Palladium and platinum complexes with a β-cyclodextrin-functionalized phosphine ligand

Article abstract of DOI:10.1021/om000634e

Treatment of o-Ph₂PC₆H₄CHO with 6-H₂NCH₂CH₂NH-β-CD (CD = cyclodextrin) produced 6-(o-Ph₂PC₆H₄CH=NCH₂ CH₂NH)-β-CD (CDNNP), which reacted with MCl₂(COD) (M = Pd, Pt) and [PdCl(η³-C₃H₅)]₂ to give [MCl(CDNNP)]Cl and [PdCl(η¹-C₃H₅) (CDNNP)]Cl, respectively.

Full text of DOI:10.1021/om000634e

424
Organometallics 2001, 20, 424-429
P a lla d iu m a n d P la tin u m Com p lexes w ith a
â-Cyclod extr in -F u n ction a lized P h osp h in e Liga n d
Chuluo Yang, Yuk King Cheung, J unzhi Yao, Yiu Tung Wong, and Guochen J ia*
Department of Chemistry, The Hong Kong University of Science and Technology,
Clear Water Bay, Kowloon, Hong Kong
Received J uly 21, 2000
Treatment of o-Ph2PC6H4CHO with 6-H2NCH2CH2NH-â-CD (CD ) cyclodextrin) produced
6-(o-Ph2PC6H4CHdNCH2CH2NH)-â-CD (CDNNP), which reacted with MCl2(COD) (M ) Pd,
Pt) and [PdCl(η3-C3H5)]2 to give [MCl(CDNNP)]Cl and [PdCl(η1-C3H5)(CDNNP)]Cl, respec-
tively.
In tr od u ction
have received considerable attention in recent years.6,7
In addition, as cyclodextrins are water-soluble, it may
be possible to carry out catalytic reactions with these
systems in water or biphasic medium.8 Despite the
potentials, reported cyclodextrin-functionalized phos-
phine ligands and their metal complexes are still very
limited.9-12 The purpose of this paper is to report the
Cyclodextrins (CDs) are bucket-shaped cyclic glucose
oligomers with hollow hydrophobic cavities.1 One of the
most interesting properties of cyclodextrins is that they
can form inclusion complexes with selected organic/
inorganic guest molecules. Because of this unique
property, cyclodextrins and their derivatives have been
widely studied as models for enzymatic reactions.2 A
common approach to develop artificial enzymes based
on cyclodextrins is to functionalize cyclodextrins with
proper coenzyme factors. As many transition-metal
complexes are catalytically active for various reactions,
it would be interesting to attach them to cyclodextrins
and to study the catalytic properties of the resulting
complexes. Until now, reported metal complexes at-
tached to cyclodextrins have been mainly those with
nitrogen and/or oxygen donor ligands.3,4
As phosphines are excellent ligands to stabilize a
variety of metal complexes and have been used widely
in homogeneous catalysis,5 it is desirable to function-
alize cyclodextrins with phosphine ligands. In principle,
cyclodextrin-functionalized phosphine ligands can sup-
port the active metal centers through the phosphine
functionalities and, in the meantime, can interact with
substrates by means of secondary interaction through
cyclodextrins’ hydrophobic cavities and/or groups on the
outer surface of the torus, which may improve regio-
and stereoselectivity in catalytic reactions. The design,
synthesis, and characterization of new ligands that can
interact with substrates through secondary interaction
(6) Sawamura, M.; Ito, Y. Chem. Rev. 1992, 92, 857 and references
therein.
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A.; Somsook, E. Organometallics 2000, 19, 994 and references therein.
(b) Kimmich, B. F. M.; Landis, C. R.; Powell, D. R. Organometallics
1996, 15, 4141 (c) MacFarland, D. K.; Landis, C. R. Organometallics
1996, 15, 483. (d) J iang, Y.; J iang, Q.; Zhang, X. J . Am. Chem. Soc.
1998, 120, 3817. (e) Sawamura, M.; Nakayama, Y.; Tang, W. M.; Ito,
Y. J . Org. Chem. 1996, 61, 9090. (f) Achiwa, I.; Yamazaki, A.; Achiwa,
K. Synlett 1998, 45. (g) Heller, D.; Holz, J .; Borns, S.; Spannenberg,
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Ed. Engl. 1993, 32, 1524 and references therein. (b) Kalck, P.; Monteil,
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1993, 4, 1829.
(11) Deshpande, R. M.; Fukuoka, A.; Ichikawa, M. Chem. Lett. 1999,
13.
(12) Armspach, D.; Matt, D. Chem. Commun. 1999, 1073.
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Leeuwen, P. W. N. M.; Vrieze, K.; Fraanje, J .; Goubitz, K.; Spek, A. L.
Organometallics 1996, 15, 3022.
(14) Crociani, B.; Antonaroli, S.; Bandoli, G.; Canovese, L.; Visentin,
F.; Uguagliati, P. Organometallics 1999, 18, 1137.
(15) (a) Reddy, K. R.; Chen, C. L.; Liu, Y. H.; Peng, S. M.; Chen, J .
T.; Liu, S. T. Organometallics 1999, 18, 2574. (b) Van den Beuken, E.
K.; Veldman, N.; Smeets, W. J . J .; Spek, A. L.; Feringa, B. L.
Organometallics 1998, 17, 636. (c) Wong, W. K.; Zhang, L.; Xue, F.;
Mak, T. C. W. Chem. Commun. 1997, 1525. (d) Barbaro, P.; Bianchini,
C.; Laschi, F.; Midollini, S.; Moneti, S.; Scapacci, G.; Zanello, P. Inorg.
Chem. 1994, 33, 1622. (e) Pelagatti, P.; Bacchi, A.; Carcelli, M.; Costa,
M.; Fochi, A.; Ghidini, P.; Leporati, A.; Leporati, E.; Masi, M,; Pelizzi,
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(1) (a) Szejtli, J . Chem. Rev. 1998, 98, 1743. (b) Connors, K. A. Chem.
