Chiral complexes of RhI containing binaphthalene-core P,S-heterobidentate ligands - Synthesis, characterization, and catalytic activity in asymmetric hydrogenation of α,β-unsaturated acids and esters

Article abstract of DOI:10.1002/ejic.200390077

The enantiopure complexes 3a and 3b [Rh(NBD)(P,S)]+BF₄^- [P,S = (S)-2-(diphenylphosphanyl)-2′-(methylthio)-1,1′-binaphthalene (a); (S)-2-(diphenylphosphanyl)-2′-(isopropylthio)-1,1′-binaphthalene (b) have been prepared from [Rh(NBD)(THF)₂]⁺BF₄^- by reaction with a stoichiometric amount of the appropriate P,S-heterobidentate ligand. Single-crystal X-ray analysis of the S-methyl derivative shows that the seven-membered chelate ring is locked in a boat-like conformation with the methyl group in the equatorial position. Variable-temperature NMR measurements confirm that this conformation is maintained in solution and that the dynamic behaviour displayed by the complex is due to pseudo-rotation of the diolefin. Complexes 3 have been tested in the asymmetric hydrogenation of α,β-unsaturated acids and esters. Enantioselectivities of up to 60% ee have been recorded. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Full text of DOI:10.1002/ejic.200390077

FULL PAPER
Chiral Complexes of RhI Containing Binaphthalene-Core P,S-Heterobidentate
Ligands ؊ Synthesis, Characterization, and Catalytic Activity in Asymmetric
Hydrogenation of α,β-Unsaturated Acids and Esters
Serafino Gladiali,*[a] Fabrizia Grepioni,[a] Serenella Medici,[a] Antonio Zucca,[a]
[b]
[c]
´
´
´
´
Zoltan Berente, and Laszlo Kollar
Keywords: S ligands / P ligands / Rhodium / Asymmetric catalysis / Hydrogenations
−
The enantiopure complexes 3a and 3b [Rh(NBD)(P,S)]+BF4
[P,S
naphthalene (a); (S)-2-(diphenylphosphanyl)-2Ј-(isopropyl- the dynamic behaviour displayed by the complex is due to
ial position. Variable-temperature NMR measurements con-
firm that this conformation is maintained in solution and that
=
(S)-2-(diphenylphosphanyl)-2Ј-(methylthio)-1,1Ј-bi-
thio)-1,1Ј-binaphthalene (b)] have been prepared from
pseudo-rotation of the diolefin. Complexes 3 have been
tested in the asymmetric hydrogenation of α,β-unsaturated
acids and esters. Enantioselectivities of up to 60% ee have
been recorded.
−
[Rh(NBD)(THF)2]+BF4 by reaction with a stoichiometric
amount of the appropriate P,S-heterobidentate ligand.
Single-crystal X-ray analysis of the S-methyl derivative
shows that the seven-membered chelate ring is locked in a
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
boat-like conformation with the methyl group in the equator- Germany, 2003)
Introduction
hemilabile character and to show a strong propensity to-
wards chelate coordination to the metal atom.[1]
An additional interesting feature of the S-donor of a sulf-
ide group is that upon coordination the S-centre becomes
stereogenic. The stereochemistry at the S-binding site de-
pends on the chiral backbone of the ligand and on the steric
demand of the alkyl substituent at the S-centre. This results
in the formation of diastereomeric complexes featuring
either a matching or a mismatching combination of chiral
elements; a fact that is expected to have a significant bear-
ing on the use of these ligands in asymmetric catalysis.
Various chiral P,S-heterobidentate ligands have been re-
ported recently. Phosphito sulfide derivatives based on the
xylofuranose framework have been used in the Ir-catalysed
asymmetric hydrogenation of itaconic acid (51% ee).[2] Glu-
copyranose-substituted phosphanyl sulfides are able to sta-
bilize otherwise elusive Pd0 complexes.[3]
Bis(phosphinite) ligands with a tetrahydrothiophene
backbone have been synthesised and used in rhodium-cata-
lysed enantioselective hydrogenation of methyl acetamidoc-
innamate. A tridentate coordination of the ligand, forming
thioether-bridged dinuclear species, has been proposed.[4]
Novel P,S-bidentate ligands possessing an oxathiane ring
condensed onto pulegone[5] or norbornane[6] moieties led to
quite good enantioselectivity in the Co-catalysed asymmet-
ric intramolecular PausonϪKhand reaction and in the Pd-
catalysed asymmetric allylic substitution reaction, respect-
ively.
