Synthesis and structures of organometallic aqua complexes of ruthenium(II)

Article abstract of DOI:10.1021/om990411s

Treatment of all-cis-Ru(dppe)(CO)₂Cl₂ (dppe = Ph₂PCH₂CH₂PPh₂) with 2 equiv of AgOSO₂-CF₃ yields the bis(triflate) complex Ru(dppe)(CO)₂(OSO₂CF₃)₂ (1), which has been characterized by NMR spectroscopy and X-ray crystallography. Exposure of solid 1 to atmospheric moisture gives the carbonyl aqua complex Ru(dppe)(CO)(H₂O)(OSO₂CF₃)₂ (2). The X-ray structure of 2 shows both intra- and intermolecular hydrogen bonding between the coordinated water and triflates. The ¹⁹F NMR spectra of 1 and 2 display coupling between the triflate groups; ¹⁹F-¹⁹F NOESY suggests that this arises from both through-bond and through-space coupling. The reaction of 1 with 10 equiv of water results in the rapid formation of a species assigned as the cationic diaqua complex [Ru(dppe)(CO)(H₂O)₂(OSO₂CF ₃)][OSO₂-CF₃] (3). Over a longer period of time, further reaction occurs to form the triaqua carbonyl complex [Ru(dppe)(CO)(H₂O)₃][OSO₂CF₃] ₂ (4), which has also been characterized by X-ray crystallography. The structure of 4 indicates that all three water ligands participate in hydrogen bonding. Complex 4 is unstable in the absence of water, re-forming a mixture of 1 and 2.

Full text of DOI:10.1021/om990411s

4068
Organometallics 1999, 18, 4068-4074
Syn th esis a n d Str u ctu r es of Or ga n om eta llic Aqu a
Com p lexes of Ru th en iu m (II)
Mary F. Mahon,† Michael K. Whittlesey,*,† and Paul T. Wood‡
Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K., and
School of Chemical Sciences, University of East Anglia, Norwich NR4 7TJ , U.K.
Received J une 1, 1999
Treatment of all-cis-Ru(dppe)(CO)2Cl2 (dppe ) Ph2PCH2CH2PPh2) with 2 equiv of AgOSO2-
CF3 yields the bis(triflate) complex Ru(dppe)(CO)2(OSO2CF3)2 (1), which has been character-
ized by NMR spectroscopy and X-ray crystallography. Exposure of solid 1 to atmospheric
moisture gives the carbonyl aqua complex Ru(dppe)(CO)(H2O)(OSO2CF3)2 (2). The X-ray
structure of 2 shows both intra- and intermolecular hydrogen bonding between the
coordinated water and triflates. The 19F NMR spectra of 1 and 2 display coupling between
the triflate groups; 19F-19F NOESY suggests that this arises from both through-bond and
through-space coupling. The reaction of 1 with 10 equiv of water results in the rapid formation
of a species assigned as the cationic diaqua complex [Ru(dppe)(CO)(H2O)2(OSO2CF3)][OSO2-
CF3] (3). Over a longer period of time, further reaction occurs to form the triaqua carbonyl
complex [Ru(dppe)(CO)(H2O)3][OSO2CF3]2 (4), which has also been characterized by X-ray
crystallography. The structure of 4 indicates that all three water ligands participate in
hydrogen bonding. Complex 4 is unstable in the absence of water, re-forming a mixture of
1 and 2.
In tr od u ction
metathesis polymerization (ROMP) of functionalized
norbornenes6 and the isomerization of allylic alcohols
and ethers.7 Recent studies of organometallic rhenium
and technetium aqua complexes have focused on their
potential applications in nuclear medicine.8
While water is regarded as a very common ligand in
coordination chemistry, far fewer examples are known
of organometallic aqua complexes, since a metal center
wants to be either “hard” or “soft”, but not usually both
at the same time.1 It is precisely this contradiction that
makes organometallic aqua complexes of special interest
in terms of their reactivity. The coordinated water can
undergo chemical transformation to hydroxy2 or oxo3
ligands, act as a supporting ligand for bond activation
reactions,4 or simply be displaced to yield a coordina-
tively unsaturated metal fragment. This last area has
received the most attention because of the potential
applications in organic synthesis and catalysis. Rhod-
ium(III) aqua complexes have been reported to catalyze
alkene polymerization,5 while aqua complexes of ruthe-
nium(II) have proved effective for the ring-opening
It has been proposed that the ruthenium(II) oxidation
state is particularly suited for bonding conventional
organometallic ligands such as CO and, at the same
time, binding to water.1a In this respect, we now wish
to report the synthesis, structural characterization, and
preliminary reactivity studies of two new ruthenium-
(II) carbonyl aqua complexes containing a dppe ligand
(dppe ) Ph2PCH2CH2PPh2). The complexes can be
readily prepared by reactions of the new triflate complex
Ru(dppe)(CO)2(OSO2CF3)2 with water either in the solid
state or in solution. Weakly coordinating anionic ligands
such as triflate are recognized as facile leaving groups
that can be readily displaced under mild conditions.9
When the incoming ligand is water, the free triflate
anion also serves a secondary role in stabilizing the low-
valent aqua complexes through hydrogen-bonding in-
teractions.10
* To whom correspondence should be addressed. E-mail:
chsmkw@bath.ac.uk.
† University of Bath.
‡ University of East Anglia.
