##############################################################################
###                                                                        ###
###           Full Paper (Acta Crystallographica Section C)                ###
###                                                                        ###
##############################################################################
#                                                                            #
# This CIF contains the data in a paper accepted for publication in Acta     #
# Crystallographica Section C. It conforms to the editorial and technical    #
# requirements of Notes for Authors for Section C, and has been peer         #
# reviewed under the auspices of the IUCr Commission on Journals.            #
#                                                                            #
# Full details of the Crystallographic Information File format               #
# are given in the paper "The Crystallographic Information File (CIF):       #
# a New Standard Archive File for Crystallography" by S. R. Hall, F. H.      #
# Allen and I. D. Brown [Acta Cryst. (1991), A47, 655-685].                  #
#                                                                            #
# The current version of the core CIF dictionary is obtainable from          #
# ftp://ftp.iucr.org/pub/cif_core.dic. The current version number is 2.0.1.  #
#                                                                            #
# Software is freely available for graphical display of the structure(s) in  #
# this CIF.  For information consult the CIF home page http://www.iucr.org/  #
# cif/home.html                                                              #
#                                                                            #
# This file may be used for bona fide research purposes within the           #
# scientific community so long as proper attribution is given to the journal # 
# article from which it was obtained.                                        #
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##############################################################################
data_global
_audit_creation_method     SHELXL
_journal_date_recd_electronic     97-05-07
_journal_date_accepted     97-10-23
_journal_name_full     'Acta Crystallographica, Section C'
_journal_year     1998
_journal_volume     C54
_journal_issue     APR98
_journal_page_first     462
_journal_page_last     464
_journal_paper_category     FM
_publ_contact_author_name     'Dr. Hongming Zhang'
_publ_contact_author_address
;
      Department of Chemistry
      Southern Methodist University
      Dallas, Texas 75275
      USA
;
_publ_contact_author_email     hzhang@mail.smu.edu
_publ_contact_author_fax     '1 214 768 4089'
_publ_contact_author_phone     '1 214 768 4141'
_publ_section_title
;
2-[(2,5-Dimethoxyphenyl)(ferrocenyl)methyl]-3,6-dimethoxybenzonitrile
;
_publ_section_title_footnote
;
Alternative name:
[1-(2-cyano-3,6,2',5'-tetramethoxybenzhydryl)-η⁵-cyclopentadienyl]-
(η⁵-cyclopentadienyl)iron(II).
;
loop_
    _publ_author_name
    _publ_author_address
    'Zhang, Hongming'
;     Department of Chemistry
      Southern Methodist University
      Dallas, Texas 75275
      USA
;
    'Lu, Yingchun'
;     Department of Chemistry
      Southern Methodist University
      Dallas, Texas 75275
      USA
;
    'Biehl, Ed'
;     Department of Chemistry
      Southern Methodist University
      Dallas, Texas 75275
      USA
;
data_eb-ylfe5
_chemical_name_systematic
;
3,6-Dimethoxy-2-[α-ferrocenyl-α-(2',5'-dimethoxy-
phenyl)]methylbenzonitrile
;
_chemical_name_common     ferrocenylbenzonitrile
_chemical_formula_moiety     ?
_chemical_formula_sum     'C28 H27 Fe N O4'
_chemical_formula_structural     ?
_chemical_formula_analytical     ?
_chemical_formula_iupac     '[Fe (C5 H5) (C23 H22 N1 O4)]'
_chemical_formula_weight     497.36
_chemical_melting_point     ?
_symmetry_cell_setting     orthorhombic
_symmetry_space_group_name_H-M     'P b c a'
loop_
    _symmetry_equiv_pos_as_xyz
    'x, y, z'
    '-x+1/2, -y, z+1/2'
    '-x, y+1/2, -z+1/2'
    'x+1/2, -y+1/2, -z'
    '-x, -y, -z'
    'x-1/2, y, -z-1/2'
    'x, -y-1/2, z-1/2'
    '-x-1/2, y-1/2, z'
_cell_length_a     12.004(2)
_cell_length_b     19.108(2)
_cell_length_c     20.328(2)
_cell_angle_alpha     90.00
_cell_angle_beta     90.00
_cell_angle_gamma     90.00
_cell_volume     4662.7(10)
_cell_formula_units_Z     8
_cell_measurement_reflns_used     25
_cell_measurement_theta_min     10
_cell_measurement_theta_max     15
_cell_measurement_temperature     220(2)
_exptl_crystal_description     plate
_exptl_crystal_colour     orange
_exptl_crystal_size_max     0.35
_exptl_crystal_size_mid     0.25
_exptl_crystal_size_min     0.15
_exptl_crystal_density_diffrn     1.417
_exptl_crystal_density_meas     ?
