Synthesis and Structure of Novel Iridium(I) Complexes Containing η4-1,6-Diene and Diphosphine Ligands: Remarkable Effect of Ligand Bite Angle upon Ligand Dissociation

Article abstract of DOI:10.1021/om034282y

The treatment of [IrCl(cod)]₂ with a bidentate diphosphine ligand, bis(diphenylphosphino)-methane (dppm), and 1,6-dienes such as dimethyl 2,2-diallylmalonate (1) and diallyl ether (2) produces a ligand replacement reaction to afford novel iridium(I) complexes bearing η⁴-1,6- diene ligands, IrCl(dppm)[η⁴-CH₂=CHCH ₂C(CO₂Me)₂CH₂CH=CH₂] (3) and IrCl(dppm)-(η⁴-CH₂=CHCH₂OCH ₂CH=CH₂) (4), respectively, in excellent yields. The molecular structure of the diallyl ether complex 4, which has been unequivocally determined by a single-crystal X-ray diffraction study, discloses that 2 coordinates to the iridium metal in an η⁴ fashion with a distorted-trigonal-bipyramidal geometry. In a similar manner, 1,2-bis(diphenylphosphino)ethane (dppe) is also a tolerant diphosphine ligand, and the corresponding η⁴-1,6-diene complexes IrCl(dppe) [η⁴-CH₂=CHCH₂C(CO₂Me) ₂CH₂CH=CH₂] (5) and IrCl(dppe) (η⁴-CH₂=CHCH₂OCH₂CH=CH ₂) (6) have been isolated in high yields. On the other hand, diphosphine ligands with a carbon linkage longer than that in dppe, such as 1,3-bis(diphenylphosphino)propane (dppp) and 1,4-bis(diphenylphosphino)butane (dppb), never activate the cod ligand, resulting in no exchange with the 1,6-dienes. Instead of the expected η⁴-1,6-diene complexes, IrCl(cod)(dppp) (7) and IrCl(cod)(dppb) (8) are exclusively formed. The molecular structure of 8 is also confirmed by an X-ray crystallographic analysis. The coordination geometry of 8 is consistent with a distorted square pyramid. The reactivity toward the ligand displacement depends on the natural bite angle of the bidentate phosphine ligands.

Full text of DOI:10.1021/om034282y

1730
Organometallics 2004, 23, 1730-1737
Syn th esis a n d Str u ctu r e of Novel Ir id iu m (I) Com p lexes
Con ta in in g η4-1,6-Dien e a n d Dip h osp h in e Liga n d s:
Rem a r k a ble Effect of Liga n d Bite An gle u p on Liga n d
Dissocia tion
Tatsuya Makino,† Yoshihiko Yamamoto,‡ and Kenji Itoh*,†
Department of Molecular Design and Engineering and Department of Applied Chemistry,
Graduate School of Engineering, Nagoya University, Chikusa, Nagoya 464-8603, J apan
Received November 6, 2003
The treatment of [IrCl(cod)]2 with a bidentate diphosphine ligand, bis(diphenylphosphino)-
methane (dppm), and 1,6-dienes such as dimethyl 2,2-diallylmalonate (1) and diallyl ether
(2) produces a ligand replacement reaction to afford novel iridium(I) complexes bearing η4-
1,6-diene ligands, IrCl(dppm)[η4-CH2dCHCH2C(CO2Me)2CH2CHdCH2] (3) and IrCl(dppm)-
(η4-CH2dCHCH2OCH2CHdCH2) (4), respectively, in excellent yields. The molecular structure
of the diallyl ether complex 4, which has been unequivocally determined by a single-crystal
X-ray diffraction study, discloses that 2 coordinates to the iridium metal in an η4 fashion
with a distorted-trigonal-bipyramidal geometry. In a similar manner, 1,2-bis(diphenylphos-
phino)ethane (dppe) is also a tolerant diphosphine ligand, and the corresponding η4-1,6-
diene complexes IrCl(dppe)[η4-CH2dCHCH2C(CO2Me)2CH2CHdCH2] (5) and IrCl(dppe)(η4-
CH2dCHCH2OCH2CHdCH2) (6) have been isolated in high yields. On the other hand,
diphosphine ligands with a carbon linkage longer than that in dppe, such as 1,3-bis(diphen-
ylphosphino)propane (dppp) and 1,4-bis(diphenylphosphino)butane (dppb), never activate
the cod ligand, resulting in no exchange with the 1,6-dienes. Instead of the expected η4-1,6-
diene complexes, IrCl(cod)(dppp) (7) and IrCl(cod)(dppb) (8) are exclusively formed. The
molecular structure of 8 is also confirmed by an X-ray crystallographic analysis. The co-
ordination geometry of 8 is consistent with a distorted square pyramid. The reactivity toward
the ligand displacement depends on the natural bite angle of the bidentate phosphine
ligands.
In tr od u ction
and all of them are claimed to have planar structures.3-6
Among them, the most important one is the Karstedt
complex [Pt(η4-dvds)]2(µ-η2-η2-dvds) (dvds ) 1,3-divinyl-
1,1,3,3-tetramethyldisiloxane), which is recognized as
The chemistry of transition-metal complexes bearing
nonconjugated cyclic diene ligands such as 1,5-cyclooc-
tadiene (cod) and 2,5-norbornadiene (nbd) has been
extensively investigated, because such complexes could
be readily prepared and handled without special care.
The facile replacement of these ligands to with others
such as phosphines and amines makes them versatile
materials for the preparation of a wide range of transi-
tion-metal complexes.1 In this regard, these complexes
are also known as extremely useful catalyst precursors
and have been employed in a number of transition-
metal-catalyzed reactions.2 On the other hand, noncon-
jugated acyclic dienes, such as 1,6-heptadiene and
diallyl ether, have received less attention as a support-
ing ligand of transition metals. There have been only a
limited number of complexes of the group 10 elements,
(3) For nickel complexes, see: (a) Yamamoto, T.; Ishizu, J .; Yama-
moto, A. J . Am. Chem. Soc. 1981, 103, 6863-6869. (b) Proft, B.;
Po¨rschke, K.-R.; Lutz, F.; Kru¨ger, C. Chem. Ber. 1991, 124, 2667-
2675. (c) Pluta, C.; Po¨rschke, K.-R.; Gabor, B.; Mynott, R. Chem. Ber.
1994, 127, 489-500. (d) Rosenthal, U.; Pulst, S.; Kempe, R.; Po¨rschke,
K.-R.; Goddard, R.; Proft, B. Tetrahedron 1998, 54, 1277-1287. (e)
Hitchcock, P. B.; Lappert, M. F.; MacBeath, C.; Scott, F. P. E.;
Warhurst, N. J . W. J . Organomet. Chem. 1997, 528, 185-190.
(4) For palladium complexes, see: (a) Yamamoto, T.; Akimoto, M.;
Saito, O.; Yamamoto, A. Organometallics 1986, 5, 1559-1567. (b)
Krause, J .; Haack, K.-J .; Cestaric, G.; Goddard, R.; Po¨rschke, K.-R.
Chem. Commun. 1998, 1291-1292. (c) Krause, J .; Cestaric, G.; Haack,
K.-J .; Seevogel, K.; Storm, W.; Po¨rschke, K.-R. J . Am. Chem. Soc. 1999,
121, 9807-9823.
(5) For platinum complexes, see: (a) J ones, R. J . Chem. Soc. A 1969,
2477-2480. (b) Benedetti, E.; de Renzi, A.; Panunzi, A.; Pedone, C. J .
Organomet. Chem. 1972, 39, 403-412. (c) Hubert, J .; Beauchamp, A.
L.; Theophanides, T. Can. J . Chem. 1973, 51, 604-608. (d) Grigg, R.;
Malone, J . F.; Mitchell, T. R. B.; Ramasubbu, A.; Scott, R. M. J . Chem.
Soc., Perkin Trans. 1 1984, 1745-1754. (e) Chandra, G.; Lo, P. Y.;
Hitchcock, P. B.; Lappert, M. F. Organometallics 1987, 6, 191-192.