The catalytic activity of transition metal complexes is lar-
gely dependent on the structure of the supporting ligands.
The nature of the donor atoms is crucial because it affects
substantially the electron density at the metal centre as well
as the geometric properties of the corresponding complexes.
Owing to the presence of two donors of diverse ligating
properties, bidentate P,X-heterodonor ligands, where the
chelate coordination of a phosphanyl group (P) is sup-
ported by a different heteroatom (X), are sometimes en-
dowed with a peculiar catalytic activity. Within the family
of P,X-heterobidentate ligands, the P,S-pair deserves par-
ticular attention. When the sulfur atom is in a low oxidation
state, as in sulfides, the softness of the S-donor is similar to
that of the P-donor in a phosphane. Phosphanyl sulfides
can be thus regarded as heterobidentate ligands that differ
little in the ligating strength of the two donors. Con-
sequently, such ligands are expected to have a fairly weak
[a]
`
Dipartimento di Chimica, Universita di Sassari,
Via Vienna 2, 07100 Sassari, Italia
Fax: (internat.) ϩ 39-079/212069, -229559
E-mail: gladiali@uniss.it
[b]
[c]
´
Institute of Biochemistry, University of Pecs and Research
Group for Chemical Sensors of the Hungarian Academy of
Sciences,
´
P. O. Box 266, 7601 Pecs, Hungary
´
Department of Inorganic Chemistry, University of Pecs and
Research Group for Chemical Sensors of the Hungarian
Academy of Sciences,
Mixed phosphorus/sulfur ligands, where the thioether
´
P. O. Box 266, 7601 Pecs, Hungary
fragment is flanked by a diarylphosphinito[7] or a diaryl-
556
 2003 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim 1434Ϫ1948/03/0203Ϫ0556 $ 20.00ϩ.50/0 Eur. J. Inorg. Chem. 2003, 556Ϫ561

Chiral Complexes of RhI Containing Binaphthalene-Core P,S-Heterobidentate Ligands
FULL PAPER
phosphanyl[8] unit supported on chiral 1,2-disubstituted
aliphatic backbones, proved to be highly efficient in Pd-
catalysed enantioselective allylic substitution and in Rh-
catalysed hydrogenation, respectively.
Atropisomeric 1,1Ј-binaphthyl-templated diphosphanes
such as BINAP are among the most efficient chiral ligands
for asymmetric hydrogenation. Recently, we reported on the
synthesis of BINAPS,[9] a heterobidentate version of BI-
NAP in which one of the two diphenylphosphanyl substitu-
ents is replaced by an alkylthio group. BINAPS derivatives
performed well in some Pd-catalysed asymmetric reactions,
such as allylic alkylation[10] and hydrosilylation,[11] but were
less satisfactory in Rh-catalysed processes such as hydrofor-
mylation and H-transfer reduction.[11]
We report here on further investigations into the prepara-
tion, dynamic behaviour and utilization in enantioselective
hydrogenation of such BINAPS-based Rh complexes.
