Protonation reactions of [MH(Cl)(PPh3)2(norbornadiene)] (M = Ru, Os)

Article abstract of DOI:10.1021/om010029r

Protonation of [RuH(Cl)(PPh₃)₂(NBD)] (NBD = norbornadiene) in benzene with a limiting amount of HOTf gives [RuH(OTf)(PPh₃)₂(NBD)], norbornene, and [RuCl₂(PPh₃)₂]₂. In dichloromethane, [RuH(Cl)(PPh₃)₂(NBD)] reacts with a limiting amount of HOTf to give [RuH(OTf)(PPh₃)₂(NBD)], norbornene, and the trimetallic complex [Ru₃Cl₅(PPh₃)₆]OTf. In contrast, protonation of [OsH(Cl)(PPh₃)₂(NBD)] in benzene or dichloromethane with limiting HOTf only gives [OsH(OTf)(PPh₃)₂(NBD)]. In the protonation of [RuH(Cl)(PPh₃)₂(NBD)], the norbornene is likely produced through the intermediate [RuH(HCl)(PPh₃)₂(NBD)]OTf. The involvement of [RuH(HCl)(PPh₃)₂(NBD)]⁺ in the formation of norbornene is supported by theoretical calculations based on the B3LYP density functional theory. The fact that norbornene is not produced in the protonation of [OsH(Cl)(PPh₃)₂(NBD)] can be attributed to the stronger osmium-olefin interaction.

Full text of DOI:10.1021/om010029r

Organometallics 2001, 20, 4161-4169
4161
P r oton a tion Rea ction s of
[MH(Cl)(P P h 3)2(n or bor n a d ien e)] (M ) Ru , Os)
Sheng Hua Liu,† Sheng-Yong Yang,† Shu Tak Lo,† Zhitao Xu,† Weng Sang Ng,†
Ting Bin Wen,† Zhong Yuan Zhou,‡ Zhenyang Lin,*,† Chak Po Lau,‡ and
Guochen J ia*,†
Department of Chemistry, The Hong Kong University of Science and Technology,
Clear Water Bay, Kowloon, Hong Kong, and Department of Applied Biology & Chemical
Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
Received J anuary 16, 2001
Protonation of [RuH(Cl)(PPh3)2(NBD)] (NBD ) norbornadiene) in benzene with a limiting
amount of HOTf gives [RuH(OTf)(PPh3)2(NBD)], norbornene, and [RuCl2(PPh3)2]2. In
dichloromethane, [RuH(Cl)(PPh3)2(NBD)] reacts with a limiting amount of HOTf to give
[RuH(OTf)(PPh3)2(NBD)], norbornene, and the trimetallic complex [Ru3Cl5(PPh3)6]OTf. In
contrast, protonation of [OsH(Cl)(PPh3)2(NBD)] in benzene or dichloromethane with limiting
HOTf only gives [OsH(OTf)(PPh3)2(NBD)]. In the protonation of [RuH(Cl)(PPh3)2(NBD)], the
norbornene is likely produced through the intermediate [RuH(HCl)(PPh3)2(NBD)]OTf. The
involvement of [RuH(HCl)(PPh3)2(NBD)]+ in the formation of norbornene is supported by
theoretical calculations based on the B3LYP density functional theory. The fact that
norbornene is not produced in the protonation of [OsH(Cl)(PPh3)2(NBD)] can be attributed
to the stronger osmium-olefin interaction.
In tr od u ction
clude intramolecular hydrogen transfer from the dihy-
drogen ligand to the olefin ligand to give alkyl-hydride
complexes [MH(alkyl)Ln] and reductive elimination of
the hydride and alkyl ligands of [MH(alkyl)Ln]. In
hydrogenation of ketones involving hydride complexes
[MH(HB)Ln] where HB is potentially a proton donor,
concerted hydrogen transfer from M-H and HB to
ketones has been suggested.
When a halo hydride complex [MH(X)Ln] (X ) halide)
is treated with a protic acid, the proton could attack
either the hydride or the halide (or the metal).12 If the
metal center is electron deficient, the protonation reac-
tion could lead to the formation of either the dihydrogen
complex [M(X)(H2)Ln]+ or the hydrohalide complex [MH-
(HX)Ln]+. For example, protonation of [MH(X)L4] (M )
Ru, Os, L ) phosphine, or pyridine) has been used
conveniently to prepare dihydrogen complexes of the
type [M(X)(H2)L4]+.13,14 Although possible, hydrohalide
complexes of the type [MH(HX)L4]+ were usually not
obtained from these protonation reactions, probably
because the dihydrogen complexes [M(X)(H2)L4]+ are
thermodynamically more stable than the hydrohalide
complexes [MH(HX)L4]+. However, selective protonation
of halide ligands in [MH(X)Ln] has been observed in the
protonation reactions of chloro hydride complexes such
In the classic mechanisms of catalytic hydrogenation
of olefins, insertion of an olefin to a metal-hydrogen
bond followed by reductive elimination of hydride and
alkyl ligands have been recognized as the key steps.1
Recent studies on the chemistry of metal hydride
complexes suggest that unsaturated substrates such as
olefins, acetylenes, and ketones could also be hydroge-
nated through alternative pathways. For example,
olefins could be hydrogenated through alkyl-dihydrogen
complexes [M(R)(H2)Ln]2-6 or olefin-dihydrogen com-
plexes [M(H2)(olefin)Ln];2,6-8 ketones could be hydroge-
nated through hydride complexes [MH(HB)Ln] where
HB is potentially a proton donor (e.g., a coordinated
RNH2).9-11 In reactions involving olefin-dihydrogen
complexes [M(H2)(olefin)Ln], the elementary steps in-
† Hong Kong University of Science and Technology.
‡ Hong Kong Polytechnic University.
(1) Crabtree, R. H. The Organometallic Chemistry of the Transition
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(3) (a) Bianchini, C.; Meli, A.; Peruzzini, M.; Frediani, P.; Bohanna,
C.; Esteruelas, M. A.; Oro, L. A. Organometallics 1992, 11, 138. (b)
Bianchini, C.; Bohanna, C.; Esteruelas, M. A.; Frediani, P.; Meli, A.;
Oro, L. A.; Peruzzini, M. Organometallics 1992, 11, 3837.
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G. Organometallics 1997, 16, 34.
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Schweitzer, C. T.; D’Agostino, C. Inorg. Chem. 1994, 33, 6278. (c)
Rocchini, E.; Mezzetti, A.; Ru¨egger, H.; Burckhardt, U.; Gramlich, V.;
Del Zotto, A.; Martinuzzi, P.; Rigo, P. Inorg. Chem. 1997, 36, 711. (d)
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10.1021/om010029r CCC: $20.00 © 2001 American Chemical Society
Publication on Web 09/05/2001

4162 Organometallics, Vol. 20, No. 20, 2001
Liu et al.
Sch em e 1
as [OsH2Cl2(P(i-Pr)3)2],15a [PtHCl(P(t-Bu)2Me)2],12 and
[OsH2Cl(NO)(P(i-Pr)3)2].15b With this background in
mind, we have investigated the protonation reactions
of ruthenium and osmium complexes [MH(X)(olefin)Ln],
to see if complexes [M(X)(H2)(olefin)Ln]+ or [MH(HX)-
(olefin)Ln]+ could be observed and if these complexes
could be involved in the hydrogenation of the olefin
ligands. In this paper, we wish to describe the proto-
nation reactions of [MH(Cl)(PPh3)2(NBD)] (M ) Ru, Os)
with HOTf.