_exptl_crystal_density_method     'not measured'
_exptl_crystal_F_000     2080
_exptl_absorpt_coefficient_mu     0.68
_exptl_absorpt_correction_type     '\y scan (SHELXTL-Plus; Sheldrick, 1990)'
_exptl_absorpt_correction_T_min     0.77
_exptl_absorpt_correction_T_max     0.88
_exptl_special_details
;
 ?
;
_diffrn_ambient_temperature     220(2)
_diffrn_radiation_type     MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_radiation_source     'fine-focus sealed tube'
_diffrn_radiation_monochromator     graphite
_diffrn_measurement_device     'R3m/V'
_diffrn_measurement_method     'ω/2θ'
_diffrn_reflns_number     4108
_diffrn_reflns_av_R_equivalents     ?
_diffrn_reflns_av_sigmaI/netI     0.0535
_diffrn_reflns_theta_min     2.00
_diffrn_reflns_theta_max     25.01
_diffrn_reflns_limit_h_min     0
_diffrn_reflns_limit_h_max     14
_diffrn_reflns_limit_k_min     0
_diffrn_reflns_limit_k_max     22
_diffrn_reflns_limit_l_min     0
_diffrn_reflns_limit_l_max     24
_diffrn_standards_number     3
_diffrn_standards_interval_count     150
_diffrn_standards_interval_time     ?
_diffrn_standards_decay_%     0
_reflns_number_total     4108
_reflns_number_observed     2794
_reflns_observed_criterion     >4sigma(F)
_refine_ls_structure_factor_coef     Fsqd
_refine_ls_matrix_type     full
_refine_ls_R_factor_all     0.081
_refine_ls_R_factor_obs     0.043
_refine_ls_wR_factor_all     0.102
_refine_ls_wR_factor_obs     0.086
_refine_ls_goodness_of_fit_all     1.02
_refine_ls_goodness_of_fit_obs     1.086
_refine_ls_restrained_S_all     1.044
_refine_ls_restrained_S_obs     1.086
_refine_ls_number_reflns     3674
_refine_ls_number_parameters     307
_refine_ls_number_restraints     0
_refine_ls_hydrogen_treatment     'H atoms riding (C---H 0.96\%A)'
_refine_ls_weighting_scheme
       'calc w = 1/[\s^2^(Fo^2^)+(0.0401P)^2^+1.35P] where P = (Fo^2^+2Fc^2^)/3'
_refine_ls_shift/esd_max     0.000
_refine_ls_shift/esd_mean     0.000
_refine_diff_density_max     0.33
_refine_diff_density_min     -0.26
_refine_ls_extinction_method     none
_refine_ls_extinction_coef     ?
