Ruthenium complexes with 1,1′-biisoquinoline as ligands. Synthesis and hydrogenation activity

Article abstract of DOI:10.1016/S0022-328X(02)02193-9

The reaction of 1,1′-biisoquinoline (biisoq) with [Ru₂(biisoq)₂(CO)₄(CH₃-COO)] (CH₃COO). The same reaction in acetic acid gives the mononuclear [Ru(biisoq)₃] (CH₃COO)₂ complex instead of the expected [Ru(biisoq)(CO)₂(CH₃ COO)₂] compound. Starting from different precursors the following complexes containing the biisoq ligand [Ru(biisoq)₃](PF₆)₂, [Ru₂ (biisoq)₂(Cl)₄·NEt₃] and [Ru(η⁶-p-cymene)(Cl)(biisoq)]X [X: Cl, BPh₄] were synthesized and characterized. The X-ray structure of [Ru(η⁶-p-cymene)(Cl)(biisoq)][BPh₄] was also determined. Some of these complexes are catalytically active in the homogeneous hydrogenation of alkenes, alkynes and acetone in hydroalcoholic solvents. The better catalytic activity is shown in the hydrogenation of terminal and trans -olefins. Hex-1-ene is hydrogenated at 15 °C, using [Ru(η⁶-p-cymene)(Cl)-(biisoq)]Cl even if a reaction temperature of 40 °C is required to obtain a high yield in 6 h.

Full text of DOI:10.1016/S0022-328X(02)02193-9

Journal of Organometallic Chemistry 667 (2003) 197ꢀ208
/
www.elsevier.com/locate/jorganchem
Ruthenium complexes with 1,1?-biisoquinoline as ligands. Synthesis
and hydrogenation activity
Piero Frediani a,*, Carlo Giannelli a, Antonella Salvini a, Sandra Ianelli b
a Department of Organic Chemistry, University of Florence, Via della Lastruccia, 13, 50019 Sesto Fiorentino, Florence, Italy
b Department of General, Inorganic, Analytical and Physical Chemistry, University of Parma, Parco Area delle Scienze 17/a, 43100 Parma, Italy
Received 28 October 2002; received in revised form 11 December 2002; accepted 18 December 2002
Abstract
The reaction of 1,1?-biisoquinoline (biisoq) with [Ru2(CO)4(CH3COO)2]n gives the binuclear complex [Ru2(biisoq)2(CO)4(CH3-
COO)](CH3COO). The same reaction in acetic acid gives the mononuclear [Ru(biisoq)3](CH3COO)2 complex instead of the expected
[Ru(biisoq)(CO)2(CH3COO)2] compound. Starting from different precursors the following complexes containing the biisoq ligand
[Ru(biisoq)3](PF6)2, [Ru2(biisoq)2(Cl)4×
NEt3] and [Ru(h6-p-cymene)(Cl)(biisoq)]X [X: Cl, BPh4] were synthesized and character-
/
ized. The X-ray structure of [Ru(h6-p-cymene)(Cl)(biisoq)][BPh4] was also determined. Some of these complexes are catalytically
active in the homogeneous hydrogenation of alkenes, alkynes and acetone in hydroalcoholic solvents. The better catalytic activity
is shown in the hydrogenation of terminal and trans-olefins. Hex-1-ene is hydrogenated at 15 8C, using [Ru(h6-p-cymene)(Cl)-
(biisoq)]Cl even if a reaction temperature of 40 8C is required to obtain a high yield in 6 h.
# 2003 Published by Elsevier Science B.V.
Keywords: Homogeneous catalysis; Nitrogen ligands; Hydrogenation; Ruthenium; Complexes
1. Introduction
2. Result and discussion
Catalytic hydrogenations are widely used in many
processes of raw and fine chemical industry. One of the
main challenges would be to find new catalytic systems
achieving higher selectivity and low environmental
impact. The latter problem may be overcome using
water containing mixture as solvent [1,2]. Numerous
The biisoq ligand was obtained following the proce-
dure reported by Ashby et al. [6] with small modifica-
tions. The spectroscopic characterization (IR, 1H-NMR,
13C-NMR, MS) and the elemental analysis of the ligand
biisoq and the complexes synthesized are reported in
Tables 1ꢀ5.
/
examples of homogeneous hydrogenation of Cꢀ
/
C and
CꢀO double bonds in the presence of mono- and
/
2.1. Ruthenium complexes
binuclear ruthenium carbonyl carboxylato complexes
modified by nitrogen containing ligands like bipyridines
Using the methodologies reported for ruthenium
carbonyl carboxylato complexes with bipyridines and
phenantrolines [4,5,7] the binuclear complex [Ru2(bii-
soq)2(CO)4(CH3COO)](CH3COO)2 (1) was obtained
while the mononuclear [Ru(biisoq)(CO)2(CH3COO)2]
was not synthesized.
and phenantrolines have been reported in literature [3ꢀ
5]. Such complexes show a good catalytic activity in the
chemoselective hydrogenation of CꢀC double bonds
even in the presence of CꢀO double bonds The present
/
/
/
work deals with the synthesis of new complexes contain-
ing a 1,1?-biisoquinoline (biisoq) and provides an
account of their hydrogenation activity.
2.1.1. [Ru2(biisoq)2(CO)4(CH3COO)](CH3COO)
(1)
The reaction of [Ru2(CO)4(CH3COO)2]n [8] with (1),
in ethanol at the reflux temperature gave very small
yellow needles of [Ru2(biisoq)2(CO)4(CH3COO)](CH3-
* Corresponding author. Tel.: ꢁ
457-3531.
E-mail address: piero.frediani@unifi.it (P. Frediani).
/
39-055-457-3522; fax: ꢁ39-055-
/
0022-328X/02/$ - see front matter # 2003 Published by Elsevier Science B.V.