Rev. 1997, 97, 1325 and references therein. (c) Wentz, G. Angew.
Chem., Int. Ed. Engl. 1994, 33, 803.
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(b) Lincoln, S. F. Coord. Chem. Rev. 1997, 166, 255.
(4) For recent work on metal-containing CDs, see for example: (a)
French, R. R.; Holzer, P.; Leuenberger, M. G.; Woggon, W. D. Angew.
Chem., Int. Ed. 2000, 39, 1267. (b) Ferreira, P.; Goncalves, I. S.;
Pillinger, M.; Rocha, J .; Santos, P.; Teixeira-Dias, J . J . C. Organome-
tallics 2000, 19, 1455. (c) Weidner, M.; Pikramenou, Z. Chem. Commun.
1998, 1473. (d) Charbonnier, F.; Humbert, T.; Marsura, A. Tetrahedron
Lett. 1998, 39, 3481. (e) Zhang, B.; Breslow, R. J . Am. Chem. Soc. 1997,
119, 1676. (f) Rezac, M.; Breslow, R. Tetrahedron Lett. 1997, 33, 5763.
(g) Corrandini, R.; Dossena, A.; Galaverna, G.; Marchelli, R.; Panagia,
A.; Sartor, G. J . Org. Chem. 1997, 62, 6283 and references therein.
(5) Pignolet. L. H. Ed.; Homogeneous Catalysis with Metal Phosphine
Complexes; Plenum Press: New York, 1983.
(16) Kuznetsov, V. F.; Facey, G. A.; Yap, G. P. A.; Alper, H.
Organometallics 1999, 18, 4706 and references therein.
(17) (a) Pfeiffer, J .; Kickelbick, G.; Schubert, U. Organometallics
2000, 19, 957. (b) Pfeiffer, J .; Kickelbick, G.; Schubert, U. Organome-
tallics 2000, 19, 62. (c) Nishibayashi, Y.; Takei, I.; Uemura, S.; Hidai,
M. Organometallics 1999, 18, 2291. (d) Bei, X.; Uno, T.; Norris, J .;
Turner, H. W.; Weinberg, W. H.; Guram, A. S.; Petersen, J . L.
Organometallics 1999, 18, 1840. (e) La Torre, F. G.; J alo´n, F. A.; Lo´pez-
Agenjo, A.; Manzano, B. R.; Rodr´ıguez, A.; Sturm, T.; Weissensteiner,
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10.1021/om000634e CCC: $20.00 © 2001 American Chemical Society
Publication on Web 12/30/2000

Pd and Pt Complexes with a Phosphine Ligand
Organometallics, Vol. 20, No. 3, 2001 425
Sch em e 1
synthesis and characterization of a potentially triden-
tate â-cyclodextrin-functionalized NNP mixed donor
ligand and its palladium and platinum complexes.
Phosphorus-nitrogen mixed donor ligands either bi-
dentate or polydentate in nature are very useful ligands
in organometallic chemistry and catalysis.13-18
Resu lts a n d Discu ssion
Rea ction of o-P h 2P C6H4CHO w ith H2NCH2CH2-
NHCH3. Reactions of o-Ph2PC6H4CHO with appropriate
amines R-NH2 have been successfully employed previ-
ously to prepare potentially bidentate or polydentate
iminophosphine ligands.13-15 It is therefore expected
that the novel phosphine ligand 6-(o-Ph2PC6H4CHd
NCH2CH2NH)-â-CD (CDNNP) may also be obtained
from the reaction of o-Ph2PC6H4CHO with the easily
accessible amine-modified â-cyclodextrin 6-NH2CH2CH2-
NH-â-CD.19 The closely related ligand o-Ph2PC6H4CHd
NCH2CH2-2-pyridine has been previously prepared from
the reaction of o-Ph2PC6H4CHO with 2-(2-aminoethyl)-
pyridine.13
As 6-NH2CH2CH2NH-â-CD is only soluble in polar
solvents such as DMSO, methanol, and DMF, one might
expect that the phosphine ligand CDNNP as well as its
metal complexes may also have low solubility. The low
solubility together with high molecular weights would
make characterization of the compounds by NMR a
more difficult task. To facilitate the characterization of
the cyclodextrin-modified phosphine ligand and its
metal complexes and to make future comparative study
on the catalytic properties of systems with and without
the CD substituent, we initially attempted to prepare
the analogous ligand Ph2PC6H4CHdNCH2CH2NHMe
(NNP) from the reaction of o-Ph2PC6H4CHO with H2-
NCH2CH2NHCH3. It should be easy to fully characterize
the ligand Ph2PC6H4CHdNCH2CH2NHMe and its metal
complexes.
1a to give 1b by carrying out the reaction for longer
reaction times or under refluxing were not successful.
For example, the relative amount of 1a only decreased
slightly after a mixture of H2NCH2CH2NHCH3 and
o-Ph2PC6H4CHO in THF was allowed to stand at room
temperature for 6 days. Fortunately, it was subse-
quently found that 1a undergoes spontaneous dehydra-
tion to give 1b upon complexation to Pd and Pt. Thus,
there is no need to use pure samples of 1b to make NNP
complexes, as a mixture of 1a and 1b can be employed
conveniently.
Treatment of o-Ph2PC6H4CHO with H2NCH2CH2-
NHCH3 in THF at room temperature for 3 h led to the
formation of a mixture of the carbinolamine phosphine
o-Ph2PC6H4CH(OH)NHCH2CH2NHCH3 (1a ) and the
Compounds 1a and 1b were characterized by 31P, 1H,
and 13C NMR spectroscopy. In particular 1a and 1b (in
CD2Cl2) displayed singlet 31P{1H} signals (in CD2Cl2)
iminophosphine
o-Ph2PC6H4CHdNCH2CH2NHCH3
(NNP; 1b) in about a 3:1 ratio (Scheme 1). Apparently,
dehydration of 1a to give 1b is not complete under the
reaction conditions. Although not very common, there
are reported examples of isolation of carbinolamines
from the reactions of amines with ketones or alde-
hydes.20 Our attempts to complete the dehydration of
1
at -18.6 and -13.3 ppm, respectively. In the H NMR
spectrum (in CD2Cl2), the characteristic CH(OH) proton
signal of 1a was observed at 4.58 ppm, and the char-
acteristic CHdN proton signal of 1b was observed at
8.79 ppm.
