Some reactions and spectroscopic studies of tris(pentafluorophenyl) arsenic and -antimony(III and V) derivatives

Article abstract of DOI:10.1016/S0022-1139(03)00056-3

The reactions of tris(pentafluorophenyl)arsenic(III) with iodine monochloride, iodine monoazide, and dithiocyanogen yielded corresponding oxidative-addition products of the type (C₆F₅) ₃As(V)XY (X=I, Y=Cl, N₃; X=Y=NCS). The elemental sulphur also added oxidatively with tris(pentafluorophenyl)arsenic(III) yielding tris(pentafluorophenyl)arsine(V) sulphide. Some displacement reactions were also carried out to synthesize mixed pseudohalide derivatives of the type (C₆F₅)₃ M(N₃)NCS (M=As and Sb) and their insertion reactions were studied with phenyl isothiocyanate which yielded the corresponding 1,2-cycloaddition products, i.e. tetrazole-5-thiones. The compounds were characterized by elemental analysis, molar conductance, UV, IR and ¹⁹F NMR spectroscopic studies.

Full text of DOI:10.1016/S0022-1139(03)00056-3

Journal of Fluorine Chemistry 122 (2003) 165–170
Some reactions and spectroscopic studies of
tris(pentafluorophenyl)arsenic and -antimony(III and V) derivatives
Sanjeev K. Shukla, Ashok Ranjan, A.K. Saxena*
Defence Materials and Stores, Research and Development Establishment, G.T. Road, Kanpur 208013, India
Received 19 September 2002; received in revised form 9 December 2002; accepted 24 February 2003
Abstract
The reactions of tris(pentafluorophenyl)arsenic(III) with iodine monochloride, iodine monoazide, and dithiocyanogen yielded correspond-
ing oxidative-addition products of the type (C6F5)3As(V)XY (X ¼ I, Y ¼ Cl, N3; X ¼ Y ¼ NCS). The elemental sulphur also added
oxidatively with tris(pentafluorophenyl)arsenic(III) yielding tris(pentafluorophenyl)arsine(V) sulphide. Some displacement reactions were
also carried out to synthesize mixed pseudohalide derivatives of the type (C6F5)3M(N3)NCS (M ¼ As and Sb) and their insertion reactions
were studied with phenyl isothiocyanate which yielded the corresponding 1,2-cycloaddition products, i.e. tetrazole-5-thiones. The compounds
were characterized by elemental analysis, molar conductance, UV, IR and 19F NMR spectroscopic studies.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Pentafluorophenyl; Arsenic; Antimony; Synthesis; Spectroscopy
1. Introduction
2. Results and discussion
Despite a considerable interest in the chemistry of hydro-
carbon derivatives of arsenic and -antimony(III and V) [1–3],
very few studies have been devoted to the corresponding
fluorocarbon analogous [4–13]. Furthermore, compared to
perfluorophenylantimony(III and V) derivatives not much
attention has been given to similar perfluorophenylarseni-
c(III and V) derivatives [14–16]. As an electronic character
of aromatic rings is markedly changed by the replacement of
five nuclear hydrogen atoms for fluorine atoms, the chemical
and physical properties of the compounds are also changed
[14]. Thus, very striking differences have been observed in
phenyl and pentafluorophenyl substituted compounds just as
perfluoroalkyl groups alter the chemistry of alkyl groups [17].
Such intricacies always kindled interest of researchers to
study pentafluorophenyl derivatives of group 15 elements.
Thus, keeping our mind on the synthesis, reactions and
spectroscopic studies of perfluorophenyl group 15 deriva-
tives [6–13], it is considered worthwhile to investigate some
hitherto unstudied reactions (oxidative-addition, displace-
ment and insertion reactions) of tris(pentafluorophenyl)-
arsenic and -antimony(III and V) derivatives.