doi:10.1016/S0022-328X(02)02193-9

198
P. Frediani et al. / Journal of Organometallic Chemistry 667 (2003) 197ꢀ208
/
Table 1
IR spectra of the synthesized compound
a
Compound
Biisoq
Code Absorptions (cmꢂ1
)
3043 (m, aromatic Cꢁ
stretch), 1556 (s, CꢀC ring stretch), 1491 (m), 1373 (m), 1317 (s), 1136 (m)
3119 (w, aromatic CꢁH stretching), 3080 (w, aromatic CꢁH stretching), 3066 (w, aromatic Cꢁ
stretching), 2936 (vw, methyl CꢁH stretching), 2028 (s, CꢂO stretching), 1975 (m, Cꢂ
stretching), 1945 (sh, CꢂO stretching), 1940 (s, CꢂO stretching), 1911 (w, CꢂO stretching), 1623
(m, CꢀO stretching of the carboxylato anion), 1570 (s, CꢀO asymmetric stretching), 1438 (s, Cꢀ
O symmetric stretching)
(2a) 3001 (m, aromatic CꢁH stretching), 2927 (m, methyl Cꢁ
stretching), 1695 (m, CꢀC ring stretch), 1602 (m, CꢀO stretching of the carboxylato anion)
(2b) 3066 (m, aromatic CꢁH stretching), 1618 (w CꢀC ring stretch), 1587 (m, CꢀC ring stretch), 1550
(w, CꢀC ring stretch), 1536 (w, CꢀC ring stretch), 1500 (w, CꢀC ring stretch), 843 (vs, Pꢁ
vibrations), 557 (s, PꢁF vibrations)
(3a) 3053 (m, aromatic CꢁH stretching), 2955 (m, aliphatic Cꢁ
stretching), 1916 (s), 1586 (s CꢀC ring stretch), 1529 (s, Cꢀ
stretch), 1404 (m CꢀC ring stretch), 1345 (s, CꢁN stretching), 283 (w, Ruꢁ
RuꢁCl vibrations)
(4a) 3045 (m, aromatic Cꢁ
stretching), 2879 (w, aliphatic Cꢁ
stretch), 1426 (m, CꢁH asymmetric bending), 1349 (m, Cꢁ
diethyl ether CꢁO stretching)
(4b) 3054 (s, aromatic CꢁH stretching), 2975 (m, aliphatic Cꢁ
stretching), 2868 (vw, aliphatic CꢁH stretching), 1598 (s, Cꢀ
stretch), 1476 (m, CꢀC ring stretch), 1423 (s, CꢁH asymmetric bending), 1348 (s, Cꢁ
symmetric bending), 1260 (w), 1155 (w), 1030 (w)
/
H stretching), 1619 (m, Cꢀ
/
N stretching), 1581 (m), 1579 (s, Cꢀ
/
C ring
/
[Ru2(biisoq)2(CO)4(CH3COO)](CH3COO) (1)
/
/
/
H
/
/
/
O
/
/
/
/
/
/
[Ru(biisoq)3](CH3COO)2
[Ru(biisoq)3](PF6)2
/
/
H stretching), 2857 (w, methyl CꢁH
/
/
/
/
/
/
/
/
/
/F
/
Ru2(biisoq)2(Cl)4×
/
NEt3
/
/
H stretching), 2930 (m, aliphatic Cꢁ
C ring stretch), 1441 (m, CꢀC ring
Cl vibrations), 228 (w,
/
H
/
/
/
/
/
/
/
[Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
0.5Et2O
/
/
H stretching), 2962 (m, aliphatic Cꢁ
H stretching), 1617 (m, Cꢀ
H symmetric bending), 1156 (m,
/
H stretching), 2928 (w, aliphatic Cꢁ
/
H
/
/
C ring stretch), 1586 (m, CꢀC ring
/
/
/
/
[Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4]
/
/
H stretching), 2925 (m, aliphatic Cꢁ
/
H
/
/
C ring stretch), 1578 (s, CꢀC ring
/
/
/
/
H
a
All spectra were performed in KBr pellet.
COO) (1) with a 56.5% yield. The complex is insoluble in
hexane, benzene, acetone, methanol, and slowly dis-
solves in DMSO, tetrahydrofuran (THF) and DMF.
The carbonyl stretchings in the IR spectrum of (1),
according to those reported for Ru2(CO)4(CH3-
COO)2(PBu3)2 [8] are an indication that each carbonyl
group is terminal. The mass spectrum in DMF per-
formed immediately after the dissolution of the complex
suggests the formulation proposed. However, it reacts
with coordinating solvents after a few hours at room
temperature as shown by the 1H-NMR spectra in
DMSO-d6 or DMF-d7 revealing the resonances of the
free ligand. The IR and MS data suggest the structure
reported in Fig. 1.
2.1.2. [Ru(biisoq)3](CH3COO)2 (2a) and
[Ru(biisoq)3](PF6)2 (2b)
Attempts to prepare Ru(biisoq)(CO)2(CH3COO)2
were carried out following the procedure reported by
Frediani et al. [4] for mononuclear ruthenium carbonyl
carboxylato complexes with phenantroline or bipyri-
dine. A suspension of biisoq and [Ru2(CO)4(CH3-
COO)2]n (1:1 ligandꢀruthenium atoms) in acetic acid
/
Table 2
MS spectra of the synthesized compound
c
Compound
Code Peak (m/z)
a
Biisoq
256 (55%, [M]ꢁ); 255 (100%, [Mꢂ
/
1]ꢁ); 227 (10%); 128 (80%, [C9H6N]ꢁ); 114 (40%); 100
(30%); 75 (20%); 51 (20%)
886.9 (100%, [Ru2(biisoq)2(CO)4(CH3COO)]ꢁ), 701.0 (12%), 615.1 (23%), 473.0 (24%,
[Ru(biisoq)(CO)2(CH3COO)]ꢁ), 359.0 (18%), 322.0 (23%)
b
[Ru2(biisoq)2(CO)4(CH3COO)](CH3COO)
(1)
[Ru(biisoq)3](PF6)2
[Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4]
(2b) 1015.1 (10%, {[Ru(biisoq)3](PF6)}ꢁ), 901.1 (6%), 892.1 (6%), 435.1 (100%, {[Ru(biisoq)3]}2ꢁ
)
a
(4b) 527.0 (100%, [Ru(h6-p-cymene)(Cl)(biisoq)]ꢁ
)
a
a
Performed from acetone solution.
Performed from DMF solution.
The center of the isotopic peaks is reported; the simulated patterns are perfectly superimposable to those experimentally detected.
