Coordination chemistry and catalytic activity of ruthenium complexes of terdentate phosphorus-nitrogen-phosphorus (PNP) and bidentate phosphorus-nitrogen (PNH) ligands

Article abstract of DOI:10.1021/om0201314

Structures of trans-dichlororuthenium(II) complexes of aminodiphosphines RN (CH₂CH₂-PPh₂)₂ and aminophosphines RN(H)CH₂CH₂PPhi2₂ ligands were examined. The comparative reactivity

Full text of DOI:10.1021/om0201314

Organometallics 2002, 21, 4927-4933
4927
Coor d in a tion Ch em istr y a n d Ca ta lytic Activity of
Ru th en iu m Com p lexes of Ter d en ta te
P h osp h or u s-Nitr ogen -P h osp h or u s (P NP ) a n d Bid en ta te
P h osp h or u s-Nitr ogen (P NH) Liga n d s
Mohammed S. Rahman, Paul D. Prince, J onathan W. Steed, and
King Kuok (Mimi) Hii*
Department of Chemistry, King’s College London, Strand, London WC2R 2LS, U.K.
Received February 19, 2002
Structures of trans-dichlororuthenium(II) complexes of aminodiphosphines RN(CH2CH2-
PPh2)2 (1a -d , PNP) and aminophosphines RN(H)CH2CH2PPh2 (2a -d , PNH) ligands are
examined. The comparative reactivity of these metal complexes in ruthenium-catalyzed
transfer hydrogenation reactions is subsequently evaluated.
Sch em e 1. Am in od ip h osp h in e (P NP ) a n d
Am in op h osp h in e (P NH) Liga n d s
In earlier papers we described the synthesis of a range
of aminodiphosphine (PNP) ligands 1, their hemilabile
coordination to palladium complexes,1 and their cata-
lytic behavior in the Heck arylation reaction.2 During
the course of this work, we developed a simple two-step
procedure for the synthesis of a series of the ligands 1
(PNP) and 2 (PNH) from readily available amines
(Scheme 1).3
In an earlier study, a cis,fac-[RuCl2(PNP)(PPh3)] com-
plex was reported to be formed by refluxing a mixture
of PhCH2N(CH2CH2PPh2)2 (1d ) and [RuCl2(PPh3)3] in
hexane, and the assignment was made, based chiefly
on infrared and 1H NMR spectroscopic data.4 In con-
trast, Bianchini and co-workers isolated a trans,mer-
[RuCl2(PNP)(PPh3)] complex by refluxing [RuCl2(PPh3)3]
and ligand 1a in THF.5,6 As the two systems differ only
in the substitution at nitrogen, the contrasting results
led us to reexamine the ruthenium complexes of these
amino (di)phosphine ligands. In particular, we wish to
investigate the effect of the nitrogen substitution on the
coordination and catalytic chemistry.
Adopting previously described procedures, the amino
diphosphine ligands (1a -1d ) were refluxed with [RuCl2-
(PPh3)3] in hexane (Scheme 2).4 In all cases, the reaction
mixtures recorded an AX2 spin system (J PP ≈ 27 Hz) in
their 31P{1H} NMR spectra, in addition to two displaced
triphenylphosphine ligands (δP -5 ppm), which is
consistent with Bianchini’s structure in which the PNP
ligand adopts a mer-configuration around the metal
center.
Sch em e 2. Coor d in a tion of P NP Liga n d s to
[Ru Cl2(P P h 3)3]
Single crystals of 4b and 4d suitable for X-ray
diffraction analysis were obtained by slow diffusion of
petroleum ether into solutions of the complexes in
dichloromethane. Both structures showed meridonal
arrangement of the PNP ligands around the octahedral
metal centers, with the chloride ligands occupying the
apical positions (Figure 1), i.e. a trans,mer-configuration.
The preferred geometry affords the least sterically
congested coordination sphere, while also placing ligands
with comparable trans-effects (Cl-, RPPh2) in mutually
trans-configurations.
* Corresponding author. Fax: +44-(0)20-78482810. E-mail:
mimi.hii@kcl.ac.uk.
(1) Hii, K. K.; Thornton-Pett, M.; J utand, A.; Tooze, R. P. Organo-
metallics 1999, 18, 1887-1896.
(2) Qadir, M.; Mo¨chel, T.; Hii, K. K. Tetrahedron 2000, 56, 7975-
7979.
(3) Rahman, M. S.; Steed, J . W.; Hii, K. K. Synthesis 2000, 1320-
1326.
(4) Khan, M. M. T.; Reddy, V. V. S. Inorg. Chem. 1986, 25, 208-
214.
(5) Bianchini, C.; Innocenti, P.; Masi, D.; Peruzzini, M.; Zanobini,
F. Gazz. Chim. Ital. 1992, 122, 461-470.
(6) Bianchini, C.; Masi, D.; Peruzzini, M.; Romerosa, A.; Zanobini,
F. Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 1995, 51, 2514.
The solid-state structures of 4b and 4d reveal notice-
able differences in their coordination spheres induced
by the different nitrogen substituents (Table 1). Al-
10.1021/om0201314 CCC: $22.00 © 2002 American Chemical Society
Publication on Web 10/10/2002

4928 Organometallics, Vol. 21, No. 23, 2002
Rahman et al.
F igu r e 1. ORTEP diagrams of complexes 4b (left) and 4d (right) at 50% probability. Solvent molecules and hydrogen
atoms are omitted for clarity.
