Synthesis and study of thiocyanato(N)iodocuprates(I) and -argentates(I) of quaternary arsonium cations

Article abstract of DOI:10.1007/s11176-005-0301-3

The reactions of triarylalkylarsonium acetates with CuI and AgI in the presence of excess potassium thiocyanate yield the corresponding triarylalkylarsonium thiocyanato(N)iodocuprates(I) and -argentates(I). The composition, structure, and thermal behavior

Full text of DOI:10.1007/s11176-005-0301-3

Russian Journal of General Chemistry, Vol. 75, No. 5, 2005, pp. 697 699. Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 5, 2005,
pp. 738 741.
Original Russian Text Copyright
2005 by Gigauri, Kikalishvili, Kipiani, Khidesheli, Kutsiya.
Synthesis and Study of Thiocyanato(N)iodocuprates(I)
and -Argentates(I) of Quaternary Arsonium Cations
R. D. Gigauri, M. I. Kikalishvili, E. I. Kipiani, A. V. Khidesheli, and L. A. Kutsiya
Dzhavakhishvili Tbilisi State University, Tbilisi, Georgia
Received December 17, 2002
Abstract The reactions of triarylalkylarsonium acetates with CuI and AgI in the presence of excess
potassium thiocyanate yield the corresponding triarylalkylarsonium thiocyanato(N)iodocuprates(I) and
-argentates(I). The composition, structure, and thermal behavior (in the range 20 1000 C) of these com-
pounds were studied by chemical analysis, IR spectroscopy, conductometry, and differential thermal analysis.
Tetraalkyl(aryl)arsonium halides are excellent pre-
cipitants for both relatively simple [1] and complex
[2, 3] anions. In this connection, it was suggested [4]
that quaternary ammonium salts could be successfully
used as reagents for quantitative determination of
some elements capable of forming anionic complexes.
The reactions of soluble arsonium salts with anionic
complexes containing different acido ligands were not
studied previously. In this study we prepared mixed-
ligand anionic complexes of Cu(I) and Ag(I) with
quaternary arsonium cations and examined their struc-
ture and thermal behavior in the range 20 1000 C.
The compounds prepared are white finely crystal-
line substances insoluble in water, alcohol, and non-
polar organic solvents but soluble in dimethylform-
amide. Their composition and structure were deter-
mined by elemental analysis (see table) and physico-
chemical methods.
The ionic structure of the compounds was proved
by measuring the molar electrolytic conductivity of
their dilute solutions in dimethylformamide (the com-
pounds are insoluble in water). It is known [5, 6] that
the molar electrolytic conductivity in dimethylform-
amide of 1 1 ionic coordination compounds contain-
Definite amounts of CuI and AgI were dissolved in
an aqueous solution containing excess potassium thio-
cyanate. The resulting mixture was treated with the
filtrate from the reaction of equivalent amounts of
a triarylalkyl(alkenyl)arsonium iodide with lead(II)
acetate in aqueous alcohol. Precipitates formed imme-
diately; they were identified, using physicochemical
methods, as quaternary arsonium thiocyanato(N)iodo-
cuprates(I) and -argentates(I).
ing single-charged cations and anions varies from 60
1
to 90
62 77
1 cm2 mol . In our case, it varies within
1
1 cm2 mol
(see table), unambiguously
confirming that the compounds dissociate in DMF:
[Ar3AsR][M(NCS)I]
[Ar3AsR]+ + [M(NCS)I].
The structures of the compounds were studied by
IR spectroscopy. It is known [7, 8] that the thiocya-
nato group can coordinate with the metal via either N
or S atom to form a thiocyanato(N) or thiocyanato(S)
complex, respectively. Also, being potentially a bi-
dentate ligand, it can form a bridge between two metal
ions. The IR spectra (Fig. 1) show that the NCS
groups coordinate with the Cu and Ag atoms via N
atom. Indeed, the (CN) bands in the IR spectra of
[Ar3AsR][M(NCS)I] are observed at approximately
The target products are formed by the following
sequence of reactions:
MI + KSCN
K[M(NCS)I],
(1)
(2)
(3)
2[Ar3AsR]I + Pb(CH3COO)2 3H2O
PbI2 + 2[Ar3AsR]OCOCH3 + 3H2O,
[Ar3AsR]OCOCH3 + K[M(NCS)I]
[Ar3AsR][M(NCS)I] + CH3COOK.
1
2085 2100 cm , suggesting the isothiocyanate struc-
ture of the substances [9]. It should be noted, how-
ever, that in the spectra of [Ar3AsR][Ag(NCS)I] the
band at 2050 2090 cm corresponding to (CN) of
the NCS groups is slightly split, which may be due
to the packing effect in the crystals. The absorption
spectra of all the compounds contain absorption bands
originating from vibrations of phenyl groups and other
The overall reaction is as follows:
1
2MI + 2KSCN + 2[Ar3AsR]I + Pb(CH3COO)2 3H2O
PbI2 + 2[Ar3AsR][M(NCS)I] + 2CH3COOK + 3H2O,
Ar = C6H5 or m-CH3C6H4; R = CH3, C2H5,
or CH2=CHCH2; M = Cu or Ag.
1070-3632/05/7505-0697 2005 Pleiades Publishing, Inc.