b
c

Table 3
1H-NMR spectra
Compound
Code Chemical shift (ppm)
7.55 [ddd, 3J7,8ꢃ3
a
Biisoq
/
J
7?,8?ꢃ
/
8.5, 3J7,6ꢃ3
H]; 8.09 [d, J5,6ꢃ3
/
J
7?,6?ꢃ
6?,5?ꢃ
5?,6?ꢃ
6.8 (m, 2H); 7.3ꢀ8.8 (m, 34H)
/
6.8, 4J7,5ꢃ4
8.3, 3J6,7ꢃ3
8.3 Hz, 2H, C(5)ꢁ
/
J
7?,5?ꢃ
/
1.2 Hz, 2H, C(7)ꢁ
6.8, 4J6,8ꢃ4
6?,8?ꢃ
H, C(5?)ꢁ
H]; 8.68 [d, J3,4ꢃ3
/
H, C(7?)ꢁ
/
H]; 7.74 [dd, 3J8,7ꢃ3
H, C(6?)ꢁ
3?,4?ꢃ5.6 Hz, 2H, C(3)ꢁ
/
J
8?,7?ꢃ
H]; 7.97 [d, 3J4,3ꢃ3
H, C(3?)ꢁ
/
8.5, 4J8,6
ꢃ
/
J
8?,6?ꢃ
4?,3?ꢃ
H]
/
1.1 Hz,
2H, C(8)ꢁH, C(8?)ꢁ
Hz, 2H, C(4)ꢁH, C(4?)ꢁ
(2a) 1.26 (s, 6H, CH3COO); 6.5ꢀ
(2b) 6.8ꢀ7.2 (m, 2H); 7.6ꢀ8.8 (m, 34H)
(3a) 0.9 (t, 3Jꢃ
6.8 Hz, 9H, NꢁCH2ꢁCH3); 1.25 (m, 6H, Nꢁ
(d, Jꢃ6.3 Hz, 1H); 7.30ꢀ8.20 (m, 16H); 10.20 [d, Jꢃ6.0 Hz, 1H, C(3)ꢁ
10.50 [d, Jꢃ6.0 Hz, 1H, C(3)ꢁH]
(4a) 0.89 (d, 3Jꢃ
7.0 Hz, 3H, CHꢁCH3); 0.94 (d, Jꢃ
7.0 Hz, 1H, ꢁCH(CH3)2]; 3.46 [q, Jꢃ
/
/
H]; 7.79 [ddd, 3J6,5ꢃ3
/
J
/
/
J6?,7?ꢃ
/
/
J
/
1.1 Hz, 2H, C(6)ꢁ
/
/
/
J
/
5.6
3
3
/
/
/
J
/
/
/
/
J
/
/
/
b
[Ru(biisoq)3](CH3COO)2
a
[Ru(biisoq)3](PF6)2
/
/
/
/
b
Ru2(biisoq)2(Cl)4×
/NEt3
/
/
/
/
CH2ꢁ
/
CH3); 6.90 (d, Jꢃ
/6.3 Hz, 1H); 6.98 (d, Jꢃ
/6.3 Hz, 1H); 7.06 (d, Jꢃ
/
6.3 Hz, 1H); 7.09
H];
/
/
/
/
H]; 10.30 [d, Jꢃ
/
6.0 Hz, 1H, C(3)ꢁ
/
H]; 10.40 [d, Jꢃ6.0 Hz, 1H, C(3)ꢁ
/
/
/
/
[Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
0.5Et2O
/
/
/
/
7.0 Hz, 3H, CHꢁ
/
CH3); 1.18 [t, 3Jꢃ
7.0 Hz, 2H, O(CH2ꢁCH3)2]; 6.10ꢀ
8.3 Hz, 1H, C(7)ꢁ
8.3 Hz, 1H, C(6)ꢁ
H]; 7.88 [d, 3J8,7
H]; 8.19 [d, 3J4?,3?ꢃ H]; 8.31 [d, 3J4,3
6.0 Hz, 1H, C(4?)ꢁ
6.0 Hz, 1H, C(3)ꢁH]
6.8 Hz, 3H, CHꢁ
CH3); 2.69 [qq, 3Jꢃ6.8, 3Jꢃ
H]; 6.93 [m, 8H, B(C6H5)4: C(m)ꢁH]; 7.34 [m, 8H, B(C6H5)4: C(o)ꢁ
/
7.0 Hz, 3H, O(CH2ꢁ
/
CH3)2]; 1.95 (s, 3H, CH3ꢁ
C6H4ꢁ, ABCD spin system, 4H); 7.45
8.3 Hz, 1H, C(8?)ꢁH]; 7.72 [dd,
8.3 Hz, 1H, C(8)ꢁ 8.3
H]; 7.99 [d, 3J5?,6?ꢃ
6.0 Hz, 1H, C(4)ꢁ
H]; 9.74 [d, 3J3?,4?ꢃ
/
C6H4ꢁ); 2.62
/
3
?
b
3
3
3
[qq, Jꢃ
/
7.0, Jꢃ
/
/
/
/
/
/
6.54 (m, CH3ꢁ
/
/
3
3
3
3
3
[dd, J7?,6?ꢃ
3J6?,7?ꢃ8.3, 3J6?,5?ꢃ
Hz, 1H, C(5?)ꢁ
H]; 8.15 [d, 3J5,6
6.0 Hz, 1H, C(3?)ꢁ
(4b) 0.94 (d, 3Jꢃ
C6H4ꢁ
3J7?,8?ꢃ
C(8?)ꢁ
H]; 7.95 [ddd, 3J6?,5?ꢃ
3J8,7 H]; 8.25 [d, 3J4?,3?ꢃ
8.7 Hz, 1H, C(8)ꢁ
H, C(5?)ꢁ 6.5 Hz, 1H, C(3?)ꢁ
H]; 9.41 [d, 3J3?,4?ꢃ
8.3, J7?,8?ꢃ
/
8.3 Hz, 1H, C(7?)ꢁ
H]; 7.87 [dd, 3J6,7
8.3 Hz, 1H, C(5)ꢁ
/
H]; 7.60 [dd, J7,6
ꢃ/
8.3, J7,8
ꢃ/
/H]; 7.68 [d, J8?,7?ꢃ
/
/
/
/
8.3 Hz 1H, C(6?)ꢁ
/
ꢃ/
8.3, 3J6,5
ꢃ/
/
ꢃ/
/
/
/
ꢃ
/
/
/
/
ꢃ
/
/
/
3
/H]; 9.75 [d, J3,4
ꢃ
/
/
[Ru(h6-p-cymene)(Cl)(bii-
soq)][B(C6H5)4]
/
7.0 Hz, 3H, CHꢁ
/
CH3); 1.01 (d, Jꢃ
/
/
/
/
6.8 Hz, 1H, ꢁ
/
CH(CH3)2]; 5.85ꢀ
/
6.40 (m, 4H, CH3ꢁ
H]; 7.66 [ddd,
H]; 7.89 [d, J8?,7?ꢃ8.7 Hz, 1H,
1.0 Hz, 1H, C(6)ꢁH]; 8.11 [d,
H]; 8.35 [d, 3J5,6ꢃ3
5?,6?ꢃ7.6 Hz, 2H, C(5)ꢁ
/
3
?
a
/
, ABCD spin system); 6.76 [m, 4H, B(C6H5)4: C(p)ꢁ
/
/
/
3
4
3
3
4
3
/
8.7, J7?,6?ꢃ
/6.8, J7?,5?ꢃ
/
1.2 Hz, 1H, C(7?)ꢁ
6.8, 4J6?,8?ꢃ
6.5 Hz, 1H, C(4?)ꢁ
/
H]; 7.77 [ddd, J7,8
1.0 Hz, 1H, C(6?)ꢁ
H]; 8.28 [d, 3J4,3
ꢃ
/
/
8.7, J7,6
H]; 8.03 [ddd, 3J6,5
6.5 Hz, 1H, C(4)ꢁ
6.5 Hz, 1H, C(3)ꢁH]
ꢃ/
7.0, J7,5
ꢃ
/
/
1.2 Hz, 1H, C(7)ꢁ
/
/
/
/
7.6, 3J6?,7?ꢃ
/
/
ꢃ
7.6, 3J6,7 7.0, 4J6,8
ꢃ/
ꢃ/
/
ꢃ/
/
/
/
ꢃ/
/
/
J
/
/
3
/
/
/
H]; 9.51 [d, J3,4
ꢃ
/
/
a
Solvent acetone-d6.
