Synthesis, structure, and properties of extended π-conjugated systems bearing sterically crowded triarylphosphines

Article abstract of DOI:10.1016/j.jorganchem.2011.07.013

The sterically crowded triarylphosphines bearing formyl and benzoyl groups were synthesized and characterized by X-ray crystallography. The benzoyl derivative was converted to the p-quinomethane conjugated with the triarylphosphine. The McMurry coupling o

Full text of DOI:10.1016/j.jorganchem.2011.07.013

Journal of Organometallic Chemistry 696 (2011) 3307e3315
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis, structure, and properties of extended
p-conjugated systems bearing
sterically crowded triarylphosphines
1
*
Shigeru Sasaki , Kohji Sasaki, Masaaki Yoshifuji
Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai 980-8578, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
The sterically crowded triarylphosphines bearing formyl and benzoyl groups were synthesized and
characterized by X-ray crystallography. The benzoyl derivative was converted to the p-quinomethane
conjugated with the triarylphosphine. The McMurry coupling of the formyl derivative afforded the
diarylethene bearing the two sterically-crowded-triarylphosphine moieties. The cyclic voltammograms
of these compounds show reversible redox waves corresponding to the oxidation to the radical cations of
the triarylphosphines and irreversible or quasi-reversible waves corresponding to the reduction of the
Received 3 December 2010
Received in revised form
25 June 2011
Accepted 5 July 2011
Keywords:
Phosphine
acceptor moieties. The electronic and the fluorescence spectra of these
push-pull substituted derivatives, exhibit bathochromic shift typical of the extended
p
-conjugated systems, especially
-conjugated
p
p-Conjugated system
systems especially in the polar solvent, and the large Stokes shift typical of the crowded triaryl-
phosphines is enhanced by conjugation with the acceptor moiety.
Ó 2011 Elsevier B.V. All rights reserved.
Electronic spectrum
Redox properties
1. Introduction
dyes. As a fundamental strategy toward colored molecules, the
captodative or push-pull p-electronic system has long been known
The sterically crowded triarylphosphines such as tris(2,4,6-
triisopropylphenyl)phosphine (1) [1] have large bond angles
around the phosphorus and some of them are reversibly oxidized at
low potential to the stable radical cations because of the synergistic
effect of high HOMO arising from the structural change around the
phosphorus and the steric protection by the bulky aryl groups
(Chart 1) [2]. Because such a good donor molecule is expected to be
substructure of the functional materials, we synthesized crowded
triarylphosphines similar to 1 bearing donors [3], acceptors [4], and
radicals [5], and revealed their redox properties. The triar-
ylphosphine moieties generally work as reversible redox sites even
if bound to other redox sites and construct the multistep redox
systems. Among the compounds we surveyed, the sterically crow-
ded triarylphosphines bearing naphthoquinone moieties such as 2
are worth mentioning [4b]. They exhibit purple to blue color arising
from intramolecular charge transfer from the phosphine to the
naphthoquinone moieties and are expected to be the potential
candidates for the functional dyes. Being encouraged by these
results, we continued to explore the synthesis of the chromophores
bearing the triarylphosphine moieties applicable to the functional
[6] and widely applied to the functional materials such as nonlinear
optics [7] and fluorescent emitting materials [8]. They exhibit
deeper color than the parent
push-pull substitution enhances delocalization of the
p
-conjugated systems because the
-electrons
p
to make the HOMO-LUMO gap narrower, as conventionally
expressed by the neutral and twitterionic resonance structures
(Scheme 1). Herein we report synthesis, structure and properties
of the formyl and the benzoyl substituted sterically crowded tri-
arylphosphines 3 and 4, and the related compounds 5 and 6. The
formyl and the benzoyl derivatives can be regarded as typical
examples of the push-pull substituted benzenes bearing the
sterically crowded phosphinyl group as a donor. They also serve as
the key synthetic intermediates to the extended
systems. Further extended push-pull -conjugated system 5 was
synthesized from 4 with the use of the p-quinomethane structure.
The diarylethene bearing the two sterically-crowded-
p-conjugated
p
6
triarylphosphine moieties was synthesized by the McMurry
coupling of the aldehyde 3.
2. Results and discussion
2.1. Synthesis and characterization
* Corresponding author. Tel./fax: þ81 22 795 6561.
E-mail address: ssasaki@m.tohoku.ac.jp (S. Sasaki).
Present address: Department of Chemistry, The University of Alabama, Tusca-
We reported the sterically crowded triarylphosphine 7 bearing
a bromo group as a key intermediate for the synthesis of the tri-
arylphosphines bound to various functional sites [4,5]. The
1
loosa, AL 35487-0336, USA.