In general, compared to organoantimony(III and V) deri-
vatives organoarsenic(III and V) derivatives have been less
studied due to a highly toxic nature of the arsenic element
[18]. In chemical reactivity there is also marked difference
in both these two elements which may be due to an atomic
size difference between As and Sb elements. As our
general interest lies in the study of synthesis and reactions
of group 15 derivatives, we thought to study some reac-
tions, which were already carried out by us with orga-
noantimony derivatives [6]. Thus, some oxidative-addition,
displacement and insertion reactions of (C6F5)3As(III and
V) derivatives were studied herein along with some unstu-
died reactions of (C6F5)3Sb(III and V) derivatives for
comparison.
2.1. Oxidative-addition reaction
Oxidative-addition reactions are well known to synthesize
higher-valent derivatives of those compounds in which a
central metal atom has variable valency. Thus, a series
of oxidative-addition reactions of tris(pentafluorophenyl)-
arsenic(III) with ICl, IN3, (SCN)2 and Sn have been carried
out.
An iodine monochloride solution in acetonitrile was
added to (C6F5)3As at À10 8C with stirring under nitrogen
* Corresponding author. Tel.: þ91-512-2451759–78 Ext. 215 (O),
2402228 (R); fax: þ91-512-2450404.
E-mail address: sanshukla@lycos.com (A.K. Saxena).
0022-1139/$ – see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-1139(03)00056-3

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S.K. Shukla et al. / Journal of Fluorine Chemistry 122 (2003) 165–170
atmosphere, which yielded a corresponding oxidative-addi-
tion product:
1,2-cycloaddition products, i.e. tetrazole 5-thiones.
ðC6F5Þ3As þ ICl ! ðC6F5Þ3AsICl
(1)
The reaction of (C6F5)3As with IN3 (prepared from NaN3
and ICl) [19] and (SCN)2 (prepared by the reaction between
Pb(SCN)2 and Br2) [20] yielded corresponding oxidative-
addition products as shown below:
The consistency in the melting points of these cyclo-
addition products obtained after several crystallization,
excluded the possibility of mixtures of reactants. The molar
conductance values of the compounds were evaluated in
methanol (10À3 M solution), which were in the range of
16–29 cm2 OÀ1 molÀ1, showing their non-conducting beha-
viour in solution [23]. The molecular weights and the van’t
Hoff factor ‘i’ (0.97–1.04) determined cryoscopically in
nitrobenzene showed their monomeric nature. The elemental
analysis were also found satisfactory and within permissible
limits (Table 1).
ðC6F5Þ3As þ IN3 ! ðC6F5Þ3AsIN3
ðC6F5Þ3As þ ðSCNÞ2 ! ðC6F5Þ3AsðSCNÞ2
(2)
(3)
Reactions with dithiocyanogen (SCN)2 were performed in
the dark to circumvent the (SCN)2 polymerization in the
light.
Elemental sulphur was also found to add oxidatively to
(C6F5)3As in a refluxing benzene solution under dry nitrogen
atmosphere to give corresponding sulphides.
ðC6F5Þ3As þ Sn ! ðC6F5Þ3AsS
(4)
(C6F5)3AsS has also been obtained by passing a H2S gas
in an alcoholic ammonia solution of (C6F5)3AsCl2 in the
presence of triethylamine.
The molecular weight of the sulphide derivative deter-
mined cryoscopically in nitrobenzene indicated that it
existed in monomeric form. It may be worth mentioning
that tris(perfluoroalkyl)antimony and sulphur did not react
each other [21].
In these reactions no cleavage of the M–C bond has been
noticed compared to tetraorganometallic derivatives of
Group 14 (M ¼ Ge, Sn and Pb), where ICl and IN3 behaved
as electrophilic reagents and cleaved the metal–carbon
bond(s) [22].
2.4. IR spectra
IR spectra were recorded in KBr/CsI pellets in the range
of 4000–200 cmÀ1 and some of the characteristic absorption
bands of these derivatives are given in Table 2.