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'
    'Fe' 'Fe' 0.3463 0.8444
                         'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
    'N' 'N' 0.0061 0.0033
                         'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
_computing_data_collection     'R3m/V diffractometer control program'
_computing_cell_refinement     'R3m/V diffractometer control program'
_computing_data_reduction     'R3m/V diffractometer control program'
_computing_structure_solution     'SHELXS86 (Sheldrick, 1990a)'
_computing_structure_refinement     'SHELXL93 (Sheldrick, 1993)'
_computing_molecular_graphics     'SHELXTL-Plus (Sheldrick, 1990b)'
_computing_publication_material     'SHELXL93'
loop_
    _atom_site_label
    _atom_site_fract_x
    _atom_site_fract_y
    _atom_site_fract_z
    _atom_site_U_iso_or_equiv
    _atom_site_thermal_displace_type
    _atom_site_calc_flag
    _atom_site_refinement_flags
    _atom_site_occupancy
    _atom_site_disorder_group
    _atom_site_type_symbol
    Fe 0.21152(4) 0.33481(2) 0.28593(2) 0.02851(13) Uani d . 1 . Fe
    C1 0.2367(2) 0.43008(14) 0.41537(14) 0.0257(7) Uani d . 1 . C
    H1 0.1976(2) 0.46376(14) 0.38724(14) 0.031 Uiso calc R 1 . H
    C11 0.1847(2) 0.4380(2) 0.48395(15) 0.0271(7) Uani d . 1 . C
    C12 0.1628(3) 0.5058(2) 0.5081(2) 0.0324(7) Uani d . 1 . C
    C13 0.1123(3) 0.5146(2) 0.5689(2) 0.0393(8) Uani d . 1 . C
    H13 0.0978(3) 0.5596(2) 0.5843(2) 0.047 Uiso calc R 1 . H
    C14 0.0830(3) 0.4572(2) 0.6070(2) 0.0424(9) Uani d . 1 . C
    H14 0.0496(3) 0.4636(2) 0.6478(2) 0.051 Uiso calc R 1 . H
    C15 0.1037(3) 0.3906(2) 0.5841(2) 0.0361(8) Uani d . 1 . C
    C16 0.1543(3) 0.3812(2) 0.52280(14) 0.0316(7) Uani d . 1 . C
    H16 0.1680(3) 0.3361(2) 0.50768(14) 0.038 Uiso calc R 1 . H
    O12 0.1950(2) 0.56011(11) 0.46787(11) 0.0385(6) Uani d . 1 . O
    C17 0.1675(3) 0.6294(2) 0.4879(2) 0.0460(9) Uani d . 1 . C
    H17A 0.1945(3) 0.6621(2) 0.4558(2) 0.069 Uiso calc R 1 . H
    H17B 0.2014(3) 0.6390(2) 0.5297(2) 0.069 Uiso calc R 1 . H
    H17C 0.0881(3) 0.6337(2) 0.4917(2) 0.069 Uiso calc R 1 . H
    O15 0.0780(2) 0.32975(13) 0.61734(11) 0.0485(6) Uani d . 1 . O
    C18 0.0248(3) 0.3373(2) 0.6798(2) 0.0580(11) Uani d . 1 . C
    H18A 0.0110(3) 0.2919(2) 0.6983(2) 0.087 Uiso calc R 1 . H
    H18B -0.0446(3) 0.3616(2) 0.6743(2) 0.087 Uiso calc R 1 . H
    H18C 0.0722(3) 0.3635(2) 0.7088(2) 0.087 Uiso calc R 1 . H
    C21 0.3587(2) 0.45186(15) 0.41411(14) 0.0246(7) Uani d . 1 . C
    C22 0.4417(3) 0.4172(2) 0.45022(14) 0.0284(7) Uani d . 1 . C
    C23 0.5517(3) 0.4392(2) 0.4471(2) 0.0342(8) Uani d . 1 . C
    H23 0.6058(3) 0.4149(2) 0.4705(2) 0.041 Uiso calc R 1 . H
    C24 0.5826(3) 0.4966(2) 0.4097(2) 0.0363(8) Uani d . 1 . C
    H24 0.6568(3) 0.5106(2) 0.4086(2) 0.044 Uiso calc R 1 . H
    C25 0.5038(3) 0.5331(2) 0.37418(15) 0.0317(7) Uani d . 1 . C
    C26 0.3927(2) 0.5099(2) 0.37653(14) 0.0267(7) Uani d . 1 . C
    O22 0.4066(2) 0.36169(11) 0.48826(10) 0.0356(5) Uani d . 1 . O
