Anhydrides of real and hypothetical [hydroxy(R-O)iodo]benzenes

Article abstract of DOI:10.1021/ic1007318

The anhydrides of [hydroxy(methanesulfonato-O)]iodobenzene (HMIB) and [hydroxy(toluenesulfonato-O)]iodobenzene (HTIB) were prepared by drying acetonitrile solutions of the compounds. The anhydrides of the hypothetical compounds [hydroxy(chloroacetato)-O]iodobenzene and [hydroxy(iodoacetato)-O] iodobenzene were obtained from aqueous solutions. Crystallographic structures were obtained for the anhydrides, except that of HTIB. The electron-domain geometries of the I atoms vis-a-vis secondary I...O bonds were explored. The presence of delocalized bonding in groupings of O and I atoms was suggested. A linear relationship between the C-I-O angles and the I-O bond orders was observed.

Full text of DOI:10.1021/ic1007318

Inorg. Chem. 2010, 49, 5413–5423 5413
DOI: 10.1021/ic1007318
Anhydrides of Real and Hypothetical [Hydroxy(R-O)iodo]benzenes
Helen W. Richter,*,† Noel M. Paul,†,‡ Dale G. Ray,† Charlotte A. Ray,† Louise M. Liable-Sands,§ Tom Concolino,§
Matthew Lam,§ Arnold L. Rheingold,^ Gerald F. Koser,† and James A. Golenz
†Department of Chemistry, The University of Akron, Akron, Ohio 44325-3601, §Department of Chemistry and
Biochemistry, University of Delaware, 102 Brown Lab, Newark, Delaware 19716, ^Department of Chemistry
and Biochemistry, University of California, San Diego, 9500 Gilman Drive, m/c 0358, Urey Hall 5128, La Jolla,
z
California 92093-0358, and Department of Chemistry and Biochemistry, University of Massachusetts at
‡
Dartmouth, North Dartmouth, Massachusetts 02747. Remington Products Fellow, Summer 1997.
Received December 3, 2009
The anhydrides of [hydroxy(methanesulfonato-O)]iodobenzene (HMIB) and [hydroxy(toluenesulfonato-O)]iodo-
benzene (HTIB) were prepared by drying acetonitrile solutions of the compounds. The anhydrides of the hypothetical
compounds [hydroxy(chloroacetato)-O]iodobenzene and [hydroxy(iodoacetato)-O]iodobenzene were obtained
from aqueous solutions. Crystallographic structures were obtained for the anhydrides, except that of HTIB. The
ꢀ
electron-domain geometries of the I atoms vis-a-vis secondary I O bonds were explored. The presence of deloca-
3 3 3
lized bonding in groupings of O and I atoms was suggested. A linear relationship between the C-I-O angles and the
I-O bond orders was observed.
Introduction
It is easy to visualize formation of the anhydrides of [hydroxy-
(R-O)iodo]benzenes:
Aryl λ3-iodanes (1) can support a variety of O-centered
ligands such as water molecules, hydroxide ions, alkyl
and aryl sulfonate ions, and carboxylate ions.1-3 The
asymmetric species [hydroxy(methanesulfonato-O)iodo]-
benzene (HMIB, 2)2 and [hydroxy(toluenesulfonato-O)-
iodo]benzene (HTIB, 3) are useful synthetic reagents.4,5
The nature of the bonding in these compounds has been
examined.6
Several of these μ-oxodiiodanes (4) have been isolated
(L1 and L2 defined in structures 1 and 4). In 1972,
Merkushev and co-workers reported the preparation of
μ-oxobis[trichloroacetato-O(phenyl)iodine(III)],7 μ-oxobis-
[chloroacetato-O(phenyl)iodine(III)],7 and μ-oxobis[bromo-
acetato-O(phenyl)iodine(III)] with characterization via
elemental analysis and molecular weight determinations.
Structures have been determined via X-ray crystallography
for μ-oxobis[nitrato-O(phenyl)iodine(III)],8 μ-oxobis[trifluoro-
acetato-O(phenyl)iodine(III)],9 μ-oxobis[trifluoroacetato-
O(m-methylphenyl)iodine(III)],10 μ-oxo[nitrato-O(phenyl)-
iodine(III)][phenyl(trifluoroacetato-O)iodine(III)],11 and the
(6) Koser, G. F. Hypervalent halogen compounds. In The Chemistry of
Functional Groups, Supplement D; Patai, S., Rappoport, Z., Eds.; Wiley:
Chichester, U.K., 1983; Chapter 18; pp 734-740.
(7) Merkushev, A. N.; Novikov, A. N.; Kogai, T. I.; Glushkova, V. V. Zh.
Org. Khim. 1972, 8, 436.
(8) Alcock, N. W.; Countryman, R. M. J. Chem. Soc., Dalton Trans. 1979,
851–853.
*To whom correspondence should be addressed. E-mail: richter@uakron.edu.
Telephone: 330/972-6062.
(1) Ochiai, M.; Miyamoto, K.; Yokota, Y.; Suefuji, T.; Shiro, M. Angew.
Chem., Int. Ed. 2005, 44, 75–78.
(2) Richter, H. W.; Cherry, B. R.; Zook, T. Z.; Koser, G. F. J. Am. Chem.
Soc. 1997, 119, 9614–9623.
(3) Richter, H. W.; Koser, G. F.; Incarvito, C. D.; Rheingold, A. L. Inorg.
Chem. 2007, 46, 5555–5561.
(4) Koser, G. F.; Wettach, R. H. J. Org. Chem. 1980, 45, 4988–
4989.
(9) Gallos, J.; Varvoglis, A.; Alcock, H. W. J. Chem. Soc., Perkin Trans. 1
1985, 757–764.
(10) Kokkou, S. C.; Cheer, C. J. Acta Crystallogr., Sect. C 1986, C42,
1748–1750.
(5) Koser, G. F.; Wettach, R. H.; Troup, J. M.; Frenz, B. A. J. Org. Chem.
1976, 41, 3609–3611.
(11) Bushnell, G. W.; Fischer, A.; Ibrahim, P. N. J. Chem. Soc., Perkin
Trans. 2 1988, 1281–1285.
r
2010 American Chemical Society
Published on Web 05/20/2010
pubs.acs.org/IC

5414 Inorganic Chemistry, Vol. 49, No. 12, 2010
Richter et al.
Figure 1. Structures of the reported compounds. The thermal ellipsoids are at 50% probability, generated by Mercury 2.2.
Table 1. Selected Bond Distances and Bond Angles in HMIB and HTIB
diacetato μ-oxodiiodane where the I atoms have a bridging
binaphthyl group.12 Most recently, Nemykin et al.13 have
isolated μ-oxobis[acetato-O(phenyl)iodine(III)]. Though
formally anhydrides of [hydroxy(X-O)iodo]benzenes, these
μ-oxodiiodanes were not obtained from the parent com-
pounds.
˚
bond distance (A)
bond angle (deg)
atoms
HMIB
HTIBa
atoms
HMIB
HTIBa
I1-O1
I1-O2
I1-C1
H1-O1
1.948(2)
2.502(3)
2.107(3)
0.809
3.388
2.820
1.940 O1-I1-O2
2.474 C1-I1-O1
2.083 C1-I1-O2
0.729 C1-I1-O3
3.535 C1-I1-O30
172.96(8) 178.75
92.18(11) 92.08
81.38(10) 85.96
117.69
In this paper, we report thepreparation of four anhydrides.
