Preparation of hydride complexes of ruthenium with bidentate phosphite ligands

Article abstract of DOI:10.1016/j.jorganchem.2007.09.007

Hydride complex RuH₂(PFFP)₂ (1) [PFFP = (CF₃CH₂O)₂PN(CH₃)N(CH₃ )P(OCH₂CF₃)₂] was prepared by allowing the compound RuCl₄(bpy) · H

Full text of DOI:10.1016/j.jorganchem.2007.09.007

Available online at www.sciencedirect.com
Journal of Organometallic Chemistry 692 (2007) 5481–5491
www.elsevier.com/locate/jorganchem
Preparation of hydride complexes of ruthenium
with bidentate phosphite ligands
a,
a
a
a
a
*
´
´
´
´
´
Jorge Bravo , Jesus Castro , Soledad Garcıa-Fontan , M Carmen Rodrıguez-Martınez ,
b,
b
b
Gabriele Albertin *, Stefano Antoniutti , Alessandro Manera
a
Departamento de Quı´mica Inorga´nica, Universidade de Vigo, Facultade de Quı´mica, Edificio de Ciencias Experimentais, 36310 Vigo (Galicia), Spain
b
`
Dipartimento di Chimica, Universita Ca’ Foscari Venezia, Dorsoduro, 2137, 30123 Venezia, Italy
Received 24 July 2007; received in revised form 6 September 2007; accepted 6 September 2007
Available online 14 September 2007
Abstract
Hydride complex RuH2(PFFP)2 (1) [PFFP = (CF3CH2O)2PN(CH3)N(CH3)P(OCH2CF3)2] was prepared by allowing the compound
RuCl4(bpy) Æ H2O (bpy = 1,2-bipyridine) to react first with the phosphite PFFP and then with NaBH4. Chloro-complex RuCl2(PFFP)2
(2) was also prepared, either by reacting RuCl4(bpy) Æ H2O with PFFP and zinc dust or by substituting triphenylphosphine with PFFP in
the precursor complex RuCl2(PPh3)3. Hydride derivative RuH2(POOP)2 (3) (POOP = Ph2POCH2CH2OPPh2) was prepared by reacting
compound RuCl3(AsPh3)2(CH3OH) first with the phosphite POOP and then with NaBH4. Depending on experimental conditions, treat-
ment of carbonylated solutions of RuCl3 Æ 3H2O with POOP yields either the cis- or trans-RuCl2(CO)(PHPh2)(POOP) (4) derivative.
Reaction of both cis- and trans-4 with LiAlH4 in thf affords dihydride complex RuH2(CO)(PHPh2)(POOP) (5). Chloro-complex all-
trans-RuCl2(CO)2(PPh2OMe)2 (6) was obtained by reacting carbonylated solutions of RuCl3 Æ 3H2O in methanol with POOP. Treatment
of chloro-complex 6 with NaBH4 in ethanol yielded hydride derivative all-trans-RuH2(CO)2(PPh2OMe)2 (7). The complexes were
characterised spectroscopically and the X-ray crystal structures of complexes 1, 3, cis-4 and 6 were determined.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Ruthenium; Carbonyl complexes; Hydride complexes; Bidentate phosphites
1. Introduction
mental point of view and in an attempt to activate molec-
ular hydrogen by coordination with an appropriate Ru
fragment.
Numerous studies over the past 30 years have acknowl-
edged the important role played by hydride complexes of
ruthenium in catalysing many reactions [1–3]. Among
these, the catalytic hydrogenation of unsaturated organic
molecules is important in both academic and industrial
research, and has proven particularly useful for many syn-
theses [4,5].
Mono- and bidentate phosphine ligands have been
widely used as ancillary ligands [1–3,6] in ruthenium
hydride chemistry, and systematic studies have shown
how both the electronic and steric properties of the phos-
phine ligand are important in determining the properties
of the hydride derivatives [1–7]. In this context, although
a large number of phosphines have been used to prepare
hydride complexes of ruthenium, we have found no exam-
ples containing bidentate phosphite (RO)2P(R1–R1)P(OR)2
or R2PO(CH2)nOPR2 ligands [R, R2 = alkyl or aryl;
R1 = CH2, NCH3; n = 2,3].
Non-classical hydride complexes [Ru]-g2-H2 have also
been comprehensively investigated [6], both from a funda-
*
Corresponding authors.
We are interested in the chemistry of classical and non-
classical hydride complexes of transition metals, and have
E-mail addresses: jbravo@uvigo.es (J. Bravo), albertin@unive.it (G.
Albertin).
0022-328X/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.09.007

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J. Bravo et al. / Journal of Organometallic Chemistry 692 (2007) 5481–5491
reported [8] the synthesis and reactivity of hydride com-
plexes containing both mono- and bidentate phosphite as
ancillary ligands. Now we have extended our studies to
include ruthenium as a central metal, and report here the
synthesis of some new hydride complexes stabilised by
bidentate phosphite ligands.
to dryness to give an oil which was triturated with ethanol
(3 mL). By slow cooling of the resulting solution to
ꢀ25 ꢁC, pale yellow crystals separated out, which were col-
lected by filtration and dried under vacuum; yield P25%.
Anal. Calc. for C20H30F24N4O8P4Ru: C, 21.16; H, 2.66;
1
N, 4.93. Found: C, 21.02; H, 2.75; N, 4.90%. H NMR
(CD2Cl2, 300 MHz) d (ppm): ꢀ9.67 (dt, 2H, JHP = 23 Hz,
RuH), 2.45 (m), 2.83 (d) (12H, CH3), 3.80–5.00 (m, 16H,
CH2). 31P{1H} NMR (CD2Cl2, 121.5 MHz) d (ppm):
A2B2 spin system, dA 203.6, dB 189.4, JAB = 39.3 Hz.
2. Experimental
2.1. General comments
All experimental manipulations were carried out under
argon using standard Schlenk techniques. All solvents were
dried over appropriate drying agents [9], degassed on a vac-
uum line, and distilled into vacuum-tight storage flasks.
RuCl3 Æ 3H2O was an Aldrich product, used as received.
The ligands 1,2-bis(diphenylphosphanyloxy)ethane [10]
(POOP) and 1,2-bis[di(2,2,2-trifluoroethoxy)phosphino]-
1,2-dimethylhydrazine [11] (PFFP) were prepared using
published methods. 1H and 31P NMR spectra were
recorded in CDCl3 or CD2Cl2 on Bruker ARX-400 or Bru-
ker AVANCE 300 spectrometers, using the solvent as
2.2.2. RuCl2(PFFP)2 (2)
Method 1: An excess of zinc dust (10 mmol, 0.65 g) was
added to a solution of RuCl4(bpy) Æ H2O (1 mmol, 0.42 g)
in 20 mL of toluene containing a slight excess of the phos-
phine PFFP (2.1 mmol, 1.08 g). The reaction mixture was
stirred for 3 h, ethanol (20 mL) was added and the suspen-
sion was stirred for 20 h. The solvent was removed by evap-
oration under reduced pressure to give an oil from which
the chloro-complex was extracted with three 5-mL portions
of toluene. The extracts were evaporated to dryness to give
an oil which was triturated with ethanol (3 mL). An orange
solid slowly separated out, which was filtered and dried
under vacuum; yield P20%.