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.07.013

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S. Sasaki et al. / Journal of Organometallic Chemistry 696 (2011) 3307e3315
Scheme 2. Synthesis of the sterically crowded triarylphosphines bearing formyl and
benzoyl groups.
CDCl3, 296 K) chemical shifts typical of the sterically crowded
triarylphosphines (
d
ꢁ48.5 (3), ꢁ49.5 (4), ꢁ50.6 (5), ꢁ50.7, ꢁ50.9
((Z)-6), ꢁ50.9 ((E)-6), ꢁ51.5, ꢁ51.7(8), ꢁ51.9 (1) [1]). The electron
withdrawing formyl and benzoyl groups have deshielding effect as
compared with the alkenyl and alkyl groups. The diarylethene 6
bearing the two sterically-crowded-triarylphosphine moieties
exhibits two singlets with the ratio of 1/1 for the Z isomer, because
of the diastereomers arising from the helicity of the propellers
composed of the three aromatic rings on the phosphorus [2,4]. The
E form exhibits a single peak because the two triarylphosphine
moieties are separated without the intervening substituents. The
peak separation of the diastereomers was enhanced by the
measurement in C6D6
(d
ꢁ50.04, ꢁ50.25 ((Z)-6), ꢁ50.33, ꢁ50.38
((E)-6)). The carbinol 8 has two stereocenters, the helicity of the
propeller of the triarylphosphine moiety and the quaternary
carbon, and also exhibits two 31P chemical shifts with 1/1 ratio. The
1H and 13C NMR spectra of the substituents on the phosphorus
exhibit the inversion-averaged patterns typical of the triar-
ylphosphines such as 1. The two 2,4,6-triisopropylphenyl groups
gave one o-methine, one m-aromatic, and four o-methyl 1H signals
as a result of the averaging. The remaining aryl group gave one
o-methine, one m-aromatic, and two o-methyl signals. The struc-
tures of 3 and 4 were further studied by X-ray crystallography
(Figs. 1 and 2). The average bond angles and lengths around the
phosphorus of 3 (111.9ꢀ, 1.835 Å) and 4 (111.6ꢀ, 1.845 Å and 111.2ꢀ,
1.851 Å for independent molecules) are similar to those of 1 (111.5ꢀ,
1.845 Å) [1]. The dihedral angle of the least squares planes defined
by the formyl group and the aromatic ring of 3 is 1.585ꢀ, while the
benzoyl group of 4 deviates from co-planarity with the dihedral
angles as 24.28ꢀ and 29.42ꢀ.
Chart 1. Sterically crowded triarylphosphines.
bromoaryl derivative 7 was found to serve as a starting material for
the construction of the extended -conjugated systems (Scheme 2).
p
The (bromoaryl)phosphine 7 was lithiated with butyllithium,
reacted with DMF [9] and benzonitrile [10], and hydrolyzed to
afford the formyl derivative 3 and the benzoyl derivative 4,
respectively. The addition of the highly nucleophilic 4-oxide-aryl-
lithium [11], prepared by the dilithiation of 2,6-di-tert-butyl-4-
iodophenol [12], to 4 followed by hydrolysis gave the carbinol 8
(Scheme 3). The dehydration of 8 in the presence of trifluoroacetic
acid afforded the p-quinomethane 5. The McMurry coupling of 3 in
the presence of the low valent titanium generated from TiCl3 and
LiAlH4 [13] afforded an E/Z mixture (1/0.3) of the diarylethene 6.
The E/Z ratio was reversed to 0.2/1 by the irradiation with a Xe lamp
2.2. Redox properties and UVeVis and fluorescence spectra
(l > 300 nm) in benzene, but the irradiation in the polar solvents
The redox properties of the newly synthesized triar-
ylphosphines were studied by cyclic voltammetry in dichloro-
methane and tetrahydrofuran. The redox and spectral properties
are summarized in Table 1. The triarylphosphines 3, 4, 5 (Fig. 3) 8,
and 6 (Fig. 4) show the first reversible redox waves corresponding
to the oxidation of the triarylphosphines to the corresponding
radical cations. The triarylphosphines 3 and 4 show irreversible
waves corresponding to the reduction of the carbonyl moiety and 5
shows quasi-reversible redox waves corresponding to the two step
reduction of the p-quinomethane moiety. The first oxidation
such as dichloromethane lead to the formation of the radical cation
as evidenced by the purple color of the solution and the broadening
of the NMR spectra. The E/Z ratio was not changed by heating
(70 ꢀC, 15 min in C6D6), but attempted chromatographic purifica-
tion of the Z isomer lead to isomerization to give the E-rich mixture.
