
_diffrn_standards_interval_count 150
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    4.279
_exptl_absorpt_correction_T_max  0.4618
_exptl_absorpt_correction_T_min  0.3729
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details
;
North,Phillips & Mathews (1968)
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.267
_exptl_crystal_density_meas      ?
_exptl_crystal_description       block
_exptl_crystal_F_000             2016.00
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.21
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.274
_refine_diff_density_min         -0.405
_refine_diff_density_rms         0.068
_refine_ls_extinction_coef       0.00028(3)
_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   1.013
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_constraints    0
_refine_ls_number_parameters     253
_refine_ls_number_reflns         4058
_refine_ls_number_restraints     60
_refine_ls_restrained_S_all      1.025
_refine_ls_R_factor_all          0.1299
_refine_ls_R_factor_gt           0.0349
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
;
w=1/[\s^2^(Fo^2^)+(0.0372P)^2^+4.0545P] where P=(Fo^2^+2Fc^2^)/3
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0870
_refine_ls_wR_factor_ref         0.1138
_reflns_number_gt                1973
_reflns_number_total             4058
_reflns_threshold_expression     I>2.00\s(I)
_cod_data_source_file            ic050770hsi20050513_022640_6.cif
_cod_data_source_block           Mes*(SiMe3)NAsCl2
_cod_original_cell_volume        5016.3(7)
_cod_original_sg_symbol_Hall     '-P 2ac 2ab '
_cod_original_sg_symbol_H-M      'P b c a '
_cod_original_formula_sum        'C21 H38 As Cl2 N Si '
_cod_database_code               4309846