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_1508838
_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         'C48 H104 O12 Si8'
_chemical_formula_sum            'C48 H104 O12 Si8'
_chemical_formula_weight         1098.03
_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                78.122(4)
_cell_angle_beta                 80.489(4)
_cell_angle_gamma                85.953(4)
_cell_formula_units_Z            1
_cell_length_a                   8.664(4)
_cell_length_b                   9.475(4)
_cell_length_c                   20.486(8)
_cell_measurement_reflns_used    973
_cell_measurement_temperature    210(2)
_cell_measurement_theta_max      23.86
_cell_measurement_theta_min      2.54
_cell_volume                     1621.9(12)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_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      210(2)
_diffrn_measured_fraction_theta_full 0.986
_diffrn_measured_fraction_theta_max 0.986
_diffrn_measurement_device_type  'Bruker APEX2 CCD diffractometer'
_diffrn_measurement_method       'thin-slice \w scans'
_diffrn_radiation_monochromator  'silicon 111'
_diffrn_radiation_source         'Daresbury SRS station 9.8'
_diffrn_radiation_type           synchrotron
_diffrn_radiation_wavelength     0.6946
_diffrn_reflns_av_R_equivalents  0.0304
_diffrn_reflns_av_sigmaI/netI    0.0502
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       24
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            11672
_diffrn_reflns_theta_full        24.42
_diffrn_reflns_theta_max         24.42
_diffrn_reflns_theta_min         3.02
_diffrn_standards_decay_%        5
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.215
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.124
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             600
_exptl_crystal_size_max          0.06
_exptl_crystal_size_mid          0.06
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.419
_refine_diff_density_min         -0.331
_refine_diff_density_rms         0.054
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.021
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     307
_refine_ls_number_reflns         5653
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.021
_refine_ls_R_factor_all          0.0964
_refine_ls_R_factor_gt           0.0602
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0955P)^2^+1.0160P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1611
_refine_ls_wR_factor_ref         0.1865
_reflns_number_gt                3609
_reflns_number_total             5653
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            ma302229v_si_001.cif
_cod_data_source_block           ssh0704_6b
_cod_database_code               1508838