(f) Hitchcock, P. B.; Lappert, M. F.; Warhurst, N. J . W. Angew. Chem.,
Int. Ed. Engl. 1991, 30, 438-440. (g) Lappert, M. F.; Scott, F. P. A. J .
Organomet. Chem. 1995, 492, C11-C13. (h) Bassindale, A. R.; Brown,
S. S. D.; Lo, P. Organometallics 1994, 13, 738-740. See also refs 3e
and 4b,c.
* To whom correspondence should be addressed. E-mail: itohk@
apchem.nagoya-u.ac.jp. Tel: +81-52-789-5112. Fax: +81-52-789-3205.
† Department of Molecular Design and Engineering.
‡ Department of Applied Chemistry.
(1) (a) Comprehensive Organometallic Chemistry; Wilkinson, G.,
Stone, F. G. A., Abel, E. W., Eds.; Pergamon: Oxford, U.K., 1982. (b)
Comprehensive Organometallic Chemistry II; Abel, E. W., Stone, F.
G. A., Wilkinson, G., Eds.; Pergamon: Oxford, U.K., 1995.
(2) Hegedus, L. S. Transition Metals in the Synthesis of Complex
Organic Molecules, 2nd ed.; University Science Books: Sausalito, CA,
1999.
(6) Grigg et al. reported the preparation and characterization of the
square-planar rhodium(I) complex Rh(acac)(η4-1,6-diene); see: Grigg,
R.; Kongkathip, B.; King, T. J . J . Chem. Soc., Dalton Trans. 1978, 333-
339.
10.1021/om034282y CCC: $27.50 © 2004 American Chemical Society
Publication on Web 03/16/2004

Ir(I) Complexes with Diene and Diphosphine Ligands
Organometallics, Vol. 23, No. 8, 2004 1731
Sch em e 1
an efficient catalyst for the hydrosilylation of alkenes,
including industrial processes.7
In sharp contrast to the formation of the η4-1,6-diene
complexes, the reaction of low-valent early transition
metals such as titanium,8 zirconium,9 and tantalum
species10 with 1,n-dienes furnishes the corresponding
metallabicyclic complexes through an oxidative cycliza-
tion process. In particular, bicyclic zirconacycloalkanes
have been ingeniously applied to the efficient construc-
tion of ring systems.11 Several nickel complexes also
brought about oxidative cyclization to afford nickelacy-
cloalkanes.12
Moreover, the reaction of transition-metal complexes
with nonconjugated acyclic dienes has already become
a very important process not only in organometallic
chemistry but also in synthetic organic chemistry, as a
result of the significant development of the transition-
metal-catalyzed carbocyclization reactions of 1,n-dienes
over the past decade.13 For example, the catalytic
cycloisomerizations of 1,n-dienes, which have been
recognized as atom-economical and environmentally
benign synthetic processes, have been eagerly investi-
gated with a variety of transition-metal complexes (Sc,14
Ti,8c,15 Zr,16 Ta,10a,b Ru,17 Rh,5d,18 Ni,19 and Pd20). In
several cases of such catalyses, the η4-1,n-diene com-
plexes and bicyclic metallacycloalkanes may behave as
key intermediates.21 Therefore, further elucidation of
the interaction of transition-metal complexes with non-
conjugated acyclic dienes should be undertaken in more
detail.
Herein, we now report that the reaction of the
iridium(I) complex [IrCl(cod)]2 with bidentate diphos-
phine ligands and 1,6-dienes such as dimethyl 2,2-
diallylmalonate and diallyl ether smoothly provided the
displacement of the cod ligand to furnish the novel
iridium(I) η4-1,6-diene diphosphine complexes. It is
noteworthy that diphosphines with a longer linkage
inhibit the exchange of the cod ligand. In such cases,
the corresponding iridium(I) cod diphosphine complexes
are exclusively formed. The structural aspects of the two
representatives are also discussed.
(7) (a) Willing, D. N. U.S. Patent 3,419,593, 1968. (b) Karstedt, B.
D. U.S. Patent 3,775.452, 1973.
(8) (a) McDermott, J . X.; Wilson, M. E.; Whitesides, G. M. J . Am.
Chem. Soc. 1976, 98, 6529-6536. (b) Grubbs, R. H.; Miyashita, A. J .
Chem. Soc., Chem. Commun. 1977, 864-865. (c) Thorn, M. G.; Hill, J .
E.; Waratuke, S. A.; J ohnson, E. S.; Franwick, P. E.; Rothwell, I. P. J .
Am. Chem. Soc. 1997, 119, 8630-8641.
(9) (a) Gell, K. I.; Schwartz, J . J . Chem. Soc., Chem. Commun. 1979,
244-246. (b) Gell, K. I.; Schwartz, J . J . Am. Chem. Soc. 1981, 103,
2687-2695. (c) Rousset, C. J .; Swanson, D. R.; Lamaty, F.; Negishi,
E. Tetrahedron Lett. 1989, 30, 5105-5108. (d) Negishi, E.; Maye, J .
P.; Choueiry, D. Tetrahedron 1995, 51, 4447-4462. (e) Davis, J . M.;
Whitby, R. J .; J axa-Chamiec, A. Tetrahedron Lett. 1992, 33, 5655-
5658. (f) Taber, D. F.; Louey, J . P.; Wang, Y.; Nugent, W. A.; Dixon, D.
A.; Harlow, R. L. J . Am. Chem. Soc. 1994, 116, 9457-9463.
(10) (a) McLain, S. J .; Schrock, R. R. J . Am. Chem. Soc. 1978, 100,
1315-1317. (b) Smith, G.; McLain, S. J .; Schrock, R. R. J . Organomet.
Chem. 1980, 202, 269-277. (c) Churchill, M. R.; Youngs, W. J . Inorg.
Chem. 1980, 19, 3106-3112.
(11) For leading papers, see: (a) Nugent, W. A.; Taber, D. F. J . Am.
Chem. Soc. 1989, 111, 6435-6437. (b) Akita, M.; Yasuda, H.; Yama-
moto, H.; Nakamura, A. Polyhedron 1991, 10, 1-9. (c) Knight, K. S.;
Waymouth, R. M. J . Am. Chem. Soc. 1991, 113, 6268-6270. (d)
Wischmeyer, U.; Knight, K. S.; Waymouth, R. M. Tetrahedron Lett.
1992, 114, 7735-7738. (e) Knight, K. S.; Wang, D.; Waymouth, R. M.;
Ziller, J . J . Am. Chem. Soc. 1994, 116, 1845-1854. (f) Mori, M.; Uesaka,
N.; Shibasaki, M. J . Org. Chem. 1992, 57, 3519-3521. (g) Houri, A.
F.; Didiuk, M. T.; Xu, Z.; Horan, N. R.; Hoveyda, A. H. J . Am. Chem.
Soc. 1993, 115, 6614-6624. (h) Liu, Y.; Shen, B.; Kotora, M.; Nakajima,
K.; Takahashi, T. J . Org. Chem. 2002, 67, 7019-7028 and references
therein.
Resu lts a n d Discu ssion
To a dichloromethane solution of [IrCl(cod)]2 and bis-
(diphenylphosphino)methane (dppm) was added 3 equiv
of dimethyl 2,2-diallylmalonate (1), and the resultant
yellow mixture was stirred for 3 h at room temperature
to afford the novel 1,6-diene complex 3 after recrystal-
lization from dichloromethane/n-hexane as pale yellow-
green solids in 92% yield (Scheme 1). Remarkably, this
product is air-stable even in solution for several days.
The IR spectrum of complex 3, which exhibited a very
strong absorption at 1739 cm-1, apparently indicates
that the ester moiety remained intact. The 1H NMR
spectrum of 3 showed two characteristic peaks corre-
(18) (a) Bright, A.; Molone, J . F.; Nicholson, J . K.; Powell, J .; Shaw,
B. L. J . Chem. Soc., Chem. Commun. 1971, 712-713. (b) Schmitz, E.;
Urban, R.; Heuck, U.; Zimmermann, G.; Gru¨ndemann, E. J . Prakt.
Chem. 1976, 318, 185-192. (c) Schmitz, E.; Heuck, U.; Habisch, D. J .
