ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2013, Vol. 58, No. 12, pp. 1446–1451. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © A.G. Beirakhov, I.M. Orlova, E.G. Il’in, S.G. Sakharov, L.V. Goeva, A.V. Churakov, M.D. Surazhskaya, Yu.N. Mikhailov, 2013, published in Zhurnal
Neorganicheskoi Khimii, 2013, Vol. 58, No. 12, pp. 1589–1594.
COORDINATION COMPOUNDS
Molybdenum(VI) Complexes with NꢀSubstituted Hydroxylamines
A. G. Beirakhov, I. M. Orlova, E. G. Il’in, S. G. Sakharov, L. V. Goeva,
A. V. Churakov, M. D. Surazhskaya, and Yu. N. Mikhailov
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
Received May 12, 2013
Abstract—New molybdenum(VI) complexes with Nꢀmonoalkylsubstituted hydroxylamines have been synꢀ
thesized and studied. The structure of [MoO2(C2H5NHO)2] and [MoO2(iꢀC3H7NHO)2], whose distinguishꢀ
ing feature is the bidentate chelate coordination of the ligand to molybdenum with the formation of the threeꢀ
membered NMoO chelate ring, has been determined by Xꢀray diffraction.
DOI: 10.1134/S003602361312005X
The presence of two active donating sites of differꢀ which are mainly represented by complexes with
ent characters in a hydroxylamine molecule allows us Nꢀdialkylsubstituted hydroxylamine derivatives.
to classify it with polydentate ligands, which are capaꢀ Such molybdenum(VI) complexes have certain bioꢀ
ble of adding to many complexꢀforming metals to activity [10] and can also be used in olefin oxidation
realize different coordination modes, namely,
processes [9].
In this work, we have studied molybdenum(VI)
complexes with Nꢀethylꢀ and Nꢀisopropylhydroxylꢀ
amines.
H3N O
H2N OH
NH2
O
M
M
M
1
2
3
EXPERIMENTAL
For example, hydroxylamine is coordinated to the
central ion via the nitrogen atom ( ) in platinum,
cobalt, and nickel complexes and via the oxygen atom
) in zinc, cadmium, calcium, barium, and mangaꢀ
nese complexes [1]. The bidentate coordination of
hydroxylamine and its derivatives ( ) is more rarely
Nitromethane, nitroethane (both from Acros
Organics), and 2ꢀnitropropane (from Aldrich) were
used in this study. The other reagents were of chemiꢀ
cally pure or pure for analysis grade.
Nꢀmethylhydroxylamine hydrochloride was syntheꢀ
sized by the following method [1]. To a solution of
nitromethane (50 g) and NH4Cl (30 g) in water
(400 mL), zinc dust (185 g) was added during 2–3 h
under continuous stirring, maintaining the temperaꢀ
1
(
2
3
encountered, mainly in complexes of Group V and VI
metal oxocations. This coordination mode, which was
first proved for complexes of uranyl [2] and tungꢀ
sten(VI) [3], was further also discovered in complexes
of molybdenum [4, 5], vanadium [6], and other metals
using Xꢀray diffraction. However, the formation
mechanisms of uranyl and molybdenum complexes
with hydroxylamine are different. Exchange reactions
are more typical for uranyl, whereas redox processes
with the resulting formation of mixed molybdeꢀ
num(IV) and vanadium(III) nitrosohydroxylaminate
complexes predominate for molybdenum(VI) and
vanadium(V). Similar reactions between molybdeꢀ
num(VI) compounds and Nꢀsubstituted hydroxyꢀ
lamines, which are weaker reducers than hydroxyꢀ
lamine, proceed without any change in the oxidation
state of the central atom to give mononuclear molybꢀ
denum dihydroxylaminates [MoO2(R1R2NO)2] [7–9]
ture within a range of 0–15°C. The mixture was then
filtered out, and the filtrate was neutralized by hydroꢀ
chloric acid and evaporated on a water bath until the
residue solidified under cooling. The residue was disꢀ
solved in ethanol, thereupon the solution was sepaꢀ
rated out of the ammonium chloride precipitate, and
ether was added. The settled precipitate was filtered
out and twice recrystallized from ethanol with the
addition of ether (1 : 1).
Nꢀethylꢀ and Nꢀisopropylhydroxylamine hydrochloꢀ
rides were synthesized by the same method from nitroꢀ
ethane and 2ꢀnitropropane (the reduction temperaꢀ
ture was 10–25 and 15–35°C, respectively). After neuꢀ
tralization with hydrochloric acid, the filtrate was
evaporated on a water bath until NH4Cl began to crysꢀ
tallize. The residue was diluted with ethanol and ether
(4 : 1) and evaporated again after ammonium chloride
was separated out. This operation was repeated several
times. Strong Nꢀethylꢀ and Nꢀisopropylhydroxylamꢀ
O
O
R2
R2
Mo
N
N
R1
,
R1
O
O
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