Figure 1. Ball-and-stick representation of the cationic complex in
˚
3a; selected structural parameters [A]: Rh(1)ϪC(34) 2.200(5),
Rh(1)ϪC(35) 2.216(5),Rh(1)ϪC(37) 2.181(5), Rh(1)ϪC(38)
2.144(6), Rh(1)ϪP(1) 3.290(1), Rh(1)ϪS(1) 2.343(1), P(1)ϪC(20)
1.838(4), S(1)ϪC(1) 1.793(4), C(34)ϪC(35) 1.385(7), C(37)ϪC(38)
1.356(9); the longest contacts involving H(2) and the HMe atoms
are shown by dotted lines; all remaining H atoms omitted for clar-
ity
Results and Discussion
The required ligands (S)-1a and (S)-1b were synthesised
in enantiopure form as reported previously.[11] The prepara-
tion of the enantiopure complexes 3a and 3b was accomp-
lished as reported in Scheme 1 by treating the rhodium
The H atom bound to C(2) is in close contact with the
hydrogen atoms of the methyl group on the S atom; if free
reorientation of the methyl group is assumed, the ‘‘dy-
namic’’ contacts between the H atoms range from 1.84 to
Ϫ
complex [Rh(NBD)(THF)2]ϩBF4 (2) (NBD ϭ 1,4-nor-
bornadiene) with a stoichiometric amount of (S)-1a and
(S)-1b, respectively. The required intermediate adduct 2 was
prepared in situ from the corresponding chloro-bridged
dimer [Rh(NBD)Cl]2 and AgBF4.[12] The isolated yields of
the complexes 3a and 3b were in the range of 60Ϫ70%.
˚
˚
2.46 A (assuming a normalised distance of 1.08 A for the
C
(by)ϪH group). One of the two extremes, with two equiva-
˚
lent HCH···HMe contacts of 2.46 A, is shown in Figure 1.
Contrary to the BINAP complex, where the seven-mem-
bered chelate ring adopts a skew conformation in the solid
state,[13] the seven-membered ring in 3a adopts a boat-like
conformation (see Figure 2), with the Rh(1), P(1), C(10),
and C(1) atoms constituting the flat part of the boat (max-
˚
imum deviation from the average plane 0.05 A). The sulfur
and Cmethyl atom elevations from this plane are 1.21 and
˚
1.28 A, respectively; thus, the methyl group bound to the
sulfur atom is in an equatorial position with respect to the
ring.
Scheme 1. Synthesis of complexes 3a and 3b
The molecular structure of the complex cation 3a is de-
picted in Figure 1, together with the labelling scheme.
The Rh atom has a square-planar coordination geometry
involving the double bonds of the norbornadiene ligand,
the P atom and the stereogenic S-donor. The configuration
at the newly created S-stereocentre is (R). The RhϪP and
RhϪC bond lengths are comparable to those previously ob-
served in [Rh(NBD)(BINAP)]ϩ.[13] The dihedral angle be-
tween the two naphthyl ligands (ca. 75°) is comparable to
the 74.4° observed in the BINAP complex.
Figure 2. Boat-like conformation adopted by the seven-membered
chelate ring in complex cation 3a
Eur. J. Inorg. Chem. 2003, 556Ϫ561
557

´
S. Gladiali, F. Grepioni, S. Medici, A. Zucca, Z. Berente, L. Kollar
FULL PAPER
Crystalline 3a contains a stoichiometric amount of location of the S-methyl group and confirms that the solid-
CHCl3 solvent per formula unit. The H atom belonging to state structure is preserved in solution.
the solvent molecule interacts via bifurcated hydrogen
The pattern of the aromatic protons undergoes some mi-
Ϫ
bonding of the CH···F type with the BF4 anion (see Fig- nor variation with temperature, but the isolated peaks re-
ure 3). The (C)H···F distances (after normalisation of the main sharp and the coupling constants are substantially un-
˚
CϪH distance to the neutron value of 1.08 A) are 2.26(1) changed.
˚
and 2.24(1) A, and compare well with the shortest CH···F
The protons were assigned to the corresponding carbon
interactions observed for organometallic salts containing atoms by a H-13C HSQC experiment. In the 13C NMR
1
Ϫ
Ϫ
BF4 or PF6 anions.[14]
spectrum all the carbon signals but those at δ ϭ 81.61,
71.25, and 66.50 ppm show sharp lines. These were assigned
to the olefinic and the methylenic carbon atoms of norbor-
nadiene, respectively. Finally, the sharp doublet in the 31P
NMR spectrum [1J(Rh,P) ϭ 161.7 Hz] was not affected by
the temperature variation.
