# Electronic Supplementary Material (ESI) for Chemical Science
# This journal is © The Royal Society of Chemistry 2013

#######################################################################
#
#                 Cambridge Crystallographic Data Centre
#                                CCDC 
# 
#######################################################################
# 
#  This CIF contains data from an original supplementary publication
#  deposited with the CCDC, and may include chemical, crystal,
#  experimental, refinement, atomic coordinates,
#  anisotropic displacement parameters and molecular geometry data,
#  as required by the journal to which it was submitted.
#
#  This CIF is provided on the understanding that it is used for bona
#  fide research purposes only. It may contain copyright material
#  of the CCDC or of third parties, and may not be copied or further
#  disseminated in any form, whether machine-readable or not,
#  except for the purpose of generating routine backup copies
#  on your local computer system.
# 
#  For further information on the CCDC, data deposition and
#  data retrieval see:
#                         www.ccdc.cam.ac.uk
#
#  Bona fide researchers may freely download Mercury and enCIFer
#  from this site to visualise CIF-encoded structures and 
#  to carry out CIF format checking respectively.
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data_691j
#TrackingRef '691j.cif'


_audit_creation_method           SHELXL-97
_chemical_name_systematic        
;
?
;
_chemical_name_common            ?
_chemical_melting_point          ?
_chemical_formula_moiety         ?
_chemical_formula_sum            'C23.50 H56 Si6'
_chemical_formula_weight         507.22

loop_
_atom_type_symbol
_atom_type_description
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
_atom_type_scat_source
C C 0.0033 0.0016 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
H H 0.0000 0.0000 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
Si Si 0.0817 0.0704 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'

_symmetry_cell_setting           Monoclinic
_symmetry_space_group_name_H-M   C2/c

loop_
_symmetry_equiv_pos_as_xyz
'x, y, z'
'-x, y, -z+1/2'
'x+1/2, y+1/2, z'
'-x+1/2, y+1/2, -z+1/2'
'-x, -y, -z'
'x, -y, z-1/2'
'-x+1/2, -y+1/2, -z'
'x+1/2, -y+1/2, z-1/2'

_cell_length_a                   17.135(3)
_cell_length_b                   9.4044(19)
_cell_length_c                   20.723(4)
_cell_angle_alpha                90.00
_cell_angle_beta                 101.54(3)
_cell_angle_gamma                90.00
_cell_volume                     3271.9(11)
_cell_formula_units_Z            4
_cell_measurement_temperature    100(2)
_cell_measurement_reflns_used    8436
_cell_measurement_theta_min      4.847
_cell_measurement_theta_max      53.564

_exptl_crystal_description       plates
_exptl_crystal_colour            colorless
_exptl_crystal_size_max          0.34
_exptl_crystal_size_mid          0.28
_exptl_crystal_size_min          0.20
_exptl_crystal_density_meas      ?
_exptl_crystal_density_diffrn    1.030
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             1124
_exptl_absorpt_coefficient_mu    0.265
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_correction_T_min  0.9154
_exptl_absorpt_correction_T_max  0.9490
_exptl_absorpt_process_details   SADABS

_exptl_special_details           
;
?
;

_diffrn_ambient_temperature      100(2)
_diffrn_radiation_wavelength     0.71073
_diffrn_radiation_type           MoK\a
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_monochromator  graphite
_diffrn_measurement_device_type  'SMART APEX'
_diffrn_measurement_method       '\w scans'
_diffrn_detector_area_resol_mean ?
_diffrn_standards_number         ?
_diffrn_standards_interval_count ?
_diffrn_standards_interval_time  ?
_diffrn_standards_decay_%        ?
_diffrn_reflns_number            12948
_diffrn_reflns_av_R_equivalents  0.0268
_diffrn_reflns_av_sigmaI/netI    0.0245
_diffrn_reflns_limit_h_min       -21
_diffrn_reflns_limit_h_max       21
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_limit_l_max       26
_diffrn_reflns_theta_min         2.01
_diffrn_reflns_theta_max         26.79
_reflns_number_total             3486
_reflns_number_gt                3262
_reflns_threshold_expression     >2sigma(I)

_computing_data_collection       'Bruker XSCANS'
_computing_cell_refinement       'Bruker XSCANS'
_computing_data_reduction        'Bruker SHELXTL'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'

_refine_special_details          
;
Refinement of F^2^ against ALL reflections. The weighted R-factor wR and
goodness of fit S are based on F^2^, conventional R-factors R are based
on F, with F set to zero for negative F^2^. The threshold expression of
F^2^ > 2sigma(F^2^) is used only for calculating R-factors(gt) etc. and is
not relevant to the choice of reflections for refinement. R-factors based
on F^2^ are statistically about twice as large as those based on F, and R-
factors based on ALL data will be even larger.
;

