P-C Bond Splitting Reactions in Ruthenium(II) Complexes of Binap and MeO-Biphep Using CF3SO3H and HBF4. A Novel Ru-F-H Interaction

Article abstract of DOI:10.1021/om990714m

Reaction of Ru(OAc)₂(1 or 2), 1 = racemic Binap, or 2 = racemic MeO-Biphep, with wet CF₃SO₃H in 1,2-dichloroethane at 363 K results in P-C bond breaking to afford the cationic triflates [Ru(CF₃SO ₃)(6′-diphenylphosphino-1-naphthyl)(PPh₂OH)](CF ₃SO₃), 7a, and [Ru(CF₃SO ₃)(6′-diphenylphosphino-1′-(2-dimethoxy)biphenyI) (PPh₂OH)](CF₃SO₃),7b. Formally, the H⁺ protonates the acetate and water adds across the P-C bond with the resulting arene ring complexed η⁶ to the Ru(II). The solid-state structures of 7a and 7b are reported. A related reaction of Ru(OAc)₂(1 or 2) with HBF₄ gives P-C bond cleavage with the formation of compounds that contain the new phosphinite anion, 6 (C₁₂H₁₁BF₂O₂P), derived from hydrolysis of the BF₄ anion. NMR studies at 213 K on the reaction mixture derived from Ru(OAc)₂(1) and HBF₄ show an HF addition product containing a Ru-F- - -H moiety with ¹J(¹⁹F,¹H) = 66 Hz. Warming of this mixture to 273 K gives P-C bond breaking and isolable complexes, 9, containing the fluorophosphine, Ph₂PF. Complex 10, a Ru-Cl analogue of 9 with complexed Ph₂PF, has also been isolated.

Full text of DOI:10.1021/om990714m

Organometallics 2000, 19, 309-316
309
P -C Bon d Sp littin g Rea ction s in Ru th en iu m (II)
Com p lexes of Bin a p a n d MeO-Bip h ep Usin g CF 3SO3H
a n d HBF 4. A Novel Ru -F -H In ter a ction
Carolien J . den Reijer, Michael Wo¨rle, and Paul S. Pregosin*
Laboratory of Inorganic Chemistry ETH Zentrum, CH-8092 Zu¨rich, Switzerland
Received September 10, 1999
Reaction of Ru(OAc)2(1 or 2), 1 ) racemic Binap, or 2 ) racemic MeO-Biphep, with wet
CF3SO3H in 1,2-dichloroethane at 363 K results in P-C bond breaking to afford the cationic
triflates [Ru(CF3SO3)(6′-diphenylphosphino-1-naphthyl)(PPh2OH)](CF3SO3), 7a , and [Ru-
(CF3SO3)(6′-diphenylphosphino-1′-(2-dimethoxy)biphenyl)(PPh2OH)](CF3SO3), 7b. Formally,
the H+ protonates the acetate and water adds across the P-C bond with the resulting arene
ring complexed η6 to the Ru(II). The solid-state structures of 7a and 7b are reported. A
related reaction of Ru(OAc)2(1 or 2) with HBF4 gives P-C bond cleavage with the formation
of compounds that contain the new phosphinite anion, 6 (C12H11BF2O2P), derived from
-
hydrolysis of the BF4 anion. NMR studies at 213 K on the reaction mixture derived from
Ru(OAc)2(1) and HBF4 show an HF addition product containing a Ru-F- - -H moiety with
1J (19F,1H) ) 66 Hz. Warming of this mixture to 273 K gives P-C bond breaking and isolable
complexes, 9, containing the fluorophosphine, Ph2PF. Complex 10, a Ru-Cl analogue of 9
with complexed Ph2PF, has also been isolated.
In tr od u ction
strate, an unexpected bonding mode is observed6,7 in
which 2 acts as a six-electron donor, e.g., as in the
MeO-Biphep complexes 3 and 4. The complexation of
There are a growing number of reactions involving
chiral Ru(II) complexes. Specifically, Takaya,1 Geneˆt,2
and Schmid3 in olefin hydrogenation, Noyori4 in ketone
reduction, and Ku¨ndig5 in Diels-Alder condensations,
among others, have recently shown that Ru chemistry
is suitable for a number of enantioselective transforma-
tions under relatively mild conditions.
We have been interested6-9 in the Ru chemistry of
the atropisomeric chelating ligands Binap, 1, and MeO-
Biphep, 2. When Ru(OAc)2(2) reacts with 2 equiv of
Bu-phenyl
Bu-phenyl
a double bond from the adjacent arene requires that the
biaryl twist substantially so as to open the arene face
to complexation with a concomitant low-frequency 31P
chemical shift.6,7 The “precoordination” of the arene
together with the strain in the biaryl results in facile
protonation of a P-C bond and η6 arene complexation
(4) Noyori, R.; Hashiguchi, S. Acc. Chem. Res. 1997, 30, 97-102.
Kitamura, M.; Ohkuma, T.; Inoue, S.; Sayo, N.; Kumobayashi, H.;
Akutagawa, S.; Ohta, T.; Noyori, R. J . Am. Chem. Soc. 1988, 110, 629-
631.
Bu-phenyl
(5) Ku¨ndig, E. P.; Saudan, C. M.; Bernadinelli, G. Angew. Chem.
1999, 111, 1298-1301.
(6) Feiken, N.; Pregosin, P. S.; Trabesinger, G. Organometallics
1997, 16, 5756-5762.
HBF4 in the absence of a strongly coordinating sub-
(7) Feiken, N.; Pregosin, P. S.; Trabesinger, G.; Scalone, M. Orga-
nometallics 1997, 16, 537.