Prakt. Chem. 1976, 318, 471-478. (d) Grigg, R.; Mitchell, T. R. B.;
Ramasubbu, A. J . Chem. Soc., Chem. Commun. 1980, 27-28.
(19) (a) Bodoganovic, B. Adv. Organomet. Chem. 1979, 17, 105-140.
(b) Behr, A.; Freudenberg, U.; Keim, W. J . Mol. Catal. 1986, 35, 9-17.
(c) Radetich, B. RajanBabu, T. V. J . Am. Chem. Soc. 1998, 120, 8007-
8008. (d) Walther, D.; Do¨hler, T.; Heubach, K.; Klobes, O.; Schweder,
B.; Go¨rls, H. Z. Anorg. Allg. Chem. 1999, 625, 923-932.
(20) (a) Grigg, R.; Mitchell, T. R. B.; Ramasubbu, A. J . Chem. Soc.,
Chem. Commun. 1979, 669-670. (b) Heumann, A.; Moukhliss, M.
Synlett 1998, 1211-1212. (c) Widenhoefer, R. A.; Perch, N. S. Org.
Lett. 1999, 1, 1103-1105. (d) Kisanga, P.; Widenhoefer, R. A. J . Am.
Chem. Soc. 2000, 122, 10017-10026. (e) Kisanga, P.; Goj, L. A.;
Widenhoefer, R. A. J . Org. Chem. 2001, 66, 635-637. (f) Goj, L. A.;
Widenhoefer, R. A. J . Am. Chem. Soc. 2001, 123, 11133-11147. (g)
Bray, K. L.; Fairlamb, I. J . S.; Lloyd-J ones, G. C. Chem. Commun.
2001, 187-188. (h) Bray, K. L.; Charmant, J . P. H.; Fairlamb, I. J . S.;
Lloyd-J ones, G. C. Chem. Eur. J . 2001, 7, 4205-4215. (i) Oh, C. H.;
Kim, J . D.; Han, J . W. Chem. Lett. 2001, 1290-1291. See also refs 5d,
18b,c, and 19c.
(12) Grubbs, R. H.; Miyashita, A. J . Organomet. Chem. 1978, 161,
371-380.
(13) (a) Ojima, I.; Tzamarioudaki, M.; Li, Z.; Donovan, R. Chem. Rev.
1996, 96, 635-662. (b) Trost, B. M.; Krische, M. J . Synlett 1998, 1-16.
(c) Widenhoefer, R. A. Acc. Chem. Res. 2002, 35, 905-913.
(14) (a) Bunel, E. E.; Burger, B. J .; Bercaw, J . E. J . Am. Chem. Soc.
1988, 110, 976-978. (b) Piers, W. E.; Shapiro, P. J .; Bunel, E. E.;
Bercaw, J . E. Synlett 1990, 74-84. (c) Piers, W. E.; Bercaw, J . E. J .
Am. Chem. Soc. 1990, 112, 9406-9407.
(15) (a) Akita, M.; Yasuda, H.; Nagasuna, K.; Nakamura, A. Bull.
Chem. Soc. J pn. 1983, 56, 554-558. (b) Lehmkuhl, H.; Tsien, Y.-L.
Chem. Ber. 1983, 116, 2437-2446. (c) Okamoto, S.; Livinghouse, T. J .
Am. Chem. Soc. 2000, 122, 1223-1224. (d) Okamoto, S.; Livinghouse,
T. Organometallics 2000, 19, 1449-1451.
(16) (a) Christoffers, J .; Bergman, R. G. J . Am. Chem. Soc. 1996,
118, 4715-4716. (b) Thiele, S.; Erker, G. Chem. Ber./ Recl. 1997, 130,
201-207. (c) Bazan, G. C.; Rodriguez, G.; Ashe, A. J ., III; Al-Ahmad,
S.; Kampf, J . W. Organometallics 1997, 16, 2492-2494. (d) Schweder,
B.; Walther, D.; Do¨hler, T.; Klobes, O.; Go¨rls, H. J . Prakt. Chem. 1999,
341, 736-747.
(17) (a) Yamamoto, Y.; Ohkoshi, N.; Itoh, K. J . Org. Chem. 1999,
64, 2178-2179. (b) Yamamoto, Y.; Nakagai, Y.; Ohkoshi, N.; Itoh, K.
J . Am. Chem. Soc. 2001, 123, 6372-6380.
(21) See refs 5d, 8c, 10a,b, 15c,d, and 17.

1732 Organometallics, Vol. 23, No. 8, 2004
Makino et al.
sponding to methoxy groups in 1 at δ 3.65 (s) and 3.89
(s) ppm in chloroform-d. Signals for the coordinated
olefinic protons were observed at higher field, δ 2.24 (dd,
J HH ) 7.5 Hz, J PH ) 7.5 Hz), 2.45-2.49 (m), and 3.52-
3.61 (m) ppm, relative to the uncoordinated ones. The
appearance of only three peaks corresponding to olefinic
protons implies that this complex has a highly sym-
metrical structure. The signal for the methylene protons
of dppm appeared at δ 4.65 (dd, J PH ) 9.0, 11.0 Hz) ppm,
which shifted to a lower field than that of the free dppm
at δ 2.80 (s) ppm. Similarly, the 13C{1H} NMR spectrum
also indicated the structural symmetry of 1, except for
the two ester moieties. The 31P{1H} NMR spectrum
showed two signals at higher field, δ -69.9 (d, J PP
)
45.7 Hz) and -56.8 (d, J PP ) 45.7 Hz) ppm, suggesting
that the two phosphorus atoms were not equivalent to
each other. These spectral features of complex 3 support
that the geometry of 3 is a trigonal bipyramid rather
than a square pyramid. The axial positions are occupied
by one of the phosphorus atoms of dppm and the
chlorine atom, whereas the two olefinic π-bonds of 1 and
the other phosphorus atom are present at equatorial
positions. Any attempts to obtain crystals of 3 suitable
for X-ray structural analysis were unsuccessful. Obvi-
ously, the formation of 3 stems from the displacement
of the cod ligand in the mononuclear IrCl(cod)(dppm)
intermediate initially formed in situ. In contrast, the
analogous dinuclear iridium(I) complex [IrCl(coe)2]2 (coe
) cyclooctene) did not lead to any expected complex 4
but an uncharacterized dark brown solid, presumably
by way of [IrCl(diphosphine)]2, under identical condi-
tions. This result proved that only a mononuclear
complex such as IrCl(cod)(dppm) plays a key role in this
substitution of the cod ligand (vide infra).
Diallyl ether (2) also induces the ligand displacement
reaction to produce 4 from the reaction of [IrCl(cod)]2
with dppm and 2 in 92% yield (Scheme 1). The spectral
features of 4 were analogous to those of 3 described
above; i.e., the 31P{1H} NMR spectrum showed that the
two phosphorus atoms were placed under different
circumstances at δ -70.4 (d, J PP ) 48.2 Hz) and -59.7
(d, J PP ) 48.2 Hz) ppm. Fortunately, recrystallization
of 4 afforded yellow prismatic crystals from dichlo-
romethane/methanol suitable for single-crystal X-ray
diffraction. The structure of the diallyl ether complex 4
has been unambiguously determined by X-ray crystal-
lographic analysis. Figure 1 gives an ORTEP drawing
of the molecular structure for 4. The selected bond
distances and angles are listed in Table 1, and a
summary of the crystallographic data and structure
refinement details of 4 is given in Table 3. The molec-
ular structure of 4 shows that diallyl ether (2) coordi-
nates to the iridium metal in an η4 fashion (Figure 1).
As expected from the NMR spectral data, the geometry
of 4 is quite consistent with a distorted trigonal bipyra-
mid, in which the P2 and Cl1 atoms lie in the axial
positions and the P1 atom, C1-C2, and C5-C6 bonds
lie in the equatorial positions.22 The distances for both
C1-C2 (1.427(9) Å) and C5-C6 (1.428(9) Å) are slightly
longer than that of the olefinic C-C in the rhodium(I)
F igu r e 1. ORTEP drawing of the structure of IrCl(dppm)-
(η4-CH2dCHCH2OCH2CHdCH2) (4). Thermal ellipsoids
are shown at the 50% probability level. All hydrogen atoms
are omitted for clarity.