Ta ble 1. Selected Bon d Len gth s a n d Bon d An gles
for Com p lexes 4b a n d 4d
Sch em e 3. Coor d in a tion of P NH Liga n d s to
[Ru Cl2(P P h 3)3]
complex 4b
complex 4d
Selected Bond Lengths (Å)
Ru(1)-P(2)
2.309(2)
2.315(5)
2.365(2)
2.371(1)
2.437(2)
2.438(2)
Ru(1)-P(2)
2.319(2)
2.317(7)
2.394(2)
2.382(2)
2.414(2)
2.413(2)
Ru(1)-N(1)
Ru(1)-P(1)
Ru(1)-P(3)
Ru(1)-Cl(2)
Ru(1)-Cl(1)
Ru(1)-N(1)
Ru(1)-P(1)
Ru(1)-P(3)
Ru(1)-Cl(1)
Ru(1)-Cl(2)
Selected Bond Angles (deg)
176.74(11) N(1)-Ru(1)-P(2)
N(1)-Ru(1)-P(2)
N(1)-Ru(1)-P(1)
N(1)-Ru(1)-P(3)
P(2)-Ru(1)-P(1)
P(2)-Ru(1)-P(3)
P(1)-Ru(1)-P(3)
177.40(18)
80.48(18)
81.93(18)
97.24(8)
100.20(9)
161.47(9)
Sch em e 4. Ru th en iu m -Ca ta lyzed Tr a n sfer
Hyd r ogen a tion of Keton es to Alcoh ols
79.18(11)
81.22(11)
97.85(5)
101.33(5)
156.18(6)
N(1)-Ru(1)-P(1)
N(1)-Ru(1)-P(3)
P(2)-Ru(1)-P(1)
P(2)-Ru(1)-P(3)
P(1)-Ru(1)-P(3)
N(1)-Ru(1)-Cl(1) 91.43 (12) N(1)-Ru(1)-Cl(1) 91.30(18)
N(1)-Ru(1)-Cl(2) 89.75 (12) N(1)-Ru(1)-Cl(2) 83.56 (18)
Cl(2)-Ru(1)-Cl(1) 177.07(5)
Cl(2)-Ru(1)-Cl(1) 174.41(9)
though the Ru-N bonds appear to be unaffected,
complex 4d displays very slight increase and decrease
in the Ru-P and Ru-Cl bond lengths compared to 4b,
as will be expected to result from reduced electron
donation by the amino group. More significantly, the
Cl-Ru-Cl angle in complex 4d deviates significantly
from linearity, due entirely to the distortion of one of
the chloride ligands, manifested by the observed N(1)-
Ru(1)-Cl(2) bond angle of 83.5° compared to N(1)-Ru-
(1)-Cl(1) of 91.3 °C. Such a difference is not observed
in complex 4b, where these bond angles are virtually
orthogonal: N(1)-Ru(1)-Cl(2) ) 89.7°; N(1)-Ru(1)-Cl-
(1) ) 91.4 °C. We propose that this difference of the two
Ru-Cl bonds in complex 4d effectively destroys the
molecular symmetry, leading to the observation of two
ν(Ru-Cl) IR absorption bands and, consequently, an
erroneous assignment of a cis,fac-structure in the previ-
ous report.4 Indeed, subsequent examination of far-
infrared absorption of the isolated ruthenium complexes
4a -4d showed complex 4d to be the only compound of
this series that exhibits two bands in this region.
Ru th en iu m (II) Com p lexes of Am in op h osp h in e
Liga n d s 2. Two molar equivalents of the bidentate
PNH ligands 2 displaced triphenylphosphine from [RuCl2-
(PPh3)3] in refluxing 2-propanol, to furnish orange solids
with the molecular composition [Ru(PNH)2Cl2]. The
isolated complexes gave rise to singlet resonances at ca.
60 ppm in their 31P{1H} NMR spectra, consistent with
the formation of symmetrical bis-ligated structures
(Scheme 3). The molecular structures were determined
by the isolation of suitable crystals of complexes 5a and
5d for X-ray crystallography by recrystallization from
dichloromethane/hexane (two molecules of complex 5a
were found in the asymmetric part of the unit cell).
The structures have distorted octahedral geometries
around the metal centers with a cis,trans-configuration,
i.e., with the two phosphorus and nitrogen atoms cis to
each other and the mutually trans-dichloride ligands
adopting the apical positions (Figure 2). A striking
feature is the highly distorted Cl-Ru-Cl bonds (ca.
167°). As no other [(PNH)2RuCl2] complexes were
reported prior to this work, the data were compared to
similar crystal structures retrieved from the Cambridge
Crystallographic Database using QUEST and VISTA.7
Searches were restricted to complexes of cis,trans-
(7) Cambridge Structural Database System, October 2001 Release:
Allen, F. H.; Kennard, O. Chem. Des. Autom. News 1993, 8, 1 and 31.

Ru Complexes of PNP and PNH Ligands
Organometallics, Vol. 21, No. 23, 2002 4929
F igu r e 2. ORTEP representations of 5a (left) and 5d (right) at 50% probability. Solvent molecules and hydrogen atoms
are omitted for clarity.
F igu r e 3. Types of cis,trans-[RuP2N2Cl2] complexes previously reported. Trans-chloride ligands are omitted for the sake
of clarity.
[RuCl2P2N2] complexes containing two nitrogen and two
phosphorus donor groups (chelation between donor
groups is optional and could be in any combination),
with R factor < 10%. Surprisingly, few crystal struc-
tures of this type were reported: only a total of 15 data
sets representing seven distinct compounds were found
(Figure 3).
Even within this relatively modest data set, it is clear
that distortions are not uncommon in these complexes
(Table 2), with the Cl-Ru-Cl bond angles ranging
between 163° and 173°. Examination of the interatomic
distances shows that the nitrogen substituent affects
the structure of these compounds in an entirely different
way from that observed previously with the PNP
complexes: Ru-Cl and Ru-P bond lengths are fairly
insensitive to the nature of the nitrogen donor. However,
the Ru-N bonds are shorter by about 0.2 Å in complexes
5a and 5d (containing a NH moiety), compared to those
containing tertiary amino groups (HIWGOJ , NODRAZ,
and SUSQUS, Table 2). Perhaps as a result of closer
atomic contacts in the equatorial plane, greater repul-
sion is experienced between the chloride ligands and the
aromatic rings, resulting in the greater displacement
of the dichloride ligands toward the nitrogen donors.