(1) Takaya, H.; Ohta, T.; Mashina, K.; Noyori, R. Pure Appl. Chem.
1990, 62, 1135-1138. Noyori, R.; Takaya, H. Acc. Chem. Res. 1990,
23, 345. Takaya, H.; Noyori, R. In Comprehensive Organic Synthesis;
Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, 1991; Vol. 8,
p 443. Kumobayashi, H. Recl. Trav. Chim. Pays-Bas 1996, 115, 201-
210.
(8) Feiken, N.; Pregosin, P. S.; Trabesinger, G. Organometallics
1997, 16, 3735.
(9) den Reijer, C. J .; Ru¨egger, H.; Pregosin, P. S. Organometallics
1998, 17, 5213-5215.
(10) Chan, A. S. C.; Laneman, S. A.; Miller, R. E. In Selectivity in
Catalysis; ACS Symposium Series 517; American Chemical Society:
Washington, DC, 1993; p 27.
(11) Goodson, F. E.; Wallow, T. I.; Novak, B. M. J . Am. Chem. Soc.
1997, 119, 12441-12453.
(12) Morita, D. K.; Stille, J . K.; Norton, J . R. J . Am. Chem. Soc. 1995,
117, 8576-8581. Kong, K. C., Cheng, C. H. J . Am. Chem. Soc. 1991,
113, 6313.
(13) Herrmann, W. A.; Thiel, W. R.; Brossmer, C.; Oefele, K.;
Priermeier, T.; Scherer, W. J . Organomet. Chem. 1994, 461, 51-60.
(2) Geneˆt, J . P. Agros Org. Acta 1995, 1, 4-9. Geneˆt, J . P. Pure Appl.
Chem. 1996, 68, 593-596.
(3) Schmid, R.; Broger, E. A.; Cereghetti, M.; Crameri, Y.; Foricher,
J .; M., L.; Mueller, R. K.; Scalone, M.; Schoettel, G.; Zutter, U. Pure
Appl. Chem. 1996, 68, 131. Schmid, R.; Cereghetti, M.; Heiser, B.;
Scho¨nholzer, P.; Hansen, H. J . Helv. Chim. Acta 1988, 71, 897-929.
Crameri, Y.; Foricher, J .; Hengartner, U.; J enny, C.; Kienzle, F.;
Ramuz, H.; Scalone, M.; Schlageter, M.; Schmid, R.; Wang., S. Chimia
1997, 51, 303.
10.1021/om990714m CCC: $19.00 © 2000 American Chemical Society
Publication on Web 01/14/2000

310 Organometallics, Vol. 19, No. 3, 2000
den Reijer et al.
in the presence of strong acid.9 Adventitious water,
-
together with very slow hydrolysis of the BF4 anion
(over several weeks at 303 K), affords the somewhat
exotic complex 5a .
Bu-phenyl
For 5a , solution and solid-state structures have been
solved.9 Although P-C bond cleavage in metal com-
plexes is known, it is a relatively rare reaction and
normally not induced by protonation.10-13 Formally, 5a
contains the new phosphinite anion, 6 (C12H11BF2O2P).
F igu r e 1. View of the structure of the cation of 7a , 50%
ellipsoids. The oxygen attached to P(1) is clearly visible,
and the η6-complexation is indicated by dotted lines.
from the triflates are ca. 2.16 and 2.18 Å for 7a and 7b,
respectively, and fall at the lower end of the known
range (ca. 2.12-2.30 Å) for this bond.14-19
Our previous observations led us to believe that the
P-C bond splitting was facile and the BF4- hydrolysis
relatively slow (ca. 2 weeks), so that several intermedi-
ates might be detectable. We report here on an exten-
sion to Binap, a new and faster variation of this P-C
cleavage reaction, and structural studies pertinent to
the reaction mechanisms.
The Ru-P separations are also routine; however, the
six Ru-C arene bond lengths in both 7a and 7b are very
different and seem to exist in three groups of two. Two
distances are relatively short, Ru-C1 and Ru-C6, ca.
2.13-2.16 Å, but fairly normal;20-23 two are slightly
long, Ru-C4 and Ru-C5, 2.29-2.32 Å; and two are
quite long, Ru-C2 and Ru-C3, ca. 2.35-2.48 Å. Inspec-
tion of the X-ray literature for arene complexes of Ru-
(II) suggests that routine Ru-C separations in a variety
of substituted and simple Ru-arene complexes should
be on the order of 2.15-2.28 Å with the average at ca.
2.23 Å.24 Specifically, the observed values at 2.480(5)
and 2.477(5) Å for C2 and C3 in 7a suggest a weak
interaction. These differences might be related to steric
effects, in that the longer distances involve the two
sterically hindered fully substituted arene carbons.
Further, in 7a we find modest intramolecular 13C
coordination chemical shifts, ∆δ, 14.9 and 24.6 ppm, for
the complexed arene carbons C2 and C3, relative to the
41.4 and 62.7 ppm values of ∆δ found for C1 and C6
Resu lts a n d Discu ssion
1. Ru -Tr ifla te Ch em istr y. The synthesis of the
arene complex 5a was complicated due to the slow, but
-
-
concurrent BF4 anion hydrolysis. To avoid this BF4
complication, Ru(OAc)2(1 or 2) (1 ) racemic Binap, 2 )
racemic MeO-Biphep) was allowed to react with slightly
more than 2 equiv of wet CF3SO3H in 1,2-dichloroethane
at 363 K. These conditions gave the products 7a ,b in a
few hours in good yield (see Scheme 1 and Experimental
Section). Formally, the H+ protonates the acetate and
(14) Svetlanova-Larsen, A.; Zoch, C. R.; Hubbard, J . L. Organome-
tallics 1996, 15, 3076-3087.