_refine_ls_structure_factor_coef Fsqd
_refine_ls_matrix_type           full
_refine_ls_weighting_scheme      calc
_refine_ls_weighting_details     
'calc w=1/[\s^2^(Fo^2^)+(0.0445P)^2^+2.1904P] where P=(Fo^2^+2Fc^2^)/3'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_atom_sites_solution_hydrogens   geom
_refine_ls_hydrogen_treatment    constr
_refine_ls_extinction_method     none
_refine_ls_extinction_coef       ?
_refine_ls_number_reflns         3486
_refine_ls_number_parameters     144
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0332
_refine_ls_R_factor_gt           0.0311
_refine_ls_wR_factor_ref         0.0837
_refine_ls_wR_factor_gt          0.0819
_refine_ls_goodness_of_fit_ref   1.070
_refine_ls_restrained_S_all      1.070
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000

loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_adp_type
_atom_site_occupancy
_atom_site_symmetry_multiplicity
_atom_site_calc_flag
_atom_site_refinement_flags
_atom_site_disorder_assembly
_atom_site_disorder_group
Si1 Si 0.189171(18) 0.79585(3) 0.426291(15) 0.01326(10) Uani 1 1 d . . .
Si2 Si 0.09721(2) 0.61091(4) 0.389446(17) 0.01782(10) Uani 1 1 d . . .
Si3 Si 0.16831(2) 0.98443(4) 0.348948(17) 0.01980(11) Uani 1 1 d . . .
C1 C 0.16931(7) 0.84469(12) 0.50972(6) 0.0149(2) Uani 1 1 d . . .
C2 C 0.28832(7) 0.70508(12) 0.43299(6) 0.0154(2) Uani 1 1 d . . .
C3 C 0.09730(7) 0.94117(13) 0.50770(6) 0.0188(3) Uani 1 1 d . . .
H3A H 0.0683 0.9119 0.5423 0.023 Uiso 1 1 calc R . .
H3B H 0.0606 0.9316 0.4645 0.023 Uiso 1 1 calc R . .
C4 C 0.12377(8) 1.09657(14) 0.51858(7) 0.0253(3) Uani 1 1 d . . .
H4A H 0.1558 1.1077 0.5631 0.038 Uiso 1 1 calc R . .
H4B H 0.0767 1.1580 0.5134 0.038 Uiso 1 1 calc R . .
H4C H 0.1557 1.1233 0.4862 0.038 Uiso 1 1 calc R . .
C5 C 0.31459(8) 0.67743(14) 0.36778(6) 0.0206(3) Uani 1 1 d . . .
H5A H 0.2673 0.6784 0.3315 0.025 Uiso 1 1 calc R . .
H5B H 0.3391 0.5819 0.3691 0.025 Uiso 1 1 calc R . .
C6 C 0.37440(9) 0.78857(16) 0.35391(7) 0.0288(3) Uani 1 1 d . . .
H6A H 0.3502 0.8833 0.3522 0.043 Uiso 1 1 calc R . .
H6B H 0.3892 0.7676 0.3116 0.043 Uiso 1 1 calc R . .
H6C H 0.4221 0.7860 0.3891 0.043 Uiso 1 1 calc R . .
C7 C 0.10167(11) 0.48754(17) 0.46102(8) 0.0402(4) Uani 1 1 d . . .
H7A H 0.0839 0.5378 0.4969 0.060 Uiso 1 1 calc R . .
H7B H 0.1566 0.4546 0.4761 0.060 Uiso 1 1 calc R . .
H7C H 0.0669 0.4057 0.4474 0.060 Uiso 1 1 calc R . .
C8 C 0.12415(10) 0.50492(16) 0.32016(8) 0.0333(3) Uani 1 1 d . . .
H8A H 0.1773 0.4637 0.3345 0.050 Uiso 1 1 calc R . .
H8B H 0.1240 0.5673 0.2822 0.050 Uiso 1 1 calc R . .
H8C H 0.0852 0.4285 0.3076 0.050 Uiso 1 1 calc R . .
C9 C -0.00774(8) 0.67450(17) 0.36082(9) 0.0364(4) Uani 1 1 d . . .
H9A H -0.0431 0.5925 0.3493 0.055 Uiso 1 1 calc R . .
H9B H -0.0106 0.7355 0.3221 0.055 Uiso 1 1 calc R . .
H9C H -0.0244 0.7287 0.3961 0.055 Uiso 1 1 calc R . .
C10 C 0.17259(10) 0.91100(17) 0.26544(7) 0.0310(3) Uani 1 1 d . . .
H10A H 0.1517 0.9817 0.2316 0.046 Uiso 1 1 calc R . .
H10B H 0.1403 0.8243 0.2576 0.046 Uiso 1 1 calc R . .
H10C H 0.2279 0.8887 0.2635 0.046 Uiso 1 1 calc R . .
C11 C 0.06631(9) 1.06549(16) 0.34097(7) 0.0293(3) Uani 1 1 d . . .
H11A H 0.0573 1.1337 0.3045 0.044 Uiso 1 1 calc R . .
H11B H 0.0627 1.1145 0.3820 0.044 Uiso 1 1 calc R . .
H11C H 0.0259 0.9904 0.3323 0.044 Uiso 1 1 calc R . .
C12 C 0.24261(9) 1.13326(15) 0.36816(8) 0.0303(3) Uani 1 1 d . . .
H12A H 0.2967 1.0944 0.3750 0.045 Uiso 1 1 calc R . .
H12B H 0.2352 1.1824 0.4082 0.045 Uiso 1 1 calc R . .
H12C H 0.2347 1.2006 0.3313 0.045 Uiso 1 1 calc R . .

loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_23
_atom_site_aniso_U_13
_atom_site_aniso_U_12
Si1 0.01342(17) 0.01361(17) 0.01234(17) 0.00042(11) 0.00163(12) 0.00044(11)
Si2 0.01804(18) 0.01662(18) 0.01755(18) -0.00116(13) 0.00056(13) -0.00245(12)
Si3 0.02161(19) 0.01782(19) 0.01848(19) 0.00516(13) 0.00045(14) -0.00122(13)
C1 0.0135(5) 0.0139(5) 0.0179(6) -0.0021(4) 0.0044(4) -0.0006(4)
C2 0.0151(5) 0.0157(6) 0.0164(6) -0.0022(4) 0.0053(4) -0.0011(4)
C3 0.0156(6) 0.0195(6) 0.0212(6) -0.0016(5) 0.0035(5) 0.0033(5)
C4 0.0244(7) 0.0185(6) 0.0330(8) -0.0035(5) 0.0058(6) 0.0041(5)
C5 0.0221(6) 0.0253(7) 0.0155(6) -0.0022(5) 0.0061(5) 0.0018(5)
C6 0.0271(7) 0.0363(8) 0.0264(7) 0.0024(6) 0.0137(6) -0.0010(6)
C7 0.0520(10) 0.0329(8) 0.0315(8) 0.0085(7) -0.0016(7) -0.0209(7)
C8 0.0389(9) 0.0257(7) 0.0362(8) -0.0128(6) 0.0096(7) -0.0046(6)
C9 0.0194(7) 0.0343(8) 0.0515(10) -0.0129(7) -0.0027(6) -0.0021(6)
C10 0.0415(9) 0.0332(8) 0.0170(6) 0.0072(6) 0.0028(6) -0.0020(6)
C11 0.0262(7) 0.0262(7) 0.0321(8) 0.0099(6) -0.0021(6) 0.0041(6)
C12 0.0303(7) 0.0217(7) 0.0386(8) 0.0053(6) 0.0060(6) -0.0052(6)

_geom_special_details            
;
All esds (except the esd in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell esds are taken
into account individually in the estimation of esds in distances, angles
and torsion angles; correlations between esds in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell esds is used for estimating esds involving l.s. planes.
;

loop_
_geom_bond_atom_site_label_1
_geom_bond_atom_site_label_2
_geom_bond_distance
_geom_bond_site_symmetry_2
_geom_bond_publ_flag
Si1 C2 1.8815(13) . ?
Si1 C1 1.8845(13) . ?
Si1 Si2 2.3685(6) . ?
Si1 Si3 2.3690(6) . ?
Si2 C7 1.8725(16) . ?
Si2 C9 1.8753(16) . ?
Si2 C8 1.8797(15) . ?
Si3 C10 1.8781(15) . ?
Si3 C12 1.8804(15) . ?
Si3 C11 1.8836(15) . ?
C1 C2 1.3456(18) 7_566 ?
C1 C3 1.5254(16) . ?
C2 C1 1.3456(18) 7_566 ?
C2 C5 1.5297(16) . ?
C3 C4 1.5335(18) . ?
C5 C6 1.5307(19) . ?