Indeed, the Cl-Ru-Cl distortion appears to increase
in the following order: tertiary amine < imine <
secondary NH.
Another interesting feature is the chemical environ-
ment of the Ru-Cl bonds, reflected through the differ-
ence in Cl-Ru-N torsion angles. The Ru-Cl bonds in
complexes 5a and 5d appear to be distinctly different,
N(2)-Ru(1)-Cl deviating from N(1)-Ru(1)-Cl by as
much as >8° (Table 2). This contrasts sharply with the
other structures that show deviations of less than 2.6°
between the two values. These differences again destroy
the C2 symmetrical structure and are manifested in the
appearance of two ν(Ru-Cl) far-infrared absorption
bands for complexes 5a -5d .
Ru th en iu m -Ca ta lyzed Tr a n sfer Hyd r ogen a tion
Rea ction s. Catalytic transfer hydrogenation reaction
is an attractive reaction protocol for the reduction of
ketones to alcohols.8,9 By using 2-propanol as the
(8) Zassinovich, G.; Mestroni, G.; Gladiali, S. Chem. Rev. 1992, 92,
1051-1069.
(9) Noyori, R.; Ohkuma, T. Angew. Chem., Int. Ed. 2001, 40, 40-
73.

4930 Organometallics, Vol. 21, No. 23, 2002
Ta ble 2. Selected Bon d An gles (d eg) a n d Bon d Len gth s of [P 2N2Ru Cl2] Com p lexes
Rahman et al.
REFCODE
ClRuCl Cl1RuN1 Cl2RuN1 Cl2RuN2 Cl1RuN2 |∆(ClRuN1)| |∆(ClRuN2)|
M-Cl
M-P
M-N
NUTDEL17a
162.939 82.497
162.958 82.951
83.051
83.245
83.123
83.418
79.037
88.536
87.47
84.287
93.654
81.796
85.69
84.301
83.518
83.536
82.418
88.807
78.777
82.769
89.259
98.303
88.344
80.99
83.884
83.806
82.821
84.266
81.513
87.285
87.627
84.501
93.349
79.454
91.91
0.554
0.294
1.113
0.43
7.912
6.749
7.395
2.688
4.03
0.417
0.288
0.715
1.848
7.294
8.508
4.858
4.758
4.954
8.89
2.42, 2.42
2.426, 2.409 2.28, 2.27
2.408, 2.425 2.276, 2.295 2.142, 2.189
2.412, 2.416 2.301, 2.275 2.187, 2.14
2.41, 2.432
2.409, 2.43
2.444, 2.409 2.303, 2.304 2.167, 2.163
2.418, 2.427 2.292, 2.297 2.094, 2.097
2.365, 2.365 2.42, 2.398
2.282, 2.274 2.196, 2.185
2.183, 2.188
NUTDIP17a,b 163.002 84.236
163.21
83.848
ZUXCIE0118c 164.125 86.949
2.3, 2.289
2.297, 2.29
2.158, 2.163
2.14, 2.164
ZUXCIE12c
ZUDKOY19d
LAPRAV20d
NOLNUX21
WOQHUF22
5a a
164.213 81.787
165.33 80.075
169.976 86.975
165.676 97.684
2.025, 2.033
165.34
166.82
166.10
166.76
88.077
83.46
82.51
81.68
6.281
2.23
3.41
2.418, 2.4 2.273, 2.269 2.228, 2.263
10.92
8.6
9.08
2.402, 2.419 2.249, 2.251 2.242, 2.249
2.408, 2.417 2.248, 2.252 2.233, 2.253
2.407, 2.412 2.251, 2.253 2.242, 2.246
2.439, 2.403 2.295, 2.288 2.099, 2.091
2.415, 2.405 2.301, 2.311 2.375. 2.332
2.41, 2.395
2.41, 2.412
2.402, 2.418 2.255, 2.241 2.404, 2.368
85.92
87.16
82.12
82.05
90.72
91.13
5d
5.48
ZUXCEA12e
HIWGOJ 23
NODRAZ24f
171.654 89.459
172.713 87.143
172.139 84.396
88.961
173.159 86.255
84.767
87.015
90.41
85.463
89.611
89.235
86.251
83.759
88.238
86.518
83.899
88.457
90.872
86.319
88.327
4.692
0.128
6.014
3.498
3.356
5.336
2.206
7.113
1.919
1.809
2.255, 2.251 2.402, 2.377
2.257, 2251 2.414, 2.377
SUSQUS25a,f 171.87
a
b
Two molecules found in the asymmetric unit cell. Stereoisomer of NUTDEL. c,d,f Identical structures, reported independently/in
different solvents. e Stereoisomer of ZUXCIE.
Ta ble 3. Ca ta lytic Activity of Com p lexes 4a -5d a
complexes 4 (entries 2-5 and 10). As expected, the
presence of the NH functionality makes a dramatic
difference to the turnovers of the reactions (entries 2-5
vs 6-10). This fits in well with the well-established
observation that an NH group is essential in the rate-
determining hydride transfer step.11 We found that a
reaction temperature of at least 60 °C is required in
order for complexes 5a -5d to achieve any observable
turnover. This, compared to the lower reaction temper-
ature required for complexes ZUXICE (ca. 30-40 °C),
suggests that the N-N tether imbues special reactivity
to the PNNP system.
Within each ligand class, the reactivity of the metal
complexes is dependent on the nitrogen substituents.
