Supported organometallic complexes Part 34: Synthesis and structures of an array of diamine(ether-phosphine)ruthenium(II) complexes and their application in the catalytic hydrogenation of trans-4-phenyl-3-butene-2-one

Article abstract of DOI:10.1016/S0020-1693(02)01535-9

The novel diamine-bis(ether-phosphine)ruthenium(II) complexes Cl ₂Ru(η¹-Ph₂PCH₂-CH ₂OCH₃)₂(diamine)₂(3L ₁-3L₁₁) have been obtained by reaction of

Full text of DOI:10.1016/S0020-1693(02)01535-9

Inorganica Chimica Acta 350 (2003) 49Á56
/
www.elsevier.com/locate/ica
Supported organometallic complexes Part 34: synthesis and structures
of an array of diamine(etherÁphosphine)ruthenium(II) complexes and
their application in the catalytic hydrogenation of
/
trans-4-phenyl-3-butene-2-oneꢀ
Ekkehard Lindner *, Ismail Warad, Klaus Eichele, Hermann A. Mayer
Institut fur Anorganische Chemie der Universitat Tubingen, Auf der Morgenstelle 18, D-72076 Tubingen, Germany
¨ ¨ ¨ ¨
Received 18 March 2002; accepted 24 June 2002
Dedicated to Professor Pierre Braunstein.
Abstract
The novel diamineÁ
been obtained by reaction of equimolar amounts of Cl2Ru(PS
/
bis(etherÁ
/
phosphine)ruthenium(II) complexes Cl2Ru(h1-Ph2PCH2Ã
O)2 (2) with the respective diamines L1Á
/
CH2OCH3)2(diamine)2(3L1Á
/
3L11) have
/
/L11 in good yields. X-ray
structural investigations of 3L2 and 3L8 show monoclinic unit cells with the space group P21/c. The octahedrally coordinated
ruthenium atoms have each two trans-chlorides and cis-phosphines which is in agreement with NMR studies in solution. With the
exception of 3L4 all mentioned ruthenium complexes are highly catalytically active in the hydrogenation of the a,b-unsaturated
ketone trans-4-phenyl-3-butene-2-one. In most cases the conversions and selectivities toward the formation of the unsaturated
alcohol trans-4-phenyl-3-butene-2-ol were 100% with high turnover frequencies under mild conditions.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Ruthenium(II) complexes; Crystal structures; EtherÁphosphines; Hemilabile ligands; Catalytic hydrogenation
/
1. Introduction
synthetic route to a set of neutral and cationic diamineÁ
/
bis(etherÁphosphine)ruthenium(II) complexes and their
/
Combinatorial chemistry and parallel syntheses be-
come increasingly important in several areas of chem-
istry [2,3]. Recently this technique has been transferred
to heterogeneous and homogeneous catalysis [1,2,4]. A
prospective objective of our group is the combination of
parallel syntheses and interphase chemistry and its
transfer to catalysis. Interphase catalysts demonstrate
a great importance since they are able to combine the
advantages of homogeneous and heterogeneous cataly-
sis with a marked reduction of notorious drawbacks like
leaching and reduced catalytic activity of the reactive
complete structural characterization. Compounds of
this type can easily be supported in polysiloxane
matrices and are potential candidates for the application
of parallel methods. Due to the hemilabile character the
oxygen donor is regarded as an intramolecular solvent
impeding decomposition of the complex by protection
of vacant coordination sites [12Á
rutheniumÃoxygen bonds in bis(chelate)ruthenium(II)
complexes of the type Cl2Ru(PS O)2 are easily cleaved
/17]. The weak
/
/
during the reaction with diamines. Diaminediphos-
phineruthenium(II) complexes with classical phosphine
ligands were already successfully employed in the
catalytic hydrogenation of unsaturated ketones with
centers [5Á11]. In a recent paper [12], we reported on a
/
high diastereo- and enantioselectivity [18Á
/
25]. By the
ꢀ For Part 33 see Ref. [1].
* Corresponding author. Tel.: ꢀ
29 5306.
E-mail address: ekkehard.lindner@uni-tuebingegen.de (E. Lindner).
employment of etherÁphosphines the introduction of
/
/
49-7071-29 72039; fax: ꢀ49-7071-
/
diamines is kinetically controlled and the formation of
by-products is avoided [12].
0020-1693/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0020-1693(02)01535-9

50
E. Lindner et al. / Inorganica Chimica Acta 350 (2003) 49Á56
/
Here we wish to report on the preparation and
characterization of variety of novel diamineÁ
bis(etherÁphosphine)ruthenium(II) complexes using ali-
a
/
/
phatic diamines with different substituents in the back-
bone as well as chiral cycloaliphatic and aromatic, and
substituted aromatic diamines. Complexes of this type
proved to be efficient catalysts in the hydrogenation of a
conjugated ketone. In a future step these complexes will
be simultaneously tested in a specially designed parallel
autoclave.
2. Experimental
2.1. General remarks, materials, and instrumentations
All reactions were carried out in an inert atmosphere
(argon) by using standard high vacuum and Schlenk-line
techniques unless otherwise noted. Prior to use CH2Cl2,
n-hexane, and Et2O were distilled from CaH2, LiAlH4,
and from sodium/benzophenone, respectively.
The etherÁphosphine ligand Ph2PCH2CH2OCH3 was
/
prepared according to literature methods [26]. The
trans-4-phenyl-3-butene-2-one and the diamines were
purchased from Acros, Fluka, and Merck and had to be
purified. Ph3P and RuCl3×
/
3H2O were available from
Merck and Chempur, respectively, and were used with-
out further purification. Elemental analyses were carried
out on an Elementar Vario EL analyzer. High-resolu-
tion 1H, 13C{1H}, DEPT 135, and 31P{1H} NMR
spectra were recorded on a Bruker DRX 250 spectro-
Scheme 1.
