Toward metal-mediated C-F bond formation. Synthesis and reactivity of the 16-electron fluoro complex [RuF(dppp)2]PF6 (dppp = 1,3-bis(diphenylphosphino)propane)

Article abstract of DOI:10.1021/om0000156

The five-coordinate fluoro complex [RuF(dppp)₂]PF₆ (1a) has been prepared by reacting [RuCl(dppp)₂]PF₆ (1b) with TlF (dppp = 1,3-bis(diphenylphosphino)propane). An X-ray investigation of 1a shows a distorted trigonal bipyramidal geometry (Y-shaped). The 16-electron complex 1a reacts with a number of donors, including CO, H₂, and F^-. The X-ray structure of trans-[RuF(CO)(dppp)₂]PF₆ (2aBPh₄) suggests that the π-donor ability of the fluoro ligand is only slightly higher than that of chloride. The reaction of 1a with [Me₄N]F gives cis-[RuF₂(dppp)₂] (3), a rare difluoro complex not stabilized by π-acidic co-ligands. The Ru-F bond of 1a is hydrogenolyzed upon reaction with H₂ to give [RuH(η²-H₂)(dppp)₂]⁺. The coordinatively unsaturated complex 1a reacts with activated haloalkanes R-X (X = Cl or Br) in 1:1 molar ratio to give the fluorinated organic derivative and [RuX(dppp)₂]⁺. The halide metathesis proceeds instantaneously and quantitatively with (E)-3-bromo-1,3-diphenylpropene and chlorotriphenylmethane. Substrate conversion decreases with decreasing substitution at the halogen-bearing carbon atom.

Full text of DOI:10.1021/om0000156

2844
Organometallics 2000, 19, 2844-2852
Tow a r d Meta l-Med ia ted C-F Bon d F or m a tion . Syn th esis
a n d Rea ctivity of th e 16-Electr on F lu or o Com p lex
[Ru F (d p p p )2]P F 6 (d p p p )
1,3-Bis(d ip h en ylp h osp h in o)p r op a n e)
Peter Barthazy, Robert M. Stoop, Michael Wo¨rle,† Antonio Togni,* and
Antonio Mezzetti*
Laboratory of Inorganic Chemistry, Swiss Federal Institute of Technology, ETH Zentrum,
CH-8092 Zu¨rich, Switzerland
Received J anuary 7, 2000
The five-coordinate fluoro complex [RuF(dppp)2]PF6 (1a ) has been prepared by reacting
[RuCl(dppp)2]PF6 (1b) with TlF (dppp ) 1,3-bis(diphenylphosphino)propane). An X-ray
investigation of 1a shows a distorted trigonal bipyramidal geometry (Y-shaped). The 16-
electron complex 1a reacts with a number of donors, including CO, H2, and F-. The X-ray
structure of trans-[RuF(CO)(dppp)2]PF6 (2a BPh4) suggests that the π-donor ability of the
fluoro ligand is only slightly higher than that of chloride. The reaction of 1a with [Me4N]F
gives cis-[RuF2(dppp)2] (3), a rare difluoro complex not stabilized by π-acidic co-ligands. The
Ru-F bond of 1a is hydrogenolyzed upon reaction with H2 to give [RuH(η2-H2)(dppp)2]+.
The coordinatively unsaturated complex 1a reacts with activated haloalkanes R-X (X ) Cl
or Br) in 1:1 molar ratio to give the fluorinated organic derivative and [RuX(dppp)2]+. The
halide metathesis proceeds instantaneously and quantitatively with (E)-3-bromo-1,3-
diphenylpropene and chlorotriphenylmethane. Substrate conversion decreases with decreas-
ing substitution at the halogen-bearing carbon atom.
In tr od u ction
fluoride salts8 or high-valent metal fluorides and oxof-
luorides.9 Although low-valent fluoro complexes of tran-
sition metals have long been known to react with
halogenated solvents,10 it has been shown only recently
that fluorinated organic products are formed thereby.11
Furthermore, coordination chemical aspects of fluorine
chemistry have constituted the object of systematic
Selective and efficient carbon-fluorine bond-forming
reactions evoke great interest in modern synthetic
chemistry, due to the importance of fluororganic com-
pounds both in medicinal chemistry and biochemistry.1
Whereas in recent years many fluorinating agents have
been developed, the use of transition metal complexes
has been very much focused on carbon-fluorine bond-
breaking processes.2-6 In contrast, investigations of
selective C-F bond formation are mainly restricted to
fluoroacyl complexes7 and to the use of low-valent
(8) Taverner, S. J .; Heath, P. A.; Clark, J . H. New J . Chem. 1998,
655, and references therein.
(9) (a) Dukat, W. W.; Holloway, J . H.; Hope, E. G.; Rieland, M. R.;
Townson, P. J .; Powell, R. L. J . Chem. Soc., Chem. Commun. 1993,
1429. (b) Holloway, J . H.; Hope, E. G.; Townson, P. J .; Powell, R. L. J .
Fluorine Chem. 1996, 76, 105.
* E-mail: mezzetti@inorg.chem.ethz.ch, togni@inorg.chem.ethz.ch.
† X-ray structures of complexes 1a , 2a , and 3.
(10) (a) Kemmitt, R. D. W.; Peacock, R. D.; Stocks, J . J . Chem. Soc.
A 1971, 846. (b) Cairns, M. A.; Dixon, K. R.; McFarland, J . J . J . Chem.
Soc., Dalton Trans. 1975, 1159.
(11) Fraser, S. L.; Antipin, M. Y.; Khroustslyov, V. N.; Grushin, V.
V. J . Am. Chem. Soc. 1997, 119, 4769. Pilon, M. C.; Grushin, V. V.
Organometallics 1998, 17, 1774. Grushin, V. V. Angew. Chem., Int.
Ed. 1998, 37, 994.
(12) Review articles: (a) Murphy, E. F.; Murugavel, R.; Roesky, H.
W. Chem. Rev. 1997, 97, 3425. (b) Doherty, N. M.; Hoffman, N. W.
Chem. Rev. 1991, 91, 553.
(13) (a) Poulton, J . T.; Sigalas, M. P.; Eisenstein, O.; Caulton, K. G.
Inorg. Chem. 1993, 32, 5490. (b) Poulton, J . T.; Sigalas, M. P.; Folting,
K.; Streib, W.; Eisenstein, O.; Caulton, K. G. Inorg. Chem. 1994, 33,
1476. (c) Cooper, A. C.; Folting, K.; Huffman, J . C.; Caulton, K. G.
Organometallics 1997, 16, 505. (d) Ogasawara, M.; Huang, D.; Streib,
W. E.; Huffman, J . C.; Gallego-Planas, N.; Maseras, F.; Eisenstein,
O.; Caulton, K. G. J . Am. Chem. Soc. 1997, 119, 8642.
(14) Veltheer, J . E.; Burger, P.; Bergman, R. G. J . Am. Chem. Soc.
1995, 117, 12478.
(1) See, for example: (a) Methods of Organic Chemistry (Houben-
Weyl), Organo-Fluorine Compounds; Baasner, B., Hagemann, H.,
Tatlow, J . C., Eds.; Thieme Verlag: Stuttgart, 1999; Vol. E10a, and
references therein. (b) ACS Monograph 187, Chemistry of Organic
Fluorine Compounds II; Hudlicky, M., Pavlath, A. E., Eds.; Americal
Chemical Society: Washington, DC, 1995. (c) Wilkinson, J . A. Chem.
Rev. 1992, 92, 505. (d) Selective Fluorination in Organic and Bioinor-
ganic Chemistry; Welch, T. J ., Ed.; ACS Symposium Series 456;
Americal Chemical Society: Washington, DC, 1990.
(2) Kiplinger, J . L.; Richmond, T. G.; Osterberg, C. E. Chem. Rev.
1994, 94, 373.