    C27 0.4893(3) 0.3139(2) 0.5112(2) 0.0525(10) Uani d . 1 . C
    H27A 0.4545(3) 0.2779(2) 0.5369(2) 0.079 Uiso calc R 1 . H
    H27B 0.5425(3) 0.3385(2) 0.5378(2) 0.079 Uiso calc R 1 . H
    H27C 0.5267(3) 0.2932(2) 0.4742(2) 0.079 Uiso calc R 1 . H
    O25 0.5234(2) 0.59028(12) 0.33563(11) 0.0440(6) Uani d . 1 . O
    C28 0.6339(3) 0.6190(2) 0.3372(2) 0.0511(10) Uani d . 1 . C
    H28A 0.6377(3) 0.6588(2) 0.3084(2) 0.077 Uiso calc R 1 . H
    H28B 0.6863(3) 0.5842(2) 0.3230(2) 0.077 Uiso calc R 1 . H
    H28C 0.6515(3) 0.6334(2) 0.3813(2) 0.077 Uiso calc R 1 . H
    C29 0.3126(3) 0.5482(2) 0.3382(2) 0.0312(7) Uani d . 1 . C
    N30 0.2497(3) 0.57800(15) 0.30596(14) 0.0446(7) Uani d . 1 . N
    C31 0.2158(3) 0.35894(15) 0.38475(13) 0.0265(7) Uani d . 1 . C
    C32 0.1088(3) 0.3343(2) 0.36574(15) 0.0365(8) Uani d . 1 . C
    H32 0.0425(3) 0.3592(2) 0.36960(15) 0.044 Uiso calc R 1 . H
    C33 0.1195(3) 0.2658(2) 0.34001(15) 0.0425(9) Uani d . 1 . C
    H33 0.0618(3) 0.2377(2) 0.32460(15) 0.051 Uiso calc R 1 . H
    C34 0.2332(3) 0.2477(2) 0.34191(15) 0.0406(8) Uani d . 1 . C
    H34 0.2640(3) 0.2058(2) 0.32737(15) 0.049 Uiso calc R 1 . H
    C35 0.2921(3) 0.3044(2) 0.36981(15) 0.0360(8) Uani d . 1 . C
    H35 0.3685(3) 0.3058(2) 0.37720(15) 0.043 Uiso calc R 1 . H
    C36 0.1860(4) 0.4207(2) 0.2282(2) 0.0597(12) Uani d . 1 . C
    H36 0.1509(4) 0.4619(2) 0.2411(2) 0.072 Uiso calc R 1 . H
    C37 0.1335(4) 0.3609(2) 0.2005(2) 0.0627(12) Uani d . 1 . C
    H37 0.0577(4) 0.3559(2) 0.1924(2) 0.075 Uiso calc R 1 . H
    C38 0.2158(4) 0.3105(2) 0.1876(2) 0.0609(12) Uani d . 1 . C
    H38 0.2041(4) 0.2666(2) 0.1691(2) 0.073 Uiso calc R 1 . H
    C39 0.3190(4) 0.3380(2) 0.2076(2) 0.0591(11) Uani d . 1 . C
    H39 0.3875(4) 0.3155(2) 0.2049(2) 0.071 Uiso calc R 1 . H
    C40 0.3000(4) 0.4063(2) 0.2325(2) 0.0615(12) Uani d . 1 . C
    H40 0.3542(4) 0.4364(2) 0.2490(2) 0.074 Uiso calc R 1 . H
_geom_special_details
;
?
;
loop_
    _geom_bond_atom_site_label_1
    _geom_bond_atom_site_label_2
    _geom_bond_site_symmetry_2
    _geom_bond_distance
    _geom_bond_publ_flag
    Fe C31 . 2.062(3) y
    Fe C32 . 2.038(3) y
    Fe C33 . 2.042(3) y
    Fe C34 . 2.034(3) y
    Fe C35 . 2.045(3) y
    Fe C36 . 2.041(4) y
    Fe C37 . 2.034(4) y
    Fe C38 . 2.052(3) y
    Fe C39 . 2.051(3) y
    Fe C40 . 2.043(4) y
    C1 C31 . 1.516(4) y
    C1 C21 . 1.523(4) y
    C1 C11 . 1.535(4) y
    C11 C16 . 1.391(4) y
    C11 C12 . 1.409(4) y
    C12 O12 . 1.376(4) y
    C12 C13 . 1.388(4) y
    C13 C14 . 1.389(5) y
    C14 C15 . 1.377(4) y
    C15 O15 . 1.380(4) y
    C15 C16 . 1.398(4) y
    O12 C17 . 1.424(4) y
    O15 C18 . 1.429(4) y
    C21 C22 . 1.403(4) y
    C21 C26 . 1.408(4) y
    C22 O22 . 1.379(4) y
    C22 C23 . 1.388(4) y
    C23 C24 . 1.385(4) y
    C24 C25 . 1.379(4) y
    C25 O25 . 1.365(4) y
    C25 C26 . 1.406(4) y
    C26 C29 . 1.437(4) y
    O22 C27 . 1.428(4) y
    O22 C35 . 2.981(4) n
    O25 C28 . 1.436(4) y
    C29 N30 . 1.151(4) y
    C31 C35 . 1.420(4) ?
