ISSN 10703284, Russian Journal of Coordination Chemistry, 2015, Vol. 41, No. 2, pp. 69–75. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © I.N. Shcherbakov, S.I. Levchenkov, L.D. Popov, G.G. Aleksandrov, L.N. Etmetchenko, V.A. Kogan, 2015, published in Koordinatsionnaya Khimiya, 2015,
Vol. 41, No. 2, pp. 67–74.
Compartmental ligands are polydentate organic
compounds with a specific structure: the spatial
arrangement of their donor centers provides the for
mation of preorganized cavities for the coordination
of one or several metal ions. Binuclear complexes with
ligands of this type, in particular, bis(azomethines)
based on 1,3diaminopropan2ol, are convenient
models for studying the main factors that determine
the character and strength of exchange interactions
between the paramagnetic centers linked by hetero
bridges, because they assume a wide variation of both
the carbonyl component of the Schiff base and the
nature of the exogenic bridging ligand providing an
additional (to the alkoxide oxygen atom) exchange
channel [1–5]. Among copper(II) complexes of this
type, compounds, whose exchange fragment includes
the carboxylate or pyrazolate exogenic bridges, are
studied most completely, whereas compounds with
heterocyclic exogenic bridges of the NCN' type are
studied to a lesser extent.
In this work, we report the Xray diffraction analy
sis data for the binuclear copper(II)
ing the 6methoxypurinate (Mp) exogenic bridge with
), which is the condensation
product of 1,3diaminopropan2ol with 4hydroxy
3formylcoumarin, and the results of the experimental
study and quantumchemical simulation of the mag
netic exchange interaction in this complex.
Elemental analysis was carried out on a Perkin
Elmer 240C instrument.
H NMR spectra were
recorded in DMSO
on a Varian Unity 300 spec
trometer (300 MHz) using the pulse Fourier mode.
IR spectra were measured on a Varian Scimitar 1000
FTIR instrument in the range 400–4000 cm
samples prepared as suspensions in Nujol. The mag
netic susceptibility was determined by Faraday’s
method in the temperature range from 77.4 to 294 K.
The magnetic properties were interpreted in the
framework of Heisenberg–Dirac–Van Vleck isotropic
exchange model  using multidimensional fitting
according to the Bleaney–Bowers equation .
Synthesis of bis(azomethine)
A solution of
1,3diaminopropan2ol (6 mmol) in triethyl ortho
formate (7.5 mL) was added to a hot solution of
4hydroxycoumarin (12 mmol) in a dimethylforma
mide (DMF)–acetic acid (1 : 1) mixture (4 mL). The
resulting mixture was heated for 10 min until a yellow
precipitate was formed and left for 24 h. The precipi
tate was filtered off, washed with acetone, and recrys
tallized from a DMF–ethanol (3 : 2) mixture. The
yield was 2.14 g (82%), mp = 140°C.
Binuclear Copper(II) Complex with Bis(azomethine) Based
on 1,3Diaminopropan2ol and 4Hydroxy3Formylcoumarin:
Crystal Structure and Magnetic Properties
I. N. Shcherbakov
*, S. I. Levchenkov
, L. D. Popov
, G. G. Aleksandrov
L. N. Etmetchenko
, and V. A. Kogan
Southern Federal University, RostovonDon, 344104 Russia
Southern Scientific Center, Russian Academy of Sciences, RostovonDon, Russia
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
Received July 3, 2014
—The binuclear copper(II) complex [Cu
SO)] (Mp is 6methoxypurinate
anion) with the heterocyclic azomethine ligand, which is the condensation product of 1,3diaminopropan
2ol and 4hydroxy3formylcoumarin (H
L), is synthesized and structurally characterized (CIF file CCDC
no. 982199). The temperature dependence of the magnetic susceptibility is measured and shows a significant
exchange interaction of the antiferromagnetic type (2
= –348 cm
) in the compound. This sharply distin
guishes the new complex from the earlier studied compounds with a similar exchange fragment characteristic
of the ferromagnetic exchange. The antiferromagnetic exchange parameter is calculated by the quantum
chemical DFT method in the broken symmetry approximation.