(3) Burdeniuc, J .; Siegbahn, P. E.; Crabtree, R. H. New. J . Chem.
1998, 503. Burdeniuc, J .; J edlicka, B.; Crabtree, R. H. Chem. Ber./
Recl. 1997, 130, 145.
(4) Braun, T.; Parsons, S.; Perutz, R. N.; Voith, M. Organometallics
1999, 18, 1710. Cronin, L.; Higgitt, C. L.; Karch, R.; Perutz, R. N.
Organometallics 1997, 16, 4920.
(5) Aizenberg, M.; Milstein, D. Science 1994, 265, 359. Aizenberg,
M.; Milstein, D. J . Am. Chem. Soc. 1995, 117, 9674.
(6) Kiplinger, J . L.; Richmond, T. G. J . Chem. Soc., Chem. Commun.
1996, 1115; J . Am. Chem. Soc. 1996, 118, 1805.
(7) (a) Brewer, S. A.; Coleman, K. S.; Fawcett, J .; Holloway, J . H.;
Hope, E. G.; Russell, D. R.; Watson, P. G. J . Chem. Soc., Dalton Trans.
1995, 1073. (b) Blake, A. J .; Cockman, R. W.; Ebsworth, E. A. V.;
Holloway, J . H. J . Chem. Soc., Chem. Commun. 1988, 529.
(15) Whittesley, M. K.; Perutz, R. N.; Greener, B.; Moore, M. H.
Chem. Commun. 1997, 187.
(16) (a) Coleman, K. S.; Fawcett, J .; Holloway, J . H.; Hope, E. G.;
Russell, D. R. J . Chem. Soc., Dalton Trans. 1997, 3557. (b) Cockman,
R. W.; Ebsworth, E. A. V.; Holloway, J . H.; Murdoch, H.; Robertson,
N.; Watson, P. G. In Inorganic Fluorine Chemistry; Thrasher, J . S.,
Strauss, S. H., Eds.; ACS Symposium Series 555; Americal Chemical
Society: Washington, DC, 1994.
10.1021/om0000156 CCC: $19.00 © 2000 American Chemical Society
Publication on Web 06/28/2000

Toward Metal-Mediated Bond Formation
Organometallics, Vol. 19, No. 15, 2000 2845
Ta ble 1. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for [Ru F (d p p p )2]P F 6 (1a )
Sch em e 1
Ru-F(1A)
Ru-P(1)
Ru-P(2)
2.030(7)
2.423(1)
2.261(1)
Ru-F(1B)
Ru-P(3)
Ru-P(4)
2.033(9)
2.408(1)
2.254(1)
F(1A)-Ru-P(1)
F(1A)-Ru-P(2)
F(1A)-Ru-P(3)
F(1A)-Ru-P(4)
P(1)-Ru-P(2)
P(1)-Ru-P(3)
P(1)-Ru-P(4)
88.8(2)
125.3(2)
82.9(2)
139.6(2)
89.41(4)
171.26(4)
96.51(4)
F(1B)-Ru-P(1)
F(1B)-Ru-P(2)
F(1B)-Ru-P(3)
F(1B)-Ru-P(4)
P(2)-Ru-P(3)
P(2)-Ru-P(4)
P(3)-Ru-P(4)
85.8(2)
145.5(2)
85.5(2)
119.7(2)
97.40(4)
94.85(4)
88.39(4)
studies only recently.12-17 In this context, we are
engaged in a fundamental study directed toward the
development of metal-mediated or metal-catalyzed fluo-
rination reactions. Clearly, to this goal a deeper knowl-
edge of the coordination chemistry of fluoride is re-
quired.
The π-donating ability of fluoride is found to stabilize
complexes of the early or middle transition metals.12 On
the other hand, the same effect explains the relative
instability of coordinatively saturated late transition
metal fluoro complexes, unless strong π-accepting ligands
are present. Thus, the π-donor fluoride is an excellent
candidate for stabilizing 16-electron complexes such as
[MX(P-P)2]n+ (M ) d6 metal center, X ) F).18,19 The
latter species adopts a distorted trigonal-bipyramidal
(Y-shaped) structure in order to optimize the X f M
π-donation (X ) Cl).18 However, five-coordinate fluoro
complexes with a 16-electron count are extremely rare.13
Furthermore, many of the reported fluoro phosphine
complexes are stabilized by strong π-acid co-ligands,
typically CO.7a,13,16,17
We report herein the synthesis and X-ray structures
of [RuF(dppp)2]+ (1a ) and cis-[RuF2(dppp)2] (3), contain-
ing the very rare FP4 and F2P4 donor sets,16b respec-
tively. Furthermore, we present the use of derivative
1a as a fluorinating agent for organic molecules con-
taining activated carbon-halide bonds. Part of this work
has appeared as a preliminary communication.20
F igu r e 1. ORTEP view of [RuF(dppp)2]PF6 (1a ) (30%
probability ellipsoids, only F(1A) is shown).
AA′MM′X spin system, CD2Cl2), which confirms the
presence of the fluoro ligand. The high-frequency dou-
blet of triplets at δ 49.0 is attributed to the equatorial
P atoms. The fluoride ligand is more strongly coupled
to the equatorial (J P,F ) 47.1 Hz) than to the axial P
atoms at δ -7.1 (J P,F ) 15.2 Hz). The 19F NMR spectrum
features the fluoro ligand as a triplet of triplets (X part
of AA′MM′X) at δ -203.4 with the same coupling
constants observed in the 31P NMR spectrum. As
already observed for a number of fluoro complexes,11 the
P,F coupling is not observed in CDCl3 containing traces
of water. Addition of activated molecular sieves to the
NMR samples in moist CDCl3 gives well-resolved 31P
and 19F NMR spectra. The Ru-F stretching mode of 1a
could not be identified in the IR spectrum.
The X-ray structure of [RuF(dppp)2]PF6 has been
determined, and selected interatomic distances and
angles are listed in Table 1. The metric data of cation
[RuF(dppp)2]+ are very similar to those of the chloro
analogue 1b.21 As expected for a π-stabilized 16-electron
complex,18 the equatorial plane shows a large deviation
away from the ideal trigonal-bipyramidal geometry,
with the P(2)-Ru-P(4) closed down to 94.85(4)° (Figure
1). As already observed in related species,18,19 the
Y-shaped coordination is further distorted, with unequal
F-Ru-Peq angles (Table 1). Both chelate rings have a
flattened chair conformation. The fluoride ligand is
disordered between two positions (F(1A) and F(1B), at
Resu lts a n d Discu ssion
[Ru F (d p p p )2]P F 6 (1a ). The five-coordinate species
[RuCl(dppp)2]PF6 (1b)19a reacts with TlF giving the red
fluoro analogue [RuF(dppp)2]PF6 (1a ) (Scheme 1). The
driving force for this metathesis reaction is the low
solubility of TlCl. Similarly to the chloro analogue 1b,
1a exhibits a static 31P spectrum (AA′MM′ part of a
(17) Ilg, K.; Werner, H. Organometallics 1999, 18, 5426.
(18) (a) Caulton, K. G. New J . Chem. 1994, 18, 25. (b) Riehl, J .-F.;
J ean, Y.; Eisenstein, O.; Pe´lissier, M. Organometallics 1992, 11, 729.
(c) J ohnson, T. J .; Folting, K.; Streib, W. E.; Martin, J . D.; Huffman,
J . C.; J ackson, S. A.; Eisenstein, O.; Caulton, K. G. Inorg. Chem. 1995,
34, 488, and references therein.
(19) See for instance: (a) Bressan, M.; Rigo, P. Inorg. Chem. 1975,
14, 2286. (b) Mezzetti, A.; Del Zotto, A.; Rigo, P.; Bresciani Pahor, N.