μ-Oxobis[methanesulfonato-O(phenyl)iodine(III)] (HMIBA,
5) and μ-oxobis[toluenesulfonato-O(phenyl)iodine(III)]
(HTIBA, 6) were obtained from dried CH3CN solutions; the
structure of HMIBA was determined by single-crystal X-ray
crystallography. The anhydrides of [hydroxy(chloroacetato-
O)iodo]benzene and [hydroxy(iodoacetato-O)iodo]benzene,
both hypothetical compounds that have not been isolated,
were obtained from aqueous solutions of HMIB to which
the corresponding haloacetate was added; the crystal struc-
tures of both μ-oxobis[chloroacetato-O(phenyl)iodine(III)]
(HCIBA, 7) and μ-oxobis[iodoacetato-O(phenyl)iodine(III)]
(HIIBA, 8) were obtained. The structure of HMIB was deter-
mined; the structure of HTIB has been reported previously5
and is discussed relative to the present compounds. The electron-
domain geometry (EDG) of the I atoms in these aryl λ3-iodanes
and μ-oxodiiodanes is presented along with those of com-
pounds in the literature, showing the wide range of coordi-
nation geometries assumed by iodine. The bond order of
I-O bonds is evaluated relative to structural features in the
compounds.
I1 O3
171.05
175.09
3 3 3
I1 O30
C4 C1-I1
177.68
166.87
98.09
3 3 3
3 3 3
I1 O40
I1 S1
4.040
3.504(8)
O1-H1 O40 167.73
3 3 3
3 3 3
I1-O1-H1
106.5
120.6(2)
3 3 3
H1 O40 1.860
1.940 I1-O2-S1
127.27
3 3 3
O3 O30 3.646
O3 I1 O30 71.26
3 3 3
3 3 3 3 3 3
I1 O3 I10 108.74
3 3 3
3 3 3
a Values for HTIB taken from ref 5.
acetonitrile solutions of HTIB was indicated by the produc-
tion of a compound that was soluble in chloroform; like HMIB,
HTIB does dissolve in this solvent. In contrast to the sharp
melting points (with decomposition) for HMIBA and HTIBA,
both HCIBA and HIIBA showed complex thermal behavior,
giving first a transition from a crystalline solid to a waxy clump,
followed by melting with decomposition at higher tempera-
tures (HCIBA 100/158-162 ꢀC; HIIBA 99/112-113 ꢀC).
The HCIBA reported by Merkushev and co-workers7 had a
melting point of 113.5-115 ꢀC, which disagrees with the com-
pound reported here.
Structure of HMIB. HMIB shows the nearly linear
O-I-O segment characteristic of aryl λ3-iodanes; the
unsymmetrically polarized nature of the triad in this
compound is reflected in the large difference in the I-O
bond distances, a result of the greater basicity of HO-
compared to MsO- (Figure 1 and Table 1). The atoms in
the T-shaped bond (C1, I1, O1, and O2) are virtually co-
Results
A remarkable feature of HMIBA is that it is soluble in dry,
stabilizer-free chloroform, in contrast to HMIB, which is
quite insoluble in this solvent. The isolation of HTIBA from
˚
(12) Ochiai, M.; Sueda, T.; Miyamoto, K.; Kiprof, P.; Zhdankin, V. V.
Angew. Chem., Int. Ed. 2006, 45, 8203–8206. Ochiai, M.; Takaoka, Y.; Masaki,
Y.; Nagao, Y.; Shiro, M. J. Am. Chem. Soc. 1990, 5677–5678.
(13) Nemykin, V. N.; Koposov, A. Y.; Netzel, B. C.; Yusubov, M. S.;
Zhdankin, V. V. Inorg. Chem. 2009, 48, 4908–4917.
planar, with an average atomic displacement of 0.020(12) A.
The C-I-O angles exhibit a “droop-and-shrug” motif,
wherein the more basic hydroxide pushes away the
phenyl ring, giving an angle greater than 90ꢀ so that

Article
Inorganic Chemistry, Vol. 49, No. 12, 2010 5415
˚
methanesulfonate has an angle less than 90ꢀ. The plane of
the phenyl ring is nearly normal to the T-shaped bond
plane (83.3ꢀ between planes). The O-H bond distance in
tion (I1 O13, 3.622 A). Dimers form when Oii-I2-O2
3 3 3
segments from two molecules align, held together by three
˚
pairs of I O bonds [I1 O220 and I10
O22, 3.361(6) A;
3 3 3
3 3 3
3 3 3
˚
˚
the hydroxide ligand is 0.809(1) A, where the sum of the
I1 O230 and I10
O23, 3.089(7) A; I2 O230 and
3 3 3 3 3 3
˚
03 3 3
˚
covalent radii is 1.10 A, showing the robust nature of the
ligand.
I2
O23, 3.3672(5) A; Figure 2].
3 3 3
Secondary bonds are important in the solid-state struc-
ture of HMIB (Figures 2 and 3 and Table 1). The I atom
has a weak intramolecular interaction with an O atom
in the MsO- ligand. Dimers form when two O-I-O seg-
ments assume an antiparallel alignment, stabilized by a
pair of very strong intermolecular I O bonds (I1 O30
Structure of HCIBA. The structure of HCIBA parallels
that of HMIBA (Figures 1 and 2 and Table 2). The O-
I-O segments are slightly bent, and the droop-and-shrug
motif in the C-I-O angles becomes a “straight-and-
shrug” motif, where the bonds to the bridging O atom
give nearly normal angles but the bonds to methanesul-
fonate are 10ꢀ smaller. Both I1 and I2 have strong
3 3 3
3 3 3
and I10
O3, 2.820 A). Pairs of dimers align with O-
˚
3 3 3
I-O segments end-to-end and offset, producing a stair-
like structure where “risers” are produced when the dimer
steps are joined by hydrogen bonds between the H atoms
in the hydroxides and the O atoms in the0methanesulfo-
nate ligands (H1 O4A and H1A0
intramolecular I O bonds. An antiparallel alignment
˚
O4 , 1.860 A) and
3 3 3
3 3 3
3 3 3
0
by weak I O bonds (I1 O4A and I1A0
The hydrogen bonds are strong, well below the van der
O4 , 3.505A).
of the Oii-I1-O1 segments in two HCIBA molecules
˚
3 3 3
3 3 3
3 3 3
produces a dimer by virtue of two intermolecular I
˚
O
O12, 3.020(1) A]. The dimers
3 3 3
bonds [I1 O120 and I10
stack in a stairlike array, with no I O bonds between
˚
Waals (vdw) sum of 2.50 A.
3 3 3
3 3 3
Structure of HTIB. The structure of HTIB (3) was deter-
mined in 1976 (Table 1),5 and it mirrors that of HMIB.
While the O-I-O segment in HTIB is virtually linear, the
same droop-and-shrug motif in the C-I-O angles appears.
The plane of the T-shaped bond is virtually planar; no atom
3 3 3
them. However, the segment containing I2 dangles from
one of the Oii vertices of the O-I-O-O-I-O hexagon
and places H27 directly above the hexagon in dimer A
(Figures 3 and 4); the chloromethyl group rotates so that
H27 points to the center of the hexagon, forming a
˚
is displaced by more than 0.001 A from the plane. The intra-
molecular I1 O3 bond approaches the vdw limit. Dimers
˚
rectangular pyramid with H27 at the apex, 2.183 A above
0
3 3 3
0
˚
form when two O-I-O segments assume an antiparallel
alignment and are held in position by hydrogen bonds
plane Oii-O1-Oii -O1 (distances from H27: Oii, 4.155 A;
O1, 4.010 A; Oii , 4.647 A; O1 , 3.634 A).