Method 2: A slight excess of the phosphine PFFP
(1 mmol, 0.42 g) was added to a solution of RuCl2(PPh3)3
(0.48 mmol, 0.46 g) in 15 mL of toluene and the reaction
mixture was stirred for 3 h. The solvent was removed under
reduced pressure to give an oil which was triturated with
ethanol (3 mL). A yellow-orange solid slowly separated
out, which was filtered. By fractional crystallisation from
CH2Cl2 and ethanol, orange microcrystals of the complex
were obtained; yield P45%.
1
internal lock. H signals were referred to internal TMS,
while 31P{1H} were referred to 85% H3PO4 with downfield
considered positive. Spin-lattice relaxation times T1 were
determined at various temperatures in deuterated dichloro-
methane by the inversion-recovery method using a stan-
dard 180ꢁ–s–90ꢁ pulse sequence and 16 different values of
s at each temperature. The HMBC NMR experiments were
performed using its standard program. The GNMR [12] and
INMR [13] software packages were used to treat NMR data.
IR spectra of samples in KBr pellets were obtained on Bru-
ker Vector IFS28 or Perkin–Elmer Spectrum One FT spec-
trometers. Mass spectra were recorded on a Micromass
Autospec M LSIMS (FAB+) system with 3-nitrobenzyl
alcohol as matrix. Microanalyses were carried out on a
Fisons EA-1108 apparatus.
Anal. Calc. for C20H28Cl2F24N4O8P4Ru: C, 19.95; H,
2.34; Cl, 5.89; N, 4.65. Found: C, 19.78; H, 2.45; Cl,
1
5.70; N, 4.59%. H NMR (CD2Cl2, 300 MHz) d (ppm):
3.10 (t, 12H, JHP = 2 Hz, CH3), 4.60 (m, 16H, CH2).
31P{1H} NMR (CD2Cl2, 121.5 MHz) d (ppm): 157.8 (s).
2.2. Synthesis of complexes
2.2.3. RuH2(POOP)2 (3)
(POOP = Ph2POCH2CH2OPPh2)
The complexes RuCl4(bpy) Æ H2O (bpy = 2,20-bipyri-
dine), RuCl2(PPh3)3 and RuCl3(AsPh3)2(CH3OH) were
prepared following the method previously reported [14–16].
An excess of the phosphite POOP (0.76 g, 1.76 mmol) in
toluene (6 mL) was added to a solution of RuCl3(AsPh3)2-
(MeOH) (0.50 g, 0.59 mmol) in 20 mL of toluene and the
reaction mixture was stirred at room temperature for 1 h.
The orange-red solution obtained was filtered and 0.058 g
(1.53 mmol) of NaBH4 dissolved in 5 mL of ethanol were
added. The yellow mixture was stirred for 1 h and then fil-
tered. The solvent was evaporated off under vacuum and
the solid obtained dissolved in CH2Cl2. The solution was
stirred for 10 min and precipitation was induced by the
addition of 5 mL of diethylether. The white solid obtained
was filtered off and recrystallised from ethanol giving suit-
able crystals for an X-ray diffraction study; yield P44%.
Anal. Calc. for C52H50O4P4Ru: C, 64.79; H, 5.23. Found:
C, 63.99; H, 5.18%. IR (cmꢀ1): 1910 (m), 1879 (m) m(Ru–
2.2.1. RuH2(PFFP)2 (1) [PFFP =
(CF3CH2O)2PN(CH3)N(CH3)P(OCH2CF3)2]
An excess of PFFP (1.5 g, 2.9 mmol) was added to a
solution of RuCl4(bpy) Æ H2O (1.10 mmol, 0.46 g) in 5 mL
of toluene and the resulting solution was stirred for 1 h.
An excess of NaBH4 (10 mmol, 0.38 g) in 20 mL of ethanol
was added and the reaction mixture was stirred at 0 ꢁC for
4 h. The solvent was removed under reduced pressure to
give an oil from which the hydride complex was extracted
with three 10-mL portions of CH2Cl2. The extracts were
evaporated to dryness to give an oil from which the hydride
complex was extracted again with three 10-mL portions of
petroleum ether (40–60 ꢁC). The extracts were evaporated
1
H). H NMR (CDCl3, 400 MHz) d (ppm): ꢀ8.30 (m, 2H,

J. Bravo et al. / Journal of Organometallic Chemistry 692 (2007) 5481–5491
5483
Ru–H), 2.40 (m, 2H, CH2), 3.09 (m, 2H, CH2), 3.29 (m,
2H, CH2), 3.42 (m, 2H, CH2), 6.60–8.00 (m, 40H, Ph).
31P{1H} NMR (CDCl3, 161 MHz) d (ppm): A2B2 spin sys-
tem, dA 155.4, dB 157.7, JAB = 27.1 Hz. FAB MS: m/z
(referred to the most abundant isotopes) 962 [Mꢀ2H].
C39H37O3P3Ru: C, 62.65; H, 4.99. Found: C, 62.15; H,
5.10%. IR (cmꢀ1): 2360 (w) m(PH), 1963 (s) m(CO), 1832
(m) m(Ru–H). 1H NMR (CD2Cl2, 400 MHz) d (ppm):
ꢀ7.80 (ddd, 1H, Ru–H), ꢀ7.40 (dtd, 1H, Ru–H, Jcis = 25,
Jtrans = 76, JHH = 3 Hz), 4.06 (m, 3H, CH2), 4.28 (m, 1H,
CH2), 5.44 [dm, 1H (PHPh2), JHP = 336 Hz], 7.00–8.20
(m, 30H, Ph). 31P{1H} NMR (CD2Cl2, 161 MHz) d
(ppm): ABM spin system, dM 38.7 (PHPh2), dA 154.9, dB
156.9, JAB = 29.7, JAM = 15.8, JBM = 254.6 Hz. FAB
MS: m/z (referred to the most abundant isotopes) 746
[M], 718 [MꢀCO].
2.2.4. trans-RuCl2(CO)(PHPh2)(POOP) (trans-4)
A solution of RuCl3 Æ 3H2O (0.150 g, 0.57 mmol) in thf
(20 mL) was allowed to stand under a CO atmosphere
(1 atm) and refluxed for 1 h. The resulting orange solution
was cooled to room temperature and a toluene solution of
POOP (2.460 mmol, 1.06 g in 8 mL) was added. The mix-
ture was stirred for 24 h and then the solvent was removed
under vacuum. The resulting oily residue was treated with
methanol (2 mL) obtaining a yellow solid that was filtered
off and crystallised from methanol; yield P34%. Anal.
Calc. for C39H35Cl2O3P3Ru: C, 57.36; H, 4.32. Found: C,
57.26; H, 4.32%. IR (cmꢀ1): 320 (m) m(Ru–Cl), 1994 (s)
2.2.7. all-trans-RuCl2(CO)2(PPh2OMe)2 (6)
CO was bubbled for 30 min through a refluxing solution
of RuCl3 Æ 3H2O (0.150 g, 0.723 mmol) in MeOH (20 mL).