J . Chem. Soc., Dalton Trans. 1989, 1045. (c) Chin, B.; Lough, A. J .;
Morris, R. H.; Schweitzer, C. T.; D’Agostino, C. Inorg. Chem. 1994,
33, 6278. (d) de los Rios, I.; J ime´nez-Tenorio, M.; Puerta, M. C.; Salcedo,
I.; Valerga, P. J . Chem. Soc., Dalton Trans. 1997, 4619.
(20) Barthazy, P.; Hintermann, L.; Stoop, R. M.; Wo¨rle, M.; Mezzetti,
A.; Togni, A. Helv. Chim. Acta 1999, 82, 2448.
(21) Batista, A. A.; Centeno Cordeiro, L. A.; Oliva, G. Inorg. Chim.
Acta 1993, 203, 185.

2846 Organometallics, Vol. 19, No. 15, 2000
Barthazy et al.
0.728(9) Å from each other) approximately lying in the
equatorial plane. Resolved electron density maxima for
the disordered halide ligand were obtained in the
Fourier map from diffraction data collected at -60 °C.22
The similar occupancies of the two F sites (46 and 40%
for F(1A) and F(1B), respectively) suggest similar ener-
gies for both positions. A minor electron density peak
is interpreted as isomorphic substitution of F with Cl
(14% of total), which is apparently due to partial F/Cl
exchange during crystallization, as confirmed by 31P
NMR.23 The Ru-Cl distance (2.315(11) Å) is close to the
value found in 1b (2.371(5) Å).21
Analysis of the nonbonded contacts reveals that the
positional disorder maximizes the F‚‚‚H hydrogen bonds
to the six phenyl rings forming a pocket around the
halide ligand in both 1a and 1b. Comparison of the
X-ray structures of 1b and 1a shows that, on going from
Cl to F, a twist of the axial phenyls C(7)-C(12) and
C(31)-C(36) reduces the nonbonded distances between
the ortho H atoms and X (X ) Cl and F, respectively)
from values in the range 2.49-2.99 Å in 1b to 2.17-
2.59 Å in 1a . As will be discussed below, other fluoro
complexes exhibit nonbonded F‚‚‚H distances signifi-
cantly shorter than the sum of the van der Waals radii
(2.67 Å).16 The P(1)-Ru-P(3) angle between the trans
Pax atoms is closed down to 171.26(4)°, probably as an
effect of both the steric crowding due to the large bite
angle of dppp (close to 90°) and the attractive F‚‚‚H
interaction.
F igu r e 2. ORTEP view of [RuF(CO)(dppp)2]BPh4 (2a )
(30% probability ellipsoids).
Ta ble 2. Selected In ter a tom ic Dista n ces (Å) a n d
An gles (d eg) for [Ru F (CO)(d p p p )2]P F 6 (2a )
Ru-F(1)
2.069(2)
2.433(1)
2.424(1)
1.152(5)
2.29
Ru-C(55)
Ru-P(3)
Ru-P(4)
1.830(4)
2.434(1)
2.426(1)
Ru-P(1)
Ru-P(2)
C(55)-O(1)
F(1)‚‚‚H(8)
F(1)‚‚‚H(32)
The Ru-F distance deserves particular attention as
a diagnostic tool for the extent of the π-donation.
Unfortunately, large standard deviations are associated
with the positional parameters of F(1A) and F(1B) due
to partial overlap of their electron densities, and caution
is required in discussing the Ru-F bond distances
(2.030(7) and 2.033(9) Å, respectively). Taking as refer-
F(1)‚‚‚H(24)
F(1)‚‚‚H(48)
2.52
2.51
2.29
F(1)-Ru-C(55)
F(1)-Ru-P(1)
F(1)-Ru-P(2)
F(1)-Ru-P(3)
F(1)-Ru-P(4)
C(55)-Ru-P(1)
C(55)-Ru-P(2)
C(55)-Ru-P(3)
179.7(1)
95.67(7)
81.61(7)
94.20(7)
82.35(7)
84.6(1)
C(55)-Ru-P(4)
P(1)-Ru-P(2)
P(1)-Ru-P(3)
P(1)-Ru-P(4)
P(2)-Ru-P(3)
P(2)-Ru-P(4)
P(3)-Ru-P(4)
97.8(1)
86.07(4)
170.13(4)
95.19(4)
95.15(4)
163.96(4)
86.36(4)
ence the Ru-Cl distance of 2.371(5) Å in 1b,21
a
98.2(1)
85.5(1)
calculated value of 2.02 Å is obtained by subtracting the
difference of the atomic radii of F and Cl (0.35 Å). The
closeness of observed and calculated values suggests
that the π-contribution to the bonding is similar in 1a
and 1b. The Ru-P distances are very similar to those
of 1b, with Ru-Pax much longer than Ru-Peq. This is
expected on the basis of trans influence effects and is
reflected in the 31P NMR shifts (see above).
caused by the large bite angle of the dppp ligand (see
below). In the 19F NMR spectrum, a broad singlet at δ
-401 confirms the presence of the fluoro ligand.
The ν(CO) stretching frequency of 2a PF6 (1944 cm-1
,
KBr) is lower than that of the chloro analogue [RuCl-
(CO)(dppp)2] (2b)19a (1953 cm-1, KBr). This follows the
trend observed for other complexes containing an X-M-
CO fragment (X ) halide), which has been explained
by assuming that fluoride is a better π-donor than its
heavier analogues.12b,16 Also, it has been argued that
the lone pairs of the fluoride ligands destabilize the
metal orbitals having the appropriate π-symmetry (dxz
and dyz assuming the F-Ru-CO vector as the z axis).
This four-electron repulsion is larger with fluoride than
with the heavier halides, which enhances the π-back-
donation to the carbonyl ligand (push-pull interaction)
in the fluoro analogue.18a To get further insight into
these effects, we have determined the X-ray structure
of the tetraphenylborate salt 2a BPh4.
[Ru F (CO)(d p p p )2]P F 6 (2a P F 6). In agreement with
its unsaturated nature, complex 1a reacts with a
number of donors. The reaction with CO is instanta-
neous in CH2Cl2, and yields trans-[RuF(CO)(dppp)2]PF6
(2a PF6) (Scheme 1).24 Complex 2a PF6 features a broad
singlet at δ 3.0 in the 31P NMR spectrum. Similarly
broadened signals have been previously observed for the
related six-coordinate complexes trans-[RuCl(η2-H2)-
(dppp)2]+25 and are probably due to the inversion at
ruthenium in the tetrahedrally distorted RuP4 plane
(22) At room temperature the maxima are not resolved.
(23) In view of the reactivity of 1a with alkyl halides, the F/Cl
exchange is apparently not due to the reaction of 1a with CH2Cl2, but
rather to traces of HCl (see below). Attempts at growing suitable
crystals in other solvents were unsuccessful.
(24) (a) There is no evidence of the formation of the cis isomer as
intermediate.24b (b) Mezzetti, A.; Del Zotto, A.; Rigo, P. J . Chem. Soc.,
Dalton Trans. 1990, 2515.
The [RuF(CO)(dppp)2]+ cation has a distorted octa-
hedral geometry with pseudo-C2 symmetry (Figure 2,
Table 2). The trans P-Ru-P angles (170.13(4)° and
163.96(4)°) deviate largely from the ideal value, result-
ing in a tetrahedral distortion of the P4 plane: P(1) and
P(3) are off the mean plane by 0.275 and 0.274 Å, and
P(2) and P(4) by 0.275 and 0.274 Å on the opposite side.
(25) Rocchini, E.; Mezzetti, A.; Ru¨egger, H.; Burckhardt, U.; Gram-
lich, V.; Del Zotto, A.; Martinuzzi, P.; Rigo, P. Inorg. Chem. 1997, 36,
711.