0
0
˚
˚
˚
0
(H1 O3A0 and O3 H1A , 2.004 A; Figure 2). Pairs of
Structure of HIIBA. The preparation of HIIBA yielded
two crystallographically different forms with similar bond
distances and angles (Table 2); only one form is discussed
here. As in HCIBA, the O-I-O segments are slightly
bent. Likewise, the C-I-O angles have a straight-and-
shrug motif where the bonds to oxide give nearly normal
angles but the bonds with the iodoacetate are 10ꢀ smaller.
An antiparallel alignment of Oii-I2-O2 segments in two
˚
3 3 3
3 3 3
dimers with O-I-O segments aligned in an opposite sense
produce a stairlike structure stabilized by hydrogen bonds,
much like that in HMIB.
HIIBA molecules produces a dimer held together by two
˚
pairs of I O bonds (I2 O220 and I20
O22, 3.004 A;
O22, 3.217 A; Figure 2). The dimer
303 3
is further stabilized by strong intramolecular I O bonds
3 3 3
3 3 3
I1 O22 and I10
˚
3 3 3
3 3 3
3 03 3
for both I1 and I2 (I1 O12 and I10
O12 , 2.993 A;
˚
3 3 03
3 3 3
I2 O22 and I20
O22 , 3.058 A).
˚
3 3 3
3 3 3
O-C-O-O-C-O Hexagons. In the reported com-
pounds and in HTIB, dimers form when O-I-O seg-
ments from two molecules assume an antiparallel align-
ment. These dimers contain a hexagonal grouping with a
flat “seat” formed by A-B-A0-B0 and triangular “flaps”
formed by A-C-B and A0-C0-B0 (Figure 4 and Table 3).
The seats are parallelograms; in all cases, a chair con-
formation is adopted with flap/seat angles from 2ꢀ to 84ꢀ.
In the worst case (HIIBA), the I atoms are displaced from
Structure of HMIBA. The methanesulfonate ligands in
this μ-oxo-λ3-iodane are robust, with the expected tetra-
hedral geometry about the S atoms (Figure 1 and Table
2). Each molecule has two nearly linear O-I-O bond
segments, and each segment is unsymmetrically polari-
zed; the interior I1-Oii and I2-Oii bond lengths are
“short”, while I1-O1 and I2-O2 are “long”. The ligands
on I1 are methanesulfonate and the conjugate base of
HMIB (9); the bond lengths indicate that 9 is more basic
than methanesulfonate, which should have a negligible
base strength. The droop-and-shrug motif in the C-I-O
angles appears with the phenyl ring slightly tilted away
from the I-9 bond and slightly toward the I-methane-
sulfonate bond. I2 has a good intramolecular secondary bond
˚
the planar seat by only 0.077 A. In addition, each dimer
contains a flat “diamond” structure (I-D-I0-D0)
formed by I O bonds, where D and D0 are tethered to
3 3 3
the seat, one above and one below the plane. The seat and
diamond are not coplanar: the angle between the planes
ranges from 7ꢀ to 42ꢀ. Perhaps delocalized bonding arises
in the four-atom “diamond” grouping (I-D-I0-D0) that
might stabilize the hexagonal groupings.
EDG of the I Atoms in HMIB and HTIB. The I atom
in HMIB is CN 7 owing to three primary bonds, two
˚
(I2 O23, 3.165 A), but I1 has only a marginal interac-
3 3 3

5416 Inorganic Chemistry, Vol. 49, No. 12, 2010
Richter et al.
Figure 2. Structures of dimers of the reported compounds and HTIB. The green lines denote secondary bonds, and the light-gray line indicates the
hexagonal structure. H atoms are omitted in some structures. Structures are generated by Mercury 2.2 and annotated using ArcSoft PhotoStudio 5.5.0.72.
Figure 3. Packing of dimers into stair structures for HMIB and HCIBA. H atoms are omitted. Green lines signify secondary bonds. Gray lines serve to
clarify structures. Structures are generated by Mercury 2.2 and annotated using ArcSoft PhotoStudio 5.5.0.72.
unshared pairs of electrons, an intramolecular bond
˚
(I1 O3, 3.388 A), and a strong intermolecular bond
where O3 is the capping atom and the unshared pairs
are assigned to the axial vertices (Figure 5). The equatorial
plane defined by C1, I1, O1, O2, and O30 is excellent, with
3 3 3
0
˚
(I1 O3 , 2.820 A). The EDG is capped octahedral,
3 3 3

Article
Inorganic Chemistry, Vol. 49, No. 12, 2010 5417
0
˚
I1 O22 , 3.361(1) A] for CN 7 and pentagonal-bipyr-
3 3 3
amidal EDG (Figure 5). The pentagonal plane contains
C11, O230, and O220 and the two unshared pairs; I1 is
˚
0.022 A out of this plane. The axial positions are occupied
by Oii and O1, where the nearly linear axis [173.7(2)ꢀ] is
slightly tipped. I2 is CN 8, with one intramolecular bond
˚
[I2 O23, 3.1650(1) A], one bond with its dimer partner
3 3 3
0
˚
[I2 O23 , 3.367(7) A], and one bond with a neighboring
3 3 3
0
˚
dimer [I2 OiiA , 3.372(6) A]. The EDG is best des-
3 3 3
cribed as triangular dodecahedral,14 with the vertices
occupied by C21, Oii, O2, O23, O230, and OiiA0 and
the two unshared pairs, with I2 at the center. Atoms
Oii, C21, O2, and O23 are in a plane with an average
˚
˚
atomic displacement of 0.094(25) A; I2 is 0.411 A out of
the plane.
EDG of the I Atoms in HCIBA. Both I atoms in HCIBA
Figure 4. Structures of the O-C-O-O-C-O hexagons where solid
black lines denote primary bonds, green lines denote secondary I
O
are CN 7. I1 has an intramolecular bond [I1 O12,
˚
2.971(7) A] and one bond with its dimer partner [I1
3 3 3
3 3 3
bonds, blue lines denote hydrogen-bonding interactions, and brown lines
outline the hexagon: (a) general labeling used for Table 3; (b) structure of
the hexagon in HCIBA showing the position of H27 above the seat of the
hexagonal grouping of a neighboring dimer.
3 3 3
0
˚
O12 , 3.020(1) A], giving pentagonal-bipyramidal EDG.
In contrast to I1 in HMIBA, all five pentagonal vertices
are occupied by atoms, while the unshared pairs occupy
the axial positions (Figure 5). The plane is lightly puck-
Table 2. Structures of μ-Oxo Dimers
˚
ered, with an average atomic displacement of 0.088(49) A;
atom/segment
HMIBA
HCIBA
˚
HIIBA
HIIBA0
˚
I1 is displaced by 0.012 A. The pentagonal angles app-
roach the ideal value of 72ꢀ, where O1-I1-O12 is con-
strained to a small value by the tether to C1. I2 has one
Bond Distances (A)
Oii-I1
2.022(6)
2.315(6)
2.083(8)
1.502
2.009(6)
2.342(6)
2.098(8)
1.502
2.048
2.270
2.102
1.292
2.027
2.234
2.099
1.280
2.042
2.251
2.104
1.281
2.040
2.261
2.104
1.315
2.036
2.256
2.130
1.308
2.045
2.237
2.106
1.300
˚
intramolecular bond [I2 O22, 3.072(1) A] and one very
3 3 3
I1-O1
0
˚
weak bond with its dimer partner [I2 O12 , 3.534(7) A].
