Transformations of F-Alkyl Iodides and Bromides Induced by Nickel(0) Carbonyl

Article abstract of DOI:10.1021/jo970805y

Adducts of primary F-alkyl iodides with nickel carbonyl are formed readily in donor solvents and pyrolyze at 100-150 °C to give olefinic coupling products in high yield. The mechanism proposed to account for the observed chemistry involves preferential α-elimination of fluorine with formation of a carbenoid species complex coordinated to nickel. Differences in reaction paths among several types of substrate halides are rationalized on the basis of polarization of the Ni-C bond in the adducts. Support for these proposals is provided by state-of-the-art calculations.

Full text of DOI:10.1021/jo970805y

3
6
J . Org. Chem. 1998, 63, 36-43
Tr a n sfor m a tion s of F-Alk yl Iod id es a n d Br om id es In d u ced by
Nick el(0) Ca r bon yl†
Carl G. Krespan*
DuPont Central Research & Development, Experimental Station, P.O. Box 80328,
Wilmington, Delaware 19880-0328
David A. Dixon
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory,
P.O. Box 999 K1-83, Richland, Washington 99352
Received May 5, 1997X
Adducts of primary F-alkyl iodides with nickel carbonyl are formed readily in donor solvents and
pyrolyze at 100-150 °C to give olefinic coupling products in high yield. The mechanism proposed
to account for the observed chemistry involves preferential R-elimination of fluorine with formation
of a carbenoid species complex coordinated to nickel. Differences in reaction paths among several
types of substrate halides are rationalized on the basis of polarization of the Ni-C bond in the
adducts. Support for these proposals is provided by state-of-the-art calculations.
In tr od u ction
adopted as the synthetic approach. In contrast to the
previous studies, the goal was to carry through to
organofluorine products.
Our search for new synthetic methods in organofluo-
rine chemistry based on readily available zero-valent
metal carbonyls as reagents centered first on iron pen-
tacarbonyl.1 Depending upon reaction conditions, this
reagent was shown to convert primary F-alkyl iodides
into F-1-iodo-1-alkenes or into F-alkyl radicals capable
Resu lts a n d Discu ssion
Reaction is not observed between F-alkyl iodides and
Ni(CO) in neat mixtures but does occur readily in donor
4
2
of F-alkylating aromatic substrates. A later study of the
solvents at 25-60 °C. The usual mechanistic sequence
probably obtains, one in which reversible loss of CO gives
transformations of R-chloro fluoro ketones mediated by
nickel carbonyl has now been extended to other fluoro-
alkyl halides as substrates. Marked differences emerge
between the chemistries mediated by the iron vs the
nickel reagents.
A number of stable F-alkylnickel(II) compounds bear-
ing various ligands have appeared in the literature, so
stable that, as with the iron(II) derivatives, prospects for
catalytic reactions seem low.4 The reactions were there-
fore run with equimolar amounts of the metal carbonyl.
Oxidative addition of a variety of fluoroalkyl halides to
Ni(CO) having a vacant coordination site, coordination
3
of Ni(CO) at iodine, followed by single-electron transfer
3
to give a charged, solvated intermediate. Subsequent
transfer of iodide ion to the metal followed by radical
combination leads to product. Steady loss of CO occurs
during reaction, so that the final product contains two
molecules of the donor solvent, generally acetonitrile in
our reactions, and no carbon monoxide. Equation 1
illustrates the formation of F-hexylnickel derivative 1
starting from F-hexyl iodide.
3
nickel tetracarbonyl, corresponding to one of the known
general reactions producing L
2
NiXR
F
compounds,3 was
a
†
DuPont Publication no. 7529.
X
Abstract published in Advance ACS Abstracts, December 1, 1997.
1) Krespan, C. G. J . Fluorine Chem. 1988, 40, 129.
(
(
(
2) Krespan, C. G. J . Fluorine Chem. 1994, 66, 311.
3) (a) Oxidative substitution of various bis-ligand Ni(0) compounds
F 2 F
with R I are known to give isolable derivatives of the type L NiIR ;
see, for example, the following: McBride, D. W.; Stafford, S. L.; Stone,
F. G. A. J . Chem. Soc. 1963, 723. Ashley-Smith, J .; Green, M.; Stone,
F. G. A. J . Chem. Soc. A 1969, 3019. (b) Direct reaction of nickel metal
F-Octyl iodide also adds to nickel carbonyl in acetoni-
trile or, more slowly, in benzonitrile media to form
adducts 2.
(
deposited from the vapor phase) with trifluoromethyl radicals has been
used to prepare Ni(CF , isolated as the stable bis(trimethylphosphine)
3 2
)
derivative by Firsich, D. W.; Lagow, R. J . J . Chem. Soc., Chem.
Commun. 1981, 1283. (c) McBride et al. (McBride, D. W.; Dudeck, E.;
Stone, F. G. A. J . Chem. Soc. 1964, 1752) report the synthesis of the
type π-C
π-C Ni(CO)]
attach an R group to nickel; for example, Krause et al. (Krause, L. J .;
5
H
5
-Ni(CO)R
F
by oxidative cleavage of the Ni-Ni bond in
[
5
H
5
2
with R
F
I. (d) Exchange reactions can also be used to
F
Morrison, J . A. J . Chem. Soc., Chem. Commun. 1981, 1282) carried
out the following reactions:
Proceeding from primary F-alkyl iodide to bromide to
chloride, that is, in the direction of decreasing ease of
electron transfer, gives progressively lower reactivity
toward nickel carbonyl. Bromides, as exemplified by
(
CF ) Cd‚glyme + NiX ‚2PR f CF NiX‚2PR f (CF ) Ni‚2Pr
3 2 2 3 3 3 3 2 3
(4) (a) Hughes, R. Adv. Organomet. Chem. 1990, 31, 183. (b) See,
however: Yang, Z.-Y. J . Am. Chem. Soc. 1996, 118, 8140.
S0022-3263(97)00805-0 CCC: $15.00 © 1998 American Chemical Society
Published on Web 01/09/1998

Ni(0)CdP-Induced Transformations of F-Alkyl Halides
Sch em e 1
J . Org. Chem., Vol. 63, No. 1, 1998 37
F-octyl bromide, react much more slowly than iodides,
while chlorides are unreactive at moderate temperatures.
