# Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
# 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
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#  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.
#
data_k13cgf1

_audit_creation_method           SHELXL-97
_chemical_name_systematic        
; 
 ? 
;
_chemical_name_common            ?
_chemical_melting_point          ?
_chemical_formula_moiety         ?
_chemical_formula_sum            'C15 H25 B O4 Si'
_chemical_formula_weight         308.25

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'
O O 0.0106 0.0060 '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'
B B 0.0013 0.0007 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'

_symmetry_cell_setting           Orthorhombic
_symmetry_space_group_name_H-M   Pcab

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

_cell_length_a                   12.5000(4)
_cell_length_b                   12.6610(3)
_cell_length_c                   22.0560(7)
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_volume                     3490.64(18)
_cell_formula_units_Z            8
_cell_measurement_temperature    150(2)
_cell_measurement_reflns_used    12786
_cell_measurement_theta_min      2.910
_cell_measurement_theta_max      27.485

_exptl_crystal_description       block
_exptl_crystal_colour            colorless
_exptl_crystal_size_max          0.60
_exptl_crystal_size_mid          0.60
_exptl_crystal_size_min          0.40
_exptl_crystal_density_meas      ?
_exptl_crystal_density_diffrn    1.173
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             1328
_exptl_absorpt_coefficient_mu    0.145
# Absorption correction 

_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_correction_T_min  0.821
_exptl_absorpt_correction_T_max  0.924
_exptl_absorpt_process_details   
;
multi-scan from symmetry-related measurements 
 Sortav (Blessing 1995)
;


_exptl_special_details           
; 
 ? 
;

_diffrn_ambient_temperature      150(2)
_diffrn_radiation_wavelength     0.71073
_diffrn_radiation_type           MoK\a
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_monochromator  'horizonally mounted graphite crystal'
_diffrn_measurement_device_type  '95mm CCD camera on \k-goniostat'
_diffrn_measurement_method       CCD
_diffrn_detector_area_resol_mean ?
_diffrn_standards_number         ?
_diffrn_standards_interval_count ?
_diffrn_standards_interval_time  ?
_diffrn_standards_decay_%        ?
_diffrn_reflns_number            18348
_diffrn_reflns_av_R_equivalents  0.0981
_diffrn_reflns_av_sigmaI/netI    0.1139
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_theta_min         3.60
_diffrn_reflns_theta_max         27.47
_reflns_number_total             3977
_reflns_number_gt                1976
_reflns_threshold_expression     >2sigma(I)

_computing_data_collection       'Collect (Bruker AXS BV 1997-2004)'
_computing_cell_refinement       'HKL Scalepack (Otwinowski & Minor 1997)'
_computing_data_reduction        'Denzo & Scalepack (Otwinowski, Minor 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick 1990)'
_computing_structure_refinement  'SHELXL-97/2 (Sheldrick 1997)'
_computing_molecular_graphics    'ORTEX (P.McArdle 1995)'
_computing_publication_material  'SHELXL-97/2 (Sheldrick 1997)'