A colour change from orange to dark blue was observed.
The solution was then cooled to room temperature, an
excess of POOP (0.93 g, 2.180 mmol) was added and the
mixture was stirred for 24 h. The resulting yellow precipi-
tate was filtered off and crystallised from methanol. From
the mother liquor, yellow crystals suitable for X-ray crys-
tallography were isolated, yield P23%. Anal. Calc. for
C28H26Cl2O4P2Ru: C, 50.91; H, 3.97. Found: C, 51.31;
H, 3.83%. IR (cmꢀ1): 330 (w) mas(Ru–Cl), 2015 (s) m(CO).
1H NMR (CDCl3, 400 MHz) d (ppm): 3.55 (vt, 6H, CH3,
Jvt = 6.4 Hz), 7.40 (m, 12H, Ph), 7.80 (m, 8H, Ph).
31P{1H} NMR (CDCl3, 161 MHz) d (ppm): 120.1 [s, 2P,
PPh2(OMe)]. FAB MS: m/z (referred to the most abundant
isotopes) 660 [M], 604 [Mꢀ2CO], 597 [Mꢀ{CO,Cl}].
1
m(CO), 2380 (w) m(P–H). H NMR (CDCl3, 400 MHz) d
(ppm): 4.10 (m, 4H, CH2), 5.65 (dm, 1H, PHPh2,
JHP = 369 Hz), 7.00–7.80 (m, 30H, Ph). 31P{1H} NMR
(CDCl3, 161 MHz) d (ppm): 15.4 (dd, 1P, PHPh2,
Jtrans = 334, Jcis = 35 Hz), 118.6 (dd, 1P, Jcis = 43 and
35 Hz), 134.2 (dd, 1P, Jcis = 43, Jtrans = 334 Hz). FAB
MS: m/z (referred to the most abundant isotopes) 816
[M], 781 [MꢀCl].
2.2.5. cis-RuCl2(CO)(PHPh2)(POOP) (cis-4)
The complex was obtained following the same method
used for trans-4 but adding the phosphine POOP to a boil-
ing carbonylated solution of RuCl3 Æ 3H2O in thf. Recrys-
tallization from a CH2Cl2 solution of the solid obtained
gave suitable crystals for an X-ray diffraction study; yield
P48%. Anal. Calc. for C39Cl2H35P3O3Ru: C, 57.36; H,
4.32. Found: C, 58.28; H, 4.32%. IR (cmꢀ1): 270 (w)
ms(Ru–Cl), 299 (w) mas(Ru–Cl), 1981 (s) m(CO), 2350 (w)
2.2.8. all-trans-RuH2(CO)2(PPh2OMe)2 (7)
To a solution of complex RuCl2(CO)2(PPh2OMe)2 (6)
(0.100 g, 0.151 mmol) in toluene (15 mL) an excess of
NaBH4 (0.180 g, 4.75 mmol) in ethanol (10 mL) was
added. The mixture was stirred at room temperature for
12 h and then the solution was evaporated to dryness.
From the residue obtained the hydride was extracted with
three 5-mL portions of CH2Cl2. The extracts were evapo-
rated to dryness and the oil obtained was triturated with
ethanol (5 mL). An orange solid slowly separated out
which was filtered and crystallised from ethanol; yield
P44%. Anal. Calc. for C28H28O4P2Ru: C, 56.85; H, 4.77.
Found: C, 56.69; H, 4.70%. IR (cmꢀ1): 1972 (vs) m(CO),
1
m(P–H). H NMR (CD2Cl2, 400 MHz) d (ppm): 4.00 (m,
1H, CH2), 4.20 (m, 2H, CH2), 5.20 [ddd, 1H (PHPh2),
3
1JHP = 363, JHP = 3 and 6 Hz], 5.40 [m, 1H, CH2 (L)],
7.20–8.40 (m, 30H, Ph). 31P{1H} NMR (CD2Cl2,
161 MHz) d (ppm): 15.8 [dd, 1P(PHPh2), Jtrans = 375,
Jcis = 21 Hz], 115.0 (dd, 1P, Jtrans = 375, Jcis = 32 Hz),
139.9 (dd, 1P, Jcis = 32, Jcis = 21 Hz). FAB MS:m/z
(referred to the most abundant isotopes) 781 [MꢀCl].
1
2023 (s) m(Ru–H). H NMR (CDCl3, 400 MHz) d (ppm):
ꢀ7.63 (t, 2H, Ru–H, JHP = 23 Hz), 3.53 (vt, 6H, CH3,
2.2.6. cis-RuH2(CO)(PHPh2)(POOP) (5)
Jvt = 7 Hz), 7.31 (m, 12H, Ph), 7.71 (m, 8H, Ph). 31P{1H}
To a solution of complex trans-RuCl2(CO)(PHPh2)-
(POOP) (trans-4) (0.150 g, 0.183 mmol) in thf (20 mL), an
excess of LiAlH4 (0.070 g, 1.83 mmol) was added. The
reaction mixture was stirred for 5 h at room temperature,
filtered through celite and then evaporated to dryness.
After adding CH2Cl2 to the solid obtained, the mixture
was filtered again and the resulting yellow solution was
evaporated to dryness. Addition of methanol and stirring
for a whole night resulted in the formation of a white pre-
cipitate, which was filtered off, washed with methanol and
crystallised from methanol; yield P40%. Anal. Calc. for
NMR (CDCl3, 161 MHz) d (ppm): 155.3 [s, 2P,
P(OMe)Ph2]. FAB MS:m/z (referred to the most abun-
dant isotopes) 591 [MꢀH], 562 [Mꢀ{CO,2H}], 534 [Mꢀ
{2CO,2H}].
2.2.9. X-ray crystallography of compounds 1, 3, cis-4 and 6
Single crystals of compounds 1, 3, cis–4 and 6 were
mounted on a glass fibre and studied in a SIEMENS Smart
CCD area-detector diffractometer using graphite-mono-
˚
chromated Mo Ka radiation (k = 0.71073 A). For com-
pounds 1, cis-4 and 6 the studies were carried out at

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J. Bravo et al. / Journal of Organometallic Chemistry 692 (2007) 5481–5491
room temperature but, for compound 3, the data collection
was made at ꢀ100 ꢁC, in order to avoid the disorder
expected for dihydride complexes. Absorption corrections
were carried out using SADABS [17]. The crystallographic
calculations were performed with the OSCAIL program
[18]. All the structures were solved by direct methods and
refined by full-matrix least-squares based on F2 [19]. All
non-hydrogen atoms were refined with anisotropic dis-
placement parameters. The SQUEEZE program was used with
the data from 3 to correct the reflection data for the diffuse
scattering due to disordered solvent [20]. In all cases the
hydrogen atoms were included in idealised positions and
refined with isotropic displacement parameters, except for
the hydride ligand in 3 and that of the phosphine ligand
in 6 which were located on a difference electron density
map but no refined. Atomic scattering factors and anoma-
lous dispersion corrections for all atoms were taken from
International Tables for X-ray Crystallography [21].
exc. PFFP
Zn dust
Cl
"RuCl4(bpy)• H2O"
RuCl2(PPh3)3
P
P
P
H-
Ru
1
P
exc. PFFP
Cl
2 ( II )
Scheme 2.