1
meter at 298 K. Frequencies are as follows: H NMR
250.12 MHz, 13C{1H} NMR 62.9 MHz, and 31P{1H}
NMR 101.25 MHz. Chemical shifts in the 1H and
13C{1H} NMR spectra were measured relative to
partially deuterated solvent peaks which are reported
relative to TMS. 31P chemical shifts were measured
removal of any turbidity by filtration (P4), the volume
of the solution was concentrated to about 5 ml under
reduced pressure. Addition of 40 ml of diethyl ether
caused the precipitation of a solid which was filtered
(P4), then dissolved again in 40 ml of dichloromethane
and concentrated under vacuum to a volume of 5 ml.
Addition of 80 ml of n-hexane caused the precipitation
of a solid which was filtered (P4) and washed three times
with 25 ml of n-hexane each and dried under vacuum.
relative to 85% H3PO4 (dꢁ0). IR data were obtained on
/
a Bruker IFS 48 FT IR spectrometer. Mass spectra: EI
MS; Finnigan TSQ70 (200 8C). FAB MS; Finnigan 711
A (8 kV), modified by AMD and reported as mass/
charge (m/z). The analyses of the hydrogenation experi-
ments were performed on a GC 6000 Vega Gas 2 (Carlo
Erba Instrument) with a FID and capillary column PS
255 [10 m, carrier gas, He (40 kPa), integrator 3390 A
(Hewlett Packard)].
2.2.1. 3L1
Complex 2 (300 mg, 0.454 mmol) was treated with L1
(0.05 ml, 0.50 mmol) to give 3L1. Yield 299 mg (88%) of
1
a yellow powder, m.p 227 8C, dec. 250 8C. H NMR
(CDCl3): d (ppm) 1.1 (s, 6H, CH3), 2.5 (m, 4H, PCH2),
2.2. General procedure for the preparation of the
3L11 (see Scheme 1)
complexes 3L1Á
/
2.8 (m, 4H, CH2O), 2.8Á
/
3.0 (m, 6H, NH2CH2), 2.94,
7.60 (m, 20H, C6H5). 31P{1H}
2.96 (s, 6H, OCH3), 7.17Á
/
2
The corresponding diamine ligand (10% excess of L1Á
/
NMR (CDCl3): d (ppm) 38.3, 39.0 (AB pattern, JPP
ꢁ
/
L11) was dissolved in 25 ml of dichloromethane and the
solution was added dropwise to a stirred solution of 2 in
25 ml of dichloromethane. After the reaction mixture
was stirred approximately for 45 min at room tempera-
ture (r.t.), the color changed from red to yellow. After
36.29 Hz). 13C{1H} NMR (CDCl3): d (ppm) 25.5 (m,
PCH2), 29.1 (s, CH3), 54.7 (s, NCH2), 55.7 (s,
NC(CH3)2), 58.2 (s, OCH3), 69.22, 69.29 (2s, CH2O),
128.3 (m 27a, Nꢁ
/
14.14 Hz, m-C H ), 129.3 (s, p-
¯
6 5
C6H5), 133.1 (m 27b, Nꢁ
/
8.08 Hz, o-C6H5), 134.17,

E. Lindner et al. / Inorganica Chimica Acta 350 (2003) 49Á
/
56
51
134.67 (2m 27c, Nꢁ
/
8.08 Hz, i-C6H5). FAB MS: (m/z)
2.2.5. 3L5
Complex 2 (300 mg, 0.454 mmol) was treated with L5
(0.105 g, 0.50 mmol) to give 3L5. Yield 356 mg (90%) of
748.2 (Mꢀ). Anal. Calc. for C34H46Cl2N2O2P2Ru: C,
54.55; H, 6.19; Cl, 9.47; N, 3.74. Found: C, 54.38; H,
6.47; Cl, 9.35; N, 3.64%.
1
a yellow powder, m.p. 232 8C, dec. 239 8C. H NMR
(CDCl3): d (ppm) 2.2Á/4.2 (m, 14H, PCH2, OCH2,
NH2CH), 2.93 (s, 6H, OCH3), 6.7Á
/
7.7 (m, 30H,
C6H5). 31P{1H} NMR (CDCl3): d (ppm) 39.0 (s).
13C{1H} NMR (CDCl3): d (ppm) 25.8 (m, PCH2),
58.2 (s, OCH3), 63.9 (s, NCH), 69.3 (s, OCH2), 127.2
2.2.2. 3L2 (with trans-L2)
Complex 2 (300 mg, 0.454 mmol) was treated with L2
(0.061 ml, 0.50 mmol) to give 3L2. Yield 337 mg (96%)
of a yellowÁ
/
brown powder, m.p. 221 8C, dec. 224 8C. 1H
(s, o-C6H5), 128.2 (s, p-C6H5), 128.3 (m 27a, Nꢁ
Hz, m-C6H5), 128.9 (s, m-C6H5), 129.3, 129.5 (2s, p-
C6H5), 132.6, 133.3 (2m 27b, Nꢁ8.08 Hz, o-C6H5)
/8.08
NMR (CDCl3): d (ppm) 1.0Á/3.4 (m, 22H, CH2CH2,
PCH2, NCH, NH2, OCH2), 2.9 (s, 6H, OCH3), 7.2Á
/
7.7
/
(m, 20H, C6H5). 31P{1H} NMR (CDCl3): d (ppm) 38.8
(s). 13C{1H} NMR (CDCl3): d (ppm) 24.9 (s, CH2), 25.4
(m, PCH2), 36.2 (s, CH2), 57.7 (s, NCH), 58.2 (s, OCH3),
134.4 (2m, i-C6H5), 140.2 (s, i-C6H5). FAB MS: (m/z)
872.2 (Mꢀ). Anal. Calc. for C44H50Cl2N2O2P2Ru: C,
60.55; H, 5.77; Cl, 8.12; N, 3.21. Found: C, 60.28, H,
5.48; Cl, 7.98; N, 3.03%.
