STRUCTURE AND STABILITY OF QUATERNARY AMMONIUM INTERHALIDES
581
1
The H NMR spectra (solutions in CD OD and
3. Zelikman, V.M. and Smirnov, V.V., Zh. Obshch.
Khim., 1994, vol. 64, no. 10, p. 1672.
3
CDCl ) were recorded on a Bruker DPX-250 spec-
3
trometer.
4
. Gol’eva, V.E., Chernov’yants, M.S., and Py-
shchev, A.I., Zh. Fiz. Khim., 2001, vol. 75, no. 8,
p. 1383.
Quantum-chemical calculation procedure. Since
the donor acceptor interactions (their wide variety
is extensively studied in numerous recent calculation
works [20 22]), apparently, play a decisive role in
the gas-phase stabilization of the hypervalent systems
in question, correct description of these interactions
requires adequate level of quantum-chemical calcula-
tions [20, 23, 24]. Taking into account that the sys-
tems contain several heavy atoms, we chose the basis
sets RHF/3-21G, RHF/HW, and MP2/HW [25 27];
calculations in these basis sets gave nicely consistent
results for all the complexes.
5
6
. Wang, Y.Q., Acta Crystallogr. (C), 1999, vol. 55,
no. 9, p. 1503.
. Podgornaya, E.B., Chernov’yants, M.S., Shcherba-
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999, vol. 69, no. 1, p. 109.
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1
8
. Intermolecular Interactions: From Diatomics to Bio-
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All the calculations were performed with a Pentium
III-550 computer using GAMESS software [28]. The
initial geometry optimization was performed by the
restricted Hartree Fock method (RHF) in the 3-21G
basis [25] and in the HW pseudopotential basis [25].
The RHF results were used as starting in the calcula-
tions taking into account the electron correlation ac-
cording to the second-order Møller Plesset perturba-
tion theory (MP2). The geometries of molecular struc-
tures corresponding to stationary points on the poten-
9
. Cammi, R. and Tomasi, J., J. Comput. Chem., 1995,
vol. 16, no. 11, p. 1449.
1
1
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tial energy surface were optimized to the gradient of
p. 441.
5
1
0
au/bohr. The matrices of force constants were
1
1
3. Mehta, G. and Uma, R., Chem. Commun., 1998,
calculated numerically using the GAMESS program.
vol. 16, p. 1735.
All the energies of complexation ( E ) and donor
1
4. Sutton, L.E., Tables of Interatomic Distances and Con-
figurations in Molecules and Ions, London: Chem.
Soc., 1965, p. M93; 1958, p. M52S.
acceptor X I bonds ( E ) were calculated without
2
2
taking into account the superpositional error, as the
differences between the total energies of the com-
plexes and their isolated components. The total ener-
gies of the ions used for estimating the interaction
energies in the complexes were found by the geometry
optimization with the starting parameters correspond-
ing to the conformations of the components in the
associates.
1
5. Popov, A.I., Halogen Chem., 1967, vol. 1, no. 2,
p. 133.
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vol. 3, no. 1, p. 133.
1
1
1
7. Huheey, J.E., Anorganische Chemie. Prinzipen von
Struktur und Reaktivitat, Berlin: De Gruyter, 1988.
ACKNOWLEDGMENTS
8. Mulliken, R.S., Chem. Phys., 1955, vol. 23, pp. 1833,
The study was financially supported by the Russian
Foundation for Basic Research (project no. 00-03-
1
841, 2338, 2343.
9. Chernov’yants, M.S., Podgornaya, E.B., Py-
shchev, A.I., and Shcherbakov, I.N., Zh. Obshch.
Khim., 1998, vol. 68, no. 5, p. 822.
3
2694a). The authors are also sincerely grateful to
A.I. Pyshchev for the synthesis and submission of the
compounds studied in this work.
2
0. Minyaev, R.M., Zh. Fiz. Khim., 2000, vol. 74, no. 1,
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 73 No. 4 2003