Synthesis of rhodium-carbonyl complexes bearing a novel P,N-chelating ligand of Schiff-base type

Article abstract of DOI:10.1016/j.poly.2009.06.043

Schiff-base type N,P-chelating ligands, phosphorus analogues of imino-anilido ligands, were designed and synthesized as a new type of ligands toward transition metals, and the rhodium-carbonyl complexes bearing the novel imino-phosphido and phosphaalkenyl

Full text of DOI:10.1016/j.poly.2009.06.043

Polyhedron 29 (2010) 425–433
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Synthesis of rhodium–carbonyl complexes bearing a novel P,N-chelating ligand
of Schiff-base type
*
Takahiro Sasamori , Teruyuki Matsumoto, Norihiro Tokitoh
Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Available online 24 June 2009
Schiff-base type N,P-chelating ligands, phosphorus analogues of imino–anilido ligands, were designed
and synthesized as a new type of ligands toward transition metals, and the rhodium–carbonyl complexes
bearing the novel imino–phosphido and phosphaalkenyl-anilido ligands were synthesized as stable crys-
talline compounds. Their structures were definitively revealed by X-ray crystallographic analysis, show-
ing the unique electronic features of the ligands. In addition, the effective trans-influence of the
phosphorus atom was suggested on the basis of the structural parameters and spectroscopic features
of the isolated complexes.
Keywords:
Schiff-base
Phosphorus
Phosphaalkene
Rhodium
Steric protection
trans-Influence
Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction
pounds should be one of the exciting research targets as new
promising ligands toward transition metals in catalytic chemistry
Schiff-base type N,N0-chelating ligands such as b-diketiminato
and imino–anilido ligands (Scheme 1) have been utilized for the
stabilization of unique species of transition metals and main group
elements [1]. Thus, the coordination chemistry of the Schiff-base li-
gands has attracted much interest in the research field of not only
fundamental chemistry but also industrial chemistry from the
viewpoints of supporting ligands of the catalysts for olefin poly-
merization [2]. The features of the b-diketiminato and imino–ani-
lido ligands can be mentioned as follows: (i) facile preparation,
(ii) strong coordination ability to the central atom in a monovalent
and bidentate fashion, (iii) steric effect afforded by the substituents
[3], since the low-coordinated phosphorus species exhibit low-ly-
*
ing
p -orbital level showing strong p-electron accepting character
with effective trans-effect.
Recently, we have designed a novel b-ketophosphenato ligand,
which is a heavier congener of b-ketiminato ligand, as a monova-
lent and bidentate ligand bearing an extremely bulky steric protec-
tion group, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (denoted as
Tbt) group, on the phosphorus atom (Scheme 2) [7]. It was demon-
strated that the rhodium complex 2 coordinated with the b-keto-
phosphenato ligand was synthesized as
a stable crystalline
compound, showing strong trans-influence and trans-effect of the
sp2-hybridized phosphorus atom. Now, much attention has been
focused on the heavier element analogue of b-diketiminato and
imino–anilido ligands due to their expected features reflecting
the unique characters of both b-diketiminate-type skeleton and
low-coordinated organophosphorus compounds (Scheme 1). While
the complexation of an iminophospholido ligand with copper is
known to give a unique cluster complex, the iminophospholido li-
gand did not work as a monovalent and bidentate ligand [8].
Although Mindiola et al. have postulated the existence of an inter-
mediary titanium complex 3 bearing a P,N-chelating Schiff-base li-
gand (Scheme 3) [9], there has been no example for the isolation of
a transition metal complex bearing such phosphorus analogue of a
b-diketiminato ligand [10]. On the other hand, Ionkin et al. have re-
ported the attempted synthesis of a phosphorus analogue of b-dik-
on the nitrogen atoms, (iv) electronic effect due to the p-electron
conjugation in the cyclic skeleton of the resulting complexes.
On the other hand, the coordination chemistry of low-coordi-
nated organophosphorus compounds has drawn a great deal of re-
cent attention due to their unique electronic features, i.e., the
*
characteristic low-lying
p -orbital level [3]. Generally, low-coordi-
nated organophosphorus compounds are highly reactive toward
oxygen and moisture and difficult to be handled under ambient
conditions due to their extremely high reactivity toward self-olig-
omerization. However, several numbers of low-coordinated orga-
nophosphorus compounds such as phosphaalkenes (P@C) and
diphosphenes (P@P) have been synthesized and isolated as stable
compounds by taking advantage of kinetic stabilization using
bulky substituents [4], since the isolation of stable phosphaalkenes
[5,6]. Recently, such low-coordinated organophosphorus com-
*
etiminate 6 bearing 2,4,6-tri-tert-butylphenyl (denoted as Mes )
group [11]. However, it was suggested that 6 undergoes ready
intramolecular cyclization to afford 1H-[1,2]diphosphole deriva-
tive 5 along with the elimination of Mes H (Scheme 3). Taking this
* Corresponding author. Tel.: +81 774 38 3202; fax: +81 774 38 3209.
E-mail address: sasamori@boc.kuicr.kyoto-u.ac.jp (T. Sasamori).
*
0277-5387/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2009.06.043

426
T. Sasamori et al. / Polyhedron 29 (2010) 425–433
report into consideration, the more strained b-iminophosphido
R
R
R
R
N
N
N
N
skeleton fused with a benzene ring may be helpful to avoid such
intramolecular cyclization. Thus, we have designed benzo-fused
P,N-chelating ligand 7 as a phosphorus analogue of a Schiff-base li-
gand (Scheme 4). In this case, however, the reaction of 9 with KH as
a base afforded the corresponding 2-phospha-2H-isoindole 10
β-diketiminate
N,N-Chelating ligands
phosphorus analogues
imino-anilide
*
along with the elimination of Mes H (Scheme 5) [12].
In this paper, we report the synthesis of novel rhodium–car-
bonyl complexes 11 and 13, which are isomeric complexes bearing
different types of phosphorus analogues of Schiff-base ligands 7
and 8, respectively, as stable crystalline compounds (Scheme 6).
Their structures and properties were revealed on the basis of spec-
troscopic and X-ray crystallographic analyses, indicating the trans-
influence of the low-coordinated phosphorus atoms.
R
R
R
R
R
R
N
P
P
N
N
P
Mes*
Dip
Dip
Mes*
imino-phosphide phosphaalkenyl-
anilide
P
N
N
P
N,P-Chelating ligands
Scheme 1.
7
8
imino-phosphide
phosphaalkenyl-anilide
(cod)
Rh
Schiff-base type N,P-chelating ligands
O
1) LDA
Tbt
Scheme 4.
O
P
2) [RhCl(cod)]2
Tbt
P
H
THF
R
R = H, SiMe3
R
1
2
Dip
N
Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl
cod = cyclooctadiene
Mes*
Dip
P
PH
N
Scheme 2.
KH
+ Mes*H
C6D6
60 ºC
9
10
(t-Bu)
Dip
Scheme 5.
R
R
CH2
N
Ti
Mes*
Dip
N
P
OC CO
Rh
R'
Mes*: R = R' = t-Bu
Mes*
Dip
Mes*
Dip
R
3
Dip: R = i-Pr, R' = H
PH
N
[RhCl(CO)2]2
Et3N
P
N
proposed as a possible
intermediate
THF
60 ºC
9
11
P
base
Mes*
Mes*
P Mes*
P
Cl
P
Cl
OC CO
Rh
N
– HCl
– Mes*H
Dip
Mes*
Dip
Mes*
4
5
NH
P
[RhCl(CO)2]2
Et3N
P
Mes*
no
H
Mes*
P
P
C6D6
60 ºC
6
12
13
Scheme 3.