The product from a fluoroalkyl bromide gives chemistry
similar to that from an iodide, indicating that the
to Ni(II). Insertion of this very reactive carbenoid species
into a nearby C-Ni σ-bond5b proceeds cleanly to generate
6 containing a secondary perfluoroalkyl group bonded to
nickel. As the evidence indicates (vide infra), heterolysis
of this new C-Ni σ-bond leads to carbanion 7, from which
olefins 5 are formed by nonregioselective â-elimination
of fluoride. Since â-elimination can evidently occur in
two and only two directions with about equal ease to give
∆ and ∆ olefins, this mechanism leads to the product
mix actually obtained. The isomers 5 are clearly kinetic
products, since contact with an acetonitrile solution of
TASF at 25 °C or CsF/diglyme at 100 °C caused the
appearance of new olefin isomers in the mixture.
(fluoroalkyl)nickel moiety tends to thermolyze indepen-
dently of the halide ion present.
F-Alkylnickel(II) derivatives with appropriate ligands
3
are known to be stable, as are compounds such as 1 and
5
6
2
. These crude products could be stored for weeks under
nitrogen at 25 °C with little degradation.
An ester function is tolerated provided it is located
some distance from the iodo substituent, as shown in eq
3
.
The fluoroalkyl-nickel bond in compounds such as 1
is not only stable for prolonged periods at 25-50 °C but
also remains essentially intact at 80 °C for hours. This
level of stability was demonstrated when product 1,
prepared from 0.1 mol each of F(CF
refluxed with 100 mL of benzene for 12 h. The red solid,
2 6 4
) I and Ni(CO) , was
F-Allyl iodide is unusual in that it reacts exothermi-
cally to form the rearranged coupling products, known
diene isomers 4, directly. In this case, we propose that
the expected intermediate isomerizes to the F-propenyl
derivative, which then can heterolyze to give F-propenyl
anion capable of attack on F-allyl iodide to form diene.
The observed product, 4, is the result of equilibration of
the diene.
1
2
5
, which was still present after removal of volatiles at
5 °C under vacuum, was pyrolyzed to give 19 g (63%) of
. Minor amounts of F(CF
I were also formed, but no products from interac-
tion with the benzene ring were detected.
2 4 2 2 5
) CFdCF , F(CF ) H, and
2 6
F(CF )
An intramolecular version of the coupling reaction is
observed on pyrolysis of the intermediate from interaction
of F-1,6-diiodohexane with an excess of Ni(CO)4. F-
Cyclohexene is obtained in essentially one step from the
diiodide. Low molecular weight iodine-containing poly-
mer presumed to have the general structure 8 is also
formed.
Pyrolysis of F-alkylnickel halides such as 1 occurs at
temperatures above about 120 °C to give a mixture of
two olefinic coupling products in remarkably high yield.
Analyses by 19F NMR, IR, Raman, and GC/MS show an
approximately 1:1 mixture of trans-F-dodecene-6 (5a ) and
trans-F-dodecene-5 (5b). We interpret the facts that only
two closely related olefins are formed and those by a
highly efficient coupling reaction to mean that formation
of a carbenoid intermediate is a key step.5 As indicated
in Scheme 1, R-elimination of fluorine can provide a
perfluorohexylene species in the inner sphere coordinated
The carbomethoxy group survives the pyrolytic cou-
pling conditions well, as indicated by the results obtained
on pyrolysis of 3 to form 9a ,b.
a
(5) (a) See ref 4b for a discussion of difluorocarbene complexes with
nickel and for leading references. (b) A reviewer has pointed out that
although we have found no literature on disproportionations of
(
perfluroalkyl)nickel derivatives as is indicated in Scheme 1, Klabunde
et al. (Klabunde, K. J .; Anderson, B. B.; Bader, M.; Radomovitch, L. J .
J . Am. Chem. Soc. 1978, 100, 1313) established the formation of (C
Ni(PEt under some conditions from reactions known to produce
initially C NiBr.
6
5 2
F ) -
One feature of the proposed mechanism was tested by
reaction of nickel carbonyl with a secondary iodide, F-2-
3 2
)
6
F
5

3
8
J . Org. Chem., Vol. 63, No. 1, 1998
Krespan and Dixon
iodopropane, to attach nickel to a perfluoroalkyl group
at a secondary carbon. This intermediate, 11, could be
detected by 19F NMR but proved to be unstable at even
moderate temperatures. Decomposition occurred with
formation of F-propene, the expected product of â-fluoride
elimination, with no sign of coupling products.
Sch em e 2
An attempt to emulate the postulated insertion of a
carbenoid species into a Ni-C bond was made by addition
of ethyl diazoacetate as a carbene source to F-hexylnickel
iodide in acetonitrile at 25 °C. Rapid reaction occurred
with formation of mixed coupling product 12 in 7% yield.
The low yield of 12 may reflect the extent to which
carbethoxycarbene is generated with access to the inner
coordination sphere of nickel where the insertion could
proceed.
heterolysis of the primary adduct gives stabilized car-
banion 16 as precursor to olefin 17.
SET to a ClCF
CO) , since no reaction is observed with ClCF
the other hand, a Cl C- group does participate, as shown
by the reactivity of ClCF CF CCl toward Ni(CO) at 25
C. Several products are formed, and as indicated in
2
- or Cl
2
CF- group is disfavored with Ni-
(
4
2
CFCl . On
2
Com p u ta tion a l Resu lts
3
Our interpretation of the results hinges on the ease of
heterolysis of the C-Ni bond in the products of oxidative
F 2
addition, R NiX. Primary F-alkyl groups C and higher
form a stable, relatively covalent bond to nickel, so that
decomposition occurs by a synchronous transfer of R-flu-
orine from C to Ni and formation of coordinated carbene
via a three-center fluorine-bridged intermediate repre-
sented by 20.
2
2
3
4
°
Scheme 2, it is apparent that both R- and â-elimination
of halogen occur.
R-Elimination of chlorine is occurring at a much lower
temperature than it does with fluorine, in keeping with
the lower bond strength for C-Cl. Since the resulting
carbenoid species coordinated to nickel is formed while
carbon monoxide is still coordinated to nickel as well (as
indicated for 13), coupling of the two carbenes in the
nickel coordination sphere to form ketene 14 can occur.
The ketene is not isolated as such, since it rearranges to
the isomeric acid fluorides 15.6
The product from insertion of carbenoid ligand in 13
into a C-Ni bond also occurs to a minor extent. The
resulting (haloalkyl)nickel moiety can then ionize to give
a relatively stable carbanion that preferentially elimi-
nates a â-chlorine to afford olefin 18.7a
As the C-Ni bond becomes more polarized by the
presence of an R-fluoroalkyl group and the fluoroalkyl
group more effectively stabilizes a negative charge,
products of â-elimination tend to predominate. Similarly,
the anion-stabilizing influence of the trifluoroacetyl group
and of chlorine atoms as R-substituents serves to promote
heterolytic cleavage of the C-Ni bond followed by reac-
tions characteristic of the carbanions. This transition
from one mode of decomposition to another is detailed
in Figure 1.7b
To assess the relative stabilities of the carbanions, the
gas-phase acidities of various model species were calcu-
lated.8 The acidity gives information about the stability
of the anion relative to the strength of the C-H bond in
the neutral. The acidity of AH is defined as the value of
∆H(298) for reaction 9
The competing pathway for decomposition via â-elim-
ination of fluorine is also observed, no doubt because
(6) England et al. (England, D. C.; Solomon, L.; Krespan, C. G. J .