Treatment of dichloro-complexes 2 with NaBH4 or
LiAlH4 in different conditions did not give the related dihy-
dride 1. Also the reaction of RuCl2(PFFP)2 (2) with H2 in
the presence of base (LiOH or NEt3) did not give the dihy-
dride, and the starting dichloro-complex 2 was the only iso-
lated product. Any other attempt to obtain 1 from the
dichloro-species 2 failed, and it therefore seems that only
the direct reaction of RuCl4(bpy) Æ H2O first with PFFP
and then with NaBH4 (Scheme 1) does allow the preparation
of the dihydride complex of ruthenium 1 with 1,2-bis(alk-
oxyphosphine)-1,2-dimethylhydrazine (PFFP) ligand.
A different precursor was instead used to prepare the
dihydride complex RuH2(POOP)2 (3), containing the 1,2-
bis(diphenylphosphanyloxy)ethane (POOP) as supporting
ligand (Scheme 3).
Treatment of the arsine complex RuCl3(AsPh3)2-
(MeOH) [16], first with an excess of POOP and then with
NaBH4 in ethanol, gives dihydride 3 as white microcrystals
in moderate yield. It therefore seems that the synthesis of
dihydrides with bidentate phosphites like 1 and 3 requires
the use of precursors in a high oxidation state [Ru(III)]
whose reduction, in the presence of NaBH4, allows coordi-
nation of the Hꢀ ligand, to yield the final hydride
complexes.
Both dihydrides RuH2(PFFP)2 (1) and RuH2(POOP)2
(3) are crystalline, pale orange (1) or white (3) solids, stable
in air and in solution of common organic solvents, where
they behave as non-electrolytes. Analytical and spectro-
scopic data support the proposed formulation, which was
further confirmed by X-ray crystal structure determination
(Figs. 1 and 2).
Compound 1 consists of a ruthenium atom site on a
symmetry centre, coordinated by two P,P0-donor biden-
tate ligands and two hydride ligands, which do not appear
in the X-ray solution, probably due to the well known
limitations of this technique for light atoms in the vicinity
of heavy transition metals, the poor quality of the crystal
obtained, and the number of disordered atoms. However,
the spectroscopic data and coordination polyhedron fit
3. Results and discussion
3.1. Hydride complexes with bidentate phosphites
The synthesis of dihydride complex RuH2(PFFP)2 (1),
with 1,2-bis(ditrifluoroethoxyphosphine)-1,2-dimethylhy-
drazine (PFFP) as supporting ligand, was achieved by
reacting chloro-complex RuCl4(bpy) Æ H2O [14a,14b] with
an excess of phosphite, followed by treatment with NaBH4
in ethanol, as shown in Scheme 1.
The use of RuCl4(bpy) Æ H2O as a precursor seems to be
crucial for successful synthesis, because the reaction of
dichloro-complex RuCl2(PFFP)2 (2) with NaBH4, or other
hydrurating agents, did not give the expected dihydride 1.
Not even the Grubbs method [22] can be used owing to
the decomposition of the phosphite.
Ru(II) dichloro-complex RuCl2(PFFP)2 (2) was pre-
pared following two different methods, involving either
reaction of RuCl4(bpy) Æ H2O with the diphosphine PFFP
in the presence of zinc dust, or substitution of PPh3 in
the RuCl2(PPh3)3 precursor, as shown in Scheme 2.
Zinc dust is needed for reducing the ruthenium central
metal to give RuCl2(PFFP)2 (2) using RuCl4(bpy) Æ H2O
as
a
precursor. Instead, substitution of PPh3 in
RuCl2(PPh3)3 is easy with PFFP and gives 2 in reasonable
yields.
P
H
H
P
exc. PFFP
NaBH4
P
"RuCl4(bpy)•H2O"
Ru
H
H
P
P
exc. POOP
exc. NaBH4
RuCl3(AsPh3)2(MeOH)
Ru
P
P
1 ( I )
P
P—P = (CF3CH2O)2PN(CH3)N(CH3)P(OCH2CF3)2 (PFFP)
3 ( III )
P—P = Ph2POCH2CH2OPPh2 (POOP)
bpy = 1,2-bipyridine
Scheme 1.
Scheme 3.

J. Bravo et al. / Journal of Organometallic Chemistry 692 (2007) 5481–5491
5485
P,P-dimethyldiphosphinehydrazine ligands [25], partly
due to the oxidation state of the metal and partly to the dif-
ferent type of phosphorus ligand (see Table 2).
The P–N bond distances in the hydrazine ligand are
˚
1.684(9) and 1.736(9) A, and are similar to those found
for other Ru(II) complexes [24]. The shorter one corre-
sponds to longer Ru–P bond lengths and N(11) atom.
Angles around N(11) total 360ꢁ, and this fits the sp2charac-
ter for this atom, due to the important double bond nature
of the P–N bond. A different environment is found around
the N(12) atom, since the sum of angles is 334.0ꢁ, and the
N(12)–P bond should be considered as single. Another con-
sequence of those features is the planarity of the chelate
ring, essentially planar except for the N(12) atom,
˚
0.52(1) A out of the plane [r.m.s. = 0.0454, if N(12) is not
considered]. These facts have been already reported for
tungsten(0) complexes [26] in a different way from that
which occurs with Pd and Pt complexes, in which the whole
chelate is essentially planar [26,27]. The N–N bond length
1.36(1) is, however, shorter than that found for Ru(II)
complexes with similar ligands [24].
Fig. 1. Molecular structure of RuH2(PFFP)2 (1). The atoms are drawn at
30% probability level. The trifluoroethyl groups and the hydrogen atoms
of the methyl groups have not been drawn.
The molecular structure of RuH2(POOP)2 (3), including
the atom-numbering scheme of the complex, is shown in
Fig. 2. Table 3 lists some selected bond lengths and angles.
The compound consists of molecular units without intra-
molecular interactions other than weak, non-classic, hydro-
gen bonds. Four phosphorus atoms and one hydride ligand
coordinate the Ru atom in a square pyramidal fashion. The
basal plane, formed of three phosphorus atoms and the
hydride ligand, has an r.m.s. of 0.0668, with a maximum
˚
˚
deviation of 0.08(3) A. The ruthenium atom is 0.30(2) A
out of plane in the direction of the other phosphorus atom.
1
However, H NMR spectroscopy indicates the presence of
a second hydride ligand, but its position was not deter-
mined by X-ray diffraction. This second hydride ligand
should be in a cis position with respect to the other hydride
ligand, and the geometrical parameters are in good agree-
ment with these statements, since the four Ru–P distances
are grouped in two pairs. Ru–P(4) and Ru–P(1) are around
Fig. 2. Molecular structure of compound RuH2(POOP)2 (3) with 30%
probability ellipsoids.