Syn th esis of P d a n d P t Com p lexes w ith NNP . A
ligand of the type o-Ph2PC6H4CHdNCH2CH2NHR could
bind to a metal in either a bidentate or a tridentate
mode. To facilitate the characterization of analogous Pt
and Pd complexes with CDNNP (see discussion below),
the reactions of ligand 1 with MCl2(COD) (M ) Pd, Pt)
and [PdCl(η3-C3H5)]2 were investigated.
(18) For work related to PN-mixed donor polydentate ligands, see
for example: (a) Bianchini, C.; Masi, D.; Romerosa, A.; Zanobini, F.;
Peruzzini, M. Organometallics 1999, 18, 2376. (b) Bianchini, C.;
Barbaro, P.; Scapacci, G.; Farnetti, E.; Graziani, M. Organometallics
1998, 17, 3308. (c) Bianchini, C.; Glendenning, L.; Peruzzini, M.;
Purches, G.; Zanobini, F.; Farnetti, E.; Graziani, M.; Nardin, G.
Organometallics 1997, 16, 4403 and references therein. (d) Song, J .
H.; Cho, D. J .; J eon, S. J .; Kim, Y. H.; Kim, T. J .; J eong, J . H. Inorg.
Chem. 1999, 38, 893. (e) Troust, B. M.; Oslob, J . D. J . Am. Chem. Soc.
1999, 121, 3057. (f) Hii, K. K.; Thornton-Pett, M.; J utand, A.; Tooze,
R. P. Organometallics 1999, 18, 1887. (g) Rahmouni, N.; Osborn, J .
A.; De Cian, A.; Fischer, J .; Ezzamarty, A. Organometallics 1998, 17,
2470. (h) Hahn, C.; Vitagliano, A.; Giordano, F.; Taube, R. Organo-
metallics 1998, 17, 2060.
Reactions of ligand 1 with PdCl2(COD) or PdCl2-
(PhCN)2 in dichloromethane produced [PdCl(NNP)]Cl
(2a ) (Scheme 1). Thus, 1a has undergone dehydration
during the reaction. The presence of CHdN in 2a is
(19) Capretta, A.; Maharajh, R. B.; Bell, R. A. Carbohydr. Res. 1995,
267, 49.
1
indicated by the appearances of the H and 13C NMR
(20) (a) Wasserman, H. H.; Baird, M. S. Tetrahedron Lett. 1970,
1729. (b) Bochow, H.; Schneider, W. Chem. Ber. 1975, 108, 3475.
(21) Codina, G.; Caubet. A.; Lo´pez, C.; Moreno, V.; Molins, E. Helv.
Chim. Acta 1999, 82, 1025.
(in CDCl3) signals of CHdN at 9.56 and 166.3 ppm,
respectively. The tridentate nature of the NNP ligand
is supported by the NMR spectroscopic data. In par-

426 Organometallics, Vol. 20, No. 3, 2001
Yang et al.
ticular, the 31P{1H} NMR spectrum (in CDCl3) showed
a singlet at 30.1 ppm; the 1H NMR spectrum (in CDCl3)
showed the coordinated NH signal at 5.84 ppm. For
comparison, the NH signals for [PdCl(H2N(CH2)3NH-
(CH2)3NH2)]+ and [PdCl(H2N(CH2)3NH(CH2)4NH2)]+ were
observed at 5.43 and 6.74 ppm, respectively.21 When the
NH of the NNP ligand is coordinated to Pd, the nitrogen
center becomes stereogenic and the two protons of the
CH2 attached to the NH group in 2a should be in-
equivalent. In the 1H NMR spectrum, the two 1H signals
were observed at 3.34 and 2.57 ppm. Formation of chiral
N centers for complexes of amine ligands with nitrogen
bearing three different substituents have previously
been proposed or implied.16 Formulation of compound
2a as a monocationic complex with one of the chlorides
as the counteranion is supported by the fact that 2a
undergoes a metathesis reaction with NaBPh4 to give
[PdCl(NNP)]BPh4 (2b), which has 31P, 1H, and 13C NMR
data (except the additional signals due to BPh4) similar
to those of 2a .
Sch em e 2
Similarly, 1 reacted with PtCl2(COD) to give [PtCl-
(NNP)]Cl (3a ). The presence of CHdN in 3a has been
1
confirmed by the observation of the H and 13C NMR
(in CDCl3) signals of CHdN at 9.77 and 166.6 ppm,
respectively. Consistent with the structure, 3a under-
goes a metathesis reaction with NaBPh4 to give [PtCl-
(NNP)]BPh4 (3b), which has 31P, 1H and 13C NMR data
(except the additional signals due to BPh4) similar to
those of 3a .