Fluorine Chem. 1973, 3, 63) report the same observation in the
synthesis of F-acryloyl fluoride with no indication of F-methylketene
in equilibrium.
(
7) (a) Krespan et al. (Krespan, C. G.; Harder, R. J .; Drysdale, J . J .
J . Am. Chem. Soc. 1961, 83, 3424) report the preparation of this olefin
by coupling of ClCF CF CCl with copper at elevated temperature (200
C). Synthesis of acetylene 19 by dechlorination of 18 is also reported.
b) Interestingly, Klabunde et al. (Klabunde, K. J .; Key, M. S.; Low, J .
2
2
3
°
(
F
Y. F. J . Am. Chem. Soc. 1972, 94, 1000) report results with R ZnI that
imply an ordering of reactivities similar to ours.
(8) Lias, S. G.; Bartmess, J . E.; Liebman, J . F.; Holmes, J . L.; Levein,
R. D.; Mallard, W. G. J . Phys. Chem. Ref. Data 1988, 17, Supplement
No. 1.
-
+
AH f A + H
(9)

Ni(0)CdP-Induced Transformations of F-Alkyl Halides
J . Org. Chem., Vol. 63, No. 1, 1998 39
Ta ble 1. Ga s-P h a se Acid ities (k ca l/m ol) of
F lu or oca r bon s
F igu r e 1. R-Elimination (type a) vs heterolysis (type b).
The acidity in kcal/mol can be calculated directly from
-
the total energies of AH and A , the difference in zero
point energies (a negative number) and a correction for
thermal effects and to convert from ∆E to ∆H as given
in eq 10.
∆
H (9) ) ∆E (elec) + ∆ZPE + 1.5
(10)
f
o
We show the directly calculated acidity results in Table
1
.
The direct calculation of gas-phase acidities can be
difficult to do accurately as an anion is produced and it
is more difficult to treat computationally the behavior of
negative ions because of the diffuse nature of the charge
distribution. Another means to calculate the acidity is
to calculate the heats of formation of the neutral and the
ion by some scheme and then to calculate ∆H(9) from
a
From experimental values.
the available ∆H
not known from experiment can be calculated from
isodesmic reactions if the heats of formation of three of
f
f
s. The ∆H s of the neutrals if they are
which yields BF- which has the same structure as A-.
The fluoride affinity is defined as -∆H for reaction 12.
the four species are known. The ∆H
are shown in Table 2 together with the isodesmic reac-
tions used to generate them. The ∆H s of the anions can
be calculated in two ways. The first is as a proton-
f
s for the neutrals
-
-
B + F f BF
(12)
f
We have previously been able to predict the relative
FAs of organofluorine compounds with good reliabil-
-
transfer reaction involving the CF
shown in reaction 11.
3
/CF
3
H couple as
ity.1
0,11
Furthermore, we have shown that we can
1
2
calculate absolute FAs with good reliability based on
the FAs of HF13 and CF
O
14
which have recently been
CF3- + AH f CF H + A-
2
(11)
3
reliably established. The fluoride affinity is calculated
as a relative value based on eq 13
This couple was chosen because the experimental heats
-
8
9
of formation of CF
3
and CF
3
H
are known although
-
-
-
CF O + B f CF O + BF
(13)
the heat of formation of CF
3
has somewhat larger error
3
2
bars ((10 kJ /mol ) (2.4 kcal/mol) than one would like.
The values of ∆H(11) are given in Table 3, and the
(
10) Dixon, D. A.; Fukunaga, T.; Smart, B. E. J . Am. Chem. Soc.
1986, 108, 4027.
11) Dixon, D. A.; Farnham, W. B.; Heilemann, W.; Mews, R.;
Noltemeyer, M. Heteroatom 1993, 4, 287.
12) Krespan, C. G.; Dixon, D. A. J . Fluorine Chem. 1996, 77, 117.
resulting ∆H
f
s are shown in Table 4. The second means
(
is to calculate the fluoride affinity (FA) of molecule B
(
(
9) Chase, M. W., J r.; Davies, C. A.; Downey, J . R., J r.; Frurip, D.
J .; McDonald, R. A.; Syverud, A. N. J ANAF Thermochemical Tables,
rd ed.; J . Phys. Chem. Ref. Data 1985, 14, Supplem 1.
(13) Wenthold, P. G.; Squires, R. R. J . Phys. Chem. 1995, 99, 2002.
(14) (a) Larson, J . W.; McMahon, T. B. J . Am. Chem. Soc. 1983,
105, 2944. (b) McMahon, T. B., private communication.
3

4
0
J . Org. Chem., Vol. 63, No. 1, 1998
Krespan and Dixon
Ta ble 3. P r oton Tr a n sfer Rea ction En er gies
Ta ble 2. Hea ts of F or m a tion (k ca l/m ol) of Neu tr a ls a n d
Ap p r op r ia te Isod esm ic Rea ction s
for the anions derived from perfluoroallyl anion. The
differences are larger for the other compounds, but the
agreement for the direct calculation of the acidity is
always better with the fluoride affinity values. However,
the acidity scale does not really depend on the type of
calculation except where HF lies on the scale as this is
an experimental value. The acidity trends in Table 1
show that the least stable acid is CF H followed by CF -
a
Experimental values. See refs 8 and 9.
and then corrected to an absolute value by adding the
above energy difference to the absolute value of FA(CF
49.9 kcal/mol. Given ∆H of B, one can then calculate
(BF ) from eq 12. The values of the absolute fluoride
affinities are given in Table 5, and the resulting ∆H
2
O)
)
∆
f
-
H
f
f
s
3
3
are shown in Table 4. Given the heats of formation of
the species in reaction 9 and that of the proton, the
acidities can also be calculated and these are given in
Table 1.