69.3 (s, CH2O), 128.3 (m 27a, Nꢁ/8.08 Hz, m-C6H5),
129.2, 129.4 (2s, p-C6H5), 132.6, 133.4 (2 m 27b, Nꢁ
/
8.08, o-C6H5), 134.4, 134.7 (2 m 27c, Nꢁ69.72, i-
/
C6H5). FAB MS: (m/z) 774.2 (Mꢀ). Anal. Calc. for
C36H48Cl2N2O2P2Ru: C, 55.55; H, 6.19; Cl, 9.47; N,
3.74. Found: C, 55.33; H, 6.43; Cl, 9.35; N, 3.42%.
2.2.6. 3L6
Complex 2 (300 mg, 0.454 mmol) was treated with L6
(0.105 g, 0.50 mmol) to give 3L6. Yield 348 mg (88%) of
1
a yellow powder, m.p. 220 8C, dec. 224 8C. H NMR
(CDCl3): d (ppm) 2.2Á
/
4.2 (m, 14H, PCH2, OCH2,
2.2.3. 3L3 (mixture of cis/trans-L3)
Complex 2 (300 mg, 0.454 mmol) was treated with L3
(0.060 ml, 0.50 mmol) to give 3L3. Yield 337 mg (96%)
NH2CH), 2.93 (s, 6H, OCH3), 6.7Á
/
7.7 (m, 30H,
C6H5). 31P{1H} NMR (CDCl3): d (ppm) 39.0 (s).
13C{1H} NMR (CDCl3): d (ppm) 24.5 (m, PCH2),
56.8 (s, OCH3), 62.5 (s, NCH), 67.9 (s, CH2O), 125.8
of a yellowÁ
/
brown powder, m.p. 218 8C, dec. 221 8C. 1H
NMR (CDCl3): d (ppm) 1.0Á/3.4 (m, 22H, CH2CH2,
(s, o-C6H5), 126.8 (s, p-C6H5), 126.9 (m 27a, Nꢁ
Hz, m-C6H5), 127.6 (s, m-C6H5), 127.9, 128.1 (2s, p-
C6H5), 131.1, 131.9 (2m 27b, Nꢁ8.08 Hz, o-C6H5),
133.2 (2m, i-C6H5), 138.8 (s, i-C6H5). FAB MS: (m/z)
872.2 (Mꢀ). Anal. Calc. for C44H50Cl2N2O2P2Ru: C,
60.55; H, 5.77; Cl, 8.12; N, 3.21. Found: C, 60.31, H,
5.50; Cl, 7.97; N, 2.90%.
/8.79
PCH2, NCH, NH2, OCH2). 2.9 (s, 6H, OCH3), 7.1Á
/
7.8
(m, 20H, C6H5). 31P{1H} NMR (CDCl3): d (ppm) 38.6,
38.9 (2s). 13C{1H} NMR (CDCl3): d (ppm) 22.2, 24.9
(2s, CH2), 25.4 (m, PCH2), 29.0, 36.2 (2s, CH2), 54.1 (s,
NCH), 57.7 (s, NCH), 58.2 (s, OCH3), 69.3 (s, CH2O),
/
128.3 (m 27a, Nꢁ
(3s, p-C6H5), 132.6, 132.9, 133.3 (3m 27b, Nꢁ
/
8.08 Hz, m-C6H5), 129.2, 129.3, 129.4
8.08, o-
69.72, i-C6H5). FAB
/
C6H5), 134.4, 134.7 (2m 27c, Nꢁ
/
MS: (m/z) 774.2 (Mꢀ). Anal. Calc. for C36H48Cl2N2O2-
P2Ru: C, 55.55; H, 6.19; Cl, 9.47; N, 3.74. Found: C,
55.45; H, 6.33; Cl, 9.28; N, 3.56%.
2.2.7. 3L7
See Ref. [12].
2.2.4. 3L4
2.2.8. 3L8
Complex 2 (300 mg, 0.454 mmol) was treated with L8
(0.059 ml, 0.49 mmol) to give 3L8. Yield 310 mg (90%)
of a yellow powder, m.p. 206 8C, dec. 213 8C. H NMR
(CD2Cl2): d (ppm) 0.8 (s, 6H, C(CH3)2), 2.2 (m, 4H,
NCH2), 2.6 (m, 2H, PCH2), 2.8 (br, s, 10H, NH2,
Complex 2 (300 mg, 0.454 mmol) was treated with L4
(0.061 g, 0.50 mmol) to give 3L4. Yield 337 mg (95%) of
a light orange powder, m.p. 220 8C, dec. 224 8C. 1H
NMR (CDCl3): d (ppm) 2.1 (s, 3H, CH3), 2.4 (m, 4H,
PCH2), 2.9 (s, 6H, OCH3,) 3.0 (m, 4H, OCH2), 4.4 (br,
1
4H, NH2), 6.5Á
/
7.8 (m, 23H, C6H5, C6H3). 31P{1H}
OCH3), 2.9 (s, 4H, CH2O), 7.2Á7.7 (m, 20H, C6H5).