Stephenson’s group.18 The presence of complex 2 is
indicated by the appearance of a singlet signal at 41.5
ppm in the 31P{1H} NMR spectrum and a hydride signal
at -13.47 ppm in the 1H NMR spectrum. Complex 2
has been previously synthesized from the reaction of
[RuH(Cl)(PPh3)2(NBD)] with AgOTf.19 The norbornene
1
produced can be easily identified by the H NMR.
In the protonation reaction, the hydride complex
[RuH(OTf)(PPh3)2(NBD)] is presumably formed by pro-
tonation of the Cl ligand. The bimetallic complex [RuCl2-
(PPh3)2]2 (4) is presumably formed from the reaction of
[RuCl(PPh3)2]+ (generated in the course of formation of
norbornene) with HCl (generated by protolysis of the
chloride ligand of 1 to give [RuH(OTf)(PPh3)2(NBD)]).
In dichloromethane, [RuH(Cl)(PPh3)2(NBD)] (1) re-
acted with a limiting amount of HOTf to give [RuH-
(OTf)(PPh3)2(NBD)] (2), norbornene (3), and the unusual
trimetallic complex [Ru3Cl5(PPh3)6]OTf (5) (see Scheme
1). As indicated by an in situ NMR experiment, nor-
bornene and [RuH(OTf)(PPh3)2(NBD)] were produced in
approximately 1:1.8 ratio. In the protonation reaction,
the trimetallic complex [Ru3Cl5(PPh3)6]OTf (5) is pre-
sumably formed from the reaction of [RuCl(PPh3)2]+
(generated in the course of formation of norbornene)
with HCl (generated by protolysis of the chloride ligand
of 1 to give [RuH(OTf)(PPh3)2(NBD)]). Again, if excess
HOTf was used, complexes 2 and 5 could also be further
protonated to give a mixture of complexes which proved
to be difficult to characterize.
Resu lts a n d Discu ssion
P r oton a tion of [Ru H(Cl)(P P h 3)2(NBD)]. The prod-
ucts of the protonation reaction are solvent dependent.
[RuH(Cl)(PPh3)2(NBD)] (1)16 in C6D6 reacted with a
limiting amount of HOTf to give [RuH(OTf)(PPh3)2-
(NBD)] (2), norbornene (3), and [RuCl2(PPh3)2]2 (4)
(Scheme 1). As indicated by an in situ NMR experiment,
norbornene and [RuH(OTf)(PPh3)2(NBD)] were pro-
duced in a ratio of ca. 1:2.1. If excess HOTf was used,
complexes 2 and 4 could also be further protonated to
give a mixture of complexes which proved to be difficult
to characterize.
The products obtained from the protonation reaction
can be easily identified by 31P and 1H NMR spectros-
copy. The presence of the bimetallic complex 4 is
indicated by the appearance of two broad singlet signals
at 59.7 and 52.6 ppm in the in situ 31P{1H} NMR
spectrum. The 31P NMR property of complex 4 has been
previously studied by K. G. Caulton’s group17 and T. A.
Complex 5 can be isolated as a brown solid from the
reaction of [RuH(Cl)(PPh3)2(NBD)] (1) in dichloromethane
with aqueous HOTf. In the 31P{1H} NMR spectrum in
(15) (a) Kuhlman, R.; Streib, W. E.; Caulton, K. G. Inorg. Chem.
1995, 34, 1788. (b) Yandulov, D. V.; Streib, W. E.; Caulton, K. G. Inorg.
Chim. Acta 1998, 280, 125.
(16) Hallman, P. S.; McGarvey, B. R.; Wilkinson, G. J . Chem. Soc.
(A) 1968, 3143.
(17) Hoffman, P. R.; Caulton, K. G. J . Am. Chem. Soc. 1975, 97,
4221.
(18) Armit, P. W.; Boyd, A. S. F.; Stephenson, T. A. J . Chem. Soc.,
Dalton Trans. 1975, 1663.
(19) Lo, S. T.; Xu, Z.; Wen, T. B.; Ng, W. S.; Liu, S. H.; Zhou, Z. Y.;
Lin, Z.; Lau, C. P.; J ia, G. Organometallics 2000, 19, 4523.

Reactions of [MH(Cl)(PPh3)2(norbornadiene)]
Organometallics, Vol. 20, No. 20, 2001 4163
Sch em e 2
F igu r e 1. Molecular structure for the cation [Ru3Cl5-
(PPh3)6]+ showing 50% probability of thermal ellipsoids.
The phenyl rings of PPh3 have been omitted for clarity.
Ta ble 1. Cr ysta l Da ta a n d Refin em en t Deta ils for
[Ru 3Cl5(P P h 3)6]BP h 4‚2.5CH2Cl2
formula
fw
C132H110BCl5P6Ru3‚2.5CH2Cl2
2543.14
cryst syst
space group
a, Å
triclinic
P1h
15.028(2)
b, Å
20.370(3)
c, Å
20.687(3)
R, deg
â, deg
γ, deg
V, Å3
88.228(4)
86.974(4)
87.961(3)
6316.9
reported for [Ru3Cl5(PP)3]+ (PP ) BINAP and (Ph2P)2-
C6H4).20 [Ru3Cl5(PPh3)6]+ appears to be the first struc-
turally characterized complexes of the type [Ru3Cl5(P)6]+
with monodentate phosphine ligands.
Z
d
2
calc, g cm-3
1.337
0.668
0.71073
0.99-27.61
43 015
We have tried to detect the reaction intermediates by
performing the protonation reaction in CD2Cl2 at low
temperature. Unfortunately, no intermediate could be
observed. To gain some insight into the protonation
reaction, we have also performed the protonation reac-
abs coeff, mm-1
radiation, Mo KR, Å
θ range, deg
no. of reflns collected
no. of ind reflns
no. of obsd reflns
25 880 (Rint ) 3.58%)
14 720 (I > 2σ(I))
2
tion with DOTf. The D NMR spectrum of norbornene
no. of params refined
final R indices (obs. data)
goodness of fit
456
isolated from the protonation reactions carried out in
R1 ) 6.31%, wR2 ) 16.36%
0.925
1.48
2
benzene or dichloromethane showed a D signal at 0.9
largest diff peak, e Å-3
largest diff hole, e Å-3
ppm, indicating that the deuterium is incorporated at
the endo position.21 The experimental result indicates
that the deuterium is transferred to the olefin from the
same side of the ruthenium.
Com m en ts on th e P ossible Rou te to th e F or m a -
tion of Nor bor n en e. There are many sites in [RuH-
(Cl)(PPh3)2(NBD)] that can be initially attacked by a
proton. For example, the proton could attack the hydride
or the chloride to give the dihydrogen complex [RuCl-
(H2)(NBD)(PPh3)2]+ (A) or the hydrochloride complex
[RuH(HCl)(NBD)(PPh3)2]+ (B), respectively (see Scheme
2). The proton could also attack the olefin ligand or the
metal center.