Scheme 6.

T. Sasamori et al. / Polyhedron 29 (2010) 425–433
427
2. Results and discussion
Dip
Two types of novel ligands 7 and 8 were designed as phospho-
rus analogues of Schiff-base type ligands, and we prepared 9 and
12 as their precursors. Since such secondary phosphine and phos-
phaalkene derivatives should have high liability to oxidation and
Mes*
P
N
*
self-oligomerization, bulky Mes group should be introduced on
C1
C3
the phosphorus atom for the steric protection. Compound 9 was
prepared according to the previously reported procedures [12].
Similarly, compound 12 was synthesized as shown in Scheme 7.
The structures of 9 and 12 were reasonably supported by the spec-
troscopic and X-ray crystallographic analyses Figs. 1 and 2. Both 9
and 12 exhibit high planarity of the skeleton consisting of the cen-
tral P, N, C atoms, the fused aromatic ring, and ipso-carbon atoms
C2
Fig. 1. Molecular structure of 9. Displacement ellipsoids were drawn at the 50%
level. Hydrogen atoms were omitted for clarity. Selected bond lengths (Å) and
angles (°): P–C1, 1.8440(18); P–C(Mes ), 1.8475(7); N–C3, 1.265(2), N–C(Dip),
1.428(2); C1–C2, 1.417(2); C2–C3, 1.465(2); (Mes )C–P–C1, 100.33(7); P–C1–C2,
121.37(12); C1–C2–C3, 123.37(15); C2–C3–N, 123.45(15); C3–N–C(Dip),
119.36(14).
*
*
of Mes and Dip (2,6-diisopropylphenyl) groups. While the position
*
of the hydrogen atom of the NH and PH moieties cannot be defin-
itively determined due to the inherent principle of X-ray crystallo-
graphic analysis, the N@C moiety of 9 and the P@C moiety of 12 are
oriented toward the PH and NH moieties, respectively, indicating
the existence of weak N–H–P hydrogen bonding. The P–C1 and
N@C3 bond lengths of 9 [1.8440(18) and 1.265(2) Å, respectively]
are similar to those of typical P–C and N@C bond lengths and sug-
gest little contribution of the resonance structure 9B with effective
ized phosphorus atom with the P@C double bond character. In the
1H NMR spectrum of 12, the signal due to the P@CH moiety was
observed at dH = 8.53 as a doublet signal with 2JPH = 23.7 Hz, which
is similar to that of (E)–Mes P@CHPh [the chemical shift of P@CH
moiety is dH = 8.12 with JPH = 25.3 Hz] [15]. Interestingly, the N–
H proton of 12 was observed at dH = 6.93, which is in lower field
than that of diphenylamine (ca. 5.6 ppm) [16], as a doublet signal
with the coupling constant of 20.7 Hz. The observed J coupling
*
p-conjugation shown in Scheme 8. Similarly, phosphaalkenyl-
2
amine 12 dominantly exhibit the canonical structure of 12A
(Scheme 8) on the basis of its P@C3 and N–C1 bond lengths
[1.687(2) and 1.372(3) Å, respectively], which are similar to those
*
of (E)–Mes P@CHPh [1.660(6) Å] [13] and typical diarylamines.
1
should be due to the through-space JPH coupling of the N–H–P
In the 31P NMR spectrum, compound 9 showed dP = ꢀ62.7 in the
high field region similar to those of secondary phosphines. In the
1H NMR spectrum of 9, a characteristic doublet signal due to the
P–H moiety was observed at 6.51 ppm with 1JPH = 258.3 Hz, which
is relatively low-field shifted as compared with those of diaryl-
phosphines (around 5 ppm) [14], indicating the weak P–H–N
hydrogen bonding. The signal due to the N@CH moiety was ob-
moiety, strongly indicating the N–H–P hydrogen bonding. Thus,
the structural and spectroscopic features of 9 and 12 suggested
the little contribution of their canonical structures of B type
(Scheme 8) and the N–H–P hydrogen bonding with the formation
of the N–H–P–C–C–C ring system.
Attempted deprotonation reactions of 9 and 12 using n-BuLi
and LDA were unsuccessful to give a complicated mixture, while
9 was found to be inert toward KH in C6H6 at room temperature.
However, heating of C6D6 suspension of 9 in the presence of KH
4
served at dH = 8.53 as a doublet signal with JPH = 1.6 Hz. On the
other hand, 12 showed a characteristically low-field shifted signal
of dP = 241.2 in the 31P NMR spectrum, supporting the sp2-hybrid-
*
at 60 °C afforded 2-phospha-2H-isoindole 10 along with Mes H
Dip
Br
O
NH
O
NaO(t-Bu) (1.4 eq.)
O
O
+ DipNH2
Pd(OAc)2 (2.4 mol%)
DPEphos (3.6 mol%)
toluene
14
15
75%
95-120 ºC
Dip
Mes*
Dip
NH
P
NH
O
Mes*P(SiMe3)Li
p-TsOH
toluene
r.t.
THF
–78 ºC
16
91%
12
22%
PPh2
O
PPh2
DPEphos =
Scheme 7.

428
T. Sasamori et al. / Polyhedron 29 (2010) 425–433
O1
O2
Dip
C5
C3
Mes*
Rh
C4
P
Mes*
P
N
Dip
C3
C2
N
C1
C1
C2
Fig. 2. Molecular structure of 12. Displacement ellipsoids were drawn at the 50%
level. Hydrogen atoms were omitted for clarity. Selected bond lengths (Å) and
angles (°): N–C1, 1.372(3); N–C(Dip), 1.432(3); P–C3, 1.687(2), P–C(Mes ), 1.841(2);
*
Fig. 3. Molecular structure of 11. Displacement ellipsoids were drawn at the 50%
level. Hydrogen atoms were omitted for clarity. Selected bond lengths (Å) and
angles (°): P–Rh, 2.2665(11); N–Rh, 2.080(3); Rh–C4, 1.852(4); Rh–C5, 1.943(4);
C1–C2, 1.425(3); C2–C3, 1.454(3); (Dip)C–N–C1, 124.49(17); N–C1–C2, 120.58(18);
*
C1–C2–C3, 124.47(18); C2–C3–P, 129.24(16); C3–P–C(Mes ), 102.62(9).
*
C4–O1, 1.142(4); C5–O2, 1.106(4); P–C1, 1.768(3); P–C(Mes ), 1.840(3); N–C3,
1.308(4), N–C(Dip), 1.452(4); C1–C2, 1.424(4); C2–C3, 1.432(4); P–Rh–N, 89.93(7);
*
Rh–P–C1, 116.64(10); Rh–N–C3, 132.5(2); (Mes )C–P–C1, 109.62(15); P–C1–C2,
121.6(2); C1–C2–C3, 126.2(3); C2–C3–N, 130.0(3); C3–N–C(Dip), 114.0(3).
H
H
Mes*
Dip
H
Mes*
Dip
H
P
N
N
P
P
N
N
O1
C4
O2
C5
C3
Rh
9A
9B
Mes*
P
N
H
H
Dip
Dip
Mes*
H
Dip
Mes*
H
P
C1
C2
12A
12B
Fig. 4. Molecular structure of 13. Displacement ellipsoids were drawn at the 50%
level. Hydrogen atoms were omitted for clarity. Selected bond lengths (Å) and
angles (°): P–Rh, 2.2261(12); N–Rh, 2.066(4); Rh–C4, 1.933(5); Rh–C5, 1.844(5);
C4–O1, 1.131(5); C5–O2, 1.143(6); N–C1, 1.374(6); N–C(Dip), 1.450(6); P–C3,
Scheme 8.