/
NMR (CDCl3): d (ppm) 40.6 (s). 13C{1H} NMR
(CDCl3): d (ppm) 21.0 (s, CH3), 25.4 (m, PCH2), 58.2
(s, OCH3), 69.2 (s, CH2O), 127.5, 128.2, 128.3 (3s,
31P{1H} NMR (CD2Cl2): d (ppm) 40.69 (s). 13C{1H}
NMR (CD2Cl2): d (ppm) 25.4 (s, C(CH3)2), 26.2 (m,
PCH2), 34.5 (s, C(CH3)2), 50.0 (s, CH2N), 58.1 (s,
C6H3), 128.5 (m 27a, Nꢁ
C6H5), 133.0 (m 27b, Nꢁ
/
8.76 Hz, m-C6H5), 129.6 (s, p-
8.76 Hz, o-C6H5), 134.4 (m
36.38 Hz, i-C6H5), 137.5, 139.9 (s, br, C6H3).
OCH3), 69.5 (s, CH2O), 128.2 (m 27a, Nꢁ
C6H5), 129.2 (s, p-C6H5), 132.7 (m 27c, Nꢁ
/
8.77 Hz, m-
33.68 Hz, i-
7.42 Hz, o-C6H5). FAB MS:
/
/
27c, Nꢁ
/
C6H5) 133.2 (m 27b, Nꢁ
/
FAB MS: (m/z) 872.2 (Mꢀ). Anal. Calc. for
C37H44Cl2N2O2P2Ru: C, 56.78; H, 5.67; Cl, 9.06; N,
3.58. Found: C, 56.39; H, 6.00; Cl, 9.16; N, 3.79%.
(m/z) 734.2 (Mꢀ). Anal. Calc. for C35H48Cl2N2O2P2Ru:
C, 55.12; H, 6.34; Cl, 9.30; N, 3.67. Found: C, 54.94; H,
5.92; Cl, 9.20; N, 3.59%.

52
E. Lindner et al. / Inorganica Chimica Acta 350 (2003) 49Á56
/
2.2.9. 3L9
Complex 2 (300 mg, 0.454 mmol) was treated with L9
(0.059 ml, 0.49 mmol) to give 3L9. Yield 308 mg (88%)
during the evacuation process to remove oxygen and
water. Subsequently the Schlenk tube was filled with
argon and 20 ml of 2-propanol was added. The mixture
1
of a yellow powder, m.p. 197 8C, dec. 199 8C. H NMR
was vigorously stirred, degassed by two freezeÁ
/thaw
3
(CDCl3): d (ppm) 0.9 (t, JHH
ꢁ
/
7.38 Hz, CH3), 1.1Á
/2.6
cycles, and then sonicated for 20Á40 min (this is
/
(m, 19H, CH2CHCH2CH2, NH2, PCH2, CH2O), 2.6 (s,
7.7 (m, 20H, C6H5). 31P{1H} NMR
important to complete the dissolving of the catalyst
and cocatalyst). A solution of trans-4-phenyl-3-butene-
2-one (26 mmol) in 60 ml of 2-propanol was subjected to
6H, OCH3), 7.2Á
/
2
(CDCl3): d (ppm) 40.2, 40.7 (AB pattern, JPP
ꢁ35.35
/
Hz). 13C{1H} NMR (CDCl3): d (ppm) 9.2 (s, CH3), 25.5
(m, PCH2), 32.8 (s, CH2CH3), 34.3 (s, CH2CH2N), 39.6
(s, CH2N), 51.3 (s, CHN), 57.6 (s, OCH3), 68.9 (s,
a freezeÁthaw cycle in a different 150 ml Schlenk tube
/
and was added to the catalyst solution. Finally the
reaction mixture was transferred to a pressure Schlenk
CH2O), 127.8Á
/
128.2 (m, m-C6H5), 129.5Á/129.6 (m, p-
tube which was pressurized with dihydrogen of 1Á4 bar.
/
C6H5), 132.5 (m, i-C6H5) 133.2Á
/
133.7 (m, o-C6H5).
The reaction mixture was vigorously stirred at 35 8C for
1 h. During the hydrogenation process samples were
taken from the reaction mixture to control the conver-
sion and turnover frequency. The samples were inserted
by a special glass syringe into a gas chromatograph and
the kind of the reaction products was compared with
authentic samples.
FAB MS: (m/z) 762.2 (Mꢀ). Anal. Calc. for
C35H48Cl2N2O2P2Ru: C, 55.12; H, 6.34; Cl, 9.30; N,
3.67. Found: C, 54.89. H, 5.96; Cl, 9.29; N, 3.69%.
2.2.10. 3L10
Complex 2 (300 mg, 0.454 mmol) was treated with L10
(0.141 g, 0.50 mmol) to give 3L10. Yield 368 mg (86%) of
1
a light brown powder, m.p. 210 8C, dec. 215.1 8C. H
NMR (CDCl3): d (ppm) 1.7 (m, 4H, PH2), 2.9 (s, 6H,
2.4. X-ray structural analyses for complexes 3L2 and 3L8
OCH3), 3.0 (m, 4H, CH2O), 4.3 (d, 2JHH
ꢁ/8.55 Hz, 2H,
Crystals of 3L2 and 3L8 were grown by slow diffusion
of diethyl ether into a solution of the complex in
dichloromethane. Data were collected at 173(2) K on a
Siemens P4 diffractometer operating in the v scan
2
NH2), 5.0 (d, JHH
ꢁ
/
8.55 Hz, 2H, NH2), 64Á
/7.9 (m,
32H, C6H5, C20H12). 31P{1H} NMR (CDCl3): d (ppm)
43.4 (s). 13C{1H} NMR (CDCl3): d (ppm) 24.6 (m,
PCH2), 58.2 (s, OCH3), 69.4 (s, CH2O), 128.3Á
/
129.2 (m,
mode, using graphite monochromated Mo Ka radiation
˚
0.71073 A). Details of crystal data, data collection,
m-C6H5), 129.7, 130.1 (2s, p-C6H5), 132.4, 134.3 (2m, o-
C6H5) 133.3 (m, i-C6H5), 119.9, 123.4, 124.8, 125.8,
126.7, 131.3, 133.8, 134.0, 134.1, 140.6 (10s, C20H12).
FAB MS: (m/z) 774.2 (Mꢀ). Anal. Calc. for
C36H48Cl2N2O2P2Ru: C, 63.56; H, 5.33; Cl, 7.50; N,
2.96. Found: C, 63.17; H, 5.6; Cl, 7.43; N, 2.82%.
(lꢁ
/
and structure refinement are given in Table 1. The
structures were solved by direct methods using the
Bruker SHELXS-97 program [28a] and refined by full-
matrix least-squares on F2 using the Bruker SHELXL-97
program [28b]. Non-hydrogen atoms were refined with
anisotropic displacement parameters. Hydrogen atoms
were constrained to idealized positions using a riding
model (with free rotation for methyl groups). The
difference electron density map and thermal ellipsoids
of 3L2 indicated a disorder of the cyclohexane ring of
the diamine; this disorder was treated by introducing
split positions corresponding to the opposite enantio-
meric form of the ligand; the occupation number was
allowed to refine, giving a ratio of 0.708:0.292.