Ta ble 1. Selected Bon d Dista n ces a n d An gles for 4
Bond Distances (Å)
Ir(1)-C(1)
Ir(1)-C(2)
Ir(1)-C(5)
Ir(1)-C(6)
Ir(1)-P(1)
Ir(1)-P(2)
Ir(1)-Cl(1)
2.191(6)
2.182(6)
2.153(6)
2.162(6)
2.317(6)
2.233(13)
2.478(14)
C(1)-C(2)
C(2)-C(3)
C(4)-C(5)
C(5)-C(6)
O(1)-C(3)
O(1)-C(4)
1.427(9)
1.493(8)
1.501(9)
1.428(9)
1.447(9)
1.450(8)
Bond Angles (deg)
P(1)-Ir(1)-P(2)
P(1)-Ir(1)-Cl(1)
P(2)-Ir(1)-Cl(1)
P(1)-Ir(1)-C(1)
P(1)-Ir(1)-C(2)
P(1)-Ir(1)-C(5)
P(1)-Ir(1)-C(6)
P(2)-Ir(1)-C(1)
P(2)-Ir(1)-C(2)
P(2)-Ir(1)-C(5)
72.7(5)
94.1(5)
P(2)-Ir(1)-C(6)
Cl(1)-Ir(1)-C(1)
Cl(1)-Ir(1)-C(2)
Cl(1)-Ir(1)-C(5)
Cl(1)-Ir(1)-C(6)
Ir(1)-P(1)-C(7)
Ir(1)-P(2)-C(7)
P(1)-C(7)-P(2)
C(1)-C(2)-C(3)
C(4)-C(5)-C(6)
97.0(18)
86.5(16)
93.0(16)
92.8(18)
85.3(19)
93.5(17)
96.7(17)
93.8(2)
166.6(5)
91.1(17)
128.0(17)
147.4(17)
110.4(17)
95.8(15)
97.0(16)
97.2(18)
122.8(6)
122.8(6)
analogue Rh(acac)[η4-CH3CHdCHCH2OCH(CH3)CHd
CH2] (1.368 and 1.400 Å) (Table 1).6 The Ir1-Cl1 bond
is almost perpendicular to the basal plane consisting of
the P1 atom and C1-C2 and C5-C6 bonds, and not the
Ir1-P2 bond. The bite angle ân of coordinated dppm,
i.e., P1-Ir1-P2, is 72.7(5)°, which is consistent with the
natural values reported by van Leeuwen and co-workers
(ân ) 72°).23
1,2-Bis(diphenylphosphino)ethane (dppe) was also
available as the ancillary ligand to furnish the corre-
sponding η4-1,6-diene complexes 5 and 6 from 1 and 2
in 89% and 94% yields under identical conditions,
1
respectively (Scheme 2). The simplicity of the H and
13C{1H} NMR spectra of 5 and 6 suggested that these
have symmetrical structures. The 31P{1H} NMR spectra
(22) Quite recently, Oro, Astruc et al. have confirmed by an X-ray
crystallographic analysis that an analogous Fe-Ir heterodinuclear
triene complex had a similar trigonal-bipyramidal structure; see:
Marce´n, S.; J ime´nez, M. V.; Dobrinovich, I. T.; Lahoz, F. J .; Oro, L.
A.; Ruiz, J .; Astruc, D. Organometallics 2002, 21, 326-330.
(23) (a) van Leeuwen, P. W. N. M.; Kamer, P. C. J .; Reek, J . N. H.;
Dierkes, P. J . Chem. Soc., Dalton Trans. 1999, 1519-1529. (b) van
Leeuwen, P. W. N. M.; Kamer, P. C. J .; Reek, J . N. H.; Dierkes, P.
Chem. Rev. 2000, 100, 2741-2769.

Ir(I) Complexes with Diene and Diphosphine Ligands
Organometallics, Vol. 23, No. 8, 2004 1733
Ta ble 2. Selected Bon d Dista n ces a n d An gles for 8
Sch em e 2
Bond Distances (Å)
Ir(1)-C(29)
Ir(1)-C(30)
Ir(1)-C(33)
Ir(1)-C(34)
Ir(1)-P(1)
2.144(3)
2.152(3)
2.189(3)
2.221(3)
2.335(7)
2.337(7)
2.581(7)
1.428(5)
C(30)-C(31)
C(31)-C(32)
C(32)-C(33)
C(33)-C(34)
C(34)-C(35)
C(35)-C(36)
C(36)-C(29)
1.528(4)
1.521(4)
1.512(4)
1.391(5)
1.532(4)
1.530(5)
1.510(4)
Ir(1)-P(2)
Ir(1)-Cl(1)
C(29)-C(30)
Bond Angles (deg)
P(1)-Ir(1)-P(2)
93.1(5)
P(2)-Ir(1)-Cl(1)
86.1(2)
C(29)-Ir(1)-C(34) 78.9(12) Cl(1)-Ir(1)-C(29) 133.5(9)
C(30)-Ir(1)-C(33)
P(1)-Ir(1)-C(33)
P(1)-Ir(1)-C(34)
P(2)-Ir(1)-C(29)
P(2)-Ir(1)-C(30)
P(1)-Ir(1)-Cl(1)
79.7(11) Cl(1)-Ir(1)-C(30)
96.3(9)
84.3(9)
119.3(9)
117.7(10)
117.7(10)
Sch em e 3
95.8(8)
84.4(8)
85.3(9)
92.7(8)
91.0(3)
Cl(1)-Ir(1)-C(33)
Cl(1)-Ir(1)-C(6)
Ir(1)-P(1)-C(‘)
Ir(1)-P(2)-C(4)
Ta ble 3. Selected Cr ysta llogr a p h ic Da ta a n d
Str u ctu r e Refin em en t Deta ils for 4 a n d 8‚CHCl3
4
8‚CHCl3
empirical formula
fw
C
31H32ClIrOP2
C
37H41Cl4IrP2
710.16
881.64
cryst color
cryst habit
temp (K)
wavelength (Å)
cryst syst
space group
a (Å)
yellow
prismatic
173(2)
yellow
prismatic
173(2)
the expected ligand displacement did not occur even in
refluxing dichloromethane or 1,2-dichloroethane.
0.71073
monoclinic
P21/n
14.6479(13)
11.6123(11)
18.0017(16)
101.389(2)
3001.75(5)
4
1.571
4.665
1400
0.3 × 0.3 × 0.8
1.64-29.30
1.016
0.0447
0.1363
0.71073
monoclinic
P21/n
11.2689(10)
20.7628(18)
14.9551(13)
91.205(2)
3498.3(5)
4
1.674
4.240
1752
0.6 × 0.6 × 0.8
1.68-29.14
0.972
0.0278
0.0709
In a similar manner, the employment of 1,4-bis(di-
phenylphosphino)butane (dppb, n ) 4) never displaced
the cod ligand with 1 to form the cod complex IrCl(cod)-
(dppb) (8) in 98% yield (Scheme 3). The 31P{1H} spec-
trum of 8 exhibited a peak at δ 0.0 (s) ppm, which is
assigned to a pair of equivalent phosphorus atoms, the
same as for the dppp complex 7. Recrystallization of 8
from chloroform/n-hexane afforded yellow prismatic
single crystals suitable for X-ray analysis, and its
structure was unequivocally determined. Figure 2 shows
an ORTEP drawing of the molecular structure of 8. The
selected bond distances and angles and a summary of
the crystallographic data and structure refinement
details are given in Tables 2 and 3, respectively. As
depicted in Figure 2, the geometry of 8 takes a distorted-
square-pyramidal structure, in which cod and dppb exist
in the same plane and the Cl1 atom occupies the apical
position, which accounts for the characteristic difference
between 8 and 4 in the NMR spectra. The bite angle ân
of dppb in 8 (ân ) 93.1(3)° for P1-Ir1-P2) is somewhat
smaller than the natural values in the literature (ân )
98°).23 A similar observation was reported in the case
of the dppp complex 7 (ân ) 86.4(4)° for 7 versus 91° for
the natural values).23,24
b (Å)
c (Å)
â (deg)
V (Å3)
Z
Dcalcd (Mg m-3
)
abs coeff (mm-1
)
F(000)
cryst size (mm3)
scan range θ (deg)
GOF on F2
R1 (I > 2σ(I))
wR2 (I > 2σ(I))
showed pairs of signals at δ 20.8 (d, J PP ) 3.3 Hz) and
24.3 (d, J PP ) 3.3 Hz) ppm for 5 and δ 22.3 (d, J PP ) 3.4
Hz) and 25.6 (d, J PP ) 3.4 Hz) ppm for 6. These
observations apparently indicate that the dppe com-
plexes 5 and 6 also have trigonal-bipyramidal geom-
etries similar to those of the dppm complexes 3 and 4.