In pentafluorophenylantimony derivatives (6 and 9) char-
acteristic n(C–C) bands of C6F5 group were found as reported
for other pentafluorophenylantimony compounds and appe-
ared at 1641 ꢀ 7 (s), 1519 ꢀ 6 (vs) and 1480 ꢀ 5 (vs) cmÀ1
as well as n(C–F) absorption bands appeared at 1385 ꢀ 4 (s),
1289 ꢀ 3 (m), 1083 ꢀ 5 (vs) and 979 ꢀ 6 (vs) cmÀ1 [5].
In pentafluorophenylarsenic derivatives (1–5, 7 and 8)
characteristic n(C–C) bands of C6F5 group appeared com-
paratively at lower frequency, i.e. at 1620 ꢀ 6 (s), 1516 ꢀ 7
(vs) and 1473 ꢀ 7 (vs) cmÀ1 and n(C–F) absorption bands
appeared at 1380 ꢀ 3 (s), 1279 ꢀ 5 (m), 1078 ꢀ 4 (vs) and
2.2. Displacement reaction
969 ꢀ 8 (vs) cmÀ1
.
Tris(pentafluorophenyl)arsenic and -antimony azidoi-
sothiocyanates were prepared by a displacement reaction
of the corresponding metal iodoazides with freshly prepared
AgNCS (prepared by reaction of AgNO3 and NH4NCS) as
shown below:
The most prominent absorption in the infrared spectra
of the pentafluorophenylarsenic azide derivative 2 is the
asymmetric stretching frequency which was observed at
2133 cmÀ1. Though the asymmetric absorptions appeared
atahigherfrequency ascompared toPh3Sb(N3)2, othermodes
of vibrations, i.e. symmetric and bending, were not signifi-
cantly changed, suggesting the covalent nature of the deri-
vative [24]. The corresponding symmetric band which has
been reported to appear as a weak band (at ꢁ1275 cmÀ1) in
triorganoantimony azides (R ¼ alkyl or aryl) was observed at
1282 cmÀ1 [24]. Moreover, a weaker band observed at
663 cmÀ1 is assigned to the bending mode of the –N3 group.
The isothiocyanate group in compound 3 gives three
fundamental modes of vibrations due to n(C¼N), n(C–S)
and d(NCS) at 2058, 775 and 461 cmÀ1, respectively.
In the compounds 5 and 6 asymmetric stretching absorp-
tion bands of n(NCS) and n(N3) could not be observed
separately due to close proximities of both frequencies
ðC6F5Þ3MIN3 þAgNCSM¼Asð!5ÞorSbð6ÞðC6F5Þ3MðN3ÞNCSþAgI
In the present investigation it has been observed that the
iodine was replaced by an isothiocyanate group, which is in
contrast to our previous studies, where the iodine invariably
remained bonded to antimony, irrespective of the nature of
the metallic salt used [6].
2.3. Insertion reaction
Insertion reactions were carried out with the correspond-
ing triaryl M(V) iodoazides and -azidoisothiocyanates
(M ¼ As and Sb) with PhNCS, yielding corresponding

S.K. Shukla et al. / Journal of Fluorine Chemistry 122 (2003) 165–170
167
Table 1
Some physical and analytical data of tris(pentafluorophenyl)arsenic and -antimony(V) compounds
Compound
no.