2.2.11. 3L11
Complex 2 (300 mg, 0.454 mmol) was treated with L11
(0.043 ml, 0.494 mmol) to give 3L11. Yield 152.7 mg
(45%) of a yellow powder, m.p. 132 8C, dec. 141 8C. H
NMR (CDCl3): d (ppm) 1.6 (br, 8H, 2CH2CH2), 2.3 (m,
1
4H, PCH2), 2.62Á3.1 (br, 8H, NH2, CH2O), 2.9 (s, 6H,
/
OCH3), 7.1Á
7.6 (m, 20H, C6H5). 31P{1H} NMR
/
(CDCl3): d (ppm) 40.2 (s). 13C{1H} NMR (CDCl3): d
(ppm) 27.7 (m, PCH2), 40.3 (s, CH2), 56.6 (s, NCH2),
57.5 (s, OCH3), 68.5 (s, CH2O), 128.3 (m 27a, Nꢁ
Hz, m-C6H5), 129.4 (s, p-C6H5), 133.6 (m 27c, Nꢁ33.68
Hz, i-C6H5) 133.7 (m 27b, Nꢁ7.42 Hz, o-C6H5). FAB
MS: (m/z) 747.87 (Mꢀ). Anal.
Calc. for
/
8.78
/
3. Results and discussion
/
3.1. Synthesis of the diamineÁ
/
bis(etherÁ
/
C34H46Cl2N2O2P2Ru: C, 54.55; H, 6.19; Cl, 9.47; N,
3.74. Found: C, 54.28; H, 6.40; Cl, 9.34, N, 3.73%.
phosphine)ruthenium(II) complexes (3L1Á3L11)
/
If the bis(etherÁ
[12,14] is treated with the different diamines L1Á
dichloromethane the yellow, somewhat air-sensitive
mixed diamineÁbis(etherÁphosphine)ruthenium(II)
complexes 3L1Á3L11 are formed in good to excellent
/
phosphine)ruthenium(II) complex 2
2.3. General procedure for the catalytic studies
/L11 in
The respective diamineÁ
/
bis(etherÁ/phosphine)ruthe-
/
/
nium(II) complex (0.026 mmol) was placed in a 150 ml
Schlenk tube and solid KOH (0.26 mmol) was added as
a cocatalyst. The solid mixture was stirred and warmed
/
yields (Scheme 1). They are soluble in chlorinated
organic solvents and insoluble in ethers and aliphatic

E. Lindner et al. / Inorganica Chimica Acta 350 (2003) 49Á
/
56
53
Table 1
Crystal data and structure refinement for 3L2 and 3L8
assignment was supported by two-dimensional H,H
COSY experiments which establish the connectivity
between NH2 and CH2 functions in the diamine ligand,
and between CH2O and CH2P groups in the phosphine
fragment. The integration of the H resonances confirm
that the phosphine to diamine ratios are in agreement
3L2
3L8
1
Crystal habit
Crystal color
block
orange
plate
orange
Crystal size (mm)
Empirical formula
Formula weight
0.6ꢃ
/
0.6ꢃ
/
0.6
0.5ꢃ
/
0.3ꢃ
/0.08
with the compositions of 3L1Á
chemical shifts of the singlets due to the protons of the
methoxy groups are consistent with the h1-PÂ
O unit
[12]. In the 31P{1H} NMR spectra of 3L2, 3L3, 3L5Á
3L8,
/3L11. Furthermore, the
C36H48Cl2N2O2P2Ru C35H48Cl2N2O2P2Ru
762.66
774.67
˚
a (A)
/
15.645(2)
9.5424(15)
24.828(7)
90
11.4223(14)
28.394(4)
12.2829(13)
90
˚
b (A)
/
˚
c (A)
3L10, and 3L11, the singlets indicate that the phosphine
groups are chemically equivalent in solution which is
a (8)
b (8)
g (8)
92.640(15)
90
117.654(11)
90
compatible with the C2v symmetry of the RuCl2(etherÁ
/
phosphine)2diamine complexes. While in the cases of
3L1 and 3L9 the asymmetric diamines cause loss of the
C2 axis resulting in a splitting of the 31P resonances into
AB patterns, in 3L4, the asymmetry is too remote to
generate an observable splitting of the 31P{1H} NMR
Crystal system
Space group
Z
monoclinic
P21/c
monoclinic
P21/c
4
18 307/8506
4
9684/8091
Reflections collected/
unique
Rint
0.0319
0.0391
signal. The phosphorus chemical shifts and the 31PÁ31
coupling constants suggest that the etherÁphosphines
are h1-PÃ
O coordinated [12Á17] and are positioned cis
/
P
Limiting indices
ꢂ
/
205
125
325
2.29Á27.50
/
h 5
k 5
l 532
/
1,
ꢂ
/
15
15
155
2.00Á27.51
/
h 5
k 5
l 5
/
14,
36,
14
ꢂ
/
/
/
12,
ꢂ
/
/
/
/
ꢂ/
/
/
ꢂ/
/
/
/
/
u Range for data
collection (8)
Completeness to u (%) 99.8
/
/
to each other. Thus, if a diamine chelate is present, both
chlorines have to be in mutual trans-arrangements. The
13C{1H} NMR spectra also corroborate the structures
given in Scheme 1. Characteristic 13C signals are due to
99.9
0.720
Absorption coefficient
(mmꢂ1
0.688
)
the h1-PÂ
aliphatic and aromatic diamines.
