Unexpected effect of the ring on the extent of Si...H interligand interactions in half-sandwich silyl hydrides of ruthenium

Article abstract of DOI:10.1039/b806447d

This paper reports preparation of new silyl hydride complexes of ruthenium supported by the Cp/PR₃ ligand set. It is shown that the easiest and most general route to these complexes is provided by the thermal reaction of [RuCp(PR₃)(H

Full text of DOI:10.1039/b806447d

View Article Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/dalton | Dalton Transactions
Unexpected effect of the ring on the extent of Si ◊ ◊ ◊ H interligand interactions
in half-sandwich silyl hydrides of ruthenium†‡
Dmitry V. Gutsulyak,a,b Alexandr L. Osipov,b Lyudmila G. Kuzmina,c Judith A. K. Howardd and
Georgii I. Nikonov*a,b
Received 16th April 2008, Accepted 6th August 2008
First published as an Advance Article on the web 14th October 2008
DOI: 10.1039/b806447d
This paper reports preparation of new silyl hydride complexes of ruthenium supported by the Cp/PR3
ligand set. It is shown that the easiest and most general route to these complexes is provided by the
thermal reaction of [RuCp(PR3)(H)3] with hydrosilanes. Complexes [RuCp(PR3)(H)2(SiMe2Cl)] exhibit
Interligand Hypervalent Interactions (IHI) between the hydride and silyl ligands. Comparison of the
X-ray structures of complexes [RuCp(PPri3)(H)2(SiMe2Cl)], [RuCp(PPhPri2)(H)2(SiMe2Cl)], and
[RuCp(PPh3)(H)2(SiMe2Cl)] shows that the IHI weakens with the decreasing electron-releasing ability
of the phosphine. Comparison of the X-ray structure of [RuCp(PPh3)(H)2(SiMe2Cl)] with the structure
of the previously reported complex [RuCp*(PPh3)(H)2(SiMe2Cl)] reveals that the lack of IHI in the
latter compound is due to unfavourable steric interactions between the bulkier Cp* ring and the
SiMe2Cl group.
complexes [RuCp*(PR3)(H)2(SiR’3-nCln)] (n = 1–3) afforded struc-
tural features consistent with the presence of Si ◊ ◊ ◊ H hypervalent
interactions in these compounds.4b To elucidate the effect of
the cyclopentadienyl ligand on the extent of Si ◊ ◊ ◊ H bonding,
we sought to investigate complexes [RuCp(PR3)(H)2(SiMe2Cl)]
bearing an unsubstituted Cp-ring. Systematic X-ray studies reveal
an unexpected interplay of steric and electronic effects of the
cyclopentadienyl ring, influencing the occurrence of IHI in these
systems.
Introduction
The Cp*/PR3 ligand set is known to support a variety of
organosilicon ligands in the coordination sphere of ruthenium.1–5
Some of them, such as silylene1 and silene2 complexes, have un-
usual metal–ligand bonds, others exhibit nonclassical interligand
interactions.3,4,6–8 In contrast, the corresponding chemistry of the
RuCp(PR3) fragment is almost untapped.9,10 In this class, only
two examples of hydride silyl derivatives, the disilyl complexes
[RuCp(PR3)(H)(SiX3)2] (R= Me, X = Et; R = Ph, X = Cl)
prepared in mixtures with the monosilyls [RuCp(PR3)2(SiX3)],
have been reported so far.10 Such a situation has emerged primarily
due to the absence of readily available precursors to the chemistry
of the RuCp(PR3) moiety and hence due to the lack of convenient
synthetic strategies to its hydride and silyl derivatives.
As part of our on-going research on Interligand Hypervalent
Interactions (IHI),11–13 we became interested in exploring the
chemistry of silyl hydride derivatives of the fragment RuCp’(PR3)
(Cp’ = Cp or substituted Cp).4 We have argued previously4b
that the RuCp’(PR3) moiety is isolobal with the MCp2 (M =
Nb, Ta, Ti),11 MCp(RN) (M = V, Nb, Ta)12 and M(RN)2
(M = Mo, W)13 platforms that are known to support IHI
between a silyl and hydride ligands. Indeed, X-ray studies of
Results and discussion
Precursor complexes [RuCp(PPh3)(PPhMe2)X] (X = Cl, H)
Our initial strategy in targeting the synthesis of hydride silyl com-
plexes [RuCp(PR3)(H)2(SiMe2Cl)] consisted in the preparation of
precursor compounds [RuCp(PR3)(PR3’)(X)] (X = Cl, H) featur-
ing two phosphine ligands with very different basicities. We an-
ticipated that a good donating phosphine PR3 would stabilize the
formally Ru(IV) centre in the product [RuCp(PR3)(H)2(SiMe2Cl)]
whereas the poorly donating phosphine PR3’ would serve as a good
leaving group, thus avoiding the formation of monosilyl complexes
[RuCp(PR3)2SiX3] previously observed by Lemke et al.10
aChemistry Department, Brock University, 500 Glenridge Ave., St.
Catharines, L2S 3A1, ON, Canada. E-mail: gnikonov@brocku.ca;
Fax: (905) 9328846; Tel: (905) 6885550 Ext 3350
(1)
bChemistry Department, Moscow State University, Vorob’evy Gory, 119992,
Moscow, Russia
cInstitute of General and Inorganic Chemistry RAS, Leninskii Prosp. 31,
119991, Moscow, Russia
The mixed phosphine complexes [RuCp(PR3)(PPh3)(Cl)] (1,
PR3 = PPri2Me (a), PPhMe2 (b)) were prepared by heating the
readily available precursor [RuCp(PPh3)2(Cl)] (1c) with an equiva-
lent of phosphine PR3 in toluene for 4 h at 110 ◦C (eqn (1)). Under
these conditions, a selective substitution of only one PPh3 group
was observed.14 Analogous reaction with a bulkier phosphine PPri3
dChemistry Department, University of Durham, South Road, Durham, UK
DH1 3LE
† CCDC reference numbers 685290–685292. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/b806447d
‡ Dedicated to Professor Yu. I. Baukov on the occasion of his 70th birthday.