    C31 C32 . 1.422(4) ?
    C32 C33 . 1.416(4) ?
    C33 C34 . 1.408(5) ?
    C34 C35 . 1.413(4) ?
    C36 C40 . 1.399(6) ?
    C36 C37 . 1.421(5) ?
    C37 C38 . 1.403(6) ?
    C38 C39 . 1.406(6) ?
    C39 C40 . 1.417(5) ?
loop_
    _geom_angle_atom_site_label_1
    _geom_angle_atom_site_label_2
    _geom_angle_atom_site_label_3
    _geom_angle_site_symmetry_1
    _geom_angle_site_symmetry_3
    _geom_angle
    _geom_angle_publ_flag
    C34 Fe C37 . . 137.45(15) ?
    C34 Fe C32 . . 68.16(14) ?
    C37 Fe C32 . . 113.7(2) ?
    C34 Fe C36 . . 178.2(2) ?
    C37 Fe C36 . . 40.82(15) ?
    C32 Fe C36 . . 111.7(2) ?
    C34 Fe C33 . . 40.43(14) ?
    C37 Fe C33 . . 111.6(2) ?
    C32 Fe C33 . . 40.62(13) ?
    C36 Fe C33 . . 138.4(2) ?
    C34 Fe C40 . . 141.1(2) ?
    C37 Fe C40 . . 67.8(2) ?
    C32 Fe C40 . . 137.8(2) ?
    C36 Fe C40 . . 40.1(2) ?
    C33 Fe C40 . . 178.2(2) ?
    C34 Fe C35 . . 40.55(12) ?
    C37 Fe C35 . . 177.4(2) ?
    C32 Fe C35 . . 67.74(14) ?
    C36 Fe C35 . . 141.19(15) ?
    C33 Fe C35 . . 67.88(14) ?
    C40 Fe C35 . . 112.8(2) ?
    C34 Fe C39 . . 112.3(2) ?
    C37 Fe C39 . . 67.6(2) ?
    C32 Fe C39 . . 177.70(15) ?
    C36 Fe C39 . . 67.9(2) ?
    C33 Fe C39 . . 141.1(2) ?
    C40 Fe C39 . . 40.5(2) ?
    C35 Fe C39 . . 111.0(2) ?
    C34 Fe C38 . . 110.89(15) ?
    C37 Fe C38 . . 40.2(2) ?
    C32 Fe C38 . . 142.1(2) ?
    C36 Fe C38 . . 68.0(2) ?
    C33 Fe C38 . . 113.06(14) ?
    C40 Fe C38 . . 67.7(2) ?
    C35 Fe C38 . . 137.4(2) ?
    C39 Fe C38 . . 40.1(2) ?
    C34 Fe C31 . . 68.58(12) ?
    C37 Fe C31 . . 142.0(2) ?
    C32 Fe C31 . . 40.59(12) ?
    C36 Fe C31 . . 112.59(13) ?
    C33 Fe C31 . . 68.51(12) ?
    C40 Fe C31 . . 110.81(13) ?
    C35 Fe C31 . . 40.47(11) ?
    C39 Fe C31 . . 137.23(15) ?
    C38 Fe C31 . . 177.1(2) ?