The IR spectra of the complexes 3L1Á
particular show four sets of characteristic absorptions
in the ranges 3386Á3300, 3272Á3205, 3178Á3165, and
280Á
260 cmꢂ1, which can be assigned to NH2, amineÃ
CH, phosphineÃCH and RuCl stretching vibrations,
respectively.
/O binding mode as well as due to the
Absorption correction
Data/restraints/para-
meters
Goodness-of-fit on F2
Final R indices
none
8506/0/464
1.060
none
8091/0/402
/
3L11 in
1.033
0.0240/0.0605
0.0271/0.0619
0.00301(16)
0.0568/0.1885
0.0812/0.2261
0.0001(5)
[I ꢀ2s(I)], R1/wR2
/
/
/
/
R indices (all data),
R1/wR2
Extinction coefficient
/
/
/
Largest difference peak/ 0.353/ꢂ
/0.641
1.770/ꢂ1.708
/
ꢂ3
˚
hole (e A
)
3.3. X-ray structural determination of trans-3L2 and 3L8
hydrocarbons. Their molecular composition was corro-
borated by FAB MS. The yield of the complexes 3L1Á
/
To get a better insight into structural parameters
complexes 3L2 and 3L8 have been selected for X-ray
structural investigations. Crystal structures of 3L2 and
3L8 are shown in Fig. 1, relevant bond distances, angles
and torsion angles are collected in Table 2. Both
compounds crystallize as trans-chloro-cis-phosphine
isomers with approximate C2 symmetry. Ruthenium is
at the center of a mostly regular octahedron, where
Ru(1), P(1), P(2), N(1), and N(2) deviate by less than 0.1
3L11 strongly depends on electronic and steric factors of
the diamine ligands. If one or both hydrogen atoms at
the nitrogen donors are replaced by alkyl or aryl groups
no reaction takes place. This is clearly a steric effect. On
the other hand if in 1,2-phenylenediamine L4 a methyl
group is introduced in the para-position of a NH2
function the yield increases from 59 [12] to 95%, an
observation which is in agreement with an electronic
effect. Electron withdrawing substituents like NO2
groups instead of a methyl function give rise to an
inverse effect, the yield drops to about 13% [25].
˚
A from the equatorial least-squares plane, while the
chlorine ligands are bent away from their axial positions
toward the diamine ligand, forming ClÃ
164.898 (3L2) and 166.728 (3L8). The different sizes of
the diamine chelate rings result in distinctly different NÃ
N angles of 77.858 (3L2) in the five-membered ring
/
RuÃ/Cl angles of
3.2. NMR and IR spectroscopic investigations
/
RuÃ
/
1
In the H NMR spectra of the diamineÁ
/
bis(etherÁ
/
versus 84.548 (3L8) in the six-membered chelate, but the
bite angles of both diamine ligands are obviously
phosphine)ruthenium(II) complexes (3L1Á
/
3L11) charac-
teristic sets of signals are observed, which are attributed
sufficiently small to leave the opposing PÃ
/
RuÃ/P angles
to the phosphine as well as to the diamine ligands. Their
unaffected, 92.398 (3L2) and 91.728 (3L8).

54
E. Lindner et al. / Inorganica Chimica Acta 350 (2003) 49Á56
/
Table 2
˚
Selected bond lengths (A) and bond and torsion angles (8) for 3L2 and
3L8
3L2
3L8
Bond lengths
Ru(1)Ã
Ru(1)Ã
Ru(1)Ã
Ru(1)Ã
Ru(1)Ã
Ru(1)Ã
/
Cl(1)
Cl(2)
P(1)
2.4141(6)
2.4050(5)
2.2737(7)
2.2881(5)
2.1790(13)
2.1797(14)
2.4178(13)
2.4303(14)
2.2807(14)
2.3037(14)
2.170(4)
/
/
/P(2)
/N(1)
/N(2)
2.209(4)
Bond angles
Cl(1)ÃRu(1)Ã
P(1)ÃRu(1)ÃP(2)
N(1)ÃRu(1)Ã
N(1)ÃRu(1)Ã
N(2)ÃRu(1)Ã
N(1)ÃRu(1)Ã
N(2)ÃRu(1)Ã
P(1)ÃRu(1)Ã
P(2)ÃRu(1)Ã
P(1)ÃRu(1)Ã
P(2)ÃRu(1)Ã
/
/
Cl(2)
164.894(15)
92.38(2)
77.76(5)
166.72(5)
91.72(5)
84.54(16)
83.66(14)
82.73(12)
88.16(14)
86.10(12)
99.53(5)
89.47(5)
90.93(5)
98.42(5)
/
/
/
/
N(2)
Cl(1)
Cl(1)
Cl(2)
Cl(2)
/
/
84.74(4)
/
/
83.62(4)
/
/
84.15(4)
/
/
84.04(4)
/
/
Cl(1)
Cl(1)
Cl(2)
Cl(2)
98.985(15)
91.787(15)
92.027(16)
98.090(15)
/
/
/
/
/
/
Torsion angles
N(2)ÃRu(1)ÃN(1)Ã
N(1)ÃRu(1)ÃN(2)Ã
N(1)ÃRu(1)ÃN(2)Ã
Ru(1)ÃN(1)Ã
N(1)ÃC(33)ÃC(34)Ã
N(1)ÃC(33A)ÃC(34A)Ã
Ru(1)ÃN(2)ÃC(35)ÃC(34)
Ru(1)ÃN(2)ÃC(34A)ÃC(33A)
C(33)ÃC(34)ÃC(35)ÃN(2)
/
/
/
C(33,33A)
17.5(2)
12.2(2)
ꢂ
35.2(4)
/
38.8(4)
/
/
/C(35)
/
/
/C(34A)
/
/
C(33,33A)Ã
C(35)
N(2)
/
C(34,34A)
ꢂ
/
43.3(4)
53.1(4)
38.6(4)
62.6(6)
68.5(6)
/
/
/
ꢂ/
/
/
/
/
/
/
ꢂ
/
53.9(6)
/
/
/
ꢂ/
/
/
/
64.1(6)
N(2)Ã
to six-membered cobalt(III) diamine rings that tend to
form more regular chair conformations [29]. The RuÃ
/
C(35) and C(33)Ã
/
C(34)Ã/C(35). This is in contrast
/N
˚
distances of 2.170(4) and 2.209(4) A in 3L8, where
nitrogen is trans to phosphorus, are shorter than those
in a complex of trans-diaminocyclohexane where nitro-
gen is trans to hydrogen atoms, with RuÃ
/
N distances of
˚
2.225(5) and 2.284(5) A [20].
