Reactions of tetracyclic tetraaminophosphoranes with dichloroperfluoro cyclic and acyclic alkenes and halo compounds

Article abstract of DOI:10.1016/S0022-1139(98)00268-1

Cyclenphosphorane was reacted with 1,2-dichlorotetrafluorocyclobutene-1, 1,2-dichlorohexafluorocyclopentene-1, 1,2-dichlorooctafluorocyclohexene-1, iodopentafluorobenzene, 2-iodo-1,1,1-trifluoroethane, and 2,3-dichlorohexafluorobutene-2 in the presence of triethylamine at room temperature in tetrahydrofuran to form monochlorotetrafluorocyclobutenylcyclenphosphorane, monochlorohexafluorocyclopentenylcyclenphosphorane, monochlorooctafluorocyclohexenylcyclenphosphorane, pentafluorophenylcyclenphosphorane, 1,1,1-trifluoroethylcyclenphosphorane, and 2-chlorohexafluorobut-2-enylcyclenphosphorane in 70-80% yields, respectively. Cyclamphosphine oxide reacted with dichloroperfluorocyclic alkenes in the presence of triethylamine in chloroform to form N-(chlorotetrafluorocyclobutenyl)cyclamphosphine oxide, N-(chlorohexafluorocyclo-pentyl)cyclamphosphine oxide and N-(chlorooctafluorocyclohexenyl)-cyclamphosphine oxide in ~50% yields, respectively. These moisture sensitive cyclamphosphine oxide derivatives are stable and are soluble in CHCl₃, CH₃CN and DMSO.

Full text of DOI:10.1016/S0022-1139(98)00268-1

Journal of Fluorine Chemistry 92 (1998) 147±151
Reactions of tetracyclic tetraaminophosphoranes with
dichloroper¯uoro cyclic and acyclic alkenes
and halo compounds
O.D. Gupta1, Robert L. Kirchmeier, Jean'ne M. Shreeve*
Department of Chemistry, University of Idaho, Moscow, ID 83843, USA
Received 1 June 1998; accepted 11 August 1998
Abstract
Cyclenphosphorane was reacted with 1,2-dichlorotetra¯uorocyclobutene-1, 1,2-dichlorohexa¯uorocyclopentene-1, 1,2-dichloroocta-
¯uorocyclohexene-1, iodopenta¯uorobenzene, 2-iodo-1,1,1-tri¯uoroethane, and 2,3-dichlorohexa¯uorobutene-2 in the presence of
triethylamine at room temperature in tetrahydrofuran to form monochlorotetra¯uorocyclobutenylcyclenphosphorane, monochlorohexa-
¯uorocyclopentenylcyclenphosphorane, monochloroocta¯uorocyclohexenylcyclenphosphorane, penta¯uorophenylcyclenphosphorane,
1,1,1-tri¯uoroethylcyclenphosphorane, and 2-chlorohexa¯uorobut-2-enylcyclenphosphorane in 70±80% yields, respectively. Cyclamphos-
phine oxide reacted with dichloroper¯uorocyclic alkenes in the presence of triethylamine in chloroform to form N-(chlorotetra¯uoro-
cyclobutenyl)cyclamphosphine oxide, N-(chlorohexa¯uorocyclo-pentyl)cyclamphosphine oxide and N-(chloroocta¯uorocyclohexenyl)-
cyclamphosphine oxide in ꢀ50% yields, respectively. These moisture sensitive cyclamphosphine oxide derivatives are stable and are
soluble in CHCl3, CH3CN and DMSO. # 1998 Elsevier Science S.A. All rights reserved.
1. Introduction
atoms in the polycyclic structure [12±17]. In the case of
2A only the phosphorane tautomer is observed [12]. This
is in contrast to the bis(borane) adducts formed by
cyclamphosphorane (2B) where both tautomers, phosphor-
ane and phosphine, are formed. It appears that the initial
equilibria observed by Atkins and Richman [2,3] play an
important role in determining the chemistry of the cyclic
tetraaminophosphoranes but subsequent reaction conditions
can override the equilibria that are a function of ring size.