Subsequently, the reaction of [IrCl(cod)]2 with 1,3-bis-
(diphenylphosphino)propane (dppp, n ) 3) and the 1,6-
diene 1 (3 equiv) was examined in order to prepare
another η4-1,6-diene complex bearing a bidentate diphos-
phine ligand with a carbon linkage longer than that of
dppe. This reaction, however, did not provide the
expected η4-1,6-diene complex at all but the known
mononuclear cod complex IrCl(cod)(dppp) (7) in 98%
yield (Scheme 3).24 The obtained cod complex 7 totally
agreed with the authentic sample prepared according
to a literature procedure.24 The 31P{1H} spectrum 7
showed a feature different from that of the η4-1,6-diene
complexes 3-6; only one signal appeared at δ -13.87
(s) ppm. Notably, the cod complex 7 was so stable that
To uncover whether the η4
-1,6-diene complexes 4-7
are indeed generated via the mononuclear complexes
IrCl(cod)(diphosphine), the reaction of IrCl(cod)(dppe)
(9) with the 1,6-diene 1 was examined as depicted in
Scheme 4. Complex 9 was readily prepared from [IrCl-
(cod)]2 and dppe in 90% yield. In its 31P{1H} NMR
spectrum, only a signal at δ 35.3 (s) ppm was observed
to indicate that 9 had a square-pyramidal structure
similar to 7 and 8. To a chloroform-d solution of 9 was
added 3 equiv of 1, and the resulting yellow solution
1
was periodically monitored by H and 31P{1H} NMR at
(24) Recently, Shibata and co-workers reported the preparation of
7 by the reaction of [IrCl(cod)]2 with dppp in hot toluene. They also
determined the molecular structure of 7‚CHCl3 as square pyramidal
by single-crystal X-ray diffraction; see: Shibata, T.; Yamashita, K.;
Ishida, H.; Takagi, K. Org. Lett. 2001, 3, 1217-1219.
ambient temperature. After 1 h, a pair of new peaks
appeared at 21.0 (d, J PP ) 3.3 Hz) and 24.5 (d, J PP
)
3.3 Hz) ppm. They are assigned as two nonequivalent

1734 Organometallics, Vol. 23, No. 8, 2004
Makino et al.
F igu r e 2. ORTEP drawing of the structure of IrCl(cod)(dppb) (8). Thermal ellipsoids are shown at the 50% probability
level. All hydrogen atoms are omitted for clarity.
Sch em e 4
a trigonal-bipyramidal geometry, in which a smaller
steric repulsion is present between the η4-1,6-diene
ligand and phenyl groups bound to phosphorus atoms,
as well as a chlorine atom, than in the square-pyramidal
geometry. Therefore, the structural alteration occurred
at the dissociation step of the cod ligand upon the
transformation from a cod complex into an η4-1,6-diene
complex.
It is noteworthy that the reaction of [IrCl(cod)]2 with
1 without phosphine ligands provided pale yellow solids.
1
Although its H NMR spectrum was quite complicated
in benzene-d6, the characteristic signals corresponding
to the methoxy groups were observed at δ 3.23 (s) and
3.42 (s) ppm concomitant with that of the uncoordinated
1 at δ 3.29 (s) ppm. It was disappointing that this solid
was unstable in solution and decomposed into 1 and
unidentified iridium species. Consequently, further
characterization hardly provided any more detailed
information on the molecular structure. It is known that
the reaction of [IrCl(cod)]2 with 2 afforded the dinuclear
complex [IrCl(cod)(η4-CH2dCHCH2OCH2CHdCH2)]2,
even though the structure was ambiguous.25 We antici-
pate that the analogous dinuclear complex [IrCl(cod)-
(η4-CH2dCHCH2C(CO2Me)2CH2CHdCH2)]2 was gener-
ated in the reaction of [IrCl(cod)]2 with 1.
Since the η4-1,6-diene complexes 3-6 could be re-
garded as model intermediates of the transition-metal-
catalyzed cycloisomerization reactions of 1,6-dienes
as described above,21 we inspected the behavior of
IrCl(dppe)[η4-CH2dCHCH2C(CO2Me)2CH2CHdCH2] (5).
Though a chloroform-d solution of 5 was heated at 60
°C and monitored by 1H NMR, no cycloisomerized
product was observed, resulting in the partial decom-
position of 5 into undefined iridium complexes and 1
even after 24 h (5/1 ) 64/36 after 24 h). The addition of
a silver salt such as AgPF6, which brought about an
unoccupied coordinating site by abstraction of a chlorine
atom, had no effect. In addition, the reaction in the
presence of a trialkylsilane such as dimethylethylsilane
did not promote the cycloisomerization,13c,20c-f cycliza-
tion/hydrosilylation,13c,26,27 or even hydrosilylation reac-
tion with or without AgPF6.28
phosphorus atoms in the η4-1,6-diene complex 5, whereas
the singlet at δ 35.3 ppm in 9 still remained in the
31P{1H} NMR spectrum. Ultimately, the complete con-
version of 9 into 5 was accomplished within 12 h and
no signals for other species were observed, except for
the liberated cod. It was once again verified that the
η4-1,6-diene complexes 3-6 were generated through the
replacement of the cod ligand in IrCl(cod)(diphosphine)
with the corresponding 1,6-diene 1 or 2.
The results shown in Schemes 1-4 suggest that the
value of the bite angle ân for each diphosphine (the
natural values reported in the literatures are the
following: 72° for dppm, 85° for dppe, 91° for dppp, and
98° for dppb)23 played a key role in the liberation of the
coordinated cod ligand. We assumed that the narrow
bite angle ân in dppm and dppe provided distortion
toward the square-bipyramidal structure of the corre-
sponding cod complexes IrCl(cod)(diphosphine) to de-
crease the orbital overlap between the iridium(I) metal
and the cod ligand. As a consequence, the cod ligand
was readily dissociated, and then a more flexible acyclic
1,6-diene ligand occupied the resultant vacant sites to
afford the more stable η4-1,6-diene complexes 3-6. On
the other hand, the cod complexes 7 and 8 with the
wider bite angle ân were too stable to release the
coordinated cod ligand because those received only
negligible distortion. This strongly supports the sug-
gestion that a monodentate ligand such as PPh3 cannot
trigger such ligand replacement. The structural differ-
ence between the η4-1,6-diene complexes 3-6 and cod
complexes 7-9 might be attributed to the following: the
greater flexibility of the acyclic 1,6-diene ligands relative
to a cod ligand permitted these structures to change into
(25) Pannetier, G.; Bonnaire, R.; Fougeroux, P. J . Organomet. Chem.
1971, 30, 411-419.

Ir(I) Complexes with Diene and Diphosphine Ligands
Organometallics, Vol. 23, No. 8, 2004 1735
decoupling and are reported in terms of chemical shifts (δ,
ppm) relative to the solvent peak (77.0 ppm, the center line of
a triplet for chloroform-d). 31P{1H} NMR spectra were fully
decoupled by broad-band decoupling and are reported in terms
of chemical shifts (δ, ppm) relative to H3PO4 (85% in H2O) as
external standard. IR data were recorded on a J ASCO IR-810
Ch a r t 1
spectrometer. Absorbance frequencies are reported in cm-1
.