(1) Selected references: (a) Ko¨lle, U. Coord. Chem. Rev. 1994, 135/
136, 623. (b) Eisen, M. S.; Haskel, A.; Chen, H.; Olmstead, M. H.;
Smith, D. P.; Maestre, M. F.; Fish, R. H. Organometallics 1995, 14,
2806. (c) Stebler-Ro¨thlisberger, M.; Hummel, W.; Pittet, P.-A.; Bu¨rgi,
H.-B.; Ludi, A.; Merbach, A. E. Inorg. Chem. 1988, 27, 1358. (d) Ko¨lle,
U.; Flunkert, G.; Go¨rissen, R.; Schmidt, M. U.; Englert, U. Angew.
Chem., Int. Ed. Engl. 1992, 31, 440. (e) Ganja, E. A.; Rauchfuss, T. B.;
Stern, C. L. Organometallics 1991, 10, 270.
(2) (a) Bryndza, H. E.; Tam, W. Chem. Rev. 1988, 88, 1163. (b) Burn,
M. J .; Fickes, M. G.; Hartwig, J . F.; Hollander, F. J .; Bergman, R. G.
J . Am. Chem. Soc. 1993, 115, 5875.
(3) Nugent, W. A.; Mayer, J . M. Metal Ligand Multiple Bonds;
Wiley: New York, 1988.
(6) (a) McGrath, D. V.; Grubbs, R. H.; Ziller, J . W. J . Am. Chem.
Soc. 1991, 113, 3611. (b) Hillmyer, M. A.; Lepetit, C.; McGrath, D. V.;
Novak, B. M.; Grubbs, R. H. Macromolecules 1992, 25, 3345.
(7) McGrath, D. V.; Grubbs, R. H. Organometallics 1994, 13, 224.
(8) (a) Alberto, R.; Egli, A.; Abram, U.; Hegetschweiler, K.; Gramlich,
V.; Schubiger, P. A. J . Chem. Soc., Dalton Trans. 1984, 2815. (b) Egli,
A.; Hegetschweiler, K.; Alberto, R.; Abram, U.; Schibli, R.; Hedinger,
R.; Gramlich, V.; Kissner, R.; Schubiger, P. A. Organometallics 1997,
17, 11833. (c) Alberto, R.; Schibli, R.; Egli, A.; Schubiger, A. P.; Abram,
U.; Kaden, T. A. J . Am. Chem. Soc. 1998, 120, 7987.
(4) J ohansson, L.; Ryan, O. B.; Tilset, M. J . Am. Chem. Soc. 1999,
121, 1974.
(5) Wang, L.; Lu, R. S.; Bau, R.; Flood, T. C. J . Am. Chem. Soc. 1993,
115, 6999.
(9) Beck, W.; Su¨nkel, K. Chem. Rev. 1988, 88, 1405.
(10) (a) Harding, P. A.; Preece, M.; Robinson, S. D.; Henrick, K.
Inorg. Chim. Acta 1986, 11, L31. (b) Takahashi, Y.; Akita, M.; Hikichi,
S.; Moro-oka, Y. Inorg. Chem. 1998, 37, 3186.
10.1021/om990411s CCC: $15.00 © 1999 American Chemical Society
Publication on Web 08/31/1999

Organometallic Aqua Complexes of Ru(II)
Organometallics, Vol. 18, No. 20, 1999 4069
Resu lts a n d Discu ssion
Syn th esis a n d Ch a r a cter iza tion of Ru (d p p e)-
(CO)2(OSO2CF 3)2 (1). Treatment of a dichloromethane
solution of all-cis-Ru(dppe)(CO)2Cl2 (dppe ) Ph2PCH2-
CH2PPh2) with 2.2 equiv of AgOSO2CF3 gives a pale
yellow solution from which the complex Ru(dppe)(CO)2-
(OSO2CF3)2 (1) may be isolated in reasonable yield. The
spectroscopic data are consistent with the structure
shown in eq 1.11
F igu r e 1. ORTEX diagram of Ru(dppe)(CO)2(OSO2CF3)2
(1). Thermal ellipsoids are shown at the 30% level.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Ru (d p p e)(CO)2(OSO2CF 3)2 (1)
Ru(1)-C(1)
Ru(1)-C(2)
Ru(1)-O(6)
Ru(1)-O(3)
Ru(1)-P(1)
Ru(1)-P(2)
S(1)-O(4)
S(1)-O(5)
S(1)-O(3)
S(1)-C(3)
C(3)-F(1)
1.859(7)
1.992(7)
2.182(4)
2.197(4)
2.324(2)
2.418(2)
1.396(6)
1.441(7)
1.480(4)
1.803(11)
1.288(12)
C(3)-F(3)
C(3)-F(2)
S(2)-O(8)
S(2)-O(7)
S(2)-O(6)
S(2)-C(4)
C(4)-F(6)
C(4)-F(4)
C(4)-F(5)
C(1)-O(1)
C(2)-O(2)
1.326(10)
1.329(10)
1.407(5)
1.417(6)
1.488(4)
1.818(11)
1.225(13)
1.287(10)
1.32(2)
The IR spectrum displays two carbonyl bands at 2106
and 2030 cm-1 of equal intensity consistent with a cis
geometry. These peaks are shifted 26-27 cm-1 to higher
frequency relative to the dichloride precursor (2079 and
2004 cm-1), which reflects the weaker π-donor ability
of triflate compared to chloride. Bands associated with
1.152(7)
1.126(8)
coordinated triflate (v(SO) at 1013 and 1329 cm-1
,
C(1)-Ru(1)-C(2)
C(1)-Ru(1)-O(3)
C(2)-Ru(1)-O(3)
O(6)-Ru(1)-O(3)
C(1)-Ru(1)-P(1)
C(2)-Ru(1)-P(1)
O(6)-Ru(1)-P(1)
O(3)-Ru(1)-P(1)
C(1)-Ru(1)-P(2)
C(2)-Ru(1)-P(2)
O(6)-Ru(1)-P(2)
O(3)-Ru(1)-P(2)
90.0(3)
92.8(2)
95.8(2)
85.8(2)
93.0(2)
91.9(2)
P(1)-Ru(1)-P(2)
O(4)-S(1)-O(5)
O(4)-S(1)-O(3)
O(5)-S(1)-O(3)
O(4)-S(1)-C(3)
O(5)-S(1)-C(3)
84.30(6)
118.5(5)
114.0(4)
113.2(3)