Toward Metal-Mediated Bond Formation
Organometallics, Vol. 19, No. 15, 2000 2847
Ta ble 3. Selected IR a n d X-r a y Da ta for 2a , 2c, a n d [Ru F 2(CO)2(P P h 3)2
[RuF(CO)(dppp)2]+
[RuCl(CO)(dppm)2]+
(2a )
(2c)a
[RuF2(CO)2(PPh3)2]b
ν(CO), cm-1
d(Ru-X), Å
d(Ru-C), Å
d(C-O), Å
1944c
2.069(2)
1.830(4)
1.152(5)
1973d
2.422(3)
1.849(9)
1.11(1)
2045, 1973d
2.011(4)
1.841(7)
1.135(9)
a
b
d
From ref 26. From ref 16a. c In KBr. In Nujol.
This is apparently due to steric crowding, as indicated
by the twist conformation of the chelate rings. Two
phenyl rings are involved in short nonbonded distances
between the fluoro ligand and the ortho H atoms H(8)
and H(32) (2.29 Å, Table 2). As the covalent radius of
ruthenium remains nearly constant on going from five-
coordinate 1a to six-coordinate 2a (the Ru-P distances
involving mutually trans phosphines increase by only
ca. 0.01 Å), the Ru-F distances in 1a and 2a (2.03 and
2.07 Å, respectively) suggest that the F f Ru π-bonding
is stronger in the former complex. The experimental
Ru-F distance in 2a is identical to the value calculated
by subtracting the difference between the covalent radii
of Cl and F (0.35 Å) from the Ru-Cl distance in the
closely related chloro carbonyl complex [RuCl(CO)-
(dppm)2]+ (2c, dppm ) bis(diphenylphosphino)methane)
(2.42 Å).26 This would suggest that both the fluoro
carbonyl 2a and the chloro analogue 2c feature push-
pull interactions of comparable magnitude, whereas
comparison of the Ru-C (and C-O) distances suggests
that metal-to-carbonyl back-bonding is stronger in the
case of the fluoro derivative 2a (Table 3).27
F igu r e 3. Experimental (above) and simulated (below) 31
(AA′, MM′) and 19F (XX′) NMR spectra of 3.
P
Comparison with complexes of the type cis,cis,trans-
[RuF2(CO)2(PPh3)2]16 is less useful due to the different
charge of the complex (0 vs +1) and to the different
donor sets (F2(CO)2P2 vs F(CO)P4). The data in Table 3
indicate a higher degree of Ru f CO π-back-donation
(but a weaker F f Ru π-bond) in 2a than in [RuF2(CO)2-
(PPh3)2]. This suggests that the presence of a second
carbonyl ligand in [RuF2(CO)2(PPh3)2] enhances the
competition for the dπ-electrons of ruthenium, leading
to a lower Ru-C bond order (and higher Ru-F bond
order) than in 2a .
Ta ble 4. Selected In ter a tom ic Dista n ces (Å) a n d
An gles (d eg) for [Ru F 2(d p p p )2] (3) (m olecu le 1)
Ru(1)-F(1)
Ru(1)-P(1)
Ru(1)-P(3)
F(1)‚‚‚H(18)
F(1)‚‚‚H(44)
2.069(3)
2.399(2)
2.389(2)
2.09
Ru(1)-F(2)
Ru(1)-P(2)
Ru(1)-P(4)
F(2)‚‚‚H(24)
F(2)‚‚‚H(38)
2.056(3)
2.310(2)
2.303(2)
2.08
2.12
2.07
F(1)-Ru(1)-F(2)
F(1)-Ru(1)-P(1)
F(1)-Ru(1)-P(2)
F(1)-Ru(1)-P(3)
F(1)-Ru(1)-P(4)
P(1)-Ru(1)-P(2)
P(1)-Ru(1)-P(3)
P(1)-Ru(1)-P(4)
78.2(1)
85.5(1)
170.5(1)
86.2(1)
93.53(9)
90.93(6)
169.72(5)
95.81(6)
F(2)-Ru(1)-P(1)
F(2)-Ru(1)-P(2)
F(2)-Ru(1)-P(3)
F(2)-Ru(1)-P(4)
P(2)-Ru(1)-P(3)
P(2)-Ru(1)-P(4)
P(3)-Ru(1)-P(4)
87.1(1)
92.90(9)
85.3(1)
171.00(9)
96.32(6)
95.57(6)
90.75(6)
[Ru F 2(d p p p )2] (3). Complex 1a reacts with [Me4N]F
(1.8 equiv) in CH2Cl2 giving cis-[RuF2(dppp)2] (3) (Scheme
1). Complex 3 is a rare example of a six-coordinate
difluoro complex of a d6 metal center that does not
contain strong π-acceptor ligands, such as CO.16b The
31P and 19F NMR spectral pattern of 3 (AA′MM′XX′ spin
system) is indicative of a cis configuration (Figure 3).
The AA′ part at δ 30.9 is attributed to the P atoms trans
to F, and the mutually trans P atoms (MM′) show their
resonance at δ 1.3. The 19F NMR spectrum features the
fluoro ligands (XX′ part of AA′MM′XX′) at δ -341.6.
Simulation of both 31P and 19F NMR spectra yielded the
chemical shifts and coupling constants (Figure 3). Two
bands of medium intensity at 443 and 414 cm-1 in the
IR spectrum are attributed to the Ru-F stretching
vibration.28
Complex 3 has been studied by X-ray crystallography.
The unit cell contains two crystallographically indepen-
dent molecules, together with CH2Cl2 and hexane as
solvent of crystallization. The structural parameters of
the two independent molecules are essentially identical
within standard deviations (Table 4). The coordination
polyhedron is a distorted octahedron with mutually cis
F atoms (Figure 4). The F-Ru-F angle is closed down
to 78° as an effect of the steric bulk of the dppp ligands,
which is also manifested in the trans P-Ru-P angle
(ca. 170°). The conformation of both chelate rings is
chair as in 1a , whereas in 2a both chelates have twist
(26) Szczepura, L. F.; Giambra, J .; See, R. F.; Lawson, H.; J anik, T.
S.; J ircitano, A. J .; Churchill, M. R.; Takeuchi, K. J . Inorg. Chim. Acta
1995, 239, 77.
(27) The X-ray data of [RuCl(CO)(dppe)2]+ (dppe ) 1,2-bis(di-
phenylphosphino)ethane), in which the Cl and CO ligands are disor-
dered, are not discussed in view of the large errors of the Ru-Cl, Ru-
C, and C-O distances.26
(28) Nakamoto, K. Infrared and Raman Spectra of Inorganic and
Coordination Compounds; Wiley: New York, 1995; Part B, p 265.

2848 Organometallics, Vol. 19, No. 15, 2000
Barthazy et al.
some discussion. The stereochemical course of CO and
halide addition to the related five-coordinate species
[MX(dcpe)2]+ (M ) Ru or Os; X ) Cl- or Br-; dcpe )
1,2-bis(dicyclohexylphosphino)ethane) has been studied
as a function of the reaction temperature.24b Below room
temperature, both CO and halide ions give cis attack,
in agreement with the P donor having a higher trans
effect than halide. The resulting cis-[MX(L)(dcpe)2]n+ (n
) 1 or 0) adducts are stable at low temperature, but
isomerize at room temperature, giving trans-[MX(L)-
(dcpe)2]n+. When L is Cl-or Br-, the isomerization
reaction occurs by halide dissociation, followed by (slow)
trans attack to give the kinetically inert trans isomer
(eqs 1 and 2). In the case of the fluoro analogue 1a , the
cis-[MX2(P-P)2] h [MX(P-P)2]+ + X-
(1)
[MX(P-P)2]+ + X- f trans-[MX2(P-P)2]+ (2)
addition of the sixth ligand L apparently occurs with
different stereochemistry depending on L, the attack
being trans for L ) CO and cis for L ) F-. However,
the trans-carbonyl adduct might be formed by fast
isomerization of an initially formed, but undetected cis
adduct. Accordingly, in the case of [RuCl(dcpe)2]+, the
initially formed cis-[RuCl(CO)(dcpe)2]+ isomerizes at
room temperature to give the thermodynamically stable
and kinetically inert trans-[RuCl(CO)(dcpe)2]+.24b The
preference for the cis attack is evident in the reaction
of 1a with F-. However, at difference with cis-[RuX2-
(dcpe)2] (X ) Cl, Br),24b the cis-difluoro complex 3 does
not dissociate one fluoride at room temperature in CH2-
Cl2; that is, equilibrium 1 is completely shifted to the
left when X is fluoride. An alternative explanation of
the inability of 3 to undergo cis-trans isomerization
might be related to the poor stability of the trans isomer
caused by strong electron repulsion along the F-Ru-F
axis.18a
F igu r e 4. ORTEP view of cis-[RuF2(dppp)2] (3) (30%
probability ellipsoids).