(15) Mauthner, K.; Slugovc, C.; Mereiter, K.; Schmid, R.; Kirchner,
K. Organometallics 1997, 16, 1956-1961.
(16) Fong, T. P.; Lough, A. J .; Morris, R. H.; Mezzetti, A.; Rocchini,
E.; Rigo, P. J . Chem. Soc., Dalton Trans. 1998, 2111-2113.
(17) Burns, R. M.; Hubbard, J . L. J . Am. Chem. Soc. 1994, 116,
9514-9520.
the water adds across the P-C bond.
(18) Blosser, P. W.; Gallucci, J . C.; Wojcicki, A. Inorg. Chem. 1992,
31, 2376-2384.
2. Solid -Sta te Str u ctu r es. The structures of 7a ,b
were determined by X-ray diffraction, and views of the
cations are shown in Figures 1 and 2. The immediate
coordination spheres both contain an η6 -arene, one
oxygen of the triflate anion, and two phosphorus do-
nors: one from the new monodentate P(OH)Ph2 ligand
and the second from the P(biaryl)Ph2 ligand. The oxygen
atoms attached to the P1 donors are clearly visible.
Table 1 shows a list of selected bond lengths and bond
angles for these complexes. The Ru-O bond lengths
(19) Abbenhuis, R. A. T. M.; del Rio, I.; Bergshoef, M.; Boersma, J .;
Veldman, N.; Spek, A. L.; van Koten, G. Inorg. Chem. 1998, 37, 1749-
1758.
(20) Yamamoto, Y.; Sato, R.; Matsuo, F.; Sudoh, C.; Igoshi, T. Inorg.
Chem. 1996, 35, 2329-2336.
(21) Brunner, H.; Oeschey, R.; Nuber, B. Organometallics 1996, 15,
3616-3624.
(22) Bhambri, S.; Tocher, D. A. Polyhedron 1996, 15, 2763-2770.
(23) Roethlisberger, M. S.; Salzer, A.; Buergi, H. B.; Ludi, A.
Organometallics 1986, 5, 298-302.
(24) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, R. J . Chem. Soc., Dalton Trans. 1989, S1-S83.

P-C Bond Splitting Reactions in Ru(II) Complexes
Organometallics, Vol. 19, No. 3, 2000 311
Sch em e 1. P r ep a r a tion of th e Hyd r oxyp h osp h in e-Ar en e Tr ifla tes, 7a a n d 7b
Ta ble 1. Selected Bon d Len gth s (Å) a n d Bon d
An gles (d eg) for th e Ca tion s in 7a a n d 7b
Ta ble 2. 13C Coor d in a tion Ch em ica l Sh ifts, ∆δ, for
7a a n d 7b
7a
7b
Ru-P(1)
Ru-P(2)
Ru-O (OTf)
Ru-C(1)
Ru-C(6)
Ru-C(4)
Ru-C(5)
Ru-C(2)
Ru-C(3)
P(1)-OH
2.2865(14)
2.3389(14)
2.155(4)
2.135(5)
2.161(5)
2.321(5)
2.300(5)
2.480(5)
2.477(5)
1.591(4)
2.3105(16)
2.3529(16)
2.178(4)
2.136(5)
2.153(6)
2.306(6)
2.290(6)
2.408(6)
2.347(6)
1.583(4)
P(1)-Ru-P(2)
P(1)-Ru-O(2)
P(2)-Ru-O(2)
91.76(5)
94.64(11)
94.73(11)
89.59(6)
93.31(12)
96.87(13)
13C
position
∆δ 13C
7a
∆δ 13C
7b
13C
position
∆δ 13C
7a
∆δ 13C
7b
1′-1
6′-6
4′-4
41.4
62.7
32.0
33.3
64.4
34.2
5′-5
2′-2
3′-3
20.3
14.9
24.6
22.9
12.2
33.6
-mode, but has simply slipped across the face of the
arene. However, it is also likely that P2, the phosphorus
donor that was not involved in the P-C cleavage, serves
as a tether which does not permit the Ru atom to move
freely across the face of the hydrocarbon. For 7a it is
probably correct to consider the arene bonding as closer
to η4 than to η6. We do not find evidence for an
intramolecular H-bond between the P(OH) and an
oxygen of the complexed triflate; however, in 7b, one
finds a short 1.8 Å separation between the assigned
position of the hydroxyl-H and an oxygen of the uncom-
plexed triflate.
3. NMR Stu d ies on th e Tr ifla tes. The solution
structures for 7a ,b were confirmed by multinuclear,
multidimensional NMR spectroscopy.25,26 Their 31P spec-
tra show the expected AX pattern, with the complexed
Ph2POH ligand appearing at higher frequency (δ )
114.5 in 7a and 104.1 in 7b). Their 13C spectra show
six, and their 1H spectra, three (7a ) or four (7b)
resonances, respectively, from the coordinated ring, all
strongly shifted to lower frequencies, due to the complex-
ation.23,27-29 The complexed arene protons were con-
nected to their corresponding 13C signals via a 2-D
F igu r e 2. View of the structure of the cation of 7b, 50%
ellipsoids. The oxygen attached to P(1) is clearly visible,
and the η6-complexation is indicated by dotted lines.
(see Table 2). These data support a weak interaction
between Ru and C2 and C3.