_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^)+(0.0756P)^2^+0.0000P] 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         3977
_refine_ls_number_parameters     195
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.1504
_refine_ls_R_factor_gt           0.0573
_refine_ls_wR_factor_ref         0.1581
_refine_ls_wR_factor_gt          0.1244
_refine_ls_goodness_of_fit_ref   0.979
_refine_ls_restrained_S_all      0.979
_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
Si2 Si 1.12418(6) -0.28449(5) 0.37813(3) 0.0302(2) Uani 1 1 d . . .
O1 O 0.99601(14) 0.09824(13) 0.32721(7) 0.0312(5) Uani 1 1 d . . .
O2 O 0.96729(14) 0.11911(12) 0.43431(7) 0.0297(4) Uani 1 1 d . . .
O3 O 0.47589(15) 0.12771(13) 0.34157(8) 0.0373(5) Uani 1 1 d . . .
O4 O 1.12274(15) -0.15626(12) 0.36394(7) 0.0325(5) Uani 1 1 d . . .
C1 C 0.8080(2) 0.12687(17) 0.36472(11) 0.0270(6) Uani 1 1 d . . .
C2 C 0.7635(2) 0.13232(17) 0.30660(12) 0.0305(6) Uani 1 1 d . . .
H2 H 0.8102 0.1349 0.2726 0.037 Uiso 1 1 calc R . .
C3 C 0.6545(2) 0.13412(16) 0.29662(12) 0.0286(6) Uani 1 1 d . . .
H3 H 0.6271 0.1391 0.2565 0.034 Uiso 1 1 calc R . .
C4 C 0.5855(2) 0.12860(17) 0.34556(12) 0.0286(6) Uani 1 1 d . . .
C5 C 0.6263(2) 0.12334(18) 0.40439(11) 0.0311(6) Uani 1 1 d . . .
H5 H 0.5791 0.1202 0.4381 0.037 Uiso 1 1 calc R . .
C6 C 0.7357(2) 0.12275(17) 0.41327(12) 0.0312(7) Uani 1 1 d . . .
H6 H 0.7627 0.1195 0.4535 0.037 Uiso 1 1 calc R . .
C7 C 0.4296(2) 0.1251(2) 0.28236(12) 0.0455(8) Uani 1 1 d . . .
H7A H 0.4523 0.1876 0.2596 0.068 Uiso 1 1 calc R . .
H7B H 0.3515 0.1246 0.2858 0.068 Uiso 1 1 calc R . .
H7C H 0.4534 0.0613 0.2611 0.068 Uiso 1 1 calc R . .
C8 C 1.1072(2) 0.07535(19) 0.33713(11) 0.0290(6) Uani 1 1 d . . .
H8A H 1.1490 0.1415 0.3335 0.035 Uiso 1 1 calc R . .
H8B H 1.1325 0.0263 0.3053 0.035 Uiso 1 1 calc R . .
C9 C 1.0785(2) 0.09876(18) 0.44604(11) 0.0281(6) Uani 1 1 d . . .
H9A H 1.0859 0.0662 0.4866 0.034 Uiso 1 1 calc R . .
H9B H 1.1179 0.1666 0.4464 0.034 Uiso 1 1 calc R . .
C10 C 1.1279(2) 0.02627(17) 0.39914(11) 0.0259(6) Uani 1 1 d . . .
C11 C 1.0748(2) -0.08211(18) 0.40485(11) 0.0298(6) Uani 1 1 d . . .
H11A H 1.0824 -0.1081 0.4470 0.036 Uiso 1 1 calc R . .
H11B H 0.9975 -0.0757 0.3958 0.036 Uiso 1 1 calc R . .
C12 C 0.9885(3) -0.3380(3) 0.3706(2) 0.0973(16) Uani 1 1 d . . .
H12A H 0.9407 -0.3017 0.3990 0.146 Uiso 1 1 calc R . .
H12B H 0.9893 -0.4138 0.3798 0.146 Uiso 1 1 calc R . .
H12C H 0.9630 -0.3272 0.3290 0.146 Uiso 1 1 calc R . .
C13 C 1.1768(3) -0.3092(2) 0.45466(14) 0.0798(13) Uani 1 1 d . . .
H13A H 1.2450 -0.2720 0.4597 0.120 Uiso 1 1 calc R . .
H13B H 1.1880 -0.3852 0.4602 0.120 Uiso 1 1 calc R . .
H13C H 1.1255 -0.2836 0.4849 0.120 Uiso 1 1 calc R . .
C14 C 1.2152(3) -0.3414(2) 0.32187(14) 0.0576(10) Uani 1 1 d . . .
H14A H 1.1875 -0.3277 0.2811 0.086 Uiso 1 1 calc R . .
H14B H 1.2207 -0.4178 0.3283 0.086 Uiso 1 1 calc R . .
H14C H 1.2861 -0.3092 0.3261 0.086 Uiso 1 1 calc R . .
C15 C 1.2479(2) 0.0180(2) 0.40932(12) 0.0370(7) Uani 1 1 d . . .
H15A H 1.2796 -0.0264 0.3777 0.056 Uiso 1 1 calc R . .
H15B H 1.2616 -0.0136 0.4491 0.056 Uiso 1 1 calc R . .
H15C H 1.2798 0.0887 0.4077 0.056 Uiso 1 1 calc R . .
B1 B 0.9307(3) 0.1167(2) 0.37585(14) 0.0289(7) Uani 1 1 d . . .

