ISSN 0036-0244, Russian Journal of Physical Chemistry A, 2008, Vol. 82, No. 1, pp. 119–121. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © V.L. Ivanov, V.A. Roznyatovskii, Yu.A. Ustynyuk, A.L. Buchachenko, 2008, published in Zhurnal Fizicheskoi Khimii, 2008, Vol. 82, No. 1, pp. 131–133.
PHOTOCHEMISTRY
AND MAGNETOCHEMISTRY
Photochemical Reactions of Di(naphthyl-1-methyl)mercury
in Various Solvents
V. L. Ivanov, V. A. Roznyatovskii, Yu. A. Ustynyuk, and A. L. Buchachenko
Faculty of Chemistry, Moscow State University, Moscow, 119992 Russia
e-mail: ivanov@photo.chem.msu.ru
Received October 10, 2006
Abstract—It was found that the photolysis of di(naphthyl-1-methyl)mercury (1) gives 1,2-dinaphthylethane
(2) in heptane and benzene solvents and 2 and 1-methylnaphthalene in isopropanol and acetonitrile. Irradiation
of 1 in carbon tetrachloride gives 2 and ClHgCH2C10H7 as primary reaction products, while the chloride is fur-
ther photolyzed to 2. Quantum yields of the photolysis of 1 are high and equal to unity almost for all solvents.
The chloride photodecomposition yield is an order of magnitude lower (0.1).
DOI: 10.1134/S0036024408010184
Organomercury compounds decompose upon irra- the spectral changes occurring during the photolysis
diation with light [1, 2]. The reaction primarily consists and from the absorbed light dose. Calculations were
of the C–Hg-bond dissociation with formation of radi- carried out using the Mathcad 2001i program. The light
cals and isolation of metallic mercury [3]. The photo- intensity absorbed by the sample was measured using
chemical reaction products depend on the solvent with an F4 photocell calibrated against a ferric oxalate acti-
which the radicals react. In the photolysis of di(n-triflu- nometer [6]. To determine the composition of reaction
1
13
oromethylbenzyl)mercury, we observed the magnetic mixture from the H and ë NMR spectra, 10 wt %
isotope effect on mercury nuclei [4]. In this work, we solutions of 1 in THF-d8 were additionally irradiated in
studied the photochemical reactions of di(naphthyl-1- sealed evacuated tubes.
methyl)mercury in various solvents. The use of this
compound with the aim of revealing magnetic isotope
RESULTS AND DISCUSSION
effect on mercury nuclei requires knowledge of the
photochemistry and quantum yields of the correspond-
ing reactions. Moreover, organomercury compounds
are known to be highly toxic, so that it is necessary to
know their photoinduced transformations and the cor-
responding chemical products.
During the irradiation of the solution of 1 with light
at 313 nm, its absorption spectrum changes due to pho-
tolysis (Fig. 1). The presence of isobestic points in the
spectra suggests that only one product is formed. The
spectral changes of 1 in heptane and benzene are simi-
lar, because, in both solvents, 1,2-dinaphthylethane (2)
is the photolysis product. In isopropanol and acetoni-
trile, apart from 2, 1-methylnaphthalene forms, which
EXPERIMENTAL
Di(naphthyl-1-methyl)mercury (1) was synthesized is identified by a band at 280 nm. Noteworthy is the
and purified as in [5]. The extinction coefficient of 1 in absence of the isobestic point near 290 nm in the tran-
benzene equals 17450 500 å–1 cm–1 at the absorption sient photolysis spectra of 1 in isopropanol and aceto-
maximum of 329.5 nm. The absorption spectra of the nitrile. This is caused by the fact that three species
solutions were recorded on a Shimadzu UV-2101PC absorb in this range: initial compound 1 and two photo-
spectrophotometer, and NMR spectra were taken on an products. The ratio of the yields of reaction products
AVANCE 600 (Bruker) spectrometer operating at a fre- (interaction of radicals with solvent and their dimeriza-
quency of 600 MHz for protons in a THF-d8 (Merck) tion) depends on the concentration of naphthylmethyl-
solution (99.9% deuterium), which was used without ene radicals, which changes during the photolysis.
additional purification. Irradiation of 2 × 10–4 M 1 in
The irradiation of 1 in carbon tetrachloride initially
various solvents was performed in 10 × 10-mm quartz
gives two products of photochemical reaction (Fig. 2a):
cells by light from a DRSh-500 mercury lamp equipped
2 and chloride ClHgCH2C10H7, which is further photo-
with a filter for selecting mercury line at 313 nm.
lyzed to 2. The presence of isobestic points in the rele-
To irradiate 1 with a 334-nm line in carbon tetra- vant transient photolysis spectra suggests that both
chloride, an SIF333 interference filter was used in con- products are formed in parallel in constant quantum
junction with an SZS-23 light filter. Quantum yields of yields. The absorption spectra of the photoreaction end
photochemical reactions were derived from the data on product (Fig. 2b) is similar to the spectra of the product
119
Ivanov