698
GIGAURI et al.
1
2
4000
3000
2000
1500
1000 700 600 500 400
1
, cm
Fig. 1. IR spectra of allyltriphenylarsonium (1) thiocyanato(N)iodoargentate(I) and (2) thiocyanato(N)iodocuprate(I).
substituents at the As atom and benzene ring. These
bands are virtually the same as in the spectra of the
corresponding quaternary arsonium iodides [10, 11],
which also indicates that the quaternary arsonium
moiety remains essentially unchanged in going from
the iodides to thiocyanatoiodometallates.
of allyl thiocyanate (calculated for the elimination of
CH2=CH CH2SCN: 15.53%) with the formation of
CuI and As(C6H4 CH3-m)3, which apparently form a
complex. Thermolysis of this complex starts at 230 C
and is complete at 470 C.
In this range, there are several thermal effects
caused, apparently, by elimination of tri-m-tolylarsine
and its oxidation. The total weight loss is 53.0%. The
final thermolysis products were not identified.
The As CAlk bands are observed at about 620
1
625 cm , suggesting the sp3 hybridization of the As
atom [10].
The thermal stability of the thiocyanato(N)iodo-
Thus, an IR study showed that the copper(I) and
cuprates(I) and -argentates(I) was studied by thermo- silver(I) thiocyanate compounds prepared are actually
gravimetric analysis. The thermograms are similar. thiocyanato(N)iodocuprates(I) and -argentates(I). Ac-
Figure 2 shows as example the thermogravigram of
tri-m-tolylallylarsonium thiocyanato(N)iodocuprate(I).
It demonstrates a 16.0% weight loss in the range 120
230 C (Tmin 170 C) corresponding to the elimination
cording to thermogravimetric analysis, the Cu NCS
bond in the complex anion [Cu(NCS)I] is weaker
than the Cu I bond. Another evidence of the stability
of the Cu I bond is that, to dissolve MI (M = Cu,
Yields, melting points, molar electrolytic conductivities ( ), and elemental analyses of quaternary arsonium thiocyanato-
(N)iodocuprates(I) and -argentates(I) [Ar3AsR][M(NCS)I]
Found, %
Calculated, %
Yield,
%
Ar
R
mp, C
Formula
As
I
M
S
As
I
M
S
C6H5
m-CH3C6H4 CH3
C6H5 CH2=CH CH2 111 112 79.8 81.4 11.9 19.7 17.2 5.4 C22H20AgAsINS 11.7 19.8 16.8 5.0
m-CH3C6H4 CH2=CH CH2 105 106 83.8 67.3 11.3 18.5 16.1 4.8 C25H26AgAsINS 11.0 18.6 15.8 4.6
CH3
76 77 79.3 65.8 12.5 20.6 17.9 5.6 C20H18AgAsINS 12.2 20.6 17.5 5.2
54 83.3 76.6 11.7 19.4 16.8 5.4 C23H24AgAsINS 11.4 19.3 16.4 4.8
m-CH3C6H4 C2H5
C6H5 CH3
m-CH3C6H4 CH3
87 88 79.7 62.1 11.5 18.8 16.5 4.9 C24H26AgAsINS 11.1 18.9 16.1 4.7
132 133 73.3 78.8 13.4 23.1 11.4 5.9 C20H18AsCuINS 13.1 23.3 11.1 5.6
114 115 86.1 86.7 12.5 20.5 10.7 5.6 C23H24AsCuINS 12.2 20.7 10.3 5.2
C6H5
CH2=CH CH2 117
86.5 84.2 12.8 21.1 10.9 5.8 C22H20AsCuINS 12.6 21.3 10.6 5.3
m-CH3C6H4 CH2=CH CH2 118 119 87.2 72.5 11.9 20.0 10.3 5.4 C25H26AsCuINS 11.7 19.9 9.9 5.0
m-CH3C6H4 C2H5
68 69 84.6 69.3 12.2 20.0 10.5 5.5 C24H26AsCuINS 11.9 20.3 10.1 5.1
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 5 2005