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
Si2 0.0359(5) 0.0204(4) 0.0344(4) 0.0008(3) 0.0006(4) 0.0014(3)
O1 0.0316(12) 0.0321(10) 0.0298(10) 0.0008(8) 0.0005(9) 0.0033(8)
O2 0.0289(11) 0.0314(10) 0.0287(10) -0.0038(8) -0.0014(9) 0.0060(8)
O3 0.0317(13) 0.0406(11) 0.0396(11) 0.0021(9) -0.0052(10) 0.0008(9)
O4 0.0462(13) 0.0202(9) 0.0310(10) 0.0001(7) 0.0049(9) 0.0010(9)
C1 0.0346(18) 0.0164(12) 0.0298(15) -0.0005(11) 0.0004(13) 0.0005(12)
C2 0.0352(18) 0.0196(12) 0.0366(16) -0.0005(11) 0.0040(14) 0.0003(12)
C3 0.0372(18) 0.0206(12) 0.0280(14) 0.0007(11) -0.0019(13) -0.0006(12)
C4 0.0303(17) 0.0188(13) 0.0366(16) -0.0014(11) -0.0020(14) 0.0000(12)
C5 0.0356(18) 0.0275(14) 0.0301(15) 0.0023(11) 0.0040(14) -0.0004(12)
C6 0.0373(18) 0.0273(14) 0.0289(15) 0.0006(11) -0.0032(14) -0.0001(12)
C7 0.0366(19) 0.0569(19) 0.0429(18) 0.0051(15) -0.0093(15) 0.0008(15)
C8 0.0291(18) 0.0234(13) 0.0345(15) 0.0005(11) 0.0055(13) -0.0001(12)
C9 0.0258(16) 0.0251(13) 0.0335(15) 0.0001(11) -0.0024(13) 0.0003(11)
C10 0.0263(16) 0.0203(12) 0.0312(14) 0.0006(10) 0.0044(13) 0.0000(11)
C11 0.0348(17) 0.0251(14) 0.0294(14) -0.0007(12) 0.0030(13) 0.0061(12)
C12 0.053(3) 0.038(2) 0.201(5) 0.025(3) -0.002(3) -0.0029(18)
C13 0.151(4) 0.0403(18) 0.048(2) 0.0051(16) -0.015(2) 0.029(2)
C14 0.089(3) 0.0270(16) 0.056(2) -0.0053(14) 0.019(2) 0.0049(16)
C15 0.0328(18) 0.0369(15) 0.0414(16) -0.0011(13) 0.0030(14) 0.0028(13)
B1 0.036(2) 0.0153(14) 0.0359(18) -0.0005(13) 0.0045(16) 0.0020(13)