Fast atom bombardment mass spectra (FABMS) were mea-
sured on a J EOL J MS-AX505HA spectrometer employing
m-nitrobenzyl alcohol (NBA) as a matrix. Melting points were
measured in sealed capillary tubes and are uncorrected.
Elemental analyses were performed by the Microanalytical
Center of Kyoto University.
Unsuitable substrates for the reported ligand ex-
change reactions are depicted in Chart 1. N,N-Diallyl-
tosylamide (10) gave an intractable reaction mixture,
as was also true for the phenyl-substituted 1,6-dienes
11 and 12 and the 1,7-diene 13. Similarly, the enynes
14-17 produced unidentified viscous oils. We also
examined auxiliary ligands other than the diphosphines
as potential substrates, such as N,N,N′,N′-tetrameth-
ylethylenediamine (tmeda) and 2,2′-bipyridine (bipy),
albeit without success.
Ma ter ia ls. Chloroform, dichloromethane, n-hexane, and
n-pentane were distilled from CaH2. Methanol was distilled
from magnesium alkoxide. All solvents utilized in the reactions
29
30
were degassed prior to use. [IrCl(cod)]2 and [IrCl(coe)2]2
were prepared according to literature procedures. Dimethyl
2,2-diallylmalonate (1) was prepared from dimethyl malonate
and allyl bromide with sodium methoxide in methanol. Other
reagents were obtained from commercial sources and used
without further purification.
P r e p a r a t ion
of
Ir Cl(d p p m )[η4-CH 2dCH CH 2C-
(CO2Me)2CH2CHdCH2] (3). To a dichloromethane solution
(4 mL) of [IrCl(cod)]2 (33.7 mg, 0.050 mmol) was added dppm
(39.3 mg, 0.10 mmol). Subsequently, a solution of dimethyl
2,2-diallylmalonate (1; 64.5 mg, 0.30 mmol) in dichloromethane
(1 mL) was added to the mixture, and the resultant yellow
solution was stirred at room temperature. After 3 h, the
volatile materials were removed in vacuo. Then, the residue
was recrystallized from dichloromethane/n-hexane to afford 3
(76.1 mg, 92%) as pale yellow-green crystals (needle). Mp:
191-193 °C dec. IR (KBr): ν 1096 (s), 1150 (s), 1254 (vs), 1312
(m), 1436 (s), 1739 (vs), 2955 (m), 3046 (m) cm-1. 1H NMR (500
MHz, CDCl3): δ 2.07 (dd, J HH ) 11.5, 14.5 Hz, 2H), 2.24 (dd,
J HH ) 7.5 Hz, J PH ) 7.5 Hz, 2H), 2.43-2.49 (m, 4H), 3.52-
3.61 (m, 2H), 3.65 (s, 3H), 3.89 (s, 3H), 4.65 (dd, J PH ) 9.0,
11.0 Hz), 6.97-7.01 (m, 4H), 7.24-7.28 (m, 4H), 7.33-7.36 (m,
2H), 7.43-7.50 (m, 6H), 8.08-8.12 (m, 4H) ppm. 13C{1H} NMR
(75 MHz, CDCl3): δ 30.9 (d, J CP ) 3.8 Hz), 40.0 (d, J CP ) 6.5
Hz), 44.2 (d, J PC ) 15.2 Hz), 47.2 (dd, J PC ) 24.9, 36.8 Hz),
52.2 (s), 52.2 (s), 62.7 (d, J PC ) 9.8 Hz), 126.0 (dd, J PC ) 4.6,
48.5 Hz), 128.4 (d, J PC ) 10.6 Hz), 128.6 (d, J PC ) 10.7 Hz),
130.3 (d, J PC ) 2.3 Hz), 130.6 (d, J PC ) 2.6 Hz), 130.8 (d, J PC
) 9.5 Hz), 132.5 (d, J PC ) 12.2 Hz), 136.6 (dd, J PC ) 4.1, 32.3
Hz), 173.1 (s), 173.2 (s) ppm. 31P{1H} NMR (121 MHz,
CDCl3): δ -69.9 (d, J PP ) 45.7 Hz), -56.8 (d, J PP ) 45.7 Hz)
ppm. MS (FAB; m/z (relative intensity, %)): 419 ([Cl(dppe)]+,
19), 612 ([IrCl(dppm)]+, 100), 1224 ([Ir2Cl2(dppm)2]+, 3). Anal.
Calcd for C36H38ClIrO4P2: C, 52.45; H, 4.65. Found: C, 52.33;
H, 4.75.
Con clu sion
We have found that the reaction of [IrCl(cod)]2 with
bidentate diphosphines in the presence of 1,6-dienes
furnished the novel iridium(I) complexes IrCl(η4-1,6-
diene)(diphosphine) in excellent yields. The X-ray crys-
tallographic analysis unambiguously revealed that the
η4-1,6-diene complexes assume a distorted-trigonal-
bipyramidal geometry. On the other hand, the homolo-
gation of the carbon linkage in diphosphines resulted
in the exclusive formation of IrCl(cod)(diphosphine) with
a distorted-square-pyramidal structure, even in the
presence of 1,6-dienes.
Exp er im en ta l Section
Gen er a l Rem a r k s. Air- and moisture-sensitive reactions
were carried out under an atmosphere of argon or nitrogen
by employing standard Schlenk techniques. NMR spectra were
measured on a Varian INOVA 500 (1H at 500 MHz, 13C{1H}
at 125 MHz) or a Varian MERCURY 300 (1H at 300 MHz,
13C{1H} at 75 MHz, 31P{1H} at 121 MHz) magnetic resonance
spectrometer. 1H NMR spectra are reported in terms of
chemical shifts (δ, ppm) relative to the residual solvent peak
(7.26 ppm for chloroform-d). The multiplicities were desig-
nated as follows: s, singlet; d, doublet; t, triplet; m, multiplet.
13C{1H} NMR spectra were fully decoupled by broad-band
P r ep a r a tion of Ir Cl(d p p m )(η4-CH2dCHCH2OCH2CHd
CH2) (4). To a dichloromethane solution (20 mL) of [IrCl(cod)]2
(171.3 mg, 0.26 mmol) was added dppm (196.0 mg, 0.51 mmol).
Subsequently, a solution of diallyl ether (2; 152.5 mg, 1.55
mmol) in dichloromethane (5 mL) was added to the mixture,
and the resultant yellow solution was stirred at room tem-
perature. After 3 h, the volatile materials were removed in
vacuo. Then, the residue was recrystallized from dichlo-
romethane/n-pentane to afford 4 (331.9 mg, 92%) as yellow
crystals (prismatic). Mp: 151-153 °C dec. IR (KBr): ν 925
(m), 1053 (m), 1098 (vs), 1184 (m), 1332 (m), 1435 (s), 1479
(m), 2850 (m), 2907 (s), 2965 (m), 3050 (m) cm-1. 1H NMR (500
MHz, CDCl3): δ 2.27 (dd, J HH ) 7.5 Hz, J PH ) 7.5 Hz, 2H),
2.42 (d, J HH ) 11.0 Hz, 2H), 3.34 (dd, J HH ) 11.8, 11.8 Hz,
(26) Y: (a) Molander, G. A.; Nichols, P. J . J . Am. Chem. Soc. 1995,
117, 4415-4416. (b) Molander, G. A.; Nichols, P. J .; Noll, B. C. J . Org.
Chem. 1998, 63, 2292-2306. Nd: (c) Onozawa, S.; Sakakura, T.;
Tanaka, M. Tetrahedron Lett. 1994, 35, 8177-8180. Pd: (d) Widen-
hoefer, R. A.; DeCarli, M. A. J . Am. Chem. Soc. 1998, 120, 3805-3806.
(e) Widenhoefer, R. A.; Vadehra, A. Tetrahedron Lett. 1999, 40, 8499-
8502. (f) Widenhoefer, R. A.; Stengone, C. N. J . Org. Chem. 1999, 64,
8681-8692. (g) Pei, T.; Widenhoefer, R. A. Org. Lett. 2000, 2, 1469-
1471. (h) Perch, N. S.; Pei, T.; Widenhoefer, R. A. J . Org. Chem. 2000,
65, 3836-3845. (i) Wang, X.; Chakrapani, H.; Stengone, C. N.;
Widenhoefer, R. A. J . Org. Chem. 2001, 66, 1755-1760. For application
of the yttrium-catalyzed cyclization/hydrosilylation of 1,n-dienes to the
total synthesis of (()-epilupinine, see: (j) Molander, G. A.; Nichols, P.