We find it interesting that Ru-C1 and Ru-C6 are
relatively short, as these were the two arene carbons
involved in the η2 olefin bonding shown in, for example,
3 and 4. This suggests that the metal does not release
C1 or C6 during the change from the η2-mode to the η6
(25) Pregosin, P. S.; Salzmann, R. Coord. Chem. Rev. 1996, 155, 35-
68.
(26) Pregosin, P. S.; Trabesinger, G. J . Chem. Soc., Dalton Trans.
1998, 727-734.
(27) Mann, B. E.; Taylor, B. F. 13C NMR Data for Organometallic
Compounds; Academic Press: London, 1981; p 254.

312 Organometallics, Vol. 19, No. 3, 2000
den Reijer et al.
Ta ble 3. NMR Da ta for th e Com p lexes 7a a n d 7ba
7a
7b
position
δ
31P
δ
19F
-78.2
δ
31P
δ
19F e
1
2
114.5
53.4
104.1
50.2
-77.8
-79.3
-79.5
δ 1Hb,c,f
δ
13C
δ 1Hd,f
δ
13C
1
2
3
4
5
6
7
8
9
10
1′
2′
3′
4′
5′
6′
7′
8′
9′
10′
OH
99.6
93.7
146.4
81.4
97.6
102.7
79.5
56.9
116.9
110.6
100.0
107.6
77.9
5.98
6.63
5.22
5.67
2.99
F igu r e 3. 13C-1H correlation for 7b showing cross-peaks
7.54
5.54
5.84
6.34
6.94
7.78
8.03
1
for the four 13C and H resonances of the complexed ring.
The chemical shifts appear at relatively low frequency,
indicative of complexation (400 MHz, CD2Cl2, ambient
temperature). The one-bond coupling is retained in the
proton direction.
127.4
135.4
134.8
131.8
141.0
131.7
135.2
132.0
127.9
140.7
129.1
129.2
127.7
129.1
127.8
158.7
115.0
131.8
125.6
143.9
56.4
7.25
7.68
7.15
8.30
7.81
7.81
7.68
7.82
8.20
10.02
3.94
9.66
a
b
400 MHz, CD2Cl2. Exchange between OH and water. c Cor-
d
relation between P1 and OH. Exchange between OH and water.
e No or slow exchange between OTf groups. f 7a : H4, 7.54,
3J (H,H))7.3, 3J (P,H) ) 2.1; H5, 5.54, 3J (H,H) ) 7.3 and 5.3,
3J (P,H) ) 2.3; H6, 5.84, J (H,H) ) 5.3, 3J (P,H) ) 4.3. 7b: H3, 5.98,
J (H,H) ) 7.0, 0.7, 3J (P,H) ) 1.5; H4, 6.63, J (H,H) ) 7.0, 6.6, and
3
3
1.4, J (P,H) ) 2.1; H5, 5.22, J (H,H) ) 6.6, 5.2, and 0.7, J (P,H) )
2.1; H6, 5.67, J (H,H) 5.2 and 1.4, 3J (P,H) ) 3.7.
(19F, 1H) shows a close contact between the uncomplexed
OTf and the OH-proton. The 19F spectrum reveals two
separate triflate absorptions for each complex. Table 3
shows a selection of 1H, 13C, 19F, and 31P NMR data for
7a ,b.
The observation of a single diasteromer in the NMR
spectra of 7a and 7b is thought to be due to kinetic
control of the P-C bond splitting. Starting from, for
example, racemic MeO-Biphep, the new phosphorus
ligand moves from the position indicated by the arrows
to the stereogenic Ru atom such that either the R,R or
S,S diasteromer is formed. Solution NMR measure-
F igu r e 4. Section of the 31P-1H correlation belonging to
compound 7a . The correlation to the OH proton (Ha) is
clear, as is the two strong sets of cross-peaks due to the
two sets of ortho P-phenyl protons. There are weak cor-
relations to the meta protons and one of the protons of the
complexed ring (400 MHz, CD2Cl2, ambient temperature).
13C,1H correlation, and a section of this is shown in
Figure 3 for 7b.
The OH proton is observed at δ ) 10.02 and 9.66,
respectively and for 7a can be correlated to its 31P
signal; see Figure 4. The high-frequency position of the
P(OH)-proton combined with its observed relatively slow
exchange with water in the solvent (based on 2-D
exchange spectroscopy) suggests that the OH may be
hydrogen bonded (perhaps to an uncomplexed, anionic
triflate oxygen atom, vida supra). A HOESY experiment
ments show that these complexes do not epimerize
rapidly on the NMR time scale at ambient temperature.
4. Ru -BF 4 Ch em istr y. Since the use 1,2-dichloro-
ethane at 363 K in the synthesis of 7a ,b reduced the
(28) Bennett, M. A.; McMahon, I. J .; Pelling, S.; Brookhart, M.;
Lincoln, D. M. Organometallics 1992, 11 127.
(29) Faller, J . W.; Chase, K. J . Organometallics 1995, 14, 1592-
1600.

P-C Bond Splitting Reactions in Ru(II) Complexes
Organometallics, Vol. 19, No. 3, 2000 313
at relatively low frequency, δ ) 0.66, due to the
anisotropy of a proximate P-phenyl ring; however, its
13C chemical shift is routine, δ ) 20.2 (δ 13CO ) 166.1).
