Russian Journal of Coordination Chemistry, Vol. 26, No. 12, 2000, pp. 892–893. Translated from Koordinatsionnaya Khimiya, Vol. 26, No. 12, 2000, pp. 949–950.
Original Russian Text Copyright © 2000 by Korshunov, Bicherov, Garnovskii.
LETTERS
TO THE EDITOR
New Ambidentate Ligands—Derivatives
of 1,2-Benzothiazine-1,1-Dioxide
O. Yu. Korshunov, A. V. Bicherov, and A. D. Garnovskii
Institute of Physical and Organic Chemistry, Rostov State University, pr. Stachki 194/3, Rostov-on-Don, 344104 Russia
Based on 1,2-benzothiazine-1,1-dioxide (HL1) [1] selective isomers1 [2, 3], i.e., chelate compounds I and
and with regard to its ambidentate nature, two regio- II, can be obtained.
M/2
H
OH Ph
O
O
O
S
O
O
Ph
Ph
N
S
N
O
N
S
R
R
M/2
O
O
O
O
O
R = H(HL1), CH3(HL2)
(I)
M = Zn, Ni; R = H, CH3
(II)
M = Zn, Ni
HL2 should be considered as a model compound structure of the coordination polyhedron that is also
forming only chelates of type I.
typical of other nickel β-diketonates [4].
Note in conclusion that the data we obtained are of
great importance in understanding possible methods of
competitively binding metals with medicines which are
hetercyclic derivatives of 1,2-benzothiazine-1,1-di-
oxide (pyroxycam, isoxycam etc.); this should sustain
the interest of researchers [5–7].
The complexes of the ML2 composition (as follows
from the results of the elemental analysis) were synthe-
sized upon heating methanol solutions containing
0.01 mol of HL1 or HL2 and 0.005 mol of nickel or zinc
acetate for a short time. These chelates were obtained
for the first time. They are crystalline substances with
m.p. above 250°C; ZnL12 melts at 224°C.
ACKNOWLEDGMENTS
1
According to IR and H NMR spectroscopic data,
The authors are grateful to V.P. Kurbatov for mea-
suring magnetic moments and to G.S. Borodkin for
recording 1H NMR spectra.
the chelates under study exhibit structure I with a coor-
dination core like that of β-diketonate.
In the IR spectra of these compounds, the bands in
the range 3200–3300 cm–1, which are due to the stretch-
ing vibration of the OH group of HL1 or HL2, are absent
while the band due to the NH–SO2 fragment of HL1 at
3400 cm–1 remains unchanged.
This work was supported by the Russian Foundation
for Basic Research, project no. 00-15-97320.
REFERENCES
The 1H NMR spectra of free ligands exhibit the pro-
ton signals of the OH group at 15.80 ppm (HL1) or
16.00 ppm (HL2). These are not observed in the spectra
of zinc complexes. However, the 1H NMR spectrum of
ZnL12 retains the signal at 9.73 ppm due to the proton
of the NH group in the HL1 ligand.
1. Abe, K., Yamamoto, S., and Matsui, K., J. Pharm. Soc.
Jpn., 1956, vol. 76, p. 1058.
2. Von Selewzki, A., Stereochemistry of Coordination
Compounds, Chichester: Wiley, 1996.
3. Garnovskii, A.D., Vasil’chenko, I.S., and Garnovskii, D.A.,
Sovremennye aspektyu sinteza metallokompleksov.
(Modern Aspects of Metallocomplexes Synthesis), Ros-
tov-on-Don: LaPO, 2000.
The data of the magnetochemical study also favor
the structure I. The values of magnetic moments for
1
NiL12 and NiL22 equal to 3.08 and 3.25 µB, respectively,
This type of isomerism is produced by the ambidentate ligands
which form complexes with differing localization of the coordina-
tion bond.
agree with the intermolecular-associated octahedral
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