102.0(5)
103.8(5)
102.6(4)
115.2(5)
114.9(3)
113.8(3)
104.8(6)
103.9(6)
v(CF3) at 1199 and 1232 cm-1) are observed at lower
frequency.12 The 31P{1H} NMR spectrum of 1 in CDCl3
shows two doublet resonances for the dppe ligand. The
13C{1H} NMR spectrum exhibits two carbonyl reso-
nances with coupling constants indicating a geometry
in which the carbons are cis to one phosphorus atom
and trans to the other. The room-temperature 19F NMR
spectrum shows two quartet resonances at δ -76.91 (J
) 3.45 Hz) and δ -77.66 (J ) 3.45 Hz) for the two
inequivalent triflate ligands; 19F-19F COSY shows
beyond doubt that this splitting arises from coupling of
the CF3 groups. No changes are observed in either the
19F or 31P{1H} NMR spectra of 1 in CD2Cl2 between 30
°C and -80 °C, suggesting (i) that the orientations of
the triflate groups do not change with respect to each
other with temperature and (ii) that there is no flux-
ionality involving triflate dissociation as seen in other
Ru-OSO2R complexes (R ) CH3, CF3).13
88.34(12) O(3)-S(1)-C(3)
170.41(12) O(8)-S(2)-O(7)
88.6(2)
175.9(2)
90.77(12) O(8)-S(2)-C(4)
88.16(13) O(7)-S(2)-C(4)
O(8)-S(2)-O(6)
O(7)-S(2)-O(6)
lography were grown from CH2Cl2/hexane. The OR-
TEX14 diagram of 1 (Figure 1) shows the expected
octahedral coordination geometry about the ruthenium
center with the dppe ligand trans to one carbonyl and
one triflate. Selected bond distances and angles are
given in Table 1. The bite angle for the phosphine of
84.30(6)° is comparable to that in related ruthenium
complexes.15 There are relatively few structurally char-
acterized ruthenium triflate complexes.16 The Ru-O
bond distances of 2.197(4) Å for Ru-O(3) and 2.182(4)
Å for Ru-O(6) are shorter than those in the bis(triflate)
phosphine complex Ru(Cyttp)(CO)(OSO2CF3)2 (Cyttp )
PhP(CH2CH2CH2PCy2)2; distances of 2.221(3) and 2.233-
Cr ysta l Str u ctu r e of Ru (d p p e)(CO)2(OSO2CF 3)2
(1). Colorless crystals of 1 suitable for X-ray crystal-
(11) The analogous ruthenium amine triflate complexes Ru(N-N)-
(CO)2(OSO2CF3)2 (N-N ) bpy, phen) have been reported by Deacon
and co-workers: (a) Black, D. St. C.; Deacon, G. B.; Thomas, N. C.
Aust. J . Chem. 1982, 35, 2445. (b) Black, D. St. C.; Deacon, G. B.;
Thomas, N. C. Polyhedron 1983, 2, 409.
(12) Lawrance, G. A. Chem. Rev. 1986, 86, 17.
(14) McArdle, P. J . Appl. Crystallogr. 1994, 27, 438.
(15) (a) Gargaluk, J . D.; Berry, A. J .; Noirot, M. D.; Gladfelter, W.
L. J . Am. Chem. Soc. 1992, 114, 8933. (b) Gargulak, J . D.; Gladfelter,
W. L. Inorg. Chem. 1994, 33, 253.
(13) (a) Bailey, O. H.; Ludi, A. Inorg. Chem. 1985, 24, 2582. (b)
Harding, P. A.; Robinson, S. D.; Henrick, K. J . Chem. Soc., Dalton
Trans. 1988, 415.

4070 Organometallics, Vol. 18, No. 20, 1999
Mahon et al.
(3) Å)16a but significantly longer than those in the more
electrophilic half-sandwich complex (η5-C5(CH3)5)Ru(NO)-
(OSO2CF3)2 (Ru-O distances of 2.125(5) and 2.133(5)
Å).16b The triflate groups in 1 clearly point away from
one another in the crystal structure with the closest
intramolecular F-F interaction of 8.54 Å. There is a
significant difference in the Ru-CO bond distances
(Ru-C(1) ) 1.859(7) Å and Ru-C(2) ) 1.992(7) Å),
reflecting the different trans effects of the phosphine
and triflate ligands.
P r ep a r a tion a n d X-r a y Str u ctu r e of Ru (d p p e)-
(CO)(H2O)(OSO2CF 3)2 (2). During the synthesis of 1,
we noted on occasions in the IR spectrum the appear-
ance of a second product 2 as a single carbonyl band at
2001 cm-1. This peak is more intense if the glassware
is not rigorously flame-dried prior to use, suggesting
that this species arises from reaction with water. We
assign this as the carbonyl aqua complex Ru(dppe)(CO)-
(H2O)(OSO2CF3)2 (2) (eq 2). Exposure of a solid sample
of 1 to atmospheric moisture for 3 weeks gives 2 in
almost quantitative yield.