I1-C11
O1-(S1 or C1)
Oii-I2
I2-O2
I2-C21
O2-(S2 or C2)
3 3 3
The EDG is best described as capped octahedral, with the
unshared pairs assigned to the axial positions and O120 as
˚
the capping atom (Figure 5); O12 lies 2.096 A from the
0
square plane (Oii-C21-O2-O22). The ideal 90ꢀ angles
are not realized all around because O2-I2 O22 is con-
strained to a smaller angle by the tether to C2, and the
3 3 3
Bond Angles (deg)
capping atom opens angle Oii-I2 O22.
Oii-I1-O1
173.7(3)
94.7(3)
79.0(3)
174.14
126.2(3)
117.7(3)
172.4(2)
92.5(3)
79.9(2)
177.66
167.73
88.23
79.51
176.16
108.92
122.21
168.25
90.58
169.93
89.91
80.03
176.59
111.20
117.64
166.10
88.23
169.10
89.56
79.60
177.03
110.54
116.33
166.58
88.69
3 3 3
C11-I1-Oii
C11-I1-O1
I1-C11-C14
I1-O1-(S1 or C1)
I1-Oii-I2
EDG of the I Atoms in HIIBA. HIIBA has four I atoms
per molecule; I1 and I2 participate in three-center four-
electron [3c-4e] bonds, while I12 and I22 have ordinary
covalent bonds. I1 is CN 7, with one intramolecular
˚
Oii-I2-O2
bond [I1 O12, 2.989(1) A] and one bond with its
0
3 3 3
C21-I2-Oii
C21-I2-O2
I2-C21-C24
I2-O2-(S2 or C2)
˚
dimer partner [I1 O22 , 3.217(6) A]. The EDG is best
3 3 3
80.71
175.91
113.24
78.46
178.82
113.39
77.95
177.85
112.96
described as capped octahedral, where the unshared
pairs occupy the axial vertices and O220 is the capping
atom (Figure 5). The average atomic displacement from
115.0(3)
Angle of Segment w/I1-Oii-I2 Plane (deg)
˚
the square plane (C12-Oii-O12-O1) is 0.031(11) A,
and I1 is only 0.043 A out of the plane. I2 is CN 7, with
˚
I1-C11
I2-C21
67.8
80.3
54.8
85.7
84.4
71.5
83.4
60.2
˚
one intramolecular bond [I2 O22, 3.089(1) A] and
3 3 3
one bond with its dimer partner [12 O220, 3.004(7)
Angle of Segment w/Average Phenyl Plane (deg)
3 3 3
˚
A]; the EDG is pentagonal bipyramidal, with the un-
I1-Oii
I2-Oii
74.6
64.4
73.7
69.6
46.9
90.0
48.5
71.4
shared pairs in the axial positions. The pentagonal
plane is puckered with an average atomic displacement
˚
˚
˚
of 0.209(74) A; I2 is displaced by only 0.040 A. The
an average atomic displacement of 0.034(22) A. The I
atom in HTIB is CN 8 owing to an intramolecular bond
pentagonal angles approach the ideal 72ꢀ, where O2-
˚
(I1 O3, 3.535 A) and two intermolecular bonds
I2 O22 is small because of tethering. I12 and I22 are
in the haloacetate ligands; I12 has no secondary bonds
and exhibits bond distances and angles expected for I
3 3 3
3 3 3
0
0
˚
˚
(I1 O4 , 3.003 A; I1 O2 , 3.351 A). Atoms O1, C1,
3 3 3
3 3 3
O2, and O20 give a plane with average atomic displace-
sp3.15 In contrast, I22 is the I atom in the I O bond
˚
˚
ment of 0.032(6) A; I1 is only 0.033 A from the plane.
Atoms O3 and O40 complete a hexagon, giving a hexa-
gonal bonding-domain geometry in a chair conformation.
The placement of the unshared electron pairs, as in Figure 5,
produces a triangular dodecahedral EDG.
3 3 3
˚
[I22 OiiB, 3.017(6) A] that makes dimers (Figure 3)
3 3 3
(14) Wells, A. F. Structural Inorganic Chemistry, 5th ed.; Clarendon Press:
Oxford, U.K., 1984.
(15) March, J. Advanced Organic Chemistry, 4th ed.; John Wiley and Sons:
New York, 1992.
EDG of the I Atoms in HMIBA. I1 has two intermole-
0
˚
cular bonds with its dimer partner [I1 O23 , 3.089(1) A;
3 3 3

5418 Inorganic Chemistry, Vol. 49, No. 12, 2010
Richter et al.
Table 3. Atomic Distances and Angles in the Hexagon and Diamond Structuresa
˚
distance (A)
angle (deg)
A-B-A0
I, A, B, D
I-0
D-0
I-D
I-D0
Δ-0
)-0
D-I-D0
HTIB
HMIB
HMIBA
HCIBA
HIIBA
34
21
23
35
I1, O1, O2, O3
I1, O1, O2, O3
I2, Oii, O2, O23
I1, Oii, O1, O12
I2, Oii, O2, O22
I1, O1, O3, O4
I1, O1, O3, O4
I2, O7, O5, O4
I2, O1, O2, O3
0.024
0.021
0.049
0.000
0.077
0.093
0.037
0.016
0.053
1.179
0.876
1.541
0.201
0.467
0.379
0.050
0.094
0.936
3.535
3.388
3.165
2.971
3.089
3.000
2.935
3.020
3.124
3.564
2.820
3.367
3.020
3.004
3.038
2.936
3.096
3.623
83.53
16.8
26.7
2.37
1.82
4.21
9.19
0.00
35.56
25.48
29.44
42.04
7.28
13.88
12.53
1.94
86.13
104.12
99.48
101.75
98.12
101.24
101.89
98.52
101.12
71.26
89.60
64.13
79.93
71.87
68.87
74.20
91.22
2.96
22.87
91.23
a Refer to Figure 4 for atom labeling. 0 denotes the seat of the hexagon, A-B-A0-B0; Δ denotes the flap on the hexagon, A-C-B; ) denotes the
diamond, I-D-I0-D0.
Figure 5. EDGs of the I atoms in the reported compounds and HTIB. Black lines denote primary bonds, green lines denote secondary bonds, bright-blue
wedges denote unshared electron pairs, and orange/brown lines serve to visualize geometric structures. Secondary bonds in HTIB and HMIBA(I2) are not
shown. The figures were prepared using MDL ISIS/Draw 2.5 from structures generated by Mercury 2.2.
so that it is CN 5. The molecular geometry is nearly
linear (—C27-I22 OiiB, 170.58ꢀ), and the EDG is
(this species can be solvated with additional CD3OD
molecules):
3 3 3
trigonal-bipyramidal.