_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
Si2 O4 1.6536(16) . ?
Si2 C14 1.831(3) . ?
Si2 C12 1.834(4) . ?
Si2 C13 1.839(3) . ?
O1 B1 1.368(3) . ?
O1 C8 1.437(3) . ?
O2 B1 1.369(3) . ?
O2 C9 1.437(3) . ?
O3 C4 1.373(3) . ?
O3 C7 1.429(3) . ?
O4 C11 1.433(3) . ?
C1 C2 1.399(3) . ?
C1 C6 1.403(4) . ?
C1 B1 1.558(4) . ?
C2 C3 1.381(3) . ?
C2 H2 0.9500 . ?
C3 C4 1.383(4) . ?
C3 H3 0.9500 . ?
C4 C5 1.396(4) . ?
C5 C6 1.382(4) . ?
C5 H5 0.9500 . ?
C6 H6 0.9500 . ?
C7 H7A 0.9800 . ?
C7 H7B 0.9800 . ?
C7 H7C 0.9800 . ?
C8 C10 1.524(3) . ?
C8 H8A 0.9900 . ?
C8 H8B 0.9900 . ?
C9 C10 1.515(3) . ?
C9 H9A 0.9900 . ?
C9 H9B 0.9900 . ?
C10 C15 1.520(3) . ?
C10 C11 1.529(3) . ?
C11 H11A 0.9900 . ?
C11 H11B 0.9900 . ?
C12 H12A 0.9800 . ?
C12 H12B 0.9800 . ?
C12 H12C 0.9800 . ?
C13 H13A 0.9800 . ?
C13 H13B 0.9800 . ?
C13 H13C 0.9800 . ?
C14 H14A 0.9800 . ?
C14 H14B 0.9800 . ?
C14 H14C 0.9800 . ?
C15 H15A 0.9800 . ?
C15 H15B 0.9800 . ?
C15 H15C 0.9800 . ?

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
O4 Si2 C14 105.35(11) . . ?
O4 Si2 C12 109.61(13) . . ?
C14 Si2 C12 111.57(19) . . ?
O4 Si2 C13 110.18(12) . . ?
C14 Si2 C13 109.43(16) . . ?
C12 Si2 C13 110.6(2) . . ?
B1 O1 C8 119.5(2) . . ?
B1 O2 C9 119.3(2) . . ?
C4 O3 C7 117.5(2) . . ?
C11 O4 Si2 121.90(15) . . ?
C2 C1 C6 116.4(3) . . ?
C2 C1 B1 122.7(2) . . ?
C6 C1 B1 120.8(2) . . ?
C3 C2 C1 122.6(2) . . ?
C3 C2 H2 118.7 . . ?
C1 C2 H2 118.7 . . ?
C2 C3 C4 119.3(2) . . ?
C2 C3 H3 120.3 . . ?
C4 C3 H3 120.3 . . ?
O3 C4 C3 124.9(2) . . ?
O3 C4 C5 115.0(2) . . ?
C3 C4 C5 120.1(3) . . ?
C6 C5 C4 119.5(2) . . ?
C6 C5 H5 120.2 . . ?
C4 C5 H5 120.2 . . ?
C5 C6 C1 122.0(2) . . ?
C5 C6 H6 119.0 . . ?
C1 C6 H6 119.0 . . ?
O3 C7 H7A 109.5 . . ?
O3 C7 H7B 109.5 . . ?
H7A C7 H7B 109.5 . . ?
O3 C7 H7C 109.5 . . ?
H7A C7 H7C 109.5 . . ?
H7B C7 H7C 109.5 . . ?
O1 C8 C10 112.5(2) . . ?
O1 C8 H8A 109.1 . . ?
C10 C8 H8A 109.1 . . ?
O1 C8 H8B 109.1 . . ?
C10 C8 H8B 109.1 . . ?
H8A C8 H8B 107.8 . . ?
O2 C9 C10 112.3(2) . . ?
O2 C9 H9A 109.1 . . ?
C10 C9 H9A 109.1 . . ?
O2 C9 H9B 109.1 . . ?
C10 C9 H9B 109.1 . . ?
H9A C9 H9B 107.9 . . ?
C9 C10 C15 110.1(2) . . ?
C9 C10 C8 107.26(19) . . ?
C15 C10 C8 109.1(2) . . ?
C9 C10 C11 108.1(2) . . ?
C15 C10 C11 110.7(2) . . ?
C8 C10 C11 111.5(2) . . ?
O4 C11 C10 110.8(2) . . ?
O4 C11 H11A 109.5 . . ?
C10 C11 H11A 109.5 . . ?
O4 C11 H11B 109.5 . . ?
C10 C11 H11B 109.5 . . ?
H11A C11 H11B 108.1 . . ?
Si2 C12 H12A 109.5 . . ?
Si2 C12 H12B 109.5 . . ?
H12A C12 H12B 109.5 . . ?
Si2 C12 H12C 109.5 . . ?
H12A C12 H12C 109.5 . . ?
H12B C12 H12C 109.5 . . ?
Si2 C13 H13A 109.5 . . ?
Si2 C13 H13B 109.5 . . ?
H13A C13 H13B 109.5 . . ?
Si2 C13 H13C 109.5 . . ?
H13A C13 H13C 109.5 . . ?
H13B C13 H13C 109.5 . . ?
Si2 C14 H14A 109.5 . . ?
Si2 C14 H14B 109.5 . . ?
H14A C14 H14B 109.5 . . ?
Si2 C14 H14C 109.5 . . ?
H14A C14 H14C 109.5 . . ?
H14B C14 H14C 109.5 . . ?
C10 C15 H15A 109.5 . . ?
C10 C15 H15B 109.5 . . ?
H15A C15 H15B 109.5 . . ?
C10 C15 H15C 109.5 . . ?
H15A C15 H15C 109.5 . . ?
H15B C15 H15C 109.5 . . ?
O1 B1 O2 122.9(3) . . ?
O1 B1 C1 118.6(3) . . ?
O2 B1 C1 118.4(2) . . ?