However, unlike the larger macrocyclicamine phosphoranes,
2A exists only as the closed tautomer in solution as well as in
solid and gas phases.
Molecules that contain pentacoordinate phosphorus
bonded to cyclic tetraamino moieties were ®rst reported
in 1977 [1±3], followed somewhat later by methoxy, thio-
methoxy [4] and cyclenphosphonium salts [5]. The reactiv-
ity of these molecules should exhibit novel patterns because
of (1) the presence of lone pairs on the nitrogen atoms, (2)
the likelihood of the presence of a labile P±X bond (and
potentially labile P±N bonds), and (3) the fact that an
equilibrium can exist in solution between the phosphorane
and phosphine forms when at least two of the N±N links are
propyl or higher. This behavior was attributed to bonding
con®guration changes due to ring size [1]. Each of these
patterns has been observed. CyclenPH (2A), when irra-
diated, gives the tetra-coordinate phosphoranyl radical,
*
cyclenP ([6±9]. The lithiated form of 2A with cyclenPF
yields cyclenP-Pcyclen [10,11]. 2A reacts with diborane to
afford cyclenphosphorane-bis(borane) which suggests un-
usually strong basicity of the P-bonded apical nitrogen
Attempts to isolate the open form 2A1 by coordination to
transition metals have thus far been unsuccessful except in
rare cases where a bidentate structure was formed. Even with
*Corrresponding author. Fax: +1-20-8885-6198.
1Present address: Department of Chemistry, University of Rajasthan,
Jaipur, India.
0022-1139/98/$ ± see front matter # 1998 Elsevier Science S.A. All rights reserved.
P I I : S 0 0 2 2 - 1 1 3 9 ( 9 8 ) 0 0 2 6 8 - 1

148
O.D. Gupta et al. / Journal of Fluorine Chemistry 92 (1998) 147±151
transition metals, reactions of (cyclen)PH usually gave
pentacoordinate structures arising from the typical trigonal
bipyramidal (tbp) geometry associated with phosphorus(V)
[6±9,16,17]. Lattman et al. have reported the synthesis and
X-ray crystal structure of the ®rst monodentate P-bound
transition metal complex of 2A1 which revealed a P±N
transannular interaction ± a unique geometry for a phos-
phine ligand. This complex provided the ®rst structural
con®rmation of the tbp-constraining `bite' of the cyclen
ring at phosphorus [18]. Although a few metal derivatives of
2A were reported, the chemistry of cyclenphosphorane is
not well explored. To the best of our knowledge, there are no
literature reports that describe the chemistry of cyclenphos-
phorane with ¯uorine-containing compounds. In this paper,
we report the ®rst examples of derivatives of cyclenPH that
contain ¯uorine and/or ¯uorine and chlorine substituents.
We also report evidence for the open form of cyclenphos-
phorane (2A1) in the presence of organic compounds. In
our efforts to compare the reaction chemistry of 2Awith that
of cyclamphosphorane (2B), we were only able to isolate
products that were the result of reaction of the oxidized form
of the phosphine tautomer. Ligand substitution occurs at
nitrogen and not at phosphorus.
19F NMR spectra were obtained on a JEOL FX-90Q FT
NMR spectrometer with CFCl3 as internal reference. H
1
NMR spectra were run in 5 mm NMR tubes in CDCl3 and
the peak positions were measured relative to residual CHCl3
and reported relative to Me4Si. 31P NMR spectra were
obtained on this instrument at 36.2 MHz and phosphorus
spectra were calibrated using external 85% phosphoric acid
as the reference with an internal locking mode. Infrared
spectra were obtained on a Perkin-Elmer 1700 FT-IR spec-
trometer using KBr discs for involatile liquids and KBr
pellets for solids.
2.3. Method
A stoichiometric amount of the starting material (50 mg;
0.25 mmol) was dissolved in 10 ml of THF and was placed
in a 100 ml round-bottomed ¯ask equipped with a 10/14
ground glass standard taper joint and a stirring bar. A
stoichiometric amount of triethylamine was added to the
solution. An equivalent stoichiometric amount of haloalk-
enyl/halophenyl was weighed, dissolved in 2 ml of THF,
added to the ¯ask (for volatile materials vacuum line
transfer was used) and the components were well mixed.