Protonation of ruthenium complexes [RuH(X)L4] (L4
) (dppe)2, X ) Cl, Br;13a,b L4 ) (dppp)2, X ) Cl;13c L4 )
(dcpe)2, X ) Cl;13d L4 ) (PPh3)(2,6-(Ph2PCH2)2C5H3N),
X ) Cl14) are known to give dihydrogen complexes of
the type [M(X)(H2)L4]+. Thus one might expect that
protonation of [RuH(Cl)(PPh3)2(NBD)] could also pro-
duce the dihydrogen complex [Ru(Cl)(H2)(PPh3)2(NBD)]+
-0.771
CDCl3, compound 5 displayed a singlet 31P signal at 40.2
ppm. The H NMR in CD2Cl2 showed broad signals in
1
the region 6.34-7.69 ppm. It is difficult to assign the
structure on the basis of the spectroscopic data. Thus a
single-crystal X-ray diffraction study on 5 was at-
tempted. Although a crystalline solid of 5 can be easily
obtained by slow diffusion of hexane to a CH2Cl2
solution of 5, it is difficult to solve the structure because
of the poor quality of the crystal and the disorder of the
triflate anion. Thus [Ru3Cl5(PPh3)6]OTf was converted
to [Ru3Cl5(PPh3)6]BPh4 by treatment with NaBPh4. The
X-ray diffraction study was then carried out with a
crystal of [Ru3Cl5(PPh3)6]BPh4.
Figure 1 shows the molecular structure of the cation
[Ru3Cl5(PPh3)6]+. Crystallographic details and selected
bond lengths and angles are given in Tables 1 and 2,
respectively. The three ruthenium atoms are in an
triangular arrangement and are linked by three µ2-
bridging chlorides and two face-caped chlorides. The
geometry around each ruthenium atom can be described
as a distorted octahedron with four chlorine atoms and
two cis PPh3 ligands. Similar complexes have been
(20) (a) Mashima, K.; Komura, N.; Yamagata, T.; Tani, K. Haga,
M. Inorg. Chem. 1997, 36, 2908. (b) Mashima, K.; Hino, T.; Takaya,
H. J . Chem. Soc., Dalton Trans. 1992, 2099. (c) Mashima, K.; Hino,
T.; Takaya, H. Tetrahedron Lett. 1991, 32, 3101.
(21) Laszlo, P.; Schleyer, P. von R. J . Am. Chem. Soc. 1964, 86, 1171.

4164 Organometallics, Vol. 20, No. 20, 2001
Liu et al.
Ta ble 2. Selected Bon d Dista n ces a n d An gles for [Ru 3Cl5(P P h 3)6]BP h 4‚2.5CH2Cl2
Bond Distances (Å)
Ru(1)-P(1)
Ru(1)-Cl(3)
Ru(2)-P(3)
Ru(2)-Cl(2)
Ru(3)-P(5)
Ru(3)-Cl(3)
Ru(1)-Ru(2)
2.33214(16)
2.4610(14)
2.3286(16)
2.4410(15)
2.3299(16)
2.4591(16)
3.3177(8)
Ru(1)-P(2)
2.3247(16)
2.4799(14)
2.3232(16)
2.5073(14)
2.3229(15)
2.4782(14)
3.3640(7)
Ru(1)-Cl(1)
Ru(1)-Cl(5)
Ru(2)-Cl(1)
Ru(2)-Cl(5)
Ru(3)-Cl(2)
Ru(3)-Cl(5)
Ru(2)-Ru(3)
2.4369(14)
Ru(1)-Cl(4)
Ru(2)-P(4)
Ru(2)-Cl(4)
Ru(3)-P(6)
Ru(3)-Cl(4)
Ru(1)-Ru(3)
2.4775(15)
2.4297(15)
2.4691(14)
2.4344(16)
2.4773(14)
3.3346(7)
Bond Angles (deg)
Ru(2)‚‚‚Ru(1)‚‚‚Ru(3)
59.87(1)
59.37(2)
104.29(5)
93.81(5)
94.88(5)
170.82(5)
153.63(5)
80.66(5)
79.08(5)
96.56(6)
103.21(5)
94.94(5)
170.21(5)
93.48(5)
80.03(5)
79.34(5)
77.80(4)
104.82(6)
94.06(6)
95.44(5)
171.37(6)
153.18(5)
80.26(5)
79.13(5)
85.96(5)
86.27(5)
83.96(4)
84.78(4)
85.52(4)
Ru(1)‚‚‚Ru(2)‚‚‚Ru(3)
P(1)-Ru(1)-P(2)
P(2)-Ru(1)-Cl(1)
P(2)-Ru(1)-Cl(3)
P(2)-Ru(1)-Cl(4)
P(2)-Ru(1)-Cl(5)
Cl(1)-Ru(1)-Cl(4)
Cl(3)-Ru(1)-Cl(4)
Cl(5)-Ru(1)-Cl(4)
Cl(1)-Ru(2)-Cl(2)
P(4)-Ru(2)-Cl(1)
P(4)-Ru(2)-Cl(2)
P(4)-Ru(2)-Cl(4)
P(4)-Ru(2)-Cl(5)
Cl(1)-Ru(2)-Cl(5)
Cl(2)-Ru(2)-Cl(5)
P(5)-Ru(3)-P(6)
P(6)-Ru(3)-Cl(2)
P(6)-Ru(3)-Cl(3)
P(6)-Ru(3)-Cl(5)
P(6)-Ru(3)-Cl(4)
Cl(2)-Ru(3)-Cl(4)
Cl(3)-Ru(3)-Cl(4)
Cl(5)-Ru(3)-Cl(4)
Ru(3)-Cl(2)-Ru(2)
Ru(3)-Cl(4)-Ru(1)
Ru(1)-Cl(4)-Ru(2)
Ru(2)-Cl(5)-Ru(1)
60.75(1)
95.37(6)
92.03(5)
105.39(5)
168.52(5)
92.15(5)
80.44(5)
79.04(5)
78.16(5)
154.58(5)
93.71(5)
101.82(6)
92.41(5)
169.50(5)
80.97(5)
80.30(5)
95.72(6)
92.27(6)
104.80(6)
167.87(5)
91.16(5)
80.04(5)
79.11(5)
78.19(4)
86.31(5)
85.45(4)
83.40(4)
84.24(4)
Ru(1)‚‚‚Ru(3)‚‚‚Ru(2)
P(1)-Ru(1)-Cl(1)
P(1)-Ru(1)-Cl(3)
P(1)-Ru(1)-Cl(4)
P(1)-Ru(1)-Cl(5)
Cl(1)-Ru(1)-Cl(3)
Cl(1)-Ru(1)-Cl(5)
Cl(3)-Ru(1)-Cl(5)
P(4)-Ru(2)-P(3)
P(3)-Ru(2)-Cl(1)
P(3)-Ru(2)-Cl(2)
P(3)-Ru(2)-Cl(4)
P(3)-Ru(2)-Cl(5)
Cl(1)-Ru(2)-Cl(4)
Cl(2)-Ru(2)-Cl(4)
Cl(5)-Ru(2)-Cl(4)
P(5)-Ru(3)-Cl(2)
P(5)-Ru(3)-Cl(3)
P(5)-Ru(3)-Cl(5)
P(5)-Ru(3)-Cl(4)
Cl(2)-Ru(3)-Cl(3)
Cl(2)-Ru(3)-Cl(5)
Cl(3)-Ru(3)-Cl(5)
Ru(2)-Cl(1)-Ru(1)
Ru(3)-Cl(3)-Ru(1)
Ru(3)-Cl(4)-Ru(2)
Ru(2)-Cl(5)-Ru(3)
Ru(3)-Cl(5)-Ru(1)
(A). It has been previously reported that the dihydrogen
complex [Mo(H2)(CO)3(η4-NBD)] would undergo a hy-
drogen transfer reaction to give nortricyclene (6) (eq
1).7a Thus, hydrogenation through intermediate A would
that protonation of chloride indeed occurred in the
reaction. Involvement of hydrochloride complex B in the
formation of norbornene is also consistent with the
deuterium labeling experiment where protonation of
[RuH(Cl)(PPh3)2(NBD)] with DOTf produced deuterated
norbornene in which the deuterium is at the endo
position. Protonation of halide ligands has been ob-
served in the protonation reactions of chloro hydride
complexes such as [OsH2Cl2(P(i-Pr)3)2],15a [PtHCl(P-
(t-Bu)2Me)2],12 and [OsH2Cl(NO)(P(i-Pr)3)2].15b Although
well-characterized hydrohalide complexes are still rare,22
well-characterized alkylhalide complexes [M(XR)Ln]23
and halide complexes with intra- or intermolecular
MX‚‚‚H interaction24 are numerous.
more likely produce nortricyclene (6) (or a mixture of
nortricyclene and norbornene) through intermediate C
rather than norbornene (see Scheme 2). In reality, no
nortricyclene (6) was detected by NMR spectroscopy in
our experiment. We also found no experimental evidence
for the formation of the dihydrogen intermediate A.