*
1.666(5), P–C(Mes ), 1.818(5); C1–C2, 1.435(7); C2–C3, 1.428(7); N–Rh–P,
88.29(11); Rh–N–C1, 136.6(3); Rh–P–C3, 118.91(17); (Dip)C–N–C1, 115.3(4); N–
*
C1–C2, 124.0(4); C1–C2–C3, 125.5(4); C2–C3–P, 126.6(4); C3–P–C(Mes ), 110.5(2).
as described above (Scheme 5) [12]. When 9 was treated with
0.5 eq. of [RhCl(CO)2]2 in C6H6 at room temperature, the reaction
proceeded slowly to give an unidentified complex X, which showed
11opt is 717°, Fig. 7). However, the structural optimization of the
less hindered model compound 11Me bearing a methyl group in-
stead of Mes group in 11 was found to have a highly distorted
1
a
characteristic signal at dP = ꢀ14.1 with JPRh = 164 Hz and
1JPH = 378 Hz in the 31P NMR spectrum. Treatment of the reaction
mixture with an excess amount of Et3N at 60 °C for 6 h afforded
the rhodium–carbonyl complex 11 as a stable deep purple crystal-
line compound (Scheme 6). Similarly, heating of the C6H6 solution
of 12 with 0.5 eq. of [RhCl(CO)2]2 in the presence of an excess
amount of Et3N afforded the corresponding rhodium–carbonyl
complex 13 as a stable purplish red crystalline compound. Rho-
dium complexes 11 and 13 can be handled in the air without any
*
structure with a phosphorus atom showing a pyramidal geometry
(the sum of the internal angles of the Rh–P–C–C–C–N six-mem-
*
bered ring skeleton is 686°). That is, the Mes group of 11 should
play an important role to afford the steric effect on the phosphorus
atom for keeping the relatively planar geometry with sp2-hybrid-
ization and preventing the phosphorus atom from pyramidaliza-
tion. On the other hand, the structural parameters of the ligand
moiety of 13 are similar to those of 12, indicating the less elec-
tronic effect toward the ligand moiety by the complexation with
*
decomposition probably due to the steric effect afforded by Mes
and Dip groups (Figs. 3 and 4).
The structural parameters of rhodium–carbonyl complexes 11
and 13 were revealed by the X-ray crystallographic analysis (Figs.
3–7). In the case of 11, the P–C1 and C2–C3 bonds are shortened
and the C1–C2 and C3–N bonds are elongated as compared with
the corresponding bonds of 9, suggesting the considerably delocal-
a rhodium atom. That is, the N–C [1.374(6) Å] and P@C
[1.666(5) Å] bond lengths of 13 are similar to those of 12 [N–C:
1.372(3) Å and P@C: 1.687(2) Å] in contrast to the case of 9 and
11 as described above. As in the case of 11, the central six-mem-
bered ring skeleton of Rh–P–C–C–C–N of 13 exhibits an almost pla-
nar skeleton (the sum of the internal angles of the Rh–P–C–C–C–N
six-membered ring skeleton is 720°), while the theoretically opti-
mized structure of 13opt [17] is similar to those observed by the
X-ray crystallographic analysis of 13. However, the methyl-substi-
tuted model 13Me exhibits a slightly twisted structure as in the
case of 11Me (the sum of the internal angles of the Rh–P–C–C–C–
N six-membered ring skeleton is 712°), suggesting the steric effect
ized p-electrons of the central six-membered ring skeleton of Rh–
P–C–C–C–N. The sum of the internal angles of the Rh–P–C–C–C–N
six-membered ring skeleton of 11 is 717°, showing its high planar-
ity with the slightly pyramidalized phosphorus atom. The theoret-
ically optimized structure of 11opt [17] is similar to that of 11 with
the slightly pyramidalized phosphorus atom (the sum of the inter-
nal angles of the Rh–P–C–C–C–N six-membered ring skeleton of

T. Sasamori et al. / Polyhedron 29 (2010) 425–433
429
(a)
(a)
P
N
Rh
P
N
Rh
(b)
(c)
(b)
(c)
P
N
N
P
Rh
Rh
P
Rh
N
N
Rh
P
Fig. 6. (a) Observed structure of 13. (b) Optimized structure of 13opt [17]. (c)
Optimized structure of 13Me [17].
Fig. 5. (a) Observed structure of 11. (b) Optimized structure of 11opt [17]. (c)
Optimized structure of 11Me [17].
bonds of a phosphaalkene (RP@CR2) exhibit high p-character and
its lone pair dominantly consists of 3s orbital of the phosphorus
atom, since a phosphorus atom has a tendency of keeping its
intrinsic configuration of valence electrons, (3s)2(3p)3 [19].
Although the lone pair of PPh3 should dominantly consist of 3s
orbital of the phosphorus atom, the widened C–P–C angles than
90° due to the steric repulsion between the phenyl groups should
enhance the p-character of the lone pair of PPh3. Due to the less
hindered situation of the phosphorus atom of a phosphaalkene as
compared with PPh3, the lone pair of a phosphaalkene exhibit
higher s-character than that of PPh3. Thus, the relatively large 1JPRh
value of 13 should reflect the bonding properties of its P@C unit.
On the other hand, the 1JPRh coupling constant of 11 (1JPRh = 122 Hz)
is similar to or slightly smaller than that of 14 (1JPRh = 127.3 Hz),
suggesting the higher p-character of the P–Rh bond of 11 than that
of 14. That is, the P–Rh bond should consist of sp2-orbital of the
phosphorus atom, suggesting that the lone pair of the phosphorus
atom should exhibit high p-character and it should take part in the
*
of Dip and Mes . In both cases of 11 and 13, the lengths of the Rh–
CO bonds located at the trans-position of the phosphorus atom
[1.943(4) Å for 11, 1.933(5) for 13] are longer than those located
at the trans-position of the nitrogen atom [1.852(4) Å for 11 and
1.844(5) Å for 13], suggesting the effective trans-influence of the
coordinated phosphorus atom. Thus, it should be of great note that
the two carbonyl groups on the rhodium center should be in non-
equivalent situation in both cases of 11 and 13, indicating the
expectation of the novel reactivity of the rhodium–carbonyl com-
plexes. In addition, the trans-influence of the phosphorus atom of
11 should be slightly stronger than that of 13 on the basis of their
trans-C„O bond lengths [1.106(4) Å for 11, 1.131(5) Å for 13] (Figs.
5–7).
The structural and electronic features of 11 and 13 in solution
should be discussed on the basis of their NMR spectra. In 31P
NMR spectrum, 11 showed a surprisingly low-field shifted signal
1
at dP = 91.9 with JPRh = 122 Hz, in contrast to those of rhodium–
1
phosphine complexes (e.g., dP = 25.3 with JPRh = 127.3 Hz for
p
-conjugation on the imino–phosphido ligand of 11.