The newly synthesized extended
p-conjugated compounds
were characterized by conventional spectroscopy. The triar-
ylphosphines 3, 4, 5, 6, and 8 show up-fielded 31P NMR (162 MHz,
1
ox
potentials depend on the substituents in the order of
E
¼ 0.34
1/2
(formyl (3)) 0.31 (benzoyl (4)) 0.27 (p-quinomethane
>
>
(5)) > 0.22 (alkenyl (6)) > 0.19 (diarylhydroxymethyl (8)) > 0.13
(isopropyl (1)) V vs Ag/Agþ in dichloromethane) groups. The elec-
tron withdrawing substituent raises the oxidation potential. The
diarylethene 6, a mixture of the E/Z isomers as well as having two
triarylphosphine moieties, exhibits a single unresolved redox wave
with wider peak-to-peak separation.
Scheme 1. Push-pull
p-conjugated systems.

S. Sasaki et al. / Journal of Organometallic Chemistry 696 (2011) 3307e3315
3309
Scheme 3. Synthesis of the extended
p-conjugated systems bearing the sterically-crowded-triarylphosphine moieties.
The UVeVis and the fluorescence spectra were measured in n-
hexane and dichloromethane, and shown in Fig. 5 (1, 3, 4 and 6 in
dichloromethane) and Fig. 6 (5 and 8 in n-hexane), and summarized
in Table 1. The UVeVis and the fluorescence spectra of the triar-
ylphosphines reflect the extension and the push-pull substitution of
thebenzoyl groupsleads to considerableincreaseof theformalStokes
shift especially in dichloromethane. Both the absorption and the
fluorescence show bathochromic shiftin dichloromethane, especially
more than 70 nm of bathochromic shift of the fluorescence contrib-
utes large Stokes shift in dichloromethane. The p-quinomethane 5
abs
the
p-conjugated systems. The crowded triarylphosphines 1 and 8,
shows the absorption at
l
max
¼ 433 nm in n-hexane with the
which do not have conjugated substituents, show pp* absorption at
solvent effect similar to 3 and 4 and the fluorescence at
aound abslmax ¼ 330 nm and weak fluorescence upon excitation by
l
max
¼ 713 nm in n-hexane, butnonfluorescentindichloromethane
em
abs
em
l
max
at around
l
max
¼ 510 nm. The absorption shows little
(Fig. 6). The change of the UVeVis and the fluorescence spectra from
the precursor 8 to 5 indicated the formation of the -conjugated
system. The parent compounds 9 and 10a (
< 300 nm (9), lmax ¼ 366
solvent effect, while the fluorescence in dichloromethane shows
small bathochromic shift as compared with that in n-hexane. The
formal Stokes shifts of these triarylphosphines [1c] are smaller than
p
l
(25700) nm (10a) in n-hexane) also show similar spectral change
(Chart 2) [15]. The most red-shifted absorption and emission of 5
among the compounds studied in this work reflect the smallest
difference of the oxidation potential of the triarylphosphine moiety
and the reduction potential of the acceptor moiety. The abslmax of 5 is
more pyramidalized triarylphosphines such as triphenylphosphine
abs
(
l
¼ 262, emlmax ¼ 465 nm)[14]but still substantial. Similarpp
*
max
absorptions insensitive to the solvents are also observed at around
abs
l
¼ 315 nm for 3, 4, and 6. The formyl and the benzoyl deriva-
max
tives 3 and 4 show the red-shifted pp* transition responsible to the
orange color (abslmax ¼ 407 (3), 401(4) nm in dichloromethane), and
the weak fluorescence in complementarycolor (emlmax ¼ 712 (3), 710
(4) nm in dichloromethane) (Fig. 5). Introduction of the formyl and
intermediate between 10a and the push-pull p-quinomethane 10b
abs
(
l
max
¼ 419 (28200), 479 (35500) nm in toluene, 495 nm in
dichloromethane), although the intensity is weaker [16]. The diary-
lethene 6 shows the UVeVis absorption (abslmax ¼ 309, 391 nm in
dichloromethane) and the fluorescence (emlmax ¼ 653 nm in
dichloromethane) in shorter wavelength with weaker solvent effect
as compared with 3 and 4 (Fig. 5).