Thus, formation of norbornene in the protonation reac-
tion of [RuH(Cl)(PPh3)2(NBD)] is unlikely related to the
dihydrogen complex [Ru(Cl)(H2)(PPh3)2(NBD)]+, al-
though such a possibility cannot be confidently elimi-
nated.
There is a possibility that formation of norbornene
in the protonation reaction is related to the protonation
of the chloride ligand (path 1 of Scheme 2). Protonation
of the chloride would give the hydrochloride complex
[RuH(HCl)(NBD)(PPh3)2]+ (B) which can then undergo
a hydrogen transfer reaction to give intermediate D.
Intermediate D can undergo reductive elimination to
produce norbornene. Formation of [RuH(OTf)(PPh3)2-
(NBD)] from the protonation reaction strongly suggests
To prove that protonation of the chloride is likely one
of the initial events in the protonation reaction, we have
(22) (a) Fischer, E. O.; Walz, S.; Kreis, G.; Kreibl, F. R. Chem. Ber.
1977, 110, 1651. (b) Mazej, Z.; Borrmann, H.; Lutar, K.; Zemva, B.
Inorg. Chem. 1998, 37, 5912.
(23) See for example: (a) Huhmann-Vincent, J .; Scott, B. L.; Kubas,
G. J . Inorg. Chem. 1999, 38, 115. (b) Huang, D.; Huffman, J . C.;
Bollinger, J . C.; Eisenstein, O.; Caulton, K. G. J . Am. Chem. Soc. 1997,
119, 7398. (c) Butts, M. D.; Scott, B. L.; Kubas, G. J . J . Am. Chem.
Soc. 1996, 118, 11831, and references therein. (d) Kulawiec, R. J .;
Crabtree, R. H. Coord. Chem. Rev. 1990, 99, 89, and references therein.
(24) See for example: (a) Roe, D. C.; Marshall, W. J .; Davidson, F.;
Soper, P. D.; Grushin, V. V. Organometallics 2000, 19, 4575, and
references therein. (b) J asim, N. A.; Perutz, R. N. J . Am. Chem. Soc.
2000, 122, 8685. (c) Lee, D. H.; Kwon, H. J .; Patel. B. P.; Liable-Sands,
L. M.; Rheingold, A. L.; Crabtree, R. H. Organometallics 1999, 18, 1615.
(d) Esteruelas, M. A.; Oliva´n, M.; On˜ate, E.; Ruiz, N.; Tajada, M.
Organometallics 1999, 18, 2953. (e) Hampton, C. R. S. M.; Butler, I.
R.; Cullen, W. R.; J ames, B. R.; Charland, J . P.; Simpson, J . Inorg.
Chem. 1992, 31, 5509. (f) Sellmann, D.; Barth, I.; Moll, M. Inorg. Chem.
1990, 29, 176. (g) Richmond, T. G. Coord. Chem. Rev. 1990, 105, 221.

Reactions of [MH(Cl)(PPh3)2(norbornadiene)]
Organometallics, Vol. 20, No. 20, 2001 4165
performed the protonation of [RuH(Cl)(PPh3)2(NBD)]
with HOTf in the presence of CH3CN. It is expected that
[RuH(CH3CN)(PPh3)2(NBD)]+ would be produced if
intermediate [RuH(HCl)(PPh3)2(NBD)]+ (B) was formed
due to protonation of the chloride ligand and that [RuCl-
(CH3CN)(PPh3)2(NBD)]+ would be produced if interme-
diate [Ru(Cl)(H2)(PPh3)2(NBD)]+ (A) is formed due to
protonation of the hydride ligand. In C6D6 or CD2Cl2 in
the presence of CH3CN, [RuH(Cl)(PPh3)2(NBD)] reacted
rapidly with HOTf to give [RuH(CH3CN)(PPh3)2(NBD)]-
OTf (7) as the only product (eq 2). A control experiment
P r oton a tion of [OsH(Cl)(P P h 3)2(NBD)]. With the
hope to detect the reaction intermediate, we have
studied the protonation reaction of [OsH(Cl)(PPh3)2-
(NBD)] (8). Protonation of [OsH(Cl)(PPh3)2(NBD)] (8)
with a limiting amount of HOTf in benzene or dichloro-
methane only produced [OsH(OTf)(PPh3)2(NBD)] (9)19
(eq 3). If excess of HOTf was used, a complicated
mixture of phosphorus-containing species was produced.
Neither norbornene or nortricyclene was observed in the
protonation reactions.
Th eor etica l Stu d y. Several interesting questions
arise from the experimental results. (i) We have pro-
posed that the intermediate [RuH(HCl)(PPh3)2(NBD)]+
(B) is possibly involved in the formation of norbornene
in the protonation of 1 (Scheme 2). Unfortunately, we
have not been able to detect the intermediate. One may
ask whether intermediate B is a reasonable species and
whether proton transfer from the Ru-H and coordi-
nated HCl to the NBD ligand in B is kinetically feasible.
(ii) Protonation of [RuH(X)P4] (P ) phosphines) usually
leads to the formation of the dihydrogen complexes [Ru-
(X)(H2)P4]+. Thus one might expect that protonation of
[RuH(Cl)(PPh3)2(NBD)] could also produce the dihydro-
gen complex [Ru(Cl)(H2)(PPh3)2(NBD)]+ (A). However,
the dihydrogen complex A was not observed experimen-
tally in the protonation of [RuH(Cl)(PPh3)2(NBD)]. Ap-
parently the dihydrogen complex A is also not involved
in the hydrogenation of NBD. One may ask why
hydrogenation of NBD could not proceed through the
dihydrogen intermediate A. (iii) Protonation of [RuH-
(Cl)(PPh3)2(NBD)] with HOTf led to the formation of
[RuH(OTf)(PPh3)2(NBD)] along with norbornene. How-
ever, protonation of [OsH(Cl)(PPh3)2(NBD)] with HOTf
only produced [OsH(OTf)(PPh3)2(NBD)]. One may ask
why the protonation products for the ruthenium system
are so different from those of the osmium system.
To answer these questions, theoretical calculations
based on the B3LYP density functional theory have been
carried out to examine the structural and energetic
aspects of the possible reaction pathways involving the
model hydrochloride complex [RuH(HCl)(PH3)2(NBD)]+
(10Ru ) and the model dihydrogen species [Ru(Cl)(H2)-
(PH3)2(NBD)]+ (10Ru ′).