[RhCl(PPh3)(CO)2] (14)) [18], indicating the sp2-character of the
phosphorus atom of 11. On the other hand, rhodium complex 13
In 13C NMR spectra, 11 showed two signals assignable to the
carbonyl groups at dC = 185.7 (1JRhC = 62.6 Hz, JCP = 97.3 Hz) and
dC = 191.9 (1JRhC = 67.1 Hz, 2JCP = 21.9 Hz). The former signal should
be assignable to the CO group located at the trans-position of the
phosphorus atom on the basis of the reported JCP values of
[RhCl(PPh3)(CO)2] (14, dC = 183.0, JCP = 16.3 Hz for cis-CO for
2
1
showed a characteristic signal at dP = 158.6 with JPRh = 157 Hz,
which is in the considerably low-field region as compared with
that of 14 reflecting the P@C double bond character but in a region
higher than that of precursor 12.
2
2
1
2
The larger JPRh coupling constant of 13 (1JPRh = 157 Hz) than
PPh3, dC = 183.3, JCP = 123.4 Hz for trans-CO for PPh3) [18]. The
1
1
that of [RhCl(PPh3)(CO)2] (14, JPRh = 127.3 Hz) [18] should be due
smaller JRhC value of the trans-CO for the phosphorus atom than
to the high s-character of the P–Rh bond of 13, which may consist
that for the nitrogen atom should indicates the trans-influence of
of the lone-pair of the phosphorus atom. Generally, the
r
and
p
the phosphorus atom. Similarly, the 13C NMR data for the CO

430
T. Sasamori et al. / Polyhedron 29 (2010) 425–433
O2
C4 C5
O1
Rh
R1
R2
E1
C1
E2
C3
C2
11
11opt 11Me
13
13opt 13Me
2.2665(11)
2.080(3)
1.768(3)
1.424(4)
1.432(4)
1.308(4)
2.066(4)
2.2261(12)
1.374(6)
1.435(7)
1.428(7)
1.666(5)
Rh–E1/Å
Rh–E2/Å
E1–C1/Å
C1–C2/Å
C2–C3/Å
C3–E2/Å
2.300 2.349
2.122 2.163
1.767 1.818
1.431 1.424
1.432 1.450
1.308 1.289
2.111 2.088
2.269 2.271
1.367 1.359
1.448 1.451
1.421 1.416
1.675 1.685
1.852(4)
1.943(4)
1.142(4)
1.106(4)
1.933(5)
1.844(5)
1.131(5)
1.143(6)
Rh–C4/Å
Rh–C5/Å
C4–O1/Å
C5–O2/Å
1.861 1.848
1.931 1.932
1.152 1.153
1.150 1.151
1.943 1.926
1.860 1.871
1.146 1.149
1.153 1.153
717º
720º
Σ*
717º
686º
720º
712º
Fig. 7. Summary of observed and optimized structural parameters of 11, 11opt, 11Me, 13, 13opt and 13Me [17]. *The sum of internal angles of the Rh–P–C–C–C–N six-membered
ring skeleton.
groups of 13 were dC = 179.8 (1JRhC = 65.4 Hz, 2JCP = 131.5 Hz, trans-
CO for the phosphorus atom) and dC = 189.9 (1JRhC = 58.1 Hz,
can work as a catalyst for hydrosilylation probably due to the
trans-effect of the phosphorus atom promoting the initial elimina-
tion of the trans-CO group for the phosphorus atom.
1
2JCP = 20.4 Hz, cis-CO for the phosphorus atom). The JRhC value of
the trans-CO for the phosphorus atom is unexpectedly larger than
that for the nitrogen atom, though the results of X-ray crystallo-
graphic analysis of 13 indicate the trans-influence of the phospho-
rus atom in the crystalline state. The reason for the relatively large
1JRhC value is not clear at present.
Preliminarily, we have performed the reaction of cyclohexenone
with triethylsilane in the presence of a catalytic amount of 11 in
the expectation that 11 can promote 1,4-hydrosilylation reaction
even though 11 has CO groups on the rhodium atom. As a result,
the treatment of cyclohexanone with 3 eq. of triethylsilane in the
presence of 0.5 mol% of 11 in benzene under reflux conditions for
4 h afforded the corresponding silylenolate 17 in an almost quan-
titative yield (Scheme 9) [20]. Thus, it was demonstrated that 11
3. Conclusion
We have designed novel P,N-chelating monovalent and biden-
tate ligands with an sp2-hybridized phosphorus atom and suc-
ceeded in the synthesis of their rhodium–carbonyl complexes.
The structural parameters of 11 and 13 suggested the effective
trans-influence of their phosphorus atom. Interestingly, rhodium
complexes 11 and 13, which are isomers to each other and bear
imino–phosphido and phosphaalkenyl-anilido ligands 7 and 8,
respectively, exhibited noticeable difference between their elec-
tronic properties on the basis of X-ray crystallographic and spec-
troscopic analyses. The preliminary demonstration using 11
toward catalytic hydrosilylation suggested that the imino–phosph-
ido ligand 7 should be a possibly unique and attractive ligand for
transition metals with strong trans-influence due to the sp2-
hybridized phosphorus atom. Further investigations on the synthe-
sis of other transition metal complexes bearing such P,N-chelating
ligands having an sp2-phosphorus atom and the catalytic reactions
using 11 and 13 are currently in progress.
OC CO
Rh
Mes*
Dip
P
N
(0.5 mol%)
O
OSiEt3
11
4. Experimental
Et3SiH
+
benzene, reflux
4.0 h
4.1. General procedure
17
All experiments were performed under an argon atmosphere
unless otherwise noted. All solvents were purified by standard
Scheme 9.

T. Sasamori et al. / Polyhedron 29 (2010) 425–433
431
methods and then dried by using an Ultimate Solvent System
(Glass Contour Company) [21]. All solvents used in the reactions
and spectroscopy were dried by using a potassium mirror. 1H
NMR (300 MHz) and 13C NMR (75 MHz) spectra were measured
in CDCl3 or C6D6 with a JEOL JNM AL-300 spectrometer. Signals
due to CHCl3 (7.25 ppm) and C6D5H (7.15 ppm) were used as ref-
erences in 1H NMR, and those due to CDCl3 (77 ppm) and C6D6
(128 ppm) were used in 13C NMR. Multiplicity of signals in 13C
NMR spectra was determined by DEPT and CH-COSY techniques.
31P NMR (120 MHz) spectra were measured in CDCl3 or C6D6
with JEOL AL-300 spectrometer using 86% H3PO4 in water
(0 ppm) as an external standard. All the P–H coupling constants
were determined on the basis of both 1H and non-decoupled 31P
NMR spectra. High resolution mass spectral data were obtained
on a JEOL JMS-700 spectrometer (FAB) or a Bruker microTOF
(ESI, APPI-TOF). Wet column chromatography (WCC) was per-
formed with Wakogel C-200. All melting points were determined
on a Yanaco micro melting point apparatus and were uncor-
rected. Elemental analyses were performed by the Microanalyti-
cal Laboratory of the Institute for Chemical Research, Kyoto
University.
4.1.2. Diarylphosphine 19
To a diethyl ether solution (10 mL) of 18 (123 mg, 0.267 mmol)
was added lithium aluminum hydride (10 mg, 0.27 mmol) at 0 °C.