The mixture was allowed to stir at 258C for 24 h. The solid
that separated was removed by ®ltration. The ®ltrate was
concentrated. The residue was taken up in THF and
10% benzene (by volume) was added. After ®ltration, the
®ltrate was concentrated and the pure compound was
obtained.
2. Experimental section
2.1. Materials
1,4,7,10-tetraazacyclododecane (cyclen) (1A), 1,4,8,11-
tetraazacyclotetradecane (cyclam) (1B), cyclenphosphorane
(2A), cyclamphosphorane (2B) and cyclamphosphine oxide
(2C) were prepared either by the method of Richman [1] or
obtained as a gift from Dr. J. E. Richman. 1,2-dichloro-
tetra¯uorocyclobutene-1 (3), 1,2-dichlorohexa¯uorocyclo-
pentene-1 (4), 1,2-dichloroocta¯uorocyclohexene-1 (5),
iodopenta¯uorobenzene (6), 2-iodo-1,1,1-tri¯uoroethane
(7) and 2,3-dichlorohexa¯uorobutene-2 (8) were obtained
from PCR Inc. and used as received. Triethylamine and THF
2.4. Synthesis
2.4.1. Cyclen(chlorotetrafluorocyclobutenyl)phosphorane
(A)
The triethylammonium salt was removed by extraction
with chloroform : hexane (30 : 70) solvent mixture to give a
thick oily yellow compound in 30% yield. Spectral data
1
obtained: 19F NMR: ꢀ ˆ 110.69 (2F), 113.77 (2F); H
Ê
were obtained from Aldrich and used after drying with 4 A
molecular sieve.
NMR: ꢀ ˆ 2.8±3.5 (m, 16H); 31P NMR: ꢀ ˆ 46.28. MS
‡
‡
(CI ): m/z ˆ 358 (M ). IR (KBr plates): 2942 (s), 2890 (s),
1684 (s) 1682 (ms), 1563 (w), 1545 (w), 1461 (s), 1362 (ms),
1290 (s), 1224 (s), 1080 (s) cm
1
2.2. General procedure
.
A conventional Pyrex glass vacuum system equipped
with a Heise±Bourdon tube gauge and a Televac thermo-
couple gauge was used to handle gases and volatile liquids.
Volatile compounds were measured quantitatively by using
PVT techniques. All reactions and manipulations were
carried out in an atmosphere of prepuri®ed dinitrogen or
under vacuum unless otherwise indicated. Solvents were
rigorously dried over appropriate drying agents and distilled
and deoxygenated prior to use. Mass spectra were recorded
with a VG -7070 HS mass spectrometer operating at 10 eV.
Correct chlorine isotopic ratios were observed in each case.
2.4.2. Cyclen(chlorotetrafluorocyclopentenyl)phosphorane
(B)
A thick oily compound was obtained in 90% yield.
Spectral data obtained: 19F NMR: ꢀ ˆ 108.10 (2F),
113.39 (2F), 130.63 (2F); 1H NMR: ꢀ ˆ 2.75 (m, 16H);
‡
‡
31P NMR: ꢀ ˆ 45.83. MS (CI ): m/z ˆ 408 (M ).
‡
HRMS(FAB ) Calcd. for C13H16N4PF6ÁHCl: 409.0785;
Found: 409.0785. IR (KBr plates): 2921 (s), 2851 (s),
1772 (ms), 1577 (bs), 1337 (s), 1276 (ms), 875 (s) 648
1
(ms) cm
.

O.D. Gupta et al. / Journal of Fluorine Chemistry 92 (1998) 147±151
149
2.4.3. Cyclen(chlorooctafluorocyclohexenyl)phosphorane
(C).