The NOESY experiments show that the SϪCH3 group
gives cross peaks with both olefinic signals at δ ϭ 4.40 and
4.67 ppm. This tells us that the two vinylic protons of the
same double bond of NBD are not averaged and provides
further evidence for the equatorial position of the methyl
group. If the methyl group were axial, only one of the two
protons on the same double bond would give a cross peak
(Figure 5).
Figure 3. Bifurcated CH···F hydrogen bond interaction between the
Ϫ
CHCl3 solvent molecule and BF4
The NOESY spectra also show close contacts between
the naphthyl proton adjacent to the S atom (signal at δ ϭ
One of the phenyl substituents bound to the phosphorus 7.67 ppm) and the olefinic proton of NBD (signal at δ ϭ
atom and the portion of the binaphthyl moiety bound to 4.67 ppm). Thus, the more deshielded olefinic signal could
S(1) are arranged in a π-stacking fashion, with an average confidently be assigned to the olefinic proton Ha (Hd) loc-
˚
distance between the two mean planes of ca. 3.5 A (see Fig- ated below the average plane of the chelate ring (Figure 5).
ure 1).
The olefinic protons (signals at δ ϭ 4.40 and 4.67 ppm)
1
In the H NMR spectrum of 3a (CDCl3 solution) four also show contacts with the ortho protons of the two differ-
lines, each one accounting for two protons, can be observed ent phenyl substituents of the PPh2 unit (signals at δ ϭ 7.38
for the coordinated NBD at 303 K (Figure 4). The signals and 7.41 ppm).
of the allylic (δ ϭ 4.04 ppm) and the olefinic protons (δ ϭ
These NMR experiments indicate that the dynamic pro-
4.40 and 4.67 ppm) are broad singlets, while the bridging cess the complex experiences in solution results in averaging
methylene group resonates as a sharp singlet (δ ϭ protons Ha with Hd and protons Hb with Hc (see Figure 5).
1.50 ppm). When the temperature is lowered to 273 K, the
Dynamic behaviour of this type has been previously ob-
olefinic protons’ signal at δ ϭ 4.67 ppm undergoes line served in cationic (diolefin)rhodium complexes with bident-
broadening, becoming extremely broad at 258 K and prac- ate P,S- or P,N-ligands. This has been attributed to a mech-
tically disappearing at 243 K. The second olefinic signal at anism involving RhϪS[15,16] or RhϪN[16] bond dissociation,
δ ϭ 4.40 ppm also broadens, but at lower temperatures [ν(1/ followed by rotation around the remaining RhϪP bond and
2) ഠ 20 Hz at 258 K], and practically disappears at 223 K. subsequent recombination of the dissociated bond.
The allylic and the methylenic signals at δ ϭ 4.04 and
Although the S-stereocentre might be labilised more
1.50 ppm, respectively, are still observable even at 223 K readily than the P-centre, the present NMR evidence indic-
[(ν(1/2) ഠ 40 Hz and 25 Hz, respectively]. From the NMR ates that the sulfur atom remains tightly bound to the metal
spectroscopic data it is apparent that a dynamic process is atom throughout. Chemical shift, coupling constant and
occurring in solution which averages the protons of the sharpness of the signal of the S-methyl group remain un-
NBD ligand in the bound state.
changed over the temperature range investigated. No shift
The methyl peak appears at δ ϭ 2.59 ppm as a sharp of the methyl group towards that of the free ligand is ob-
3
doublet (J ϭ 1.5 Hz). This is due to J(Rh,H) coupling as served; such a shift would be expected if the sulfur donor
demonstrated by a selective 1H{31P} decoupling. The shape, were displaced from the metal atom. Furthermore, the
chemical shift and coupling constant of this signal remain doublet at δ ϭ 6.01 ppm, regarded as diagnostic of the che-
unchanged over the whole temperature range investigated late coordination of the binaphthyl ligand, remains un-
(303Ϫ203 K), suggesting that in this interval no dissoci- changed from 223 to 303 K.
ation of the S-donor from the metal atom occurs. Irradi-
All this evidence indicates that dissociation/inversion pro-
ation of this peak causes a significant NOE enhancement cesses at the sulfur atom or conformational interconver-
of the signal at δ ϭ 7.67 ppm which should be attributed sions of the seven-membered ring do not take place. In-
to the naphthyl proton on the carbon atom adjacent to the stead, it appears that in solution both the chelate coordina-
S-substituted one. This is consistent with an equatorial tion of the P,S-ligand and the configurational integrity of
558
Eur. J. Inorg. Chem. 2003, 556Ϫ561

Chiral Complexes of RhI Containing Binaphthalene-Core P,S-Heterobidentate Ligands
FULL PAPER
1
Figure 4. Variable-temperature H NMR spectrum of 3a
ant change with respect to those registered in plain CDCl3.