The reaction mixture was gradually warmed up to room tempera-
ture and stirred for 30 min. Ethyl acetate was added to the reaction
mixture for quench. After removal of the solvent under the reduced
pressure, the crude product was dissolved in hexane and then fil-
tered through CeliteÒ. The purification of the filtrate with WCC
(hexane/ether = 20/1) gave 19 (98 mg, 0.23 mmol, 85%). 19: pale
yellow liquid; 1H NMR (300 MHz, CDCl3, 298 K) d 1.38 (s, 9H),
1.42 (s, 9H), 1.51 (s, 9H), 4.09–4.24 (m, 4H), 5.86 (dd, J = 4.0,
7.7 Hz, 1H), 6.12 (d, JPH = 241.6 Hz, 1H), 6.28 (d, J = 4.2 Hz, 1H),
6.97 (dpt, J = 1.1, 7.7 Hz, 1H), 7.15 (pt, J = 7.5 Hz, 1H), 7.51–7.55
(m, 3H); 13C{1H} NMR (75 MHz, CDCl3, 298 K) d 31.5 (CH3), 33.5
(CH3), 35.3 (C), 38.6 (C), 65.4 (CH2), 65.6 (CH2), 102.4 (CH,
JPC = 20.3 Hz), 122.6 (CH), 125.4 (CH), 127.0 (CH), 127.6 (C), 128.0
(C), 128.8 (CH), 132.4 (CH), 138.2 (C, d, JPC = 16.5 Hz), 139.8 (C, d,
JPC = 23.5 Hz), 150.8 (C); 31P{1H} NMR (120 MHz, CDCl3, 298 K) d
ꢀ73.9. High-resolution MS (FAB): m/z Calc. for C27H39O2P:
426.2688. Found: 426.2696 ([M]+).
4.1.3. Ketophosphine 20
4.1.1. Chlorophosphine 18 (Scheme 10)
To a THF solution (8 mL) of 14 (152
n-butyllithium (1.51 M hexane solution, 0.66 mL, 1.0 mmol) at
An acetone solution (50 mL) of 19 (780 mg, 1.83 mmol) and
p-toluenesulfonic acid monohydrate (32 mg, 0.18 mmol) was
refluxed for 10 h. After the removal of the solvent under the re-
duced pressure, the purification of the crude product with WCC
(hexane) gave 20 (523 mg, 1.37 mmol, 75%). 20: yellow liquid;
1H NMR (300 MHz, CDCl3, 298 K) d 1.37 (s, 9H), 1.45 (s, 18H),
lL, 1.0 mmol) was added
ꢀ78 °C. After stirring at ꢀ78 °C for 30 min,
a THF solution
*
(8 mL) of Mes PCl2 (347 mg, 1.00 mmol) was added. The reaction
mixture was gradually warmed up to room temperature and stir-
red for 3 h. After the removal of the solvent under the reduced
pressure, the crude product was dissolved in hexane and then fil-
tered through CeliteÒ. The filtrate was purified with WCC (hex-
ane/ether = 20/1) to afford 18 (271 mg, 0.588 mmol, 74%). 18:
pale yellow liquid; 1H NMR (300 MHz, CDCl3, 298 K) d 1.33 (s,
9H), 1.35 (s, 18H), 3.58–3.66 (m, 2H), 3.87–3.93 (m, 2H), 4.05
(s, 1H), 7.29–7.35 (m, 2H), 7.39 (s, 2H), 7.47–7.52 (m, 1H),
7.83–7.87 (m, 1H); 13C{1H} NMR (75 MHz, CDCl3, 298 K) d 31.1
(CH3), 33.8 (CH3), 33.9 (CH3), 34.8 (C), 39.9 (C), 84.8 (CH2),
1
5.97 (dd, J = 3.7, 7.3 Hz, 1H), 6.51 (d, JPH = 255.3 Hz, 1H), 7.18
(pt, J = 7.3 Hz, 1H), 7.29 (pt, J = 7.5 Hz, 1H), 7.53 (s, 1H), 7.54 (s,
4
1H), 7.78 (ddd, J = 1.4, 3.1, 7.5 Hz, 1H), 10.25 (d, JPH = 2.3 Hz,
1H); 13C{1H} NMR (75 MHz, CDCl3, 298 K) d 31.3 (CH3), 33.3
(CH3), 35.2 (C), 38.4 (C), 119.4 (C), 122.6 (CH), 126.6 (CH), 128.5
(C, d, JPC = 29.0 Hz,), 132.8 (CH), 132.9 (CH), 134.0 (CH), 136.2 (C,
d, JPC = 9.3 Hz), 146.1 (C, d, JPC = 34.6 Hz), 150.9 (C), 193.2 (CH, d,
JPC = 4.3 Hz); 31P{1H} NMR (120 MHz, CDCl3, 298 K) d ꢀ60.1.
High-resolution MS (FAB): m/z Calc. for C25H35OP: 382.2426.
Found: 382.2426 ([M]+).
3
85.1 (CH2), 100.0 (CH, d, JPC = 7.5 Hz), 124.0 (CH), 125.9 (CH),
128.7 (CH), 128.9 (CH), 131.9 (CH, d, JPC = 8.3 Hz), 138.7 (CH, d,
JPC = 22.5 Hz), 139.0 (C), 139.8 (C), 152.8 (C), 161.1 (C, d,
4.1.4. Compound 9
JPC = 20.3 Hz); 31P{1H} NMR (120 MHz, CDCl3, 298 K)
d
77.4.
To a toluene solution (5 mL) of 20 (50 mg, 0.13 mmol) was
High-resolution MS (ESI): m/z Calc. for C27H39O2PCl: 461.2376.
added DipNH2 (250
lL, 1.3 mmol) and trifluoroborane diethyl
Found: 461.2334 ([M+H]+).
etherate (14 L, 0.11 mmol). After the reflux for 10 h, the solvent
l
Scheme 10.

432
T. Sasamori et al. / Polyhedron 29 (2010) 425–433
was removed under the reduced pressure. The purification of the
crude product with WCC (hexane) gave 9 (69 mg, 0.12 mmol,
98%) [12].