3.4. Catalytic activity of the ruthenium(II) complexes
3L1, 3L2, and 3L4Á3L9 in the selective hydrogenation of
an a,b-unsaturated ketone
/
Fig. 1. ORTEP plots of (a) 3L2 and (b) 3L8 with atom labeling scheme.
Thermal ellipsoids are drawn at the 50% probability level, hydrogens
are omitted for clarity.
To study the catalytic activity of the ruthenium(II)
complexes trans-4-phenyl-3-butene-2-one was selected
as a model substrate, because three different possibilities
of hydrogenation are to be expected (Scheme 2). The
selective hydrogenation of the carbonyl group affords
the corresponding unsaturated alcohol trans-4-phenyl-
3-butene-2-ol (A), which is the most desired product. In
that case the conjugation is interrupted and this effect is
observable in the UV spectrum. Unwanted and hence of
In 3L2, the trans-diaminocyclohexane ligand forms a
typical five-membered chelate with twist conformation,
similar to the complex with 1,2-diaminoethane [12]. This
allows the cyclohexane ring to adopt a chair conforma-
tion. In 3L8, the six-membered diamine chelate also has
a chair structure, but is flattened about the position of
the metal; e.g. the dihedral angle between the planes
minor interest is the hydrogenation of the CÄ
/
C double
N(1)Ã
/
Ru(1)Ã
/
N(2) and N(1)Ã
/
C(33)Ã
/
N(2)Ã
/
C(35) is
bond, leading to the saturated ketone (C). Also not in
the focus of our interest is the hydrogenation of both the
31.098 compared with 56.988 between N(1)Ã
/
C(33)Ã
/

E. Lindner et al. / Inorganica Chimica Acta 350 (2003) 49Á
/
56
55
only in moderate to low yields. All hydrogenations were
carried out under mild conditions between 1 and 4 bar
hydrogen pressure. Results are listed in Table 3.
The hydrogen pressure has not affected the regios-
electivity, but strongly influences the turnover frequen-
cies (Table 3, runs 6Á9). When the reaction was carried
/
out in 2-propanol using catalyst 3L6 at 35 8C with a
molar substrate : catalyst (S/C) ratio of 1000:1, the
turnover frequency was 200 hꢂ1 at 0.4 bar of hydrogen
pressure. By increasing the H2 pressure to 1, 2, and 4 bar
the turnover frequencies were enhanced from 1204 via
1688 to 2439 hꢂ1
.
The excellent selectivity in the hydrogenation of only
the carbonyl group is reminiscent of a stoichiometric
reduction using NaBH4. However, only those complexes
were successful which were provided with 1,2-diamines.
If 1,3-diamines were employed as coligands the selectiv-
ity decreases in favor of the hydrogenation of the CÄ
bond (Table 3, runs 10Á13, and Scheme 2, C). Only in
the case of catalyst 3L4 a completely selective hydro-
genation of the CÄC function was observed with a low
/C
/
/
turnover frequency (Table 3, run 4, and Scheme 2, C). In
no case the complete hydrogenation to give B has been
observed (Table 3).
4. Conclusion
Scheme 2.
In this work a set of 11 novel (etherÁphosphine)-
/
ruthenium(II) complexes were made available which
were provided with different aliphatic and cycloaliphatic
diamines. The most valuable catalyst were those with
aliphatic and cycloaliphatic amines, they have been
proved to be highly active hydrogen catalysts with
excellent conversions and turnover frequencies even
CÄ
/
O and CÄ
/
C bonds resulting in the formation of the
saturated alcohol (B). 2-Propanol served as a solvent
reagent, but the catalysts were only active in the
presence of excess hydrogen and a cocatalyst (KOH)
[20Á23,30,31]. Aprotic and chlorinated solvents resulted
/
Table 3
Hydrogenation of trans-4-phenyl-3-butene-2-one a
Run
Catalyst
Conversion (%)b H2 (bar)
TOF c
Selectivity (%) b
A
B
C
1
2
2
32
67
3
126
673
0
100
100
0
0
0
0
0
0
0
0
0
0
0
0
0
0
100
0
3L1
3L2
3L4
3L5
3L6
3L6
3L6
3L6
3L7
3L8
3L8
3L9
2
3
100
17
3
1587
15
0
4
4
100
0
5
100
40
4
1240
200
100
100
100
100
100
79.5
76.4
82.4
71.6
6
0.4
1
0
7
100
100
100
100
61
1204
1688
2439
1500
610
0
8
2
0
9
4
0
20.6
10
11
12
13
1
1
23.6
17.6
23.4
97
100
4
1429
1000
4
a
b
c
Reaction was conducted at 35 8C using 3Á
/
5 g of substrate (S/Cꢁ1000) in 80 ml of 2-propanol [Ru:KOH:Substrate][1:10:1000].
/
Yields and selectivities were determined by GC.
hꢂ1).
ꢂ1
cat
TOF, turnover frequency (molsub mol

56
E. Lindner et al. / Inorganica Chimica Acta 350 (2003) 49Á56
/
[7] E. Lindner, A. Jager, F. Auer, W. Wielandt, P. Wegner, J. Mol.