Spectral data obtained: 19F NMR: ꢀ ˆ 109.52 (2F),
1
111.76 (2F); H NMR: ꢀ ˆ 2.8±4.2 (bm, 16H), 1.9±2.2
‡
A liquid, yellow, thick, oily compound was obtained in
70% yield. Spectral data obtained: 19F NMR: ꢀ ˆ 106.21
(2F), 108.91 (2F), 133.42 (2F), 135.05 (2F); 1H NMR:
(bm, 4H); 31P NMR: ꢀ ˆ ‡28.04. MS (CI ): m/z ˆ 402
‡
‡
‡
(M ), 383 (M
2922 (s), 2853 (s), 1658 (s), 1462 (s), 1411 (w), 1264 (s),
F), 243 (M
C4F4Cl). IR (KBr plates):
‡
1
1180 (s), 978 (m), 866 (w), 687 (bm) cm .
ꢀ ˆ 2.7±3.0 (m, 16H); 31P NMR: ꢀ ˆ 47.71. MS (CI ):
‡
m/z ˆ 458 (M ). IR (KBr plates): 2937 (vs), 2873 (vs), 1655
(bm), 1544 (s), 1466 (m), 1388 (m), 1249 (s), 1226 (m),
1190 (m), 1146 (m), 1128 (m), 1086 (s), 870 (w), 672
2.4.8. N-(chlorohexafluorocyclopentenyl)cyclamphosphine
oxide (H)
1
(ms) cm
.
The reaction was performed on a 0.25 mmol scale. The
salt formed was separated, and the ®ltrate was concentrated
to give compound H as a thick oil in 60% yield. Spectral
data obtained: 19F NMR: ꢀ ˆ 108.50 (2F), 110.05 (2F),
2.4.4. Cyclen(pentafluorophenyl)phosphorane (D)
50 mg (0.25 mmol) cyclenphosphorane was taken in a
100 ml round bottomed Pyrex ¯ask equipped with a 14/20
ground glass standard joint and magnetic stirring bar and
dissolved in 2 ml dry chloroform. Iodopenta¯uorobenzene
(74 mg, 0.25 mmol) was added and the mixture was stirred
slowly for 12 h. A white solid was formed. It was separated
by ®ltration and washed with 10 ml dry chloroform and
dried under vacuum. D was obtained in 90% yield. Spectral
data obtained: 19F NMR: ꢀ ˆ 120.85 (ortho, 2F), 153.39
(p, 1F), 159.57 (m, 2F); 1H NMR: ꢀ ˆ 2.9±3.1 (m, 16H);
1
127.28 (2F); H NMR: ꢀ ˆ 1.65 (m, 4H), 2.6±3.2 (m,
‡
‡
16H); 31P NMR: ꢀ ˆ ‡30.98. MS (CI ): m/z ˆ 452 (M ),
‡
‡
‡
433 (M 2HF2), 243 (M
(KBr plates): 2959 (s), 2858 (s), 1630 (bs), 1587 (m), 1487
F), 413 (M
C5F6Cl). IR
(w), 1473 (m), 1457 (m), 1391 (w), 1261 (s), 1171 (vs), 982
1
(s), 731 (m) cm
.
2.4.9. N-(chlorooctafluorocyclohexenyl)cyclamphosphine
oxide (I)
‡
‡
31P NMR: ꢀ ˆ 42.28. MS (CI ): m/z ˆ 366 (M );
‡
HRMS(CI ) Calcd. for C14H16N4PF5: 366.1032; Found:
366.1040. IR (KBr plates): 3019 (m), 2947 (s), 2879 (vs),
Compound I was obtained in 50% yield as a thick oil.
Spectral data obtained: 19F NMR: ꢀ ˆ 106.02 (2F), 108.69
(2F), 133.22 (2F), 135.15 (2F); 1H NMR: ꢀ ˆ 1.63 (m, 4H),
1685 (s), 1511 (m), 1482 (m), 1456 (s), 1392 (s), 1237 (vs),
1
968 (ms), 849 (s), 710 (s) cm
.
‡
2.63- 3.18 (m, 16H); 31P NMR: ꢀ ˆ 31.50. MS (CI ):
‡
m/z ˆ 503 (M ‡ 1). IR (KBr plates): 2960 (s), 2848 (s),
2.4.5. Cyclen(trifluoroethyl)phosphorane (E)
1640 (m), 1472 (m), 1450 (m), 1385 (w), 1259 (s), 1184
.