NMR Spectroscopy. The 1H NMR spectra of CD3OD
solutions of HMIB, HMIBA, HTIB and HTIBA are
virtually identical (Table 4), consistent with solvolysis of
each compound to PhI(OCD3)2 and CH3SO3D. [Dimethoxy-
(iodo)]benzene has been isolated,16 though it is unstable
probably because of the unfavorable influence of two
strong trans-influencing ligands on IIII.12 Consequently,
the species in these acidic methanolic solutions is more
likely the protonated form that circumvents this problem
In contrast, the aromatic δ for HCIBA and HIIBA are
significantly shifted, suggesting that the haloacetate ligands
successfully compete with methoxide in methanol solu-
tions. Spectra of HMIBA and HTIBA in a CDCl3 solution
were obtained. In the driest HMIBA solutions prepa-
red, the o-1H appeared as a doublet with no fine structure;
both the p- and m-1H presented as triplets of triplets. The
(16) Schardt, B. C.; Hill, C. L. Inorg. Chem. 1983, 22, 1563–1565.

Article
Inorganic Chemistry, Vol. 49, No. 12, 2010 5419
Table 4. Chemical Shifts in the 1H NMR Spectra of CD3OD and CDCl3 Solutionsa
EDG with atoms in the axial positions. The one lone
pair resides in the equatorial plane. The phenyl C atom
and an O atom from the intermolecular bond form the
1H NMR chemical shifts (ppm)
nearly linear axis (—C1-I1 O20, 168.2ꢀ). Other CN 6
sample
o-PhI
p-PhI
m-PhI
CH3- or XCH2-
3 3 3
species with octahedral EDG17 include [dichloro(iodo)]-
trifluoromethane (13),20 [dichloro(iodo)]benzene (14),21
1-(tert-butylsulfonyl)-2-iodosylbenzene (15),22 [dichloro-
(iodo)]-2,4,6-triisopropylbenzene (16),23 and 1-dichloro-
iodo-2,6-bis(3,5-dichloro-2,4,6-trimethylphenyl)benzene
(17).24
CD3OD Solutions
HMIB
HMIBA
HTIB
HTIBA
HCIBA
HIIBA
8.38
8.38
8.35
8.35
8.12
8.11
7.86
7.86
7.83
7.84
7.65
7.64
7.72
7.72
7.69
7.70
7.57
7.57
2.69
2.68
2.38
2.37
4.00
3.61
The pentagonal-bipyramidal EDG shown by three of
the present CN 7 I atoms is favored by iodine in seve-
-
CDCl3 Solutions
ral oxidation states. The I-centered IOF6 anion (18;
Figure 6)25 has oxide and fluoride in the axial vertices.
The pentagonal equatorial plane is puckered with O-
I-Feq angles from 92ꢀ to 102ꢀ [95.5(2)ꢀ] such that the I
atom lies slightly out of the plane toward the oxide ligand.
Both the EDG and molecular geometry is unambiguously
pentagonal-bipyramidal. Christe, Schrobilgen, and co-
workers26 present a detailed treatment of the geometry.
p-(Dichloroiodo)nitrobenzene (19; Figure 6)270uses two
HMIBA
HTIBA
8.12
8.09
7.58
7.51
7.48
7.41
2.72
2.33
a For CD3OD, δ are referenced to CHD2OD at 3.31 ppm; in CDCl3,
δ are referenced to CHCl3 at 7.240 ppm. The tabulated δ are multiplet
centers. All samples are prepared with 10 mg of solid per 1 mL of solvent.
Spectra were taken at room temperature.
protons from the MsO- ligands appeared as a sharp
singlet at 2.71 ppm, far from that of free CH3SO3H
at 3.14 ppm, suggesting that the CH3SO2O-I bonds
remain intact in a chloroform solution. The aromatic
1H shifts for HTIBA were slightly removed from those of
HMIBA, again consistent with retention of the ligands by
the I atoms.
0
˚
˚
intermolecular bonds (I1 O1 ,3.286A;I1 O2 , 3.164 A)
3 3 3
3 3 3
to achieve pentagonal-bipyramidal EDG. The Cl-I-Cl
axis is linear (—Cl1-I1-Cl2, 176.17ꢀ), and the two lone
pairs lie in the equatorial plane. The axis is tilted with
respect to the plane as the angle of segment Cl2-I1 to plane
C1-O10-O20 =74.3ꢀ. Other CN 7 species with pentagonal-
bipyramidal EDG17 include the λ3-iodanes [bis(acetato-
O)iodo]benzene (20),28 [bis(dichloroacetato-O)iodo]benzene
(21),28 [[(p-toluenesulfonyl)imino)iodo)-p-toluene (22),29
I2 in μ-oxobis[acetato-O(phenyl)iodine(III)] (23),13 and
I1 in μ-oxobis[nitrato-O(phenyl)iodine(III)] (24);8 the
λ5-iodane 1-(tert-butylsulfonyl)-2-(dioxoiodo)benzene
(25);22 and the λ7-iodane anion trans-IO2F52- (26).
Three of the I atoms in this study displayed CN 7 with
capped octahedral EDG. Literature examples of this geo-
metry17 are provided by I1 in μ-oxobis[acetato-O(phenyl)-
iodine(III)] (23),13 I2 in μ-oxobis[trifluoroacetato-O(phenyl)-
iodine(III)] (27),9 and the (arylsulfonylimino)iodoarene
m-tolylINTs (28).30 The capped octahedron evolves to a
capped triangular prism if the capping atom and one of
the axial occupants migrate somewhat, and the assignment
Discussion
EDG of the I Atoms. Of the five compounds reported
here, one has CN 5 with trigonal-bipyramidal EDG (HIIBA,
I22), six have CN 7 with pentagonal-bipyramidal (HMIBA,
I1; HCIBA, I1; HIIBA, I2) or capped octahedral (HMIB;
HCIBA, I2; HIIBA, I1) EDG, and two have CN 8 with
triangular dodecahedral EDG (HTIB; HMIBA, I2). These
geometries and others can be found in literature com-
pounds (Figure 6).17
There are examples in the literature of organoiodine
species with CN 5 and trigonal-bipyramidal EDG; the
I atom in [[(p-toluenesulfonyl)imino]iodo]-o-toluene (10;
Figure 6)18 is CN 5, with two unshared electron pairs and
0
˚
one strong I O bond (I1 O2 , 2.826 A). The axial
segment is bent (—N1-I1 O2 , 168.8ꢀ), virtually match-
3 3 3
3 3 3 0
ing the axial segment containing I22 in HIIBA.
3 3 3
(20) Minkwitz, R.; Berkei, M. Inorg. Chem. 1999, 38, 5041–5044.
(21) Archer, E. M.; van Schalkwyk, T. G. D. Acta Crystallogr. 1953, 6,
88–92. Carey, J. V.; Chaloner, P. A.; Hitchcock, P. B.; Neugebauer, T.; Seddon,
K. R. J. Chem. Res., Miniprint 1996, 2031–2054. J. Chem. Res., Synop. 1996,
358-359. Montanari, V.; Des Marteau, D. D.; Pennington, W. T. J. Mol. Struct.
2000, 550, 337–348.
(22) Macikenas, D.; Skrzypczak-Jankun, E.; Protasiewicz, J. D. Angew.
Chem., Int. Ed. 2000, 39, 2007–2010.
(23) Mishra, A. K.; Olmstead, M. M.; Ellison, J. J.; Power, P. P. Inorg.
Chem. 1995, 34, 3210–3214.
(24) Protasiewicz, J. D. Chem. Commun. 1995, 1115–1116.
