NMR study of the interaction of tin(II) and antimony(III) fluorides with phosphorus chlorides

Article abstract of DOI:10.1023/A:1016241025898

Reactions of SnF₂ and SbF₃ with POCl₃ and PCl₅ in acetonitrile were studied by ¹⁹F, ³¹P, and ¹¹⁹Sn NMR. Tetrahedral compounds POF₂Cl and POF ₃ form in the r

Full text of DOI:10.1023/A:1016241025898

Russian Journal of Coordination Chemistry, Vol. 28, No. 7, 2002, pp. 461–463. Translated from Koordinatsionnaya Khimiya, Vol. 28, No. 7, 2002, pp. 493–496.
Original Russian Text Copyright © 2002 by Kokunov, Ershova, Razgonyaeva.
NMR Study of the Interaction of Tin(II) and Antimony(III)
Fluorides with Phosphorus Chlorides
Yu. V. Kokunov, M. M. Ershova, and G. A. Razgonyaeva
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
Received September 18, 2001
Abstract—Reactions of SnF2 and SbF3 with POCl3 and PCl5 in acetonitrile were studied by 19F, 31P, and 119Sn
NMR. Tetrahedral compounds POF2Cl and POF3 form in the reaction with POCl3. Interaction of SnF2 and SbF3
with PCl5 yields higher (in terms of fluorine) octahedral complexes [PF5 · MeCN] and [PF6]–. In all cases, flu-
orine-free phosphorus compounds are found in the acetonitrile solution.
Tin(II) difluoride and antimony(III) trifluoride are dissolved under thorough stirring, indicating the onset
fluorine donors in reactions with tin(IV) [1], titanium of the reaction. However, even before full dissolution of
[2], niobium [3], and tantalum [4] halides. It has been fluorides, crystals precipitated. Acetonitrile solutions
found that their reactions with metal chlorides yield were removed from undissolved fluorides and new sol-
octahedral fluoride and fluorochloride complexes.
ids and studied by NMR.
Neutral phosphorus(V) fluorochloride compounds
have the structure of a trigonal bipyramid; they have
been prepared by chlorinating the corresponding phos-
phorus(III) fluorochlorides [5]. To synthesize higher
fluorides, for example, PClF4, the reaction between
PCl2F3 and SbF3 was used in [6]. Mixed octahedral
anions of the [PFnCl6 – n]– composition have been pre-
pared by redistributing ligands between PCl5 and PF5 in
acetonitrile (MeCN). The compositions and structures
of the complexes were determined using 19F and 31P
NMR in [7, 8].
According to the 19F and 31P NMR spectra, after
reacting SnF2 and SbF3 with POCl3, the main com-
pounds in solutions are POCl3, POF2Cl, and a small
19
31
quantity of POF3 (parameters of the F and P NMR
spectra are given in the table). In addition, the [PF6]– ion
appears in the solution (31P NMR spectrum: septet with
δ = –143.3 ppm and J
= 709 Hz, 19F spectrum:
31P–19
F
doublet with δ = –71.4 ppm and J
= 709 Hz). The
F
31P–19
[PF6]– ion seems to form due to the admixture of PCl5
The purpose of this work was to study the interac-
tion of SnF2 and SbF3 with POCl3 and PCl5 in MeCN
and to determine the compositions of the products by
19F and 31P NMR.
SnF2 was prepared according to [9]; reagent grade
SbF3 and PCl5 and pure grade POCl3 were used. Aceto-
nitrile was dried by repeated holding over P2O5 fol-
lowed by distillation.
NMR spectra were recorded on a Bruker AC-200
spectrometer at room temperature. Chemical shifts
were measured relative to CFCl3 (19F) or 85% H3PO4
(31P).
in POCl3. The low-intensity doublet at –19.5 ppm with
19
J
= 1186 Hz also appears in the F NMR spec-
31P–19
F
trum (no corresponding signal being observed in the 31P
spectrum). The 19F spectra show no signals of fluorine
atoms bonded to Sn(II). At the same time, single signals
appear in the 119Sn NMR spectra in the –690 to –760 ppm
range. This indicates that the solutions contain poly-
meric cationic Sn(II) complexes with bridging fluorine
atoms.
When SbF3 was used as a fluorinating agent, a wide
19
signal was observed at –86 ppm in the F spectra, in
addition to the signals of fluoride phosphorus com-
pounds, and was assigned to the Sb(III) fluorine-con-
taining compounds.
It is known that SnF2 and SbF3 are poorly soluble in
MeCN. This is why solid fluorides were added to ace-
tonitrile solutions of POCl3 and PCl5 in the experiments.
The initial molar ratio of the reagents SnF2(SbF3) :
POCl3(PCl5) was varied from 1 : 2 to 2 : 1. Reactions
were carried out at both room temperature and the tem-
perature of liquid nitrogen. In the latter case, the aceto-
nitrile solutions of POCl3 or PCl5 were frozen in liquid
nitrogen, solid fluorides were added, and the reaction
mixtures were gradually heated. In all cases, fluorides
In the reaction of SnF2 with PCl5 (SnF2 : PCl5 = 1 : 2
in MeCN), PF5 · MeCN predominantly forms in the
solution (31P NMR spectrum: sextet with δ = –141.2 ppm
and J
= 777Hz, 19F NMR spectrum: doublet at
31P–19
F
−59.3 ppm with J
= 778 Hz). The shape of the
31P–19
F
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(a)
220
180
140
100
60
20
–20
–60
–100
–140
–180
(b)
–220 δ, ppm
–25
–30
–35
–40
–45
–50
–55
–60
–65
–70
–75
–80
–85
–90
–95
–100 –105
δ, ppm
31
19
Fig. 1. The (a) P and (b) F spectra of the products of interaction between SnF and PCl in acetonitrile.
2
5