Models suggest that if the acetate was bound in a
bidentate mode, the methyl position would be incorrect
1
for the observed H chemical shift. However, H-bonding
of the acetate oxygen to the hydrogen of the HF places
the methyl group correctly. These NMR data for 8 are
summarized below:
F igu r e 5. 19F and 31P spectra for 5b. Top: BF2 region
showing two sets of 19F resonances for each of the non-
equivalent F atoms of the BF2. Bottom: The nonequivalent
31P resonances. When expanded, one can see the second
set of 31P signals here as well (400 MHz, CD2Cl2, ambient
temperature).
reaction time without destroying the arene bonding, we
allowed both Ru(OAc)2(1) and Ru(OAc)2(2) to each react
with 2.1 equiv of HBF4 (Et2O) in this solvent at 363 K.
Indeed, both 5a ,b could be obtained in a few days rather
than weeks9 (see Experimental Section). Compound 5b
was not part of our earlier report,9 and it has been
characterized via 1H, 11B, 13C, 19F, and 31P NMR in
conjunction with 2-D spectroscopy. Figure 5 shows 19F
and 31P resonances for (in this case) the two diastere-
omers of 5b. The slow kinetics combined with relatively
large and awkward ligand 6 are thought to be respon-
sible for the epimerization; that is, there is sufficient
time for ligand dissociation which leads to epimeriza-
tion.
We cannot exclude the possibility that water is involved
in the H-bond network and/or that it functions as a sixth
ligand.
There are very few HF complexes,34 although some
M(HF2) derivatives are known.35 In these literature
complexes one often finds relatively large values of
1J (19F,1H), ca. 400 Hz.34 Consequently, given our value
of 66 Hz, the H-F bond in 8 is weak, and we consider
8 as a stabilized Ru-F complex. In the compound RuH-
(HF2)(dmpe), reported by Perutz and co-workers,36 one
As the BF4- hydrolyzes slowly, we measured a set of
NMR spectra after mixing cooled solutions of Ru(OAc)2-
(Binap) with 2.2 equiv of HBF4 in CD2Cl2 at 213 K, with
the goal of identifying intermediates in the P-C bond
splitting reaction. We observe several species present
in solution; however, the major component (ca. 8 times
greater than the others) can be assigned to 8, a structure
1
observes two different J (19F,1H) values, one large, 274
Hz for the strong H-F interaction, and a much smaller
one, <30 Hz, for the M-F moiety.37
Warming the solution containing 8 to 273 K affords
the fluorophosphine complex 9. Formally, the proton of
the HF (or one from proximate water) cleaves the P-C
bond while forming the new P-F bond. The fluorophos-
phine complexes 9 exist as a mixture of two components,
9a and 9b in the ratio ca. 7:3, and show the character-
1
istic very large J (31P,19F) values,38 ca. 948 Hz (and 956
Hz), as well as 2J (31P,31P) values, 54 Hz (and 52 Hz).
1
The η6-arene bonding is supported by the H and 13C
data which reveal the expected low-frequency shifts (see
Table 4). We know of only one other example in which
a P-C bond is broken and a P-F bond made, and this
in which the Binap functions as a six-electron donor,6,7,30
on the basis of the observed very low frequency 31P
chemical shift, δ ) 6.3 of the 31P spin adjacent to the
complexed olefin.6,7,30 This represents yet another (albeit
rare) example of the complexation of the adjacent biaryl
double bond. The second phosphorus signal appears at
(32) We are not certain of the source of this selectivity. It might
arise from the well-known geometric dependence of 2J (31P,X), X ) 1H,
13C, 31P, ..., etc., with trans . cis. If the structure were indeed five-
coordinate, the high-frequency 31P spin would occupy a pseudo-trans
position relative to the 19F spin. Since both the 19F and 31P lines are
broad, couplings of <5 Hz would not be observed.
(33) We also find a very weak proton signal at δ ) 9.92, as a doublet
with 1J (19F,1H) ) 267 Hz, as well as a broad singlet at δ ) 13.09. These
are assigned to solvated HF (a slight excess of HBF4, 2.2 equiv, is
present) and HOAc, respectively. The 267 Hz value is similar to that
found by Whittlesey et al.36
2
its normal position, δ ) 80.6, J (31P,31P) ) 45 Hz. The
-
BF4 anion has been cleaved to afford a Ru-F- -H
interaction plus Et2O-BF3 (whose identity has been
confirmed via comparison with an independent sample31).
Complex 8 shows a 19F signal at δ ) 18.3, with a
coupling to the proton of 66 Hz and a second spin-spin
coupling to only one of the two 31P signals, 157 Hz.32
There is a 1H signal33 at δ ) 11.20, with 1J (19F,1H) )
66 Hz. The complexed acetate methyl signal is found
(34) Lee, D. H.; Kwon, H. J .; Patel, B. P.; Liable-Sands, L. M.;
Rheingold, A. L.; Crabtree, R. H. Organometallics 1999, 18, 1615-
1621. Majez, Z.; Borrmann, H.; Lutar, K.; Zemva, B. Inorg. Chem. 1998,
37, 5912.
(35) Murphy, V. J .; Hascall, T.; Chen, J . Y.; Parkin, G. J . Am. Chem.
Soc. 1996, 118, 7428-7429.
(36) Whittlesey, M. K.; Perutz, R. N.; Greener, B.; Moore, M. H.
Chem. Commun. 1997, 187-188.
(30) Pathak, D. D.; Adams, H.; Bailey, N. A.; King, P. J .; White, C.
J . Organomet. Chem. 1994, 479, 237.
(31) Observed for an independent sample of Et2O-BF3 ) 4.23 (q,
2H) and 1.38 (t, 3H). In-situ measurements on 8 show 4.23 (q, 2H)
and 1.40 (t, 3H), both under the same conditions (CD2Cl2, 400 MHz,
213 K).
(37) In the RuH(HF2)(Ph2PCH2CH2PPh2) analogue, the values are
392 and 36 Hz, respectively. Perutz, R. Personal communication,
Nottingham, J uly, 1999.