J . J . Org. Chem. 1996, 61, 6040-6043.
(27) Recently, Widenhoefer and co-workers have prepared a cationic
palladium(II) cyclopentyl chelate complex from the reaction of the
cationic palladium(II) phenanthroline complex with 1 and determined
the molecular structure by X-ray crystallographic analysis.20f
(28) Widenhoefer et al. have also reported that the cationic palla-
dium(II) phenanthroline complex rapidly reacted with 1 in the presence
of triethylsilane to form a palladium(II) 5-hexenyl chelate complex.
This unprecedented complex facilely converted the palladium(II)
cyclopentyl chelate via â-migratory insertion; see: Perch, N. S.;
Widenhoefer, R. A. Organometallics 2001, 20, 5251-5253.
2H), 3.58-3.66 (m, 2H), 3.95 (ddd, J HH ) 4.0, 11.8 Hz, J PH
)
(29) Crabtree, R. H.; Morris, G. E. J . Organomet. Chem. 1977, 135,
395-403.
(30) Herde, J . L.; Lambert, J . C.; Senoff, C. V. Inorg. Chem. 1974,
15, 18-20.

1736 Organometallics, Vol. 23, No. 8, 2004
Makino et al.
8.0 Hz, 2H), 4.70 (dd, J PH ) 9.0, 11.0 Hz, 2H), 7.03-7.07 (m,
4H), 7.27-7.31 (m, 4H), 7.35-7.39 (m, 2H), 7.45-7.51 (m, 6H),
8.07-8.12 (m, 4H) ppm. 13C{1H} NMR (75 MHz, CDCl3): δ
mg, 0.34 mmol) in dichloromethane (2 mL) was added to the
mixture, and the resultant light brown solution was stirred
at room temperature. After 3 h, the volatile materials were
removed in vacuo. Then, the residue was recrystallized from
dichloromethane/n-hexane to afford 7 (81.0 mg, 98%) as yellow
crystals (prismatic). Mp: 181-183 °C dec. IR (KBr): ν 833
(w), 916 (w), 973 (s), 1094 (vs), 1150 (m), 1191 (w), 1268 (m),
1328 (m), 1433 (vs), 1483 (s), 1586 (w), 2824 (s), 2867 (s), 2917
(s), 3052 (s) cm-1. 1H NMR (300 MHz, CDCl3): δ 1.91 (bd, J PH
) 8.7 Hz, 6H), 2.43 (bs, 6H), 3.23 (bs, 6H), 7.28 (bs, 12H), 7.57
(bs, 8H) ppm. 31P{1H} NMR (121 MHz, CDCl3): δ -13.9 (s)
ppm. MS (FAB; m/z (relative intensity, %)): 640 ([IrCl(dppp)]+,
77), 713 ([Ir(cod)(dppp)]+, 100). Anal. Calcd for C35H38ClIrP2:
C, 56.18; H, 5.12. Found: C, 56.02; H, 5.30.
36.4 (d, J PC ) 5.3 Hz), 47.5 (d, J PC ) 14.0 Hz), 48.0 (dd, J PC
)
25.8, 37.1 Hz), 64.5 (d, J PC ) 4.6 Hz), 126.4 (dd, J PC ) 4.4,
48.9 Hz), 128.5 (d, J PC ) 10.2 Hz), 128.6 (d, J PC ) 10.2 Hz),
130.4 (d, J PC ) 2.3 Hz), 130.7 (d, J PC ) 2.7 Hz), 130.9 (d, J PC
) 9.1 Hz), 132.4 (d, J PC ) 11.7 Hz), 136.4 (dd, J PC ) 3.8, 34.1
Hz) ppm. 31P{1H} NMR (121 MHz, CDCl3): d -70.4 (d, J PP
)
48.2 Hz), -59.7 (d, J PP ) 48.2 Hz) ppm. MS (FAB; m/z (relative
intensity, %)): 612 ([IrCl(dppm)]+, 100), 675 ([Ir(C6H10O)-
(dppm)]+, 7), 710 (M+, 4). Anal. Calcd for C31H32ClIrOP2: C,
52.43; H, 4.54. Found: C, 52.63; H, 4.72.
P r e p a r a t io n
o f
I r C l(d p p e )[η4-C H 2dC H C H 2C -
P r epar ation of Ir Cl(cod)(dppb) (8). To a dichloromethane
solution (3 mL) of [IrCl(cod)]2 (35.2 mg, 0.052 mmol) was added
dppb (44.0 mg, 0.10 mmol). Subsequently, a solution of 1 (68.2
mg, 0.32 mmol) in dichloromethane (2 mL) was added to the
mixture, and the resultant yellow-brown solution was stirred
at room temperature. After 3 h, the volatile materials were
removed in vacuo. Then, the residue was recrystallized from
dichloromethane/n-hexane to afford 8 (76.7 mg, 98%) as yellow
crystals (prismatic). Mp: 160-163 °C dec. IR (KBr): ν 899
(m), 1010 (w), 1094 (s), 1134 (w), 1158 (m), 1269 (w), 1326 (w),
1434 (vs), 1481 (m), 1542 (w), 1586 (w), 2823 (m), 2873 (m),
(CO2Me)2CH2CHdCH2] (5). To a dichloromethane solution
(25 mL) of [IrCl(cod)]2 (206.6 mg, 0.31 mmol) was added dppe
(244.8 mg, 0.61 mmol). Subsequently, a solution of 1 (394.9
mg, 1.86 mmol) in dichloromethane (5 mL) was added to the
mixture, and the resultant red-orange solution was stirred at
room temperature. After 3 h, the volatile materials were
removed in vacuo. Then, the residue was recrystallized from
dichloromethane/n-pentane to afford 5 (459.9 mg, 89%) as
white crystals (needle). Mp: 153-155 °C dec. IR (KBr): ν 1065
(s), 1098 (s), 1142 (s), 1191 (s), 1229 (vs), 1310 (m), 1432 (s),
1736 (vs), 2949 (m), 3047 (m) cm-1 1H NMR (500 MHz,
.
1
2926 (m), 3049 (m) cm-1. H NMR (300 MHz, CDCl3): δ 1.23
CDCl3): δ 1.97 (dd, J HH ) 11.3 Hz, J PH ) 2.8 Hz, 2H), 2.12
(dd, J HH ) 11.8, 14.3 Hz, 2H), 2.26-2.43 (m, 8H), 3.10-3.18
(m, 2H), 3.57 (s, 3H), 3.70 (s, 3H), 7.18-7.22 (m, 4H), 7.30-
7.34 (m, 4H), 7.38-7.46 (m, 8H), 7.82-7.86 (m, 4H) ppm.
13C{1H} NMR (75 MHz, CDCl3): δ 26.5 (dd, J PC ) 6.7, 40.0
Hz), 30.2 (d, J PC ) 3.1 Hz), 34.2 (dd, J PC ) 17.0, 44.3 Hz), 39.7
(d, J PC ) 6.7 Hz), 47.2 (d, J PC ) 14.0 Hz), 52.1 (s), 52.3 (s),
62.3 (d, J PC ) 8.5 Hz), 126.5 (d, J PC ) 51.5 Hz), 127.9 (d, J PC
) 9.7 Hz), 128.4 (d, J PC ) 9.7 Hz), 129.8 (d, J PC ) 2.5 Hz),
130.6 (d, J PC ) 2.4 Hz), 132.2 (d, J PC ) 7.9 Hz), 132.8 (d, J CP
) 9.7 Hz), 137.4 (d, J PC ) 43.7 Hz), 172.4 (s), 173.3 (s) ppm.
