Crystal and molecular structure of diphenyliodonium triiodide

Article abstract of DOI:10.1134/S0036023612020064

A new salt diphenyliodonium triiodide (C₁₂H₁₀I ₄) was obtained. The [C₁₂H₁₀I ⁺][I₃^-] compound was isolated as red brown crystals and studied by single-crystal X-ray diffraction. The structure of diphenyliodonium triiodide consists of separate, virtually linear I ₃^- anions and C₁₂H₁₀I⁺ cations. Strong intermolecular anion-anion (I₃ ^-?I₃^-) and anion-cation (I ₃^- ?I⁺) interactions in the crystal structure leads to a change in the symmetry of triiodide ions. The complex formation in the system organic cation iodide-elementary iodine was studied by spectrophotometry. The complex composition was found (1:1), and the stability constant of the complex in chloroform was determined (logβ = 3.91). Pleiades Publishing, Ltd., 2012.

Full text of DOI:10.1134/S0036023612020064

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2012, Vol. 57, No. 2, pp. 193–196. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © M.S. Chernov’yants, I.V. Burykin, Z.A. Starikova, A.A. Rostovskaya, 2012, published in Zhurnal Neorganicheskoi Khimii, 2012, Vol. 57, No. 2, pp. 235–239.
COORDINATION COMPOUNDS
Crystal and Molecular Structure of Diphenyliodonium Triiodide
M. S. Chernov’yantsa, I. V. Burykina, Z. A. Starikovab, and A. A. Rostovskayaa
a Southern Federal University, ul. Bolshaya Sadovaya 105/42, RostovꢀonꢀDon, 344006 Russia
b Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
ul. Vavilova 28, Moscow, 119991 Russia
Received October 28, 2010
Abstract—A new salt diphenyliodonium triiodide (C12H10I4) was obtained. The [C H I+][ −] compound
I3
12 10
was isolated as red brown crystals and studied by singleꢀcrystal Xꢀray diffraction. The structure of diphenyliꢀ
odonium triiodide consists of separate, virtually linear − anions and C12H10I+ cations. Strong intermolecular
I3
−
anion–anion ( −··· −) and anion–cation ( ···I+) interactions in the crystal structure leads to a change in the
I3 I3
I3
symmetry of triiodide ions. The complex formation in the system organic cation iodide–elementary iodine
was studied by spectrophotometry. The complex composition was found (1 : 1), and the stability constant of
the complex in chloroform was determined ( log
β
= 3.91).
DOI: 10.1134/S0036023612020064
Among large amount of iodineꢀcontaining organic
compounds, iodonium salts receive attention in the
literature. In these salts, I+ ions are bound to carbon
atoms of aryl (hetaryl) groups (R) or coordinated to
heteroaromatic thioamides. Compounds of the first
type exhibit antibacterial activity against anaerobic
microorganisms [1]. Last 20 years, new reagents based
on polyvalent iodine compounds play an increasing
role in preparative organic chemistry; they are used in
organic synthesis as oxidants and electrophilic agents
[2, 3]. A limited number of iodonium salts of the secꢀ
ond type are known. These compounds are produced
by reactions of heteroaromatic thioamides with
molecular iodine following by formation of cationic
dimers of thioamide with bridging iodine atom and triꢀ
iodide counterion [4–6].
EXPERIMENTAL
Synthesis
.
Diphenyliodonium triiodide was
obtained by iodination of diphenyliodonium iodide
with molecular iodine. A weighed portion (0.0350 g,
8.58
Alfa Aesar) was dissolved in a methanol–chloroform
mixture (1 : 2), and iodine (0.0218 g, 8.58
10–5 mol)
×
10–5 mol) of diphenyliodonium iodide (98%,
×
was dissolved in chloroform. After mixing the soluꢀ
tions, the solvent was removed by slow evaporation at
room temperature. The C12H10I4 compound syntheꢀ
sized is a crystalline substance of red brown color;
T
m = 125–128 С.
°
1H NMR spectra were recorded in CDCl3 on a
Bruker DPX 600 diffractometer.
1H NMR of diphenyliodonium iodide (CDCl3),
δ
,
ppm: 7.40 (t, 4H,
4H, ꢀСН, JН, Н = 7.56).
1H NMR of diphenyliodonium triiodide (
(CDCl3), , ppm: 7.11 (m, 2H,
ꢀCH2; 2H,
1H, ꢀCH,
1 = 8.22,
Electronic absorption spectra of chloroform soluꢀ
mꢀCH), 7.55 (t, 2H, pꢀCH), 7.96 (d,
Iodonium salts of the first type have closely associꢀ
ated anionic parts of the molecules and form pseudoꢀ
о
1)
trigonal bipyramids with the RIR angles close to 90 .
°
δ
m
ꢀCH), 7.39 (m, 2H,
ꢀCH), 7.58 (m, 1H, ꢀCH), 7.71 (dd,
2 = 1.11), 7.96 (dd, 2H, ꢀCH,
Search of unique properties opening new applicaꢀ
tion fields of iodine complexes of different nature
stimulates target synthesis of iodonium salts containꢀ
ing additional iodine molecule in complex triiodide
p
m
o
o
J
1 = 8.19,
J
o
J
J2 = 1.00).
ion of the composition {R2I+ − } and their experimenꢀ
I3
tions with various ratios between concentrations of
organic cation iodide and elementary iodine were
recorded in a range of 250–800 nm in quartz cuvettes
of path length l = 1 cm on a Varian Cary 50 spectroꢀ
photometer. A solution of diphenyliodonium iodide
tal and theoretical studies including Xꢀray crystallogꢀ
raphy. Evaluation of bioactivity and other properties
directly dependent on the iodine form is impossible
without studying structural features and stabilities of
iodineꢀcontaining compounds.
with the constant concentration of 2.0
×
10–5 mol/L
was used as an initial solution. The ratio between
diphenyliodonium iodide and elementary iodine in
the reaction mixture was varied from 1 : 1 to 1 : 15.
The new salt diphenyliodonium triiodide
(
C12H10I4,
1) was synthesized by mixing chloroform
solutions of diphenyliodonium iodide and molecular
Xꢀray crystallography. Crystals of
1
(C12H10I4,
21/
iodine; compound
brown crystals.
1 was isolated in the form of red
FW = 661.80) are monoclinic, space group
P
c,
193