(38) Verkade, J . G.; Mosbo, J . A. In Stereospecificity in 1J Coupling
to Metals; Verkade, J . G., Mosbo, J . A., Eds.; VCH: Deerfield Beach,
FL, 1987; Vol. 8, pp 425-463.

314 Organometallics, Vol. 19, No. 3, 2000
den Reijer et al.
Ta ble 4. 1H, 13C, 19F , a n d 31P NMR Da ta for 9 a n d
10a
F igu r e 6. 19F and 31P for 10. Top: 19F showing the large
1J (3P,19F) for the complexed Ph2P-F ligand. Bottom: 31P
showing both 1J (31P,19F) and 2J (31P,31P) (400 MHz, CD2-
Cl2, ambient temperature).
9a b,e
10d
position
position
δ
31P
δ
19F
-121.7
δ
31P
δ
19F
-122.5
1
2
181.8
51.5
δ 1H
5.69
6.07
6.56
1
2
176.7
53.5
Con clu sion s
13C
δ 1H
δ
13C
The results described above clearly show that, in the
absence of suitable ligands, acid-promoted P-C bond
cleavage and arene complexation can be facile in Ru
complexes of both 1 and 2. In the presence of triflic acid
plus water, complexed diphenyl hydroxyphosphine is
produced. With HBF4 as acid, complexed diphenyl
fluorophosphine is the product. Examples of both of
these structural types have been isolated and character-
ized. In the HBF4 chemistry with Binap, a novel Ru-
F- - -H intermediate was detected at 213 K in which the
Binap acts as a six-electron donor, using both phospho-
rus atoms and one double bond of the adjacent biaryl
ring. The appearance of 5a ,b, containing the exotic
monodentate 6, after long reaction times can now be
rationalized in terms of slow hydrolysis of the P-F and
B-F bonds. The new isolable arene complexes, 7a ,b
(with PPh2OH) and 10 (with Ph2PF), are readily avail-
able and offer access to a wide variety of new organo-
ruthenium derivatives with phosphinoarene chelates.
δ
4
5
6
106.3
77.7
1
2
3
4
5
6
7
8
9
10
2′
3′
4′
5′
6′
7′
8′
9Å
10Å
109.0
113.2
113.0
108.7
81.8
101.8
5.95
5.97
6.93
7.92
7.98
7.16
6.57
101.4
129.3
136.4
132.1
128.7
131.5
135.0
132.1
128.0
144.2
129.0
130.0
129.6
125.5
9bc,e
δ
31P
δ
19F
-115.5
1
2
183.6
41.4
δ 1H
5.60
5.82
6.55
δ
13C
4
5
6
108.8
78.4
8.24
7.61
103.8
7.94
7.84
7.73
8.20
a
b
400 MHz, CD2Cl2 Major isomer, 213 K, assigment based on
the observations for 10. c Minor isomer, 213 K, assigment based
on the observations for 10. Ambient temperature. e 9a : H4, 5.69,
d
3J (H,H) ) 5.3, 3J (P,H) ) 4.2; H5, 6.07, 3J (H,H) ) 7.2 and 5.3,
3J (P,H) ) 2.7; H6, 6.56, 3J (H,H) ) 7.2. 9b: H4, 5.60, 3J (H,H) )
5.2, 3J (P,H) ) 4.2; H5, 5.82, 3J (H,H) ) 7.3 and 5.2, 3J (P,H) ) 2.3;
H6, 6.55 br d, 7.3.
Exp er im en ta l Section
All manipulations were carried out under an argon atmo-
sphere. Diethyl ether was distilled from sodium benzophenone
ketyl, 1,2-dichloroethane from P4O10, dichloromethane from
CaH2, and hexane from sodium. All the other chemicals were
commercial products and were used as received. rac-2,2′-Bis-
(diphenylphosphino)-1,1′-binaphthyl (Binap) was purchased
from Strem Chemicals. (R,S)-(6,6′-Dimethoxybiphenyl-2,2′-
diyl)bis(diphenylphosphine oxide) was a gift from F. Hoffmann-
La Roche AG, Basel. The reduction of this diphosphine oxide
by reported methods40 (1) gave the ligand (R,S)-(6,6′-
dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine) (MeO-Bi-
phep).
concerns cleavage in a Ir(Me)(PEt3)3 complex using C6F6
to form a FPEt2 donor.39
X-r a y. Crystals of 7a and 7b were mounted on glass
capillaries, and data sets covering a hemisphere were collected
on a Siemens SMART platform diffractometer equipped with
a CCD detector (ω-scans with 0.3° step width). Data reduction
plus corrections for Lorentz polarization and absorption was
performed using the programs SAINT41 and SADABS.42 The
structures were solved by direct methods and refined by full-
matrix least-squares (versus F2) with the SHELXTL program
package.43 All non-hydrogen atoms except the atoms belonging
to disordered groups or solvent molecules were refined with
anisotropic thermal parameters, but hydrogen atoms at cal-
culated positions were refined with common isotropic thermal
parameters for each group.
Reaction of 9 with an excess of LiCl afforded the
chlorofluorophosphine complex 10 as a single product,
in which only the oxygen donor ligand has been substi-
tuted. This observation supports the idea that only one
diastereomer is formed if the reaction proceeds quickly.