F igu r e 2. ORTEX diagram of Ru(dppe)(CO)(H2O)(OSO2-
CF3)2 (2). Thermal ellipsoids are shown at the 30% level.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Ru (d p p e)(CO)(H2O)(OSO2CF 3)2 (2)
Ru(1)-C(5)
Ru(1)-O(4)
Ru(1)-O(8)
Ru(1)-O(1)
Ru(1)-P(2)
Ru(1)-P(1)
F(1)-C(4)
F(2)-C(4)
F(3)-C(4)
F(4)-C(3)
F(5)-C(3)
1.817(8)
2.187(4)
2.198(5)
2.199(4)
2.300(2)
2.331(2)
1.354(11)
1.250(11)
1.311(12)
1.308(10)
1.347(10)
F(6)-C(3)
S(1)-O(2)
S(1)-O(3)
S(1)-O(1)
S(1)-C(3)
S(2)-O(5)
S(2)-O(6)
S(2)-O(4)
S(2)-C(4)
O(7)-C(5)
1.255(11)
1.395(5)
1.428(5)
1.472(4)
1.827(11)
1.407(6)
1.430(5)
1.473(4)
1.814(12)
1.163(8)
C(5)-Ru(1)-O(4)
C(5)-Ru(1)-O(8)
O(4)-Ru(1)-O(8)
C(5)-Ru(1)-O(1)
O(4)-Ru(1)-O(1)
O(8)-Ru(1)-O(1)
C(5)-Ru(1)-P(2)
O(4)-Ru(1)-P(2)
O(8)-Ru(1)-P(2)
O(1)-Ru(1)-P(2)
C(5)-Ru(1)-P(1)
O(4)-Ru(1)-P(1)
O(8)-Ru(1)-P(1)
O(1)-Ru(1)-P(1)
P(2)-Ru(1)-P(1)
177.0(2)
94.4(2)
83.8(2)
93.5(3)
84.0(2)
O(2)-S(1)-O(3)
O(2)-S(1)-O(1)
O(3)-S(1)-O(1)
O(2)-S(1)-C(3)
O(3)-S(1)-C(3)
O(1)-S(1)-C(3)
O(5)-S(2)-O(6)
O(5)-S(2)-O(4)
O(6)-S(2)-O(4)
O(5)-S(2)-C(4)
O(6)-S(2)-C(4)
O(4)-S(2)-C(4)
S(1)-O(1)-Ru(1)
S(2)-O(4)-Ru(1)
O(7)-C(5)-Ru(1)
117.1(4)
114.5(3)
113.4(3)
103.6(5)
104.2(5)
101.5(4)
116.7(4)
113.4(3)
114.0(3)
105.9(5)
103.5(5)
101.1(4)
131.2(3)
128.8(3)
177.5(6)
1
The H NMR spectrum of 2 in CDCl3 shows a singlet
88.8(2)
93.5(2)
at δ 5.85 for the coordinated water, while two doublet
resonances in the 31P{1H} NMR spectrum indicates that
the two ends of the dppe ligand are in different environ-
ments. The 13C{1H} NMR spectrum contains a single
carbonyl resonance at δ 197.1 with coupling to two cis
phosphorus nuclei (J ) 17.7 Hz). The 19F NMR spectrum
of 2 is similar to that of 1 and shows two quartet
resonances for the coordinated triflate ligands, although
the 19F-19F coupling is marginally larger (3.84 Hz) than
that seen in 1. Both the 19F and 31P{1H} NMR spectra
are unchanged between 25 and -60 °C.
89.03(12)
91.86(14)
172.90(12)
89.0(2)
92.92(12)
175.33(13)
94.16(13)
84.73(7)
The solid-state structure of 2 was established by X-ray
crystallography, as shown in Figure 2. The triflate
groups adopt an orientation very similar to that found
in the structure of 1. The water ligand is located trans
to P(1) with a Ru-O(8) distance of 2.198(5) Å (Table 2).
This distance is close to that found in the related
ruthenium(II) complex Ru(PPh3)2(CO)(H2O)(OSO2
p-C6H4CH3)2 (Ru-O ) 2.202(6) Å)13b but substantially
longer than the sum of the Pauling covalent radii (1.99
Å) for ruthenium and oxygen, demonstrating the weak
nature of the Ru-O bond.17 There are close contacts
between the coordinated water ligand and the two
(16) (a) Blosser, P. W.; Gallucci, J . D.; Wojcicki, A. Inorg. Chem.
1992, 31, 2376. (b) Svetlanova-Larsen, A.; Zoch, C. R.; Hubbard, J . L.
Organometallics 1996, 15, 3076. (c) Sutter, J .-P.; J ames, S. L.;
Steenwinkel, P.; Karlen, T.; Grove, D. M.; Veldman, N.; Smeets, W. J .
J .; Spek, A. L.; van Koten, G. Organometallics 1996, 15, 941. (d)
Germel, C.; Kalt, D.; Mereiter, K.; Sapunov, V. N.; Schmid, R.;
Kirchner, K. Organometallics 1997, 16, 427. (e) Abbenhuis, R. A. T.
M.; del Rio, I.; Bergshoef, M. M.; Boersma, J .; Veldman, N.; Spek, A.
L.; van Koten, G. Inorg. Chem. 1998, 37, 1749. (f) Fong, T. P.; Lough,
A. J .; Morris, R. H.; Mezzetti, A.; Rocchini, E.; Rigo, P. J . Chem. Soc.,
Dalton Trans. 1998, 2111.