SYNTHESIS AND STUDY OF THIOCYANATO(N)IODOCUPRATES(I)
699
30 ml of alcohol. A yellow precipitate of PbI2 formed
immediately; it was filtered off. The filtrate was added
with continuous stirring to a solution prepared by
dissolving 1.31 g of AgI in 40 ml of water in the pres-
ence of 4.86 g of potassium thiocyanate. The micro-
crystalline precipitate was left overnight in the mother
liquor, after which it was filtered off, thoroughly
washed with water and alcohol, and dried in a desic-
cator over phosphorus pentoxide and paraffin to con-
stant weight. Triphenylmethylarsonium thiocyana-
to(N)iodoargentate(I) was obtained as a colorless or
light grayish powder; yield 2.72 g, mp 76 77 C.
100
m, mg
320 380
340
470
425
80
60
DTA
DTG
470
370
230
185
120
170
410
40
20
TG
140
The other complexes were prepared similarly; their
physicochemical constants are given in the table.
0
REFERENCES
200
400
600
800
T, C
1. Abalonin, B.E., Chernokal’skii, B.D., Shagidul-
lin, R.R., Izosimova, S.V., Zykova, T.V., and
Kamai Gil’m, Zh. Obshch. Khim., 1970, vol. 40, no. 8,
p. 1812.
2. Gigauri, R.D., Doksopulo, E.P., Natidze, N.V., and
Maniya, M., Soobshch. Akad. Nauk Gruz. SSR, 1984,
vol. 115, no. 1, p. 77.
3. Chernokal’skii, B.D., Levenshtein, I.B., and Ka-
mai, G.Kh., Zh. Obshch. Khim., 1970, vol. 40, no. 1,
p. 148.
Fig. 2. Thermogram of tri-m-tolylallylarsonium thio-
cyanato(N)iodocuprate(I).
Ag), potassium thiocyanate was taken in an approxi-
mately ninefold excess relative to the stoichiometry.
Nevertheless, treatment of the resulting solutions with
quaternary arsonium acetates resulted in precipitation
of only monothiocyanate complexes, i.e., even under
these conditions the iodide ion was not displaced by
the thiocyanato group.
4. Gigauri, R.D., Tigishvili, Z.L., Indzhiya, M.A., Gur-
genidze, N.I., and Chernokal’skii, B.D., Zh. Obshch.
Khim., 1980, vol. 50, no. 11, p. 2514.
5. Peyronel, I., Malavasi, W., and Pignedoli, A., Spec-
trochim. Acta (A), 1982, vol. 38, no. 10, p. 1069.
6. Gigauri, R.D., Robakidze, N.Z., Indzhiya, M.A., and
Vachnadze, U.E., Zh. Obshch. Khim., 1997, vol. 67,
no. 1, p. 77.
7. Nakamoto, K., Infrared and Raman Spectra of In-
organic and Coordination Compounds, New York:
Wiley, 1986.
8. Kharitonov, Yu.Ya., Machkhoshvili, R.I., Metre-
veli, D.P., and Pirtskhalava, N.I., Koord. Khim., 1977,
vol. 3, no. 6, p. 897.
EXPERIMENTAL
The IR spectra were taken on a UR-20 spectrom-
1
eter in the range 400 3700 cm in KBr.
The molar electolytic conductivity of the com-
pounds in DMF was measured 25 C on an Impul’s
conductometer with a 1.5% accuracy. The tempera-
ture was kept constant with a 0.5 C accuracy. The
molar electrolytic conductivity was calculated by the
1
formula = 1000 /c [ 1 cm2 mol ], where and c
are the specific electrical conductivity and concentra-
tion of the solution, respectively.
The thermogravimetric analysis was performed
with a Paulik Paulik Erdey Q-1500D derivatograph
9. Machkhoshvili, R.I., Shalamberidze, T.V., and
Shchelokov, R.N., Zh. Neorg. Khim., 1983, vol. 28,
no. 5, p. 1213.
1
(heating rate 10 deg min in air, 0.1-g samples, Pt
crucible).
10. Tsentovskii, V.I., Chernokal’skii, B.D., Gigauri, R.D.,
Chachava, G.N., and Ugulava, M.M., Zh. Obshch.
Khim., 1973, vol. 43, no. 4, p. 837.
As starting compounds we used triarylalkyl(alken-
yl)arsonium iodides prepared by alkylation of sym-
metrical arsines according to [11] and CuI and AgI
prepared by the standard procedure [12].
11. Gigauri, R.D., Goderdzishvili, L.I., Chernokal’-
skii, B.D., Indzhiya, M.A., Sabin-Guss, I.A., and
Shatakishvili, T.N., Soobshch. Akad. Nauk Gruz. SSR,
1980, vol. 99, no. 3, p. 605.
Triphenylmethylarsonium thiocyanato(N)iodo-
argentate(I). A 1.06-g portion of lead(II) acetate was
dissolved in 40 ml of distilled water and treated with
2.5 g of triphenylmethylarsonium iodide dissolved in
12. Brauer, G., Handbuch der praparativen anorgani-
schen Chemie, Stuttgart: Ferdinand Enke, 1954.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 5 2005