Why Are Silyl Ethers Conformationally Different from Alkyl Ethers? Chair-Chair Conformational Equilibria in Silyloxycyclohexanes and Their Dependence on the Substituents on Silicon. The Wider Roles of Eclipsing, of 1,3-Repulsive Steric Interactions, and of Attractive Steric Interactions
Cecilia H. Marzabadi; J. Edgar Anderson; Jorge Gonzalez-Outeirino; Piers R. J. Gaffney; Christopher G. H. White; Derek A. Tocher; Louis J. Todaro; Journal of the American Chemical Society 125 (2003) 15163–15173; doi:10.1021/ja035936x

data_4114436
_publ_section_title
;
 Why Are Silyl Ethers Conformationally Different from Alkyl Ethers?
 Chair-Chair Conformational Equilibria in Silyloxycyclohexanes and Their
 Dependence on the Substituents on Silicon. The Wider Roles of Eclipsing,
 of 1,3-Repulsive Steric Interactions, and of Attractive Steric
 Interactions
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              15163
_journal_page_last               15173
_journal_paper_doi               10.1021/ja035936x
_journal_volume                  125
_journal_year                    2003
_chemical_formula_sum            'C42 H40 O2 Si2'
_chemical_formula_weight         632.92
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                82.283(2)
_cell_angle_beta                 85.747(2)
_cell_angle_gamma                74.337(2)
_cell_formula_units_Z            1
_cell_length_a                   7.2034(8)
_cell_length_b                   9.7662(10)
_cell_length_c                   12.7749(14)
_cell_measurement_temperature    293(2)
_cell_volume                     856.83(16)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL and local programs'
_computing_structure_refinement  'Bruker SHELXTL'
_computing_structure_solution    'Bruker SHELXTL'
_diffrn_ambient_temperature      566(2)
_diffrn_measured_fraction_theta_full 0.979
_diffrn_measured_fraction_theta_max 0.908
_diffrn_measurement_device_type  'Bruker SMART APEX'
_diffrn_measurement_method       '\w rotation with narrow frames'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0127
_diffrn_reflns_av_sigmaI/netI    0.0338
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -10
_diffrn_reflns_number            5511
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         28.28
_diffrn_reflns_theta_min         1.61
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.139
_exptl_absorpt_correction_T_max  0.9808
_exptl_absorpt_correction_T_min  0.9336
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.227
_exptl_crystal_description       needle
_exptl_crystal_F_000             336
_exptl_crystal_size_max          0.50
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.14
_refine_diff_density_max         0.726
_refine_diff_density_min         -0.307
_refine_diff_density_rms         0.057
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.855
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     208
_refine_ls_number_reflns         3844
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.855
_refine_ls_R_factor_all          0.0675
_refine_ls_R_factor_gt           0.0566
_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^)+(0.2000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1852
_refine_ls_wR_factor_ref         0.2081
_reflns_number_gt                3127
_reflns_number_total             3844
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            ja035936xsi20030904_095615.cif
_cod_data_source_block           str0002
_cod_database_code               4114436