2 2 2
CF H and CF dCFCF H with the latter two compounds
having comparable acidities except on the fluoride affinity
scale. Note, however, that the latter acid would form
-
either CF dCFCF2 (no allylic delocalization) or the
2
The heats of formation of the anions from the two
methods do not agree with each other as well as one
would like. The values calculated from the proton
transfer reactions are uniformly more negative than
perfluorocyclopropyl anion. The next weakest acid is the
one derived from elongation of the alkane chain, CF CF -
3
2
CF H. Its isomer, CF CFHCF has a significantly higher
2
3
3
acidity (easier loss of a proton). The acid CF CCl H is a
3
2
those calculated from fluoride affinities. The best agree-
3 2
stronger acid than CF CF H by almost 20 kcal/mol,
-
ment is found for CF
similar to that of CF . The difference here is about 3
3
3
CF
2
which has the structure most
showing the significant stabilization by the Cl atoms R
to the carbanion center as compared to F atoms. The
strongest acid is that derived from the fluorocarbonyl
derivative. The ordering of the acidities correlates well
with the two pathways that are observed. The stronger
acids (more stable carbanions) give type b reactions which
are dominated by preliminary heterolysis. The weaker
acids favor the R-elimination type a pathways.
-
kcal/mol, and the difference approximately doubles for
-
-
CF
3
CF
2
CF
2
and (CF
3
)
2
CF . These differences are prob-
-
ably due to the fact that CF
3
is a small anion, and our
basis set does not describe it as well as the larger ones.
A larger difference of about 12 kcal/mol is predicted for
the anions derived from perfluoroallyl anion. This arises
from the basis size effect described above and to a
-
possible difficulty in describing the addition of F to
Con clu sion s
perfluoroallene or to an error in the predicted heat of
1
5
formation of CF
2
dCdCF
2
.
The pyrolytic behavior of primary (perfluoroalkyl)-
nickel(II) halides involves transfer of R-fluorine to nickel
followed by reactions of the carbenoid species so pro-
duced. The olefinic coupling products are formed in 56-
90% overall yield, providing a convenient one-pot route
The direct calculation of the acidity shows good agree-
ment with the acidities derived from fluoride affinities
(15) Dixon, D. A.; Smart, B. E. J . Phys. Chem. 1989, 93, 7772.

Ni(0)CdP-Induced Transformations of F-Alkyl Halides
J . Org. Chem., Vol. 63, No. 1, 1998 41
Ta ble 4. An ion Hea ts of F or m a tion (k ca l/m ol)
Ta ble 5. Absolu te F lu or id e Affin ities
stored over 4 Å molecular sieves) was stirred under N
2
at 50
°C for 6.5 h, at which point CO evolution had practically ceased
and appreciable crystalline red precipitate was present. The
dark red crystals, which readily turned green in moist air, were
filtered under nitrogen, rinsed with a little acetonitrile, and
dried under vacuum to afford 6.3 g of dark red crystals. IR
(
Nujol): 2310 and 2280 (complexed CN), traces only of CF
-
1
2
absorption near 1200 cm , and indications of H at 3330 and
-
1
1
1
630 cm
Anal. Calcd for C
4.88. Found: C, 12.82; H, 2.40; N, 6.93, Ni, 13.69.
The insoluble solid was impure NiI ‚2CH CN containing a
.
4
6 2 2
H I N Ni: C, 12.17; H, 1.53; N, 7.10; Ni,
a
b
2
3
∆
Hf from fluoride affinities (Table 5). ∆Hf from proton
c
very small amount of 1 and appeared to be slightly hydrated.
The dark red filtrate was evaporated to dryness at 0.2 mm
overnight to give 41.6 g of a red-black soft solid. IR (Nujol):
transfer reactions (Table 3). Experimental values from refs 8 and
9
.
-
1
2
340, 2310, 2290 (complexed CN), 1250-1100 cm (str, CF).
19
to such materials. Versatility of the synthesis is en-
hanced by tolerance of the presence of at least the ester
functionality.
NMR (CD
Ni), -113.9 (s, 2F, CF
3
CN): F φ -80.7 (s, 3F, CF
3
), -96.7 (s, 2F, CF
2
-
2
), -121.7 (s, 2F, CF
2
2
), -122.3 (s, 2F,
CF ), -125.87 (s, 2F, CF ). Weak bands for starting iodide
2
Introduction of groups at the R-position to provide
better stabilization of negative charge promotes forma-
tion of products of heterolysis of the C-Ni bond. Our
computational results support these conclusions in that
the ordering of anion stabilities correlates well with the
observed change in mechanism with fluoride ion standing
at the approximate dividing line between the two types
of pyrolytic cleavage.
were also present.
Anal. Calcd for C10
6 2
H F13IN Ni: C, 20.47; H, 1.03; F, 42.09;
N, 4.77; Ni, 10.01. Found: C, 20.52; H, 0.96; F, 43.99, 43.73;
N, 4.01, 3.98; Ni, 9.08, 9.06.
Well-defined crystals were not obtained, but the data
indicate the soluble product to be mainly structure 1.
(
b) A reaction similar to that above was carried out over 7
h. GC analysis indicated the presence of residual iodide, so
7.9 g (6.0 mL, 0.046 mol) of additional nickel carbonyl was
added, and the reaction was continued at 50 °C for 2 h. Only
a trace of iodide remained. Volatiles were removed from the
red suspension at 25 °C (0.2 mm) to give a dark red residue
which was pyrolyzed at 100-170 °C (1-0.1 mm). The pyroly-
sate collected in a -80 °C trap consisted of an upper layer of
acetonitrile and 28.6 g of a lower layer composed of 95% 5a +
Exp er im en ta l Deta ils
Boiling points are uncorrected. Unless otherwise specified,
1
9
F NMR spectra were taken at 188.2 MHz on 20% solutions
1
in CDCl
spectra were taken at 300.2 MHz on similar solutions with
Si(CH as internal standard.
CAUTION! Care must be exercised when using Ni(CO)
volatile, highly toxic material. All runs with it were carried
out under nitrogen in systems vented through a -80 °C cold
trap. Equipment and cold trap contents were decontaminated
3 3
with CFCl as internal standard, and H NMR
3
)
4
5b with traces of F(CF
2 4 2 2 6
) CFdCF , F(CF ) I, and other impuri-
4
, a
ties. The yield of isomers 5 is therefore 27.2 g (90%).
Pure 5 was isolated by fractionation as an approximately
1:1 mixture of trans olefins 5a and 5b, bp 74-75 °C (20 mm).
GC (fluorosilicone packed column): single component. Capil-
lary GC (methylsilicone column): 60/40 mixture of two com-
by treatment with Br
the hood.
2
or aqueous NaOCl before removal from
-1
puter-resolved components. IR (neat): 1250-1150 cm (CF).