For the PNP complexes 4a -4d , the higher homologues
induced lower reaction turnover and yield (entries 2, 3,
and 4), with the 4d displaying the lowest activity. In
contrast, the PNH complexes 5a -5d seem to display
the opposite trend: the butyl-substituted 5c had higher
activity than the propyl homologue 5a (entries 6 and
8). Increasing the steric bulk of the N-substituent
decreased the reactivity (entry 7), and the benzyl-
substituted 5d was the least reactive (entry 9).
entry
catalyst
% conversion (h) final % conversion (h)
1
2
3
4
5
6
7
8
9
RuCl2(PPh3)3
41 (4)
22 (8)
15 (8)
17 (8)
13 (8)
67 (4)
59 (4)
88 (4)
39 (4)
49 (8)
85 (72)
81 (72)
68 (72)
55 (72)
87 (8)
76 (8)
94 (8)
55 (8)
4a
4b
4c
4d
5a
5b
5c
5d
a
Reactions were carried out in duplicate, using a Radley’s
reaction carousel system under a nitrogen atmosphere, using 1
mol % of catalyst at 83 °C. % conversions monitored by GC.
reductant, H- and H+ are delivered simultaneously to
the carbonyl functionality, thus avoiding the use of
stoichiometric, hazardous reducing reagents such as
NaBH4 and LiAlH4. Impressive stereoselectivity could
also be achieved by the use of chiral ligands in recent
years. The most efficient catalysts reported for the
reaction contain bifunctional ligands, e.g., â-amino
alcohols, N-tosylated diamines, oxazoline-phosphines.10,11
Among the nitrogen-phosphorus ligands, the tethered
aminophosphine PNNP complexes such as ZUXCIE
(Figure 3) is able to catalyze the reaction of aryl alkyl
ketones at mild reaction temperatures while delivering
high ee’s.12-14 As these complexes are not too dissimilar
to complexes 5a -5d , we decided to investigate the
comparative reactivity of these complexes. Using the
isolated complexes 4a -4d and 5a -5d as catalytic
precursors, acetophenone was subjected to transfer hy-
drogenation reactions in a refluxing 2-propanol solution
(Scheme 3). The results are summarized in Table 3.
The PNH complexes 5 generally catalyze reactions
faster than [RuCl2(PPh3)3] (Table 3, entries 1 and 6-9),
which is in turn a better catalyst than the PNP
Con clu sion
Amino phosphines and diphosphine ligands 1 and 2
have been prepared and their coordination chemistry
on dichlororuthenium(II) complexes was evaluated.
Complexes of the PNP terdentate ligand (4a -4d ) were
found to have a trans,mer arrangement around the
metal center, whereas the bidentate PN(H) ligands form
cis,trans complexes (5a -5d ) in a highly sterically
strained octahedral arrangement. The effect of nitrogen
substituent on the overall geometry of these metal
complexes was discussed. In catalytic transfer hydro-
genation reactions the reactivity was found to be PNH
(5c > 5a > 5b > 5d ) > PNP (4a > 4b > 4c > 4d ).
Chiral variants of the PNP and PNH ligands are
being developed in our laboratory and evaluated in
asymmetric catalytic reactions. The results will be
reported elsewhere.
(10) Palmer, M. J .; Wills, M. Tetrahedron-Asymmetry 1999, 10,
2045-2061.
(11) Yamakawa, M.; Ito, H.; Noyori, R. J . Am. Chem. Soc. 2000, 122,
1466-1478.
(12) Gao, J . X.; Ikariya, T.; Noyori, R. Organometallics 1996, 15,
1087-1089.
(13) Gao, J . X.; Xu, P. P.; Yi, X. D.; Yang, C. B.; Zhang, H.; Cheng,
S. H.; Wan, H. L.; Tsai, K. R.; Ikariya, T. J . Mol. Catal. A 1999, 147,
105-111.
Exp er im en ta l Section
All reactions involving phosphorus(III) ligands were carried
out under inert atmospheres of nitrogen or argon using
(14) Gao, J . X.; Zhang, H.; Yi, X. D.; Xu, P. P.; Tang, C. L.; Wan, H.
L.; Tsai, K. R.; Ikariya, T. Chirality 2000, 12, 383-388.

Ru Complexes of PNP and PNH Ligands
Organometallics, Vol. 21, No. 23, 2002 4931
complex 4d ‚2CH2Cl2
Ta ble 4. Cr ysta l Da ta a n d Str u ctu r e Refin em en t for Com p lexes 4b a n d 4d
complex 4b
empirical formula
fw
temperature
wavelength
cryst syst
space group
unit cell dimens
C
50H52Cl2NP3Ru
empirical formula
C53H50Cl2NP3Ru‚2CH2Cl2
1135.67
931.81
fw
100(2) K
0.71073 Å
P1h
triclinic
temperature
wavelength
cryst syst
space group
unit cell dimens
100(2) K
0.71073 Å
P21/c
monoclinic
a ) 10.5452(3) Å, R ) 87.473(2)°
b ) 18.7436(6) Å, â ) 76.456(2)°
c ) 22.5033(7) Å, γ ) 89.987(2)°
4319.8(2) Å3
a ) 14.1873(10) Å, R ) 90°
b ) 14.5637(6) Å, â ) 106.374(4)°
c ) 25.5349(15) Å, γ ) 90°
5062.0(5) Å3
volume
Z
density (calcd)
abs coeff
F(000)
cryst size
θ range for data collection
index ranges
volume
Z
density (calcd)
abs coeff
F(000)
cryst size
θ range for data collection
index ranges
4
4
1.433 Mg/m3
1.490 Mg/m3
0.635 mm-1
0.760 mm-1
1928
2328
0.20 × 0.10 × 0.02 mm3
0.20 × 0.15 × 0.10 mm3
1.40 to 25.00°
2.36 to 25.00°
-12 e h e 12, -22 e k e 22,
-26 e l e 26
-16 e h e 16,-16 e k e 17,
-30 e l e 30
no. of reflns collected
no. od ind reflns
25 256
no. of reflns collected
no. of ind reflns
15 463
15193 [R(int) ) 0.1063]
8721 [R(int) ) 0.1302]