    C31 C1 C21 . . 113.4(2) y
    C31 C1 C11 . . 113.2(2) y
    C21 C1 C11 . . 112.3(2) y
    C16 C11 C12 . . 118.1(3) y
    C16 C11 C1 . . 123.0(3) y
    C12 C11 C1 . . 118.9(3) y
    O12 C12 C13 . . 124.0(3) y
    O12 C12 C11 . . 115.7(3) y
    C13 C12 C11 . . 120.2(3) y
    C12 C13 C14 . . 120.7(3) y
    C15 C14 C13 . . 119.8(3) y
    C14 C15 O15 . . 124.9(3) y
    C14 C15 C16 . . 119.9(3) y
    O15 C15 C16 . . 115.2(3) y
    C11 C16 C15 . . 121.3(3) y
    C12 O12 C17 . . 117.8(3) y
    C15 O15 C18 . . 116.8(3) y
    C22 C21 C26 . . 116.7(3) y
    C22 C21 C1 . . 123.0(3) y
    C26 C21 C1 . . 120.2(3) y
    O22 C22 C23 . . 123.3(3) y
    O22 C22 C21 . . 116.1(3) y
    C23 C22 C21 . . 120.6(3) y
    C24 C23 C22 . . 121.3(3) y
    C25 C24 C23 . . 120.3(3) y
    O25 C25 C24 . . 126.0(3) y
    O25 C25 C26 . . 115.8(3) y
    C24 C25 C26 . . 118.2(3) y
    C25 C26 C21 . . 122.8(3) y
    C25 C26 C29 . . 117.1(3) y
    C21 C26 C29 . . 120.0(3) y
    C22 O22 C27 . . 117.6(3) y
    C22 O22 C35 . . 88.3(2) n
    C27 O22 C35 . . 110.5(2) n
    C25 O25 C28 . . 116.9(3) y
    N30 C29 C26 . . 178.1(3) y
    C35 C31 C32 . . 106.4(3) ?
    C35 C31 C1 . . 129.8(3) ?
    C32 C31 C1 . . 123.9(3) ?
    C35 C31 Fe . . 69.1(2) ?
    C32 C31 Fe . . 68.8(2) ?
    C1 C31 Fe . . 127.2(2) ?
    C33 C32 C31 . . 108.9(3) ?
    C33 C32 Fe . . 69.8(2) ?
    C31 C32 Fe . . 70.6(2) ?
    C34 C33 C32 . . 107.8(3) ?
    C34 C33 Fe . . 69.5(2) ?
    C32 C33 Fe . . 69.5(2) ?
    C33 C34 C35 . . 107.9(3) ?
    C33 C34 Fe . . 70.1(2) ?
    C35 C34 Fe . . 70.2(2) ?
    C34 C35 C31 . . 109.0(3) ?
    C34 C35 Fe . . 69.3(2) ?
    C31 C35 Fe . . 70.4(2) ?
    C34 C35 O22 . . 146.8(2) ?
    C31 C35 O22 . . 81.7(2) ?
    Fe C35 O22 . . 141.93(14) ?
    C40 C36 C37 . . 107.4(4) ?
    C40 C36 Fe . . 70.0(2) ?
    C37 C36 Fe . . 69.3(2) ?
    C38 C37 C36 . . 108.3(4) ?
    C38 C37 Fe . . 70.6(2) ?
    C36 C37 Fe . . 69.8(2) ?
    C37 C38 C39 . . 108.1(4) ?
    C37 C38 Fe . . 69.2(2) ?
    C39 C38 Fe . . 69.9(2) ?
    C38 C39 C40 . . 107.8(4) ?
    C38 C39 Fe . . 70.0(2) ?
    C40 C39 Fe . . 69.4(2) ?
    C36 C40 C39 . . 108.4(4) ?
    C36 C40 Fe . . 69.9(2) ?
    C39 C40 Fe . . 70.1(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_site_symmetry_1
    _geom_torsion_site_symmetry_2
    _geom_torsion_site_symmetry_3
    _geom_torsion_site_symmetry_4
    _geom_torsion
    _geom_torsion_publ_flag
    C1 C11 C12 O12 . . . . -2.6(4) ?
    C1 C21 C22 O22 . . . . -0.6(4) ?
    C1 C21 C26 C29 . . . . -1.2(4) ?
    C17 O12 O15 C18 . . . . -3.9(3) ?
    C27 O22 O25 C28 . . . . -23.3(3) ?