Chloro compound 10 could be isolated in 74% yield and
its structure proof followed in analogy to 9. Figure 6
shows the 19F and 31P resonances for 10 with their
characteristic large one-bond spin-spin interactions. A
summary of this HF/BF4 chemistry is given in Scheme
2, and further details are given in the Experimental
Section.
(40) Schmid, R.; Foricher, J .; Cereghetti, M.; Schoenholzer, P. Helv.
Chim. Acta 1991, 74, 370.
(41) SAINT, Version 4; Siemens Analytical X-ray Systems, Inc.:
Madison, WI.
(42) Sheldrick, G. SADABS; Go¨ttingen, 1997.
(43) SHELXTL program package, Version 5.1; Bruker AXS, Inc.:
Madison, WI.
(39) Blum, O.; Frolow, F.; Milstein, D. Chem. Commun. 1991, 258.

P-C Bond Splitting Reactions in Ru(II) Complexes
Organometallics, Vol. 19, No. 3, 2000 315
Sch em e 2. Ch em istr y of Ru (OAc)2(Bin a p ) w ith HBF 4
In 7a , all the triflate anions, one phenyl group, and a not
further specified solvent molecule showed a considerably
strong positional disorder. Wherever possible, a split model
was applied. The solvent molecule was described with partially
occupied C atom positions with a common isotropic displace-
ment parameter. In 7a there are electron density peaks (C1L
to C3L) located in a large void of the structure which could
not be interpreted in terms of a clearly identified solvent.
Nevertheless these peaks were included in the refinement; the
effect of neglecting them on the R-value is relatively small
(improvement of R1 of about 0.4%).
In 7b one triflate anion is strongly disordered and conse-
quently was described by two partially occupied anion posi-
tions. The occupation factors refined to values of 0.533(4) and
0.467(4), respectively. The same geometric constraints were
applied for both possible anion positions, and a common
isotropic displacement parameter was used for the affected
atoms. The somewhat larger R-values are certainly acceptable
considering that there is now a model for the observerd
disorder available. Crystallographic data and details of the
structure determinations are given in Table 5.
Syn th esis of [ Ru (C12H10BF 2O2P )(6′-d ip h en ylp h os-
p h in o-1-n a p h th yl)(BF 4), 5b. Ru(OAc)2(1) (40.0 mg, 0.05
mmol) was dissolved in 2 mL of 1,2-dichloroethane. This was
followed by addition of 2.3 equiv of tetrafluoroboric acid (15
µL, 7.3 M in Et2O). After ca. 48 h at 363 K the resulting
mixture was filtered using a glass filter and the 1,2-dichloro-
ethane distilled under high vacuum. The crude reaction
mixture was washed three times with 1 mL of hexane. The
product was recrystallized from a dichloromethane-ether
mixture to afford 36.8 mg (87%) of yellow 5b. Anal. Calcd for
P2, 52); 19F, -140.4 (d, F1A, 62), -146.5 (d, F1A′, 62), -140.5
(d, F1B, 62), -146.6 (d, F1B′, 62), -150.8 (25%, F2), -150.8
(75%, F2); 13C, 142.3 (d, C6′, 53), 141.5 (d, C3′, 22), 136.3 (s,
C9), 134.8 (s, C1′), 134.8 (s, C8), 131.7 (d, C4′, 7), 131.4 (d,
C2′, 3), 130.3 (s, C10), 129.9 (s, C8′), 129.1 (s, C10′), 128.4 (s,
C9′), 128.4 (s, C5′), 127.7 (s, C7), 125.4 (s, C7′), 113.6 (d, C2,
9), 110.0 (d, C3, 6), 105.7 (d, C5, 6), 102.7 (d, C1, 4), 95.1 (d,
1
C4, 9), 73.3 (s, C6); H, 8.43 (d, H10, 8.3), 8.24 (dd, H4′, 8.8,
2.0), 8.20 (d, H10′, 8.7), 7.95 (d, H7′, 8.2), 7.92 (t, H9, 8.2, 7.8),
7.84 (ddd, H8′, 8.3, 6.9, 1.2), 7.77 (dd, H5′, 8.9, 6.9), 7.71 (ddd,
H8′, 8.3, 6.9,1.2), 7.30 (br d, H4, 7.0, 2.1), 6.95 (H8, 8.6, 7.8),
6.26 (br d, H7, 8.6), 5.93 (br, Ha), 5.85 (dd, H6, 4.7, 2.7), 5.15
(ddd, H5, 7.0, 4.7, 2.3).
Syn th esis of of [Ru (CF 3SO3)(6′-d ip h en ylp h osp h in o-1-
n a p h th yl)(P P h 2OH)](CF 3SO3), 7a . Ru(OAc)2(1) (65.0 mg,
0.08 mmol) was dissolved in 2 mL of 1,2-dichloroethane and
then treated with 2.4 equiv of trifluoromethanesulfonic acid
(16 µL, 0.18 mmol). The solution color turned immediately from
yellow to orange. After heating for 1 h at 363 K, the solution
was filtered using a glass filter. The 1,2-dichloroethane was
evaporated under high vacuum. The crude reaction mixture
was stirred and washed three times with 1 mL of ether, and
the complex was then recrystallized from dichloromethane-
ether. A suitable crystal for X-ray diffraction was obtained
from the same mixture of solvents. Color: orange. Yield: 59.6
mg (74%). Anal. Calcd for C46H34O7F6P2S2Ru (1039.94): C,
53.13; H, 3.30. Found: C, 53.01; H, 3.44. FAB-MS: calcd 890.9;
found 891.1.