This journal is
The Royal Society of Chemistry 2008
Dalton Trans., 2008, 6843–6850 | 6843
©

View Article Online
did not occur. The complexes [RuCp(PR3)(PPh3)(H)] (2, PR3 =
PPri2Me (a), PPhMe2 (b)) were prepared by the reaction of 1 with
LiAlH4 in cold THF.
to-generate RuCp(PPhMe2) fragment. Indeed, the thermolysis of
[RuCp(PPhMe2)(PPh3)(Cl)] (1b) with HSiMeCl2 led exclusively
to the silyl product [RuCp(PPh3)(PPhMe2)(SiMeCl2)] (7b). The
possible dihydride product [RuCp(PPhMe2)(H)2(SiMeCl2)] (8b)
1
Reactions of [RuCp(PPh3)(PPhMe2)(X)] (X = Cl, H) with
was not formed in detectable amounts (by H NMR), but the
HSiMe2Cl
co-product MeSiCl3 was observed in an NMR tube reaction. As-
suming that the reaction proceeds via the usually invoked sequence
of phosphine dissociation, Si–H addition, Si–Cl elimination and
second Si–H addition (Scheme 2),1a we conclude that under these
conditions the elusive species 8b is amenable to dihydrogen elimi-
nation to give the unsaturated species [RuCp(PPhMe2)(SiMeCl2)]
(9b). Trapping this intermediate with PPh3 would afford 7b.
Consistent with this mechanism, complex 7b is also produced in
the reaction of [RuCp(PPhMe2)(PPh3)(H)] (2b) with HSiMeCl2.
So far such a dihydrogen elimination from trisubstituted cyclopen-
tadienyl complexes of ruthenium was observed only for complexes
[RuCp*(PR3)(X)(H)2] with X = halogen5c or X = H.5d
To our surprise, the mono(hydride) complexes 2a,b turned out to
be inactive towards addition of HSiMe2Cl even under prolonged
(12 h) heating in toluene (120 ◦C). However the reactions of
mono(chloride) precursors 1a and 1c with excess of HSiMe2Cl
◦
in toluene at 110 C do give mixtures containing the target silyl
dihydrides [RuCp(PR3)(H)2(SiMe2Cl)] (3a and 3c). The products
were characterized by spectroscopic methods and by X-ray
structure for 3c. When these reactions were carried out in NMR
tubes, the formation of an equivalent of co-product Cl2SiMe2 was
observed. In contrast, under identical conditions the complex
[RuCp(PPhMe2)(PPh3)(Cl)] (1b) bearing a smaller phosphine
PR3 = PPhMe2 afforded only the corresponding mono(hydride)
2b. These observations can be rationalized as shown in Scheme 1.
Dissociation of the poorer donor phosphine from 1 gives an
unsaturated intermediate [RuCp(PR3)(Cl)] (4a–c) which under-
goes Si–H addition reaction to give 5a–c. The subsequent Cl–
Si elimination reaction affords the monohydride intermediate 6
which can either undergo a second act of Si–H oxidative addition
or add phosphine to give 2. Since steric hindrance in the hydride
2 is reduced in comparison with the related chloride 1, increased
interphosphine repulsion in complexes 2 is required to generate
the intermediate 6. To test this hypothesis, we carried out the
reaction of 1b with an excess of HSiMe2Cl in the presence of
a phosphine sponge BMe3 assumed to shift the equilibrium in
Scheme 1 to the right. Under these conditions, the target silyl
complex [RuCp(PPhMe2)(H)2(SiMe2Cl)] (3b) was formed as the
main product.
Scheme 2 Preparation of complex [RuCp(PPhMe2)(PPh3)(SiMeCl2)]
(7b).
Interestingly, an NMR tube reaction of the related complex
[RuCp(PPri2Me)(PPh3)(H)] (2a) with excess of HSiMeCl2 affords
the bis(silyl) derivative [RuCp(PPri2Me)(SiMeCl2)2(H)] (10a). We
believe that this reaction takes a similar path to that discussed
for [RuCp(PPhMe2)(PPh3)(H)] (2b) with the exception that the
intermediate [RuCp(PPri2Me)(SiMeCl2)] (9a) is intercepted by
HSiMeCl2 rather than phosphine PPh3. This difference with the
analogous PPhMe2 chemistry possibly reflects the greater ability of
the RuCp(PPri2Me) fragment, ligated by a more donor phosphine,
to support a higher oxidation state of ruthenium. Attempted
scaling-up of this reaction gave a difficult-to-separate mixture of
silyl hydride products.
Reactions of [RuCp(PR3)(H)3] with HSiMe2Cl
Our search for a more general entry into the chemistry of the
RuCp(PR3) fragment has recently resulted in the syntheses of
precursor complexes [RuCp(PR3)(H)3] (11).15 Thermal reactions
of the latter with HSiMe2Cl afforded the desired silyl derivatives
[RuCp(PR3)(H)2(SiMe2Cl)] (3) in good yields (eqn (2)). The silyl
redistribution products [RuCp(PR3)(H)2(SiMeCl2)], formation of
which complicated the corresponding Cp* chemistry,4b were not
observed in any significant amount. This result is hard to ratio-
nalize because in the analogous reactions of [RuCp*(PR3)(H)3]
we noticed that decreasing steric bulk of phosphine favoured the
formation of “rearranged” products [RuCp*(R3P)(H)2(SiMeCl2)].
The effect of steric congestion around Ru in the present case is not
clear since complexes 3 feature bulky phosphine ligands but a
much less sterically demanding cyclopentadienyl ring.
Scheme 1 Reactions of mono(chlorides) [RuCp(PR3)(PPh3)(Cl)] (1a–c)
with HSiMe2Cl.
Reactions of [RuCp(PPh3)(PPhMe2)(X)] (X = Cl, H) with
HSiMeCl2
Given the ability of electron-withdrawing groups at silicon to stabi-
lize M–Si bonds, we believed that more Lewis acidic silanes would
promote the formation of silyl derivatives even for the difficult-
6844 | Dalton Trans., 2008, 6843–6850
This journal is
The Royal Society of Chemistry 2008
©

View Article Online
◦
a
a
˚
Table 1 Bond lengths (A) and angles ( ) for 3e, 3f and 12f
3e 3f
12f
(2)
Ru(1)–Si(1)
Si(1)–Cl(1)
Ru(1)–P(1)
Ru(1)–H(1)
2.3286(8)
2.164(1)
2.2933(8)
1.56(4)
2.3377(7)
2.153(2)b
2.3056(6)
1.51(3)
2.332(1)
2.026(7)b
2.3095(9)
1.51(4)
Complexes 3c–f were characterized by NMR and IR spec-
troscopy and by X-ray studies of 3c, 3e, and 3f. In particular,
the hydrides give rise to doublets at about -12 ppm coupled to one
phosphorus nucleus. The IR spectra exhibit bands in the typical
region for Ru–H bonds.