ature was raised up to room temperature and then the reaction
mixture was stirred for 30 min. To the reaction mixture was added
trimethylsilyl chloride (91
30 min. To the reaction mixture was added n-butyllithium
(1.51 M hexane solution, 480 L, 0.72 mmol). To the reaction mix-
lL, 0.72 mmol) and keep stirring for
4.1.5. Rhodium complex 11
l
To a C6H6 solution (0.70 mL) of 9 (54 mg, 0.10 mmol) and
[RhCl(CO)2]2 (19 mg, 0.049 mmol) was added triethylamine
(140 lL, 1.0 mmol). The reaction mixture was heated at 60 °C for
ture was added 16 at ꢀ78 °C and stirred for 3.0 h. After the removal
of the solvent under the reduced pressure, the crude product was
dissolved in hexane and then filtered through CeliteÒ. The filtrate
was purified with WCC (hexane) to afford 12 (85 mg, 0.16 mmol,
22%). 12: yellow crystals, mp 192 °C (decomp.); 1H NMR
6.0 h. The solvent was removed in vacuo. The purification of the
crude product with CeliteÒ filtration (hexane) gave 11 (69 mg,
0.12 mmol, 98%). 11: deep purple crystals; m.p. 118 °C (decomp.);
3
(300 MHz, CDCl3, 298 K) d 1.23 (d, JHH = 6.9 Hz, 6H), 1.30 (d,
3
1H NMR (300 MHz, C6D6, 298 K) d 0.98 (d, JHH = 7.2 Hz, 6H), 1.32
3JHH = 6.9 Hz, 6H), 1.45 (s, 9H), 1.63 (s, 18H), 3.23 (sept,
3
3
3
(d, JHH = 7.2 Hz, 6H), 1.33 (s, 9H), 1.77 (s, 18H), 3.36 (sept,
3JHH = 6.9 Hz, 2H), 6.36 (d, JHH = 8.0 Hz, 1H), 6.73 (t, JHH = 7.4 Hz,
3JHH = 6.9 Hz, 6H), 6.61–6.67 (m, 1H), 6.72–6.79 (m, 1H), 7.07–
7.28 (m, 5H), 7.85 (s, 1H), 7.86 (s, 1H), 8.10 (dd, J = 3.3, 5.1 Hz,
1H); 13C{1H} NMR (75 MHz, C6D6, 298 K) d 23.0 (CH3), 25.1
(CH3), 28.4 (CH), 31.4 (CH3), 34.2 (CH3), 35.3 (C), 40.2 (C), 120.1
(CH), 123.8 (CH), 124.3 (CH, d, JPC = 8.0 Hz), 125.1 (C, d,
JPC = 16.1 Hz), 127.4 (C), 128.5 (CH), 129.0 (CH, d, JPC = 9.3 Hz),
138.2 (CH, d, JPC = 4.4 Hz), 139.7 (C), 150.7 (C, d, JPC = 7.4 Hz),
151.8 (C, d, JPC = 2.5 Hz), 157.1 (C, d, JPC = 6.2 Hz), 161.1 (C), 161.6
(CH, d, JPC = 16.1 Hz), 185.7 (C, dd, J = 62.6, 97.3 Hz), 191.9 (C, dd,
J = 21.9, 67.1 Hz); 31P{1H} NMR (120 MHz, C6D6, 298 K) d 91.9 (d,
1H), 6.93 (d, JPH = 20.7 Hz, 1H), 7.03 (t, JHH = 7.4 Hz, 1H), 7.17 (d,
3
3JHH = 8.0 Hz, 1H), 7.33–7.42 (m, 3H), 7.57 (s, 2H), 8.51 (d,
2JPH = 23.7 Hz, 1H); 13C{1H} NMR (75 MHz, CDCl3, 298 K) d 22.8
(CH3), 25.1 (CH3), 28.4 (CH), 31.4 (CH3), 33.8 (CH3), 33.9 (CH3),
35.0 (C), 38.3 (C), 112.5 (CH), 116.8 (CH), 121.9 (CH), 123.9 (CH),
124.3 (C, d, JPC = 3.1 Hz), 127.5 (CH), 128.6 (C, d, JPC = 8.0 Hz),
132.0 (C, d, JPC = 17.9 Hz), 135.0 (C), 139.9 (C, d, JPC = 53.7 Hz),
146.5 (C), 147.4 (C), 149.9 (C), 154.1 (C), 176.6 (CH, d,
JPC = 38.9 Hz); 31P{1H} NMR (120 MHz, CDCl3, 298 K) d 241.2;
High-resolution MS (EI): m/z Calc. for C37H52NP: 541.3837. Found:
541.3833 ([M]+); Anal. Calc. for C37H52NP: C, 82.02; H, 9.67; N, 2.59.
Found: C, 82.00; H, 9.74; N, 2.54%.
1JPRh = 122 Hz); IR(KBr) CO = 1988.7, 2045.78 cmꢀ1; High-resolu-
m
tion MS (FAB): m/z Calc. for C39H51O2NPRh: 699.2712. Found:
699.2724 ([M]+); Anal. Calc. for C39H51O2NPRh: C, 66.94; H, 7.35;
N, 2.00. Found: C, 66.85; H, 7.46; N, 2.05%.
4.1.9. Rhodium complex 13
To a C6H6 solution (0.70 mL) of 12 (20 mg, 0.037 mmol) and
[RhCl(CO)2]2 (7.3 mg, 0.019 mmol) was added triethylamine
4.1.6. Diarylamine 15
To DipNH2 (500
Pd(OAc)2 (18 mg, 0.080 mmol), NaO(t-Bu) (443 mg, 4.62 mmol),
DPEphos (64 mg, 0.12 mmol) and 1 (500 L, 3.3 mmol). The reac-
l
L, 2.65 mmol) in toluene (6 mL) was added
(50 lL, 0.37 mmol) at room temperature. The reaction mixture
was heated at 60 °C for 4.0 h. The solvent was removed in vacuo.
The purification of the crude product with CeliteÒ filtration (hex-
ane) gave 13 (29 mg, 0.036 mmol, 97%). 13: purplish red crystals,
mp 120 °C (decomp.); 1H NMR (300 MHz, C6D6, 298 K) d 1.03 (d,
l
tion mixture was stirred at 120 °C for 8.0 h. The solvent was re-
moved in vacuo. The purification of the crude product with
CeliteÒ filtration (hexane) and HPLC (CHCl3) afforded 15 (648 mg,
1.99 mmol, 75%). 15: pale yellow liquid; 1H NMR (300 MHz, CDCl3,
3
3JHH = 7.2 Hz, 6H), 1.28 (s, 9H), 1.46 (d, JHH = 7.2 Hz, 6H), 1.73 (s,
3
18H), 3.29 (sept, JHH = 7.2 Hz, 6H), 6.47–6.51 (m, 1H), 6.77–6.80
3
298 K) d 1.16 (d, JHH = 6.9 Hz, 6H), 1.21 (d, 3JHH = 6.9 Hz, 6H), 3.19
(m, 1H), 6.85–6.91 (m, 1H), 7.02–7.05 (s, 1H), 7.22 (s, 3H), 7.74
3
3
2
(sept, JHH = 6.9 Hz, 2H), 4.10–4.21 (m,4H), 6.04 (s, 1H), 6.23 (d,
(d, JHH = 3.3 Hz, 2H), 8.42 (d, JPH = 17.7 Hz, 1H); 13C{1H} NMR
(75 MHz, C6D6, 298 K) d 24.5 (CH3), 24.8 (CH3), 27.9 (CH), 30.9
(CH3), 34.9 (CH3), 35.4 (C), 39.4 (C), 115.1 (CH), 117.5 (CH),
1213.3 (CH, d, JPC = 9.2 Hz), 124.0 (CH), 124.7 (CH), 126.3 (CH),
129.3 (C, d, JPC = 27.8 Hz), 129.9 (CH), 134.1 (CH, d, JPC = 24.1 Hz),
141.7 (C), 149.4 (C), 153.3 (C), 155.4 (CH, d, JPC = 40.1 Hz), 156.7
(C), 163.0 (C), 179.8 (C, dd, J = 65.4, 131.5 Hz), 189.9 (C, dd,
J = 20.4, 58.1 Hz); 31P{1H} NMR (120 MHz, C6D6, 298 K) d 158.6
3
JHH = 8.4 Hz, 1H), 6.38 (s, 1H), 6.75 (t, JHH = 7.5 Hz, 1H), 7.10 (t,
3
3JHH = 6.6 Hz, 1H), 7.24–7.32 (m, 3H), 7.43 (d, JHH = 7.8 Hz, 1H);
13C{1H} NMR (75 MHz, CDCl3, 298 K) d 22.7 (CH3), 24.5 (CH3),
28.1 (CH), 64.7 (CH2), 103.4 (CH), 112.4 (CH), 116.9 (CH), 120.6
(C), 123.6 (CH), 126.7 (CH), 127.0 (CH), 129.7 (C), 135.5 (C), 146.4
(C), 146.7 (C); High-resolution MS (EI): m/z Calc. for C21H27O2N:
325.2042. Found: 325.2046 ([M]+).
1
(d, JPRh = 157 Hz). High-resolution MS (ESI): m/z Calc. for
4.1.7. Diarylamine 16
C38H52ONPRh: 672.2836 ([M+H]+). Found: 682.2841 ([MꢀCO+H]+).