31P{1H} NMR (121 MHz, CDCl3): δ 20.8 (d, J PP ) 3.3 Hz), 24.3
(d, J PP ) 3.3 Hz) ppm. MS (FAB; m/z (relative intensity, %)):
626 ([IrCl(dppe)]+, 100), 803 ([Ir(C11H16O4)(dppe)]+, 27). Anal.
Calcd for C37H40ClIrO4P2: C, 53.01; H, 4.81. Found: C, 52.89;
H, 4.75.
(bs, 4H), 1.83 (bd, J PH ) 8.7 Hz, 4H), 2.32-2.42 (m, 4H), 3.00
(bs, 4H), 3.18 (bs, 4H), 7.31-7.34 (m, 12H), 7.61-7.68 (m, 8H)
ppm. 31P{1H} NMR (121 MHz, CDCl3): δ 0.0 (s) ppm. MS
(FAB; m/z (relative intensity, %)): 725 (Ir(cod)(dppb) - 2H+,
100). Anal. Calcd for C36H40ClIrP2: C, 56.72; H, 5.29. Found:
C, 56.51; H, 5.42.
P r epar ation of Ir Cl(cod)(dppe) (9). To a dichloromethane
solution (6 mL) of [IrCl(cod)]2 (40.7 mg, 0.061 mmol) was added
dppe (48.9 mg, 0.12 mmol), and the resultant yellow solution
was stirred at room temperature for 30 min. After the volatile
materials were removed in vacuo, the residue was recrystal-
lized from dichloromethane/n-hexane to afford 9 (80.4 mg, 90%)
as yellow crystals (prismatic). Mp: 177-180 °C dec. IR
(KBr): ν 814 (w), 886 (w), 999 (w), 1099 (vs), 1185 (m), 1244
(w), 1326 (m), 1435 (vs), 1483 (m), 1573 (m), 1998 (w), 2817
1
(m), 2868 (m), 2904 (m), 3046 (m) cm-1. H NMR (300 MHz,
P r ep a r a tion of Ir Cl(d p p e)(η4-CH2dCHCH2OCH2CHd
CH2) (6). To a dichloromethane solution (3 mL) of [IrCl(cod)]2
(34.4 mg, 0.051 mmol) was added dppe (41.7 mg, 0.11 mmol).
Subsequently, a solution of 2 (31.4 mg, 0.32 mmol) in dichlo-
romethane (2 mL) was added to the mixture, and the resultant
yellow solution was stirred at room temperature. After 3 h,
the volatile materials were removed in vacuo. Then, the
residue was recrystallized from dichloromethane/n-hexane to
afford 6 (70.0 mg, 94%) as yellow crystals (needle). Mp: 138-
140 °C dec. IR (KBr): ν 817 (m), 926 (m), 1062 (s), 1099 (vs),
1184 (s), 1252 (m), 1333 (m), 1433 (vs), 1480 (vs), 2853 (s),
CDCl3): δ 2.01 (bd, J PH ) 8.4 Hz, 4H), 2.37-2.54 (m, 8H), 3.72
(bs, 4H), 7.31-7.37 (m, 12H), 7.52-7.59 (m, 8H) ppm. 31P{1H}
NMR (121 MHz, CDCl3): δ 35.3 (s) ppm. MS (FAB; m/z
(relative intensity, %)): 697 ([Ir(cod)(dppe)]+ - 2H, 100). Anal.
Calcd for C34H36ClIrP2: C, 55.62; H, 4.94. Found: C, 55.38;
H, 5.02.
X-r a y Cr ysta llogr a p h ic Str u ctu r a l Deter m in a tion s of
4 a n d 8‚CHCl3. The single crystals of 4 and 8‚CHCl3 suitable
for X-ray diffraction analysis were obtained by recrystallization
from dichloromethane/methanol for 4 or from chloroform/n-
hexane for 8‚CHCl3. A crystal of dimensions 0.3 × 0.3 × 0.8
mm (4) or 0.6 × 0.6 × 0.8 mm (8‚CHCl3) was mounted on a
quartz fiber, and diffraction data were collected in the θ range
of 1.64-29.30° for 4 and 1.68-29.14° for 8‚CHCl3, respectively,
at 173 K on a Brucker SMART APEX CCD diffractometer with
graphite-monochromated Mo KR radiation (λ ) 0.710 73 Å).
The absorption correction was made using SADABS. The
structure was solved by direct methods and refined by full-
matrix least squares on F2 by using SHELXTL. All non-
hydrogen atoms were refined with anisotropic displacement
parameters. All hydrogen atoms were placed in calculated
positions. Final refinement details are compiled in Tables S1-1
and S2-1 (Supporting Information).
2907 (vs), 2978 (s), 3055 (vs) cm-1 1H NMR (500 MHz,
.
CDCl3): δ 1.92 (dd, J HH ) 11.3 Hz, J PH ) 2.3 Hz, 2H), 2.20
(dd, J HH ) 6.8 Hz, J PH ) 6.8 Hz, 2H), 2.30-2.46 (m, 4H), 3.13-
3.21 (m, 2H), 3.41 (dd, J HH ) 11.5, 12.0 Hz, 2H), 3.86 (ddd,
J HH ) 3.5, 11.5 Hz, J HP ) 7.0 Hz, 2H), 7.25-7.29 (m, 4H),
7.33-7.36 (m, 4H), 7.41-7.47 (m, 8H), 7.83-7.87 (m, 4H) ppm.
13C{1H} NMR (75 MHz, CDCl3): δ 26.9 (dd, J PC ) 6.5, 31.1
Hz), 34.3 (dd, J PC ) 17.1, 43.6 Hz), 36.1 (d, J PC ) 6.1 Hz), 49.9
(d, J PC ) 13.7 Hz), 63.9 (d, J PC ) 3.8 Hz), 126.4 (d, J PC ) 51.5
Hz), 127.9 (d, J PC ) 9.9 Hz), 128.5 (d, J PC ) 9.9 Hz), 129.7 (d,
J PC ) 2.0 Hz), 130.8 (d, J PC ) 2.6 Hz), 132.2 (d, J PC ) 8.3 Hz),
132.8 (d, J PC ) 9.8 Hz), 137.3 (d, J PC ) 44.8 Hz) ppm. 31P{1H}
NMR (121 MHz, CDCl3): δ 22.3 (d, J PP ) 3.4 Hz), 25.5 (d, J PP
) 3.4 Hz) ppm. MS (FAB; m/z (relative intensity, %)): 626
([IrCl(dppe)]+, 100). Anal. Calcd for C32H34ClIrOP2: C, 53.07;
H, 4.73. Found: C, 52.89; H, 4.88.
Ack n ow led gm en t. This work was supported by a
Grant-in-Aid for Scientific Research and the 21st Cen-
tury COE Program “Nature-Guided Materials Process-
ing” of the Ministry of Education, Culture, Sports,
Science, and Technology of J apan. We also gratefully
P r epar ation of Ir Cl(cod)(dppp) (7). To a dichloromethane
solution (3 mL) of [IrCl(cod)]2 (37.4 mg, 0.056 mmol) was added
dppp (45.4 mg, 0.11 mmol). Subsequently, a solution of 1 (72.6

Ir(I) Complexes with Diene and Diphosphine Ligands
Organometallics, Vol. 23, No. 8, 2004 1737
drawings of the full structures of 4 and 8‚CHCl3; alternatively,
these data can be acquired as a CIF file. This material is
available free of charge via the Internet at http://pubs.acs.org.
The supplementary crystallographic data for 4 and 8‚CHCl3
are also available free of charge from the Cambridge Crystal-
lographic Data Centre via the Internet at http://www.ccdc.
cam.ac.uk. The CCDC file numbers of 4 and 8‚CHCl3 are as
follows: 4, CCDC 223428; 8‚CHCl3, CCDC 223429.
acknowledge Dr. Kozo Matsumoto, Mr. Haruhisa Chou-
shi, and Mr. Shin-ichi Komai for the mass spectral
measurements.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal-
lographic data and structure refinement details, atomic coor-
dinates and equivalent isotropic displacement parameters,
bond lengths and bond angles, anisotropic displacement
parameters, and hydrogen coordinates and isotropic displace-
ment parameters for 4 and 8‚CHCl3 and figures giving ORTEP
OM034282Y