Ru(1)–H(2)
Si(1)–H(1)
Si(1)–H(2)
Si(1)–C(6)
1.48(4)
2.11(4)
2.20(4)
1.868(4)
1.874(3)
105.62(3)
112(2)
100.0(2)
100.8(1)
105.5(2)
153(1)
1.50(3)
2.02(3)
2.09(4)
1.89(1)
1.881(3)
107.62 (2)
106(2)
101.1(4)
101.4(1)
102.7 (4)
152.9(9)
1.53(4)
2.03(4)
2.04(4)
1.898(3)c
1.94(1)
Si(1)–C(7)
P(1)–Ru(1)–Si(1)
H(2)–Ru(1)–H(1)
C(6)–Si(1)–Cl(1)
C(7)–Si(1)–Cl(1)
C(6)–Si(1)–C(7)
H(1)–Si(1)–Cl(1)
102.69(3)
109(2)
101.2(2)
101.9(4)
100.8(4)
153(2)
Molecular structures of 3c, 3e, and 3f
The X-ray structures of complexes 3e and 3f are shown in
Fig. 1 and 2, respectively, and selected molecular parame-
ters are gathered in Table 1, where data for related complex
[RuCp*(PPri3)(H)2(SiMe2Cl)] (12f) are given for comparison. The
appearance of both structures is very similar and resembles
a The SiMe2Cl is rotationally disordered, the data are reported only for the
major conformer (84% in case of 3f). Complex 12f was reported in ref. 4b.
b This Si–Cl bond length is inaccurate because of rotational disorder of
SiMe2Cl. c In ref. 4b, the atom C(6) in structure 12f was labeled as C(11)
and atom C(7) was C(12).
those of the previously reported Cp* analogues 12f and
[RuCp*(PMePri2)(H)2(SiMe2Cl)] (12a). The silyl group is oriented
in such a way that the chloride substituent is approximately trans
to one of the hydrides, a feature typical for all complexes with
IHI.11–13,16 Unfortunately, direct comparison of the key molecular
parameters of the silyl groups in 3e and 3f is not possible because
of rotational disorder of the SiMe2Cl group in 3f. An analogous
problem has been observed for its Cp* congener 12f. Like 12a and
other complexes with IHI,11–13,16 the Si–Cl bond (2.164(1) A) in 3e is
˚
elongated.17 However, this value is slightly smaller than that in 12a
˚
(2.170(1) A), possibly due to the diminished donating ability of the
aryl substituted phosphine PhPri2P present in 3e.18 The Ru–Si and
Ru–P bonds in 3e and 3f are comparable with the corresponding
bonds in the Cp* analogues. The major difference between the
Cp and Cp* series is the increased (by 5◦) P–Ru–Si bond angles
in the unsubstituted complexes. Obviously, this difference reflects
the decreased steric demand of the ring in the Cp series.
As expected, the compound 3c bearing a much less donating
phosphine PPh3 differs from complexes 3e and 3f in that it exhibits
a significantly reduced IHI (Fig. 3 and Table 2). This is seen both
Fig. 1 Molecular structure of 3e with thermal ellipsoids at 50% proba-
bility level. Hydrogen atoms, excluding hydride ligands, are omitted for
clarity.
˚
˚
from the shorter Si–Cl bond (2.152(2) A versus 2.164(1) A in 3e)
˚
and longer Ru–Si bond length (2.354(1) A versus 2.3286(8) in
3e and 2.3377(7) in 3f).17 Note that the latter trend contradicts
the common expectation that in a complex with a less donating
trans-phosphine (PPh3) the Ru–Si bond should be shorter due to
increased trans influence of the silyl. Obviously, the shortening of
the Ru–Si bond due to IHI in 3e and 3f overweighs the difference
in trans influence of phosphines.18
However, the most surprising result is obtained upon the
comparison of 3c with the related compound [RuCp*(PPh3)(H)2-
(SiMe2Cl)]4c (12c) (Table 2). Initially we anticipated that complexes
having a more electron releasing Cp* ring, but bearing the same
phosphine, would have increased IHI because of increased basicity
of the hydride. The compound 12c has been previously shown
to have no or only very weak IHI, which was then ascribed to
the reduced electron-releasing ability of the PPh3 ligand.4c The
comparison of molecular structures of 3c and 12c now shows
Fig. 2 Molecular structure of 3f with thermal ellipsoids at 50% probabil-
ity level. The SiMe2Cl ligand is disordered over two positions occupied by
the Cl(1) and C(6)H3 groups. Hydrogen atoms, excluding hydride ligands,
are omitted for clarity.
This journal is
The Royal Society of Chemistry 2008
Dalton Trans., 2008, 6843–6850 | 6845
©

View Article Online
Fig. 3 Comparison of molecular structures of 3c (left) and 12c (right) with thermal ellipsoids at 50% probability level. Hydrogen atoms, except the
hydride ligands, are omitted for clarity.
Table 2 Comparison of molecular parameters in for 3c and 12c4b (bond
PPri3. Unfortunately, both these structures suffer from a disorder
of the SiMe2Cl group, making the comparison of the Si–Cl
bond lengths unreliable. Nevertheless, both the 3f and 12f exhibit
◦
˚
lengths (A) and angles ( ))
3c
2.3544(4)
2.1518(5)
2.2762(3)
1.51(2)
1.54(2)
2.11(5)
2.04(7)
1.864(1)
1.905(1)
105.76(1)
104(1)
100.17(5)
100.76(5)
107.60(7)
145(1)
12c
2.364(2)
˚
almost identical Ru–Si bond lengths (2.3377(6) and 2.332(1) A,
respectively), which suggests that in the case of more donating
phosphines, the steric and electronic effects of the Cp* substituent
are counterbalanced.
Ru(1)–Si(1)
Si(1)–Cl(1)
Ru(1)–P(1)
Ru(1)–H(1)
Ru(1)–H(2)
Si(1)–H(1)
Si(1)–H(2)
Si(1)–C(6)
2.143(3)
2.265(2)
1.49(2)
1.50(2)
2.26(5)
2.19(3)
1.901(9)
1.872(8)
103.52(8)
109(2)
97.9(3)
99.7(3)
106.0(4)
137(1)
Conclusions
Si(1)–C(7)
We have shown that reactions of the trihydrides [RuCp(PR3)(H)3]
with hydrosilanes provide a clean and general access to the hy-
drido silyl complexes [RuCp(PR3)(H)2(SiMe2Cl)]. Like their Cp*
analogues, these compounds exhibit IHI between the hydride and
silyl ligands, whose strength decreases with the decreasing basicity
of the supporting phosphine (from PPri3 to PPh3). Comparison of
the X-ray structure of the complex [RuCp(PPh3)(H)2(SiMe2Cl)]
(3c) with the structure of the previously reported analogue
[RuCp*(PPh3)(H)2(SiMe2Cl)] (12c), shows that the lack of IHI
in the latter compound is due to unfavourable steric interactions
between the bulkier Cp* ring and the SiMe2Cl group, rather than
due to the insufficient electron-releasing ability of the PPh3. For
more basic phosphines, it appears that electronic effect of the Cp*
ring (a more electron releasing ligand making the hydride more
basic) is almost compensated by the increased steric size of the
ring, which in turn hampers the interactions between the silyl and
hydride ligands.