completeness to θ ) 25.00°
max. and min. transmn
refinement method
no. of data/restraints/
params
99.8%
completeness to θ ) 25.00°
max. and min. transmn
refinement method
no. of data/restraints/
params
98.0%
0.9874 and 0.8836
full-matrix least-squares on F2
15193/0/1030
0.9278 and 0.8628
full-matrix least-squares on F2
8721/0/596
goodness-of-fit on F2
final R indices [I>2σ(I)]
R indices (all data)
extinction coeff
1.043
goodness-of-fit on F2
final R indices [I>2σ(I)]
R indices (all data)
extinction coeff
1.037
R1 ) 0.0665, wR2 ) 0.1000
R1 ) 0.1273, wR2 ) 0.1156
0.00098(14)
R1 ) 0.0911, wR2 ) 0.2012
R1 ) 0.1529, wR2 ) 0.2442
0.0036(5)
largest diff peak and hole
0.666 and -0.671 e Å-3
largest diff peak and hole
1.532 and -1.164 e Å-3
Ta ble 5. Cr ysta l d a ta a n d Str u ctu r e Refin em en t for com p lexes 5a a n d 5d
complex 5a complex 5d
empirical formula
fw
temperature
wavelength
cryst syst
space group
unit cell dimens
C
34H42Cl2N2P2Ru
empirical formula
fw
temperature
wavelength
cryst syst
space group
unit cell dimens
C42H44Cl2N2P2Ru
712.61
810.70
100(2) K
0.71073 Å
P1h
triclinic
293(2) K
0.71073 Å
P1h
triclinic
a ) 11.5098(6) Å, R) 82.246(3)°
b ) 15.8943(8) Å, â) 72.680(3)°
c ) 19.2179(8) Å, γ ) 77.757(2)°
3270.3(3) Å3
a ) 10.9686(6) Å, R) 97.173(4)°
b ) 12.1947(8) Å, â) 107.402(4)°
c ) 16.7431(11) Å, γ ) 110.999(4)°
1926.2(2) Å3
volume
Z
density (calcd)
abs coeff
F(000)
cryst size
θ range for data collection
index ranges
volume
Z
density (calcd)
abs coeff
F(000)
cryst size
θ range for data collection
index ranges
4
2
1.447 Mg/m3
1.398 Mg/m3
0.767 mm-1
0.661 mm-1
1472
836
0.20 × 0.10 × 0.10 mm3
0.10 × 0.10 × 0.05 mm3
1.11 to 26.00°
2.70 to 25.00°
-14 e h e 13, -19 e k e 19,
-23 e l e 21
-12 e h e 13, -14 e k e 13,
-19 e l e 19
no. of reflns collected
no. of ind reflns
20 328
no. of reflns collected
no. of ind reflns
11 260
12739 [R(int) ) 0.0843]
6748 [R(int) ) 0.1110]
completeness to θ ) 25.00°
max. and min. transmn
refinement method
no. of data/restraints/
params
99.0%
completeness to θ ) 25.00°
max. and min. transmn
refinement method
99.6%
1.0000 and 0.8617
full-matrix least-squares on F2
12739/0/743
0.9677 and 0.9369
full-matrix least-squares on F2
6748/0/447
no. of data/restraints/params
goodness-of-fit on F2
final R indices [I>2σ(I)]
R indices (all data)
largest diff peak and hole
1.054
goodness-of-fit on F2
final R indices [I>2σ(I)]
R indices (all data)
1.078
R1 ) 0.0672, wR2 ) 0.1108
R1 ) 0.1211, wR2 ) 0.1271
1.343 and -1.152 e Å-3
R1 ) 0.0765, wR2 ) 0.1062
R1 ) 0.1333, wR2 ) 0.1210
0.817 and -0.510 e Å-3
largest diff peak and hole
standard Schlenk line techniques. Commercially available
reagents were purchased from Avocado, Lancaster, or Aldrich
chemical companies and used as received. Diphenylvinylphos-
phine oxide and [RuCl2(PPh3)3] were prepared according to
published procedures.15,16 The preparation of ligands 1a -1d
and 2a -2d was reported previously.3
Melting points were determined on Electrothermal Gallen-
hamp melting point apparatus and are uncorrected. Far-
infrared spectra were recorded on a Perkin-Elmer Paragon
1000 FTIR spectrometer, and samples were suspended in Nujol
sandwiched between polyethylene disks. NMR spectra were
recorded using Bruker AM360 or AVANCE 400 or 500
spectrometers in deuteriochloroform, unless otherwise stated.
1H and 13C spectra were referenced to TMS, and 31P NMR
(15) Collins, D. J .; Rowley, L. E.; Swan, J . M. Aust. J . Chem. 1974,
27, 841-851.
(16) Hallman, P. S.; Stephenson, T. A.; Wilkinson, G. Inorg. Synth.
1970, 12, 237.
(17) Doucet, H.; Ohkuma, T.; Murata, K.; Yokozawa, T.; Kozawa,
M.; Katayama, E.; England, A. F.; Ikariya, T.; Noyori, R. Angew. Chem.,
Int. Ed. 1998, 37, 1703-1707.
(18) Wong, W. K.; Chik, T. W.; Feng, X.; Mak, T. C. W. Polyhedron
1996, 15, 3905-3907.
(19) Gao, J . X.; Wan, H. L.; Wong, W. K.; Tse, M. C.; Wong, W. T.
Polyhedron 1996, 15, 1241-1251.
(20) Wong, W. K.; Gao, J . X.; Zhou, Z. Y.; Mak, T. C. W. Polyhedron
1993, 12, 1415-1417.
(21) Danopoulos, A. A.; HayMotherwell, R. S.; Wilkinson, G.; Caf-
ferkey, S. M.; Sweet, T. K. N.; Hursthouse, M. B. J . Chem. Soc., Dalton
Trans. 1997, 3177-3184.

4932 Organometallics, Vol. 21, No. 23, 2002
Rahman et al.
spectra were referenced to H3PO4 (δ ) 0 ppm). The chemical
shifts (δ) are in parts per million (ppm). The coupling constants
(J ) are in hertz (Hz). The following abbreviations are used: s
(singlet), t (triplet), q (quartet), m (multiplet), d (doublet), br
(broad). Mass spectra (MS and HRMS) were recorded using
FAB technique by the Mass Spectrometry Service within The
University of London’s Intercollegiate Research Services (UL-
IRS) or The EPSRC Mass Spectrometry Service at Swansea,
Wales. Elemental analysis was carried out at The University
of North London.