CDNNP (5) can be isolated as a pale yellow solid
P,
Treatment of ligand 1 with [PdCl(η3-C3H5)]2 in dichlo-
(Scheme 2). Compound 5 has been characterized by 31
romethane produced the allyl complex [Pd(η1-C3H5)-
1H, and 13C NMR as well as MS spectroscopy. In
particular, compound 5 (in DMSO) exhibited a singlet
31P{1H} signal at -14.1 ppm. The 31P chemical shift is
very close to that of the analogous iminophoshine ligand
1b. The FAB mass spectrum showed the molecular ion
1
(NNP)]Cl (4a ). In the H NMR spectrum (in CD2Cl2),
the CHdN signal was observed at 8.80 ppm; the allyl
signals were observed at 5.86 (CHd), 4.47 (CH2d), and
2.02 (CH2Pd) ppm. In the 13C NMR spectrum (in CD2-
Cl2), the CHdN signal was observed at 164.3 ppm; the
allyl signals were observed at 110.1 (dCH2), 141.4 (CHd
), and 25.4 (CH2Pd) ppm. The NMR data of the allyl
ligand are inconsistent with those reported for Pd(η3-
C3H5)14,22 but are in agreement with those reported for
Pd(η1-C3H5).23 The chloride in 4a is not coordinated to
Pd, as 4a readily reacted with NaBPh4 to give [Pd(η1-
C3H5)(NNP)]BPh4 (4b), which has 31P, 1H, and 13C NMR
data (except the additional signals of BPh4) similar to
those of 4a . Very few allyl complexes with potentially
tridentate ligands have been reported.13,24 Closely re-
lated examples of such complexes include [Pd(η1-C3H5)(o-
Ph2PC6H4CHdNCH2CH2-2-pyridine)]+ 13 and [Pd(C3H5)-
(2,2′,6′,6′′-terpyridine)]+.24a Interestingly, η1-allyl and η3-
allyl forms are present both in solution and in the solid
state for the latter complex.
1
peak at m/z 1449. In the H and 13C NMR spectra, the
signals of CHdN were observed at 8.84 and 159.8 ppm,
respectively. As indicated by the 31P{1H} NMR spectra,
samples of 5 thus obtained were usually contaminated
with a small amount (<5%) of phosphorus-containing
species having a singlet 31P{1H} signal at -20.6 ppm
(in DMSO). It can be shown that the species does not
interfere with the preparation of Pd and Pt complexes.
We tentatively attribute the phosphorus-containing
species to 6-(o-Ph2PC6H4CH(OH)NHCH2CH2NH)-â-CD,
because the 31P chemical shift of -20.6 ppm is close to
that (-18.6 ppm) of o-Ph2PC6H4CH(OH)NHCH2CH2-
NHCH3.
Syn th esis of P t a n d P d Com p lexes w ith CDNNP .
Reactions of ligand 5 with PdCl2(NCPh)2 in methanol
produced [PdCl(CDNNP)]Cl (6) (Scheme 2). The com-
pound is only slightly soluble in polar solvents such as
MeOH, DMSO, and DMF but is insoluble in organic
solvents such as acetone, dichloromethane, and benzene.
The compound has been characterized by mass spec-
Syn th esis of 6-(o-P h 2P C6H4CHdNCH2CH2NH)-â-
CD (CDNNP ). Stirring a mixture of o-Ph2PC6H4CHO
and 6-H2NCH2CH2NH-â-CD in methanol at room tem-
perature for 24 h produced a yellow solution from which
1
troscopy and 31P, H, and 13C NMR spectroscopy. The
FAB mass spectrum displayed a [PdCl(CDNNP)]+ ion
(22) (a) Yamamoto, T.; Akimoto, M.; Saito, O.; Yamamoto, A.
Organometallics 1986, 5, 1559. (b) Mann, B. E.; Pietropaolo, R.; Shaw,
B. L. J . Chem. Soc., Dalton Trans. 1973, 2390. (c) Lemke, F. R.; Kubiak,
C. P. J . Organomet. Chem. 1989, 373, 391.
(23) (a) De Graaf, W.; Boersma, J .; Van Koten, G. Organometallics
1990, 9, 1479. (b) Bogdanovic, B.; Huckett, S. C.; Wilczok, U.; Rufinska,
A. Angew. Chem., Int. Ed. Engl. 1988, 27, 1513.
(24) (a) Ramdeehul, S.; Barloy, L.; Osborn, J . A.; De Cian, A.; Fisher,
J . Organometallics 1996, 15, 5422 and references therein. (b) Canovese,
L.; Visentin, F.; Chessa, G.; Niero, A.; Uguagliati, P. Inorg. Chim. Acta
1999, 293, 44 and references therein.
peak at m/z 1589. The 1H and 13C NMR spectra
1
exhibited the H and 13C signals of CHdN at 9.26 and
162.5 ppm, respectively. The 31P{1H} NMR spectrum
in CD3OD showed two closely spaced 31P signals at 31.4
and 31.3 ppm. The chemical shifts are very close to those
of the analogous complex [PdCl(NNP)]Cl, confirming
that the two complexes have similar coordination spheres.

Pd and Pt Complexes with a Phosphine Ligand
Organometallics, Vol. 20, No. 3, 2001 427
The observation of two 31P signals for 6 is not surprising.
When the NH of CDNNP is coordinated to Pd, the
nitrogen becomes stereogenic. Because the CD func-
tionality is chiral, two diasteroisomers are therefore
temperature for 3 h to give a red-brown solution. The solvent
was then removed completely under vacuum to give a red-
brown oil. Addition of acetonitrile (30 mL) to the residue
afforded a pale yellow solid, which was collected by filtration,
washed with acetonitrile, and dried under vacuum. Yield: 2.1
g. NMR data indicate that the solid is a mixture of o-Ph2PC6H4-
CH(OH)NHCH2CH2NHCH3 (1a ) and o-Ph2PC6H4-CHdNCH2-
CH2NHCH3 (NNP; 1b) in about a 3:1 ratio. Selected charac-
terization data for 1a are as follows. EI-MS: m/z 361 ([M -
1
expected for 6. However, the difference in the H and
13C chemical shifts of CHdN in the two isomers must
1
be very small, as only one set of H and 13C data were
observed for 6.
1
3]+). 31P{1H} NMR (121.5 MHz, CD2Cl2): δ -18.6 (s). H NMR
The analogous Pt complex [PtCl(CDNNP)]Cl (7) was
produced from the reaction of ligand 5 with PtCl2(COD)
in methanol. Like complex 6, complex 7 in methanol also
showed two closely spaced 31P{1H} signals at 4.59 and
4.52 ppm. Because the chemical shifts are very similar
to those of 3a , it is reasonable to assume that the
complexes 3a and 7 have similar coordination spheres.