P(1)–Ru(1)–Si(1)
H(2)–Ru(1)–H(1)
C(6)–Si(1)–Cl(1)
C(7)–Si(1)–Cl(1)
C(7)–Si(1)–C(6)
H(1)–Si(1)–Cl(1)
H1–Ru1–Si1–Cl1
163(1)
141(1)
that this expectation does not hold, at least for the case of PPh3.
A closer inspection of the molecular structures of 3c and 12c,
however, allows us to explain this apparently puzzling situation:
One of the pre-requisites of IHI is that the Cl substituent at silicon
should be placed opposite to a hydride ligand to allow for overlap
between the s(M–H) bonding orbital and s*(Si–Cl) antibonding
orbitals.11–13 In 3c, as in 3e and 3f, this stereochemical condition
leads to such a conformation of the silyl ligand that one of the Me
groups comes close to the ring. In 12c, such an optimum geometry
is not possible because the relatively weak Si–H interaction cannot
compensate the increased steric interactions between the Cp* and
silicon-bound Me group. This results in the rotation of the SiMe2Cl
ligand and effective “switching off” of the IHI in 12c.
Experimental
It would be interesting to verify this rationalization by com-
paring the structures of Cp and Cp* analogues, having a donating
phosphine ligand and presumably stronger IHI. The only donating
phosphine, for which X-ray structures are available so far for
both the Cp and Cp* derivatives (3f and 12f, respectively), is
All manipulations were carried out, using conventional high-
vacuum or argon-line Schlenk techniques. Solvents were dried
over sodium or sodium benzophenone ketyl and either kept under
argon or distilled into the reaction vessel by high vacuum gas phase
transfer. NMR spectra were recorded on a Bruker (1H, 300 MHz;
6846 | Dalton Trans., 2008, 6843–6850
This journal is
The Royal Society of Chemistry 2008
©

View Article Online
13C, 75.4 MHz) and Varian (1H, 400 MHz; 13C, 100.6 MHz;
31P, 161.9 MHz) spectrometers. IR spectra were obtained as
Nujol mulls with an ATI Mattson FTIR spectrometer spectrom-
eter. RuCl3*aq was obtained from Precious-Metals-on-Line, and
silanes were purchased from Sigma-Aldrich. PPhCl2 was a gift
from CYTEC. Complexes Cp(PR3)RuH315, Cp(PPh3)2RuCl,19 and
phosphines were prepared according to the literature methods.
Reaction of [RuCp(PPh3)2(Cl)] (1c) with HSiMe2Cl in the presence
of PPri3
HSiMe2Cl (0.23 mL, 2.1 mmol) and PPri3 (0.070 mL, 0.36 mmol)
were added to
a solution of [RuCp(PPh3)2(Cl)] (0.11 g,
0.15 mmol) in 20 mL of toluene. The reaction mixture was
refluxed for 9 h. All the volatiles were removed under vacuum.
NMR spectra showed the formation of a mixture of prod-
ucts [RuCp(PPh3)(H)2(SiMe2Cl)] (3c) (40%) and [RuCp(PPri3)-
(H)2(SiMe2Cl)] (3f) (60%).
Synthesis of [RuCp(PPh3)(PPri2Me)(Cl)] (1a)
PPri2Me (0.090 g, 0.69 mmol) was added to a solution of
[RuCp(PPh3)2Cl] (0.50 g, 0.69 mmol) in toluene (50 mL). The
reaction mixture was refluxed for 4 h. Then all volatiles were
removed under vacuum. The resultant dark brown oil was
dissolved in 10 mL of toluene and passed through a plug of silica
gel (100 ¥ 15 mm), collecting the yellow band eluted with ether.
The solvent was removed under vacuum, affording 1a as a yellow
crystalline solid. Yield 0.33 g (80%). NMR data are in agreement
with published data.14
Reaction of [RuCp(PPh3)(PPhMe2)(Cl)] (1b) with HSiMe2Cl
To a solution of [RuCp(PPh3)(PPhMe2)(Cl)] (0.36 g, 0.60 mmol)
in toluene (30 mL) was added HSiMe2Cl (1.00 mL, 8.98 mmol).
The reaction mixture was refluxed for 12 h. Then all volatiles were
removed under vacuum and the resulting dark orange oil was
washed with ether until a yellow crystalline solid formed. NMR
spectra showed the formation of [RuCp(PPh3)(PPhMe2)(H)] (2b).
Yield 0.24 g (70%).
Reaction of Cp(Ph3P)(PPhMe2)RuCl (1b) with HSiMe2Cl in
presence of BMe3
Synthesis of [RuCp(PPh3)(PPhMe2)(Cl)] (1b)
This complex was prepared analogously to 1a. Yield 82%. NMR
To a solution of [RuCp(PPh3)(PPhMe2)(Cl)] (0.55 g, 0. 91 mmol)
in toluene (20 mL) was added HSiMe2Cl (1.89 g, 20 mmol) and
a solution of BMe3 (~9 mmol) in toluene (20 mL). The resulting
mixture was refluxed for 9 h. Then all volatiles were removed
under vacuum. The resulting residue was extracted with hexane
(3 ¥ 20 mL) in order to separate the product from the insoluble
in hexane PPh3·BMe3. The solvent was removed under vacuum.
NMR spectra showed the formation of a mixture of compounds,
with [RuCp(PPhMe2)(H)2(SiMe2Cl)] being the main component
(60%). [RuCp(PPhMe2)(H)2(SiMe2Cl)] (3b), selected NMR data:
1H NMR (C6D6): d 4.73 (s, 5H, C5H5), 0.70 (s, 6H, SiCH3), -11.36
(d, J(P-H) = 8.4 Hz, 2, RuH2). 31P NMR (C6D6): d 70.4.
data are in agreement with published data.20
Synthesis of [RuCp(PPh3)2(H)] (2c)
To a mixture of [RuCp(PPh3)2(Cl)] (4.0 g, 5.5 mmol) and LiAlH4
(2.0 g, 52 mmol) was added 30 mL of THF at -30 ◦C. The
reaction mixture was slowly warmed to ambient temperature and
was further stirred for 20 h. Degassed water was slowly added to
the solution until the evolution of gas ceased. The solution was
dried in vacuo and the residue was extracted with toluene (3 ¥
30 mL). The solvent was evaporated and the resulting orange oil
was washed with cold ether (3 ¥ 10 mL) until crystalline solid was
obtained. Yield 3.2 g (84%). NMR data are in agreement with
published data.21
Synthesis of [RuCp(PPh3)(H)2(SiMe2Cl)] (3c)
Method a. This complex was prepared analogously to 3f. Yield
67%.
