Transition Met Chem (2011) 36:617–620
DOI 10.1007/s11243-011-9510-2
Synthesis, characterization, and biphasic ionic liquid media
1-hexene hydrogenation reaction
of RuCl (DMSO) (NC H CO Na-3)
2
2
5 4
2
2
Trino Su a´ rez
•
Bernardo Fontal
•
•
Joel E. Vielma
•
Marisela Reyes
Pedro Cancines
Fernando Bellandi
Juan C. D ´ı az
Yuraima Fonseca
•
•
•
Received: 7 April 2011 / Accepted: 3 June 2011 / Published online: 17 June 2011
Ó Springer Science+Business Media B.V. 2011
Abstract RuCl (DMSO) (NC H CO Na-3) is very soluble
2
De Souza [11] and Chauvin [12] in 1995. De Souza et al.
2
5
4
2
2
in the ionic liquid (IL) 1-n-butyl-3-methylimidazolium tetra-
investigated the Rh-catalyzed hydrogenation of cyclohexene
fluoroborate, [(BMIM)BF ]. The complex was prepared by
4
in 1-n-butyl-3-methylimidazolium [(BMI)BF ] with 40%
4
reacting RuCl (DMSO) with NC H CO Na-3, sodium nico-
2
conversion in 120 h and turnover number (TON) = 6,000
4
5
4
2
-1
tinate, in toluene, and was characterized by spectroscopic
methods. The complex catalyzes the hydrogenation of 1-hex-
and turnover frequency (TOF) = 50 h . Chauvin et al.
dissolved the cationic ‘‘Osborn complex’’ [Rh(nbd)(PPh ) ]-
2
3
ene (600 psi H , 100 °C) in a two-phase system consisting of
[PF ] (nbd = norbornadiene, PPh = triphenylphosphine) in
6 3
2
-
cyclohexane/[(BMIM)BF ] with 75% conversion in 24 h and
ionic liquids with weakly coordinating anions (e.g., [PF ] ,
6
4
-
-
modest substrate isomerization. The complex shows good sta-
bility and can be reused several times with little loss in activity.
[BF ] , and [SbF ] ) and used the obtained ionic catalyst
4 6
solutions for the biphasic hydrogenation of 1-pentene. In our
laboratory, we have performed a detailed study on the cata-
lytic hydrogenation of 1-hexene using the RuCl (TPPMS)
2
3
Introduction
(DMSO), (TPPMS = triphenilphosphine monosulfonate)
complex in the ionic liquid (BMI)PF and have found that
6
Recently, ionic liquids (ILs) have received worldwide aca-
demic and industrial attention as replacements for organic
solvents in catalysis [1]. Some of the attractive features of ILs
in catalysis include the versatility to act both as catalyst and
solvent, the profound effect that may have on solvation, sol-
volysis, reaction rate, selectivity minimizing side reactions,
and the opportunity of an easy recovery of the catalyst. Ionic
liquids possess useful physical characteristics as solvents in
biphasic catalytic reactions with organometallic complexes
the system catalyzes 1-hexene hydrogenation (500 psi H2,
100 °C) with 80% conversion in 24 h with TON = 480 and
TOF = 20 h [13]. Campbell et al. [14] studied the hydro-
-1
genation of 1,3-cyclohexadiene with ruthenium nanoparticles
(30 °C, 1.2 bar H , 90 min) in ionic liquid media with high
2
selectivity toward cyclohexene and showed TON = 70 and
-1
TOF = 46 h . Lee et al. [15] studied asymmetric catalytic
hydrogenation reactions using a Rh complex stabilized in
ionic liquid and found low catalytic activity loss during cat-
alyst reuse. In this work, we report the synthesis, character-
ization, and catalytic hydrogenation reaction in ionic liquid
media [(BMIM)BF ] of the novel RuCl (DMSO) (NC H
[2–9]. In general, transition metal-catalyzed hydrogenation
reactions in ionic liquids are particularly promising owing in
part to the large number of known ionic hydrogenation cata-
lyststhatareavailable [10]. The first successfulhydrogenation
reactions in ionic liquids were studied by the groups of
4
2
2
5 4-
CO Na-3) complex.
2
2
Experimental
T. Su a´ rez (&) ꢀ B. Fontal ꢀ J. E. Vielma ꢀ M. Reyes ꢀ
F. Bellandi ꢀ P. Cancines ꢀ J. C. D ´ı az ꢀ Y. Fonseca
Departamento de Qu ´ı mica, Facultad de Ciencias,
Laboratorio de Organomet a´ licos, Universidad de Los Andes,
M e´ rida 5101, Venezuela
Materials and methods
All manipulations were carried out under argon atmo-
e-mail: suarez@ula.ve
sphere, using standard Schlenk techniques. RuCl ꢀ3H O
3
2
123