˚
˚
2.27 A [2.276(2) and 2.277(2) A], and are in trans position
to each other, but Ru–P(2) and Ru–P(3) are around
˚
˚
the proposed formulation. In this sense, the polyhedron
may be considered as an octahedron, with the P,P0-biden-
tate ligands occupying four coordinating sites, and the
hydride atoms two mutually cis positions, on the coordi-
nation sphere. Both chelate angles (symmetry related) are
80.26(10)ꢁ, more acute than the theoretical 90ꢁ for an
octahedral coordinating sphere and an important source
of distortion. Only other two cis angles (apart from the
chelate ones) are known, and range from 101.2(1)ꢁ to
103.6(1)ꢁ, not far from the theoretical 90ꢁ. Only one trans
angles is known, 174.04(14)ꢁ, not far from the theoretical
180ꢁ.
2.31 A [2.305(2) and 2.313(2) A], reflecting the trans influ-
ence of the hydride ligands. These Ru–P distances are well
within the expected range for dihydride Ru2+ complexes
(see Table 1) [7b,28].
The IR spectra of RuH2(PFFP)2 (1) show the band
characteristic of the phosphine PFFP but none attributable
to the mRuH of the hydride ligand. However, the presence of
1
this ligand is confirmed by the H NMR spectra, which
show one doublet of triplets at ꢀ9.67 ppm, characteristic
of hydride ligands, coupled to the phosphorus nuclei of
the phosphites, which are two-by-two magnetically equiva-
lent. The 31P spectrum, in fact, is an A2B2 multiplet, simu-
lated with the parameters reported in Experimental. On the
basis of these data, a cis geometry I like that observed in
the solid state (Fig. 1) may be proposed for hydride com-
plex 1.
˚
The Ru–P bond distances, 2.238(2) and 2.248(3) A, are
similar to those found for other phosphite or phosphonite
Ru(II) complexes [23,24] and, as expected, they are shorter
than those found for other ruthenium(0) complexes with

5486
J. Bravo et al. / Journal of Organometallic Chemistry 692 (2007) 5481–5491
Table 1
Crystal data and structure refinement for compounds 1, 3, cis-4 and 6
Identification code
Empirical formula
Formula weight
Temperature (K)
1
3
cis-4
C39H34Cl2O3P3Ru
815.54
293(2)
0.71073
6
C20H30F24N4O8P4Ru
1135.43
293(2)
0.71073
Monoclinic
C2/c
C52H48O4P4Ru
961.85
173(2)
0.71073
Triclinic
P1
C28H26Cl2O4P2Ru
660.40
293(2)
0.71073
Monoclinic
C2/c
˚
Wavelength (A)
Crystal system
Space group
Unit cell dimensions
Monoclinic
P21/c
ꢀ
˚
a (A)
12.0730(12)
18.6061(18)
18.8583(19)
90
93.483(2)
90
4228.3(7)
4
1.784
0.672
12.903(3)
13.133(3)
17.171(4)
80.969(4)
70.198(4)
84.765(5)
2701.3(10)
2
1.183
10.3012(9)
27.296(2)
12.9737(11)
90
100.676(2)
90
3584.8(5)
16.191(2)
9.0599(13)
20.132(3)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
90
102.836(3)
90
2879.3(7)
3
˚
Volume (A )
Z
4
4
Dcalc (Mg/m3)
Absorption coefficient (mmꢀ1
F(000)
1.511
0.758
1660
1.523
0.873
1336
)
0.447
992
2248
Crystal size
H Range for data collection
Index ranges
0.33 · 0.23 · 0.20 mm
2.01–28.01ꢁ
ꢀ12 6 h 6 15;
ꢀ22 6 k 6 24;
ꢀ24 6 l 6 24
11884
4779 [R(int) = 0.0748]
2201
0.933
0.28 · 0.24 · 0.08 mm
1.27–28.20ꢁ
ꢀ16 6 h 6 17;
ꢀ17 6 k 6 16;
ꢀ21 6 l 6 22
15129
10679 [R(int) = 0.0816]
3597
0.802
0.50 · 0.40 · 0.20 mm
1.49–28.02ꢁ
ꢀ12 6 h 6 13;
ꢀ33 6 k 6 35;
ꢀ17 6 l 6 17
20862
8156 [R(int) = 0.0637]
4114
0.941
0.40 · 0.35 · 0.29 mm
2.08–28.00ꢁ
ꢀ16 6 h 6 21;
ꢀ11 6 k 6 9;
ꢀ26 6 l 6 24
8568
3330 [R(int) = 0.0278]
2696
0.959
Reflections collected
Independent reflections
Reflections observed (>2r)
Data completeness
Absorption correction
Semi-empirical from
equivalents
1.000 and 0.714
Full-matrix least-squares
on F2
Semi-empirical from
equivalents
1.000 and 0.663
Full-matrix least-squares
on F2
Semi-empirical from
equivalents
1.000 and 0.904
Full-matrix least-squares
on F2
Semi-empirical from
equivalents
1.000 and 0.841
Full-matrix least-squares
on F2
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
R indices (all data)
4779/19/231
0.987
10679/0/540
0.734
8156/0/433
0.803
3330/0/170
1.000
R1 = 0.1089 wR2 = 0.2954 R1 = 0.0687 wR2 = 0.1376 R1 = 0.0450 wR2 = 0.0632 R1 = 0.0305 wR2 = 0.0759
R1 = 0.1830 wR2 = 0.3330 R1 = 0.1805 wR2 = 0.1595 R1 = 0.1271 wR2 = 0.0741 R1 = 0.0420 wR2 = 0.0790
Largest diffraction peak and hole 1.433 and ꢀ0.913
0.873 and ꢀ0.549
0.810 and ꢀ0.357
0.369 and ꢀ0.332
ꢀ3
˚
(e A
)
Table 2
Table 3
˚
˚
Bond lengths (A) and angles (ꢁ) for RuH2(PFFP)2 (1)
Bond lengths (A) and angles (ꢁ) for compound 3
Lengths
Ru–P(2)
Ru–P(1)
P(1)–O(2)
P(1)–N(11)
N(11)–N(12)
Lengths
2.238(2)
2.248(3)
1.620(8)
1.684(9)
1.358(12)
Ru–P(2i)
Ru–P(1i)
P(1)–O(1)
P(2)–N(12)
2.238(2)
2.248(3)
1.635(7)
1.736(9)
Ru–H(1)
Ru–P(1)
Ru–P(3)
1.68(7)
2.277(2)
2.313(2)
Ru–P(4)
Ru–P(2)
2.276(2)
2.305(2)
Angles
H(1)–Ru–P(4)
P(4)–Ru–P(1)
P(4)–Ru–P(2)
H(1)–Ru–P(3)
P(1)–Ru–P(3)
79(2)
H(1)–Ru–P(1)
H(1)–Ru–P(2)
P(1)–Ru–P(2)
P(4)–Ru–P(3)
P(2)–Ru–P(3)
80(2)
165(2)
92.76(8)
93.95(8)
96.42(8)
Angles
153.92(8)
103.14(8)
98(2)
P(2) –Ru–P(2i)1
P(2) –Ru–P(1)
O(2)–P(1)–O(1)
O(1)–P(1) –N(11)
O(1)–P(1)–Ru
O(4)–P(2)–N(12)
N(12)–N(11)–C(1)
N(12)–N(11)–P(1)
C(1)–N(11)–P(1)
174.04(14)
80.26(10)
95.6(5)
P(2)–Ru–P(1i)
P(1i)–Ru–P(1)
O(2)–P(1)–N(11)
O(2)–P(1)–Ru
O(3)–P(2)–O(4)
O(3)–P(2)–N(12)
C(2)–N(12)–P(2)
N(11)–N(12)–P(2)
N(11)–N(12)–C(2)
103.61(10)
101.25(15)
106.1(5)
122.1(4)
101.5(5)
98.5(5)
117.3(9)
106.3(6)
110.4(10)
i
104.80(8)
97.9(4)
123.2(3)
101.1(4)
116.9(9)
121.1(6)
122.0(8)
the dihydride ligands. At room temperature, the proton
spectrum displays a hydride multiplet at ꢀ8.30 ppm, which
broadens on lowering the sample temperature and gives
T1(min) values of 194 ms at 253 K (400 MHz), fitting the
classical nature [7a] of Hꢀ ligands.
