ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2006, Vol. 32, No. 11, pp. 771–776. © Pleiades Publishing, Inc., 2006.
Original Russian Text © Yu.V. Kokunov, Yu.E. Gorbunova, 2006, published in Koordinatsionnaya Khimiya, 2006, Vol. 32, No. 11, pp. 803–808.
Coordination Polymer of Ag Trifluoroacetate
with 2-Methylpyrazine: Synthesis and Structure
of [Ag(CF CO )(2-Me-Pyz)]
3
2
Yu. V. Kokunov and Yu. E. Gorbunova
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
Received March 24, 2006
Abstract—The [Ag(CF CO )(2-Me-Pyz)] complex (where 2-Me-Pyz is 2-methylpyrazine) was synthesized
3
2
and its structure was determined. The crystals are monoclinic, space group P2 /n, a = 12.440(2) Å, b =
1
3
3
2
.605(3) Å, c = 12.646(3) Å, β = 95.95(3)°, V = 1972.3(7) Å , ρ = 2.122 g/cm , Z = 8. The structure consists of the
polymer zigzag chains of [Ag(C H N )] united into a three-dimensional framework through (CF CO )
–
∞
–
5
6
2
3
2
anions.
DOI: 10.1134/S1070328406110017
The authors of [1, 2] suggested that coordination samples prepared as mineral oil mulls. IR spectrum of
polymers and supramolecular compounds could be complex I contains absorption bands characteristic of
synthesized from so-called secondary building units
–
2
–
1
the CF CO anion (1023, 1603, and 1745 cm ) and
3
(
SBU). By making use of such a building unit, i.e., sil-
–
1
ver triacetate dimer, Ag (CF CO ) , and pyrazine and 2-Me-Pyz (650, 1010, 1230, and 1580 cm ).
2
3
2 2
tetramethylpyrazine, the coordination polymers of the
The study of the thermal stability of the complex
showed that at 130°C, 29.3% of its mass is lost due to
removal of methylpyrazine molecule. The complete
composition [Ag(CF CO ) L] were synthesized (where
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2
L is pyrazine and tetramethylpyrazine). In these com-
+
pounds, pairs of Ag ions are connected by carboxylate
+
destruction of the complex with the formation of Ag O
bridges. In addition, the Ag ions coordinate neutral
2
N-containing ditopic ligands to give layered structures [3]. occurs at 230°C.
This work was devoted to the synthesis of
X-ray diffraction analysis was performed on a
CAD4 Enraf-Nonius diffractometer. Absorption cor-
rection was applied empirically by North–Philips algo-
rithm, by making use of two Ψ-scan curves. The struc-
ture was solved by the heavy-atom method and refined
by full-matrix least-squares method for all non-hydro-
gen atoms. The obtained abnormally high values of
thermal parameter for the F atoms of both independent
–
[
Ag(CF CO )(2-Me-êyz)] (I) (where 2-Me-Pyz is 2-
3
2
methylpyrazine, C H N ), and X-ray diffraction study
5
6
2
of its structure.
EXPERIMENTAL
Synthesis of [Ag(CF CO )(2-Me-êyz)]. Solutions of
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2
Ag(CF CO ) and 2-Me-Pyz were prepared in isopropyl
3
2
alcohol. The reaction was performed at the reagent molar CF
CO ions suggest their sufficiently high degree of
2
3
ratio of 1 : 1, i.e., Ag(CF CO ) (0.22 g, 1 mmol) and 2-
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2
disordering, which does not allow determination of
possible orientations of the F atoms. The H atoms were
localized from geometrical analysis and included in
refinement in the rider model with isotropic thermal
Me-Pyz (0.094 g, 1 mmol). The reaction mixture was
stored in the dark, and in three weeks, rhomboid crystals
of I were formed. The crystals were studied by the ele-
mental analysis, IR and X-ray diffraction methods.
2
parameters (for all H atoms, U = 0.08 Å ). All calcu-
eq
lations were carried out with SHELXS86 and
SHELXL93 programs.
For [Ag(CF CO )(C H N )]
3
2
5
6
2
anal. calcd. (%): Ag 34.28, N 8.89, C 26.67, H 1.90.
Ag33.60, N 8.00, C 28.90, H 2.50.
Crystallographic parameters and summary of data
collection for structure I are listed in Table 1; coordi-
nates of atoms and their thermal parameters are given in
Found (%):
IR spectra of the complex were recorded on a Table 2, selected bond lengths and bond angles are pre-
Nexus Fourier spectrometer at 200–4000 cm with sented in Table 3.
–1
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71
Kokunov