Solvent CDCl3.
b

200
P. Frediani et al. / Journal of Organometallic Chemistry 667 (2003) 197ꢀ208
/
was kept at the reflux temperature for 4 days avoiding
direct exposure to sunlight.
A mixture of different complexes was obtained
instead of the expected Ru(biisoq)(CO)2(CH3COO)2.
By using preparative TLC on aluminium oxide we were
able to isolate a purple fraction containing the complex
[Ru(biisoq)3](CH3COO)2 (2a).
By a methatesis reaction of (2a) with NH4PF6 (1:2
molar ratio) in water, [Ru(biisoq)3](PF6)2 (2b) was
obtained as small purple needles.
2.1.3. Ru2(biisoq)2(Cl)4×
/
NEt3 (3a) and Ru(biisoq)(m2-
CH3COO)2 (3b)
Using the procedure reported for Ru(BINAP)(m2-
CH3COO)2 [9] a mixture of [Ru(Cl)2(h4-1,5-COD)]n
[10] and 1 (molar ratio 1:1) in the presence of an excess
of triethylamine was heated in toluene at 140 8C. The
binuclear complex Ru2(biisoq)2(Cl)4×
/
NEt3 (3a) was
obtained.
The methatesis reaction of 3a with sodium acetate
gave the corresponding Ru(biisoq)(m2-CH3COO)2 com-
plex 3b, subsequently seen to decompose during the
purification. The presence of 3b was deduced from an
1H-NMR by the characteristic signals of C(3)ꢁ
C(3?)ꢁH of the coordinated biisoq and the signals of the
acetate ligands in a 1:3 ratio.
/H and
/
2.1.4. [Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
/
0.5Et2O
(4a) and [Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4]
(4b)
Mononuclear arene ruthenium complexes [Ru(h6-p-
cymene)(Cl)(biisoq]X (X: Clꢂ, B(C6H5)4ꢂ) were success-
fully synthesized from the commercial [Ru(h6-p-cyme-
ne)(Cl)2]2.
Following the procedure reported by Mashima et al.
[11] (Scheme 1) a solution of [Ru(h6-p-cymene)(Cl)2]2
and biisoq (ligandꢀ
benzene was heated at 55 8C giving the complex
0.5Et2O (4a) with a
/
Ruꢃ
/
1 molar ratio) in ethanolꢀ
/
[Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
/
1
98% conversion evaluated by H-NMR.
The complex was purified by flash chromatography
and the solution was slowly dropped in diethyl ether
under vigorous stirring. The expected complex was
obtained in the form of very small light orange needles,
soluble and stable in water.
1
The H-NMR spectrum showed signals attributable
to diethyl ether in a complexꢀ
agreement with the following formulation: [Ru(h6-p-
cymene)(Cl)(biisoq)](Cl)×0.5Et2O (4a). The chemical
/ether ratio of 2:1 in
/
shifts of diethyl ether suggested that it was present as
inclusion in the crystals of 4a and not directly coordi-
nated to the metal.
By reaction of a solution of 4a with NaB(C6H5)4
(molar ratio 1:1.5) at reflux temperature the product
[Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4]
synthesized as very small orange needles (75% yield).
(4b)
was

P. Frediani et al. / Journal of Organometallic Chemistry 667 (2003) 197ꢀ
/208
201
Table 5
Elemental analysis, decomposition or melting temperature
a
Compound
Code
M.p. (8C)
Elemental analysis (%)
C
H
N
Biisoq
158ꢀ
/
160
84.10 (84.35)
55.42 (55.81)
70.10 (70.50)
55.46 (55.92)
52.20 (52.67)
59.70 (60.10)
73.32 (73.80)
4.72 (4.72)
2.83 (3.20)
4.30 (4.28)
3.42 (3.13)
4.31 (4.10)
4.99 (5.21)
5.33 (5.48)
10.69 (10.93)
5.58 (5.92)
8.52 (8.51)
7.55 (7.25)
7.12 (7.31)
4.44 (4.67)
3.23 (3.31)
[Ru2(biisoq)2(CO)4(CH3COO)](CH3COO)
[Ru(biisoq)3](CH3COO)2
[Ru(biisoq)3](PF6)2
(1)
(2a)
(2b)
(3a)
(4a)
(4b)
Ru2(biisoq)2(Cl)4×NEt3
/
[Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
/0.5Et2O
150ꢀ
/
155
b
b
[Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4]
215ꢀ
/
220
a
Calculated values in parenthesis.
Decompose.
b
Table 6
X-ray data of [Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4] (4b): summary
of crystal data collection parameters
Formula
Fw
Space group
C52H36BClN2Ru
836.16
P21/n
˚
a (A)
11.843(9)
19.827(16)
18.370(9)
100.75(1)
4238(21)
4
˚
b (A)
˚
c (A)
b (8)
3
V (A )
˚
Fig. 1. Suggested structure of [Ru2(biisoq)2(CO)4(CH3COO)](CH3-
COO).
Z
r (g cmꢂ3
m (mmꢂ1
Crystal size (mm3)
Number of independent reflections
)
1.296
0.470
)
0.20ꢄ/0.32ꢄ
/
0.39
The complex was pure enough to be used as a catalyst.
However, it was possible to crystallize it through a slow
7663 [Rint
4656
ꢃ
/
0.0808]
Number of reflections [I ꢀ
/2s(I)]
evaporation of an acetoneꢀ
dichloromethaneꢀethanol solutions obtaining dark red
micro crystals.
/
ethanol or THFꢀethanol or
/
u Range (8)
Number of parameters
1.90ꢀ
494
/
25.29
/
R [I ꢀ
/
2s(I)]
0.0675
0.1681
wRF 2
Crystals suitable for X-ray structure determination
were obtained by slow diffusion of a methanol solution
of NaB(C6H5)4 in a methanol solution of 4a.
1
The H-NMR signals of the chelate biisoq present in
Table 7
X-ray data of [Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4] (4b): selected
interatomic distances (A), angles (8), and torsion angles (8)
both complexes showed a different pattern with respect
to the free ligand because the two isoquinoline rings
were not equivalent. These data confirm the presence of
biisoq chelate to ruthenium in an atropisomeric form
(see Fig. 2) with a low rate of interconversion. The
˚
Bond lengths
Ruꢁ
Ruꢁ
Ruꢁ
Ruꢁ
/
Cl
2.387(3)
2.070(5)
2.092(9)
1.680(10)
/N
/N?
coalescence of the C(3)ꢁ
at 110 8C.