Symmetry transformations used to generate equivalent atoms: 1 ꢀ x, y,
3/2 ꢀ z.
The 31P{1H} NMR spectrum of RuH2(POOP)2 (3) also
shows an A2B2 pattern, indicating the cis arrangement of
The IR spectrum shows two mRuH bands at 1910 and
1879 cmꢀ1, characteristic of the cis position [29] of the

J. Bravo et al. / Journal of Organometallic Chemistry 692 (2007) 5481–5491
5487
hydride ligands in a geometry III, like that observed in the
solid state (Fig. 2).
analytical and spectroscopic (IR, NMR) data, and by the
X-ray crystal structure determination of cis-RuCl2(CO)-
(PHPh2)(POOP) (cis-4).
Good analytical data were obtained for the chloro-com-
plex RuCl2(PFFP)2 (2), which is an orange solid, stable in
air and in solution of common organic solvents. The IR
spectra show the bands characteristic of the phosphite
ligand PFFP, whose presence is confirmed by the 1H
NMR spectrum, showing a triplet at 3.10 ppm of the
NCH3 protons and a multiplet at 4.60 ppm of the methy-
lene CF3CH2O hydrogen atoms. In the temperature range
between +20 and ꢀ80 ꢁC, the 31P{1H} NMR spectrum of 2
is a sharp singlet, suggesting the magnetic equivalence of
the four phosphorus nuclei of the two bidentate phosphite
ligands. On the basis of these data, a trans geometry II may
be proposed for dichloro-complex 2.
The molecular structure, including the atom-numbering
scheme, of the complex is shown in Fig. 3. Table 4 lists
some selected bond lengths and angles, and Table 5 some
intramolecular hydrogen interactions. There are no impor-
tant interactions between discrete molecules. The ruthe-
nium atom is coordinated by two phosphorus atoms of
the chelating bidentate phosphinite ligand, one phosphorus
atom of the diphenylphosphine ligand, two chloride ions
and one carbon atom of the carbonyl ligand, giving a core
[RuP3C1Cl2]. The chlorine ligands are in relative cis posi-
tions [Cl(1)–Ru–Cl(2) = 90.88(4)ꢁ]. The Ru–Cl bond
lengths do not show the expected differences, owing to
the different trans effect of the phosphinite and carbonyl
3.2. Hydride-carbonyl complexes
˚
ligands, the distances being 2.4532(11) and 2.4563(11) A,
respectively. The cis angles around the Ru atom vary from
84.93(4)ꢁ to 97.99(13)ꢁ, and the trans angles are 175.55(4)ꢁ,
174.38(12)ꢁ and 171.14(4)ꢁ. The major deviation from reg-
ularity seems to arise from repulsion between the H atom
of the phosphine and the p cloud of the neighbouring phe-
nyl ring (shown in Fig. 3 with dotted lines) [32]. The three
equatorial orthorhombic planes [dihedral angles of
89.93(4)ꢁ, 88.85(4)ꢁ and 85.55(4)ꢁ] contain the Ru atom
Treatment of a carbonylated solution (CO, 1 atm) of
RuCl3 Æ 3H2O in thf with an excess of the diphosphinite
Ph2POCH2CH2OPPh2 (POOP) gave, after workup, a yel-
low solid characterised as the chloro-carbonyl complex
trans-RuCl2(CO)(PHPh2)(POOP) (trans-4) (Scheme 4).
The carbonylated solution of RuCl3 Æ 3H2O probably con-
tains RuCl2(CO)3(solvent) or [RuCl2(CO)2]n species
[1a,30], which react with the bidentate phosphite to give
the final monocarbonyl complex 4.
Surprisingly, the reaction proceeds not only with the
coordination of POOP but also with the formation of the
secondary phosphine PHPh2, probably obtained by disrup-
tion of the POOP ligand. Metal-mediated disruption of the
Ph2POCH2CH2OPPh2 ligand to give a diphosphoxane
(POP) complex has been previously reported [8j,31] but,
in any case, the formation of a secondary phosphine had
been observed.
Complex 4 is stable in solution but slowly isomerises
both at room temperature and in refluxing thf, to give
the cis isomer (cis-4) which was isolated as a pale yellow
solid in high yield. The cis isomer can also be obtained
by reacting the carbonylated solution of RuCl3 Æ 3H2O with
phosphite POOP in refluxing thf.
Both the cis and trans isomers of complex RuCl2-
(CO)(PHPh2)(POOP) (4) are stable yellow (trans-4) or pale
yellow (cis-4) solids, soluble in common organic solvents
and non-electrolytes. Their formulation is supported by
Fig. 3. Molecular structure of cis-RuCl2(CO)(PHPh2)(POOP) (cis-4). The
atoms are drawn at 30% probability level.
Cl
Cl
CO
Cl
P
P
CO, thf
exc. POOP
i
RuCl3•3H2O
Ru
Ru
P
P
PHPh2
PHPh2
Cl
CO
trans-4 ( IV )
P—P = Ph2POCH2CH2OPPh2 (POOP)
cis-4 ( V )
i = either in CH2Cl2 solution at 25 °C for 6 days, or in refluxing thf for 1 hour
Scheme 4.

5488
J. Bravo et al. / Journal of Organometallic Chemistry 692 (2007) 5481–5491
Table 4
H
˚
Bond lengths (A) and angles (ꢁ) for cis-4
H
P
LiAlH4
thf
RuCl2(CO)(PHPh2)(POOP)
Ru
Lengths
cis-4 or trans-4
P
PHPh2
Cl(1)–Ru
Ru–C(1)
Ru–P(1)
2.4563(11)
1.885(5)
2.3456(11)
Cl(2)–Ru
Ru–P(2)
Ru–P(3)
2.4532(11)
2.3158(11)
2.4059(11)
CO
5 ( VI )
Angles
Scheme 5.