conformations, which is indicative of larger steric crowd-
ing. The Ru-F distances in 3 (average 2.06 Å) are
significantly longer than in five-coordinate 1a (average
2.03 Å) and slightly shorter than in 2a (2.069(2) Å). The
latter comparison suggests that the carbonyl ligand has
a slightly larger trans influence toward the Ru-F bond
than the phosphine. This contrasts with the trends
observed for the trans influence toward the Ru-Cl bond
in six-coordinate Ru(II) complexes.29
Furthermore, four ortho H atoms of two axial and two
equatorial phenyl rings of the first independent mol-
ecule are involved in short F‚‚‚H contacts in the range
2.07-2.12 Å (the sum of the van der Waals radii is 2.67
Å) (Table 4, Figure 4).30 The complexes [RuF2(CO)2-
(PPh3)2] show similar features.16a,31 The fluoro ligands
of the second independent molecule form four hydrogen
bonds to phenyl H atoms (F‚‚‚H distances between 2.07
and 2.12 Å) and one to a (nondisordered) CH2Cl2
molecule with a F(4)‚‚‚H distance of 2.10 Å. The
shortening of the H‚‚‚F contacts on going from 1a to 2a
and 3 reflects the increase both of the steric hindrance
in the complexes and of the basicity of the F lone pairs
(see below).
Complex 3 is more sensitive to traces of water than
1a and must be protected from air moisture. Therefore,
3 was manipulated in a glovebox under purified nitro-
gen. In solution, exposure to traces of water leads to
decomposition to unidentified products. Thus, the re-
activity of the fluoro complexes on going from a 16-
electron (1a ) to an 18-electron complex (3) reflects the
increase in the four-electron repulsion in this series.
This shows that coordination to a metal fragment allows
tuning the nucleophilic properties of the fluoride anion.
Finally, the stereochemistry of ligand attack onto five-
coordinate 1a to give the difluoro complex 3 deserves
Rea ction of [Ru F (d p p p )2]+ w ith H2. The five-
coordinate chloro complexes [MCl(P-P)2]+ (M ) Ru, Os)
are known to react with H2 to give the elongated
dihydrogen complexes [MCl(η2-H2)(P-P)2]+.25,32 In the
case of the dppp derivative 1b, the H2-addition reaction
is an equilibrium (K ) 0.7 × 10-2 at 23 °C).25 To
investigate further the electronic effects of fluoride as
compared to the other halides, we have studied the
reaction of 1a with H2. Complex 1a was dissolved in
CDCl3 in an NMR tube fitted with a Young valve, which
was filled with H2 (after evacuation) at room tempera-
ture. The solution color turns from red to yellow upon
shaking the NMR tube in order to saturate the solvent
1
with H2. The H and 31P NMR spectra of the reaction
solution showed the signals of the already known [RuH-
(η2-H2)(dppp)2]+ (4).33 A broad signal in the 19F NMR
spectrum of the reaction mixture indicated that HF is
formed.
(32) Cappellani, E. P.; Maltby, P. A.; Morris, R. H.; Schweitzer, C.
T.; Steele, M. R. Inorg. Chem. 1989, 28, 4437. Mezzetti, A.; Del Zotto,
A.; Rigo, P.; Farnetti, E. J . Chem. Soc., Dalton Trans. 1991, 1525.
Burrell, A. K.; Bryan, J . C.; Kubas, G. J . J . Am. Chem. Soc. 1994, 116,
1575. Chin, B.; Lough, A. J .; Morris, R. H.; Schweitzer C. T.; D’Agostino,
C. Inorg. Chem. 1994, 33, 6278. Maltby, P. A.; Schlaf, M.; Steinbeck,
M.; Lough, A. J .; Morris, R. H.; Klooster, W. T.; Koetzle, T. F.;
Srivastava, R. C. J . Am. Chem. Soc. 1996, 118, 5396.
(29) Brown, L. D.; Barnard, C. F. J .; Daniels, J . A.; Mawby, R. J .;
Ibers, J . A. Inorg. Chem. 1978, 17, 2932.
(30) The actual nonbonded distances are even shorter, as the F‚‚‚
H-Cphenyl distances are calculated assuming an apparent C-H distance
of 0.93 Å.
(31) Intramolecuar N-H‚‚‚F bonds have been used to stabilize
M(HF) complexes. See: Lee, D.-H.; Kwon, H. J .; Patel, B. P.; Liable-
Sands, L. M.; Rheingold, A. L.; Crabtree, R. H. Organometallics 1999,
18, 1615.
(33) Saburi, M.; Aoyagi, K.; Takahashi, T.; Uchida, Y. Chem. Lett.
1990, 601.

Toward Metal-Mediated Bond Formation
Organometallics, Vol. 19, No. 15, 2000 2849
Ta ble 5. Rea ction s of 1a w ith R-X (5a -e)a
Sch em e 2
reaction
time
conv
(%)
selectivity
(%)
run
substrate
refb
20
35, 36
36, 37
36, 38
1
2
3
4
5
5a
5b
5c
5d
5e
1 min
1 min
18 h
1 dc
100
100
70
50
75
90
100
>90
6
20
d
1 d
a
Reaction conditions: 1a (22 mg, 20 µmol) and 1 equiv of R-X
(5a -e) (R ) Br or Cl) were dissolved in CDCl3 in a Teflon-coated
NMR tube at room temperature (unless otherwise stated). Conver-
sion is based on 5, and selectivity is the percentage of converted
b
5 that forms 6a -d . Fluorinated products were identified by
comparison of the 19F NMR data with literature values from cited
papers. c At 50 °C. Several unidentified products.
d
Although the preparation of a fluoro dihydrogen
complex seemed possible in view of the relative kinetic
inertness of the Ru-F bond in these complexes, the
reaction of 1a with H2 gives the hydrogenolysis product
[RuH(η2-H2)(dppp)2]+ (4) (Scheme 1). This reaction is
driven thermodynamically by the formation of HF and
may involve an intermediate fluoro dihydrogen complex.
It has been recently proposed34 that the acidity of the
putative dihydrogen complex [RuF(η2-H2)(dppp)2]+ should
be close to that of [RuCl(η2-H2)(dppp)2]+ (pKa is ca. 4).25
Thus, the elimination of HF can be mediated by in-
tramolecular proton transfer from the dihydrogen ligand
to the more basic fluoride, followed by elimination. Also
[RuH(F)(CO)(PtBu2Me)2] has a labile Ru-F bond that
is readily hydrogenolyzed.13a
spectrum with the signal of the [PF6]- as reference (run
2). The 31P NMR spectrum shows that 1c is formed
quantitatively.