Organometallic Aqua Complexes of Ru(II)
Organometallics, Vol. 18, No. 20, 1999 4071
is some through-space F-F coupling in 1 and 2, there
must also be a contribution from through-bond coupling.
Rea ction of Ru (d p p e)(CO)2(OSO2CF 3)2 w ith Wa -
ter in Solu tion . The surprisingly facile displacement
of a carbonyl ligand in 1 by water in the solid state
prompted us to investigate the reactivity with water in
solution. Hubbard and co-workers have reported quite
different behavior for the reactions of water with the
triflate complexes Cp′Ru(NO)(OSO2CF3)2 (Cp′ ) η5-C5-
(CH3)5, η5-C5(CH3)4(CH2CH3)) and Rh(PPh3)2(CO)(OSO2-
CF3).16b,20 Addition of 10 equiv of water to a solution of
1 in CDCl3 results in an immediate reaction, as shown
by 31P{1H} NMR spectroscopy, which indicates the
formation of at least six dppe-containing products, none
of which correspond to 2. After 12 h at room tempera-
ture the 31P NMR spectrum contains only one product,
a singlet at δ 66.1. The 19F NMR spectrum shows two
resonances, a sharp singlet at δ -77.66 and a broader
singlet at δ -77.72, while the solution IR spectrum
contains a single carbonyl band at 1997 cm-1. We
tentatively assign this species as the cationic diaqua
complex [Ru(dppe)(CO)(H2O)2(OSO2CF3)][OSO2CF3] (3),
which is formed upon displacement of a carbonyl group
and a triflate group from the bis(triflate) complex 1 by
water. The two water ligands must be located trans to
the bidentate dppe ligand to account for the single peak
in the 31P NMR spectrum (eq 3). We have been unable
F igu r e 3. Intra- and intermolecular hydrogen-bonding
interactions in 2.
triflate groups in the asymmetric unit as presented
(O(8)-H‚‚‚O(6) ) 2.723(7) Å, O(8)-H‚‚‚O(3) ) 2.835(7)
Å), supporting intramolecular hydrogen bonding (Figure
3). The ligated water also exhibits a close contact with
a triflate in an adjacent molecule (O(8)-H‚‚‚O(3A) )
3.006(8) Å) generated by the symmetry operation -x,
-y, -z, suggesting the presence of intermolecular
hydrogen bonding.
The weakly coordinated water ligand in Ru(dppe)-
(CO)(H2O)(OSO2CF3)2 proves to be substitutionally
labile. Exposure of a dichloromethane solution of 2 to
CO for 10 min results in quantitative conversion back
to 1.
19F -19F NOESY Stu d ies of 1 a n d 2. At first sight,
the coupling between the triflate groups seen in the 19F
NMR spectra of both 1 and 2 appears to be too large for
through-bond coupling (the fluorines are separated by
eight bonds) and suggests through-space coupling,
which is well-established in organofluorine compounds.18
From a recently published correlation19 of coupling
constant (J FF) with distance (dFF) based on a series of
difluorocyclophanes with rigidly constrained geometries,
a
19F-19F coupling constant of 3.45 Hz in 1 yields a
distance of 3.51 Å between fluorine atoms. The X-ray
structure gives the closest intramolecular interaction at
8.54 Å; while the solution and solid-state structures
must not necessarily be the same, we have attempted
to establish through-space interactions of the triflates
in solution by 19F-19F NOESY.
A
19F-19F NOESY spectrum of a CDCl3 solution
containing a mixture of 1 and 2 (and also a small
amount of free triflate) was recorded at 300 K with a
mixing time (τm) of 400 ms. The spectrum shows that
the two triflate groups in 1 exchange with each other
and also with free triflate. Intra- and intermolecular
exchange (with free triflate) is also observed for 2. When
the temperature is lowered to 255 K, these exchange
processes are halted and weak NOE cross-peaks (ca. 1%)
are observed between the two CF3 groups in 1 and
between the CF3 groups in 2. The observation of only a
weak NOE effect appears to indicate that, while there
to characterize this species further due to its reactivity
in solution. Removal of the water/CDCl3 in vacuo and
redissolution of the residue in dry CDCl3 regenerates
complexes 1 and 2, in a 2:1 ratio, as shown by 31P{1H}
NMR spectroscopy.
Similarly, when 1 is left in a CDCl3/water solution
for 1 day, the signal arising from 3 disappears and a
new singlet resonance grows in at δ 51.9 in the 31P{1H}
NMR spectrum. We have isolated this complex and
identified it as the dicationic triaqua carbonyl complex
[Ru(dppe)(CO)(H2O)3][OSO2CF3]2 (4) by NMR, IR, and
X-ray crystallography (eq 3).
(17) Pauling, L. The Nature of the Chemical Bond, 3rd ed.; Cornell
University Press: Ithaca, NY, 1960.
(18) (a) Gu¨nther, H. NMR Spectroscopy, 2nd ed.; Wiley: Chichester,
U.K., 1995. (b) Mallory, F. B.; Mallory, C. W.; Ricker, W. M. J . Am.
Chem. Soc. 1975, 97, 4770.
(19) Ernst, L.; Ibrom, K. Angew. Chem., Int. Ed. Engl. 1995, 34,
1881.
(20) Svetlanova-Larsen, A.; Hubbard, J . L. Inorg. Chem. 1996, 35,
3073.

4072 Organometallics, Vol. 18, No. 20, 1999
Mahon et al.
located trans to the dppe ligand, and one is trans to CO.