194
CHERNOV’YANTS et al.
I(1)
C(12)
I(4)
C(11)
C(7)
C(1)
C(10)
C(8)
C(6)
C(5)
C(2)
C(9)
I(3)
C(3)
C(4)
I(2)
Fig. 1. Linear I3− anions and
C H I diphenyliodonium cations in crystal structure of C H I .
12 10 12 10 4
+
residual electron density were 0.912 and –1.282 e Å–3,
respectively. All calculations were performed with the
SHELXTL PLUS 5 program package [8].
unit cell parameters at 100(2) K are
17.6277(10) = 14.7481(8) Å,
90.048(1)
= 1549.92(14) Å3
a
= 5.9618(3)
= 90
= 4, ρcalc
Å
,
b
=
=
=
Å
= 90
,
c
α
°
,
β
°,
γ
°;
V
;
Z
2.836 g/cm3. The experimental array of 16427 reflecꢀ
tions was obtained on a Bruker SMART APEX2 CCD
RESULTS AND DISCUSSION
diffractometer at 100(2) K (
ite monochromator, θmax = 58°) from a single crystal
with dimensions of 0.45 0.25 0.20 mm. Correction
for absorption (
= 8.017 mm–1) was applied with the
λ
МоК radiation, graphꢀ
α
The equilibrium in the system organic halide–
molecular iodine in chloroform was studied by specꢀ
trophotometry. The amount of iodine molecules coorꢀ
dinated to diphenyliodonium iodide and stability conꢀ
stants were determined with the use of the average
2
×
×
μ
use of the SADABS program [7] (transmission coeffiꢀ
cients Tmax and Tmin are, respectively, 0.297 and 0.123).
After averaging equivalent reflections, 3695 indepenꢀ
dent reflections (R(int) = 0.0393) were used to solve
and refine the structure. The structure was solved by
the direct method; all nonꢀhydrogen atoms were
iodine number
described elsewhere [9].
nI ,
2
The equilibrium iodine concentration ([I2]) was
calculated from the absorbance at the maximum waveꢀ
length of the absorption band of elementary iodine
(
Amax) by equation [I2] =
A
max/(
l
εI2
).
Fh2kl
final discrepancy factors were
refined on
in anisotropic approximation. The
The stability constant
β
at 0 < < 1 was calculated
nI
2
R1
= 0.0236 (calculated
> 2 )), wR2 =
by the least squares method by equation
/(1 – ) = [I2], log = 3.91 0.02.
on Fhkl for 3568 reflections with
I
σ(I
2
β
β
n
I2
n
I2
0.0547 (calculated on
for all independent reflecꢀ
Fhkl
tions), GOOF = 1.021, the number of the reflections
refined was 145, the maximum and minimum values of the
The formation of diphenyliodonium triiodide in a
chloroform solution can be represented by equilibꢀ
−
rium R2I+I– + I2
R2I+ Red brown crystals were
I3 .
isolated on slow evaporation of the solvent.
The molecular and crystal structures of salt
studied by Xꢀray crystallography. The structure of
Bond lengths (
d
) and bond angles (
ω
) for compound
1
1
were
Bond
d
, Å
Angle
ω
, deg
diphenyliodonium triiodide consists of separate,
I(2)–I(3)
I(3)–I(4)
3.072
2.814
2.140
2.103
1.393
1.389
1.388
1.387
1.405
1.381
I(2)I(3)I(4)
174.20
92.54
−
nearly linear
anions and C12H10I+ cations (Fig. 1).
I 3
C(1)I(2)C(7)
I(1)C(1)C(6)
I(1)C(1)C(2)
C(1)C(2)C(3)
C(2)C(3)C(4)
C(3)C(4)C(5)
C(4)C(5)C(6)
C(5)C(6)C(7)
C(6)C(1)C(2)
The angle III is 174.20 , and the I(2)–I(3) and
°
I(1)–C(1)
I(1)–C(7)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
C(6)–C(1)
118.02
118.97
118.04
120.55
120.55
120.47
117.66
123.01
I(3)–I(4) distances are equal to 3.072 Å and 2.814 Å,
respectively.
Figure 2 shows the crystal packing of the layers parꢀ
allel the x0z plane. Unusual VanꢀderꢀWaals interacꢀ
tions I···H exist between the layers; the shortest interꢀ
atomic contacts between the layers are I(3)···H(5А)
and I(4)···H(3A) (3.17 Å and 3.26 Å, respectively).
The structure consists of the layers formed due to
dipole–dipole interactions of iodine atoms of iodonium
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 2 2012