The reaction of 1a with bromodiphenylmethane (5c)
is much slower and not quantitative (run 3). The 1H
NMR spectrum of the reaction solution indicates that
70% of starting 5c has reacted after 18-h reaction time
at room temperature. The fluorinated product 6c is
formed with high selectivity, as shown by integration
of the doublet at δ 6.48. The remaining converted
substrate gives trace amounts of bis(diphenylmethyl)
1
ether, as indicated by the H NMR singlet at δ 5.40.39
The gate-decoupled 19F NMR spectrum confirms that
only 6c contains fluorine. Integration of the spectrum
with [PF6]- as reference is consistent with the yield of
F lu or in a tion Rea ction s. The fluoro ligand in com-
plex 1a can be transferred to activated organic electro-
philes R-X (X ) Br or Cl). The overall reaction is a
halide metathesis that yields R-F and [RuX(dppp)2]+
(Scheme 2). In a typical procedure, complex 1a and the
corresponding substrate 5a -e (1 equiv) were dissolved
in CDCl3 in an NMR tube fitted with a Teflon liner and
a Young valve. All manipulations were performed under
purified nitrogen in a glovebox. The reaction was
1
6c obtained from the H NMR spectrum.
tert-Butyl bromide 5d is even less reactive (50%
conversion after 1 day at 50 °C, run 4) and gives lower
selectivity to (CH3)3CF (20%), as determined by integra-
1
tion of the H NMR spectrum. The main product is the
elimination product isobutene (75% selectivity). A low-
intensity singlet at δ 1.28 is attributed to (CH3)3COC-
(CH3)3 (<5%) on the basis of its chemical shift40 and by
analogy with the reaction with 5a , in which small
amounts of the corresponding ether were detected.20
Finally, (E)-3-bromo-1-phenylpropene 5e forms a num-
ber of yet unidentified fluorinated organic products.
Under the same conditions, 3-bromopropene and 2-
iodopropane do not react over longer reaction times (3-7
days) at temperatures between 20 and 50 °C.
The substrates tested show a clear reactivity trend.
Substrate conversion increases with increasing substi-
tution at the halogen-bearing carbon in the case of both
phenyl and alkyl groups. Thus, Ph3CBr (5b) is more
reactive than Ph2CHBr (5c). In the alkyl series, the
reaction of tert-butyl bromide is fast, whereas 2-iodopro-
pane is completely unreactive. Increasing the size of the
conjugated system has a similar effect: 1,3-Diphenyla-
llyl bromide (5a ) is more reactive than 5e, but 3-bro-
mopropene does not react. The F/Cl exchange observed
upon standing of 1a in CH2Cl2 deserves a final com-
ment. Since 1a does not react with allyl bromide and
2-iodopropane, which are stronger electrophiles than
CH2Cl2, it is probable that the chlorination is due to the
presence of traces of HCl formed from the chlorinated
solvent upon standing rather than to direct reaction
with CH2Cl2. In contrast to five-coordinate 1a , the cis-
1
monitored by H, 31P, and 19F NMR spectroscopy. The
identity of the fluorinated products was determined by
19F NMR spectroscopy by comparison with literature
data.20,35-38 Table 5 provides an overview of the reac-
tions of 1a with a number of alkyl bromides (or chloride)
to give the corresponding fluorinated products. Conver-
sion data are based on bromo derivative 5 and were
determined as described below. The reaction of 5a with
1a occurs within seconds after mixing, as indicated by
the immediate color change from red to brown. The 19F
NMR spectrum of the reaction mixture shows that 6a
is the only fluorinated species besides [PF6]-. Integra-
tion of the 1H NMR spectrum (see Experimental Section)
indicates that 6a is formed quantitatively (Table 5, run
1). The bromo derivative [RuBr(dppp)2]PF6 (1c)19a is the
only complex present after completion of the reaction,
as detected by 31P NMR spectroscopy. Also triphenyl-
chloromethane 5b reacts quantitatively to 6b, as indi-
cated by integration of the gate-decoupled 19F NMR
(34) Xu, Z. T.; Bytheway, I.; J ia, G. C.; Lin, Z. Y. Organometallics
1999, 18, 1761.
(35) Cox, D. P.; Terpinski, J .; Lawrynowicz, W. J . Org. Chem. 1984,
49, 3216.
(36) Lai, C.; Kim, Y. I.; Wang, C. M.; Mallouk, T. E. J . Org. Chem.
1993, 58, 1393.
(37) York, C.; Surya Prakash, G. K.; Olah, G. A. Tetrahedron 1996,
52, 9.
(38) Olah, G. A.; Baker, E. B.; Evans, J . C.; Tolgyesi, W. S.; McIntyre,
J . S.; Bastien, I. J . J . Am. Chem. Soc. 1964, 86, 1360.
(39) Mizuno, H.; Matsuda, M.; Iino, M. J . Org. Chem. 1981, 46, 520.
(40) King, J . F.; Lam, J . Y. L.; Dave, V. J . Org. Chem. 1995, 60,
2831.

2850 Organometallics, Vol. 19, No. 15, 2000
Barthazy et al.
was determined by integration of a one-pulse 1H NMR
spectrum. Yield: 725 mg (90%). H NMR (CDCl3): δ 7.82 (s,
difluoro complex 3 (formed in situ from 1a and CsF) does
not react with 5b. Thus, coordinative unsaturation is
apparently necessary in order to trigger halide metath-
esis. We tentatively suggest that 1a acts as a Lewis acid
toward the alkyl bromide 5, as well as a donor of fluoride
and bromide scavenger. Fluorine exchange reactions
between fluoro complexes and alkyl halides are not new.
The reaction of fluoro complexes of Pt and Pd with
chlorinated solvents has been shown to give the corre-
sponding chloro complex.10,11 However, the nature of the
organic product has rarely been ascertained, and the
synthetic potential of this reaction has not been explored
yet. One recent example is [PdF(Ph)(PPh3)2], which
forms a mixture of CH2ClF and CH2F2 by reaction with
CH2Cl2 within hours.11b Although high-valent metal
fluorides and oxofluorides have been used for similar
transformations,9 the systematic use of well-defined,
low-valent fluoro complexes of a transition metal for
selective C-F bond formation reactions under mild
conditions is unprecedented. We are exploring further
applications of 16-electron fluoro complexes of ruthe-
nium in organic synthesis.
1
br, 8 H, PhH), 6.8-7.5 (m, 32 H, PhH), 2.62 (s, br, 4 H, PCH2),
2.0-2.5 (m, 4 H, PCH2), 1.58 (s, br, 4 H, CH2). 31P NMR
(CDCl3): δ 49.0 (d × t, 2 P, Ru-P, J P,F ) 47.1 Hz, J P,P′ ) 31.9
Hz), -7.1 (t × d, 2 P, Ru-P, J P,F ) 15.2 Hz, J P,P′ ) 31.9 Hz),
-143.1 (septet, J P,F ) 710 Hz, 1 P, PF6). 19F NMR: δ -74.5
(d, 6 F, J P,F ) 710 Hz, PF6), -203.6 (t × t, J P,F ) 47 Hz, J P′,F
) 15 Hz, 1 F, RuF). MS (FAB+): m/z 945 ([M]+, 100%), 511
([M - dppp]+, 35%). Anal. Calcd for C54H52F7P5Ru‚0.5 CH2-
Cl2: C, 57.81; H, 4.72. Found: C, 57.81; H, 4.82.
[Ru Br (d p p p )2]P F 6 (1c). As in ref 18a. Further data: 1H
NMR (CDCl3): δ 7.8-7.9 (m, 4 H, PhH), 7.1-7.6 (m, 24 H,
PhH), 6.8-7.0 (m, 8 H, PhH), 2.9-3.0 (m, 2 H, CH2), 2.6-2.7
(m, 2 H, CH2), 2.1-2.5 (m, 4 H, CH2), 1.6-1.7 (m, 2 H, CH2),
0.8-0.9 (m, 2 H, CH2). 31P NMR: δ 43.5 (t, 2 P, J P,P′ ) 32 Hz),
-4.4 (t, 2 P, J P,P′ ) 32 Hz), -143 (septet, J P,F ) 710 Hz, PF6).