As it seems even more unlikely that the phosphorus atom
is involved in a displacement/recombination process, the ob-
served results should be ascribed to a dynamic process of
the diolefin. This should proceed through an olefin pseudo-
rotation, prompted by dissociation of one rhodiumϪolefin
bond, followed by rotation through 180° around the re-
maining RhϪolefin bond and subsequent rebuilding of the
chelate coordination of the diolefin. This conclusion fits
better the experimental finding that the dynamic behaviour
of the NBD protons is far more pronounced than that of
the protons of the backbone of the P,S-ligand.
The isopropyl derivative 3b shows in solution the same
dynamic behaviour as 3a as judged from the similar NMR
pattern. The methylenic, allylic and olefinic protons of the
norbornadiene ligand give rise to four broad singlets at δ ϭ
1.49, 4.00, 4.48, and 4.61 ppm (2 H each), respectively. The
signals of the diastereotopic methyl groups of the isopropyl
group appear at δ ϭ 1.18 and 1.28 ppm. The chelating coor-
dination of 1b is confirmed by the presence of the aromatic
doublet at δ ϭ 5.95 ppm.
Figure 5. Representation of NOE contacts in 3a
the S-stereocentre in the bound state are preserved over the
temperature range investigated.
An alternative plausible mechanism involves a Barry
pseudo-rotation promoted by coordination of a donor at
the fifth position of the metal atom. Such a reaction path
Asymmetric Hydrogenation of α,β-Unsaturated Acids and
Esters
Hydrogenation tests were performed on acrylic acid de-
has been proposed previously for a (1,5-cycloctadiene)Rh rivatives 4aϪ4c (Scheme 2) at room temperature in meth-
complex containing 2-(diphenylphosphanyl)pyridine.[17] anol/benzene (1:1). A slight positive pressure of hydrogen
1
However, this possibility was not substantiated as the H was employed because at 1 bar the reaction was too slug-
NMR spectra registered in CDCl3 after addition of donor gish. Even so, the catalytic activity of complexes 3a and 3b
solvents such as THF, or in [D6]acetone, show no signific- was rather low and fairly long reaction times were required
Eur. J. Inorg. Chem. 2003, 556Ϫ561
559

´
S. Gladiali, F. Grepioni, S. Medici, A. Zucca, Z. Berente, L. Kollar
FULL PAPER
to attain a satisfactory conversion (Table 1). The two com-
Further work is in progress to determine the effect of a
plexes exhibited comparable catalytic activity and both led substituent of higher steric demand on the sulfur atom, and
to products of the same (R) configuration, although the whether this situation can be reversed by introducing a
methyl derivative 3a was notably more efficient than the bulkier group such as tert-butyl on this donor centre.
isopropyl counterpart 3b and in all runs produced much
higher ees.
Experimental Section
1
General: Some H, 31P, and 13C NMR spectra, as well as NOESY
measurements (mixing time ϭ 500 ms) were carried out with a
Varian VXR-S 300 instrument at 299.9 MHz, 121.4 MHz and
1
75.4 MHz, respectively. H and 31P variable-temperature measure-
Scheme 2. Asymmetric hydrogenation of α,β-unsaturated carb-
oxylic acids and esters 4aϪ4c
1
ments at 400 MHz and 161.9 MHz, respectively, as well as H-13C
HSQC experiments were run with a Varian INOVA 400 WB spec-
trometer using a Highland VT unit. Chemical shifts, given in ppm,
are referred to internal TMS (1H and 13C) or external 85% H3PO4
(31P); coupling constants are in Hz. The two-dimensional experi-
Under our reaction conditions, the acid 4b was hydrogen-
ated with 49% ee by 3a. This is basically the same ee ob-
tained with the Rh complex with BINAPPЈ [2-(Diphenyl-
phosphanyl)-2Ј-(di-o-tolylphosphanyl)-1,1Ј-binaphthalene]
(46% ee) and is much higher than the 13% ee we obtained
with the corresponding Rh complex with BINAP.[18]
1
ments (NOESY and H-13C HSQC) were performed using stand-
ard pulse sequences. Solvents were dried and distilled under nitro-
gen before use. All the reactions were performed under argon.