The wavelength and the molar extinction coefficient, and the
solvent effect of the UVeVis spectra suggest that the visible
absorptions of 3, 4, 5 and 6 have pp* character with the polar
excited state. The solvent effect of the fluorescence, the emission in
longer wavelength with lower quantum yield in the polar solvent,
suggests further enhanced polarity of the excited state or
geometrical change to more polar structure after excitation. The
large Stokes shift of the fluorescence typical of the triar-
ylphosphines is enhanced by the conjugation with the electron
withdrawing groups. The push-pull p-conjugated systems such as
3, 4, and 5 can be interpreted as a merocyanine dye and the twit-
terionic resonance structure in the excited state could contribute to
the red-shifted UVeVis spectra and the solvent effect (Scheme 4).
In addition, taking inherently ineffective
p-conjugation and the
crowded environment of the phosphorus into consideration, the
p
-
conjugated systems bearing the crowded triarylphosphine would
prefer the twisted intramolecular charge transfer state [17] with
increased dipole rather than delocalized quinoid contribution.
Fig. 1. Molecular structure of 3. Selected bond lengths (Å) and angles (ꢀ): P1eC1
1.830(4), P1eC14 1.833(4), P1eC29 1.843(4), C1eP1eC14 110.2(2), C1eP1eC29
113.5(2), C14eP1eC29 111.9(2).

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S. Sasaki et al. / Journal of Organometallic Chemistry 696 (2011) 3307e3315
Fig. 2. Molecular structure of 4. Selected bond lengths (Å) and angles (ꢀ): P1eC1 1.852(5), P1eC20 1.841(6), P1eC35 1.842(7), C1eP1eC20 108.1(3), C1eP1eC35 115.6(3),
C20eP1eC35 111.2(3), P2eC50 1.848(5), P2eC69 1.853(7), P2eC84 1.851(5), C50eP2eC69 111.3(3), C50eP2eC84 109.9(2), C69eP2eC84 112.3(3).
Magnitude of the red shift of the pp* absorption by the substitution
of the electron withdrawing group is larger than that observed in
triphenylamine (lmax ¼ 301 (26000) nm) [18] and (4-formylphenyl)
diphenylamine (lmax ¼ 230 (37000), 289 (29700), 347(39800) nm)
[19], while the enhancement of the intensity is smaller. The effect of
contributed formation of the very polar excited state to result in the
large bathochromic shift in the polar solvent.
3. Conclusion
the
p-conjugation is intermediate between the nitrogen counter-
The extended
p-conjugated systems bearing the sterically
parts and the quinone-substituted crowded triarylphosphines such
crowded triarylphosphine moieties were synthesized by using the
crowded (bromoaryl)phosphine as a key intermediate. The crow-
ded triarylphosphine moieties still work as reversible redox sites
as 2 (lmax ¼ 557 (1700) nm in dichloromethane) where the
p-
conjugated systems are separated by the twisted aromatic-ring
quinone linkage. The spectral properties of the crowded triar-
ylphosphine, the pp* absorption in longer wavelength and the
fluorescence with the large Stokes shift and low quantum yield, are
even connected to the
spectra of the triarylphosphines demonstrated that the sterically-
crowded-triarylphosphine moiety in the -conjugated systems
p-conjugated systems. The electronic
p
succeeded by the push-pull substituted
addition, the stability of the radical cation of the crowded triar-
ylphosphine and the ineffective conjugation of the phosphorus
p-conjugated systems, in
works as a good donor and the push-pull substitution enhances
bathochromic effect rather than hyperchromic effect. The large
Stokes shift of the fluorescence characteristic of the
Table 1
Redox and spectral properties of the crowded triarylphosphines.
1
3
4
5
6
8
Redox potentials in dichloromethane
1Eo1x/2/Va
0.13
0.34
0.31
0.27
0.22
0.19
Redox potentials in tetrahydrofuran
1Eo1x/2/Vb
1Erped/Vb
2Erped/Vb
0.33
0.47
ꢁ2.42
0.47
0.44
ee
ee
ꢁ2.43
ꢁ1.85
ꢁ2.87
ꢁ2.41
UVeVis absorption and fluorescence in n-hexane
abs
l
(ε)/nm
326 (14300)
318 (7900)
388 (7900)
635 (0.017)
319 (8400)
384 (8100)
639 (0.014)
361 (22600)
433 (12200)
713 (0.0057)
312 (20700)
380 (16200)
604 (0.14)
329 (13200)
515 (0.0029)
max
em
l
(f
)/nmc
502 (0.0002)
max
UVeVis absorption and fluorescence in dichloromethane
abs
l
(ε)/nm
327 (13500)
318 (8600)
407 (7800)
712 (0.0001)
318 (8700)
401 (7200)
710 (0.0002)
375 (24800)
447 (13100)
ed
309 (27000)
391 (23000)
653 (0.03)
329 (14400)
535 (0.0028)
max
em
a
l
(f
)/nmc
516 (0.0004)
max
V vs Ag/Agþ. Conditions: ca 10ꢁ3 mol Lꢁ1 in dichloromethane with 0.1 mol Lꢁ1 n-Bu4NClO4; working electrode: glassy carbon, counter electrode: Pt wire, reference
electrode: Ag/0.01 mol Lꢁ1 AgNO3 in acetonitrile with 0.1 mol Lꢁ1 n-Bu4NClO4; E1/2(ferrocene/ferrocenium) ¼ 0.17 V; scan rate: 30 mV sꢁ1; 293 K.