A toluene solution (10 mL) of 15 (197 mg, 0.605 mmol) and p-
toluenesulfonic acid monohydrate (60 mg, 0.31 mmol) was stirred
for 1.0 h. To the reaction mixture was added H2O and extracted
with toluene. The organic layer was dried with MgSO4. The solvent
was removed under the reduced pressure to afford 16 (165 mg,
0.586 mmol, 91%). 16: yellow liquid; 1H NMR (300 MHz, CDCl3,
4.1.10. Hydrosilylation reaction
To a benzene solution (2 mL) of rhodium complex 11 (3.5 mg,
5.0
lmol) was added 2-cyclohexen-1-one (96
lL, 1.0 mmol) and
Et3SiH (480
lL, 3.0 mmol). The reaction mixture was heated at re-
flux temperature for 4 h. The solvent was removed in vacuo. The
residue was purified with WCC (hexane) to afford silylenolate 17
(210 mg, 0.99 mmol, 99%) [23].
3
3
298 K) d 1.11 (d, JHH = 6.9 Hz, 6H), 1.16 (d, JHH = 6.9 Hz, 6H),
3
3
3.07 (sept, JHH = 6.9 Hz, 2H), 6.23 (d, JHH = 8.7 Hz, 1H), 6.72 (t,
3JHH = 7.2 Hz, 1H), 7.20–7.36 (m, 3H), 7.56 (d, JHH = 7.8 Hz, 1H),
3
9.57 (s, 1H), 9.97 (s, 1H); 13C{1H} NMR (75 MHz, CDCl3, 298 K) d
23.0 (CH3), 24.5 (CH3), 28.4 (CH), 112.6 (CH), 115.7 (CH), 118.0
(C), 123.9 (CH), 128.0 (CH), 133.4 (C), 135.6 (CH), 136.2 (CH),
147.4 (C), 151.0 (C), 194.3 (C); High-resolution MS (EI): m/z Calc.
for C19H23ON: 281.1780. Found: 281.1779 ([M]+).
4.2. X-ray crystallographic analysis
X-ray crystallographic analysis of 9, 11, 12 and [13ꢁC6H6]. The
intensity data were collected on a Rigaku/MSC Mercury CCD dif-
fractometer with graphite monochromated Mo
Ka radiation
(k = 0.71070 Å). Single crystals suitable for X-ray analysis were ob-
tained by slow recrystallization from hexane/THF (for 9 and 12),
benzene (for 11 and [13ꢁC6H6]). The single crystals were mounted
4.1.8. Compound 12 [22]
To a THF solution (10 mL) of Mes PH2 (200 mg, 0.72 mmol) was
added n-butyllithium (1.51 M hexane solution, 480
at ꢀ78 °C. After stirring at ꢀ78 °C for 15 min, the reaction temper-
*
l
L, 0.72 mmol)
on a glass fiber. The structures were solved by a direct method (SIR-
97 [24]) and refined by full-matrix least-squares procedures on F2

T. Sasamori et al. / Polyhedron 29 (2010) 425–433
[3] (a) (For examples, see:) P.L. Floch, Coord. Chem. Rev. 250 (2006) 627;
433
for all reflections (SHELXL-97 [25]). All hydrogen atoms were placed
using AFIX instructions, while all other atoms were refined aniso-
tropically. Crystal data: 9: C37H52NP, M = 541.77, T = 103(2) K,
monoclinic, P21/n (no. 14), a = 9.8299(3) Å, b = 26.7647(6) Å,
c = 13.2744(3) Å, b = 108.2538(12)°, V = 3316.67(15) Å3, Z = 4,
(b) F. Ozawa, S. Kawagishi, T. Ishiyama, M. Yoshifuji, Organometallics 23
(2004) 1325;
(c) F. Mathey, Angew. Chem., Int. Ed. 42 (2003) 1578;
(d) M. Okazaki, A. Hayashi, C.F. Fu, S.T. Liu, F. Ozawa, Organometallics 28
(2009) 902;
(e) J. Yorke, L. Wan, A.B. Xia, W.J. Zheng, Tetrahedron Lett. 48 (2007) 8843;
(f) C. Müller, L.G. López, H. Kooijman, A.L. Spek, D. Vogt, Tetrahedron Lett. 47
(2006) 2017.
Dcalc = 1.085 g cmꢀ3 = 0.107 mmꢀ1, 2hmax. = 51.0, 29226 mea-
, l
sured reflections, 6173 independent reflections (Rint = 0.0520),
420 refined parameters, GOF = 1.049, R1 = 0.0447 and wR2 =
[4] (a) (For reviews, see:) L. Weber, Chem. Rev. 92 (1992) 1839;
(b) P.P. Power, Chem. Rev. 99 (1999) 3463;
0.1150 [I > 2r(I)], R1 = 0.0710 and wR2 = 0.1247 [for all data], larg-
(c) N. Tokitoh, J. Organomet. Chem. 611 (2000) 217;
(d) P.P. Power, J. Organomet. Chem. 689 (2004) 3904;
(e) T. Sasamori, N. Tokitoh, Dalton Trans. (2008) 1395.
[5] (a) K. Dimroth, P. Hoffmann, Angew. Chem., Int. Ed. 3 (1964) 384;
(b) G. Becker, Z. Anorg. Allg. Chem. 423 (1976) 242;
(c) T.C. Klebach, R. Lourens, F. Bickelhaupt, J. Am. Chem. Soc. 100 (1978) 4886.
[6] (The first stable diphosphene has been synthesized and isolated by Yoshifuji
et al., see:) M. Yoshifuji, I. Shima, N. Inamoto, K. Hirotsu, T. Higuchi, J. Am.
Chem. Soc. 103 (1981) 4587.
[7] T. Sasamori, T. Matsumoto, N. Takeda, N. Tokitoh, Organometallics 26 (2007)
3621.
[8] J. Grundy, B. Donnadieu, F. Mathey, J. Am. Chem. Soc. 128 (2006) 7716.
[9] F. Basuli, J. Tomaszewski, J.C. Huffman, D.J. Mindiola, J. Am. Chem. Soc. 125
(2003) 10170.
est difference in peak and hole 0.375 and ꢀ0.559 e Åꢀ3. 11:
ꢀ
C39H51NO2PRh, M = 699.69, T = 103(2) K, triclinic, P1 (no. 2),
a = 9.149(3) Å, b = 10.890(4) Å, c = 20.211(7) Å,
b = 101.609(3)°,
= 106.9868(16)°, V = 1844.4(10) Å3, Z = 2, Dcalc
1.260 g cmꢀ3 = 0.538 mmꢀ1
2hmax. = 51.0, 16107 measured
a = 97.934(4)°,
c
=
,
l
,
reflections, 6795 independent reflections (Rint = 0.0378), 410 re-
fined parameters, GOF = 0.969, R1 = 0.0387 and wR2 = 0.1190
[I > 2r(I)], R1 = 0. 0483 and wR2 = 0.1337 [for all data], largest dif-
ference in peak and hole 0.602 and ꢀ0.771 e Åꢀ3. 12: C37H52NP,
ꢀ
M = 541.77, T = 103(2) K, triclinic, P1 (no. 2), a = 9.484(3) Å, b =
[10] (a) (There have been
a few reports on the theoretical calculations for a
13.720(4) Å,
c
c = 13.737(4) Å,
a
= 93.542(2)°,
b = 99.935(3)°,
= 109.895(4)°, V = 1641.6(9) Å3, Z = 2, Dcalc = 1.096 g cmꢀ3
, l =
phosphorus analogue of a Schiff-base type ligand (phosphaalkenylphenoxide)
from the viewpoint of catalytic activities, see:) M.S.W. Chan, L.Q. Deng, T.