Empirical formula
(molecular weight)
mp (8C)
Yield (%) LM (cm2 OÀ1 molÀ1) 10À3 M
solution in methanol
Analysis: found (%) (calc.) (%)
C
H
N
1
2
3
4
5
6
7
8
9
C18F15IClAs (738.44)
138–139
170 (d)
255 (d)
128
68
62
58
75
74
79
62
65
69
28.37
22.09
17.36
16.08
25.80
26.79
23.31
21.86
22.06
29.31 (29.28)
29.00 (29.02)
34.72 (34.70)
35.53 (35.55)
33.78 (33.75)
31.54 (31.56)
34.12 (34.11)
38.50 (38.49)
36.41 (36.39)
–
–
C
18F15IN3As (745.01)
C20F15S2N2As (692.26)
18F15SAs (608.16)
–
5.66 (5.64)
4.07 (4.05)
–
–
C
–
C19F15N4SAs (676.19)
C19F15N4SSb (723.02)
C25H5F15IN4SAs (880.20)
179–180
188
–
8.27 (8.29)
7.76 (7.75)
6.35 (6.36)
8.60 (8.63)
8.17 (8.16)
–
198
0.60 (0.57)
0.64 (0.62)
0.60 (0.59)
C
26H5F15N5S2As (811.38)
209
C26H5F15N5S2Sb (858.21)
264 (d)
Table 2
Characteristic IR absorption bands (cmÀ1) for tris(pentafluorophenyl)arsenic and -antimony(V) compounds
2
3
5
6
7
8
9
Assignments
2133
–
–
–
–
–
–
–
n
n
asym(N3)
asym(NCS)
–
2058
–
2079
–
2080
–
2064
1376
–
2068
1352
–
–
1282
–
1380
–
Exocyclic(C¼S)
–
1284
–
1281
–
n
sym(N3)
–
1261
1025
–
1265
1018
784
–
1240
1021
786
–
Cyclic N¼N–N
–
–
–
–
Ring skeletal
–
775
–
785
–
781
–
nsym(NCS)
d(N3)
d(NCS)
663
–
–
461
485
482
–
479
476
and appeared as a broad band at ꢁ2080 cmÀ1. A symmetric
IR absorption band due to n(N3) appeared in such derivatives
at 1282 ꢀ 2 cmÀ1. The n(CS) band also appeared at 783 ꢀ
2 cmÀ1 (w) in these derivatives.
The nature of N- or S-bonded thiocyanato derivatives
(3, 5 and 6) is better elucidated by the energy of bending
modes, d(NCS), which occur in regions 490–450 and 440–
400 cmÀ1, respectively [24]. In these derivatives d(NCS)
bands appeared at 461–485 cmÀ1, while no band was
observed between 440 and 400 cmÀ1, thereby excluding
any possibility of the presence of a S–Sb bond.
disappearance of nsym(N3) band at ꢁ1280 cmÀ1 and appear-
ance of other IR absorption bands due to tetrazole ring
(cyclic N3 at 1265–1240 cmÀ1 and exocyclic n(C¼S) at
1376–1352 cmÀ1), [10] confirmed the formation of insertion
products. Invariably in all insertion products a new band of
medium intensity appeared at 1021 ꢀ 4 cmÀ1, which may be
assigned to the skeletal vibrations of the tetrazole ring [25].
In pentafluorophenylarsenic sulphide derivative 4 stretch-
ing vibration n(As–S) appeared at 498 cmÀ1, which
appeared at a higher field compared to alkylarsenic sulphide
derivatives [n(As–S) at 484 cmÀ1] [24].
In the cycloaddition product 7 the absorption due to N3
group disappeared [nasym(N3) ꢁ 2133 cmÀ1, nsym(N3) ꢁ
1281] [24] and new absorption bands appeared due to cyclic
N¼N–N at 1261–1255 cmÀ1 and exocyclic (C¼S) at 1380–
1365 cmÀ1, respectively, [10] thus confirming the formation
of a tetrazole ring. The formation of azido adducts with
PhNCS through N- or S-centres also has been ruled out due
2.5. UV spectra
The UVabsorption spectra of the cyclic derivatives 7–9 in
methanol solutions exhibited absorption in the region l 260–
290 nm, similar to that exhibited by an authentic sample of
1-phenyl tetrazole-5-thione 10 and thus supported the for-
mation of tetrazole derivatives [26].
An additional support for the formation of the tetrazole
ring, acid hydrolysis of the compound 7 gave 1-phenylte-
trazole-5-thione 10 and (C6F5)3AsICl, mp 138–139 8C as
shown below:
to the absence of nasym(NCS) absorption at ꢁ2060 cmÀ1
.
But in the case of cycloaddition compounds 8 and 9 when
both –NCS and –N3 groups were present, after the insertion
reaction a strong band still persisting at 2066 ꢀ 2 cmÀ1
,
which may be attributed due to Sb–NCS group, [10] but

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S.K. Shukla et al. / Journal of Fluorine Chemistry 122 (2003) 165–170
2.6. 19F NMR spectra
10À3 M solution of the compounds was determined at
25 8C with a Khera DC610 Digital conductivity meter in
methanol.