Synthesis of [RuCp(PPh3)(PPri2Me)(H)] (2a)
Method b. To a solution of [RuCp(PPh3)2(Cl)] (1.6 g,
2.2 mmol) in toluene was added HSiMe2Cl (5.1 g, 54 mmol).
The reaction mixture was refluxed for 5 h. Then all volatiles were
removed under vacuum. The resulting orange oil was extracted
with ether (50 mL). A yellow crystalline product was obtained by
slow crystallization from ether solution at ambient temperature.
Yield 0.35 g (30%). 1H NMR (C6D6): d 6.49–7.55 (m, 15, PPh3),
4.73 (s, 5, C5H5), 0.63 (s, 6, Si(CH3)2), -11.34 (d + sat, J(P-H) =
26.3 Hz, J(Si-H) = 14.3 Hz, 2, RuH2). 13C NMR (C6D6): d 139.3
(d, J(P-C) = 47.9 Hz, PPh3), 133.9 (d, J(P-C) = 11.2 Hz, PPh3),
84.7 (s, C5H5), 17.6 (s, Si(CH3)2). 31P NMR (C6D6): d 70.6. IR
(Nujol): n(Ru-H) = 1993 cm-1. Anal. Calcd. for C25H28ClPRuSi:
C, 57.30; H, 5.39. Found: C, 57.27, H, 5.36.
This complex was prepared analogously to 2c. Yield 80%. NMR
data for complex 2a are in agreement with published data.14
Synthesis of [RuCp(PPh3)(PPhMe2)(H)] (2b)
1
This complex was prepared analogously to 2c. Yield 80%. H
NMR (C6D6): d 7.75 (m, 6H, PPh3), 7.38 (m, 2H, PPhMe2), 7.0–
7.1(m, 12H, PPh3 and PPhMe2), 4.54 (s, 5, C5H5), 1.18 (d, J(P-
H) = 8.2 Hz, 3, PCH3), 1.16 (d, J(P-H) = 8.2 Hz, 3, PCH3),
-11.90 (t, J(P-H) = 34.4 Hz, 1, RuH). 31P NMR (C6D6): d 73.3
(d, J(P-P) = 37 Hz, PPh3), 24.9 (d, J(P-P) = 37 Hz, PPhMe2). 13
C
1
NMR (C6D6): d 142.2 (d, J(P-C) = 38 Hz, Ph), 134.1 (d, J(P-
C) = 11 Hz, 2,6Ph), 128.1 (s, 4Ph), 127–128 (m,3,5Ph), 80.4 (s, C5H5),
24.6 (d, J(P-C) = 28 Hz, PPhMeaMeb), 23.2 (d, J(P-C) = 26 Hz,
PPhMeaMeb). IR(Nujol): n(Ru-H) = 1943 cm-1. Anal. Calcd. for
C31H32P2Ru: C, 65.60, H, 5.68. Found: C, 65.91, H, 6.03.
Synthesis of [RuCp(PPriPh2)(H)2(SiMe2Cl)] (3d)
This complex was prepared analogously to 3f and isolated as an
1
ether solvate. Yield 69%. H NMR (C6D6): d 7.44 (m, 4, 3,5Ph),
This journal is
The Royal Society of Chemistry 2008
Dalton Trans., 2008, 6843–6850 | 6847
©

View Article Online
7.01 (m, 6, 2,4,6Ph), 4.66 (s, 5, C5H5), 2.32 (d sept, J(P-H) = 7.5 Hz,
J(H-H) = 6,6 Hz, 1, P(CH(CH3)2)3), 0.87 (s, 6, SiMe2), 0.83 (dd,
J(P-H) = 16.1 Hz, J(H-H) = 6.6 Hz, 6, P(CH(CH3)2)3), -11.71
(d + sat, J(P-H) = 26.0 Hz, J(Si-H) = 12.5 Hz, 2, H). 13C NMR
(C6D6): d 138.7 (d, J(P-C) = 41.7 Hz, Ph), 132.7 (d, J(P-C) =
9.9 Hz, Ph), 129.1 (d, J(P-C) = 2.2 Hz, Ph), 85.1 (s, C5H5), 28.9
(d, J(P-C) = 30.7 Hz, P(CH(CH3)2)2), 18.6 (s, P(CH(CH3)2)2), 18.1
(s, Si(CH3)2). 31P NMR (C6D6): d 77.8 (s). IR (Nujol): n(Ru-H) =
1989 cm-1. Anal. Calcd. for C21H37O0.5ClPRuSi (3d.0.5Et2O): C,
54.69; H, 6.69. Found: C, 55.23; H, 6.23.
NMR (C6D6): d 6.85–7.73 (m, 20, Ph), 4.52 (s, 5, C5H5), 1.67
(d, J(P-H) = 8.4 Hz, 3, PCH3), 1.37 (d, J(P-H) = 8.4 Hz,
3, PCH3), 1.07 (s, 3, SiCH3). 13C NMR (C6D6): d 145.3 (d,
J(P-C) = 45.9 Hz, P(1Ph)Me2), 139.5 (d, J(P-C) = 41.1 Hz,
P(1Ph)3), 134.1 (d, J(P-C) = 10.6 Hz, P(2,6Ph)3), 129.6 (d, J(P-
C) = 8.6 Hz, P(2,6Ph)Me2), 129.4 (s, P(3,5Ph)3), 86.1 (s, C5H5),
24.3 (d, J(P-C) = 30.8 Hz, PCH3), 21.5 (s, Si(CH3)2), 19.5 (d,
J(P-C) = 28.9 Hz, PCH3). 31P NMR (C6D6): d 56.7 (d, J(P-
P) = 35 Hz, PPh3), 14.7 (d, J(P-P) = 35 Hz, PPhMe2). Anal.
Calcd. for C32H34Cl2P2RuSi: C, 56.47; H, 5.04. Found: C, 56.44;
H, 5.02.