As shown for phenantrolines and bipyridines chelate
to ruthenium complexes [5,7] the C(3)ꢁH and C(3?)ꢁ
/
H, C(3?)ꢁ/H signals was reached
a
/G
Bond angles
NꢁRuꢁN?
N?ꢁRuꢁCl
NꢁRuꢁ
NꢁRuꢁ
N?ꢁ
ClꢁRuꢁ
/
/
75.8(2)
84.0(2)
/
/H
/
/
protons were shifted at higher field than in the free
/
/Cl
87.0(2)
/
/G
131.2(1)
133.1(2)
127.5(1)
ligand.
/
Ruꢁ
/
G
The signals of the p-cymene protons of these com-
plexes were interesting if compared with those of the
starting [Ru(h6-p-cymene)(Cl)2]2 [12].
/
/G
Torsion angles
NꢁC1ꢁC1?ꢁN?
C8aꢁC1ꢁC1?ꢁC8a?
C8ƒꢁC7ƒꢁC1ƒꢁ
C9ƒꢁC7ƒꢁC1ƒꢁ
/
/
/
ꢂ
/
24.8(7)
/
/
/
ꢂ
/
34.5(9)
. The two methyl protons of the isopropyl group of 4a
and 4b were not chemically equivalent even if they
showed the same chemical shift in the starting
complex;
/
/
/
C6ƒ
C6ƒ
157.08(7)
/
/
/
ꢂ
/
75.6(8)
a
G represents the centeroid of the h6-p-cymene.

202
P. Frediani et al. / Journal of Organometallic Chemistry 667 (2003) 197ꢀ
/208
Scheme 1.
. The aromatic proton shifts of 4a and 4b are at lower
frequencies than in the free p-cymene [12] due to the
h6 coordination. They show a AA?XX? spin system in
the starting complex but in the biisoq containing
complex they show an ABCD spin system.
enhancement of the activity of 4a and 4b giving TOF
values of 63.9 and 118.2, respectively (Table 9).
The catalytic activity of 4a and 4b, was found to be
dependent on the nature of the counterion, as previously
reported in the literature [7] for other ruthenium
complexes. In fact 4a showed a better activity than 4b,
at temperatures higher than 40 8C while at lower
temperatures the reverse is true.
These attributions were confirmed by selective decou-
1
pling and by H-NMR COSY spectrum.
An increase of the hydrogen pressure from 15 to 50
atm raised the TOF of hex-1-ene hydrogenation from
1.3 to 151.5 hꢂ1 suggesting the formation of a ruthe-
nium hydride complex was required in the first step of
the process (Table 10).
The influence of substrate concentration was tested
using 4a in the range between 0.712 and 5.7 M. A
surprising behavior was noted with the higher yield
(98.8%) being obtained for a concentration of 1.07 M
while at higher olefin concentration the yield decreased
down to 7.5% hex-1-ene concentration of 5.7 M (Table
11). This behavior suggests the formation of a p-olefin
ruthenium complex hindering the coordination of the
hydrogen to the catalyst. As a consequence the rate of
hydrogenation is reduced.
2.1.5. X-ray molecular structure of [Ru(h6-p-
cymene)(Cl)(biisoq)][B(C6H5)4] (4b)
The molecular structure of the cationic complex is
reported in Fig. 3. The cation displays a three-legged
piano-stool geometry involving an h6-p-cymene group,
a Cl atom, and the N, N? atoms of the biisoq chelate
ligand. Assuming the arene occupies three facial sites,
the coordination geometry can be also described as a
distorted octahedral. The Ru atom, is p-bonded to the
p-cymene ligand with a separation between the arene
˚
plane and the metal center of 1.680(10) A. Due to
restraints of the NꢁN? chelate, the five-membered ring
RuꢁNꢁC1ꢁC1?ꢁN? is not planar (C1 and C1? atoms are
displaced by ꢂ0.128(5) and 0.118(5) A, respectively,
from the mean plane through the other three atoms)
/
/
/
/
/
˚
/
The catalyst having the higher activity at 60 8C, 4a,
was also tested in the hydrogenation of other substrates
such as internal alkenes, alkynes and ketones (Table 12).
This complex showed a good activity and an appreciable
˚
with a bit angle of 75.8(2)8. The Ruꢁ
/
N 2.070(5) A and
N? 2.090(9) A distances are essentially equal and in
agreement with those found in related structures [13].
The NꢁC1ꢁC1?ꢁN? torsion angle of ꢂ24.8(7)8 that
describes the twist of the biisoq ligand is comparable
with the ꢂ24.1(6)8 value found in literature for the
˚
Ruꢁ
/
/
/
/
/
selectivity for the hydrogenation of Cꢀ/C double bond.
The trans alkenes were easier to hydrogenate than the
cis isomers. Furthermore the catalytic activity in the
hydrogenation of terminal olefin was higher than for
internal ones. Aromatic olefin was more difficult to
hydrogenate than aliphatic alkene.
/
biisoq Ru-complexes [14] and the two halves of the
ligand, which are not planar, form between them a
dihedral angle of 39.5(1)8. In the h6-arene ring the Cꢁ
/C
˚
1.440(10) A,
bond distances fall in the range 1.348(8)ꢀ
/
˚
C arene ranging from 2.164(8) to 2.217(7) A.
The reluctance of this catalyst to hydrogenate the cis
isomers was confirmed by the hydrogenation of cyclo-
hexene. It was obtained with almost the same yield of
cis-hex-3-ene.
the Ruꢁ
/
2.2. Catalytic activity of ruthenium complexes
The hydrogenation of phenylacetylene under the same
conditions has been obtained with very low yield. In fact
only 3.1% of styrene was formed together with a 1.6% of
ethylbenzene.
The complexes 1, 4a and 4b were tested in the catalytic
hydrogenation of hex-1-ene (Table 8) using a hydro-
alcoholic solvent. All the catalysts showed an high
catalytic activity in the hydrogenation of hex-1-ene.
Complex 4a was catalytically active even at 15 8C with a
TOF of 4.5 hꢂ1. However, increasing the reaction
temperature up to 40 8C resulted in a significant
A Cꢀ/C double bond conjugated with a carbonyl or
carboxylato group was hydrogenated with a low effi-
ciency as indicated by the case of trans-4-phenylbut-3-

P. Frediani et al. / Journal of Organometallic Chemistry 667 (2003) 197ꢀ
/208
203
Fig. 2. 1H-NMR of (a) biisoq (acetone-d6, 9.6ꢀ
/
7.5 ppm), (b) [Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4] (4b) (acetone-d6, 9.6ꢀ
0.5Et2O (4a) (CDCl3, 7.0ꢀ0.5 ppm).
