X-ray Crystal Structures, Packing Behavior, and Thermal Stability Studies of a Homologous Series ofn-Alkyl-Substituted Polyhedral Oligomeric Silsesquioxanes
El Aziz, Youssef; Bassindale, Alan R.; Taylor, Peter G.; Stephenson, Richard A.; Hursthouse, Michael B.; Harrington, Ross W.; Clegg, William; Macromolecules 46 (2013) 988–; doi:10.1021/ma302229v

data_1508834
_publ_section_title
;
 X-ray Crystal Structures, Packing Behavior, and Thermal Stability Studies
 of a Homologous Series ofn-Alkyl-Substituted Polyhedral Oligomeric
 Silsesquioxanes
;
_journal_issue                   3
_journal_name_full               Macromolecules
_journal_page_first              988
_journal_paper_doi               10.1021/ma302229v
_journal_volume                  46
_journal_year                    2013
_chemical_formula_moiety         'C32 H72 O12 Si8'
_chemical_formula_sum            'C32 H72 O12 Si8'
_chemical_formula_weight         873.62
_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                75.877(6)
_cell_angle_beta                 80.373(4)
_cell_angle_gamma                80.569(5)
_cell_formula_units_Z            1
_cell_length_a                   9.5947(9)
_cell_length_b                   9.6312(8)
_cell_length_c                   13.6739(13)
_cell_measurement_reflns_used    55641
_cell_measurement_temperature    120(2)
_cell_measurement_theta_max      27.48
_cell_measurement_theta_min      2.91
_cell_volume                     1198.09(19)
_computing_cell_refinement
'DENZO (Otwinowski & Minor, 1997) & COLLECT (Hooft, R.W.W., 1998)'
_computing_data_collection       'COLLECT (Hooft, R.W.W., 1998)'
_computing_data_reduction
'DENZO (Otwinowski & Minor, 1997) & COLLECT (Hooft, R.W.W., 1998)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      120(2)
_diffrn_detector_area_resol_mean 9.091
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'Bruker-Nonius Roper CCD'
_diffrn_measurement_method       '\f & \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'Bruker-Nonius FR591 rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0877
_diffrn_reflns_av_sigmaI/netI    0.0914
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            23850
_diffrn_reflns_theta_full        27.48
_diffrn_reflns_theta_max         27.48
_diffrn_reflns_theta_min         2.96
_exptl_absorpt_coefficient_mu    0.274
_exptl_absorpt_correction_T_max  0.986
_exptl_absorpt_correction_T_min  0.947
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS 2007/2 (Sheldrick, G.M., 2007)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.211
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       fragment
_exptl_crystal_F_000             472
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.08
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.341
_refine_diff_density_min         -0.456
_refine_diff_density_rms         0.075
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.022
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     239
_refine_ls_number_reflns         5466
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.022
_refine_ls_R_factor_all          0.1123
_refine_ls_R_factor_gt           0.0599
_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^)+(0.0507P)^2^+0.7067P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1185
_refine_ls_wR_factor_ref         0.1372
_reflns_number_gt                3474
_reflns_number_total             5466
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            ma302229v_si_001.cif
_cod_data_source_block           2008src1201_4
_cod_database_code               1508834