Figure 2 shows the two possible reaction pathways,
which start from 10R u (path 1) and 10R u ′ (path 2),
respectively, together with the calculated free energies
for the reactants, intermediates, transition states, and
the assumed products (12Ru and 12Ru ′). The reaction
energies are also given in parentheses. The calculated
reaction energies and free energies give consistent
trends in the relative stabilities among the different
species. Our calculations are based on the gas-phase
model. The results are used to simulate the reactions
in solution. It is therefore more appropriate to use the
calculated free energies, which consider the entropy
effect as well as the thermal/zero-point energy correc-
tions, in discussing the relevant energetics. Path 1 starts
from 10Ru with the first hydrogen transfer from Ha to
shows that [RuH(Cl)(PPh3)2(NBD)] is unreactive toward
CH3CN alone. The result strongly suggests that proto-
nation of chloride could occur readily. Exclusive forma-
tion of [RuCl(CH3CN)(PPh3)2(NBD)]+ (rather than [RuH-
(CH3CN)(PPh3)2(NBD)]+) in the protonation of [RuH(Cl)-
(PPh3)2(NBD)] in the presence of CH3CN may also imply
that protonation of the chloride ligand is kinetically
more favorable than protonation of the hydride ligand.
Although it could not be completely excluded, forma-
tion of norbornene is also unlikely related to direct
protonation of the NBD ligand or the ruthenium center
in [RuH(Cl)(PPh3)2(NBD)] (1). Direct protonation of the
NBD ligand in 1 would initially produce both intermedi-
ates C and D, from which a mixture of nortricyclene
and norbornene would be produced (see Scheme 2).
However, only norbornene could be detected experimen-
tally in the protonation reaction. In addition, in the
protonation of complexes such as [Ni(COD)2],25 [Fe(CO)3-
(η4-cycloheptatrienone)],26 [Mo(MeCtCH)2(dppe)2],27 and
[VCp2(MeCtCMe)],28 where the coordinated olefin or
alkyne ligands are attacked directly by protons,29 the
protons are added to the olefin or alkyne ligands from
the “solvent side”. Thus deuteration may occur at the
exo position of norbornene if norbornene was produced
through direct protonation of the NBD ligand in 1.
However, the deuterium is incorporated only at the endo
position of norbornene in the protonation of 1 with
DOTf. Initial protonation of the ruthenium center in 1
to give dihydride species [RuH2(Cl)(PPh3)2(NBD)]+ fol-
lowed by proton transfer would also produce both
intermediates C and D, which would eventually give a
mixture of nortricyclene and norbornene. Since only
norbornene is produced in the protonation reaction, it
is therefore unlikely that such a process is involved in
the formation of norbornene. In addition, formation of
the dihydride species [RuH2(Cl)(PPh3)2(NBD)]+ is not
supported by theoretical studies (see discussion later).
(25) Åkermark, B.; Martin, J . Nystro¨m, J . E.; Stro¨mberg, S.;
Svensson, M.; Zetterberg, K.; Zuber, M. Organometallics 1998, 17,
5367.
(26) Hunt, D. F.; Farrant, G. C.; Rodeheaver, G. T. J . Organomet.
Chem. 1972, 38, 349.
(27) Henderson, R. A.; Oglieve, K. E.; Salisbury, P. J . Chem. Soc.,
Dalton Trans. 1995, 2479.
(28) Henderson, R. A.; Lowe, D. J .; Salisbury, P. J . Organomet.
Chem. 1995, 489, C22.
(29) For additional examples of direct protonation of olefin and
alkyne ligands, see: Henderson, R. A. Angew. Chem., Int. Ed. Engl.
1996, 35, 946, and references therein.

4166 Organometallics, Vol. 20, No. 20, 2001
Liu et al.
F igu r e 2. Schematic illustration of the two studied reaction pathways together with calculated relative free energies
(kcal/mol) and reaction energies (kcal/mol, in parentheses) for species involved in the reaction.
form intermediate 11Ru . Then the second hydrogen
transfer from Hb completes the hydrogenation and gives
a coordinated norbornene complex 12Ru . Path 2 starts
from 10R u ′ with the hydrogen transfer from one
hydrogen atom of the dihydrogen ligand to form inter-
mediate 11Ru ′. The second hydrogen transfer forms a
precursor complex 12Ru ′, which can give a nortricyclene
by reductive elimination.
sistent with the experimental observation that the NBD
ligand of [RuH(Cl)(PPh3)2(NBD)] is hydrogenated to
produce norbornene after the protonation of the hydride
complex. In addition, these results also support the
proposition that the chloride is indeed assisting the
hydrogenation process by positioning a hydrogen at an
approximate position to the olefin ligand through a HCl
ligand.
The reaction from the dihydrogen complex 10Ru ′
(path 2) overcomes a barrier of 9.3 kcal/mol through
TS1′, forming the relatively unstable intermediate
(11Ru ′). Climbing another barrier of 8.6 kcal/mol for
the second hydrogen transfer, one gets the complex
12Ru ′ (a precursor to nortricyclene). Since the overall
reaction from 10Ru ′ to 12Ru ′ is endothermic, formation
of 12Ru ′ from 10Ru ′ is unlikely. The finding is consis-
tent with the experimental result that no nortricylene
was produced in the protonation of [RuH(Cl)(PPh3)2-
(NBD)]. In addition, it is noted that 11Ru ′ could not
undergo reductive elimination to give norbornene be-
cause the alkyl and the hydride ligands are not cis to
each other. Thus it is unlikely that norbornene is formed
from the dihydrogen intermediate [Ru(Cl)(H2)(PPh3)2-
(NBD)]+ in the protonation of [RuH(Cl)(PPh3)2(NBD)].
From the relative free energies (Figure 2), it is
interesting to see that the hydrochloride complex 10Ru
is only slightly less stable than the dihydrogen complex
10Ru ′, indicating that intermediate [RuH(HCl)(PPh3)2-
(NBD)]+ (B) is indeed a reasonable species. For the
reaction starting from 10Ru (path 1), the barrier of the
first hydrogen transfer is slightly higher (10.1 kcal/mol)
when compared to that of path 2. The second hydrogen
transfer is almost barrierless. The overall reaction of
path 1 is exothermic. Clearly, the reaction from the
hydrochloride complex (path 1) is both thermodynami-
cally and kinetically favorable. These results are con-
One of the reviewers was concerned that the proposed
intermediates 11Ru and 11Ru ′ are questionable be-
cause of no known examples of seven-coordinate
Ru(IV) complexes featuring agostic interactions. On the
basis of the potential energy profiles given in Figure 2,
we can see that these intermediates are very reactive
and easily converted into 12Ru for 11Ru and 10Ru ′
for 11Ru ′. These results are consistent with the fact that
seven-coordinate Ru(IV) complexes featuring agostic
interactions have not yet been characterized. It should
be noted that seven-coordinate Ru(IV) complexes are not
unusual, as several of them have been characterized by
X-ray diffraction.30 The formally seven-coordinate Os-
(IV) complex [OsH2(η3-C6H9)(PiPr3)2]+ with an agostic
interaction has been recently reported.31 Therefore, we
feel reasonable to propose 11Ru and 11Ru ′ as very
reactive intermediates in the reaction routes. The
calculated Ru‚‚‚H-C distance (1.817 Å) in 11Ru ′ was
also considered as unreasonably short. This could be
because there is still some sort of attraction between
the hydride ligand and the agostic hydrogen in the
intermediate. As the intermediate is very unstable, such
an unusual structural feature is possible.