MS (FAB+): m/z 1007 ([M + H]+, 100), 926 ([M - Br]+, 6),
511 ([Ru(dppp)]+, 5).
[Ru F (CO)(d p p p )2]P F 6 (2a P F 6). Compound 1a (27 mg,
0.025 mmol) was dissolved in CH2Cl2 (10 mL), and CO gas
was bubbled through the solution for 2 h. After adding PriOH
(20 mL) and hexane (20 mL) to the colorless solution, CH2Cl2
was removed under vacuum. The resulting white powder was
filtered off. The presence of CH2Cl2 (0.5 mol per mol of 2a P F 6)
was determined by integration of a one-pulse 1H NMR
spectrum. Yield: 20 mg (72%). 1H NMR (CDCl3): δ 7.60 (s,
br, 8 H, PhH), 7.45 (t, 4 H, J H,H′ ) 7.4 Hz, PhH), 7.17-7.32
(m, 20 H, PhH), 6.9-7.1 (m, 8 H, PhH), 2.6-2.8 (m, 4 H,
PCH2), 2.2-2.4 (m, 4 H, PCH2), 1.9-2.2 (m, 2 H, CH2), 1.4-
1.6 (m, 2 H, CH2). 31P NMR (CDCl3): δ 3.0 (br, 4 P, RuP),
-143.1 (septet, J P,F ) 710 Hz, 1 P, PF6). 19F NMR: δ -74.5
(d, 6 F, J P,F ) 710 Hz, PF6), -400.8 (s, br, 1 F, RuF). IR (KBr,
cm-1): 1944, ν(CO), 842, ν(P-F). MS (FAB+): m/z 973 ([M]+),
561 ([M - dppp]+), 511 ([Ru - dppp]+), 335 ([dppp - Ph]+).
Anal. Calcd for C55H52OF7P5Ru‚PriOH‚0.5 CH2Cl2: C, 57.57;
H, 5.04. Found: C, 57.70; H, 5.00.
Con clu sion
A formally coordinatively unsaturated, 16-electron
fluoro complex of a relatively soft metal ion, such as
ruthenium(II), is a stable species that reacts with an
activated organic bromide to form a C-F bond. Al-
though not yet of practical significance, the use of fluoro
complexes containing diphosphine ligands in fluorina-
tion reactions clearly allows the transport of fluoride
ions in organic solvents and their reaction with organic
halides under mild conditions and opens new ways for
asymmetric C-F bond formation.
[Ru F 2(d p p p )2] (3). Compound 1a (190 mg, 0.175 mmol) and
[NMe4]F (33 mg, 0.35 mmol) were dissolved in CH2Cl2 (20 mL).
After stirring for 1 day at room temperature, [NMe4]PF6 was
filtered off and CH2Cl2 was removed under vacuum. The
residue was dissolved in CH2Cl2 (10 mL) and filtered to remove
traces of [NMe4]PF6. The solution was treated with hexane
(20 mL), and the CH2Cl2 was evaporated. The resulting light
yellow powder was filtered off. Yield: 143 mg (85%). The
presence of CH2Cl2 and C6H14 (according to the composition
3‚C6H14‚CH2Cl2) was determined by integration of a one-pulse
1H NMR spectrum. 1H NMR (CDCl3): δ 8.0-8.2 (s, br, 4 H,
Ph-H), 7.6-7.9 (m, br, 8 H, Ph-H), 6.7-7.6 (m, 28 H, Ph-
H), 0.9-2.8 (m, 12 H, P-CH2). 31P NMR (CDCl3): δ 30.9
(AA′MM′XX′, equatorial P, 2 P, J A,A′ ) -27.2 Hz, J AM ) -32.5
Hz, J A,M′ ) -35.0 Hz, J A,X ) 155.9 Hz, J A,X′ ) 3.7 Hz), 1.3
(AA′MM′XX′, apical P, 2 P, J A,M ) -32.5 Hz, J A,M′ ) -35.0
Hz, J M,M′ ) 173.9 Hz, J M,X ) -16.2 Hz, J M,X′ ) -24.3 Hz),
-143.1 (septet, J P,F ) 710 Hz, 1 P, PF6). 19F NMR (CDCl3): δ
-341.6 (AA′MM′XX′, 2F, Ru-F, J A,X ) 155.9 Hz, J A,X′ ) 3.7
Hz, J M,X ) -16.2 Hz, J M,X′ ) -24.3 Hz, J X,X′ ) -161.0 Hz).
MS (FAB+): m/z 945 ([M - F]+). Anal. Calcd for C55H52OF7P5-
Ru‚C6H14‚CH2Cl2: C, 64.55; H, 6.04. Found: C, 64.35; H, 5.89.
IR (KBr, cm-1): 443, 414, ν(Ru-F).
Exp er im en ta l Section
Gen er a l Com m en ts. All operations were carried out under
argon using standard Schlenk techniques. All reagents and
solvents were Fluka puriss. grade or had comparable purity.
Diphenylallyl bromide was prepared according to a literature
procedure,41 and the fluoro analogue (E)-3-fluoro-1,3-diphe-
nylpropene as previously described.20 NMR spectra were
recorded on Bruker Avance 250 (1H, 31P) and 300 (19F)
spectrometers. Chemical shifts δ are in ppm relative to
internal SiMe4 (1H, 13C) and to external 85% H3PO4. 19F NMR
spectra are referenced to CFCl3. Simulations of the 31P and
19F NMR spectra of 3 were performed with the programs
WINDAISY and WIN-NMR (Bruker Spectrospin). The spin
system was defined as AA′MM′XX′ (31P part AA′MM′, 19F part
2
XX′) assuming positive trans J coupling constants and nega-
tive cis ones. However, J A,X′ refined to a small positive value
of 3.7 Hz. A line broadening of 7.5 Hz was used. Infrared
spectra were recorded on a Perkin-Elmer Paragon 1000 FT/
IR spectrophotometer. FAB mass spectra were measured by
the analytical service of Laboratorium fu¨r Organische Chemie
of the ETH Zu¨rich on a ZAB VSEQ instrument.
X-r a y Str u ctu r es. All X-ray data were collected on a
Siemens SMART platform with CCD detector, normal focus
molybdenum-target X-ray-tube, graphite monochromator, and
ω-scans. Crystal data and refinement details are given in Table
6. Unit cell dimensions determination and data reduction were
performed by standard procedures, and an empirical absorp-
tion correction (SADABS) was applied. The structures was
solved with SHELXS-96 using direct methods and refined by
full-matrix least-squares on F2 with anisotropic displacement
parameters for all non-H atoms except disordered atoms,
[Ru F (d p p p )2]P F 6 (1a ). A CH2Cl2 solution (20 mL) of [RuCl-
(dppp)2]PF6 (817 mg, 0.74 mmol) and TlF (200 mg, 0.90 mmol)
was stirred for 3 h at room temperature. TlCl was filtered off,
and a second portion of TlF (100 mg, 0.45 mmol) was added.
After 2 h the Tl salts were filtered off, PriOH (50 mL) was
added, and CH2Cl2 was removed under vacuum to yield a red
precipitate. The presence of CH2Cl2 (0.5 mol per mol of 1a )
(41) Lespieau, R.; Wakeman, R. L. Bull. Soc. Chim. Fr. 1932, 51,
384.

Toward Metal-Mediated Bond Formation
Organometallics, Vol. 19, No. 15, 2000 2851
Ta ble 6. Cr ysta llogr a p h ic Da ta for Com p lexes 1a , 2a , a n d 3
crystal params
1a
2a
3
empirical formula
fw
cryst syst
space group (no.)