The 19F NMR spectra of the compounds 1–9 were recorded
in CDCl3 using CF3COOH as a reference at 400 MHz. In
all pentafluorophenylarsenic compounds (1–5, 7 and 8) the
signals due to F4, F2,6 and F3,5 appeared at d À145:7 ꢀ 1:5,
À128 ꢀ 3 and À156:9 ꢀ 1 ppm, respectively and pentafluor-
ophenylantimony compounds (6 and 9) showed the signals
due to F4, F2,6 and F3,5 at d À149:4 ꢀ 1:3, À126:6 ꢀ 0:7
and À157:2 ꢀ 1:8 ppm, respectively. The F3,5 signals
appeared at higher field as compared to the F2,6 and F4
signals indicating the donation of electron from ortho and
para positions towards carbon attached to antimony atom
[11].
4.2. Representative synthetic procedures
4.2.1. Reaction of (C6F5)3As and ICl
A solution of iodine monochloride (0.325 g, 2 mmol) in
acetonitrile (50 ml) was added dropwise to a stirred solution
of (C6F5)3As (1.15 g, 2 mmol) in the same solvent (50 ml)
at À10 8C during 1 h. The reaction mixture was allowed
to attain room temperature and stirred further for 30 min to
ensure the completion of the reaction. Concentration of the
solution followed by the addition of petroleum-ether (40–
60 8C) afforded off-white crystalline solid (C6F5)3AsICl (1),
mp 138–139 8C; yield ꢁ1.0 g (68%); 19F NMR (400 MHz):
d ¼ À130:90 (d, F2,6) [J2,3ðHzÞ ¼ 20:54], À144.13 (t, F4),
À157.83 ppm (t, F3,5) [J3,4ðHzÞ ¼ 19:53].
3. Conclusion
The oxidative-addition reactions of interhalogen (ICl),
halopseudohalogen (IN3) and pseudohalogen [(SCN)2] pro-
ceeded in the similar way as the analogous phenyl deriva-
tives of arsenic and antimony.
The tris(pentafluorophenyl)arsenic(V)sulphide formation
is not so smooth and easy compared to triphenylarsine
derivatives, which further indicated that due to C6F5 ring
the central metal atom, i.e. arsenic feels more electron
density which slower down the reaction.
Insertion reactions of tris(pentafluorophenyl)arsenic and -
antimony with PhNCS proceeded easily and gave quantita-
tive yields compared to the analogous phenyl derivatives,
which may be attributed to the electron donor behaviour of
C6F5 rings compared to C6H5 rings.
4.2.2. Reaction of (C6F5)3As and IN3
A freshly generated solution of iodine azide (0.338 g,
2 mmol) in acetonitrile (50 ml) at À10 8C was added to a pre-
cooled (À10 8C) vigorously stirred solution of (C6F5)3As
(1.15 g, 2 mmol) in the same solvent (50 ml) during 15 min
under nitrogen atmosphere. The reaction mixture was stirred
for 1 h at initial temperature and then allowed to come at
room temperature. The solution was distilled under reduced
pressure (1.00 mm) and cooled overnight after adding pet-
roleum-ether (40–60 8C) (10 ml). A pale yellow crystalline
solid thus obtained was characterized as (C6F5)3AsIN3 (2),
mp 170 8C (d); yield 0.93 g (62%); 19F NMR (400 MHz):
d ¼ À130:21 (d, F2,6) [J2,3ðHzÞ ¼ 20:54], À144.90 (t, F4),
À157.32 ppm (m, F3,5) [J3,4ðHzÞ ¼ 19:53].