(25) Christe, K. O.; Dixon, D. A.; Mahjoub, A. R.; Mercier, H. P. A.;
Sanders, J. C. P.; Seppelt, K.; Schrobilgen, G. J.; Wilson, W. W. J. Am.
Chem. Soc. 1993, 115, 2696–2706.
(26) Boatz, J. A.; Christe, K. O.; Dixon, D. A.; Fir, B. A.; Gerken, M.;
Gnann, R. Z.; Mercier, H. P. A.; Schrobilgen, G. J. Inorg. Chem. 2003, 42,
5282–5292.
(27) Nikiforov, V. A.; Karavan, V. S.; Miltsov, S. A.; Selivanov, S. I.;
Kolehmainen, E.; Wegelius, E.; Nissinen, M. ARKIVOC 2003, 4, 191–196.
(28) Alcock, N. W.; Countryman, R. M.; Esperas, S.; Sawyer, J. F.
J. Chem. Soc., Dalton Trans. 1979, 854–860.
(29) Boucher, M.; Macikenas, D.; Ren, T.; Protasiewicz, J. D. J. Am.
Chem. Soc. 1997, 119, 9366–9376.
None of the I atoms here has CN 6, but iodine fre-
quently achieves CN6 and octahedral EDG. The tetra-
μ-oxopentaiodanyl dication repeat units in the phenyl-
iodine(III) perchlorate polymer prepared earlier3 has five
distinct I atoms: of these, I1 and I5 have octahedral EDG
(11; Figure 6). I1 has a secondary bond to a perchlorate
counterion (I1 O10 , 3.140 A) and two unshared pairs.
The four-atom equatorial plane is puckered [average
˚
atomic displacements of 0.215(40) A], with the I atom
0
˚
3 3 3
5
˚
0.197 A from the plane. The λ -iodane (2-iodylphenyl)-
diphenylphosphine oxide (12; Figure 6)19 uses a strong
0
˚
intermolecular bond (I1 O2 , 2.571 A) and a strong intra-
3 3 3
˚
molecular bond (I1 O3, 2.612 A) to yield an octahedral
3 3 3
(17) Coordinates from the CCDC files are used to construct these figures
and additional figures in the Supporting Information.
(18) Cicero, R. L.; Zhao, D.; Protasiewicz, J. D. Inorg. Chem. 1996, 35,
275–276.
(19) Meprathu, B. V.; Justik, M. W.; Protasiewicz, J. D. Tetrahedron Lett.
2005, 46, 5187–5190.
(30) Boucher, M.; Macikenas, D.; Ren, T.; Protasiewicz, J. D. J. Am.
Chem. Soc. 1997, 119, 9366–9376.

5420 Inorganic Chemistry, Vol. 49, No. 12, 2010
Richter et al.
Figure 6. EDGsofthe I atoms in literature sources. Primary bonds aregiven inblack;secondary bonds aregiven ingreen;unsharedelectronpairsare given
as blue wedges. Fine black lines are used to clarify geometric features. The figures were prepared using MDL ISIS/Draw 2.5 from structures generated by
Mercury 2.2, using CCDC data, except for 18, which was produced from drawings in the original publication.
0
˚
3.191 A; I2 O5 , 2.560 A) and one intramolecular bond
˚
of a capped octahedral or capped triangular prism to an
EDG sometimes may be ambiguous. The (arylsulfonyl-
imino)iodoarene PhINTs (29; Figure 6)230has three sec-
3 3 3
˚
(I2 O7, 2.698 A) that likewise produce triangular
3 3 3
dodecahedral EDG. Numerous examples of CN 8 with
capped pentagonal-bipyramidal EDG appear,17 includ-
ing I atoms in tris(acetato-O)iodine(III) (33; Figure 6),33
[bis(trifluoroacetato-O)iodo]benzene (34),34 I1 in μ-oxo-
[nitrato-O(phenyl)iodine(III)][phenyl(trifluoroacetato-
O)iodine(III)] (35),11 the (arylsulfonylimino)iodoarenes
m-tolylINSO2Ph (36)30 and m-tolylINSO2-p-NO2C6H4
(37),30 I1 in μ-oxobis[trifluoroacetato-O(phenyl)iodine-
(III)] (27),9 and o-[dichloro(iodo)]nitrobenzene (38;
Figure 6).27 A third CN 8 geometry is exhibited by the
˚
˚
ondary bonds (I1 O2, 3.144 A; I1 O1 , 3.271 A; I1-
3 3 3
3 3 3
0
˚
N1 , 2.482 A) that combine with two primary bonds to
produce a planar bow-tie-shaped base to give a “square”-
˚
pyramidal molecular shape; the I atom is only 0.004 A
from the O2-N1-O10-N10 plane (maximum atomic dis-
placement of 0.03 A in the plane). The most likely location
˚
of the two equivalent unshared pairs is below the bow-tie
plane, opposite to the C atom, providing the cross-bar for
a capped triangular prismatic EDG. Similar examples17
are provided by the (arylsulfonylimino)iodoarene Me-
sINTs (30)23 and [difluoro(iodo)]trifluoromethane (31).31
The two instances of CN 8 in this study display tri-
angular dodecahedral EDG. I2 in the λ5-iodane 2-iodoxy-
benzoic acid isopropyl ester (32; Figure 6)32 has three
-
λ5-iodane IF6 (39; Figure 6):35 Six primary bonds with
F atoms, one intermolecular secondary bond (I F60,
3 3 3
˚
2.817 A), and one unshared pair of electrons are arrayed
in a cubic antiprismatic EDG.
00
˚
intermolecular I O bonds (I2 O2 , 3.051 A; I2 O1,
3 3 3 3 3 3 3 3 3
(33) Birchall, T.; Frampton, C. S.; Kapoor, P. Inorg. Chem. 1989, 28, 636–
639.
(31) Minkwitz, R.; Berkei, M. Inorg. Chem. 1998, 37, 5247–5250.
(32) Zhdankin, V. V.; Litvinov, D. N.; Koposov, A. Y.; Luu, T.;
Ferguson, M. J.; McDonald, R.; Tykwinski, R. R. Chem. Commun. 2004,
106–107.
(34) Alcock, N.; Harrison, W. D.; Howes, C. J. Chem. Soc., Dalton Trans.
1984, 1709–1716.
(35) Mahjoub, A. R.; Seppelt, K. Angew. Chem., Int. Ed. Engl. 1991, 30,
323–324.

Article
Inorganic Chemistry, Vol. 49, No. 12, 2010 5421
Though not seen in the presented compounds, I atoms
with CN 9 are to be found in the literature.17 I2 in 35
(Figure 6)11 achieves CN 90using four secondary bonds
0
˚
(I2 O3, 3.124 A; I2 O5 , 3.191 A; I2 O4 , 3.379 A;
˚
˚
3 3 3
3 3 3
3 3 3
00
˚
I2 O5 , 3.381 A) and produces a bicapped pentagonal-
3 3 3
bipyramidal EDG. The pentagonal plane O1-C9-
O2-O3-O50 is well formed and only lightly puckered
with an average atomic displacement of 0.118(64) A, and
˚
˚
I2 is only 0.020 A out of the plane. The I-centered angles
approach the ideal 72ꢀ, where O3 I2-O2 is con-
3 3 3
strained to be small (45.36ꢀ) owing to tethering. A second
example of an I atom with CN 9 and bicapped pentagonal-
bipyramidal EDG is provided by the λ5-iodane IF2-
(O)OCH3 (40; Figure 6).36 With one unshared pair of
Figure 7. Dependence of the C-I-O angles on the I-O bond order (n);
(9, filled in red) data from the reported compounds; (Δ, filled in yellow)
data from polymer 11; (b, filled in green) data from literature λ3-iodanes;
(ꢀ) data from literature cyclic λ3-iodanes; (*) data from literature iodoxy-
benzene analogues; (O) literature benziodoxazoles, etc. Data for the plot
are given in the Supporting Information.17 Bond orders are calculated
0
˚
electrons and four secondary bonds (I1 O1 , 3.413 A;
0
3 3 3
00
000
˚
˚
˚
I1 F2 , 2.876 A; I1 F1 , 3.278 A; I1 O1 , 2.645 A),
3 3 3
3 3 3
3 3 3
a lightly puckered pentagonal plane is produced with an
˚
average atomic displacement of 0.102(49) A, where I1 is
˚
displaced by 0.129 A.