[Rh(NBD)Cl]2 was purchased from Strem Chemicals and used
without further purification. The ligands, (S)-2-(diphenylphos-
phanyl)-2Ј-(methylthio)-1,1Ј-binaphthalene (1a) and (S)-2-(di-
The improvement over the chelate diphosphane-based
catalysts was more pronounced with the methyl ester 4a
where ees obtained with BINAP (21%) and BINAPPЈ
(40%)[18] were outperformed by that obtained with complex
3a (60%). This value is among the highest obtained in Rh-
catalysed asymmetric hydrogenation using chiral P,S-heter-
odonor ligands. It is also close to that reported for the hy-
drogenation of the acid 4b with a preformed [(S)-
phenylphosphanyl)-2Ј-(isopropylthio)-1,1Ј-binaphthalene
(1b),
were prepared as previously reported.[11] The ees of the samples
from the catalytic runs were determined with a Hewlet Packard
5890A gas chromatograph fitted with a 25-m capillary column co-
ated with diethyl tert-butylsilyl-β-cyclodextrin PS 086 (i.d.
0.25 mm), purchased from MEGA (Legnano, Italia), using He as
the carrier (head pressure 60 kPa, split ratio 100).
Ϫ
(BINAP)Rh(MeOH)2]ϩClO4 complex (67% ee).[19]
Preparation of [(S)-2-(Diphenylphosphanyl)-2Ј-(methylthio)-1,1Ј-bi-
Both complexes 3a and 3b proved to be effective in hy-
drogenating dimethyl itaconate (4c), leading to high conver-
naphthalene](2,5-norbornadiene)rhodium(i) Tetrafluoroborate (3a):
AgBF4 (39 mg, 0.2 mmol) was added to
a
solution of
sions (93 and 94%, respectively). Unfortunately, this activity [Rh(NBD)Cl]2 (48 mg, 0.1 mmol) in THF (10 mL). After stirring
for 1 h, the mixture was filtered through Celite and (S)-2-(di-
phenylphosphanyl)-2Ј-(methylthio)-1,1Ј-binaphthalene (100 mg,
was not matched by a high selectivity, and ees were de-
cidedly poor both with 3a and 3b (8% and 2% ee, respect-
ively).
In all these experiments the prevailing enantiomer
showed the (R) configuration, the same as obtained with
(S)-BINAP and (S)-BINAPPЈ. Therefore, the stereochem-
istry of the hydrogenation of these substrates is basically
driven by the handedness of the chiral backbone; the stereo-
genicity at the sulfur plays a minor, albeit cooperative role,
in the transfer of the chiral information.
0.2 mmol) was added to the resulting yellow solution. A yellow
solid precipitated immediately and was recovered by filtration.
Yield 107 mg (70%). Crystals of 3aCHCl3 suitable for X-ray struc-
ture determination were obtained by slow concentration of a chlo-
roform solution. 1H NMR (CDCl3 298 K): δ ϭ 1.50 [br. s, 2 H,
CH2 (NBD)], 2.59 (d, J ϭ 1.5 Hz, 3 H, SCH3), 4.04 [br. s, 2 H,
allylic CH (NBD)], 4.40 and 4.67 [br. s, 2 ϫ 2 H, olefinic CH
(NBD)], 6.01 (d, J ϭ 8.6 Hz, 1 H, Ar), 6.76Ϫ6.8 (m, 4 H, Ar), 6.88
(d, J ϭ 8.6 Hz, 1 H, Ar), 7.20Ϫ7.26 (m, 2 H), 7.30Ϫ7.44 (m, 4 H),
Table 1. Asymmetric hydrogenation of α,β-unsaturated acids and esters 4aϪ4c catalysed by complexes 3a and 3b (substrate/catalyst ϭ
100:1)
Substrate.