b
V vs Ag/Agþ. Conditions: ca 10ꢁ3 mol Lꢁ1 in tetrahydrofuran with 0.1 mol Lꢁ1 n-Bu4NClO4; working electrode: glassy carbon, counter electrode: Pt wire, reference
electrode: Ag/0.01 mol Lꢁ1 AgNO3 in acetonitrile with 0.1 mol Lꢁ1 n-Bu4NClO4; E1/2(ferrocene/ferrocenium) ¼ 0.15 V; scan rate: 30 mV sꢁ1; 293 K.
c
Excited at abslmax. Quantum yields were estimated by comparison with the reference compounds.
No fluorescence.
Not measured.
d
e

S. Sasaki et al. / Journal of Organometallic Chemistry 696 (2011) 3307e3315
3311
Fig. 3. Cyclic voltammograms of 3, 4 and 5 in tetrahydrofuran with 0.1 mol Lꢁ1 n-
Bu4NClO4. Conditions: See Table 1.
Fig. 5. UVeVis and fluorescence spectra of the triarylphosphines 1, 3, 4, and 6 in
dichloromethane. Conditions: See Table 1.
triarylphosphines is enhanced by the conjugation with the electron
withdrawing substituents and the solvent effect of the fluorescence
as well as the UVeVis absorption suggests formation of the very
polar excited state. The conventional molecular design of the
as
the residual proton of the deuterated solvent (
d) or the carbon of the deuterated solvent ( 77.0 for chloroform-d).
31P NMR chemical shifts are expressed as
downfield from external
d
downfield from external tetramethylsilane and calibrated to
d
7.25 for chloroform-
d
functional dyes composed of p-conjugated systems can be applied
d
to these newly developed triarylphosphines and it should be
mentioned that the crowded triarylphosphines not only work as
good donors, but also exhibit characteristics distinct from the
85% H3PO4. FT-ICR mass spectra were measured on a Bruker APEX
III with electrospray ionization (ESI). Melting points were measured
on a Yanagimoto MP-J3 apparatus without correction. UVeVis
spectra were measured on a Hitachi U-3210 or a Shimadzu UV-
3600 spectrometer. Fluorescence spectra were measured on
a Jasco FP-6600 spectrometer and the quantum yields were esti-
mated by comparison with the standard (4-(dicyanomethylene)-2-
methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) in methanol
as 0.43 [20] or quinine sulfate dihydrate in 0.1 mol Lꢁ1 H2SO4 as
0.577 [21]). Infrared spectra were measured on a Horiba FT-300
spectrometer. Microanalyses were performed at Research and
Analytical Center for Giant Molecules, Graduate School of Science,
Tohoku University. Sumitomo basic alumina (KCG-30) was used for
second-row
p-conjugated systems such as formation of the very
polar excited state.
4. Experimental
4.1. General
The 1H, 13C, and 31P NMR spectra were measured on a Bruker
AV400 spectrometer. 1H and 13C NMR chemical shifts are expressed
Fig. 4. Cyclic voltammogram of 6 in dichloromethane with 0.1 mol Lꢁ1 n-Bu4NClO4.
Fig. 6. UVeVis and fluorescence spectra of the triarylphosphines 5 and 8 in n-hexane.
Conditions: See Table 1.
Conditions: See Table 1.