C(1)–Ru–P(2)
P(2)–Ru–P(1)
P(2)–Ru–P(3)
P(1)–Ru–Cl(2)
P(2)–Ru–Cl(1)
P(3)–Ru–Cl(1)
P(2)–Ru–Cl(2)
P(1)–Ru–P(3)
97.99(13)
93.27(4)
95.09(4)
84.93(4)
85.21(4)
88.79(4)
175.55(4)
171.14(4)
C(1)–Ru–P(1)
C(1)–Ru–P(3)
C(1)–Ru–Cl(2)
P(3)–Ru–Cl(2)
P(1)–Ru–Cl(1)
Cl(2)–Ru–Cl(1)
C(1)–Ru–Cl(1)
89.60(12)
86.33(12)
86.08(13)
86.94(4)
94.85(4)
90.88(4)
(5), which was isolated as a white solid and characterised
(Scheme 5) [33].
The IR spectrum of 5 shows one strong band at
1963 cmꢀ1, due to mCO, and one at 1832 cmꢀ1, attributable
to the stretching vibrations of the Ru–H bonds. Weak
absorption at 2360 cmꢀ1, due to the mPH of the secondary
phosphine PHPh2 [34], was also observed.
174.38(12)
In the high field of the proton NMR spectrum of 5, two
multiplets appear at ꢀ7.80 and ꢀ7.40 ppm, each integrat-
ing by one proton, and were attributed to two chemically
non-equivalent hydride ligands. As the 31P{1H} NMR
spectrum corresponds to that of an ABM system of the
mer arrangement of the three phosphorus nuclei, the
hydride pattern may be simulated [12] with an ABMXY
model (X, Y = 1H), with the parameters reported in Exper-
imental. The good fit between the calculated and experi-
mental spectra (Fig. 4) supports the proposed cis
attribution [29,35]. The classical hydridic nature of the
complex was also confirmed by T1 measurements, which
gave values of T1(min) of 373 and 419 ms, in agreement with
Table 5
˚
Hydrogen bonds parameters for cis-4 (A, ꢁ)
D–H. . .A
d(D–H)
d(H. . .A)
d(D. . .A)
\(DHA)
P(3)–H(1). . .Cg
1.42(3)
0.93
0.93
0.93
0.93
2.79(3)
2.58
2.40
2.60
2.80
3.8254(11)
3.436(4)
2.829(5)
2.971(5)
3.475(4)
3.574(4)
127.5(14)
153.9
107.7
104.5
130.5
C(12)–H(12). . .Cl(1)
C(26)–H(26). . .O(3)
C(36)–H(36). . .O(2)
C(46)–H(46). . .Cl(1)
C(66)–H(66). . .Cl(2)
0.93
2.75
147.6
Cg stands for the centroid of the phenyl ring.
˚
[max. deviation of 0.021(1) A], except in the case of the
plane formed by atoms C(1), Cl(1), P(1) and P(3). The
Ru atom lies 0.113(1) A out of the best plane as a conse-
quence of the lack of regularity in the octahedron.
The 31P{1H} NMR spectrum of trans-RuCl2(CO)-
(PHPh2)(POOP) (trans-4) shows three doublets of doublets
1
the proposed formulation [7a,36]. In the H NMR spectra
˚
of 5, two multiplets at 4.06 and 4.28 ppm also appear, due
to the methylene protons of the POOP ligand. The doublet
of multiplets at 5.44 ppm was attributed to the H proton of
the PHPh2 phosphine group. On the basis of these data, a
mer–cis geometry VI may reasonably be proposed for dihy-
dride complex 5.
2
at 15.4, 118.6 and 134.2 ppm, with coupling constants JPP
of 334, 35 and 43 Hz, fitting the mer position of the phos-
phorus ligands. The 1H NMR spectrum displays a doublet
of multiplets at 5.65 ppm, with a coupling constant of
369 Hz attributed to the H atom of the PHPh2 ligand;
the methylene protons of the POOP ligand appear as a
multiplet centred at 4.10 ppm. The IR spectrum shows a
strong band at 1994 cmꢀ1 attributed to mCO and, in the
far region, a medium-intensity band at 320 cmꢀ1, due to
the mRuCl of the two Clꢀ ligands in a mutually trans posi-
tion. On the basis of these data, a mer-trans geometry IV
may be proposed for the trans-4 compound.
The reaction on carbonylated solutions of RuCl3 Æ 3H2O
with bidentate phosphite POOP was also carried out in
Instead, the IR spectra of the related cis isomers cis-4
show two mRuCl bands at 299 and 270 cmꢀ1, fitting the
mutually cis position of the two chloride ligands. The
31P{1H} NMR spectra display three doublets of doublets,
with JPP values of 21, 32 and 375 Hz, in agreement with
the mer arrangement of the three phosphorus nuclei of
the phosphine. On the basis of these data, a mer–cis geom-
etry V, like that observed in the solid state, may be pro-
posed in solution for the cis-4 derivative.
-7.100
-7.300
-7.500
-7.700
-7.900
-8.100
Both cis and trans dichloro-complexes RuCl2(CO)-
(PHPh2)(POOP) (4) react with LiAlH4 in thf to give the
related dihydride complex cis-RuH2(CO)(PHPh2)(POOP)
Fig. 4. 1H NMR spectrum (experimental top, simulated bottom) between
ꢀ7.0 and ꢀ8.2 ppm of compound cis-RuH2(CO)(PHPh2)(POOP) (5).

J. Bravo et al. / Journal of Organometallic Chemistry 692 (2007) 5481–5491
5489
P
CO
Cl
Cl
CO, MeOH
POOP
RuCl3•3H2O
Ru
OC
P
6 ( VII )
P = PPh2OMe
Scheme 6.
methanol instead of thf. In this case, the transesterification
reaction of Ph2POCH2CH2OPPh2 with MeOH, giving
PPh2OMe, is faster than the coordination reaction of
POOP, and yields complex RuCl2(CO)2(PPh2OMe)2 (6)
as final product (Scheme 6).
The carbonylated methanol solution probably contains
chloro-carbonyl ruthenium complexes [RuCl2(CO)2]n or
RuCl2(CO)3(MeOH), which react with the PPh2OMe
forming in solution to give the known dicarbonyl RuCl2-
(CO)2P2 (6) derivative [37]. The use of boiling methanol,
instead of 2-methoxyethanol, as a solvent yielded the all-
trans isomer instead of the cis–cis–trans one [37]. The ther-
modynamically less stable all-trans isomer 6, due to the
mutual competition of both CO ligands for the electronic
charge of the metal [38], can therefore be obtained using
methanol as solvent.
Fig. 5. Molecular structure of compound RuCl2(CO)2(PPh2OMe)2 (6).
The atoms are drawn at 30% probability level.