loop_
_geom_angle_atom_site_label_1
_geom_angle_atom_site_label_2
_geom_angle_atom_site_label_3
_geom_angle
_geom_angle_site_symmetry_1
_geom_angle_site_symmetry_3
_geom_angle_publ_flag
C2 Si1 C1 111.66(6) . . ?
C2 Si1 Si2 102.90(4) . . ?
C1 Si1 Si2 104.13(4) . . ?
C2 Si1 Si3 113.66(4) . . ?
C1 Si1 Si3 114.06(4) . . ?
Si2 Si1 Si3 109.33(3) . . ?
C7 Si2 C9 109.44(9) . . ?
C7 Si2 C8 107.41(8) . . ?
C9 Si2 C8 107.09(8) . . ?
C7 Si2 Si1 106.29(6) . . ?
C9 Si2 Si1 113.69(5) . . ?
C8 Si2 Si1 112.73(5) . . ?
C10 Si3 C12 108.62(7) . . ?
C10 Si3 C11 105.93(8) . . ?
C12 Si3 C11 107.12(7) . . ?
C10 Si3 Si1 108.64(5) . . ?
C12 Si3 Si1 114.20(5) . . ?
C11 Si3 Si1 111.97(5) . . ?
C2 C1 C3 121.46(11) 7_566 . ?
C2 C1 Si1 124.05(9) 7_566 . ?
C3 C1 Si1 114.42(9) . . ?
C1 C2 C5 121.20(11) 7_566 . ?
C1 C2 Si1 122.87(9) 7_566 . ?
C5 C2 Si1 115.65(9) . . ?
C1 C3 C4 110.42(10) . . ?
C2 C5 C6 112.10(11) . . ?

loop_
_geom_torsion_atom_site_label_1
_geom_torsion_atom_site_label_2
_geom_torsion_atom_site_label_3
_geom_torsion_atom_site_label_4
_geom_torsion
_geom_torsion_site_symmetry_1
_geom_torsion_site_symmetry_2
_geom_torsion_site_symmetry_3
_geom_torsion_site_symmetry_4
_geom_torsion_publ_flag
C2 Si1 Si2 C7 71.60(8) . . . . ?
C1 Si1 Si2 C7 -45.02(8) . . . . ?
Si3 Si1 Si2 C7 -167.29(7) . . . . ?
C2 Si1 Si2 C9 -167.95(7) . . . . ?
C1 Si1 Si2 C9 75.43(8) . . . . ?
Si3 Si1 Si2 C9 -46.84(7) . . . . ?
C2 Si1 Si2 C8 -45.82(7) . . . . ?
C1 Si1 Si2 C8 -162.43(7) . . . . ?
Si3 Si1 Si2 C8 75.30(6) . . . . ?
C2 Si1 Si3 C10 60.43(7) . . . . ?
C1 Si1 Si3 C10 -170.00(7) . . . . ?
Si2 Si1 Si3 C10 -53.90(6) . . . . ?
C2 Si1 Si3 C12 -60.96(7) . . . . ?
C1 Si1 Si3 C12 68.60(7) . . . . ?
Si2 Si1 Si3 C12 -175.30(6) . . . . ?
C2 Si1 Si3 C11 177.08(7) . . . . ?
C1 Si1 Si3 C11 -53.36(7) . . . . ?
Si2 Si1 Si3 C11 62.75(6) . . . . ?
C2 Si1 C1 C2 -13.26(14) . . . 7_566 ?
Si2 Si1 C1 C2 97.08(10) . . . 7_566 ?
Si3 Si1 C1 C2 -143.82(10) . . . 7_566 ?
C2 Si1 C1 C3 169.79(8) . . . . ?
Si2 Si1 C1 C3 -79.87(9) . . . . ?
Si3 Si1 C1 C3 39.22(9) . . . . ?
C1 Si1 C2 C1 13.08(14) . . . 7_566 ?
Si2 Si1 C2 C1 -98.05(10) . . . 7_566 ?
Si3 Si1 C2 C1 143.84(9) . . . 7_566 ?
C1 Si1 C2 C5 -172.83(8) . . . . ?
Si2 Si1 C2 C5 76.05(9) . . . . ?
Si3 Si1 C2 C5 -42.06(10) . . . . ?
C2 C1 C3 C4 84.84(15) 7_566 . . . ?
Si1 C1 C3 C4 -98.11(11) . . . . ?
C1 C2 C5 C6 -86.01(15) 7_566 . . . ?
Si1 C2 C5 C6 99.79(11) . . . . ?

_diffrn_measured_fraction_theta_max 0.996
_diffrn_reflns_theta_full        26.79
_diffrn_measured_fraction_theta_full 0.996
_refine_diff_density_max         0.416
_refine_diff_density_min         -0.169
_refine_diff_density_rms         0.052


_database_code_depnum_ccdc_archive 'CCDC 775978'