Catalytic reactions were carried out using a Radley’s 12-
placed reaction carousel under reflux and an inert atmosphere.
A Unicam 6100 system with a J W Scientific DB 250 column
and FID detector was used for GLC analysis.
X-r a y Cr ysta l Str u ctu r a l An a lysis. Crystals of 4b, 4d ,
5a , and 5d were obtained by recrystallization from CH2Cl2/
hexane at room temperature. Data were collected in wide-
slicing mode using a Nonius Kappa CCD diffractometer, with
a detector to crystal distance of 30 mm. Crystal data and
details of data collection and refinement are given as Sup-
porting Information.
(d, J PP ) 27 Hz), 48.10 (t, J PP ) 27 Hz). 13C NMR (100.6 MHz,
CD2Cl2): δ 13.2 (s, CH3CH2), 20.1 (s, CH3CH2), 21.7 (s, CH3-
CH2CH2), 35.2 (virtual triplet, J PC ) 12.0 Hz, NCH2CH2P),
56.6 (s, NCH2CH2P), 60.1 (s, CH3CH2CH2CH2N) 121.3-141.0
(aromatic). HRMS: exact mass calcd for C50H52Cl2NP3Ru
931.1733, found 931.1749. Far-IR ν(Ru-Cl): 310 cm-1. Anal.
Found: C, 62.65; H, 5.01; N, 1.32. C50H52Cl2NP3Ru.CH2-
Cl2‚0.5CH2Cl2 requires: C, 62.25; H, 5.48; N, 1.44.
1
Dich lor o(t r ip h en ylp h osp h in e){b is(2-(d ip h en ylp h os-
ph in o)eth yl)-n -h eptylam in e}r u th en iu m (II), 4c. Yield: 85%.
1H NMR (400 MHz, toluene-d8): δ 0.93 (t, 3H, J ) 8.0 Hz,
CH3CH2), 1.06-1.62 (m, 10H CH3CH2CH2CH2CH2CH2), 2.49-
2.55 (m, 2H, NCH2CH2P), 2.58-2.77 (m, 2H, NCH2CH2P),
3.04-3.08 (m, 2H, NCH2CH2P), 3.46-3.52 (m, 2H, NCH2-
CH2P), 3.79-3.84 (m, 2H C6H13CH2N), 6.75-8.45 (m, 35H, Ph).
31P NMR (161.9 MHz, toluene-d8): δ 26.1 (d, J PP ) 27.5 Hz),
49.4 (t, J PC) 27.5 Hz). 13C NMR (90.5 MHz, toluene-d8): δ 14.7,
1
20.5, 23.5, 27.9, 29.7, 32.6, 36.6, (virtual triplet, J PC ) 11.8
Hz, CH2P) 53.6, (s, NCH2CH2P), 59.1 (s, C6H13CH2N) (aromatic
region). HRMS: exact mass calcd for C53H58Cl2NP3Ru 973.2203,
found 973.2245. Far-IR ν(Ru-Cl): 310 cm-1. Anal. Found: C,
61.63; H, 5.90; N, 1.38. C53H58Cl2NP3Ru.CH2Cl2 requires: C,
61.25; H, 5.71; N, 1.32.
Gen er a l P r oced u r e for th e P r ep a r a tion of [Ru Cl2(P NP )-
(P P h 3)] Com p lexes. Dich lor o(tr ip h en ylp h osp h in e){bis-
(2-(d ip h en ylp h osp h in o)eth yl)ben zyla m in e}r u th en iu m -
(II), 4d . The ligand bis[2-(diphenylphosphino)ethyl]benzyla-
mine (0.11 g, 2 mmol) was added to a solution of [RuCl2(PPh3)3]
(96 mg, 1 mmol) in hexane (10 mL), and the reaction mixture
was refluxed for 4 h. Upon cooling to room temperature, the
product deposited as an orange solid, which was collected by
filtration and washed with acetone/ether. Yield: 72 mg, 75%.
1H NMR (360 MHz, CDCl3): δ 2.69-2.86 (m, 4H, CH2P), 3.10-
3.35 (dm, 4H, NCH2CH2P), 4.77 (s, 2H, C6H5CH2N), 6.68-8.16
Gen er a l P r oced u r e for th e P r ep a r a tion of [Ru Cl2-
(P N)2] Com p lexes: Bis[n -p r op yl{2-(d ip h en ylp h osp h in o)-
et h yl}a m in e]r u t h en iu m (II) Dich lor id e, 5a . [2-(Diphe-
nylphosphino)ethyl]-n-propylamine‚HCl salt (2 mmol) was
neutralized (pH ) 10) with aqueous NaOH (2M) in 2-propanol,
extracted with DCM, dried (MgSO4), and evaporated. The
resultant oil was then dissolved in 2-propanol (2 mL) and
added to a solution of [RuCl2(PPh3)3] (96 mg, 1 mmol) in
2-propanol (10 mL). The reaction mixture was then refluxed
for 4 h, cooled to room temperature, and reduced to 5 mL,
whereupon the product precipitated as an orange solid, which
was collected by filtration and washed with ether. Yield: 78%.