/
7.5 ppm), (c) [Ru(h6-p-
cymene)(Cl)2]2 (CDCl3, 7.0ꢀ
/
0.5 ppm), (d) [Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
/
/

204
P. Frediani et al. / Journal of Organometallic Chemistry 667 (2003) 197ꢀ208
/
Table 10
Catalytic hydrogenation of hex-1-ene to hexane in the presence of
[Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
/
0.5Et2O (4a)
pH2
Hexane
a
Yield (%)
TOF (hꢂ1
)
5
15
30
50
0.0
0.8
0.0
1.3
4.7
93.1
7.6
151.5
Influence of hydrogen pressure. Substrate 8.55 mmol; catalyst 8.755
mmol; solvent: methanol 4 mlꢁwater 2 ml; reaction time 6 h, T 60 8C.
TOF: turn over frequency (mol substrate) (mol-Ruꢄ
h)ꢂ1
/
Fig. 3. Molecular structure of cation [Ru(h6-p-cymene)(Cl)(biisoq)]ꢁ
.
a
/
.
Hydrogen atoms and B(C6H5)4ꢂ are omitted for clarity.
In the complexes synthesized 4a and 4b for each
hydrogens of the two isoquinoline rings we observe
different resonances (see Fig. 2) in agreement with an
asymmetric structure. These data confirm that the
energy barrier for the cis rotation of the ligand is higher
than in the free ligand and the kinetic of the inter-
conversion at room temperature is low in the NMR time
scale.
The X-ray structure of [Ru(h6-benzene)(Cl)(biisoq)]-
[PF6] [13] was previously reported in the literature. The
1H-NMR data of the benzene derivative are in agree-
ment with those reported in this paper for the p-cymene
Table 8
Catalytic hydrogenation of hex-1-ene
a
Complex
Code Yield
(%)
TOF
(hꢂ1
)
[Ru2(biisoq)2(CO)4(CH3COO)](CH3COO) (1)
[Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
0.5Et2O
87.3
(4a) 99.1
142.2
161.2
/
[Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4]
(4b) 78.7
128.1
Substrate 8.55 mmol; catalyst 8.755 mmol; solvent: methanol 4 mlꢁ
/
water 2 ml; pH2 100 atm (at 20 8C); reaction time 6 h; T 60 8C.
a
TOF: turn over frequency (mol substrate) (mol-Ruꢄ .
h)ꢂ1
/
en-2-one (benzylidenacetone) and 2-methylbut-2-enoic
acid (tiglic acid); the CꢀO double bond was not reduced.
O double bond to secondary
Table 11
Catalytic hydrogenation of hex-1-ene to hexane in the presence of
/
The reduction of a Cꢀ
/
[Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
/
0.5Et2O (4a)
alcohol was obtained with low yield at 140 8C.
Hex-1-ene (M)
Hexane
a
Yield (%)
TOF (hꢂ1
)
3. Conclusion
0.712
1.070
1.420
2.850
5.700
3.3
98.8
93.1
67.9
7.5
2.6
120.1
151.5
221.0
48.6
The free biisoq is not a chiral ligand like BINAP
because the two atropisomeric forms freely convert
through an anti 1,1? rotation [6]. The ligand chelated
to a metal may be able, without breaking bonds, to
convert only through a cis 1,1? rotation [6]: it may be
hindered by the steric encumbrance of the 8,8? hydrogen
atoms.
Influence of substrate concentration. Catalyst 8.755 mmol; solvent:
methanol 4 mlꢁwater 2 ml; pH2 50 atm (at 20 8C); reaction time 6 h,
T 60 8C.
/
a
TOF: turn over frequency (mol substrate) (mol-Ruꢄ .
h)ꢂ1
/
Table 9
Catalytic hydrogenation of hex-1-ene in the presence of [Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×0.5Et2O (4a) or [Ru(h6-p-cymene)(Cl)(biisoq)](BPh4) (4b)
/
a
Catalyst
[Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
Code
T (8C)
Yield (%)
TOF (hꢂ1
)
/0.5Et2O
(4a)
(4a)
(4a)
(4a)
(4b)
(4b)
(4b)
15
40
60
80
40
60
80
2.8
39.3
99.1
100
4.5
63.9
161.2
162.8
118.2
128.1
151.1
[Ru(h6-p-cymene)(Cl)(biisoq)](BPh4)
72.6
78.7
92.8
Substrate 8.55 mmol; catalyst 8.755 mmol; solvent: methanol 4 mlꢁwater 2 ml; pH2 100 atm (at 20 8C); reaction time 6 h.
/
a
TOF: turn over frequency (mol substrate) (mol-Ruꢄ .
h)ꢂ1
/

P. Frediani et al. / Journal of Organometallic Chemistry 667 (2003) 197ꢀ
/208
205
Table 12
Catalytic hydrogenations using [Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
/0.5Et2O (4a)
a
Substrate
Product
Hydrogenation yield (%)
TOF (hꢂ1
)
Hex-1-ene
cis-Hex-2-ene
Hexane
Hexane
99.1
38.8
98.5
16.3
94.2
12.0
1.2
161.2
63.1
160.3
26.6
153.2
19.5
2.0
trans-Hex-2-ene
cis-Hex-3-ene
Hexane
Hexane
trans-Hex-3-ene
Cyclohexene
Hexane
Cyclohexane
trans-2-Methylbut-2-enoic acid
trans-4-Phenyl-3-buten-2-one
Styrene
2-Methylbutanoic acid
4-Phenylbutan-2-one
Ethylbenzene
9.9
16.3
85.1
7.6
52.3
3.1
Phenylacetylene
Styrene
Ethylbenzene
Isopropyl alcohol
1.6
10.5
Acetoneb
77.1
Substrate 8.55 mmol; catalyst 8.755 mmol; solvent: methanol 4 mlꢁ
/
water 2 ml; pH2 100 atm (at 20 8C); reaction time 6 h; T 60 8C.
a
TOF: turn over frequency (mol substrate) (mol-Ruꢄ .
h)ꢂ1
/
b
T 140 8C
analog, confirming the asymmetric structure of the
mononuclear complexes 4a and 4b.
film layer) using a PC and the Shimadzu CLASS 5000 v
2.20 program.
These complexes are soluble and stable in hydroalco-
holic solvents and they show a good catalytic activity in
the hydrogenation of alkenes. They are able to selec-
MS analyses of the ruthenium complexes were carried
out using a PE Biosystems’ Mariner ESI/time-of-flight
mass spectrometer.
tively hydrogenate a Cꢀ
/
C double bond in presence of a
Elemental analyses were carried out using a Perkinꢀ
Elmer Series II CHNS/O analyzer.
/
carbonyl or carboxylato double bond.