4. Experimental
4.2.3. Reaction of (C6F5)3As and (SCN)2
A freshly prepared solution of thiocyanogen (0.25 g,
2 mmol) in CCl4 (30 ml) was added to a stirred solution
of (C6F5)3As (1.15 g, 2 mmol) in the same solvent at À10 8C
during 15 min under nitrogen atmosphere. The reaction
mixture was subsequently stirred for 1 h and warmed to
room temperature. Removal of the volatiles under reduced
pressure (1.0 mm) afforded a pale yellow solid. After recrys-
tallization from ethanol it was characterized as (C6F5)3-
As(NCS)2 (3), mp 255 8C (d); yield 0.80 g (58%); 19F NMR
(400 MHz): d ¼ À130:12 (d, F2,6) [J2,3ðHzÞ ¼ 20:53],
À145.31 (t, F4), À157.20 ppm (m, F3,5) [J3,4ðHzÞ ¼ 19:54].
4.1. General experimental procedures
Solvents (AR Grade) were purified, dried and distilled
before use as per the literature methods [27]. (C6F5)3As [6],
(C6F5)3Sb [6], and (C6F5)3SbIN3 [6] were synthesized by
the reported methods. Silver thiocyanate was prepared by
the reaction of silver nitrate and ammonium thiocyanate.
Iodine azide and thiocyanogen were prepared by standard
methods and used when freshly prepared. Iodine mono-
chloride (Fluka) and phenyl isothiocyanate were used as
received.
IR spectra were recorded on a Pye Unicam SP3-300
spectrophotometer in the range 4000–200 cmÀ1 in the solid
state using KBr/CsI Pellets. 19F NMR spectra were recorded
on a JEOL JNM-400 NMR spectrometer in CDCl3 using
CF3COOH as a reference. UV spectra were recorded on
a Varian Cary-1000 spectrophotometer (l ¼ 220–400 nm)
in methanol. Molecular weights were determined
cryoscopically in nitrobenzene using a Beckman thermo-
meter of ꢀ0.01 accuracy. The molar conductance of a
4.2.4. Reaction of (C6F5)3As with elemental sulphur
A solution of (C6F5)3As (1.15 g, 2 mmol) in benzene
(50 ml) was refluxed with elemental sulphur (0.064 g,
2 mmol) for 8 h under nitrogen atmosphere. The solution
was concentrated and cooled overnight to afford an off
white crystalline solid (C6F5)3AsS (4), mp 128 8C; yield
0.91 g (75%);19F NMR (400 MHz): d ¼ À130:00 (d, F2,6
[J2,3ðHzÞ ¼ 20:54], À145.10 (t, F4), À157.00 ppm (t, F3,5
[J3,4ðHzÞ ¼ 19:53].
)
)

S.K. Shukla et al. / Journal of Fluorine Chemistry 122 (2003) 165–170
169
4.2.5. Synthesis of (C6F5)3Sb(N3)NCS (6)
with cold ethanol (25 ml). After rinsing with a little n-hexane,
the remaining solid was recrystallized with hot ethanol and
characterized as 1-phenyltetrazole-5-thione 10, yield 0.1 g
(56%), mp 148–149 8C ([10] mp 150 8C). UV: l 276 nm
([10] l 276 nm).
A solution of (C6F5)3SbIN3 (1.98 g, 2.5 mmol) and
freshly prepared AgNCS (0.58 g, 3.5 mmol) in acetonitrile
(100 ml) was stirred vigorously for 4 h at room temperature
(ꢁ25 8C) and further refluxed for 1 h. The solution
was filtered to remove AgI and unreacted AgNCS and the
filtrate was concentrated to 25 ml under vacuum (0.01 mm).
To the concentrated solution, petroleum-ether (40–60 8C)
(15 ml) was added and the mixture was cooled overnight
to afford white, moisture sensitive crystals identified as
(C6F5)3Sb(N3)NCS (6), mp 188 8C; yield 1.43 g (79%);
19F NMR (400 MHz): d ¼ À126:00 (d, F2,6) [J2,3ðHzÞ ¼
20:63], À148.13 (t, F4), À155.40 ppm (m, F3,5) [J3,4ðHzÞ ¼
19:60].