A sample for microanalysis was recrystallized from CH2Cl2/
CH3OH. As before, the crystals tend to incorporate the CH2-
Cl2 solvent. 1H NMR (400 MHz, CD2Cl2): δ 0.89 (t, 6H, J )
7.4 Hz, CH3CH2), 1.47-1.57 (m, 2H, CH3CH2), 1.84-1.87 (m,
2H, CH3CH2), 2.52-2.68 (m, 2H, NCH2CH2P), 2.70-2.94 (m,
6H, NCH2CH2,P and CH3CH2CH2N), 2.94-3.01 (m, 2H, CH3-
CH2CH2N), 3.42-3.47 (m, 2H, NCH2CH2P), 3.69 (br s, 2H,
NH), 6.91-7.19 (m, 20H, PPh2). 31P NMR (145 MHz, CD2Cl2):
δ 59.2. 13C NMR (100.6 MHz, CD2Cl2): δ 10.5 (s, CH3CH2),
(m, 40H, Ph). 31P NMR (145 MHz, CD2Cl2): δ 24.8 (d, J PP
)
28 Hz), 47.0 (t, J PP ) 28 Hz). 13C NMR (100.6 MHz, CD2Cl2):
1
δ 36.3 (virtual triplet, J PC ) 11.5 Hz, NCH2CH2P), 52.9 (s,
NCH2CH2P), 59.2 (s, C6H5CH2N), 126.7-141.90 (aromatic
region). HRMS: exact mass calcd for C53H50Cl2NP3Ru 973.2203,
found 973.2245. Far-IR ν(Ru-Cl): 312, 270 cm-1
.
Dich lor o(t r ip h en ylp h osp h in e){b is(2-(d ip h en ylp h os-
p h in o)eth yl)-n -p r op yla m in e}r u th en iu m (II), 4a . A mi-
croanalytical sample was prepared by recrystallization from
CH2Cl2/CH3OH. The crystals contain CH2Cl2 solvent mol-
ecules, as verified by NMR and X-ray crystal analysis. Yield:
1
85%. H NMR (400 MHz, CD2Cl2): δ 0.72 (t, 3H, J ) 7.2 Hz,
1
21.6 (s, CH3CH2) 30.5 (virtual triplet, J PC ) 14.4 Hz,
CH3CH2), 1.44 (m, 2H, CH3CH2), 2.43 (m, 2H, CH2P), 2.73-
2.77 (m, 2H, NCH2CH2P), 2.95-299 (m, 2H, NCH2CH2P),
3.38-3.49 (4H, m, NCH2CH2P and CH3CH2CH2N), 6.64-8.01
NCH2CH2P), 46.9 (s, NCH2CH2P), 53.2 (s, CH3CH2CH2N),
126.3-136.0 (aromatic region). HRMS: exact mass calcd for
C
34H44Cl2N2P2Ru 713.1322, found 713.1317. Far-IR ν(Ru-
(m, 35H, Ph). 31P NMR (145.7 MHz, CD2Cl2): δ 26.0 (d, J PP
)
Cl): 312, 280 cm-1. Anal. Found: C, 52.93; H, 5.91; N, 3.35.
27.5 Hz), 48.0 (t, J PP ) 27.5 Hz, NCH2CH2P). 13C NMR (90.5
MHz, CD2Cl2): δ 12.3 (s, CH3CH2), 14.1 (s, CH3CH2), 36.5
C
34H44Cl2N2P2Ru‚CH2Cl2 requires: C, 52.57; H, 5.80; N, 3.50.
Bis[isop r op yl-{2-(d ip h en ylp h osp h in o)et h yl}a m in e]-
1
(virtual triplet t, J PC ) 11.7 Hz, NCH2CH2P), 54.0 (s, NCH2-
r u th en iu m (II) Dich lor id e, 5b. Yield: 84%. 1H NMR (400
MHz, CD2Cl2): δ 1.32 (d, 6H, J ) 6.3 Hz, CH3), 1.44 (d, 6H, J
) 6.3 Hz, CH3), 2.79 (br. d, 4H, NCH2CH2P), 3.04 (br s, 2H,
NCH2CH2P), 3.36 (br s, 2H, NCH2CH2P), 3.64-3.67 (m, 1H,
CH), 4.19 (br s, 2H, NH), 7.00-7.31 (m, 20H, PPh2). 31P NMR
(145 MHz, CD2Cl2): δ 64.4. 13C NMR (100.6 MHz, CD2Cl2): δ
CH2P), 59.7 (s, CH3CH2CH2N), 127.18-140.0 (aromatic re-
gion). HRMS: exact mass calcd for C49H50Cl2NP3Ru 917.1577,
found 917.1615. Far-IR ν(Ru-Cl): 310 cm-1. Anal. Found: C,
59.90; H, 5.52; N, 1.26. C49H50Cl2NP3Ru‚CH2Cl2 requires: C,
59.90; H, 5.23; N, 1.40.
Dich lor o(t r ip h en ylp h osp h in e){b is(2-(d ip h en ylp h os-
ph in o)eth yl)-n -bu tylam in e}r u th en iu m (II), 4b. Yield: 75%.
1H NMR (400 MHz, CD2Cl2): δ 0.71 (t, 3H, J ) 7.0 Hz, CH3-
CH2), 1.14 (m, 2H, CH3CH2CH2), 1.38 (m, 2H, CH3CH2CH2),
2.43 (m, 2H, NCH2CH2P), 2.77 (m, 2H, NCH2CH2P), 2.98 (m,
2H, NCH2CH2P), 3.39 (dm, 4H, NCH2CH2P, CH3CH2CH2CH2N),
6.60-8.00 (m, 35H, Ph). 31P NMR (145 MHz, CDCl3): δ 26.09
1
19.4 (s, CH3), 23.7 (s, CH3), 32.7 (virtual triplet, J PC ) 12.0
Hz, CH2P), 40.2 (s, CH2CH2P), 50.9 (s, CH), 126.5-138.79
(aromatic region). HRMS: exact mass calcd for C34H44Cl2N2P2-
Ru 713.1322, found 713.1317. Far-IR ν(Ru-Cl): 305, 270 cm-1
.
Anal. Found: C, 54.87; H, 5.81; N, 3.55. C34H44Cl2N2P2Ru‚
0.5CH2Cl2 requires: C, 54.73; H, 5.99; N, 3.70.