˚
using D(l) = 1.99 A. The line in the linear regression fit to data for repor-
ted compounds, polymer 11, and literature λ3-iodanes.
T-Shaped Bond. An enduring point of interest in aryl
λ3-iodanes and μ-oxodiiodanes is the predicted T-shaped
bond formed by the I atoms with three ligands, where one
ligand is an aryl group. When the possible influence of
secondary bonds is excluded, the EDG about the iodine is
trigonal-bipyramidal, where the equatorial aryl ligand
bonds to iodine by ordinary covalent overlap, while the
two axial ligands join in a 3c-4e bond with the central
I atom.6 The delocalized apical unit (L1-I-L2) can be
symmetrically or unsymmetrically polarized, depending
on the relative electronegativities of the ligands. Symme-
trical polarization gives fractional and equivalent I-L
bond orders; unsymmetrical polarization produces none-
quivalent bond orders. The I-O bond distances of aryl
λ3-iodanes with two oxyanion ligands can be grouped into
three categories. If the ligands are identical, the I-O
bonds are about the same length and longer than the
Figure 8. Diagram of hexagons formed in [dichloro(iodo)]benzene ana-
logues.
Table 5. Hexagons in [Dichloro(iodo)]benzene Analoguesa
b
˚
distance (A)
angle (deg)
˚
sum of the covalent radii (2.06 A); when the ligands are
not identical and differ substantially in electronegativity,
I-0 I1 Cl20 Δ-0 )-0 I1-Cl2 I10 Cl1-Cl2-Cl10
3 3 3
3 3 3
94.75
95.20
92.69
˚
the more basic ligand gives a short I-O bond (<2.06 A),
38 0.019
16 0.058
17 0.033
3.383
3.490
3.816
20.84 0.51
0.60 1.56
54.14 0.90
131.23
128.82
124.89
while the other is “extra” long. This pattern is seen in the
present compounds where the bond orders (n) can be
calculated from the Pauling equation, D(n) = D(l) - 0.6
log n, where D(n)=observed I-O bond distance and D(l)=
I-O distance computed from I and O covalent radii.6 For
both symmetrical and unsymmetrical polarization, C-I-O
angles of 90ꢀ are expected; however, a droop-and-shrug
motif is generally seen, where one angle is larger and the
other smaller than 90ꢀ. When the C-I-O angles are plot-
ted against the bond order for the reported compounds,
a Refer to Figure 8 for atom labels: (0) plane Cl1-Cl2-Cl10-Cl20;
P
(Δ) plane Cl1-C-Cl2; ()) plane I1-Cl2-I10-Cl20. b The vdw limit
˚
for I-Cl is 3.95 A.
O-O-C-O hexagons seen in the reported compounds.
However, there are numerous examples of compounds
that do give this structure: [bis(trifluoracetato-O)iodo]-
benzene (34),34 [bis(dichloroacetato-O)iodo]benzene (21),28
μ-oxo-bis[acetato-O(phenyl)iodine] (23),13 and the mixed
μ-oxodiiodane 3511 all produce similar hexagons (Figure 4
and Table 3).
Analogues of dichloro(iodo)benzene also produce chair-
conformation hexagons, where the structure arises from
alignment of the Cl-I-Cl segments from neighboring
molecules; the bonds supporting the structure are intra-
polymer 11, and a group of literature λ3-iodanes,17
linear relationship appears (Figure 7). The I-sulfonate
bonds in HMIB and HTIB, as well as the terminal I
a
O
3 3 3
bonds in polymer 11 (all with very small bond orders),
seem to be outliers; with these four I-O bonds excluded, a
regression fit of 44 I-O bonds gives —C-I-O(deg) =
74.6(20) þ 17.7(11)n. Figure 7 also shows data for cyclic
λ3-iodanes (ꢀ), iodoxybenzene analogues (*), and additional
λ5-iodanes (O). The linear correlation fails for n > 1.5.0
O-C-O-O-C-O Hexagons. Not all aryl λ3-iodanes
and μ-oxodiiodanes form the chair-conformation O-C-
molecular I Cl secondary bonds (Figure 8 and Table 5).
Examples are provided by o-[dichloro(iodo)]nitrobenzene
3 3 3
(38),27 [dichloro(iodo)]-2,4,6-triisopropylbenzene (16),23
and 1-17.24 The Cl1-Cl2-Cl1 -Cl2 seats are flat (0.000 A
atomic displacement), and the I atoms are nearly in the
plane in each case. In all three compounds, the seat
0
0
˚
(36) Minkwitz, R.; Berkei, M.; Studentkowski, M.; Ludwig, R. Inorg.
Chem. 2000, 39, 4766–4768.
˚
contains a flat (0.000 A atomic displacement), nearly

5422 Inorganic Chemistry, Vol. 49, No. 12, 2010
Table 6. Crystallographic Data for HMIB, HMIBA, HCIBA, and HIIBAa
HMIB
Richter et al.
HMIBA
HCIBA
HIIBA
empirical formula
fw (g/mol)
cryst syst
space group
cryst color, habit
˚
cell lengths (A)
C7 H9 IO4S
316.11
monoclinic
P21/c
colorless block
a=6.1902(2)
b=7.4487(2)
c=21.8864(4)
R=90.00
β=94.8237(4)
γ=90.00
1005.70(3), 4
2.088
C14 H16 I2 O7 S2
614.20
triclinic
C16 H14Cl2I2 O5
610.99
monoclinic
P21/c
faint yellow, needles
a=9.7488(2)
b=22.0264(3)
c=18.2010(2)
R=90.00
β=90.5158(6)
γ=90.00
3908.16, 8
2.077
C16 H14I4 O5
793.89
triclinic
P1
P1
bright yellow, thin blade
a=5.8908(2)
b=11.5575(5)
c=14.5665(6)
R=102.5504(10)
β=98.2055(10)
γ=101.3640(12)
931.05(6), 2
2.191
colorless needles
a=9.7924(2)
b=13.6145(2)
c=16.6725(2)
R=75.2793(2)
β=82.2582(9)
γ=80.5734(3)
2110.65,4
2.498
cell angles (deg)
3
volume (A ), Z
˚
density(calcd) (g/cm3)
μ(Mo KR) (cm-1
R(F) (%)b
)
33.72
2.91
8.25
36.35
4.96
13.52
35.15
4.27
14.51
59.27
4.95
16.65
R(wF2) (%)b
P
P
P
P
a
In all cases, temperature = 173(2) K and wavelength = 0.7103 A. b Quantity minimized = R(wF2) = [w(Fo2 - Fc2)2]/ [w(Fo2)2]1/2; R= Δ/ (Fo),
˚
Δ=|(Fo - Fc)|I.
rectangular I1-Cl2 I10-Cl20 “diamond”; the covalent
These geometries are achieved using primary bonds, un-
shared pairs of electrons, and secondary bonds between I
and O, N, Cl, and Fl atoms. There is no correlation between
the oxidation state of iodine and the coordination number or
EDG. For both aryl λ3- and λ5-iodanes with two or more
O-centered ligands, the C-I-O angle increased correspond-
ingly with the I-O bond order; this relationship and the
EDG geometries seen bear on the 3c-4e view of the predicted
T-shaped bond in these compounds. The possible presence of
delocalized bonding in the hexagonal/diamond groupings
arising from the antiparallel alignment of O-I-O segments
from two molecules is supported by elevation of the melting
point in HCIBA that can be attributed to hydrogen bonding
to the ring.