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
C14 Si2 O4 C11 -169.1(2) . . . . ?
C12 Si2 O4 C11 70.7(2) . . . . ?
C13 Si2 O4 C11 -51.2(2) . . . . ?
C6 C1 C2 C3 0.3(3) . . . . ?
B1 C1 C2 C3 175.5(2) . . . . ?
C1 C2 C3 C4 -1.1(3) . . . . ?
C7 O3 C4 C3 4.5(3) . . . . ?
C7 O3 C4 C5 -175.5(2) . . . . ?
C2 C3 C4 O3 -178.7(2) . . . . ?
C2 C3 C4 C5 1.2(3) . . . . ?
O3 C4 C5 C6 179.4(2) . . . . ?
C3 C4 C5 C6 -0.6(3) . . . . ?
C4 C5 C6 C1 -0.3(4) . . . . ?
C2 C1 C6 C5 0.4(3) . . . . ?
B1 C1 C6 C5 -174.9(2) . . . . ?
B1 O1 C8 C10 26.2(3) . . . . ?
B1 O2 C9 C10 -28.9(3) . . . . ?
O2 C9 C10 C15 173.24(19) . . . . ?
O2 C9 C10 C8 54.6(3) . . . . ?
O2 C9 C10 C11 -65.7(2) . . . . ?
O1 C8 C10 C9 -53.4(3) . . . . ?
O1 C8 C10 C15 -172.6(2) . . . . ?
O1 C8 C10 C11 64.8(3) . . . . ?
Si2 O4 C11 C10 152.56(17) . . . . ?
C9 C10 C11 O4 -176.6(2) . . . . ?
C15 C10 C11 O4 -55.9(3) . . . . ?
C8 C10 C11 O4 65.8(3) . . . . ?
C8 O1 B1 O2 3.0(3) . . . . ?
C8 O1 B1 C1 -172.2(2) . . . . ?
C9 O2 B1 O1 -1.7(3) . . . . ?
C9 O2 B1 C1 173.5(2) . . . . ?
C2 C1 B1 O1 -8.9(3) . . . . ?
C6 C1 B1 O1 166.0(2) . . . . ?
C2 C1 B1 O2 175.7(2) . . . . ?
C6 C1 B1 O2 -9.4(3) . . . . ?

_diffrn_measured_fraction_theta_max 0.994
_diffrn_reflns_theta_full        27.47
_diffrn_measured_fraction_theta_full 0.994
_refine_diff_density_max         0.300
_refine_diff_density_min         -0.306
_refine_diff_density_rms         0.061

_database_code_depnum_ccdc_archive 'CCDC 944020'