Syn th esis of [Ru (CF 3SO3)(6′-d ip h en ylp h osp h in o-1′-(2-
d im eth oxy)bip h en yl)(P P h 2OH)](CF 3SO3), 7b. Ru(OAc)2(2)
(60.8 mg, 0.08 mmol) was dissolved in 2 mL of 1,2-dichloro-
ethane and 2.1 equiv of trifluoromethanesulfonic acid (14 µL,
0.16 mmol) added. The solution color turned immediately from
yellow to orange. After heating for 1 h at 363 K, the reaction
C
44H34O2B2F6P2Ru (893.38): C, 59.16; H, 3.84. Found: C,
59.07; H, 3.90. FAB-MS: calcd M+ 805.6; found 805.8. NMR
(400 MHz, J in Hz, CD2Cl2, rt): 31P, 116.6 (d, P1, 52), 50.1 (d,

316 Organometallics, Vol. 19, No. 3, 2000
Ta ble 5. Cr ysta l Da ta a n d Str u ctu r e Refin em en t for 7a a n d 7b
den Reijer et al.
7a
7b
formula
C46.73 H34 F6 O7 P2 Ru S2
C40 H34 F6 O9 P2 Ru S2
formula weight
temperature, K
radiation
1049.83
293(2)
999.80
293(2)
Mo KR (graphite-monochromated, λ ) 0.71073 Å)
cryst syst
triclinic
P-1
monoclinic
P21/c
space group
unit cell dimens
a, Å
15.099(2)
21.020(3)
b, Å
16.131(2)
10.294(2)
c, Å
19.817(3)
21.626(3)
R, deg
108.20(3)
103.14(3)
94.34(3)
4408.7(12)
90
â, deg
117.16(3)
90
4163.4(11)
4
γ, deg
volume, Å3
Z
4
density (calcd), Mg/m3
abs coeff
1.580
1.595
0.601 mm-1
2122
0.635 mm-1
2024
F(000)
cryst size, mm3
θ-range for data collection, deg
index ranges
0.50 × 0.18 × 0.08
0.36 × 0.32 × 0.22
1.89-26.40
-25 e h e 26, -8 e k e 12,
-27 e l e 27
25 182
1.12-24.74
-17 e h e 17, -18 e k e 18,
-23 e l e 23
24 430
no. of reflns colld
no. of ind reflns
14 887 [Rint ) 0.0486]
8492 [Rint ) 0.0545]
completeness to θ, deg, %
max. and min. transmission
no. of data/restraints/params
GOOF on F2
24.74, 98.9
26.40, 99.6
0.9535 and 0.7533
14 887/0/1156
0.976
0.8730 and 0.8037
8492/38/522
1.040
final R indices [I > 2σ(I)]
R1 ) 0.0500, wR2 ) 0.1221
R1 ) 0.0885, wR2 ) 0.1457
1.065 and -0.813
R1 ) 0.0695, wR2 ) 0.1793
R1 ) 0.1071, wR2 ) 0.2061
2.037 and -1.315
R indices (all data)
largest diff peak and hole, e Å-3
mixture was filtered using a glass filter. The 1,2-dichloro-
ethane was evaporated under high vacuum. The crude reaction
mixture was stirred and washed three times with 1 mL of
ether. The complex was recrystallized from dichloromethane-
ether. A suitable crystal for X-ray diffraction was obtained
from the same mixture of solvents. Color: orange. Yield: 59.2
mg (78%). Anal. Calcd for C40H34O9F6P2S2Ru (999.84): C,
48.05; H, 3.43. Found: C, 48.00; H, 3.56. FAB-MS: calcd M+-
OTf 701.7; found 701.3.
P r ep a r a tion a n d /or Isola tion of Com p ou n d s 8, 9, a n d
10. Ru(OAc)2(1) (41.1 mg, 0.05 mmol) was dissolved in 2 mL
of CD2Cl2. The solution was cooled to ca. 195 K before 2.2 equiv
of tetrafluoroboric acid (15 µL, 7.3 M in Et2O) was added. The
reaction was then immediately monitored by NMR at 213 K.
After 30 min, intermediate 8 was observed as the main
product. The mixture was then warmed to 273 K for 1.5 h to
afford intermediate 9. The reaction mixture was then cooled
to 213 K (to stabilize this intermediate), and 9 was character-
ized via NMR methods. At 213 K, 23.6 mg (0.56 mmol) of LiCl
was added to the yellow reaction mixture. The mixture became
immediately red in color. After stirring overnight the reaction
mixture was filtered through Celite. The solvent was evapo-
rated in vacuo and the product recrystallized from dichlo-
romethane-ether to afford 32.3 mg (74%) of a red solid. Anal.
Calcd for C44H34O2B2F6P2Ru‚H2O (893.38): C, 59.78; H, 3.99.
Found: C, 59.76; H, 4.02. FAB-MS: calcd M+, 780.26; found,
780.89.
Ack n ow led gm en t. P.S.P. thanks the Swiss Na-
tional Science Foundation and the ETH, for financial
support. We also thank J ohnson Matthey for the loan
of metal salts and F. Hoffmann La-Roche, Basel, for the
gift of MeO-Biphep ligands.
Su p p or tin g In for m a tion Ava ila ble: Complete number-
ing scheme for the ORTEP diagrams. Table with experimental
parameters (Table S1). Atomic coordinates and equivalent
isotropic temperature factors (Table S2). Extended list of bond
lengths and bond angles (Table S3). Anisotropic displacement
parameters (Table S4). Calculated hydrogen coordinates and
isotropic displacement parameters (Table S5). This material
is available free of charge via the Internet at http://pubs.acs.org.
OM990714M