The Ru-O bond lengths for the two equivalent waters
are of comparable length (Ru-O(2) ) 2.180(2) Å, Ru-
O(3) ) 2.170(2) Å), while the Ru-O distance trans to
CO is slightly shorter (Ru-O(4) ) 2.157(2) Å). Analysis
of the supramolecular array reveals that the gross
structure is dominated by hydrogen-bonding chains
parallel to the c axis of the unit cell and that these are
propagated by two sets of alternating interactions
(Figure 5). Each dicationic center is hydrogen-bonded
to the lattice neighbor (generated as a consequence of
the inversion center) closest to its ligated waters. In
particular, the two protons attached to both O(2) and
O(3), along with one of the protons attached to O(4),
interact with the oxygen atoms of the triflate counter-
ions from the same asymmetric unit along with those
generated by the inversion center. These units are then
“cemented” further along c by interaction of the remain-
ing proton on O(4) and a lattice water molecule (O(12)).
This cementing is consolidated by interaction of O(12)
with O(5) of a triflate ion.
Initial studies have shown that 4 readily dissociates
in the absence of water. Although 4 is not soluble in
D2O, the 31P{1H} NMR spectrum recorded immediately
upon dissolution of crystalline material in dry CDCl3
or CD2Cl2 shows large resonances for 1 and 2, a smaller
signal for 4, and a singlet resonance for a fourth,
unidentified species at δ 67.7. After 1 week in solution,
this last complex is the only remaining product. Addi-
tion of excess water to the solution results in the re-
formation of 4 in quantitative yield. We are currently
investigating this solution reactivity in greater detail
to determine the identity of this singlet product. The
interconversion of 1, 2, 3, and 4 is summarized in
Scheme 1.
F igu r e 4. ORTEX diagram of [Ru(dppe)(CO)(H2O)3][OSO2-
CF3]2 (4). Thermal ellipsoids are shown at the 30% level.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for [Ru (d p p e)(CO)(H2O)3][OSO2CF 3]2 (4)
Ru(1)-C(1)
Ru(1)-O(4)
Ru(1)-O(3)
Ru(1)-O(2)
Ru(1)-P(2)
Ru(1)-P(1)
S(1)-O(5)
S(1)-O(6)
S(1)-O(7)
S(1)-C(4)
1.833(3)
2.157(2)
2.170(2)
2.180(2)
2.2654(7)
2.2876(7)
1.420(3)
1.432(3)
1.450(2)
1.822(3)
1.431(2)
S(2)-O(8)
S(2)-O(9)
S(2)-C(5)
O(1)-C(1)
C(4)-F(3)
C(4)-F(2)
C(4)-F(1)
C(5)-F(5)
C(5)-F(6)
C(5)-F(4)
1.435(2)
1.446(2)
1.813(4)
1.145(3)
1.317(4)
1.320(4)
1.325(4)
1.309(4)
1.322(4)
1.333(4)
S(2)-O(10)
C(1)-Ru(1)-O(4) 176.53(10) P(2)-Ru(1)-P(1)
85.44(3)
116.5(2)
115.1(2)
112.87(14)
103.5(2)
104.0(2)
C(1)-Ru(1)-O(3)
O(4)-Ru(1)-O(3)
C(1)-Ru(1)-O(2)
O(4)-Ru(1)-O(2)
O(3)-Ru(1)-O(2)
C(1)-Ru(1)-P(2)
O(4)-Ru(1)-P(2)
O(3)-Ru(1)-P(2)
95.47(10) O(5)-S(1)-O(6)
81.40(8) O(5)-S(1)-O(7)
96.19(10) O(6)-S(1)-O(7)
Con clu sion s
82.17(8)
86.80(8)
86.05(8)
95.70(6)
95.09(6)
O(5)-S(1)-C(4)
O(6)-S(1)-C(4)
O(7)-S(1)-C(4)
We have prepared and fully characterized two new
organometallic aqua complexes of ruthenium(II) by
facile substitution of carbonyl and triflate groups in Ru-
(dppe)(CO)2(OSO2CF3)2. Preliminary studies indicate
that the coordinated water ligands in Ru(dppe)(CO)-
(H2O)(OSO2CF3)2 (2) and [Ru(dppe)(CO)(H2O)3]2+ (4) are
labile, which may offer a route to coordinatively unsat-
urated metal complexes with applications in organic
synthesis. We are currently investigating the reactivity
of 4 with this aim in mind, as well as studying more
fundamental properties such as ease of deprotonation
of the coordinated water ligands and the kinetics of
intra- and intermolecular exchange. The paucity of
studies in this area1b,c,21 suggests that our studies
should reveal important new information about organo-
metallic aqua complexes.
102.64(14)
O(10)-S(2)-O(8) 114.4(2)
O(10)-S(2)-O(9) 114.75(14)
O(2)-Ru(1)-P(2) 176.92(6)
O(8)-S(2)-O(9)
O(10)-S(2)-C(5) 104.8(2)
114.96(14)
C(1)-Ru(1)-P(1)
O(4)-Ru(1)-P(1)
O(3)-Ru(1)-P(1) 176.21(6)
88.31(8)
94.81(6)
O(8)-S(2)-C(5)
O(9)-S(2)-C(5)
O(1)-C(1)-Ru(1)
103.0(2)
102.8(2)
77.4(2)
O(2)-Ru(1)-P(1)
92.51(6)
The 19F NMR spectrum of 4 shows a single, sharp
resonance at δ -78.63, which we assign to the uncoor-
1
dinated triflate groups. The H NMR spectrum shows
a very broad resonance for the coordinated water ligands
at δ 4.94; the resonance for free water at δ 1.73 is also
broad, suggesting exchange between bound and free
water. The IR spectrum of 4 in KBr contains a single
carbonyl band at 1990 cm-1 and a band associated with
uncoordinated triflate at 1232 cm-1
.