Synthesis of [RuCp(PPri2Ph)(H)2(SiMe2Cl)] (3e)
This complex was prepared analogously to 3f. Yield 60%. 1H NMR
(C6D6): d 7.40–7.04 (m, 5, Ph), 4.70 (s, 5, C5H5), 1.87 (d sept,
J(P-H) = 7.3 Hz, J(H-H) = 6.6 Hz, 2, P(CH(CH3)2)3), 0.89 (dd,
J(P-H) = 15.9 Hz, J(H-H) = 6.6 Hz, 6, P(CH(CH3)2)), 0.88 (s,
2, Si(CH3)2)), 0.64 (dd, J(P-H) = 14.3 Hz, J(H-H) = 7.0 Hz,
6, P(CH(CH3)2), -11.97 (d + sat, J(P-H) = 26.0 Hz, J(Si-H) =
13.0 Hz, 2, RuH). 13C NMR (C6D6): d 133.4 (d, J(P-C) = 8.8 Hz,
2,6Ph), 133.1 (d, J(P-C) = 31.8 Hz, 1Ph), 129.3 (d, J(P-C) = 2.2 Hz,
4Ph), 127.1 (d, J(P-C) = 7.7 Hz, 3,5Ph), 84.6 (s, C5H5), 25.1 (d,
J(P-C) = 29.6 Hz, P(CH(CH3)2)2), 18.1 (s, Si(CH3)2), 17.8 (d, J(P-
C) = 3.3Hz, P(CH(CaH3)2)2), 17.1 (s, P(CH(CbH3)2)2). 31P NMR
(C6D6): 85.4 (s). IR (Nujol): n(Ru-H) = 2009 cm-1. Anal. Calcd.
for C19H32ClPRuSi: C, 50.04; H, 7.07. Found: C, 50.08; H, 7.35.
Generation of [RuCp(PPri2Me)(SiMeCl2)2(H)] (8a)
To a solution of [RuCp(PPri2Me)(PPh3)(H)] (0.024 g, 0.040 mmol)
in C6D6 in an NMR tune was added HSiMeCl2 (0.049 g,
0.40 mmol). The reaction mixture was heated for 48 h at
120 ◦C. Then all the volatiles were removed under vacuum and the
resulting yellow oil was dissolved in C6D6. Yield 70% (according
1
1
to the integration of the H NMR spectrum). H NMR (C6D6):
d 4.82 (s, 5, C5H5), 1.95 (d sept, J(P-H) = 7.3 Hz, J(H-H) =
6.9 Hz, 2, P(CH(CH3)2)2), 1.45 (s, 6, SiMe), 1.26 (d, J(P-H) =
9.5 Hz, 3, PMe), 0.75 (dd, J(P-H) = 15.4 Hz, J(H-H) = 6.8 Hz, 6,
P(CH(CHa )2)2), 0.70 (dd, J(P-H) = 14.7 Hz, J(H-H) = 7.3 Hz,
3
6, P(CH(CHb )2)2), -10.7 (d + sat, J(P-H) = 27.2 Hz, J(Si-
3
H) = 19.7 Hz, 1, RuH). 13C NMR (C6D6): d 88.8 (s, C5H5),
30.9 (d, J(P-C) = 28.5 Hz, P(CH(CH3)2)2), 22.0 (s, SiMe), 18.9
(s, P(CH(CHa )2)2), 18.8 (s, P(CH(CHb )2)2), 14.1 (d, J(P-C) =
Synthesis of [RuCp(PPri3)(H)2(SiMe2Cl)] (3f)
3
3
32.9 Hz, PMe). 31P NMR (C6D6): d 46.7 (s). IR (Nujol): n(Ru-
To a solution of [RuCp(PPri3)(H)3] (0.20 g, 0.61 mmol) in toluene
(50 mL) was added HSiMe2Cl (0.67 mL, 6.1 mmol). The reaction
mixture was refluxed for 24 h. Then all volatiles were removed
under vacuum. The resulting dark brown oil was dissolved in ether
(20 mL) and the solution was filtered. The filtrate was concentrated
slowly during 5 days at ambient temperature to afford 3f as a
yellow crystalline solid. Yield 0.17 g (65%). 1H NMR (toluene-d8):
d 4.74 (d, J(P-H) = 0.5 Hz, 5, C5H5), 1.61 (d sept, J(H-H) =
7.0 Hz, J(P-H) = 9.2 Hz, 3, P(CH(CH3)2)3), 0.90 (dd, J(H-H) =
7.1 Hz, J(P-H) = 9.2 Hz, 9, PCH(CH)3), 0.85 (s, 6, Si(CH3)2),
H) = 2017 cm-1.
Crystal structure determinations
Crystals of 3c, 3e, and 3f were coated with polyperfluoro oil
and mounted on the Bruker Smart three-circle diffractometer
with CCD area detector at 123 K. The crystallographic data and
the characteristics of structure solution and refinement are given
in Table 3. The structure factor amplitudes for all independent
reflections were obtained after the Lorentz and polarization
corrections. The Bruker SAINT program22 was used for data
reduction. An absorption correction based on measurements of
equivalent reflections was applied (SADABS). The structures were
solved by direct methods23 and refined by full-matrix least squares
-12.46 (d + sat, J(P-H) = 25.1 Hz, J(Si-H) = 12.2 Hz, RuH2). 13
C
NMR (toluene-d8): d 84.1 (s, C5H5), 28.6 (d, J(P-C) = 23.6 Hz,
PCH(CH3)2], 19.4 (s, PCH(CH3)2), 18.3 (s, Si(CH3)2). 31P NMR
(toluene-d8): d 91.4. IR (Nujol): n(Ru-H) = 2012 cm-1. Anal.
Calcd. for C16H34ClPRuSi: C, 45.54; H, 8.12. Found: C, 45.61;
H, 8.07.
procedures, using w(|Fo2| - |Fc |)2 as the refined function.
2
The structure of 3f displays a disorder of the Cl atom and one
of two Me groups, C(6)H3, at the silicon atom, with the rate of site
occupation factors equal to 0.84:0.16. Although a contribution of
the minor component of the disorder is rather low, taking into
account this disorder results in a reduction of the final accuracy
Synthesis of [RuCp(PPh3)(PPhMe2)(SiMeCl2)] (7b)
(a) Solution of complex [RuCp(PPh3)(PPhMe2)(H)] (2b) and silane
HSiMeCl2 (~ 10 equivs) in 0.6 mL of C6D6 was heated in an NMR
tube at 100 ◦C. The reaction was monitored by NMR spectroscopy.
The formation 7b and MeSiCl3 was observed.
(b) To a solution of [RuCp(PPh3)(PPhMe2)(Cl)] (0.51 g,
0.83 mmol) in toluene (20 mL) was added HSiMeCl2 (1.38 g,
12 mmol). The reaction mixture was refluxed for 12 h. Then
all volatiles were removed under vacuum. The resulting yellow
oil was dissolved in ether (10 mL). A yellow crystalline product
was formed in a few days at -30 ◦C. Yield 0.5 g (88%). 1H
of the structure determination and lowering of the residual
-3
˚
electron density peak from 2.33 e A to a more acceptable value
-3
˚
0.555 e A .
