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_4309845
_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         'C18 H30 As Cl2 N '
_chemical_formula_sum            'C18 H30 As Cl2 N'
_chemical_formula_weight         406.27
_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                   16.412(3)
_cell_length_b                   25.188(2)
_cell_length_c                   10.088(3)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      38.2
_cell_measurement_theta_min      30.8
_cell_volume                     4170.2(15)
_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 0.985
_diffrn_measured_fraction_theta_max 0.985
_diffrn_measurement_device       'Rigaku AFC5R'
_diffrn_measurement_method       \w-2\q
_diffrn_orient_matrix_UB_11      0.04395
_diffrn_orient_matrix_UB_12      -0.02555
_diffrn_orient_matrix_UB_13      -0.02538
_diffrn_orient_matrix_UB_21      -0.03838
_diffrn_orient_matrix_UB_22      -0.03030
_diffrn_orient_matrix_UB_23      0.01426
_diffrn_orient_matrix_UB_31      -0.01755
_diffrn_orient_matrix_UB_32      0.00228
_diffrn_orient_matrix_UB_33      -0.09475
_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  0.00000
_diffrn_reflns_av_sigmaI/netI    0.1038
_diffrn_reflns_limit_h_max       19
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       29
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            3825
_diffrn_reflns_reduction_process 'Lp corrections applied'
_diffrn_reflns_theta_full        63.51
_diffrn_reflns_theta_max         63.51
_diffrn_reflns_theta_min         2.69
_diffrn_standards_decay_%        -4.14
_diffrn_standards_interval_count 150
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    4.524
_exptl_absorpt_correction_T_max  0.3551
_exptl_absorpt_correction_T_min  0.1849
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details
;
North, Phillips & Mathews (1968)
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.294
_exptl_crystal_density_meas      ?
_exptl_crystal_description       clump
_exptl_crystal_F_000             1696.00
_exptl_crystal_size_max          0.48
_exptl_crystal_size_mid          0.31
_exptl_crystal_size_min          0.23
_refine_diff_density_max         0.411
_refine_diff_density_min         -0.512
_refine_diff_density_rms         0.077
_refine_ls_extinction_coef       0.00038(5)
_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   0.999
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_constraints    0
_refine_ls_number_parameters     218
_refine_ls_number_reflns         3366
_refine_ls_number_restraints     108
_refine_ls_restrained_S_all      1.017
_refine_ls_R_factor_all          0.1551
_refine_ls_R_factor_gt           0.0442
_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^)+(0.0707P)^2^+2.1151P] where P=(Fo^2^+2Fc^2^)/3
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1169
_refine_ls_wR_factor_ref         0.1560
_reflns_number_gt                1476
_reflns_number_total             3366
_reflns_threshold_expression     I>2.00\s(I)
_cod_data_source_file            ic050770hsi20050513_022640_5.cif
_cod_data_source_block           Mes*(H)NAsCl2
_cod_original_cell_volume        4170(1)
_cod_original_sg_symbol_Hall     '-P 2ac 2ab '
_cod_original_sg_symbol_H-M      'P b c a '
_cod_original_formula_sum        'C18 H30 As Cl2 N '
_cod_database_code               4309845