Exp er im en ta l Section
Isolation of [Ru (dppe)(CO)(H2O)3][OSO2CF3]2 (4).
The triaqua complex crystallizes slowly from CDCl3/
water solution as pale yellow cubes, which prove to be
suitable for a structural determination. An ORTEX
diagram14 of the structure of 4 is shown in Figure 4.
Selected bond lengths and angles are given in Table 3.
The asymmetric unit contains the octahedral ruthenium
dicationic complex, two free triflate anions, and 1.8
molecules of free water. Two of the aqua ligands are
Gen er a l Com m en ts. The compounds were synthesized and
handled under argon using standard Schlenk and high-
vacuum techniques. Ether and hexanes were distilled from
purple solutions of sodium dispersion/benzophenone, and CH2-
Cl2 was distilled from either CaH2 or P2O5. Water was doubly
distilled. CDCl3 and CD2Cl2 (Apollo Scientific Ltd.) were
(21) Aebischer, N.; Churlaud, R.; Dolci, L.; Frey, U.; Merbach, A. E.
Inorg. Chem. 1998, 37, 5915.

Organometallic Aqua Complexes of Ru(II)
Organometallics, Vol. 18, No. 20, 1999 4073
F igu r e 5. Stereoplot illustrating the hydrogen-bonding interactions in the crystal lattice of 4.
Sch em e 1
vacuum-transferred from CaH2. Silver triflate was purchased
from Lancaster Synthesis and used as received. all-cis-Ru-
(dppe)(CO)2Cl2 was prepared according to the method of
Barnard.22 Spectroscopic data for this compound have already
been reported in the literature.17a NMR spectra were recorded
on a J EOL EX 270 NMR spectrometer. The 19F-19F NOESY
experiments were carried out on a Bruker AMX 500 NMR
spectrometer at the University of York. 1H NMR spectra were
referenced to residual CHCl3 at δ 7.27. 19F NMR spectra were
referenced to external CFCl3 (δ 0.00). 13C NMR spectra were
referenced to CDCl3 at δ 77.0. 31P NMR chemical shifts were
referenced externally to 85% H3PO4 (δ 0.0). IR spectra were
recorded as KBr disks or in either CDCl3 or CH2Cl2 solution
on Nicolet Prote´ge´ 460 or Impact 410 FTIR spectrometers.
Elemental analyses were performed at the Universities of East
Anglia and Bath.
Ru (d p p e)(CO)2(OSO2CF 3)2 (1). Silver triflate (272 mg,
1.06 mmol) was added to a Schlenk tube containing a stirred
solution of cis-Ru(dppe)(CO)2Cl2 (302 mg, 0.48 mmol) in CH2-
Cl2 (10 mL). The solution was stirred at room temperature for
(22) Barnard, C. F. J . D. Phil. Thesis, The University of York, York,
U.K., 1978.

4074 Organometallics, Vol. 18, No. 20, 1999
Mahon et al.
Ta ble 4. Exp er im en ta l Da ta for th e X-r a y Diffr a ction Stu d ies of Com p ou n d s 1, 2, a n d 4
1
2
4
empirical formula
fw
C
30H24FO8P2RuS2‚1.2H2O
C29H28F6O8P2RuS2
845.64
C29H30F6O10P2RuS2‚1.8H2O
912.09
875.24
T/K
293(2)
293(2)
198(2)
λ
0.710 73
monoclinic
P21/c
11.637(6)
0.710 73
monoclinic
P21/n
0.710 69
monoclinic
P21/c
cryst syst
space group
a/Å
11.603(2)
11.719(1)
b/Å
18.452(2)
18.396(4)
23.365(3)
c/Å
17.227(3)
16.840(1)
13.851(2)
â/deg
100.72(3)
3635(2)
4
1.600
0.715
1760
100.03(1)
3539.5(10)
4
1.587
0.728
102.54(1)
3702.1(8)
4
1.636
0.710
1848
U/Å3
Z
D
calcd/g cm-3
µ/mm-1
F000
1704
cryst dimens/mm
θ range/deg
index ranges
0.09 × 0.10 × 0.10
0.08 × 0.10 × 0.10
2.10 f 25.46
-13 e h e 13; -22 e k e 22;
-20 e l e 20
11 981
6362 (R(int) ) 0.0424)
full-matrix least squares on F2
6357/0/436
0.15 × 0.15 × 0.15
2.24 f 25.00
0 e h e 13; 0 e k e 27;
-16 e l e 16
7045
6495 (R(int) ) 0.0106)
full-matrix least squares on F2
6488/6/494
1.63 f 24.58
-13 e h e 13; -21 e k e 21;
-20 e l e 20
11 878
6091 (R(int) ) 0.0481)
full-matrix least squares on F2
6086/0/447
no. of rflns collected
no. of indep rflns
refinement method
no. of data/restraints/
params
goodness of fit on F2
R1, wR2 (I > 2σ(I))
R1, wR2 (all data)
largest diff peak and
hole, e Å-3
0.970
0.942
0.981
0.0590, 0.1606
0.0953, 0.1885
1.087 and -0.570
0.0580, 0.1531
0.1101, 0.1900
0.765 and -0.654
0.0302, 0.0731
0.0369, 0.0835
0.701 and -0.538
weighting scheme/w
1/[σ2(Fo2) + (0.1102P)2 + 0.0000P];
1/[σ2(Fo2) + (0.1027P)2 + 0.0000P];