R
X
Catalyst.
p(H2) [bar]
t [h]
Conversion[a]
[%]
ee[a] [%]
Conformation
4a
4b
4c
4a
4b
4c
CH3
H
CH3
CH3
H
NHCOCH3
NHCOCH3
CH2COOCH3
NHCOCH3
NHCOCH3
CH2COOCH3
3a
3a
3a
3b
3b
3b
2.6
2.3
1.9
1.9
4.1
4.6
16
16
16
11
16
16
13
31
93
11
33
94
60
49
8
27
11
2
(R)
(R)
(R)
(R)
(R)
(R)
CH3
[a]
Determined by gas chromatography.
560
Eur. J. Inorg. Chem. 2003, 556Ϫ561

Chiral Complexes of RhI Containing Binaphthalene-Core P,S-Heterobidentate Ligands
FULL PAPER
[1]
7.51Ϫ7.59 (m, 5 H), 7.67 (d, J ϭ 8.1 Hz, 1 H, Ar), 7.94 (d, J ϭ
8.1 Hz, 1 H, Ar), 7.97 (d, J ϭ 8.1 Hz, 1 H, Ar), 8.06 (d, J ϭ 8.9 Hz,
1 H, Ar), 8.18 (d, J ϭ 8.9 Hz, 1 H, Ar) ppm. 31P{1H} NMR
C. S. Slone, D. A. Weinberger, C. A. Mirkin, ‘‘The Transition
Metal Coordination Chemistry of Hemilabile Ligands’’, in:
Progress in Inorganic Chemistry (Ed.: K. D. Karlin), John
Wiley and Sons, New York, 1999, vol. 48, p. 233.
O. Pamies, M. Dieguez, G. Net, A. Ruiz, C. Claver, Organomet-
allics 2000, 19, 1488Ϫ1496.
M. Tschoerner, G. Trabesinger, A. Albinati, P. S. Pregosin, Or-
ganometallics 1997, 16, 3447Ϫ3453.
E. Hauptman, R. Shapiro, W. Marshall, Organometallics 1998,
17, 4976Ϫ4982.
1
(CDCl3, 298 K): δ ϭ 27.1 [d, J(Rh,P) ϭ 161.7 Hz] ppm. 13C{1H}
[2]
[3]
`
´
NMR (CDCl3, 298 K): δ ϭ 15.27 (SCH3), 52.99 (allylic CH, NBD),
66.50 (NBD CH2), 71.25 (olefinic CH, NBD), 81.61 (olefinic CH,
NBD), 123.30Ϫ135.09 (32 C, Ar) ppm.
[4]
Preparation of [(S)-2-(Diphenylphosphanyl)-2Ј-(isopropylthio)-1,1Ј-
binaphthalene](2,5-norbornadiene)rhodium(i) Tetrafluoroborate (3b):
[5]
`
X. Verdaguer, A. Moyano, M. A. Pericas, A. Riera, M. A.
Compound 3b was obtained by the procedure described for 3a ex-
cept that after the addition of the ligand (S)-2-(diphenylphos-
phanyl)-2Ј-(isopropylthio)-1,1Ј-binaphthalene an orange solution
was obtained. The solution was stirred for 1 h then concentrated.
The orange precipitate formed after addition of pentane was reco-
´
Maestro, J. Mahıa, J. Am. Chem. Soc. 2000, 122, 10242Ϫ10243.
[6]
H. Nakano, Y. Okuyama, M. Yanagida, H. Hongo, J. Org.
Chem. 2001, 66, 620Ϫ625.