Similarly (C6F5)3As(N3)NCS (5) was prepared by the
reaction of (C6F5)3AsIN3 with AgNCS, 19F NMR
(400 MHz): d ¼ À125:28 (d, F2,6) [J2,3ðHzÞ ¼ 20:53],
À144.90 (t, F4), À156.00 ppm (m, F3,5) [J3,4ðHzÞ ¼ 19:53].
These compounds (5 and 6) were also prepared without
separating iodoazide derivatives and in situ converted into
azidoisothiocynato derivatives.
The ethanol solution on slow evaporation yielded
(C6F5)3AsICl, mp 138–139 8C.
Acknowledgements
One of the authors (SKS) is thankful to DRDO, New Delhi
for the award of Senior Research Fellowship. We are
thankful to the Director, DMSRDE, Kanpur for providing
laboratory facilities and permission to publish the work.
References
[1] G.O. Doak, L.D. Freedman, Organometallic Compounds of Arsenic,
Antimony and Bismuth, Wiley/Interscience, New York, 1970.
[2] J.P. Crow, W.R. Cullen, Organic compounds of arsenic, antimony
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Chemistry, M.T.P. International Review of Science, Ser. 1, vol. 4,
Butterworths, London, 1972, p. 383.
4.2.6. Insertion reaction of (C6F5)3AsIN3 with PhNCS
An equimolar mixture of (C6F5)3AsIN3 (0.745 g,
1.0 mmol) and PhNCS (0.135 g, 1.0 mmol) was heated at
110 8C for 4 h. The resulting brown viscous mass was
extracted with sodium dried n-hexane to afford 1-phenyl-
4-[tris(pentafluorophenyl)arsenic] iodo tetrazole-5-thione 7,
mp 198 8C; yield 0.55 g (62%); 19F NMR (400 MHz):
d ¼ À125:90 (d, F2,6) [J2,3ðHzÞ ¼ 20:54], À147.20 (t, F4),
À155.90 ppm (m, F3,5) [J3,4ðHzÞ ¼ 19:54].
[3] Y.Z. Huang, Z.L. Zhou, Antimony and bismuth, in: A. Mckillop
(Ed.), Comprehensive Organometallic Chemistry-II, vol. 11, Elsevier,
Oxford, 1995, pp. 487–513, and references therein.
[4] A. Otero, P. Royo, J. Organomet. Chem. 154 (1978) 13–19.
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101–106.
[6] P. Raj, A.K. Saxena, K. Singhal, A. Ranjan, Polyhedron 4 (2) (1985)
251–258, and references therein.
[7] P. Raj, A.K. Aggarwal, A.K. Saxena, J. Fluorine Chem. 42 (1989)
163–172.
4.2.7. Insertion reaction of (C6F5)3Sb(N3)NCS with PhNCS
An equimolar molar mixture of (C6F5)3Sb(N3)NCS
(0.723 g, 1 mmol) and PhNCS (0.135 g, 1 mmol) was heated
at 90 8C for 2 h. The resulting brown viscous mass was
extracted with sodium dried n-hexane to afford 1-phenyl-4-
[tris(pentafluorophenyl)antimony isothiocyanato] tetrazole-
5-thione 9, mp 264 8C (d); yield 0.59 g (69%); 19F NMR
(400 MHz): d ¼ À127:30 (d, F2,6) [J2,3ðHzÞ ¼ 20:60],
À150.60 (t, F4), À159.00 ppm (m, F3,5) [J3,4ðHzÞ ¼ 19:61].
Similar reaction of (C6F5)3As(N3)NCS (0.676 g, 1 mmol)
with PhNCS (0.135 g, 1 mmol) resulted in the formation of
1-phenyl-4-[tris(pentafluorophenyl) arsenic isothiocyanato]
tetrazole-5-thione 8, 19F NMR (400 MHz): d ¼ À125:00
(d, F2,6) [J2,3ðHzÞ ¼ 20:54], À145.00 (t, F4), À157.42 ppm
(m, F3,5) [J3,4ðHzÞ ¼ 19:53].
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