4.1. Materials
4. Experimental
All preparations and manipulations were routinely
performed under a dry nitrogen atmosphere using
Schlenk tube techniques.
IR spectra were recorded with a FTIR PerkinꢀElmer
1760-X instrument, using a PC and the PE-SPECTRA
V2000 program. KBr pellets were used for solid.
/
1H-NMR and 1H-NMR COSY spectra were recorded
at 299.945 MHz on a Varian VXR 300 using tetra-
methylsilane as external standard. 13C-NMR spectra
were recorded at 75.429 MHz on a Varian VXR 300,
using tetramethylsilane as external standard. All 13C-
NMR spectra were acquired using a broad band
decoupler. 1H, 13C-NMR, HETCOR spectra were
recorded using the pulse sequence reported by Varian.
Flash chromatographic columns were filled with
Acetone, methanol, THF, diethyl ether, toluene,
ethanol, benzene and chloroform were purified and
stored using the method reported in literature [17].
Diisopropylamine (Aldrich, 99.5%) was refluxed for 3
h on CaH2, than distilled (boiling point (b.p.) 84 8C) and
stored under nitrogen. Isoquinoline (Aldrich 97%)
˚
(melting point (m.p.) 26 8C) was kept on activated 4 A
molecular sieves for 3 h than distilled (b.p. 86 8C/3
mmHg) and stored under nitrogen. Hexamethylpho-
sphoramide (HMPA) (Merk, 99%) was dried for 2 days
neutral or basic aluminium oxide Merck 35ꢀ
or silica gel Merck 35ꢀ70 mesh.
GC analyses were performed using a Shimadzu GC14
instrument for packed columns or a PerkinꢀElmer 8320
/70 mesh
on CaO than distilled (b.p. 100ꢀ
stored under nitrogen.
Hex-1-ene and cyclohexene were purified by elution
through a neutral Al2O3 (70ꢀ230 mesh) chromato-
/
105 8C/6 mmHg) and
/
/
/
apparatus for capillary columns. All instruments were
equipped with FID detectors. The following packed
columns (2 m length, 1/8 in.) were employed: SQ
graphic column, then distilled and stored under nitro-
gen.
Styrene and phenylacetylene were distilled under
vacuum (12 mmHg) and stored under nitrogen.
[Ru2(CO)4(CH3COO)2]n [8] and [Ru(Cl)2(h4-1,5-
COD)]n [10] were synthesized according to the proce-
dure reported.
(Squalane supported on Chromosorb P-AW 10% 60ꢀ
80 mesh), FFAP column (‘Free Fatty Acids Phase’
supported on Chromosorb G AW-DMCS 5%), POR-
/
APAK (Porapak Q polymer, 100ꢀ
GCꢀMS analyses were carried out using a Shimadzu
GCꢀMS-QP5050A mass instrument with a capillary
column SPTM-1 (30 m length, 0.25 mm diameter, 0.1 mm
/120 mesh).
/
/
The other substrates and products were employed as
purchased without further purification.

206
P. Frediani et al. / Journal of Organometallic Chemistry 667 (2003) 197ꢀ208
/
4.2. Syntheses of the biisoq (1)
4.3.2. [Ru(biisoq)3](CH3COO)2 (2a)
In a 50 ml round bottom flask equipped with a reflux
condenser [Ru2(CO)4(CH3COO)2]n (108.4 mg, 0.50
mmol of ruthenium), 1 (138 mg, 0.53 mmol) and acetic
acid (15 ml) were introduced and kept 4 days at the
reflux temperature avoiding the exposure to sun light.
The solvent was distilled under reduced pressure and the
residue 2a was purified using a preparative thin layer
chromatography (Al2O3 eluted with methanol): the
second fraction (purple) was recovered. The complex
4.2.1. Lithium diisopropylamide (LDA)
Butyllithium 1.6 M solution in hexanes (14 ml, 22.4
mmol) was introduced under nitrogen in a 100 ml
Schlenk tube and concentrated by bubbling nitrogen
up to 1/3 of the starting volume. The solution was
cooled to ꢂ78 8C, with vigorous stirring under nitrogen,
/
THF (15 ml) and than diisopropylamine (3 ml, 21.4
mmol) were added. The stirred solution was heated to
0 8C and kept at this temperature for 10 min. The LDA
solution was immediately employed.
(yield 10%) was crystallized from a methylene chlorideꢀ
/
heptane solution.
4.3.3. [Ru(biisoq)3](PF6)2 (2b)
In a sample tube 2a (60 mg, 0.06 mmol) was dissolved
in 10 ml of deionized water, than NH4PF6 (20 mg, 0.12
mmol) was introduced. The complex was found to
crystallize readily (yield 96%) as very small purple
4.2.2. 1,1?-Biisoquinoline
Isoquinoline (5 ml, 42.5 mmol), HMPA (7.4 ml, 42.3
mmol) and diethyl ether (75 ml) were introduced under
nitrogen in a 250 ml round bottom flask; the solution
needles that were centrifuged, washed with water (3ꢄ
/
was cooled to ꢂ
LDA solution previously prepared was slowly added in
10 min. The solution was stirred for 1 h at ꢂ78 8C and 1
/
78 8C and under vigorous stirring, the
2 ml) and dried under vacuum.
/
4.3.4. Ru2(biisoq)2(Cl)4×
/
NEt3 (3a)
h at 25 8C under nitrogen then another 12 h in the
presence of air. The solution became purple red after the
first 2 h, and orange at the end. Twenty ml of water were
added to the solution under stirring, than the aqueous
layer was separated. The organic layer was washed three
times with water (50 ml each) and the washing water
combined with the initial water layer was extracted with
diethyl ether three times (50 ml each). All organic layers
were combined and dried with sodium sulfate. The
solvent was distilled under reduced pressure and the oily
residue purified from HMPA through a basic alumi-
nium oxide column (2 cm length) eluted with a
Biisoq 1 (205 mg, 0.8 mmol), [Ru(Cl)2(h4-1,5-COD)]n
(0.73 mmol of Ru), triethylamine (1.8 ml, 12.8 mmol)
and 25 ml of toluene were introduced in an autoclave
under nitrogen and kept for 3 h at 140 8C under stirring.
The solvent was distilled under vacuum, the solid
residue dissolved in methylene chloride and filtered
through celite 545. The complex (286.5 mg, yield 82%)
was crystallized as very small green needles by addition
of diethyl ether.
4.3.5. [Ru(h6-p-cymene)(Cl)(biisoq)](Cl)×
(4a)
/
0.5Et2O
methanolꢀtoluene (5/95) mixture. The fractions contain-
/
In a 100 ml round bottom flask equipped with a reflux
condenser, biisoq (347 mg, 1.36 mmol), [Ru(h6-p-
cymene)(Cl)2]2 (411 mg, 1.34 mmol of Ru), ethanol (35
ml) and benzene (5 ml) were introduced under nitrogen.