[7]
D. A. Evans, K. R. Campos, J. S. Tedrow, F. E. Michael, M.
´
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1
E. Hauptmann, P. J. Fagan, W. Marshall, Organometallics
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δ ϭ 1.18 (d, J ϭ 6.6 Hz, 3 H, CH3), 1.28 (d, J ϭ 6.6 Hz, 3 H,
CH3), 1.50 [s, 2 H, CH2 (NBD)], 3.88 (sept, J ϭ 6.6 Hz, 1 H, CH),
4.00 [s, 2 H, allylic CH (NBD)], 4.50 [s, 2 H, olefinic CH (NBD)],
4.6 [s, 2 H, olefinic CH (NBD)], 5.95 (d, J ϭ 8.1 Hz, 1 H, Ar),
6.71Ϫ6.80 (m, 4 H, Ar), 6.94 (d, J ϭ 8.4 Hz, 1 H, Ar), 7.21Ϫ7.58
(m, 11 H, Ar), 7.73 (d, J ϭ 7.8 Hz, 1 H, Ar), 7.98 (m, 2 H, Ar),
8.14 (d, J ϭ 8.7 Hz, 1 H, Ar), 8.27 (d, J ϭ 8.7 Hz, 1 H, Ar) ppm.
[9]
[10]
[11]
[12]
[13]
1
31P{1H} NMR (CDCl3, 298 K): δ ϭ 26.8 [d, J(Rh,P) ϭ 161 Hz]
ppm. [α]2D5 ϭ Ϫ386 (c ϭ 0.5, CHCl3).
K. Toriumi, T. Ito, H. Takaya, T. Souchi, R. Noyori, Acta
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in: Current Challenges on Large Supramolecular Assemblies
(Ed.: G. Tsoucaris), Kluwer Academic Publishers, Dordrecht,
The Netherlands, 1998, p. 173.
X-ray Structural Determination of 3a: X-ray diffraction data for 3a
were collected at 293 K with a Bruker diffractometer (SMART)
˚
(Mo-Kα radiation, λ ϭ 0.71073 A) and corrected for absorption.
C41H32BCl3F4PRhS, Mr ϭ 883.77, triclinic, space group P1, a ϭ
˚
9.1724(7), b ϭ 10.7757(7), c ϭ 10.9453(8) A, α ϭ 68.456(2), β ϭ
[15]
3
A. Albinati, J. Eckert, P. S. Pregosin, H. Rüegger, R. Salzmann,
C. Stössel, Organometallics 1997, 16, 579Ϫ590.
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1984, 40, 1245. In a previous work we failed to reproduce
this result.
˚
88.282(2), γ ϭ 72.591(2)°, V ϭ 956.2(1) A , Z ϭ 1, dc
ϭ
1.535 g·cmϪ3, µ ϭ 0.802 mmϪ1, F(000) ϭ 446, 11681 reflections
measured, refinement on F2 (8621 independent reflections) for 446
parameters, wR2 (on F2, all data) ϭ 0.0906, R1 [on F, I Ͼ 2σ(I)] ϭ
0.0358. The computer program SHELXL-97[20] was used for struc-
ture solution and refinement. All non-H atoms were treated aniso-
tropically. The naphthyl moieties were refined as rigid groups. Hy-
drogen atoms were added in calculated positions and refined riding
on their respective C atoms. For all molecular representations the
graphic program SCHAKAL99[21] was used. Intermolecular inter-
actions were calculated by means of the program PLATON.[22]
CCDC-189656 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge at
www.ccdc.cam.ac.uk/conts/retrieving.html or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge
[16]
[17]
[18]
[19]
[20]
G. M. Sheldrick, SHELXL-97, Program for Crystal Structure
Determination; University of Göttingen, Göttingen, Germany,
1997.
E. Keller, SCHAKAL99, Graphical Representation of Molecular
Models; University of Freiburg, Germany, 1999.
PLATON: A. L. Spek, Acta Crystallogr., Sect. A 1990, 46, C31.
[21]
[22]
CB2 1EZ, UK [Fax: (internat.)
deposit@ccdc.cam.ac.uk].
ϩ 44-1223/336-033; E-mail:
Received July 14, 2002
[I02384]
Eur. J. Inorg. Chem. 2003, 556Ϫ561
561