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S. Sasaki et al. / Journal of Organometallic Chemistry 696 (2011) 3307e3315
3: orange crystals; mp 144.0e145.5 ꢀC; 1H NMR (400 MHz,
CDCl3, 296 K)
d
9.93 (1H, s, CHO), 7.54 (2H, d, J ¼ 2.80 Hz, arom.(Ar)),
6.91 (4H, d, J ¼ 3.20 Hz, arom.(Tip)), 3.52e3.32 (6H, m, o-CH), 2.83
(2H, sept, J ¼ 6.80 Hz, p-CH), 1.20 (12H, d, J ¼ 6.80 Hz, p-CH3), 1.17
(6H, d, J ¼ 6.80 Hz, o-CH3), 1.14 (6H, d, J ¼ 6.80 Hz, o-CH3), 1.136 (6H,
d, J ¼ 6.80 Hz, o-CH3), 0.73 (6H, d, J ¼ 6.80 Hz, o-CH3), 0.68 (6H, d,
J ¼ 6.80 Hz, o-CH3), 0.64 (6H, d, J ¼ 6.80 Hz, o-CH3); 13C NMR
(101 MHz, CDCl3, 296 K)
d
192.76 (s, CHO), 153.95 (d, JPC ¼ 18.3 Hz,
o-arom.(Ar)), 153.22 (d, JPC ¼ 18.7 Hz, o-arom.(Tip)), 153.16 (d,
JPC ¼ 17.9 Hz, o-arom.(Tip)), 150.00 (s, p-arom.(Tip)), 145.29 (d,
JPC ¼ 32.2 Hz, ipso-arom.(Ar)), 136.15 (s, p-arom.(Ar)), 130.67 (d,
JPC ¼ 21.0 Hz, ipso-arom.(Tip)), 125.05 (d, JPC ¼ 3.8 Hz, m-arom.(Ar)),
122.33 (d, JPC ¼ 5.1 Hz, m-arom.(Tip)), 122.28 (d, JPC ¼ 4.5 Hz,
m-arom.(Tip)), 34.10 (s, p-CH), 32.31 (d, JPC ¼ 18.1 Hz, o-CH), 32.24
(d, JPC ¼ 18.2 Hz, o-CH), 31.96 (d, JPC ¼ 16.0 Hz, o-CH), 24.53 (s, o-
CH3), 23.87 (s, p-CH3), 23.18 (s, o-CH3), 23.02 (s, o-CH3), 22.52 (s, o-
Chart 2. Related p-quinomethanes.
the column chromatography. Recycling preparative HPLC system
Japan Analytical Industry LC-908 with JAIGEL 1Hþ2H column was
used for gel permeation chromatography (GPC). All reactions were
carried out under argon unless otherwise specified. Anhydrous
tetrahydrofuran (Kanto Chemical Co., Inc.) was used for reactions.
Cyclic voltammetry was performed on a BAS CV-50W controller
with a glassy carbon, Pt wire, and Ag/0.01 mol Lꢁ1 AgNO3/
0.1 mol Lꢁ1 n-Bu4NClO4/CH3CN as a working, counter, and reference
CH3); 31P NMR (162 MHz, CDCl3, 296 K)
d
ꢁ48.5 (s); UVeVis
(CH2Cl2, c ¼ 1.68 ꢂ 10ꢁ5 mol Lꢁ1
) lmax (ε)/nm 318 (8600), 407
(7800); (n-hexane, c ¼ 6.73 ꢂ 10ꢁ5 mol Lꢁ1
) lmax (ε)/nm 318 (7900),
388 (7900); IR (KBr) 3043, 2956, 2931, 2867, 2723, 1697 (nC¼O),
1676, 1592, 1556, 1461, 1419, 1361, 1309, 1253, 1242, 1173, 1126, 1101,
1066, 962, 933, 879, 715, 650, 586, 525 and 455 cmꢁ1; FT-ICR-MS
(ESI) Calcd. for [C43H63OP þ H]þ: 627.4689, Found: 627.4693;
Anal. Calcd for C43H63OP: C, 82.38; H, 10.13; Found: C, 82.07; H,
10.18.
electrode, respectively (ferrocene/ferrocenium
¼
0.17 V in
dichloromethane, 0.15 V in tetrahydrofuran). A substrate (ca.
10ꢁ3 mol Lꢁ1) was dissolved in dichloromethane or tetrahydrofuran
with 0.1 mol Lꢁ1 n-Bu4NClO4 as a supporting electrolyte and the
solution was degassed by bubbling with nitrogen gas.
4.2.2. (4-Benzoyl-2,6-diisopropylphenyl)bis(2,4,6-triisopropylphenyl)
phosphine (4)
4.2. Synthesis
To
a solution of (4-bromo-2,6-diisopropylphenyl)bis(2,4,6-
triisopropylphenyl)phosphine (7) (166 mg, 0.245 mmol) in
tetrahydrofuran (2 mL) was added butyllithium (1.56 mol Lꢁ1 in
n-hexane, 0.24 mL, 0.374 mmol) at ꢁ78 ꢀC. The solution was stirred
for 30 min, and then benzonitrile (0.05 mL, 0.49 mmol) was added.
The resultant mixture was stirred for 30 min, gradually warmed to
room temperature, stirred for 3.5 h, then hydrochloric acid solution
(1.2 mol Lꢁ1, 1 mL) was added, and the mixture was stirred for 18 h.