Consistent with the structure, the FAB mass spectrum
of 7 displayed a [PtCl(CDNNP)]+ ion peak at m/z 1643;
(300.13 MHz, CD2Cl2): δ 7.68 (m, 1 H, C6H4), 6.93 (m, 1 H,
C6H4), 7.36-7.18 (m, other aromatic signals mixed with 1b),
4.58 (d, J (HH) ) 5.3 Hz, 1 H, CH(OH)), 3.26-3.17 (m, 1 H of
CH2NHCH(OH) and 1 H of CH2NHCH3), 2.98 (m, 1 H, CH2-
NHCH3), 2.33 (m, 1 H, CH2NHCH(OH)), 1.87 (s, 3 H, CH3);
the OH and NH signals are merged with that of water at 1.87
ppm. 13C{1H} NMR (75.5 MHz, CD2Cl2): δ 146.2-128.4 (m,
aromatic signals mixed with 1b), 82.2 (d, J (PC) ) 19.9 Hz,
CH(OH)), 55.9 (s, CH2NHCH(OH)), 45.7 (s, CH2NHCH3), 38.9
(s, CH3). Selected characterization data for 1b are as follows.
EI-MS: m/z 347 ([M + 1]+). 31P{1H} NMR (121.5 MHz, CD2-
1
the H NMR spectrum of 7 showed the CHdN signal at
9.29 ppm.
1
Treatment of ligand 5 with [PdCl(η3-C3H5)]2 in metha-
nol produced the allyl complex [Pd(η1-C3H5)(CDNNP]-
Cl (8). Complex 8 also exists as two isomers, as the
31P{1H} NMR spectrum (in CD3OD) displayed two 31P
signals at 31.6 and 31.5 ppm. The similarity in the 31P
chemical shifts of complexes 4 and 8 suggests that the
coordination sphere of 8 is similar to that of 4. The
Cl2): δ -13.3 (s). H NMR (300.13 MHz, CD2Cl2): δ 8.79 (d,
J (PH) ) 4.3 Hz, 1 H, CHdN), 7.87 (m, 1 H, C6H4), 6.87 (m, 1
H, C6H4), 7.36-7.18 (m, other aromatic signals mixed with 1a ),
3.56 (t, J (HH) ) 5.5 Hz, 2 H, CH2Nd), 2.62 (t, J (HH) ) 5.5
Hz, 2 H, CH2NH), 2.22 (s, 3 H, CH3). 13C{1H} NMR (75.5 MHz,
CD2Cl2): δ 161.3 (d, J (PC) ) 16.8 Hz, CHdN), 146.2-128.4
(m, aromatic signals mixed with 1a ), 61.3 (s, CH2Nd), 52.7
(s, CH2NH), 36.6 (s, CH3).
1
assumption is supported by the mass and H and 13C
[P d Cl(NNP )]Cl (2a ). Meth od 1. A solution of 1 (200 mg,
ca. 0.56 mmol) in dichloromethane (10 mL) was added drop-
wise to a dichloromethane solution (10 mL) of PdCl2(COD) (165
mg, 0.58 mmol) to give a yellow solution. The reaction mixture
was stirred for 1 h at room temperature. The volume of the
reaction mixture was then reduced to ca. 2 mL under vacuum.
Addition of ether (20 mL) to the reaction mixture afforded a
light brown solid. After the mixture was stirred for an
additional 2 h, the solid was collected by filtration, washed
with ether, and dried under vacuum. Yield: 0.27 g, 93%.
Meth od 2. A solution of 1 (250 mg, 0.69 mmol) in 10 mL of
dichloromethane was added to a solution of PdCl2(PhCN)2 (290
mg, 0.74 mmol) in 15 mL of dichloromethane. The mixture
was stirred for 1 h at room temperature. Then the solvent was
removed under vacuum to afford a light brown solid. The solid
was washed with ether and then dried under vacuum. Yield:
0.31 g, 88%. CI-MS: m/z 487 ([PdCl(NNP)]+), 452 ([Pd-
(NNP)]+). 31P{1H} NMR (121.5 MHz, CDCl3): δ 30.1 (s). 1H
NMR (300.13 MHz, CDCl3): δ 9.56 (br, 1 H, CHdN), 8.40 (m,
1 H, C6H4), 7.77 (m, 1 H, C6H4), 7.64-7.42 (m, 11 H, 1 H of
C6H4 and 10 H of PPh2), 7.23 (m, 1 H, C6H4), 5.84 (s, br, 1 H,
NH, disappeared in the presence of D2O), 4.53 (s, br, 2 H,
CH2Nd), 3.34 (s, br, 1 H, CH2NH), 2.70 (t, J (HH) ) J (PH) )
5.0 Hz, 3 H, CH3), 2.57 (s, br, 1 H, CH2NH). 13C{1H} NMR
(75.5 MHz, CDCl3): δ 166.3 (d, J (PC) ) 6.7 Hz CHdN), 140.1-
127.4 (m, PPh2, C6H4), 67.3 (s, CH2Nd), 53.0 (s, CH2NH), 39.5
(s, CH3).