1/[σ2(Fo2) + (0.0358P)2 +
2
2
2
P ) (Fo + 2Fc2)/3
P ) (Fo + 2Fc2)/3
6.4816P]; P ) (Fo + 2Fc2)/3
extinction coefficient
extinction expression
0.00039(11)
Fc* ) kFc[1 + 0.001Fc2λ3/
(sin 2θ)]-1/4
1 h and then filtered under argon. The filtrate was concen-
trated to 5 mL, and diethyl ether (20 mL) was added with
vigorous stirring to bring about the precipitation of a white
solid. The volume of the solution was then reduced by 50% to
maximize precipitation. The residual solvent was removed by
cannula to leave a white solid, which was washed with 5 mL
of diethyl ether and then dried under vacuum (186 mg, 0.22
mmol). Yield: 50%. 1H NMR (CDCl3, 270 MHz, 293 K): δ 2.75
(m, 2H, PCH2), 3.06 (m, 2H, PCH2), 7.35-7.85 (br, 20H,
PC6H5). 31P{1H} NMR: δ 44.5 (d, J PP ) 16.2 Hz), 66.3 (d, J PP
) 16.2 Hz). 19F NMR: δ -76.91 (q, J FF ) 3.45 Hz, CF3), -77.66
(q, J FF ) 3.45 Hz, CF3). 13C{1H} NMR: δ 186.0 (dd, J PC ) 108.0
Hz, J PC ) 9.9 Hz), 193.6 (t, J PC ) 14.9 Hz). IR (CH2Cl2, cm-1):
1 day. Crystals of 4 slowly precipitated from solution. 1H NMR
(CDCl3/H2O, 270 MHz, 293 K): δ 4.94 (br, 6H, H2O). 31P{1H}
NMR: δ 51.9 (s). 19F NMR: δ - 78.63 (s). IR (KBr, cm-1): 3306
br, 1990 vs, 1653 br, 1468 w, 1437 m, 1417 w, 1308 s, 1232 s,
1213 s, 1172 s, 1101 m, 1028 s, 816 w, 747 m, 717 m, 692 m,
636 s, 581 m, 529 m, 496 w. Anal. Found (calcd) for
RuC29H34P2O12S2F6‚1.8H2O: C, 38.56 (38.19); H, 3.57 (3.71).
X-r a y Exp er im en ta l Da ta . Crystal structure details for
1, 2, and 4 are summarized in Table 4. X-ray data for 1 and 2
were recorded on a Rigaku RAXIS II image plate, while the
data for 4 were collected on an Enraf-Nonius CAD 4 diffrac-
tometer. Crystals were mounted on glass fibers with epoxy
resin. In all cases, no absorption corrections were applied. The
structures were solved by direct methods using SHELXS23 and
all non-hydrogen atoms refined anisotropically using full-
matrix least squares (SHELXL-93)24 on F2.
2106 (ν(CO)), 2030 (ν(CO)). Anal. Found (calcd) for RuC30H24
P2O8S2F6‚1.2H2O: C, 41.76 (42.21); H, 2.90 (2.83).
-
Ru (d p p e)(CO)(H2O)(OSO2CF 3)2 (2). In a typical experi-
ment, a solid sample of 1 (40 mg, 0.047 mmol) was left in the
air at room temperature for 3 weeks. The sample, which slowly
changed color from white to brown, was periodically checked
by IR spectroscopy until only a single band for ν(CO) at 2001
cm-1 was seen. Recrystallization from CH2Cl2/hexane afforded
colorless crystals of 2 suitable for X-ray diffraction (26 mg,
Ack n ow led gm en t. M.K.W. wishes to thank Dr. S.
B. Duckett (University of York, York, U.K.) for help with
the 19F-19F NOESY experiments and discussions. We
acknowledge J ohnson Matthey plc for the loan of
ruthenium trichloride hydrate and the Universities of
East Anglia and Bath for financial support.
1
0.031 mol, 66% yield). H NMR (CDCl3, 270 MHz, 293 K): δ
2.50 (m, 2H, PCH2), 2.95 (m, 2H, PCH2), 5.85 (s, 2H, H2O),
7.38-7.95 (br, 20H, PC6H5). 31P{1H} NMR: δ 65.0 (d, J PP
)
Su p p or tin g In for m a tion Ava ila ble: X-ray crystallo-
graphic data, including tables of atomic coordinates, bond
lengths and angles, anisotropic displacement parameters,
hydrogen coordinates, and Ueq values and packing diagrams.
This material is available free of charge via the Internet at
http://pubs.acs.org.
19.3 Hz), 67.0 (d, J PP ) 19.3 Hz). 19F NMR: δ -77.63 (q, J FF
) 3.84 Hz, CF3), -78.19 (q, J FF ) 3.84 Hz, CF3). 13C{1H}
NMR: δ 197.0 (t, J PC ) 17.7 Hz). IR (CDCl3, cm-1): 2001 (ν-
(CO)). Anal. Found (calcd) for RuC29H26P2O8S2F6: C, 40.41
(40.80); H, 3.09 (3.11).
[Ru (d p p e)(CO)(H2O)3][OSO2CF 3]2 (4). A sample of 1 (13
mg, 0.015 mmol) was placed in a J . Youngs resealable NMR
tube and CDCl3 condensed in. Water (3 µL, 0.17 mmol) was
added by syringe, and the reaction was monitored by 31P{1H}
NMR spectroscopy. Complete conversion to 4 was observed in
OM990411S
(23) Sheldrick, G. M. Acta Crystallogr. 1990, 467-473, A46.
(24) Sheldrick, G. M. University of Go¨ttingen, Go¨ttingen, Germany,
1993.