Ziegler, Organometallics 19 (2000) 2741;
(b) T.Z. Zhang, D.W. Guo, S.Y. Jie, W.H. Sun, T. Li, X.Z. Yang, J. Polym. Sci.,
Polym. Chem. 42 (2004) 4765;
0.108 mmꢀ1, 2hmax. = 51.0, 11551 measured reflections, 5989 inde-
pendent reflections (Rint = 0.0329), 390 refined parameters,
GOF = 1.069, R1 = 0.0515 and wR2 = 0.1094 [I > 2r(I)], R1 = 0. 0746
(c) (Recently, anilido-phosphiniimine complexes have been synthesized,
see:)K.D. Conroy, W.E. Piers, M. Parvez, J. Organomet. Chem. 693 (2008) 834.
[11] A.S. Ionkin, W.J. Marshall, B.M. Fish, M.F. Schiffhauer, F. Davidson, C.N.
McEwen, D.E. Keys, Organometallics 26 (2007) 5050.
[12] N. Tokitoh, T. Matsumoto, T. Sasamori, Heterocycles 76 (2008) 981.
[13] M. Yoshifuji, K. Toyota, I. Matsuda, T. Niitsu, N. Inamoto, K. Hirotsu, T. Higuchi,
Tetrahedron 44 (1988) 1363.
and wR2 = 0.1235 [for all data], largest difference in peak and hole
0.248 and ꢀ0.259 e Åꢀ3. [13ꢁC6H6]: C45H57NO2PRh, M = 777.80,
T = 113(2) K, orthorhombic, P212121 (no. 19), a = 9.5822(5) Å,
b = 16.9794(11) Å, c = 24.7695(16) Å, V = 4030.0(4) Å3, Z = 4,
Dcalc = 1.282 g cmꢀ3 = 0.500 mmꢀ1, 2hmax. = 51.0, 35424 mea-
, l
[14] (a) (For examples, see:) Y. Yokoyama, K. Takahashi, Bull. Chem. Soc. Jpn. 60
(1987) 3485;
sured reflections, 7492 independent reflections (Rint = 0.0802),
452 refined parameters, GOF = 1.192, R1 = 0.0498 and wR2 =
(b) E. Rivard, A.D. Sutton, J.C. Fettinger, P.P. Power, Inorg. Chim. Acta 360
(2007) 1278.
[15] M. Yoshifuji, K. Toyota, N. Inamoto, Tetrahedron Lett. 26 (1985) 1727.
[16] SDBSWeb: <http://riodb01.ibase.aist.go.jp/sdbs/> (National Institute of
Advanced Industrial Science and Technology, April 2009).
0.0893 [I > 2r(I)], R1 = 0. 0629 and wR2 = 0.0963 [for all data], larg-
est difference in peak and hole 0.742 and ꢀ0.559 e Åꢀ3
.
Supplementary data
[17] All calculations were conducted using the GAUSSIAN 03 series of electronic
structure programs. The geometries were optimized with density functional
theory at the B3PW91 level using 6-31G(d) basis sets (for C, H, N, and O), 6-
311G(3d) (for P), and Lanl2DZ (for Rh). It was confirmed by frequency
calculations that the optimized structures have minimum energies.
Computation time was provided by the Super Computer Laboratory,
Institute for Chemical Research, Kyoto University.
[18] E. Rotondo, G. Battaglia, G. Giordano, F.P. Cusmano, J. Organomet. Chem. 450
(1993) 245.
[19] T. Sasamori, E. Mieda, N. Nagahora, K. Sato, D. Shiomi, T. Takui, Y. Hosoi, Y.
Furukawa, N. Takagi, S. Nagase, N. Tokitoh, J. Am. Chem. Soc. 128 (2006) 12582
(and references cited therein).
CCDC 729128, 729129, 729130, 729131 contains the supple-
mentary crystallographic data for 9, 11, 12 and [13ꢁC6H6]. These
data can be obtained free of charge via http://www.ccdc.cam.a-
c.uk/conts/retrieving.html, or from the Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44)
1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.
Acknowledgment
[20] Some control experiments have been examined as follows: (i) Reaction of 2-
cyclohexen-1-one (96
benzene (2 mL) in the absence of any catalysis under the reflux conditions for
4 h. (ii) Reaction of 2-cyclohexen-1-one (96 L, 1.0 mmol) with Et3 SiH (480
L, 3.0 mmol) in benzene (2 mL) in the presence of ligand 9 (2.7 mg, 5.0 mol)
under the reflux conditions for 4 h. (iii) Reaction of 2-cyclohexen-1-one (96 L,
L, 3.0 mmol) in benzene (2 mL) in the presence
mol) under the reflux conditions for 4 h. All of
lL, 1.0 mmol) with Et3 SiH (480 lL, 3.0 mmol) in
This work was supported by Grant-in-Aid for Creative Scientific
Research (No. 17GS0207), Science Research on Priority Areas (No.
20036024, ‘‘Synergy of Elements”), and the Global COE Program
(‘‘Integrated Materials Science”, Kyoto University) from Ministry
of Education, Culture, Sports, Science and Technology, Japan.
l
l
l
l
1.0 mmol) with Et3 SiH (480
of [RhCl(CO)2]2 (1.0 mg, 2.5
l
l
these control reactions were unsuccessful with the quantitative recover of 2-
cyclohexen-1-one.
[21] A.B. Pangborn, M.A. Giardello, R.H. Grubbs, R.K. Rosen, F.J. Timmers,
Organometallics 15 (1996) 1518.
References
[22] (For the recent development on phospha-Peterson reactions, see:) M. Yam, J.H.
Chong, C.W. Tsang, B.O. Patrick, A.E. Lam, D.P. Gates, Inorg. Chem. 45 (2006)
5225 (and references cited therein).
[23] I. Ojima, R.J. Donovan, N. Clos, Organometallics 10 (1991) 2606.
[24] A. Altomare, M.C. Burla, M. Camalli, G.L. Cascarano, C. Giacovazzo, A.
Guagliardi, A.G.G. Moliterni, G. Polidori, R. Spagna, J. Appl. Crystallogr. 32
(1999) 115.
[25] (a) G.M. Sheldrick, Acta Crystallogr., Sect. A 46 (1990) 467;
[b] G. Sheldrick, SHELX-97 Program for Crystal Structure Solution and the
Refinement of Crystal Structures, Institüt für Anorganische Chemie der
Universität Göttingen, Tammanstrasse 4, D-3400 Göttingen, Germany, 1997.
[1] (For a review see:) L. Bourget-Merle, M.F. Lappert, J.R. Severn, Chem. Rev. 102
(2002) 3031.
[2] (a) (For examples, see:) B.Y. Liu, C.Y. Tian, L. Zhang, W.D. Yan, W.J. Zhang, J.
Polym. Sci., Polym. Chem. 44 (2006) 6243;
(b) D. Zhang, G.X. Jin, L.H. Weng, F.S. Wang, Organometallics 23 (2004) 3270;
(c) X.F. Li, K. Dai, W.P. Ye, L. Pan, Y.S. Li, Organometallics 23 (2004) 1223;
(d) R. Andres, E. de Jesus, F.J. de la Mata, J.C. Flores, R. Gomez, J. Organomet.
Chem. 690 (2005) 939;
(e) J.K. Zhang, Z.F. Ke, F. Bao, J.M. Long, H.Y. Gao, F.M. Zhu, Q. Wu, J. Mol. Catal.
A 249 (2006) 31.