¨
Catal. A 129 (1998) 91.
under mild conditions. Also they show a 100% selectiv-
ity toward the hydrogenation of the carbonyl function
[8] E. Lindner, Th. Schneller, F. Auer, P. Wegner, H.A. Mayer,
Chem. Eur. J. 3 (1997) 1833.
of the conjugated ketone trans-PhCHÄ
/
CHC(O)Me.
Only complex 3L4 was able to hydrogenate the CÄ
/C
[9] E. Lindner, Th. Schneller, F. Auer, H.A. Mayer, Angew. Chem.,
Int. Ed. 38 (1999) 2154.
[10] E. Lindner, A. Baumann, P. Wegner, H.A. Mayer, U. Reinohl, A.
¨
bond of the ketone, exclusively, however, with a low
conversion and turnover frequency.
Weber, T.S. Ertel, H. Bertagnolli, J. Mater. Chem. 10 (2000) 1655.
[11] E. Lindner, Th. Salesch, S. Brugger, F. Hoehn, P. Wegner, H.A.
Mayer, J. Organomet. Chem. 641 (2002) 165.
5. Supplementary material
[12] C. Nachtigal, S. Al-Gharabli, K. Eichele, E. Lindner, H.A.
Mayer, Organometallics 21 (2002) 105.
[13] A. Bader, E. Lindner, Coord. Chem. Rev. 27 (1991) 108.
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 179993 (3L2), and 179994
(3L8). Copies may be obtained free of charge from the
Director CCDC, 12 Union Road, Cambridge CB2 1EZ,
[14] E. Lindner, A. Mockel, H.A. Mayer, H. Kuhbauch, R. Fawzi, M.
¨
¨
Steimann, Inorg. Chem. 32 (1993) 1266.
[15] E. Lindner, St. Pautz, M. Haustein, Coord. Chem. Rev. 155
(1996) 145.
[16] E. Lindner, Q. Wang, H.A. Mayer, R. Fawzi, M. Steimann,
Organometallics 12 (1993) 1865.
[17] E. Lindner, K. Gierling, M. Geprags, R. Fawzi, M. Steimann,
¨
UK; fax: ꢀ44-1223-336 033; e-mail: deposit@ccdc.cam.
/
ac.uk or http://www.ccdc.cam.ac.uk/conts/retrieving.
html).
Inorg. Chem. 34 (1995) 6106.
[18] K. Abdur-Rashid, M. Faatz, A.J. Lough, R.H. Morris, J. Am.
Chem. Soc. 123 (2001) 7473.
[19] H. Doucet, T. Ohkuma, K. Murata, T. Yokozawa, M. Kozawa,
E. Katayama, A.F. England, T. Ikariya, R. Noyori, Angew.
Chem., Int. Ed. 37 (1998) 1703.
Acknowledgements
[20] K. Abdur-Rashid, A.J. Lough, R.H. Morris, Organometallics 20
(2001) 1047.
This work was supported by the Deutsche For-
schungsgemeinschaft (Graduiertenkolleg ‘Chemie in
Interphasen’ Grant No. 441/2-M, Bonn-Bad Godesberg,
Germany) and the Fonds der Chemischen Industrie. We
thank Dr. Zhong-Lin Lu, Samer Al-Gharabli, Mah-
moud Sunjuk and Adnan Al-Labadi, for helpful discus-
sions.
[21] R. Noyori, T. Ohkuma, Angew. Chem., Int. Ed. 40 (2001) 40.
[22] T. Ohkuma, H. Takeno, Y. Takeno, R. Noyori, Adv. Synth. Cat.
4 (2001) 343.
[23] K. Matsumura, S. Hashiguchi, T. Ikariya, R. Noyori, J. Am.
Chem. Soc. 119 (1997) 8738.
[24] A. Maj, K. Pietrusiewicz, I. Suisse, F. Agbossou, A. Mortreux, J.
Organomet. Chem. 626 (2001) 157.
[25] E. Lindner, I. Warad, K. Eichele, H.A. Mayer, unpublished
results.
[26] E. Lindner, S. Meyer, P. Wegner, B. Karle, A. Sickinger, B.
References
Steger, J. Organomet. Chem. 335 (1987) 59.
3
[27] A part of an AXX pattern: (a) Nꢁ
/
j JPCꢀ5
/
JPCj; (b) Nꢁ
/
[1] E. Lindner, Th. Salesch, S. Brugger, S. Steinbrecher, E. Plies, H.
Bertagnolli, H.A. Mayer, Eur. J. Inorg. Chem. (2002) 1998.
[2] E. Reddington, A. Sapienza, B. Gurau, R. Viswanathan, S.
Sarangapani, E.S. Smotkin, T.E. Mallouk, Science 280 (1998)
1735.
2
1
j JPCꢀ4
/
JPCj; (c) Nꢁ
/
j JPCꢀ3
JPCj.
/
[28a] G.M. Sheldrick, SHELXS-90, University of Gottingen, Gottingen,
¨ ¨
Germany, 1990.
[28b] G.M. Sheldrick, SHELXS-97, University of Gottingen, Gottingen,
¨
¨
Germany, 1997.
[3] R.H. Crabtree, Chem. Commun. (1999) 1611.
[4] Th. Bein, Angew. Chem., Int. Ed. 38 (1999) 323.
[5] E. Lindner, M. Kemmler, H.A. Mayer, P. Wegner, J. Am. Chem.
Soc. 116 (1994) 348.
[29] M.F. DaCruz, M. Zimmer, Inorg. Chem. 35 (1996) 2872.
[30] S. Hashiguchi, A Fujii, K.-J. Haack, K. Matszmwa, T. Ikariya, R.
Noyori, Angew. Chem., Int. Ed. Engl. 36 (1997) 285.
[31] R. Noyori, M. Yamakawa, S. Hashiguchi, J. Org. Chem. 66
(2001) 793.
[6] E. Lindner, R. Schreiber, Th. Schneller, P. Wegner, H.A. Mayer,
W. Gopel, Ch. Ziegler, Inorg. Chem. 35 (1996) 514.
¨