The organic layer was extracted with ether, washed with saturated
sodium hydrogen carbonate solution, saturated sodium chloride
solution, and dried over anhydrous magnesium sulfate. The solu-
tion was filtered and concentrated under reduced pressure. The
residue was purified by column chromatography (Al2O3/n-hexane,
n-hexane/ethyl acetate ¼ 9/1) to give 4 (110 mg, 0.156 mmol, 64%).
4: orange crystals; mp 149.5e151.0 ꢀC; 1H NMR (400 MHz,
4.2.1. (4-Formyl-2,6-diisopropylphenyl)bis(2,4,6-triisopropylphenyl)
phosphine (3)
To
a solution of (4-bromo-2,6-diisopropylphenyl)bis(2,4,6-
triisopropylphenyl)phosphine (7) (380 mg, 0.561 mmol) in tetra-
hydrofuran (5 mL) was added butyllithium (1.58 mol Lꢁ1 in n-
hexane, 0.55 mL, 0.87 mmol) at ꢁ78 ꢀC. The solution was stirred for
30 min, and then N,N-dimethyl formamide (0.09 mL, 1.14 mmol)
was added. The resultant mixture was stirred for 10 min, gradually
warmed to room temperature, stirred for 16 h, cooled to 0 ꢀC, and
then saturated ammonium chloride solution was added. The
organic layer was extracted with ether, washed with saturated
sodium chloride solution, and dried over anhydrous magnesium
sulfate. The solution was filtered and concentrated under reduced
pressure. The residue was purified by column chromatography
(Al2O3/n-hexane, n-hexane/ethyl acetate ¼ 9/1) to give 3 (260 mg,
0.415 mmol, 74%).
CDCl3, 296 K)
d
7.75 (2H, d, J ¼ 7.40 Hz, o-arom.(Ph)), 7.56 (1H, t,
J ¼ 7.40 Hz, p-arom.(Ph)), 7.48 (2H, d, J ¼ 3.20 Hz, arom.(Ar)), 7.46
Scheme 4. Formation of the polar excited state.

S. Sasaki et al. / Journal of Organometallic Chemistry 696 (2011) 3307e3315
3313
(2H, t, J ¼ 7.40 Hz, m-arom.(Ph)), 6.93 (4H, d, J ¼ 2.40 Hz,
arom. (Tip)), 3.57e3.41 (6H, m, o-CH), 2.84 (2H, sept, J ¼ 6.80 Hz, p-
CH), 1.21 (12H, d, J ¼ 6.80 Hz, p-CH3), 1.17 (6H, d, J ¼ 6.80 Hz, o-CH3),
1.15 (6H, d, J ¼ 7.20 Hz, o-CH3), 1.15 (6H, d, J ¼ 7.20 Hz, o-CH3), 0.75
(6H, d, J ¼ 6.80 Hz, o-CH3), 0.70 (6H, d, J ¼ 6.40 Hz, o-CH3), 0.67 (6H,
23.92 (s, p-CH3), 23.13 (s, o-CH3), 23.08 (s, o-CH3), 22.75 (s, o-CH3),
22.68 (s, o-CH3); 31P NMR (162 MHz, CDCl3, 296 K)
ꢁ51.5 (s), ꢁ51.7
d
(s); IR (KBr) 3647, 2964, 2956, 2933, 2868, 1601, 1550, 1462, 1437,
1419, 1382, 1362, 1313, 1259, 1236, 1161, 1099, 1032, 933, 889, 877,
806, 702, 686, 673, 650, 525 and 494 cmꢁ1; UVeVis (CH2Cl2,
c ¼ 3.00 ꢂ 10ꢁ5 mol Lꢁ1) : lmax (ε)/nm 329 (14400); (n-hexane,
c ¼ 1.79 ꢂ 10ꢁ5 mol Lꢁ1) : lmax (ε)/nm 329 (13200); FT-ICR-MS (ESI)
Calcd. for [C63H89O2P þ H]þ: 909.6673, Found: 909.6676.