(30) See for example: (a) Given, K. W.; Mattson, B. M.; Pignolet, L.
H. Inorg. Chem. 1976, 15, 3152. (b) Mattson, B. M.; Pignolet, L. H.
Inorg. Chem. 1977, 16, 488.
(31) Castillo, A.; Esteruelas, M. A.; On˜ate, E.; Ruiz, N. J . Am. Chem.
Soc. 1997, 119, 9691.

Reactions of [MH(Cl)(PPh3)2(norbornadiene)]
Organometallics, Vol. 20, No. 20, 2001 4167
Calculations on other intermediate structures, such
as nonagostic species with 16 electrons and dihydride
structure, were not successful. Starting with a structure
having the agostic hydrogen atom away from Ru at a
distance of 2.5 Å, the optimizations always lead to 11Ru
and 11Ru ′. By fixing the distance at 2.5 Å, the partially
optimized structures are calculated to be ca. 7 kcal/mol
higher in energy than the fully optimized intermediates.
These partially optimized structures experience ex-
tremely unfavorable metal-carbon interactions because
of the geometric requirement with the norbornenyl
ligand. Although many 16-electron Ru complexes are
known, these complexes are normally five-coordinate
and adopt a square-pyramidal structure having one
vacant ligand site. Instead of having 16-electron inter-
mediates without agostic interactions, the strong ten-
dency to have the agostic interactions with an 18-
electron configuration in the currently studied inter-
mediates is apparently due to the different ligand
number as well as the different ligand environment.
Therefore a reductive elimination through the nonagos-
tic species with 16 electrons would require a higher
activation energy. An attempt to find a concerted
process by simultaneously transferring the two hydro-
gen atoms to one of the two olefin bonds in the NBD
ligand was also not successful.
One might also consider the possibility of the rear-
rangement from 11Ru ′ (derived from protonation of
hydride) to 11Ru (derived from protonation of chloride),
which gives the reaction outcome independent of the
initial protonation sites. However, such a rearrange-
ment is unlikely on the basis of the following consider-
ations. 11Ru ′ is quite unstable relative to 11Ru and
10Ru ′. The conversion of 11Ru ′ back to 10Ru ′ through
TS1′ has a very low barrier (only 1.5 kcal/mol). In
contrast, the rearrangement from 11R u ′ to 11R u
involves drastic movement of ligands. An appreciable
activation energy from 11Ru ′ to 11Ru would prevent
such a rearrangement from occurring.
Another possible pathway starting from hydrochloride
complex 10Ru is that the hydride (Hb) transfer occurs
prior to the hydrogen from the hydrochloride ligand. The
intermediate from such a pathway is calculated to be
13.0 kcal/mol higher in energy than 10Ru . It is expected
that the corresponding transition state has an even
higher energy. Therefore, this possible pathway can be
eliminated. As mentioned previously, direct protonation
at the ruthenium center of 1 would give dihydride
species [RuH2(Cl)(NBD)(PPh3)2]+, which may also lead
to the formation of norbornene. To test this possibility,
the structure of the model complex [RuH2(Cl)(PH3)2-
(NBD)]+ was optimized. However, the optimized struc-
ture turns to 10Ru or 10Ru ′. The dihydride complex
[RuH2(Cl)(NBD)(PH3)2]+ was not found to be a transi-
tion state in the conversion of 10Ru to 12Ru either.
This result suggests that [RuH2(Cl)(PH3)2(NBD)]+ is
unlikely to be involved in the formation of norbornene.
F igu r e 3. Optimized structures with selected structural
parameters (and relative stability). The hydrogen atoms,
which are not directly involved in the hydrogenation, have
been omitted for the purpose of clarity.
ates 11Ru and 11Ru ′ can be described as pentagonal-
bipyramidal (PB) in which the olefin and one of the
phosphine ligands form the axle of the PB structure. In
11Ru , the chloride and the agostic ligands can be
viewed as trans to the hydride ligand on the equatorial
plane of the PB structure. Such an arrangement pro-
vides an optimal coordination because the two weaker
bonds (Ru-Cl and Ru-agostic) occupy the coordination
sites trans to the strong trans-influence hydride ligand.
The stability of intermediate 11Ru suggests that the
Ru-H and Ru-C σ bonds prefer to be cis to each other.
Indeed, the Ru-H and Ru-C σ bonds on the equatorial
plane of the PB structure in 11Ru are shorter than the
corresponding ones in 11Ru ′. The high stability of the
norbornene complex (12Ru ) is related to its octahedral
arrangement of all the ligands. The precursor complex
12Ru ′ is highly strained because of the presence of three
four-membered rings in the structure.
Figure 3 shows the calculated structures with selected
structural parameters of those species involved in the
studied reactions. The hydrochloride complex (10Ru )
has a very long Ru-Cl distance (2.838 Å) due to the
trans influence of the hydride ligand and the low donor
ability of the HCl ligand. The dihydrogen complex 10Ru ′
shows a short H-H distance (0.834 Å). Both intermedi-
While the protonation of [RuH(Cl)(PPh3)2(NBD)] with
HOTf leads to the formation of [RuH(OTf)(PPh3)2(NBD)]

4168 Organometallics, Vol. 20, No. 20, 2001
Liu et al.
300 spectrometer (300 MHz). 1H and 13C NMR chemical shifts
are relative to TMS, and 31P NMR chemical shifts relative to
85% H3PO4.
along with norbornene, protonation of [OsH(Cl)(PPh3)2-
(NBD)] with HOTf gives only the substitution product
[OsH(OTf)(PPh3)2(NBD)]. There are two possible expla-
nations for the experimental observation. The corre-
sponding reaction from the analogous hydrochloride
complex 10Os might have a much higher reaction
barrier. Calculations of the corresponding reaction give
a free energy barrier of 8.4 kcal/mol and do not support
this explanation. However, the calculation results show
that the norbornene complex 12Os is thermodynami-
cally less stable by 2.1 kcal/mol when compared to 10Os.
Therefore, the second possible explanation can be
related to the fact that the competing substitution (Cl-
by OTf-) reaction in [OsH(Cl)(PPh3)2(NBD)] could be
more favorable. Indeed the substitution reaction free
energy is calculated to be -5.5 kcal/mol, which is
thermodynamically much more favorable than the cor-
responding hydrogenation reaction giving 12Os. The
hydrogenation free energy is 2.1 kcal/mol, which is 7.6
kcal/mol higher than the substitution reaction. For
[RuH(Cl)(PPh3)2(NBD)], the substitution reaction free
energy (-8.2 kcal/mol) is, however, calculated to be
slightly higher by 1.6 kcal/mol than the hydrogenation
free energy (-9.8 kcal/mol). These results are in agree-
ment with the experimental observation that the Os
complex involves only the substitution reaction, while
the Ru complex undergoes the hydrogenation reaction
as well as the substitution reaction. On the basis of the
results of our calculations, a plausible explanation for
the different reactivities of the Os and Ru complexes
can be provided here. The third-row transition metal
has more diffuse d orbitals, leading to a stronger metal-
olefin interaction. Osmium-olefin complexes are ex-
pected to be more stable when compared to the corre-
sponding ruthenium-olefin complexes, and therefore,
the Os-NBD bonds remain intact in the reactions.