-
1
1
F or m a tion a n d P yr olysis of F-Hexyln ick el Iod id e Bis-
a cet on it r ile) Com p lex (1) t o F-Dod ecen es 5a ,b . (a ) A
Raman: 1724.3 cm (trans-R
none; 19F (94.1 MHz) φ -81.6 (t of t, J FF ) 9.8, 2.5 Hz, 6F from
5a and 3F from 5b, CF ), -81.8 (t of t, J FF ) 10, 2.2 Hz, 3F
from 5b, CF ), -118.6 (m, 8F, CF Cd), -122.4 (m, 2F from
5b CF ), -123.3 (m, 4F from 5a and 2F from 5b, CF ), -124.1
F F 3
CFdCFR ). NMR (CFCl ): H
(
mixture of 44.6 g (0.10 mol) of F-hexyl iodide, 17.1 g (13 mL,
.10 mol) of nickel carbonyl, and 100 mL of acetonitrile
purified by distillation from P , degassed with N , and
3
0
(
3
2
2
O
5
2
2
2

4
2
J . Org. Chem., Vol. 63, No. 1, 1998
Krespan and Dixon
+
(
m, 4F from 5a and 2F from 4b, CF
CF ), -126.7 (m, 8F, CF
), -154.0 (m, 4F, dCF). A 19F NMR
spectrum taken at 376.5 MHz (CFCl ) clearly showed a 53/47
mixture of 5a and 5b. For 5a : F φ -81.6 (t of t, J FF ) 10.0,
.5 Hz, 6F, CF ), -118.7 (m, 4F, CF Cd), -123.5 (m, 4F, CF ),
124.4 (s, 4F, CF ), -126.8 (m, 4F, CF ), -154.0 (m, 2F, dCF).
For 5b, with some of the resonances still coincidental with
those of 5a : -81.6 (t of t, J FF ) 10.0, 2.5 Hz, 3F, CF ), -81.7
t of t, J FF ) 9.9, 2.2 Hz, 3F, CF ), -118.7 (m, 2F, CF C)),
118.9 (m, 2F, CF C)), -122.7 (m, 2F, CF ), -123.3 (m, 2F,
CF ), -124.1 (m, 2F, CF ), -125.1 (m, 2F, CF ), -126.8 (m,
F, CF ), -126.9 (s, 2F, CF ), -154.0 (m, 2F, -CF).
Anal. Calcd for C12 24: C, 24.02. Found: 24.23.
F or m a tion a n d P yr olysis of Ad d u ct 2. Addition of 27.2
2
), -125.0 (m, 2F from 5b,
51 (CHF
2
+), 50 (CF
2
+), 44 (CO
2
). Isomers of 10b were present
+
2
2
as very minor components. For cis-10b, GC/MS: m/e 258 (M ),
+
+
+
3
239 (M - F), 189 (M - CF
3
), 159 (CF
3
CFdCFCO , 100%
1
9
+
+
+
+
peak), 131 (C
3
F
5
), 112 (C
3
F
4
), 93 (C
3
F
3
), 83 (CF
3
CH
2
), 69
+
+
+
2
-
3
2
2
(CF
3
), 64 (CF
2
dCH
2
); essentially no M - CO (230) peak.
+
+
+
2
2
For trans-10b, GC/MS: m/e 258 (M ), 239 (M - F), 189 (M
+
+
- CF
3
+
), 159 (CF
), 93 (C
3
CFdCFCO , 100% peak), 131 (C
3
F
5
), 112
+
+
+
3
3
(C
3
F
4
3
F
3
), 83 (CF
3
CH
2
), 69 (CF
).
(
-
3
2
Distillate collected during the pyrolysis was 24.5 g of nearly
pure 9a ,b. GC/MS: m/e 516 (M ), 497 (M - F), 389 (M
+
+
+
2
2
-
+
+
2
2
2
CF
CH
CF
3
CH
CCF
CH C - CF
), 162 (CF dCFCFdCF
2
O
2
C), 361 (M - CF
2
3
CH
CH
CO), 212 (C
2
O
2
3
C - CO), 339 (M - CF -
+
+
2
2
2
2
O
2
), 311 (M - CF
3
2
O
2
2
C - CF CO), 261 (M -
+
+
F
3
2
O
2
2
CF
2
5
F
8
), 193 (C
5
F
7
), 181
), 143
+
+
+
(C
(C
4
F
F
7
5
2
2
), 149 (CF
), 127 (CF CH
), 83 (CF
3
CH
2
OCF
2
+
+
+
+
g (0.050 mol) of F-n-octyl iodide to 8.55 g (6.5 mL, 0.05 mol) of
nickel carbonyl gave a homogeneous mixture but no detectable
reaction. Reaction commenced with the addition of 21 mL of
benzonitrile; the mixture was stirred at 25 °C for 6 days while
slow evolution of gas (CO) and eventual precipitation of a red
4
), 131 (CF
2
dCFCF
), 100 (C
2
3
2
O
2
C ), 124 (C
4
F
4
),
),
+
+
+
+
+
112 (C
64 (CF
3
F
4
2
F
4
), 93 (C
3
F
3
3
CH
2
), 69 (CF
3
+
+
2
dCH
2
), 63 (C
2
F
2
H ). A mass spectrum taken late in
the peak had a negligible 339 peak for CF
so was presumed to be mainly 9b.
+
3
CH
2
O
2
CCF
2
and
solid occurred. The solution was purged with dry N
filtered under N
ether, dried in a stream of N
2
and then
Fractionation of the distillate afforded 21.2 g (61%) of mixed
2
. The red solid (about 4 g) was rinsed with
isomers 9a ,b, bp 50-51 °C (0.2 mm). IR (neat): 2990 (satd
1
-1
2
, and dissolved in CD
3
CN.
H
CH), 1800 (CdO), 1300-1100 cm (CF, C-O), with a weak
NMR showed a nine-line pattern for C
6
H
5
CN, but 19F NMR
band at 1720 (CdC). The NMR spectrum indicated a 2:5
1
showed no F, indicating the solid to be NiI
benzonitrile.
2
with complexed
mixture of a /b. For 9a , NMR (CDCl
3
): H δ 4.61 (q, J HF ) 7.5
1
9
Hz, CH
(m, 4F, CF
9b, NMR (CDCl
4.57 (q, J HF ) 7.5 Hz, 2H, CH
Hz, 3F, CH CF ), -74.7 (t, J HF ) 7.5 Hz, 3F, CH
(d of d of t, J FF ) 17, 12.5, 1.5 Hz, 2F, CdCCF CdO), -118.6
(m, 2F, CF CdC), -119.1 (t, J FF ) 10 Hz, 2F, CF CdO),
-125.1 (s, 2F, CF ), -155.8 (A branch d of m, J FF ) 139 Hz,
1F, dCF), -158.0 (B branch d of m, J FF ) 139 Hz, 1F, dCF).
Anal. Calcd for C12 : C, 27.93; H, 0.78; F, 58.89.