[P d Cl(NNP )]BP h 4 (2b). A solution of NaBPh4 (0.12 g, 0.35
mmol) in methanol (10 mL) was added to a solution of [PdCl-
(NNP)]Cl (150 mg, 0.29 mmol) in methanol (10 mL) to give a
gray precipitate. The solid was collected by filtration, washed
with methanol and water, and dried under vacuum. Yield:
0.17 g, 78%. FAB-MS: m/z 487 ([PdCl(NNP)]+), 452 ([Pd-
(NNP)]+). Anal. Calcd for C46H43BClN2PPd‚H2O: C, 66.93; H,
5.50; N, 3.39. Found: C, 66.65; H, 5.53; N, 3.14. 31P{1H} NMR
(121.5 MHz, DMSO-d6): δ 29.4 (s). 1H NMR (300.13 MHz,
DMSO-d6): δ 9.00 (br, 1 H, CHdN), 8.17 (m, 1 H, C6H4), 8.03
(m, 1 H, C6H4), 7.94 (m, 1 H, C6H4), 7.79-7.64 (m, 10 H, PPh2),
7.49 (m, 1 H, C6H4), 7.30-6.88 (m, 20 H, BPh4), 6.15 (m, 1 H,
NH), 4.34 (m, 1 H, CH2Nd), 4.08 (m, 1 H, CH2Nd), 3.45 (br,
water), 3.10 (m, 1 H, CH2NH), 2.76 (t, J (HH) ) J (PH) ) 5.3
Hz, 3 H, CH3), 2.71 (m, 1 H, CH2NH). 13C{1H} NMR (75.5 MHz,
NMR spectroscopy. For example, the FAB mass spec-
trum displayed the [Pd(η1-C3H5)(CDNNP)]+ ion peak at
1
m/z 1631; the H NMR spectrum (in DMF-d7) showed a
CHdN signal at 9.12 ppm and allyl signals at 5.67
(CHd), 4.22 (CH2d), and 3.10 (CH2Pd) ppm.
In summary, we have prepared the novel cyclodextrin-
functionalized iminophosphine ligand CDNNP and its
Pd and Pt complexes. In the future, we shall study
catalytic reactions using metal complexes with the
phosphine ligand in order to investigate the effects of
the CD substituent on the regio- and stereochemistry
of catalytic reactions.
Exp er im en ta l Section
Unless otherwise stated, all manipulations were carried out
under a nitrogen atmosphere using standard Schlenk tech-
niques. Solvents were distilled under nitrogen from sodium-
benzophenone (ether, THF, benzene) or calcium hydride
(CH2Cl2). The starting material 6-NH2CH2CH2NH-â-CD was
prepared according to a literature method.19 All other reagents
were used as purchased from Aldrich Chemical Co. or Strem.
1H, 13C{1H}, and 31P{1H} NMR spectra were collected on a
1
Bruker ARX-300 or a J EOL EX-400 spectrometer. H and 13C
NMR chemical shifts are relative to TMS, and 31P NMR
chemical shifts are relative to 85% H3PO4. Mass spectra were
recorded on a Finnigan TSQ7000 spectrometer. Microanalyses
were performed by M-H-W Laboratories (Phoenix, AZ). Since
cyclodextrin derivatives have a high affinity for water or other
solvent molecules, it is usually difficult to get satisfactory
analytical data for them. In fact, analytical data for cyclodex-
trin derivatives are often either not reported or have to be
fitted with variable amounts of water or other solvent mol-
ecules in the literature. In our case, it is also necessary to add
some water molecules, as usual, to the formula in order to
match the experimental values.
o-P h 2P C6H4-CH(OH)NHCH2CH2NHCH3 (1a ) a n d o-P h 2-
P C6H4-CHdNCH2CH2NHCH3 (NNP , 1b). A mixture of N-
methylethylenediamine (2.3 mL, 26.2 mmol) and o-Ph2PC6H4-
CHO (2.4 g, 8.3 mmol) in THF (15 mL) was stirred at room

428 Organometallics, Vol. 20, No. 3, 2001
Yang et al.
DMSO-d6): δ 165.0 (d, J (PC) ) 6.7 Hz, CHdN), 163.3 (1:1:1:1
quartet, J (BC) ) 49.2 Hz, ipso BPh4), 138.4-118.8 (m, C6H4,
PPh2, BPh4), 66.4 (s, CH2Nd), 51.0 (s, CH2NH), 37.6 (d, J (PC)
) 3.0 Hz, CH3).
1 H, NH), 4.09 (s, br, 2 H, CH2Nd), 3.14 (s, br, 2 H, CH2NH),
3.02 (m, 3 H, CH3), 2.23 (m, 2 H, CH2Pd). 13C{1H} NMR (75.5
MHz, acetone-d6): δ 165.5 (d, J (PC) ) 3.8 Hz, CHdN), 165.2
(1:1:1:1 quartet, J (BC) ) 49.2 Hz, ipso BPh4), 141.1 (s, HCd
CH2), 139.4 (d, J (PC) ) 9.0 Hz, C6H4), 137.4-126.4 (m, C6H4,
PPh2), 110.0 (s, HCdCH2), 62.9 (s, CH2Nd), 53.8 (s, CH2NH),
38.2 (s, CH3), 25.1 (s, CH2Pd).
CDNNP (5). o-Ph2PC6H4CHO (0.13 g, 0.45 mmol) was
added to a suspension of 6-NH2CH2CH2NH-â-CD (0.50 g, 0.42
mmol) in 50 mL of methanol. The mixture was stirred for 24
h at room temperature to afford a yellow solution. The solvent
was then removed under vacuum to give a pale yellow solid,
which was washed with acetone and dried under vacuum.
Yield: 0.52 g, 86%. FAB-MS: m/z 1449 (M+). 31P{1H} NMR
(121.5 MHz, DMSO-d6): δ -14.1 (s, predominant, CDNNP),
-20.6 (s, minor, could be due to 6-(o-Ph2PC6H4CH(OH)NHCH2-
CH2NH)-â-CD). 1H NMR (300.13 MHz, CD3OD): δ 9.51 (d,
J (PH) ) 4.1 Hz, 1 H, CHdN), 8.09-7.41 (m, 14 H, C6H4, PPh2),
5.16 (s, 7 H, H-1), 5.0 (br, OH of CD and methanol), 3.95-2.8
(m, other protons). 13C{1H} NMR (100.40 MHz, DMSO-d6): δ
160.1 (d, J (PC) ) 16.4 Hz, CHdN), 139.4-124.5 (m, C6H4,
PPh2), 102.3 (br, C-1), 83.5-81.9 (m, C-4), 73.5-68.9 (m, C-2,
C-3, C-5), 60.9 (s, CH2Nd), 60.3 (m, C-6), 50.9 (s, CH2NH, 46.7
(CH2NH).