CRYSTAL AND MOLECULAR STRUCTURE
195
a
c
0
b
Fig. 2. Fragment of crystal structure of [
C
H
12 10
I ][I3−].
+
I(1')
I(2')
a
I(2)
I(1)
I(3)
I(4)
I(4')
c
0
b
Fig. 3. Structure of a layer formed by dipole–dipole interactions I···I (I(1)···I(2) 3.4686(3)
Å
(–
x
Å
+ 1,
(–
y
+ 1/2, –
z
+ 3/2),
+ 2))
3.6212(4) , – + 3/2, + 1/2), 4.0328(3) (– + 2, + 1/2, – + 3/2), I(4)···I(4 ) 3.7787(5)
Å
(
x
y
z
Å
x
y
z
'
x
, – + 1,
y
⎯
z
.
cations with those of triiodide anions (Fig. 3); only weak
contacts I···H occur between the layers (Fig. 2).
Therefore, the molecular and crystal structure of
diphenyliodonium triiodide was studied for the first
time by Xꢀray crystallography. The C–I bond length in
iodonium cation virtually coincides with the bond of
the analogous bond in alkyl iodides. Triiodide ions are
asymmetric due to different character of intermolecuꢀ
The C–I bond lengths in the cationic moiety are
somewhat different; the C(1)–I(1) distance (2.140 Å)
nearly coincides with C–I that in alkyl iodides (Table).
The torsion angles I(1)C(1)C(2)C(3) and lar interactions of their terminal atoms. The correꢀ
C(2)I(1)C(8)C(7) in the diphenyliodonium triiodide
molecule are 178.3(3)° and 85.5(3)°, respectively.
sponding bond lengths with the central atoms of two
iodonium cations are 3.469 Å and 3.621 Å, and those
with the terminal iodine atom of the triiodide ion of an
adjacent molecule are equal to 3.779 Å) (I–I chains of
The average C–C bond length in the phenyl rings is
close to the standard value [10], and the carbon atoms
do not deviate from the ring plane (the deviation is less
than 1.14°).
−
−
the (I+) ··· ··· ···(I+) type are formed). The evaluaꢀ
I3 I3
2
2
tion of the capability of diphenyliodonium triiodide to
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 2 2012

196
CHERNOV’YANTS et al.
5. M. S. Chernov’yants, N. V. Aleshina, Z. A. Starikova,
and E. N. Sul’zhenko, Izv. Akad. Nauk, Ser. Khim.,
No. 9, 1750 (2010).
keep molecular iodine in a chloroform solution was
made.
6. V. Daga, S. K. Hadjikakou, N. Hadjiliadis, et al., Eur. J.
Inorg. Chem., 1718 (2002).
7. APEX2 Software Package, Bruker, Inc., 5465, East
Cheryl Parkway, Madison, WI 5317, 2005.
8. SHELXTL v. 5.10, Structure Determination Software
Suite, Bruker AXS, Madison, WI, 1998.
REFERENCES
1. P. J. Stang and V. V. Zhdankin, Chem. Rev. 96, 1123
(1996).
2. P. J. Stang, J. Org. Chem. 68, 2997 (2003).
9. M. S. Chernov’yants, E. B. Podgornaya, A. I. Pyshchev,
and I. N. Shcherbakov, Zh. Obshch. Khim. 68, 822
(1998).
3. V. V. Zhdankin and P. J. Stang, Chem. Rev. 108, 5299
(2008).
4. M. S. Chernov’yants and A. O. Dolinkin, Zh. Strukt. 10. Yu. V. Zefirov and P. M. Zorkii, Usp. Khim. 64, 446
Khim. 51, 1211 (2010).
(1995).
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 2 2012