2
CF
3
); F φ -74.6 (t, J HF ) 7.5 Hz, 6F, CH
), -120.3 (m, 4F, CF ), -154.7 (m, 2F, dCF). For
): H δ 4.61 (q, J HF ) 7.5 Hz, 2H, CH CF ),
CF
); 19F φ -74.6 (t, J HF ) 7.5
CF ), -110.2
2 3
CF ), -119.1
Distillation of the filtrate gave 13.0 g (48%) of recovered
F(CF I, bp 30-35 °C (2 mm), followed by benzonitrile, and
2
2
1
2
)
8
3
2
3
then 3.6 g of crystalline product which collected in the stillhead
as the pot temperature rose to 190 °C. Sublimation of the solid
at 35 °C (0.2 mm) afforded 2.8 g (14% conv) of product
2
3
2
3
2
3
2
-1
fluoroolefins, mp 36-38 °C. IR (melt): 1300-1100 cm (CF).
2
2
-
1
19
Raman: 1729.7 cm (sym CdC). F NMR at 94.1 MHz did
not distinguish between the two olefins believed to be present,
although broadening of some peaks was noted. NMR
2
4 16 4
H F O
1
19
(
-
CF
CFCl
3
): H none; F -81.7 (t of t, J FF ) 9.9, 2.3 Hz, 6F, CF
118.5 (m, 4F, CF Cd), -122.1 (m, 8F, CF ), -123.0 (m, 4F,
), -123.7 (m, 4F, CF ), -126.5 (m, 4F, CF ), -153.9 (m,
3
),
Found: C, 27.71; H, 0.82; F, 58.65.
F-Cycloh exen e fr om F-1,6-Diiod oh exa n e. A mixture of
55.4 g (0.10 mol) of F-1,6-diiodohexane, 100 mL of acetonitrile,
2
2
2
2
2
2
F, dCF).
Ad d ition of F-Octyl Br om id e to Ni(CO)
mixture of 25.0 g (0.05 mol) of F-n-octyl bromide, 50 mL of
acetonitrile, and 11.8 g (9.0 mL, 0.07 mol) of Ni(CO) was
and 17.1 g (13.0 mL, 0.10 mol) of Ni(CO)
days at 25 °C. Another 17.1 g (0.10 mol) of Ni(CO)
and the mixture was stirred for 2 days more. Then 8.55 g (0.05
mol) of Ni(CO) was added and the reaction continued for 3
days. The total of 10.5 mL of Ni(CO) which had collected in
the -80 °C trap was returned to the pot, and the reaction was
continued for another 11 days. Unreacted Ni(CO) and some
4
was stirred for 2
4
. A two-phase
4
was added,
4
4
stirred at 25 °C for 20 days while CO was very slowly evolved,
the lower phase was diminished, and a light-colored solid
eventually precipitated. Volatiles removed at 60 mm were
discarded; volatiles removed at 25 °C (0.1 mm) were found to
be acetonitrile and 8.0 g (32%) of recovered bromide as
separate layers. The pale green, moist, solid residue was
heated at 100-200 °C (0.1-0.5 mm) while product olefin (4.5
g, 23%) distilled and solidified. A sample of the crystallized
4
4
acetonitrile were removed by evacuation to 25 °C (20 mm);
then the remaining volatiles were transferred at 25 °C (0.1
mm) to give a moist, red solid residue. Pyrolysis was con-
ducted at 130-150 °C under vacuum over 3 h. Heating the
residue slowly to 205 °C (0.1 mm) allowed distillation of 6.0 g
of a viscous oil (8) with a broad boiling point range and from
which free iodine was being liberated at the higher tempera-
2 8
distillate, mp 40-42 °C, gave with olefin derived from F(CF ) I
a mixed mp 37-38.5 °C. GC showed the same single peak for
both samples.
-
1
tures. IR (neat): 1300-1100 cm (st, CF) with very weak
-
1
P r ep a r a tion of 2,2,2-Tr iflu or oeth yl 4-Iod oh exa flu o-
bands for unsaturation at 1785 and 1715 cm . Extraction of
the distillation residue with 100 mL of CFCl CF Cl and
evaporation of solvent gave 4.5 g of higher molecular weight
r obu tyr a te a n d Rea ction w ith Ni(CO)
4
. (a ) A mixture of
2
2
6
3.8 g (0.20 mol) of ICF CF CF COF, 22.0 g (0.22 mol) of 2,2,2-
2
2
2
-
1
trifluoroethanol, 17.0 g (0.40 mol) of NaF, and 50 mL of ether
was stirred overnight, filtered, and distilled to give 54.7 g (68%)
of 2,2,2-trifluoroethyl 4-iodohexafluorobutyrate, bp 64-66 °C
8 as a thick oil. IR (neat): 1300-1100 cm (st, CF) with a
1
-
weak band at 1715 cm (CdC). Attempted distillation of this
material caused further liberation of free iodine. The residue
was finally warmed with 3 × 500 mL of water to leave 8.3 g of
rubbery dark tar which exhibited a similar IR spectrum and
also liberated iodine on heating.
(
25 mm). IR (neat): 2980 (satd CH), 1800 (CdO), 1250-1100
-
1
1
cm (CF). NMR (CDCl
3
): H δ 4.59 (J HF ) 8 Hz, CH
I), -74.5 (t, J HF ) 8 Hz, 3F, CH
), -117.7 (t, J FF ) 11.5 Hz, 2F, CF
b) A mixture of 54.0 g (0.134 mol) of the ester, 150 mL of
purified acetonitrile, and 26.2 g (20.0 mL, 0.15 mol) of nickel
carbonyl was stirred under N at 50 °C for 7 h. GC indicated
2
CF
3
);
1
9
F φ -59.9 (m, 2F, CF
2
2
CF
3
),
-
114.8 (s, 2F, CF
2
2
).
Volatile products collected in cold traps during the pyrolysis
were washed with water, dried over CaSO , and distilled to
4
(
afford 8.3 g (32%) of F-cyclohexene, bp 50-52 °C, identified
by comparison of GC and IR traces with those of an authentic
sample.