Su m m a r y a n d Con clu sion . [RuH(Cl)(PPh3)2(NBD)]
in C6D6 reacted with HOTf to give [RuH(OTf)(PPh3)2-
(NBD)], norbornene, and [RuCl2(PPh3)2]2. In dichloro-
methane, [RuH(Cl)(PPh3)2(NBD)] reacted with HOTf to
give [RuH(OTf)(PPh3)2(NBD)], norbornene, and the tri-
metallic complex [Ru3Cl5(PPh3)6]OTf. In contrast, pro-
tonation of [OsH(Cl)(PPh3)2(NBD)] in C6D6 or CD2Cl2
with HOTf gave only [OsH(OTf)(PPh3)2(NBD)]. The fact
that norbornene was not produced in the protonation
of [OsH(Cl)(PPh3)2(NBD)] can be attributed to the
stronger osmium-olefin interaction. In the protonation
of [RuH(Cl)(PPh3)2(NBD)], the norbornene is likely
produced through the intermediate [RuH(HCl)(PPh3)2-
(NBD)]+. The involvement of [RuH(HCl)(PPh3)2(NBD)]+
in the formation of norbornene is supported by theoreti-
cal calculations based on the B3LYP density functional
theory.
P r oton a tion of [Ru H(Cl)(P P h 3)2(NBD)] w ith HOTf in
C6D6. To an NMR tube charged with [RuH(Cl)(PPh3)2(NBD)]
(20 mg, 0.027 mmol) and C6D6 (0.5 mL) was added 0.015 mL
of C6D6 solution of HOTf (HOTf/C6D6 ) 1:8, 0.019 mmol HOTf)
through a microsyringe. The solution was allowed to stand for
1
1 h, and then NMR spectra were collected. H NMR (300.13
MHz, C6D6): δ -13.47 (t, J (PH) ) 22.5 Hz, [RuH(OTf)(PPh3)2-
(NBD)]), -8.74 (t, J (PH) ) 24.0 Hz, [RuH(Cl)(PPh3)2(NBD)]),
1.05-1.74 (m, CH2 of norbornene, [RuH(Cl)(PPh3)2(NBD)] and
[RuH(OTf)(PPh3)2(NBD)]), 2.91 (s, bridge-head CH of nor-
bornene), 3.33-4.60 (m, bridge-head CH and dCH of [RuH-
(Cl)(PPh3)2(NBD)] and [RuH(OTf)(PPh3)2(NBD)]), 6.12 (s, d
CH of norbornene), 7.04-7.74 (m, PPh3). 31P{H} NMR (121.50
MHz, C6D6): δ 39.8 (s, [RuH(Cl)(PPh3)2(NBD)]), 41.5 (s, [RuH-
(OTf)(PPh3)2(NBD)]), 52.6 (s) and 59.7 (broad, [RuCl2(PPh3)2]2).
The ratio of norbornene to [RuH(OTf)(PPh3)2(NBD)] was
determined to be 1:2.1 on the basis of the integration of the
norbornene olefinic 1H signal at 6.12 ppm and the hydride
signal of [RuH(OTf)(PPh3)2(NBD)] at -13.47 ppm. The 1H
NMR and 31P NMR spectra showed no appreciable change
after the solution was allowed to stand for 19 h. The volatile
portion of the reaction mixture can be separated by vacuum
transfer. A 1H NMR spectrum of the vacuum-transferred
solution shows that norbornene is the only volatile organic
product formed in the reaction.
P r oton a tion of [Ru H(Cl)(P P h 3)2(NBD)] w ith DOTf in
C6H6. The procedure was similar to that described above
except that DOTf and C6H6 were used instead. The volatile
portion of the reaction mixture was separated by vacuum
transfer. The separated organic solution was treated with
Proton Sponge and then was subjected to vacuum transfer
again. The 2D NMR spectrum (61.25 MHz) of the resulting
solution showed a singlet at 0.89 ppm.
P r oton a tion of [Ru H(Cl)(P P h 3)2(NBD)] w ith HOTf in
CD2Cl2. To an NMR tube charged with [RuH(Cl)(PPh3)2(NBD)]
(20 mg, 0.027 mmol) and CD2Cl2 (0.5 mL) was added 0.015
mL of CD2Cl2 solution of HOTf (HOTf/CD2Cl2 ) 1:8, 0.019
mmol) through a microsyringe. The solution was allowed to
1
stand for 5 h, and then NMR spectra were collected. H NMR
(300.13 MHz, CD2Cl2): δ -13.8 (br, [RuH(OTf)(PPh3)2(NBD)]),
-9.46 (brt, J (PH) ) 24 Hz, [RuH(Cl)(PPh3)2(NBD)]), 0.88-1.70
(m, CH2 of norbornene, [RuH(Cl)(PPh3)2(NBD)] and [RuH-
(OTf)(PPh3)2(NBD)]), 2.80 (s, bridge-head CH of norbornene),
3.33-4.60 (m, bridge-head CH and dCH of [RuH(Cl)(PPh3)2-
(NBD)] and [RuH(OTf)(PPh3)2(NBD)]), 6.00 (s, dCH of nor-
bornene), 7.01-7.70 (m, PPh3). 31P{1H} NMR (121.50 MHz,
CD2Cl2): δ 39.9 (s, [RuH(Cl)(PPh3)2(NBD)]), 40.3 (s, [Ru3Cl5-
(PPh3)6]OTf), 41.6 (br, [RuH(OTf)(PPh3)2(NBD)]). The ratio of
norbornene to [RuH(OTf)(PPh3)2(NBD)] was determined to be
1
1:1.8 based on the integration of the norbornene olefinic H
signal at 6.00 ppm and the hydride signal of [RuH(OTf)(PPh3)2-
(NBD)] at -13.8 ppm. The 1H NMR and 31P NMR spectra
showed no appreciable change after the solution was allowed
to stand for 19 h. The volatile portion of the reaction mixture
can be separated by vacuum transfer. A 1H NMR spectrum of
the vacuum-transferred solution shows that norbornene is the
only volatile organic product formed in the reaction.
P r oton a tion of [Ru H(Cl)(P P h 3)2(NBD)] w ith DOTf in
CH2Cl2. The procedure was similar to that described above
except that DOTf and CH2Cl2 were used instead. The volatile
portion of the reaction mixture was separated by vacuum
transfer. The separated organic solution was treated with
Proton Sponge and then was subjected to vacuum transfer
again. The 2D NMR spectrum (61.25 MHz) of the resulting
solution showed a singlet at 0.93 ppm.
Exp er im en ta l Section
All manipulations were carried out under nitrogen atmo-
sphere using standard Schlenk techniques. Solvents were
distilled under nitrogen from sodium-benzophenone (hexane,
ether, THF) or calcium hydride (CH2Cl2). The starting materi-
als [RuH(Cl)(PPh3)2(NBD)]16 and [OsH(Cl)(PPh3)2(NBD)]19
were prepared according to literature methods. All other
reagents were used as purchased from Aldrich Chemical Co.