[P tCl(NNP )]Cl (3a ). A solution of 1 (170 mg, 0.47 mmol)
in 10 mL of dichloromethane was added to a dichloromethane
solution (10 mL) of PtCl2(COD) (184 mg, 0.49 mmol) to give a
greenish yellow solution. The mixture was stirred for 1 h at
room temperature. The volume of the reaction mixture was
then reduced to ca. 5 mL under vacuum. Addition of ether (40
mL) to the reaction flask afforded a yellow solid. After the
mixture was stirred for another 2 h, the solid was collected by
filtration, washed with ether and dried under vacuum. Yield:
0.25 g, 86%. CI-MS: m/z 575 ([PtCl(NNP)]+), 541 ([Pt(NNP)]+).
31P{1H} NMR (121.5 MHz, CDCl3): δ 4.1 (s with Pt satellites,
J (PtP) ) 3344 Hz). 1H NMR (300.13 MHz, CDCl3): δ 9.77 (br,
1 H, CHdN), 8.42-7.33 (m, 14 H, C6H4, PPh2), 6.96 (s, br, 1
H, NH), 4.50 (br, 2 H, CH2Nd), 3.28 (br, 1 H, CH2NH), 2.82
(t, J (HH) ) 4.5 Hz, 3 H, CH3), 2.56 (m, br, 1 H, CH2NH). 13C-
{1H} NMR (75.5 MHz, CDCl3): δ 163.6 (d, J (PC) ) 7.6 Hz,
CHdN), 139.4-127.4 (m, C6H4, PPh2), 68.4 (s, CH2Nd), 53.8
(s, CH2NH), 39.5 (s, CH3).
[P tCl(NNP )]BP h 4 (3b). A solution of NaBPh4 (0.10 g, 0.29
mmol) in methanol (10 mL) was added to a solution of [PtCl-
(NNP)]Cl (150 mg, 0.26 mmol) in methanol (10 mL) to give a
yellow precipitate. The solid was collected by filtration, washed
with methanol and water, and then dried under vacuum.
Yield: 0.17 g, 76%. FAB-MS: m/z 575 ([PtCl(NNP)]+), 541 ([Pt-
(NNP)]+). Anal. Calcd for C46H43BClN2PPt: C, 61.65; H, 4.84;
N, 3.13. Found: C, 61.49; H, 4.86; N, 2.94. 31P{1H} (121.5 MHz,
[P d Cl(CDNNP )]Cl (6). A solution of CDNNP (200 mg, 0.14
mmol) in 30 mL of methanol was added dropwise to a solution
of PdCl2(PhCN)2 (53 mg, 0.14 mmol) in 10 mL of methanol. A
brown precipitate was formed immediately. The reaction
mixture was stirred for 1 h at room temperature. The solvent
was then removed under vacuum to afford a brown solid, which
was washed with acetone, ether, and dichloromethane and
dried under vacuum. Yield: 0.21 g, 91%. The compound could
also be prepared from the reaction of PdCl2(COD) with
CDNNP. FAB-MS: m/z 1589 ([PdCl(CDNNP)]+), 1553 ([Pd-
(CDNNP)]+). Anal. Calcd for C63H89Cl2N2O34PPd‚9H2O: C,
42.30; H, 6.03; N, 1.57. Found: C, 41.66; H, 5.62; N, 1.34. 31P-
1
DMSO-d6): δ 3.9 (s with Pt satellites, J (PtP) ) 3306 Hz). H
NMR (300.13 MHz, DMSO-d6): δ 9.29 (br, 1 H, CHdN), 8.23-
7.46 (m, 14 H, C6H4, PPh2), 7.30-6.86 (m, 20 H, BPh4), 4.47
(m, 1 H, CH2Nd), 4.21 (m, 1 H, CH2Nd), 3.06 (m, 1 H, CH2N),
2.76 (t, J (HH) ) 5.3 Hz, 3 H, CH3), 2.71 (m, 1 H, CH2NH), the
NH signal is merged with that of water at 3.46 ppm. 13C{1H}
NMR (75.5 MHz, DMSO-d6): δ 165.0 (d, J (PC) ) 6.7 Hz, CHd
N), 163.3 (1:1:1:1 quartet, J (BC) ) 49.2 Hz, ipso-BPh4), 138.4-
121.5 (m, C6H4, PPh2, BPh4), 67.5 (s, CH2Nd), 51.8 (s, CH2NH),
37.9 (s, CH3).
[P d (η1-C3H5)(NNP )]Cl (4a ). A solution of 1 (180 mg, 0.50
mmol) in 10 mL of dichloromethane was added to a solution
of [PdCl(η3-C3H5)]2 (95 mg, 0.26 mmol of Pd) in 10 mL of
dichloromethane to give a greenish yellow solution. The
mixture was stirred for 1 h at room temperature, and then
the solvent was removed under vacuum to afford a yellow solid.
The residue was washed with ether and dried under vacuum.
Yield: 0.17 g, 94%. FAB-MS: m/z 493 ([Pd(C3H5)(NNP)]+), 452
([Pd(NNP]+). 31P{1H} NMR (121.5 MHz, CDCl3): δ 34.7 (s).
1H NMR (300.13 MHz, CD2Cl2): δ 8.80 (br, 1 H, CHdN), 7.86
(m, 1 H, C6H4), 7.66 (m, 2 H, C6H4), 7.55-7.37 (m, 12 H, C6H4,
PPh2), 6.00 (s, br, 1 H, NH), 5.86 (m, 1 H, CH2dCH), 4.47 (m,
2 H, CH2dCH), 4.09 (br, 2 H, CH2Nd), 2.97 (br, 2 H, CH2-
NH), 2.69 (m, 3 H, CH3), 2.02 (m, 2 H, CH2Pd). 13C{1H} NMR
(75.5 MHz, CD2Cl2): δ 164.3 (d, J (PC) ) 3.8 Hz, CHdN), 141.4
(s, HCdCH2), 138.7-128.6 (m, C6H4, PPh2), 110.1 (s, HCd
CH2), 62.9 (s, CH2Nd), 53.8 (s, CH2NH), 38.3 (s, CH3), 25.4 (s,
CH2Pd).