F-Hexa d ien e-2,4 fr om F-Allyl Iod id e. A mixture of 78.3
g (0.30 mol) of F-allyl iodide and 100 mL of acetonitrile was
2
a trace only of unreacted ester. Volatiles were removed from
the mixture under vacuum to leave a dark red solid, assumed
to be mainly 3. This residue was heated at 100-170 °C (1-
0
.1 mm) over a 4-h period. Volatiles collected in a -80 °C trap
were mainly acetonitrile and 2.0 g (6%) of combined olefins
0a ,b, along with lesser amounts of recovered iodo ester and
4
stirred while 56.3 g (0.33 mol) of Ni(CO) was added dropwise
over an 8-h period. Rapid evolution of CO occurred during
the addition while the solution first decolorized (scavenging
of free iodine), then became dark red, and finally produced a
red crystalline precipitate. After having been stirred over-
night, the mixture was evacuated at 20 °C (40 mm) until 68
mL had collected in the -80 °C trap. Treatment of the trap
1
+
coupling products 9a ,b. For 10a , GC/MS: m/e 258 (M ), 239
+
+
+
(
(
(
M
2 2
- F), 230 (M - CO), 159 (CF dCFCF CO , weak), 131
+
+
+
+
3
CF
CF
2
3
dCFCF
2
), 127 (CF
3
CH
+
2 2 2 2 2
), 64 (CF dCH ), 63 (C F H ), 62 (C F ),
2 2 3 4 3
O C ), 112 (C F ), 93 (C F ), 83
CH
2
+), 69 (CF
3
+
+
+
2

Ni(0)CdP-Induced Transformations of F-Alkyl Halides
J . Org. Chem., Vol. 63, No. 1, 1998 43
contents with 65.8 g (0.26 mol) of I
until Ni(CO) was removed and transfer of volatiles at 20 °C
40 mm) gave 21.9 g (56%) of a lower layer of 4; GC indicated
a 34:51:15 ratio of cis,cis to cis,trans to trans,trans isomers.
Distillation afforded 19.2 g (49%) of fractions rich in each
isomer with a range of bp 39-58 °C. For the fraction bp 39-
2
in 200 mL of acetonitrile
tion of solid occurred while the mixture was stirred for 2 days.
Volatiles were transferred under vacuum and fractionated to
give a series of cuts, bp 67-81 °C. GC and NMR indicated
low yields of coupling products 18 and 19 present in the
highest and lowest boiling fractions, respectively.
4
(
In a fraction, bp 70-72 °C, the major components were 17
-
1
4
1
0 °C and 85:15 of cis,cis to cis,trans, IR (CCl
4
): 1750 (w) and
and Z-15. For 17, IR (CCl
4
): 1650 cm
(CdC). NMR
-1
1
19
710 (m) (conj. CdC), 1250-1150 cm (CF). The cis,cis isomer
(CDCl
2F, dCCF
198 + 200 + 202 (M ), 163 + 165 + 167 (M - Cl), 109 + 111
3
): H CH
3
CN singlet only; F φ -54.9 (d, J FF ) 12 Hz,
1
9
had NMR (CCl
4
): F φ 69.9 (d of t, J FF ) 10.8, 5.3 Hz, 6F,
2
Cl), -113.5 (t, J FF ) 12 Hz, 1F, dCF). GC/MS: m/e
+
+
CF
3
), -127.1 (s, J FF ) 5.3 Hz, 2F, central dCF), -139.4 (q,
FF ) 10.8 Hz, 2F, CF CF). For the fraction bp 50-56 °C and
9% cis,trans, IR (CCl ): 1740 (w) and 1705 (w) (conj. CdC),
300-1150 cm (CF). The cis,trans isomer had NMR (CCl ):
), -70.7
), -135.3 (d of m, J FF ) 38 Hz, 1F, dCF), -140.8
m, 1F, dCF), -148.0 (A branch d of d of q of m, J FF ) 144,
8, 21 Hz, 1F, transdCF), -154.0 (B branch d of m, J FF ) 144
Hz, 1F, transdCF). For the fraction bp 56-58 °C and 17:83
cis,trans to trans,trans; IR (CCl ): 1770 and 1705 (both
extremely weak, conj. CdC), 1300-1100 cm (CF). UV: λ225
nm CH CN 15 800. The trans,trans isomer had NMR (CCl ):
F φ -69.2 (m, 6F, CF ), -153.5 (A branch d of m, J FF ) 129
+
+
+
+
J
3
(C
3
F
2
Cl ), 93 (C
): 1840 (conj. COF), 1650 cm (CdC). NMR
): F φ 40.1 (d of t, J FF 17, 12 Hz, 1F, COF), -57.4 (t,
FF ) 12 Hz, 2F, dCCF Cl), -99.3 (d of t, J FF ) 17, 12 Hz, 1F,
dCF). GC/MS: m/e 210 + 212 + 214 (M ), 175 + 177 (M -
3
F
3
), 85 + 87 (ClCF
2
), 78 + 80 (C
2
FCl ). For
-
1
8
1
4
Z-15, IR (CCl
(CDCl
3
4
-
1
19
4
1
9
F φ -69.6 (d of d of d, J FF ) 21, 9.5, 3 Hz, 3F, CF
3
J
2
+
+
(m, 3F, CF
(
3
+
+
Cl), 163 + 165 + 167 (M - COF), 147 + 149 (M - Cl - CO),
+
+
+
3
3
125 + 127 (M - CF
2
3 2 3
Cl), 109 + 111 (C F Cl ), 93 (C F ), 85
+
+ 87 (ClCF
2
).
4
In a fraction, bp 81 °C, only acetonitrile and E-15 were
present. For E-15, IR (CH CN): 1830 (conj. COF), 1640
(CdC). NMR (CDCl /CH CN): F φ 31.3 (d, J FF ) 65.5 Hz,
1F, COF), -58.4 (d. J FF ) 8 Hz, 2F, dCCF Cl), -98.1 (d of t,
FF ) 65.5, 8 Hz, 1F, dCF). GC/MS: spectrum contains the
-
1
3
1
9
3
4
3
3
1
9
3
2
Hz, 2F, transdCF), -157.0 (B branch d of m, J FF ) 129 Hz,
2
J
F, transdCF).
same masses as for Z-26, but in slightly different proportions.
Yields based on GC analyses were 2.4 g (12%) of 17 and 4.2
g (20%) of mixed E/Z-15.
4
The reaction of F-allyl iodide with Ni(CO) gives close to
the thermodynamic mixture of diene isomers. When a 39:43:
+
1
1
3
2
8 mixture of isomers of 4 was heated with CsF catalyst at
00 °C for 6 h, the product was the same three isomers in a
3:44:20 ratio (GC result). Treatment with CsF at 150 °C for
0 h gave a 36:43:19 mixture. The presence of a short
For 18 (ref 7), GC/MS: m/e 364 + 366 + 368 (M ), 329 +
+
+
331 + 333 (M - Cl), 279 + 281 + 283 (M - CF
2
+
Cl), 229 +
+
231 + 233 (M - CF
2
CF
2
3 2
Cl), 109 + 111 (C F Cl ), 85 + 87
+
(ClCF
2
).
retention time peak in 1-2% amounts may be due to the
formation of a small amount of a F-hexyne; in contrast,
F-butadiene is isomerized readily to hexafluoro-2-butyne, since
two relatively high energy terminal double bonds are lost in
the process.