In all structures the hydride atoms were found from the
difference electron density map and refined isotropically, whereas
all other hydrogen atoms were refined using the “riding” model.
For each structure, all non-hydrogen atoms were refined with
anisotropic thermal parameters.
6848 | Dalton Trans., 2008, 6843–6850
This journal is
The Royal Society of Chemistry 2008
©

View Article Online
Table 3 Crystal and structure refinement data for 3c, 3e and 3f
3c
3e
3f
Empirical formula
Formula weight
Colour, habit
C25H28ClPRuSi
524.05
Yellow, block
0.46 ¥ 0.42 ¥ 0.38
Triclinic
¯
P1
C19H32ClPRuSi
456.03
Yellow, block
0.36 ¥ 0.22 ¥ 0.08
Monoclinic
P21/c
C16H34ClPRuSi
422.01
Yellow, plate
0.18 ¥ 0.12 ¥ 0.04
Monoclinic
P21/n
Crystal size, mm3
Crystal system
Space group
Unit cell dimensions:
˚
a/A
8.7357(2)
11.5961(2)
11.9794(2)
73.757(1)
86.005(1)
82.276(1)
1153.85(4)
2
1.508
0.926
536
Bruker SMART
123(2)
(0.71073) Mo Ka
w
0.3
8.7462(1)
16.4554(3)
29.3627(5)
90
92.351(1)
90
4222.39(12)
8
1.435
1.000
1888
Bruker SMART
123(2)
(0.71073) Mo Ka
w
0.3
9.4433(2)
15.4953(4)
13.8057(4)
90
94.1670(10)
90
2014.80(9)
4
1.391
1.041
880
Bruker SMART
123(2)
(0.71073) Mo Ka
w
0.3
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
V/A
Z
3
˚
Density (calculated)/g cm-3
Absorption coefficient/mm-1
F(000)
Diffractometer
T/K
Radiation (lambda, A)
˚
Scan mode
Scan step (in omega)/◦
Time per step/s
15
15
15
Theta range for data collection/◦
Index ranges
1.77 to 29.00
-11 ≤ h ≤ 11, -15 ≤ k ≤ 15,
-16≤ l ≤ 16
1.39 to 28.5
1.48 to 28.00
-11 ≤ h ≤12, -20 ≤ k ≤ 20,
-15 ≤ l ≤ 18
14596
-11 ≤ h ≤11, -20 ≤ k ≤ 22,
-37 ≤ l ≤ 39
37465
Reflections collected
Independent reflections
Absorption correction
Max. transmission
Min. transmission
11526
6037 [R(int) = 0.0131]
10680 [R(int) = 0.0490]
4851 [R(int) = 0.0343]
Multi-scan
Multi-scan
Multi-scan
0.6753
0.7198
0.7148
0.9243
0.8348
0.9595
Refinement method
Full-matrix least-squares on
F2 (SHELXTL-Plus)
5783/0/271
Full-matrix least-squares on
F2 (SHELXTL-Plus)
7708/0/431
Full-matrix least-squares on F2
(SHELXTL-Plus)
3970/0/324
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I>2s(I)]
R indices (all data)
Largest diff. peak and hole/e A
Extinction coefficient
1.063
1.022
1.043
R1 = 0.0194, wR2 = 0.0525
R1 = 0.0203, wR2 = 0.0529
0.422 and -0.463
0.0046(5)
R1 = 0.0383, wR2 = 0.0795
R1 = 0.0653, wR2 = 0.0857
0.759 and -1.080
R1 = 0.0294, wR2 = 0.0545
R1 = 0.0441, wR2 = 0.0571
0.555 and -0.391
-3
˚
3 (a) J. Yin, J. Klosin, K. A. Abboud and W. M. Jones, J. Am. Chem. Soc.,
1995, 117, 3298; (b) S. T. N. Freeman, F. R. Lemke and L. Brammer,
Organometallics, 2002, 21, 2030; (c) F. R. Lemke, J. Am. Chem. Soc.,
1994, 116, 11183.
4 (a) A. L. Osipov, S. F Vyboishchikov, K. Y. Dorogov, L. G. Kuzmina,
J. A. K. Howard, D. A. Lemenovskii and G. I. Nikonov, Chem.
CommUN., 2005, 3349–3351; (b) A. L. Osipov, S. M. Gerdov, L. G.
Kuzmina, J. A. K. Howard and G. I. Nikonov, Organometallics, 2005,
24, 587–602; (c) S. B. Duckett, L. G. Kuzmina and G. I. Nikonov, Inorg.
Chem. Commun., 2000, 3/3, 126.
Acknowledgements
GIN thanks NSERC and Brock University for financial support.
LGK and JAKH thank the Royal Society (London) for a Joint
Research Grant and LGK thanks the Royal Society of Chemistry
(London) for a RSC Journal Grant for International Authors. We
are grateful to CYTEC for the gift of PhPCl2.
5 (a) B. K. Campion, R. H. Heyn and T. D. Tilley, Chem. Commun.,
1988, 278; (b) B. K. Campion, R. H. Heyn and T. D. Tilley, Chem.
Commun., 1992, 1201; (c) T. J. Johnson, P. S. Coan and K. G. Caulton,
Inorg. Chem., 1993, 32, 4594; (d) V. Rodriguez, B. Donnadieu, S. Sabo-
Etienne and B. Chaudret, Organometallics, 1998, 17, 3809; (e) S. T. N.
Freeman, L. L. Lofton and F. R. Lemke, Organometallics, 2002, 21,
4776; (f) F. R. Lemke, K. J. Galat and W. J. Youngs, Organometallics,
1999, 18, 1419.
6 For recent discussions of nonclassical Si ◊ ◊ ◊ H interligand interactions
see: (a) G. I. Nikonov, Adv. in Organomet. Chem., 2005, 53, 217–
309; (b) Z. Lin, Chem. Soc. Rev., 2002, 31, 239; (c) J. Y. Corey and
J. Braddock-Wilking, Chem. Rev, 1999, 99, 175.
References
1 Silylenes: (a) D. A. Straus, C. Zhang, G. E. Quimbita, S. K. Grumbine,
R. H. Heyn, T. D. Tilley, A. L. Rheingold and S. J. Geib, J. Am. Chem.
Soc., 1990, 112, 2673; (b) D. A. Straus, T. D. Tilley, A. L. Rheingold
and S. J. Geib, J. Am. Chem. Soc., 1987, 109, 5872; (c) S. K. Grumbine,
T. D. Tilley, F. P. Arnold and A. L. Rheingold, J. Am. Chem. Soc., 1994,
116, 5495; (d) D. A. Straus, S. K. Grumbine and T. D. Tilley, J. Am.