Z
C
56H56Cl4F7P5Ru
C81H72BCl4FOP4Ru
1457.95
monoclinic
P21/c
C117H124Cl6F4P8Ru2
2268.76
triclinic
P1h
1268.80
monoclinic
P21/n
4
4
2
a, Å
b, Å
c, Å
R, deg
â, deg
11.925(2)
14.798(2)
31.644(5)
90
99.59(2)
90
5505.8(14)
1.531
0.686
13.137(2)
34.159(5)
16.989(3)
90
108.03(3)
90
7249.7(19)
1.336
0.500
15.819(2)
15.916(2)
22.580(3)
79.95(3)
71.54(3)
89.87(3)
5301.3(14)
1.421
γ, deg
volume, Å3
F
calc, mg mm-3
µ(Mo KR), mm-1
F(000)
0.613
2344
2604
3008
cryst dimens, mm3
temp, K
0.50 × 0.32 × 0.22
0.40 × 0.20 × 0.14
0.28 × 0.18 × 0.06
213
238
293
Measurement of Intensity Data and Refinement Parameters
radiation (λ, Å3)
2θ range, deg
scan type
Mo KR (0.710 73)
1.31-29.94
1.19-27.71
0.97-26.37
ω
ω
ω
10
40
exposure time, s
detector dist, mm
data collcd
10
40
60
50
-16 e h e 15, 19 e k e15,
-41 e l e 44
38 839
14 217
0.0576, 0.0763
9169
-16 e h e 17, -41 e k e 42,
-22 e l e 21
46 464
15 150
0.0766, 0.1017
9310
-19 e h e 15, -19 e k e 13,
-28 e l e 25
33 385
21 391
0.0541, 0.1330
13 211
no. of data collcd
no. of unique data
R
int, Rσ (%)a
no. of obs data (I >2σ(I))
no. of params
668
1.042
847
1.016
1222
0.977
GOF (F2)
R1(Fo),a wR2(Fo
2
b
)
obs (%)
all (%)
0.0598, 0.1259
0.1097, 0.1473
0.0562, 0.0968
0.1186, 0.1187
0.0610, 0.1300
0.1292, 0.1637
a
b
2
R1(Fo) ) ∑||Fo| - |Fc||/∑|Fo|. wR2(Fo2) ) [∑w(Fo - Fc2)2/∑w(Fo2)2]1/2
.
which were refined isotropically. Hydrogen atoms were intro-
duced at calculated positions on nondisordered C atoms and
refined with the riding model and individual isotropic thermal
parameters. Further details are listed below.
with analytic and 1H NMR data. Positional and thermal
parameters and occupancies of disordered molecules were
refined with constrained C-C (1.54 Å) and C-Cl (1.74 Å) bond
lengths. Max. and min. difference peaks were 1.732 and -0.869
e Å-3; largest and mean ∆/σ were 0.001 and -0.11.
Dark red crystals of 1a were obtained by slow evaporation
of CH2Cl2 from concentrated CH2Cl2/PriOH solutions of the
complex. Analysis of the electron density contour map showed
that the fluoride ligand is disordered between two positions
(F1A and F1B) and that a small amount of chloride (Cl) is
present. Refinement of the occupancy factors f of these three
atoms with the restraints f(F1A) + f(F1B) + f(Cl) ) 1 and
U(F1A) ) U(F1B) gave f(F1A) ) 0.458, f(F1B) ) 0.396, and
f(Cl) ) 0.146. The latter value was confirmed independently
by integration of the 31P NMR spectrum of crystals taken from
the same batch. Positional and thermal parameters, but not
occupancies, were refined in the last cycles. Two CH2Cl2
molecules were found, one of which is disordered. Max. and
min. difference peaks were +0.969 and -0.894 e Å-3; largest
and mean ∆/σ were 2.470 and 0.029. Colorless crystals of
2a BPh4 were obtained by slow evaporation of CH2Cl2 from a
solution of 2a PF6 (5 mg, 5 µmol) and NaBPh4 (20 mg, 0.6
mmol) in CH2Cl2/PriOH (6 mL). Max. and min. difference peaks
were 0.727 and -0.818 e Å-3; largest and mean were ∆/σ )
0.006 and -0.129.
A yellow crystal of 3, obtained by slow evaporation of CH2-
Cl2/hexane solutions, was mounted in a 0.3 mm glass capillary,
which was sealed to prevent loss of solvent of crystallization.
Besides two crystallographically independent [RuF2(dppp)]
molecules, four sites are occupied by cocrystallized solvent: site
1 contains CH2Cl2 (not disordered), sites 2 and 3 contain CH2-
Cl2 or hexane (0.5:0.5 occupancy), and site 4 contains CH2Cl2
(disordered over three positions). The resulting content of the
unit cell is 3‚1.5 CH2Cl2‚0.5 C6H14, in reasonable agreement
Rea ction of 1a w ith R-X. A typical procedure is as
follows. Complex 1a (22 mg, 20 µmol) and the corresponding
substrate 5a -e (20 µmol) were dissolved in CDCl3 (0.4 mL)
in an NMR tube fitted with a Teflon liner and a Young valve.
All manipulations were performed under purified nitrogen in
a glovebox (Braun). The reaction was monitored by 1H, 31P,
and 19F NMR spectroscopy. The identity of the fluorinated
products was determined by 19F NMR spectroscopy by com-
parison with literature data.20,35-38 In the case of reactions with
5a and 5b, integration of the gate-decoupled 19F NMR spec-
trum of the reaction mixture (taking the [PF6]- signal as
reference) indicates quantitative conversion to the fluorinated
product 6. For reactions with 5a (additionally to 19F NMR),
5c, and 5d , the product distribution was determined by
1
1
integration of the H NMR spectrum using an appropriate H
NMR signal of the complexes (δ 7.9-7.7, 4 H, PhH) as internal
standard and is based on (converted) 5a -d .
Relevant features of 1H and 19F NMR spectra of the reaction
solutions are given below. Reaction with 5a : 1H NMR
(CDCl3): δ 5.22 (s, 1 H, CBr-H, 5a ), 6.02 (s, 1 H, CF-H, 6a );
19F NMR (CDCl3): δ -165.4 (d × d × d, 1F, J F,H ) 47.5, 11.7,
1.0 Hz, C-F, 6a ).20 Reaction with 5b: 19F NMR (CDCl3):
-126.1 (lit. -126.2,35 s, 1 F, C-F, 6b). Reaction with 5c: 1H
NMR (CDCl3): δ 6.31 (s, 1 H, CBr-H, 5c, 30%), 6.48 (d, 1 H,
J F,H ) 47.8 Hz, Ph2C(F)-H (6c), 70%), 5.40 (lit. 5.38,39 s, 1 H,
(42) White, E. H.; Reefer, J .; Erickson, R. H.; Dzadzic, P. M. J . Org.
Chem. 1984, 49, 4872.

2852 Organometallics, Vol. 19, No. 15, 2000
Barthazy et al.
Ph2CHOC(H)Ph2, traces). 19F NMR (CDCl3): δ -166.9 (lit.
-169,36 d, 1 F, J F,H ) 46.6 Hz, lit. 48,36 Ph2C(H)-F, 6c).
Reaction with 5d : 1H NMR (CDCl3): δ 1.83 (s, 9 H, C(CH3)3,
5d , 50%), 1.38 (lit. 1.30,38 d, 9 H, J F,H ) 21.1 Hz, lit. 20,38
F-C(CH3)3 (6d ), 10%), 4.66 (lit. 4.55,42 m, 2 H, (CH3)CdCH2,
38%), 1.75 (t, 6 H, J H,H ) 1 Hz, (CH3)CdCH2, 38%), 1.28 (lit.
1.27,40 s, (CH3)3CO(CH3)3, 2%). 19F NMR (CDCl3): δ -131.0
(lit. -132,36 10 lines, 1 F, J F,H ) 21.1 Hz, lit. 21,36 C-F, 6d ).
Ackn owledgm en t. Financial Support from the Swiss
National Science Foundation and the ETH Zu¨rich is
gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Details of X-ray
analyses. This material is available free of charge via the
Internet at http://pubs.acs.org.
OM0000156