Table 6
˚
Bond lengths (A) and angles (ꢁ) for 6
Lengths
Ru–C(1i)
Ru–Pi
Ru–Cli
1.943(3)
2.3844(6)
2.4091(6)
Ru–C(1)
Ru–P
Ru–Cl
1.943(3)
2.3844(6)
2.4091(6)
Angles
C(1)–Ru–Pi
C(1)–Ru–P
C(1i)–Ru–C(1)
C(1i)–Ru–Cli
Pi–Ru–Cli
90.74(7)
89.26(7)
180.0
88.87(8)
88.54(2)
91.13(8)
91.46(2)
180.0
C(1i)–Ru–P
Pi–Ru–P
90.74(7)
180.0
Treatment of chloro-complex RuCl2(CO)2(PPh2OMe)2
(6) with NaBH4 in ethanol afforded dihydride derivative
RuH2(CO)2(PPh2OMe)2 (7), which was isolated in moder-
ate yield (Scheme 7).
C(1)i–Ru–Pi
C(1)–Ru–Cli
P–Ru–Cli
89.26(7)
91.13(8)
91.46(2)
88.87(8)
88.54(2)
98.72(11)
C(1i)–Ru–Cl
Pi–Ru–Cl
Cli–Ru–Cl
C(1)–Ru–Cl
P–Ru–Cl
O(2)–P–C(11)
Both chloro-RuCl2(CO)2P2 (6) and hydride RuH2-
(CO)2P2 (7) complexes are stable yellow (6) or orange (7)
solids, soluble in common organic solvents and non-elec-
trolytes. Their formulation is supported by analytical and
spectroscopic data and by X-ray single-crystal structure
determination of RuCl2(CO)2(PPh2OMe)2 (6). The molecu-
lar structure of the complex, including the atom-numbering
scheme, is shown in Fig. 5. Table 6 lists some selected bond
lengths and angles. The compound crystallises in mono-
clinic spatial group C2=c in such a way that the metal atom
is located at the inversion centre of the molecule. The
geometry around the Ru atom is a slightly distorted octa-
hedron with three pairs of symmetry-related ligands in an
all-trans environment. Bond distances Ru–Cl, Ru–C and
Symmetry transformations used to generate equivalent atoms: i 1/2 ꢀ x, 1/
2 ꢀ y, 1 ꢀ z.
plexes like [RuCl2(CO)2(PPh3)2] [39] or [RuCl2(CO)2-
(PBz3)2] [40].
The IR spectrum of chloro-complex RuCl2(CO)2-
(PPh2OMe)2 (6) shows only one mCO band at 2015 cmꢀ1
,
fitting the mutually trans position of the two carbonyl
ligands. In addition, in the far region, only one weak band
at 330 cmꢀ1 is observed, attributable to the mRu–Cl of two
Clꢀ ligands in a mutually trans position. In the temperature
range between +20 and ꢀ80 ꢁC, the 31P NMR spectra
show only one singlet at 120.1 ppm, fitting the presence
˚
Ru–P have values of 2.4091(6), 1.943(3) and 2.3844(6) A,
respectively, at the expected range for bonds between
Ru(II) and the corresponding ligands, and of the same
magnitude as those reported for similar compounds, com-
1
of two magnetically equivalent phosphite ligands. The H
NMR spectra also show the methoxy signals of the
PPh2OMe as a virtual triplet at 3.55 ppm (Jvirtual
=
3JPH + 5JPH = 6.4 Hz), fitting the mutually trans position
of the two phosphite ligands. On the basis of these data,
an all-trans geometry VII, like that found in the solid state,
may be proposed for chloro-complex 6.
P
P
CO
Cl
CO
H
Cl
H
NaBH4
EtOH
Ru
Ru
OC
OC
The IR spectrum of dihydride complex RuH2(CO)2(P-
P
P
Ph2OMe)2 (7) shows one strong absorption at 1972 cmꢀ1
,
6
7 ( VIII )
attributed to the mCO of two carbonyls in a mutually trans
position, and another strong one at 2023 cmꢀ1, due to the
mRu–H of two trans hydride ligands. However, the presence
P = PPh2OMe
Scheme 7.

5490
J. Bravo et al. / Journal of Organometallic Chemistry 692 (2007) 5481–5491
1
of the Hꢀ ligand is confirmed by the H NMR spectra,
which show a sharp singlet at ꢀ7.63 ppm. T1 measurements
on this signal gave a T1(min) value of 467 ms (at 400 MHz),
(b) K. Abdur-Rashid, R. Abbel, A. Hadrovic, A.J. Lough, R.H.
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926;
1
fitting the classical nature of dihydride complex 7. The H
NMR spectra of 7 also show a sharp triplet at 3.53 ppm
(Jvt = 7 Hz), due to the methoxy resonance of the two
PPh2OMe phosphite ligands in a mutually trans position.
In the temperature range between +20 and ꢀ80 ꢁC, the
31P{1H} NMR spectra appear as a sharp singlet, confirm-
ing the magnetic equivalence of the two phosphite ligands.
On the basis of these data, an all-trans geometry VIII, like
that of chloro-precursors 6, may be proposed for dihydride
complex 7.
(c) R.H. Crabtree, Angew. Chem., Int. Ed. Engl. 32 (1993) 789–
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4. Conclusions
(c) G. Albertin, S. Antoniutti, S. Garc´ıa-Fonta´n, R. Carballo, F.
Padoan, J. Chem. Soc., Dalton Trans. (1998) 2071–2081;
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This report describes new routes for preparing dihydride
complexes of ruthenium with bidentate phosphite ligands,
giving rise to unprecedented dihydrides RuH2(PFFP)2,
RuH2(POOP)2 and RuH2(CO)(PHPh2)(POOP). An unex-
pected example of metal-mediated fragmentation of the
bidentate phosphite POOP, yielding the secondary phos-
phine PHPh2, is observed. The spectroscopic data and
structural parameters of both dichloro- and dihydride com-
plexes are also reported.
´
´
(e) S. Bolano, J. Bravo, S. Garcıa-Fontan, J. Castro, J. Organomet.
˜
Chem. 667 (2003) 103–111;
´
´
(f) S. Bolano, J. Bravo, S. Garcıa-Fontan, Eur. J. Inorg. Chem.
˜
(2004) 4812–4819;
´
´
´
(g) S. Bolano, J. Bravo, J. Castro, S. Garcıa-Fontan, M.C. Marın, P.
˜
´
Rodrıguez-Seoane, J. Organomet. Chem. 690 (2005) 4945–4958;
´
(h) G. Albertin, S. Antoniutti, C. Busato, J. Castro, S. Garcıa-
´
Fontan, Dalton Trans. (2005) 2641–2649;
´
´
(i) G. Albertin, S. Antoniutti, J. Bravo, J. Castro, S. Garcıa-Fontan,
´
`
M.C. Marın, M. Noe, Eur. J. Inorg. Chem. (2006) 3451–3462;
5. Supplementary material
´
´
´
´
(j) J. Bravo, J. Castro, S. Garcıa-Fontan, M.C. Rodrıguez-Martınez,
P. Rodr´ıguez-Seoane, Eur. J. Inorg. Chem. (2006) 3028–3040.
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cals, 3rd ed., Butterworthand Heinemann, Oxford, 1988.
CCDC 652770, 639443, 639141 and 639142 contains the
supplementary crystallographic data for this paper. These
data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
´
´
[10] S. Bolano, J. Bravo, S. Garcıa-Fontan, Inorg. Chim. Acta 315 (2001)
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