3 3 3
˚
I-Cl sides are between 2.45 and 2.53 A, while the inter-
molecular I Cl sides are in each case less than the
˚
3 3 3
P
vdw limit (3.95 A). In all of these examples, the dia-
mond (I-D-I0-D0) structure appears, and this may exhi-
bit delocalized bonding that stabilizes the hexagon.
Physical Properties and Hydrogen Bonding. The solu-
bility of HMIBA and HTIBA in chloroform is remark-
able given the complete insolubility of HMIB and HTIB
in this solvent. This difference likely arises from the strong
˚
hydrogen bonds (O H, 1.860 and 2.004 A) that bind the
3 3 3
dimers in HMIB and HTIB that are absent in the anhy-
drides. This hydrogen bonding may likewise be the source
of the higher melting point of HTIB relative to that of
HTIBA. Also noteworthy is that the melting point of
HCIBA is much higher than that of HIIBA, which has the
higher molar mass. In both HCIBA and HIIBA, dimers
Experimental Section
Analytical Methods. All NMR spectra were obtained on a
Varian VXR 300 MHz spectrometer equipped with a broad-
band probe. Elemental analyses were performed either at Micro-
Tech Laboratories, Skokie, IL, or Galbraith Laboratories,
Knoxville, TN.
are joined into stair structures by similar strong I
O
3 3 3
bonds. The HCIBA stairs are stabilized by the “tail”
containing I2 that dangles from the vertex of the O-C-
O-O-C-O hexagon and places the chloromethyl group
directly above the hexagon/diamond groupings in the
neighboring dimer; the chloromethyl group rotates so
that H27 points to the center of that hexagon, forming a
Crystal, data collection, and refinement parameters are given
in Table 6. A suitable crystal was selected, mounted in a N2-
flushed, thin-walled capillary, and flame-sealed. All data were
collected on a Siemens P4 diffractometer equipped with a
SMART/CCD detector. The structure was solved using direct
methods completed by subsequent difference Fourier syntheses
and refined by full-matrix least-squares procedures. An empiri-
cal absorption correction was applied, based on a Fourier series
in the polar angles of the incident and diffracted beam paths,
and was used to model an absorption surface for the difference
between the observed and calculated structure factors.38 All
software and sources of the scattering factors are contained in
the SHELXTL (5.10) program library (Sheldrick, G. SHELXTL;
Bruker AXS: Madison, WI).
˚
rectangular pyramid with H27 at the apex, 2.183 A above
the seat of the hexagon (Figures 3 and 4). Possibly,
delocalized bonding in the hexagon/diamond grouping
provides the electron density that is shared with H27,
which is electron-deficient because of the Cl atom on
the chloromethyl group; this explanation of the elevated
melting point of HCIBA presents an example where
hydrogen-bonding forces outweigh those in the I
O
3 3 3
secondary bonding.37
Preparation of HMIBA and HTIBA. (Diacetoxyiodo)benzene
and toluenesulfonic acid monohydrate were purchased from Aldrich
Chemical Co. and used directly. HTIB and HMIB were prepared as
described previously.2 HMIBA was prepared from acetonitrile solu-
tions of HMIB by stripping away water with a continuous CH3CN
distillation; HTIBA was similarly prepared from HTIB. HMIBA
was stable for long periods when stored under N2 at -70 ꢀC.
HMIBA mp 149-150 ꢀC (dec); HTIBA mp 123-125 ꢀC (dec).
HMIBA and HTIBA are soluble in CHCl3, 33 and 16 mg/mL.
Conclusions
In a survey of the reported compounds and literature
compounds, coordination numbers used by iodine include
5-9. The I-centered EDGs found include the trigonal bipyr-
amid, octahedron, pentagonal bipyramid, capped octa-
hedron, capped triangular prism, capped pentagonal bipyr-
amid, dodecahedron, and bicapped pentagonal bipyramid.
(37) Batchelor, R. J.; Birchall, T.; Sawyer, J. F. Inorg. Chem. 1986, 25,
1415–1420.
(38) Walker, N.; Stuart, D. Acta Crystallogr. 1983, A39, 158–166.

Article
Preparation of HCIBA and HIIBA. HMIB (1.00 g, 3.16 mmol)
Inorganic Chemistry, Vol. 49, No. 12, 2010 5423
followed by vacuum filtration and washing with ether (yield =
0.38 g).
dissolved in 10 mL of water was placed in a 25-mL graduated
cylinder. Aqueous chloroacetic acid (0.32 g, 3.16 mmol) neutralized
with 1 M NaOH for a total volume of 7.0 mL was layered on top of
the HMIB solution, yielding a clear solution on top of the lemon-
yellow HMIB solution. After 24 h, two types of solid were observed:
(a) well-formed very-pale-yellow, long and flat or needle-shaped
crystals and (b) yellowish “mold” mounds. The very-pale-yellow
crystals (yield=0.71 g) were subjected to X-ray structure analysis.
Anal. Obsd (calcd for C16H14Cl2I2O5): C, 31.26 (31.45); H, 2.45
(2.31); I, 43.05 (41.54).
Acknowledgment. Our thanks go to Prof. Ann D. Bolek of
Science and Technology Library of The University of Akron
for her support of this research. Financial support was given by
The University of Akron, the University of Delaware, and
Remington Products (Wadsworth, OH). Figures and structures
were prepared using MDL ISIS/Draw 2.5, Mercury 2.2 from the
Cambridge Crystallographic Data Centre, and ArcSoft Photo-
Studio 5.5.0.72.
Similarly for HIIBA, HMIB (1.00 g, 3.16 mmol) in 10 mL of
water was placed in a 25-mL graduated cylinder. Iodoacetic acid
(0.59 g, 3.16 mmol) was neutralized with 3.1 mL of 1 M NaOH
(3.1 mmol) and diluted with water to 10 mL; this solution was
layered on top of the lemon-yellow HMIB solution for a total
volume ≈ 20 mL. After 1 day, long white needles grew from
the interface into the HMIB solution phase. The very white
needles were collected by gentle swirling of the cylinder contents
Supporting Information Available: Crystal data and structure
refinement, atomic coordinates, bond lengths and angles, and
anisotropic displacement coefficients for HMIB, HMIBA, HCIBA,
and HIIBA in CIF files, table of values of the bond orders for the
reportedcompoundsandforliteraturecompoundsusedforFigure7,
structures of literature I atoms referenced in the article. This material
is available free of charge via the Internet at http://pubs.acs.org.