NMR STUDY OF THE INTERACTION OF TIN(II) AND ANTIMONY(III) FLUORIDES
463
19F and 31P NMR spectra of POFnCl3 – n compounds in ace-
tonitrile
spectra indicates that the fluorine atoms in the PF5 ·
MeCN complex are equivalent.
In addition, signals at 6.4 and 220.5 ppm are
observed in the 31P NMR spectrum. It is known that
[PCl6]– and [PCl4]+ ionic forms occur in solutions of
phosphorus pentachloride [10]. According to [8, 11],
[PCl4]+ reacts with MeCN to yield phosphonitrile com-
pounds producing 31P signals at 82 and 2.5 ppm. These
compounds tend to eliminate PCl3, whose signal is
observed in the weakest field (217 ppm) [8, 12]. There-
fore, the signal at 220.5 ppm is assigned to PCl3 and the
signal at 6.4 ppm should be assigned to the product of the
reaction between [PCl4]+ and MeCN or to POCl3 present
in PCl5 as an admixture or produced in hydrolysis.
Com-
31
δ(19F), ppm
δ( P), ppm
J
, Hz
J
F , Hz
31P–19
31P–19
F
pound
POCl3
POF2Cl
POF3
5.9
–22.9
–33.6
–82.2
–87.8
986
984
1068
1064
Therefore, when SnF2 and SbF3 are used as fluorine
donors in the reaction with POCl3, POF2Cl and POF3
are mainly formed. The above fluorides react with PCl5
in acetonitrile to yield higher phosphorus complexes
An increase in the solid SnF2 : PCl5 initial ratio in [PF6]– and [PF5 · MeCN]. No mixed fluorochloride
complex anions of the [PFnCl6 – n]– composition were
found. The reaction of SnF2 and SbF3 with POCl3 and
PCl5 in MeCN under the indicated conditions does not
result in the complete conversion of phosphorus chlo-
ride forms into fluorochloride or fluoride forms. In all
cases, the NMR spectra show signals due to the fluo-
rine-free phosphorus compounds.
acetonitrile up to 1 : 1 causes changes in the 19F and 31P
NMR spectra of the solutions (figure). In addition to the
signals at 220.7 and 6.6 ppm, the 31P NMR spectrum
shows a septet at –143.3 ppm with J
= 709 Hz
31P–19
F
assigned to the [PF6]– anion and two low-intensity quar-
tets at δ = –33.9 ppm with J = 1068 Hz (POF3)
31P–19
F
and at 104.1 ppm with J
= 1398 Hz. The latter
F
31P–19
ACKNOWLEDGMENTS
multiplet signal was assigned to PF3 on the basis of the
values of the chemical shift and spin–spin coupling
constant. These multiplet signals correlate with dou-
This work was supported by the Russian Foundation
for Basic Research, project nos. 00-03-32580 and
00-15-97432.
blets at δ = –71.4 ppm with J
= 707 Hz ([PF6]–),
31P–19
F
at −87.6 ppm with J
= 1068 Hz (POF3), and at
F
= 1404 Hz (PF3) in the 19F
31P–19
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RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 28 No. 7 2002