B is [n -b u t y l{2-(d ip h e n y lp h o s p h in o )e t h y l}a m in e ]-
r u th en iu m (II) Dich lor id e, 5c. Yield: 88%. 1H NMR (400
MHz, CD2Cl2): δ 0.87 (t, 6H, J ) 7.4 Hz, CH3CH2), 1.21-1.39
(m, 4H, CH3CH2), 1.42-1.53 (m, 2H, CH3CH2CH2), 1.79-1.90
(m, 2H, CH3CH2CH2), 2.46-2.59 (m, 2H, NCH2CH2P), 2.69-
2.79 (m, 6H, CH2P and CH3CH2CH2CH2N), 2.91-2.98 (m, 2H,
CH3CH2CH2CH2N), 3.33-3.42 (m, 2H, NCH2CH2P), 3.64 (br.
s, 2H, NH), 6.90-7.63 (m, 20H, PPh2). 31P NMR (161.9 MHz,
(22) Mikami, K.; Korenaga, T.; Ohkuma, T.; Noyori, R. Angew.
Chem., Int. Ed. 2000, 39, 3707-3710.
(23) Song, J . H.; Cho, D. J .; J eon, S. J .; Kim, Y. H.; Kim, T. J .; J eong,
J . H. Inorg. Chem. 1999, 38, 893-896.
(24) Shen, J .-Y.; Slugovc, C.; Wiede, P.; Mereiter, K.; Schmid, R.;
Kirchner, K. Inorg. Chim. Acta 1998, 268, 69-76.
(25) Guo, Z. J .; Habtemariam, A.; Sadler, P. J .; J ames, B. R. Inorg.
Chim. Acta 1998, 273, 1-7.

Ru Complexes of PNP and PNH Ligands
Organometallics, Vol. 21, No. 23, 2002 4933
CD2Cl2): δ 59.4. 13C NMR (100.6 MHz, CD2Cl2): δ 14.2 (s, CH3-
CH2), 20.9 (s, CH3CH2), 31.5 (virtual triplet, J PC ) 12.9 Hz,
NCH2CH2P), 48.2 (s, NCH2CH2P), 52.3 (s, CH3CH2CH2CH2N),
127.3-137.8 (aromatic region). HRMS: exact mass calcd for
Radley’s carousel and were evacuated with vacuum and purged
with argon before the addition of anhydrous 2-propanol (8 mL).
At the appropriate temperature, acetophenone (10 mmol, 1.17
mL) was added, and the reaction was initiated by the addition
of KOH (2.9 mL, 0.05M solution in 2-propanol, 0.15 mmol).
Reactions were monitored by extracting 0.1 mL aliquots of the
reaction mixture periodically, which were analyzed by GLC.
Retention times for acetophenone and 2-phenylethanol are 3.9
and 4.2 min, respectively. The results were duplicated to
within (5% accuracy.
The full details of the crystallographic data are deposited
with the Cambridge Crystallographic Data Centre:
CCDC186508 (4b), CCDC186509 (4d ), CCDC186510 (5a ) and
CCDC186511 (5d ). These data can be obtained free of charge
via www.ccdc.cam.ac.uk/conts/retrieving.html, or from the
Cambridge Crystallographic Data Centre, 12, Union Road,
Cambridge CB2 1EZ, UK; fax: (+44)1223-336-033; or deposit@
ccdc.cam.ac.uk.
1
C
36H48N2Cl2P2Ru 741.1635, found 741.1642. Far-IR ν(Ru-
Cl): 305, 280 cm-1. Anal. Found: C, 54.05; H, 6.38; N, 3.12.
C
36H48N2Cl2P2Ru‚CH2Cl2 requires: C, 53.70; H, 6.09; N, 3.38.
B is [b e n zy l{2-(d ip h e n y lp h o s p h in o )e t h y l}a m in e ]-
r u th en iu m (II) Dich lor id e, 5d . Yield: 94%. 1H NMR (400
MHz, CDCl3): δ 2.50-2.75 (m, 6H, NCH2CH2P and NCH2-
CH2P), 3.15-3.25 (m, 2H, NCH2CH2P), 4.24 (m, 6H, C6H5CH2N
and NH), 6.94-7.28 (m, 30H, PPh2). 31P NMR (145 MHz,
CDCl3): δ 59.5. 13C NMR (90.5 MHz, CDCl3): δ 29.5 (virtual
triplet, 1J PC ) 12.7 Hz, NCH2CH2P), 46.1 (s, NCH2CH2P), 54.1
(s, C6H5 CH2N), 127.5-138.1 (aromatic region). HRMS: exact
mass calcd for C42H44Cl2N2P2Ru 808.1244, found 808.1264.
Far-IR ν(Ru-Cl): 305, 270 cm-1
.
Catalytic reactions were conducted using Radley’s 12-placed
reaction carousel. The apparatus is composed of two mounted
metal blocks, separated by a 5 cm gap. The bottom block is
positioned on a stirrer hotplate, and the temperature is
controlled via a digital thermostat. The top block is cooled by
circulating water and fitted with a central inlet/outlet for
vacuum and gas combined with a radial gas distribution to
the reaction tubes. The carousel can accommodate 12 glass
reaction tubes, with a reaction volume of 3-25 mL. The tubes
are fitted with screw caps, each containing an adjustable valve
to control the gas flow into the reaction tube. Addition and
extraction of solution to and from the reaction tube are
conducted via fitted rubber septa.
Ack n ow led gm en t. We thank King’s College London
for the support of a studentship (M.S.R.) and for the
X-ray facilities. We are grateful to EPSRC for a stu-
dentship (P.D.P.), and J ohnson Matthey plc for the gift
of RuCl3‚3H2O. We thank Professor S. E. Gibson (KCL)
for lending us access to GLC equipment.
Su p p or tin g In for m a tion Ava ila ble: Crystallographic
data of the structures of compounds 4b, 4d , 5a , and 5d are
given in the Supporting Information. This material is available
free of charge via the Internet at http://pubs.acs.org.
Typ ica l Ca ta lytic Ru n s. The ruthenium complexes (0.1
mmol, 1 mol %) were introduced into reaction tubes, each
equipped with stirrer bar. The tubes were then placed on a
OM0201314