[P d (η1-C3H5)(NNP )]BP h 4 (4b). A solution of NaBPh4 (80
mg, 0.23 mmol) in methanol (10 mL) was added to a solution
of [Pd(η1-C3H5)(NNP)]Cl (100 mg, 0.19 mmol) in methanol (10
mL) to give a yellow precipitate. The solid was then collected
by filtration, washed with methanol and water, and dried
under vacuum. Yield: 0.14 g, 94%. Anal. Calcd for C49H48BN2-
PPd‚H2O: C, 70.81; H, 6.06; N, 3.37. Found: C, 70.89; H, 5.94;
N, 3.50. FAB-MS: m/z 493 ([Pd(C3H5)(NNP)]+); 452 ([Pd-
(NNP)]+). 31P{1H}NMR (121.5 MHz, acetone-d6): δ 35.4. 1H
NMR (300.13 MHz, acetone-d6): δ 8.70 (br, 1 H, CHdN), 8.04-
7.71 (m, 14 H, C6H4, PPh2), 7.52-6.90 (m, 24 H, BPh4), 5.94
(m, 1 H, CH2dCH), 4.83-4.71 (m, 2 H, CH2dCH), 4.52 (s, br,
1
{1H} NMR (121.5 MHz, CD3OD): δ 31.3 (s), 31.4 (s). H NMR
(300.13 MHz, DMF-d7): δ 9.07 (br, 1 H, CHdN), 8.29-7.48
(m, 14 H, C6H4, PPh2), 5.87 (m, br, OH), 4.97 (m, 7 H, H-1),
4.8-2.7 (m, other protons); 13C{1H} (100.40 MHz, DMSO-d6):
δ 164.6 (d, J (PC) ) 7.0 Hz, CHdN), 145.4-125.4 (m, C6H4,
PPh2), 101.9 (C-1), 81.7 (C-4), 73.1-72.6 (C-2, C-3, C-5), 66.1
(CH2Nd), 60.1 (C-6), 51.0 (CH2N), 47.1 (CH2NH).
[P t(CDNNP )Cl]Cl (7). A mixture of PtCl2(COD) (0.10 g,
0.27 mmol) and CDNNP (0.38 g, 0.27 mmol) in methanol (50
mL) was stirred at room temperature for 3 h to give a pale
yellow solution. The solvent was then removed under vacuum
to afford a white solid, which was collected by filtration,
washed with acetone, ether, and dichloromethane, and dried
under vacuum. Yield: 0.20 g, 45%. FAB-MS: 1679 ([PtCl-
(CDNNP)]+), 1643 ([Pt(CDNNP)]+). Anal. Calcd for C63H89
-
Cl2N2O34PPt‚9H2O: C, 40.30; H, 5.78; N, 1.49. Found: C,
39.64; H, 5.26; N, 1.40. 31P{1H} NMR (121.5 MHz, CD3OD): δ
4.59(s), 4.52 (s with Pt satellites, J (Pt-P) ) 3389 Hz). 1H NMR
(300.13 MHz, CD3OD): δ 9.28 (d, J (PH) ) 3.6 Hz, 1 H, Nd
CH), 8.09-7.66 (m, 14 H, C6H4, PPh2), 5.39 (m, 7 H, H-1), 4.7-
3.0 (m, other protons).
[P d (η1-C3H5)(CDNNP )]Cl (8). A mixture of [PdCl(η3-
C3H5)]2 (51 mg, 0.14 mmol of Pd) and CDNNP (0.20 g, 0.14
mmol) in 20 mL of methanol was stirred for 1 h at room
temperature. The solvent was then evaporated to dryness
under vacuum. A yellowish solid was obtained when 50 mL of
acetone was added to the reaction flask. The solid was collected
by filtration, washed with acetone and dichloromethane, and
then dried under vacuum. Yield: 0.21 g, 92%. FAB-MS: m/z
1631 ([Pd(C3H5)(CDNNP)]+), 1554 ([Pd(CDNNP)]+). Anal.
Calcd for C66H94ClN2O34PPd‚9H2O: C, 44.18; H, 6.29; N, 1.56.
Found: C, 44.03; H, 5.68; N, 1.83. 31P{1H} NMR (121.5 MHz,
1
CD3OD): δ 31.6 (s), 31.5 (s). H NMR (300.13 MHz, DMF-d7):
δ 8.90 (br, 1 H, NdCH), 8.28-7.40 (m, 14 H, C6H4, PPh2), 5.67
(m, 1 H, CHdCH2), 5.25-5.16 (m, 7 H, H-1), 4.75 (br, OH and

Pd and Pt Complexes with a Phosphine Ligand
Organometallics, Vol. 20, No. 3, 2001 429
NH), 4.22 (m, 2 H, CHdCH2), 3.10 (m, 2 H, CH2Pd), 4.09-3.0
(m, other protons). The 1H signals of the allyl group were
assigned on the basis of a H-H COSY experiment. 13C{1H}
NMR (100.40 MHz, DMF-d7): δ 164.2 (s, CHdN), 140.6 (s,
HCdCH2), 138.2-123.8 (m, C6H4, PPh2), 108.2 (s, HCdCH2 ),
102.8-102.0 (m, C-1), 84.4-81.7 (m, C-4), 73.8-72.7 (m, C-2,
C-3, C5), 66.6 (s, CH2Nd), 61.8-60.6 (m, C-6), 50.0 (CH2NH),
48.3 (CH2NH), 25.0 (s, CH2Pd).
Ack n ow led gm en t. We acknowledge financial sup-
port from the Hong Kong Research Grants Council.
OM000634E