Chem. Soc., 1990, 112, 7801; (e) S. K. Grumbine, G. P. Mitchell, D. A.
Straus, T. D. Tilley, A. L. Rheingold and S. J. Geib, Organometallics,
1998, 17, 5607; (f) P. B. Glaser and T. D. Tilley, J. Am. Chem. Soc.,
2003, 125, 13640; (g) B. K. Campion, R. H. Heyn and T. D. Tilley,
Organometallics, 1992, 11, 3918.
7 (a) For more general discussion of nonclassical interligand bonding
see: G. J. Kubas, Metal Dihydrogen and s-Bond Complexes, Kluwer
Academic/Plenum, New York, 2001; (b) R. H. Crabtree, Angew. Chem.,
Int. Ed. Engl., 1993, 32, 789.
2 Silenes: (a) B. K. Campion, R. H. Heyn and T. D. Tilley, J. Am. Chem.
Soc., 1988, 115, 7558; (b) B. K. Campion, R. H. Heyn, T. D. Tilley and
A. L. Rheingold, J. Am. Chem. Soc., 1993, 115, 5527.
This journal is
The Royal Society of Chemistry 2008
Dalton Trans., 2008, 6843–6850 | 6849
©

View Article Online
8 Nonclassical Si–H interactions in non-Cp complexes of Ru: (a) S.
Lachaize and S. Sabo-Etienne, Eur. J. Inorg. Chem., 2006, 2115;
(b) S. Lachaize, A. Caballero, L. Vendier and S. Sabo-Etienne,
Organometallics, 2007, 26, 3713; (c) Nonclassical Si–H interaction
in a silacyclopentadienyl complex of Ru:W. P. Freeman, T. D.
Tilley and A. L. Rheingold, J. Am. Chem. Soc., 1994, 116,
8428.
9 (a) S. T. N. Freeman, L. L. Lofton and F. R. Lemke, Organometallics,
2002, 21, 4776; (b) F. R. Lemke, K. J. Galat and W. J. Youngs,
Organometallics, 1999, 18, 1419.
Cowley, N. H. Rees, A. G. Razuvaev, P. Mountford and G. I. Nikonov,
Chem.-Eur. J., 2008, 14, 296–310.
13 S. K. Ignatov, S. R. Dubberley, N. H. Rees, A. G. Razuvaev, P.
Mountford and G. I. Nikonov, manuscript in preparation.
14 Some related mixed diphosphine complexes Cp(R3P)(R¢3P)RuCl have
been previously reported: (a) A. Coto, M. J. Tenorio, M. C. Puerta
and P. Valerga, Organometallics, 1998, 17, 4392–4399; (b) F. L. Joslin,
J. T. Mague and D. M. Roundhill, Organometallics, 1991, 10, 521–524;
(c) T. Blackmore, M. I. Bruce and F. G. A. Stone, J. Chem. Soc. A,
1971, 2376–2382.
10 F. R. Lemke and C. Chaitheerapapkul, Polyhedron, 1996, 15,
2559.
15 A. L. Osipov, D. V. Gutsulyak, L. G. Kuzmina, J. A. K. Howard, D. A.
Lemenovskii, G. Suess-Fink and G. I. Nikonov, J. Organomet. Chem.,
2007, 692, 5081.
16 H. Sakaba, T. Hirata, C. Kabuto and K. Kabuto, J. Organomet. Chem.,
2007, 692, 402–407.
17 IHI consists in electron density transfer from the s(M–H) bonding
orbital to the s*(Si–X) antibonding orbital. This results in the
elongation of the M–H and Si–X bonds and contraction of the
M–Si bond (ref. 11–13).
11 (a) G. I. Nikonov, L. G. Kuzmina and J. A. K. Howard, J. Chem. Soc.,
Dalton Trans., 2002, 3037; (b) V. I. Bakhmutov, J. A. K. Howard, D. A.
Keen, L. G. Kuzmina, M. A. Leech, G. I. Nikonov, E. V. Vorontsov
and C. C. Wilson, J. Chem. Soc., Dalton Trans., 2000, 1631; (c) G. I.
Nikonov, L. G. Kuzmina, S. F. Vyboishchikov, D. A. Lemenovskii and
J. A. K. Howard, Chem.-Eur. J., 1999, 5, 2497; (d) K. Yu. Dorogov,
E. Dumont, N.-N. Ho, A. V. Churakov, L. G. Kuzmina, J.-M. Poblet,
A. J. Schultz, J. A. K. Howard, R. Bau, A. Lledos and G. I. Nikonov,
Organometallics, 2004, 23, 2845; (e) S. K. Ignatov, N. H. Rees, B. R.
Tyrrell, S. R. Dubberley, A. G. Razuvaev, P. Mountford and G. I.
Nikonov, Chem.-Eur. J, 2004, 10, 4991.
12 (a) S. R. Dubberley, S. K. Ignatov, N. H. Rees, A. G. Razuvaev, P.
Mountford and G. I. Nikonov, J. Am. Chem. Soc., 2003, 125, 644;
(b) G. I. Nikonov, P. Mountford and S. R. Dubberley, Inorg. Chem.,
2003, 42, 58; (c) G. I. Nikonov, P. Mountford, S. K. Ignatov, J. C. Green,
P. A. Cooke, M. A. Leech, L. G. Kuzmina, A. G. Razuvaev, N. H. Rees,
A. J. Blake, J. A. K. Howard and D. A. Lemenovskii, Dalton Trans.,
2001, 2903; (d) S. K. Ignatov, A. A. Merkoulov, S. R. Dubberley, A. R.
18 Donating phosphines strengthen the IHI by making the hydrides more
basic4b.
19 M. I. Bruce and N. J. Windsor, Aust. J. Chem., 1977, 30, 1601.
20 M. P. Gamasa, J. Gimeno, C. Gonzalez-Bernardo, B. M. Martin-Vaca,
D. Monti and M. Bassetti, Organometallics, 1996, 15, 302–308.
21 G. J. Baired, S. G. Davies, S. D. Moon, S. J. Simpson and R. H. Jones,
J. Chem. Soc., Dalton Trans., 1985, 1479.
22 SAINT, Version 6.02A, Bruker AXS Inc., Madison, Wisconsin, USA,
2001.
23 SHELXTL-Plus, Release 5.10, Bruker AXS Inc., Madison, Wisconsin,
USA, 1997.
6850 | Dalton Trans., 2008, 6843–6850
This journal is
The Royal Society of Chemistry 2008
©