Microanalyses were performed by M-H-W Laboratories (Phoe-
nix, Az). 1H, 13C{1H}, and 31P{1H} NMR spectra were collected
on a J EOL EX-400 spectrometer (400 MHz) or a Bruker ARX-
[Ru 3Cl5(P P h 3)6]OTf. A mixture of [RuH(Cl)(PPh3)2(NBD)]
(0.84 g, 1.11 mmol) and HOTf (0.4 mL, 4.5 mmol) in dichloro-
methane (20 mL) and water (20 mL) was stirred for 72 h. The

Reactions of [MH(Cl)(PPh3)2(norbornadiene)]
Organometallics, Vol. 20, No. 20, 2001 4169
aqueous layer was then removed with a syringe. The dichlo-
romethane layer was washed with 30 mL of water. The solvent
was then removed completely under vacuum to give a brown
solid, 20 mL of diethyl ether was added, and the mixture was
stirred for 20 min. The brown solid was collected on a filter
frit, washed with diethyl ether (3 × 10 mL), and dried under
vacuum. Yield: 0.72 g, 88.3%. Anal. Calcd for C109H90Cl5F3O3P6-
SRu3: C, 59.42; H, 4.12. Found: C, 59.24; H, 4.40. 1H NMR
(300.13 MHz, CDCl3): δ 6.34-7.69 (m, broad, PPh3). 31P{1H}
NMR (121.49 MHz, CDCl3): δ 40.2 (s).
[Ru 3Cl5(P P h 3)6]BP h 4. [Ru3Cl5(PPh3)6]OTf (0.5 g, 0.23 mmol)
and NaBPh4 (0.5 g, 1.46 mmol) in methanol (40 mL) were
stirred for 1 h to give a brown solid, which was collected on a
filter frit, washed with methanol (3 × 10 mL), and dried under
vacuum. Yield: 0.48 g, 88.9%. Anal. Calcd for C132H110BCl5P6-
Ru3: C, 66.80; H, 4.67. Found: C, 66.90; H, 4.70. 1H NMR
(300.13 MHz, CD2Cl2): δ 6.3-7.7 (m, broad, PPh3). 31P{1H}
NMR (121.49 MHz, CD2Cl2): δ 40.3 (s).
area detector using graphite-monochromated Mo KR radiation
(λ ) 0.71073 Å). Intensity data were corrected for SADABS
(Siemens Area Detector Absorption)32 (from 0.757 to 1 on I).
The structure was solved by direct methods and refined by
full matrix least-squares on F2 using the Bruker SHELXTL
(Version 5.10)33 program package. Non-hydrogen atoms of the
cation were refined anisotropically. The phenyl rings of the
-
BPh4 anion were treated as rigid groups and refined with
isotropic parameters. The dichloromethane solvent molecules
were disordered and refined isotropically with partial oc-
cupancy factors using fixed C-Cl distances restraints without
addition of H atoms. The remaining H atoms were introduced
at calculated positions and refined via a riding model. Further
details are given in Table 1.
Com p u ta tion a l Deta ils. In the calculations, the PPh3
ligands have been modeled using PH3 groups. Geometry
optimizations and frequency calculations have been performed
for all species (reactants, precursors, intermediates, transition
states, and assumed products) involved in the reactions using
the Gaussian 98 program34 installed on Pentium III personal
computers with Linux (Redhat) operating systems. All calcula-
tions have been carried out at the B3LYP level of density
functional theory. The LANL2DZ effective core potentials and
basis sets35 were used to describe Ru, Os, P, and Cl, while the
standard 6-31G basis set was used for C and H atoms.
Polarization functions36 were added for Cl (ê(d) ) 0.514) and
hydrogens (ê(p) ) 1.1) involved in the transfer processes.
P r oton a tion of [Ru H(Cl)(P P h 3)2(NBD)] w ith DOTf in
CD2Cl2 in th e P r esen ce of CD3CN. To an NMR tube charged
with [RuH(Cl)(PPh3)2(NBD)] (20 mg), CD2Cl2 (0.7 mL), and
CD3CN (50 µL) was added DOTf (10 µL) through a microsy-
ringe. The 1H and 31P(1H} NMR spectra of the reaction mixture
1
showed only the signals of [RuH(CH3CN)(PPh3)2(NBD)]+. H
NMR (300.13 MHz, CD2Cl2): δ -8.74 (t, J (PH) ) 22.4 Hz, 1
H, RuH), 0.78 (s, 2 H, CH2), 3.04 (s, 2 H, dCH), 3.42 (s, 1 H,
CH), 3.56 (s, 1 H, CH), 3.63 (s, 2 H, dCH), 6.95-7.44 (m, PPh3).
31P{1H} NMR (121.49 MHz, CD2Cl2): δ 45.2 (s).
[Ru H(CH3CN)(P P h 3)2(NBD)]BP h 4. CH3CN (1.0 mL) was
added to a CH2Cl2 (30 mL) solution of [RuH(OTf)(PPh3)2(NBD)]
(1.41 g, 1.62 mmol). The solvent was removed completely under
vacuum. MeOH (40 mL) was added to redissolve the solid.
NaBPh4 (0.50 g, 2.34 mmol) in MeOH (10 mL) was added. A
large amount of white precipitate was formed. The white solid
was collected on a filter frit, washed with water, and dried
Ack n ow led gm en t. The authors acknowledge finan-
cial support from the Hong Kong Research Grants
Council.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal-
lographic details, bond distances and angles, atomic coordi-
nates and equivalent isotropic displace coefficients, and aniso-
tropic displacement coefficients for [Ru3Cl5(PPh3)6]BPh4. This
material is available free of charge via the Internet at
http://pubs.acs.org.
under vacuum. Yield: 1.49 g, 85.2%. Anal. Calcd for C69H62
-
BNP2Ru: C, 76.80; H, 5.80; N, 1.30. Found: C, 76.78; H, 5.37;
1
N, 1.27. H NMR (300.13 MHz, CD2Cl2): δ -8.59 (t, J (PH) )
22.2 Hz, 1 H, RuH), 1.09 (s, 2 H, CH2), 1.82 (s, 3 H, CH3CN),
3.23 (s, 2 H, dCH), 3.46 (s, 1 H, CH), 3.49 (s, 1 H, CH), 3.61
(s, 2 H, dCH), 6.87-7.45 (m, 50 H, BPh4, PPh3). 31P{1H} NMR
(121.49 MHz, CD2Cl2): δ 45.2 (s).
OM010029R
P r oton a tion of [OsH(Cl)(P P h 3)2(NBD)] w ith HOTf in
C6D6. To an NMR tube charged with [OsH(Cl)(PPh3)2(NBD)]
(20 mg, 0.024 mmol) and C6D6 (0.5 mL) was added HOTf (5
µL, 0.057 mmol) through a microsyringe. The solution was
allowed to stand for 1 h, and then NMR spectra were collected.
The NMR spectra showed signals of [OsH(OTf)(PPh3)2(NBD)].
1H NMR (300.13M Hz, C6D6): δ -17.57 (t, J (PH) ) 21.0 Hz,
1 H OsH), 0.68 (s, 2 H, CH2), 3.46 (s, 1 H, bridgehead CH),
3.63 (s, 2 H, dCH), 4.05 (s, 2 H, dCH), 4.86 (s, 1 H, bridgehead
CH), 6.5-7.9 (m, PPh3). 31P{1H} NMR (121.50 MHz, C6D6): δ
12.6 (s).
Cr ysta llogr a p h ic An a lysis for [Ru 3Cl5(P P h 3)6]BP h 4‚
2.5CH2Cl2. Crystals suitable for X-ray diffraction study were
grown by layering of hexane on a CH2Cl2 solution of [Ru3Cl5-
(PPh3)6]BPh4. A brown prismatic single crystal with dimen-
sions of 0.22 × 0.14 × 0.10 mm was mounted on a glass fiber,
and diffraction data were collected on a Bruker SMART CCD
(32) Sheldrick, G. M. SADABS, Empirical Absorption Correction
Program; University of Go¨ttingen: Germany, 1996.
(33) SHELXTL Reference Manual (Version 5.1); Bruker Analytical
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