Com p u ta tion a l Deta ils
Geometries were gradient optimized16 with a double-ú basis
1
7
set augmented by polarization functions on C. This basis
set has been shown to give good results for the structures of a
1
8
wide range of fluorocarbons. Frequencies were calculated
analytically 19 at this level and scaled by 0.9 for use in
calculating the zero-point corrections to the reaction energies.
F or m a tion a n d Th er m olysis of Ad d u ct 11. Postulated
intermediate 6 is assumed to pyrolyze cleanly to olefin mixture
5
a ,b. On that basis, a secondary (fluoroalkyl)nickel derivative
Final energies were obtained at the MP2/DZP//HF/DZ+D
C
such as 11 would also be expected to form uncoupled olefin. A
mixture of 29.6 g (0.10 mol) of F-isopropyl iodide, 20 g (16 mL,
2
0
level. All calculations were done with the programs GRAD-
SCF21 on Cray computer systems and with Gaussian94 on
Silicon Graphics computer systems.
22
0
.12 mol) of nickel carbonyl, and 100 mL of acetonitrile was
stirred at 40 °C for 6.5 h. GC analysis indicated the iodide
was all reacted. Volatiles (15 mL) were partially removed at
Ack n ow led gm en t. The computational work was
performed under the auspices of the Office of Basic
Energy Sciences, U.S. Department of Energy, under
Contract DE-AC06-76RLO 1830 (Environmental Tech-
nology Partnerships Program) with Battelle Memorial
Institute, which operates the Pacific Northwest
Laboratory.
2
5 mm, and the residual red solution was indicated by NMR
to contain (CF
CFNiI. NMR (CD CN/CH
CN): 19F φ -67.5
broad s, 6F, CF ), -75.4 (broad s, 1F, CF-Ni), with only traces
3
)
3
2
3
3
(
of fluorinated impurities.
The remainder of the volatiles was removed under vacuum,
and the residue was pyrolyzed at 80-160 °C (0.5 mm).
Volatile products were identified by IR as hexafluoropropene
with a very minor amount of 2-H-heptafluoropropane; liquid
product was acetonitrile containing a trace of heptafluoroiso-
propyl iodide. No coupling product was detected.
J O970805Y
(16) (a) Komornicki, A.; Ishida, K.; Morokuma, K.; Ditchfield, R.;
Conrad, M. Chem. Phys. Lett. 1977 45, 595. (b) McIver, J . W., J r.;
Komornicki, A. Chem. Phys. Lett. 1971, 10, 202. (c) Pulay, P. In
Applications of Electronic Structure Theory; Schaefer, H. F., III, Ed.;
Plenum Press: New York, 1977; p 153.
Rea ction of Ad d u ct 1 w ith Eth yl Dia zoa ceta te.
mixture of 22.3 g (0.05 mol) of F(CF I, 100 mL of purified
acetonitrile, and 10 mL (13.1 g, 0.077 mol) of nickel carbonyl
was stirred under N at 50 °C for 6 h. The mixture was stirred
A
2 6
)
2
(17) Dunning, T. H., J r.; Hay, P. J . In Methods of Electronic
for 10 days while red crystals precipitated; GC indicated only
traces of starting materials left. When 5.7 g (0.05 mol) of ethyl
diazoacetate was added, immediate gas evolution and an
exotherm with dissolution of red solid occurred. Volatiles
removed under vacuum at 25 °C were almost entirely aceto-
nitrile. Pyrolysis of the residue at 100-180 °C (0.3 mm) gave
two main products along with additional acetonitrile. The first
was 10.6 g (71%) of isomeric F-dodecenes and 1.4 g (7%) of
ester 12, as indicated by the mass spectrum. GC/MS: m/e 359
Structure Theory; Schaefer, H. F., III, Ed.; Plenum Press: New York,
1977; Chapter 1.
(18) Dixon, D. A. J . Phys. Chem. 1988, 92, 86.
(
19) (a) King, H. F.; Komornicki, A. J . Chem. Phys. 1986, 84, 5465.
(
b) King, H. F.; Komornicki, A. In Geometrical Derivatives of Energy
Surfaces and Molecular Properties; J orgenson, P., Simons, J ., Eds.;
NATO ASI Series C., Vol. 166, D. Reidel: Dordrecht, 1986; p 207.
(20) (a) Moller, C.; Plesset, M. S. Phys. Rev. 1934, 46, 618. (b) Pople,
J . A.; Binkley, J . S.; Seeger, R. Int. J . Quantum Chem. Symp. 1976,
1
0, 1.
(21) GRADSCF is an ab initio program system designed and written
by A. Komornicki at Polyatomics Research.
22) Gaussian94, Frisch, M. J .; Trucks, G. W.; Schlegel, H. B.; Gill,
+
+
+
(
CF
M
- C
2
H
3
), 342 (M - C
2
H
4
O), 341 (M - C
2
2
H
5
+
O), 172 (CF
2
-
-
+
2
CFdCHCdO ), 153 (CF
dCFCFdCHCdO ), 122 (CF
2
(
+
+
+
3
CFdCHCdO ), 119 (CF3CF
2
), 117 (CFdCHCO
2
CH
2
CH
), 94
P. M. W.; J ohnson, B. G.; Robb, M. A.; Cheeseman, J . R.; Keith, T. A.;
Petersson, G. A.; Montgomery, J . A.; Raghavachari, K.; Al-Laham, M.
A.; Zakrzewski, V. G.; Ortiz, J . V.; Foresman, J . B.; Cioslowski, J .;
Stefanov, B. B.; Nanayakkara, A.; Challacombe, M.; Peng, C. Y.; Ayala,
P. Y.; Chen, W.; Wong, M. W.; Andres, J . L.; Replogle, E. S.; Gomperts,
R.; Martin, R. L., Fox, D. J .; Binkley, J . S.; Defrees, D. J .; Baker, J .;
Stewart, J . J . P.; Head-Gordon, M.; Gonzalez, C.; and Pople, J . A.,
Gaussian, Inc., Pittsburgh, PA, 1995.
+
+
+
(
CF
Ad d ition of 1,1,1,3-Tetr a ch lor otetr a flu or op r op a n e to
Ni(CO) . A mixture of 25.4 g (0.10 mol) of 1,1,1,3-tetrachlo-
rotetrafluoropropane and 50 mL of acetonitrile was stirred
under N at 25 °C while 17.1 g (13 mL, 0.10 mol) of nickel
carbonyl was added dropwise. Evolution of gas and precipita-
2 3 2 3
CFdCH ), 75 (C F H ), 69 (CF ).
4
2