The solution was heated and stirred at 55 8C for 40 min.
The solvent was distilled under reduced pressure and the
red oily residue purified with a flash chromatography
using a neutral aluminium oxide as support and
methanol as eluent. The product was collected in the
first fraction, the solvent distilled under reduced pres-
sure and the oily residue dissolved in chloroform. The
solution was slowly dropped in diethyl ether under
vigorously stirring: the free ligand remains in ether and
very small light orange needles were collected. The
complex (766 mg, yield 95.6%) was washed with ether
and dried under high vacuum on potassium hydroxide.
ing the product were combined and the solvent distilled
under reduced pressure. The oily residue was purified by
flash chromatography using a silica gel column (20 cm
length, eluted with a MTBEꢀPE 4:1 mixture). The first
/
fraction contains isoquinoline and the second biisoq.
The solvent of the biisoq fraction was distilled under
reduced pressure and the residue was collected as yellow
crystals (1.89 g, yield 34.4%).
4.3. Syntheses of the ruthenium complexes
4.3.1. [Ru2(biisoq)2(CO)4(CH3COO)](CH3COO)
(1)
In a 50 ml round bottom flask equipped with a reflux
condenser [Ru2(CO)4(CH3COO)2]n (154.5 mg, 0.715
mmol of ruthenium), biisoq (182.3 mg, 0.712 mmol)
and ethanol (30 ml) were introduced and kept for 3 h at
the reflux temperature. The yellow solid was filtered,
4.3.6. [Ru(h6-p-cymene)(Cl)(biisoq)][B(C6H5)4]
(4b)
In a 250 ml round bottom flask equipped with a reflux
condenser 4a (678.7 mg, 1.13 mmol), NaB(C6H5)4 (621
mg, 1.82 mmol) and ethanol (90 ml) were introduced
washed with ethanol (3ꢄ/5 ml) and dried under vacuum
(191 mg, 56.5% yield).

P. Frediani et al. / Journal of Organometallic Chemistry 667 (2003) 197ꢀ
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207
under nitrogen and the mixture heated and stirred for 3
h at the reflux temperature. The orange solid product
was filtered, washed with cold methanol and dried under
vacuum (716.4 mg, yield 75%).
trans-4-Phenyl-3-buten-2-one: hydrogenation pro-
ducts were analyzed using a FFAP column kept at
50 8C for 2 min, then heated a rate of 10 8C minꢂ1 up to
180 8C and kept at this temperature for 20 min.
Styrene: hydrogenation product was analyzed using a
FFAP column kept at 80 8C for 40 min.
Phenylacetylene: hydrogenation products were ana-
lyzed using a FFAP column kept at 80 8C for 40 min,
then heated at a rate of 10 8C minꢂ1 up to 200 8C and
kept at this temperature for 30 min.
4.4. Crystal structure determination of [Ru(h6-p-
cymene)(Cl)(biisoq)][B(C6H5)4] (4b)
The crystal data and experimental details are given in
Tables 6 and 7. X-ray data were collected on a Bruker
Smart 1000 area detector diffractometer using a graphite
Acetone: hydrogenation product was analyzed using a
PORAPAK column kept at 100 8C for 10 min, then
heated at a rate of 2 8C minꢂ1 up to 150 8C and kept at
this temperature for 10 min.
monochromated MoꢀKa radiation. Absorption was
/
applied using SADABS, Bruker software. The structure
was solved by direct methods and different Fourier
techniques. Full-matrix least-squares refinement on F2
was used with anisotropic thermal parameters for all
non-hydrogen atoms with exception for the methyl C9ƒ
atom and some of the carbon atoms of B(C6H5)4ꢂ
counteranion, which had a very large thermal motion,
and therefore, refined isotropically. The hydrogen atoms
of the cation complex were refined isotropically in their
calculated riding position, the hydrogen atoms of
B(C6H5)4ꢂ were ignored. Calculations were carried out
using SHELXS97 [15] and SHELXL97 [16] programs.
Selected interatomic distances, angles and torsion angles
are given in Table 7. Final positional parameters are
available as Supporting Information.
5. Supplementary material
Crystallographic data (crystal data and structure
refinement, atomic coordinates and equivalent isotropic
displacement parameters, bond lengths and angles,
anisotropic displacement parameters, hydrogen coordi-
nates and isotropic displacement parameters) for 4b
have been deposited with the Cambridge Crystallo-
graphic Data Centre, CCDC no. 192845. Copies of
this information may be obtained free of charge from
The Director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (Fax: ꢁ44-1223-336033; e-mail: deposit@
ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
/
4.5. Hydrogenation reactions and analysis of the products
The reactions were carried out in a 150 ml stainless
steel rocking autoclave. The air was evacuated prior to
the introduction of the solution containing solvent,
catalyst and substrate. Hydrogen was then added up
to 100 atm. The autoclave was heated in an oil bath
Acknowledgements
We wish to thank the University of Florence and the
‘‘Ministero dell’Istruzione, dell’Universita` e della Ricer-
ca (M.I.U.R.), Programmi di Ricerca di Notevole
thermostated at the prefixed temperature (91 8C) and
/
rocked for the prefixed time. After rapid cooling at
room temperature, the hydrogen was vented and the
solution collected and analyzed by gas chromatography.
Interesse Nazionale, Cofinanziamento M.I.U.R. 2000ꢀ
/
2001’’ for financial support. We would like to thank
Brunella Innocenti of the University of Florence for the
elemental analysis; Mara Camaiti of the C.N.R.-
C.S.C.O.A. of Florence for the help given in the
registration of the IR spectrum in the ‘far IR’ region;
Gloriano Moneti of the University of Florence for the
ESI/time-of-flight mass spectra; Fabrizio Zanobini of
the C.N.R.-I.C.C.O.M. of Florence and Elisabetta Berti
for the help given in the crystallization technique.
A
GC capillary column Al2O3ꢀNa2SO4 PLOT
/
(Chrompack, length: 50 m, diameter: 0.45 mm) was
used to analyze hexane and the residual hexenes: the
oven was kept at 130 8C for 25 min, then heated at a rate
of 30 8C minꢂ1 up to 200 8C and kept at this
temperature for 50 min; the sample before analysis
was added with THF to unify the two layers present at
the end of the reaction.
Cyclohexene: hydrogenation products were analyzed
using a SQ column: the oven was kept at 40 8C for 20
min, then heated a rate of 10 8C minꢂ1 up to 130 8C and
kept at this temperature for 20 min; the sample before
analysis was added with THF to unify the two layer
present at the end of the reaction.
trans-2-Methylbut-2-enoic acid: hydrogenation pro-
ducts were analyzed using a FFAP column kept at
150 8C for 60 min.
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