1
The oily, yellowish liquid was obtained in 60% yield.
Spectral data obtained: 19F NMR: ꢀ ˆ 58.32 (3F); 1H
NMR: ꢀ ˆ 4.04 (q, 2H), ꢀ ˆ 2.8±3.2 (m, 16H); 31P
(vs), 975 (s), 725 (m) cm
‡
‡
NMR: ꢀ ˆ 42.54. MS (CI ): m/z ˆ 283 (M ‡ 1). IR
3. Results and discussion
(KBr plates): 2945 (s), 2911 (s), 1636 (w), 1588 (vs),
1490 (s), 1348 (m), 1300 (m), 1224 (s), 948 (m), 930
(m), 850 (bm), 730 (s), 672 (s) cm
The cyclicphosphoranes, 2A and 2B, were reacted via
three routes with a variety of cyclic and acyclic compounds
that contained labile halogen substitutents: (a) with the
lithiated derivatives of 2A and 2B in tetrahydrofuran
(THF) at re¯ux for 12 h; (b) with 2A and 2B in CHCl3 at
258C for 12±14 h; (c) with 2A and 2B in the presence of
triethylamine in THF at 258C for 12±24 h.
With lithiated phosphoranes, a variety of products were
formed in very low yields and puri®cation was dif®cult.
When the phosphoranes were reacted in CHCl3, the pro-
ducts were obtained in very good yields and their isolation
and puri®cation were straightforward. Because of the small
scale on which the reactions were carried out, it was not
possible to measure the quantity of HX obtained. However,
when an organic base was present, the trialkylammonium
salt that formed provided indirect evidence that the reaction
proceeded as desired. Tetrahydrofuran (THF) was the sol-
vent of choice for these reactions since the phosphorane
products were soluble while the salts that formed precipi-
tated in essentially quantitative amounts, indicating that the
reactions occurred as follows:
1
.
2.4.6. 2-Chlorohexafluorobut-2-enylcyclenphosphorane
(F)
The reaction was carried out on a 50 mg, (0.25 mmol)
scale, using the stoichiometric ratio 1 : 1 of the reactants.
The yellow, thick, oil was obtained in 20% yield. Spectral
data obtained: 19F NMR: ꢀ ˆ 61.53 (m, 3F), 59.24 (m,
3F); 1H NMR: ꢀ ˆ 2.8±3.2 (m, 16H). 31P NMR: ꢀ ˆ
‡
‡
45.83. MS (CI ); m/z ˆ 396 (M ). IR (KBr plates):
2937 (s), 2868 (vs), 1688 (m), 1664 (w), 1455 (ms),
1310 (s), 1244 (s), 1176 (vs), 1121 (vs), 1066 (m), 954
(ms), 910 (s), 765 (w), 721 (s), 644 (m) cm
1
.
2.4.7. N-(chlorotetrafluorocyclobutenyl)cyclamphosphine
oxide (G)
The reaction was carried out on a 0.25 mmol scale. The
salt that formed was separated, and the ®ltrate was con-
centrated to leave compound G as a thick oil in 70% yield.

150
O.D. Gupta et al. / Journal of Fluorine Chemistry 92 (1998) 147±151
3.1. Reactions with 2A
in essentially quantitative yields supporting the formation of
products B and C, respectively. However, when puri®cation
was attempted by using bulb-to-bulb distillation, decom-
position occurred to give the ¯uorocyclenphosphorane (J)
which was con®rmed by comparing the 31P and 19F NMR
spectra and mass spectroscopy (MS) with the previously
reported literature values [20]. Cyclohexene 5 with 2A in the
presence of triethylamine in THF gave J in 25% yield in
addition to product C.
As stated in the Section 1, 2A exists only as the `closed'
tautomer and does not show the `open' tautomer form either
in solution or in solid or gas phase. The ®rst monodentate P-
bound transition metal complex of 2A was prepared and its
X-ray crystal structure was obtained by Lattman [6±9]. In
our studies, cyclenphosphorane was reacted with chloro-
¯uoro or iodo¯uoro compounds to form products that con-
tained pentacoordinated phosphorus. Interestingly, when
dichlorotetra¯uorocyclobutene (3) was reacted with 2A in
the presence of (C2H5)3N, to give A, the reaction occurred
more rapidly than with the dichloroper¯uorocyclic ole®ns 4
and 5. The 31P NMR spectrum showed a signal at
ꢀ ˆ ‡110 ppm which is a marked shift from the region
characteristic for P(V) at ꢀ ˆ 46.28 ppm. This suggested
that a P(III) derivative may be present based on the follow-
ing equilibrium:
Although the reaction of 5 with cyclenphosphorane was
slower than with the four- and ®ve-membered cyclic ole®ns,
the reaction rate was much faster than with tetraazamacro-
cyclic amines where many days were required for the
reaction to reach completion even at higher temperature.
However, the reactions of 3 with the latter amines were also
much faster than the reactions of the amines with 4 and 5
[18±21].
In attempts to form the 2 : 1 products, the cyclic ole®ns 3,
4 and 5 were reacted with 2A in a 2 : 1 stoichiometric ratio
in the presence of triethylamine at 258C for 24 h and then at
ꢀ608C for 6 h. In all cases, only 1 : 1 products were formed
(A, B and C) and unreacted 2A was recovered.
All attempts to isolate the proposed P(III) derivative
failed.
In reactions of 2A with 4 and 5, similar shifts in the 31P
NMR signals were not observed. When 4 and 5 were reacted
with 2A in the presence of a base, the reaction rate was
slower than with 3. Similar reaction rates were also observed
in our earlier studies with tetraazamacrocyclic amines [19].
The amine salts were recovered from the reaction mixtures
Iodopenta¯uorobenzene (6) reacted smoothly with 2A in
the presence of triethylamine in THF at 258C to form D in
90% yield. Bromopenta¯uorobenzene also reacted under
similar conditions with 2A to give D in 70% yield. The
reaction rate was slower than with 5. When iodotri¯uoro-

O.D. Gupta et al. / Journal of Fluorine Chemistry 92 (1998) 147±151
151
ethane (7) was allowed to react with 2A under similar
conditions, the reaction took place slowly with a concomi-
tant color change from colorless to yellow. To compare with
the reactivity of cyclic alkenes towards 2A, CF3C(Cl)=
C(Cl)CF3 (8) was also reacted to form F. Substitution of
a single chlorine atom was observed but the yield was
somewhat lower than with the cyclic ole®ns.
are slightly soluble in THF and methylene chloride and
soluble in acetonitrile, dimethylformamide and dimethyl
sulfoxide.
The infrared spectra of all of the products reported in this
paper are consistent with their expected structures. Cyclic
alkenyl bonds are observed as strong bands between 1600
and 1750 cm 1. Ring protons of the substituted cyclenphos-
phorane or cyclamphosphorane are found at frequencies
between 2950 and 2990 cm 1. The double bonds between
phosphorus and oxygen are seen as medium to strong
3.2. Reactions with 2B
1
In contrast to 2A, cyclamphosphorane (2B) exists in
tautomeric forms suggesting that it might exhibit different
chemical behavior towards dichloroper¯uorocyclic and
acyclic alkenes. The reactions between 2B and dichloroper-
¯uorocyclic alkenes (3, 4 and 5) were carried out under the
same conditions used for the reactions with 2A. While
reactions occurred with 3, 4 and 5, the desired products
could not be isolated due to the complex product mixtures.
Apparently the P(III) tautomer was oxidized during the
reaction to form the phosphine oxide.
vibrations between 1400 and 1480 cm for G, H, and I.
Acknowledgements
We are grateful to the National Science Foundation
(Grant CHE-9003509) and to the Air Force Of®ce of
Scienti®c Research (Grant 91-0189) for support of this
research. We thank Dr. G.D. Knerr for mass spectra.
References
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The compounds G, H, and I have been isolated and char-
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spectra were obtained that showed peaks assignable to
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