d, J ¼ 6.40 Hz, o-CH3); 13C NMR (101 MHz, CDCl3, 296 K)
d 197.04
(s, COPh), 153.20 (d, JPC ¼ 18.4 Hz, o-arom.(Ar)), 153.14 (d,
JPC ¼ 18.1 Hz, o-arom.(Tip)), 153.11 (d, JPC ¼ 17.8 Hz, o-arom.(Tip)),
149.84 (s, p-arom.(Tip)), 142.36 (d, JPC ¼ 30.3 Hz, ipso-arom.(Ar)),
138.15 (s, ipso-arom.(Ph)), 136.98 (s, p-arom.(Ar)), 132.16 (s,
p-arom.(Ph)), 130.97 (d, JPC ¼ 21.5 Hz, ipso-arom.(Tip)), 130.06 (s,
o-arom.(Ph)), 128.13 (s, m-arom.(Ph)), 125.68 (d, JPC ¼ 3.8 Hz,
m-arom.(Ar)), 122.25 (d, JPC ¼ 5.2 Hz, m-arom.(Tip)), 122.20 (d,
JPC ¼ 5.0 Hz, m-arom.(Tip)), 34.10 (s, p-CH), 32.27 (d, JPC ¼ 18.0 Hz,
o-CH), 32.19 (d, JPC ¼ 20.0 Hz, o-CH), 32.01 (d, JPC ¼ 16.8 Hz, o-CH),
24.57 (s, o-CH3), 24.51 (s, o-CH3), 24.47 (s, o-CH3), 23.89 (s, p-CH3),
23.21 (s, o-CH3), 23.07 (s, o-CH3), 22.56 (s, o-CH3); 31P NMR
4.2.4. 4-[[4-{Bis(2,4,6-triisopropylphenyl)phosphino}-3,5-diisopro-
pylphenyl](phenyl)methylene]- 2,6-di-tert-butyl-2,5-cyclohexadiene-
1-one (5)
To a solution of 8 (360 mg, 0.396 mmol) in dehydrated benzene
(5 mL) was added one drop of trifluoroacetic acid and the solution
was stirred for 5 min. To a resultant yellow solution was added
triethylamine (0.2 mL) and the mixture was stirred for 5 min. The
reddish purple mixture was poured onto ice-water, extracted with
ether, washed with saturated ammonium chloride solution, satu-
rated sodium chloride solution, and dried over anhydrous magne-
sium sulfate. The solution was filtered and concentrated under
reduced pressure. The residue was purified by column chroma-
tography (Al2O3/n-hexane, n-hexane/ethyl acetate ¼ 24/1) to give 5
(160 mg, 0.180 mmol, 45%).
(162 MHz, CDCl3, 296 K)
d
ꢁ49.5 (s); UVeVis (CH2Cl2,
c ¼ 3.00 ꢂ 10ꢁ5 mol Lꢁ1) : lmax (ε)/nm 318 (8700), 401 (7200); (n-
hexane, c ¼ 1.46 ꢂ 10ꢁ4 mol Lꢁ1) : lmax (ε)/nm 319 (8400), 384
(8100); IR (KBr) 2960, 2931, 2906, 2867, 1658 (nC¼O), 1599, 1593,
1545, 1462, 1383, 1362, 1331, 1274, 1223, 1178, 1163, 1103, 1068, 989,
935, 879, 808, 729, 698, 667, 650, 525 and 492 cmꢁ1; FT-ICR-MS (ESI)
Calcd. for [C49H67OP þ H]þ: 703.5002, Found: 703.5004; Anal. Calcd
for C49H67OP: C, 83.71; H, 9.61; Found: C, 83.78; H, 9.61.
5: brown red solid; mp 117.0e118.5 ꢀC; 1H NMR (400 MHz,
CDCl3, 296 K)
d 7.42e7.33 (3H, m, m,p-arom.(Ph)), 7.22 (1H, d,
J ¼ 2.40 Hz, C]CH), 7.19 (1H, d, J ¼ 2.40 Hz, C]CH), 7.17 (2H, dd,
J ¼ 7.60, 1.80 Hz o-arom.(Ph)), 6.92 (4H, d, J ¼ 3.20 Hz, arom.(Tip)),
6.87 (2H, d, J ¼ 2.80 Hz, arom.(Ar)), 3.60e3.39 (6H, m, o-CH), 2.83
(2H, m, p-CH), 1.24 (9H, s, C(CH3)3), 1.23 (9H, s, C(CH3)3), 1.21 (12H,
d, J ¼ 6.80 Hz, p-CH3), 1.16 (6H, d, J ¼ 6.80 Hz, o-CH3), 1.15 (6H, d,
J ¼ 6.80 Hz, o-CH3), 1.09 (6H, d, J ¼ 6.80 Hz, o-CH3), 0.76 (6H,
d, J ¼ 6.80 Hz, o-CH3), 0.71 (6H, d, J ¼ 6.80 Hz, o-CH3), 0.60 (6H, d,
4.2.3. [4-{Bis(2,4,6-triisopropylphenyl)phosphino}-3,5-diisopropyl-
phenyl](3,5-di-tert-butyl-4-hydroxyphenyl)phenylmethanol (8)
To
a solution of 2,6-di-tert-butyl-4-iodophenol (502 mg,
1.51 mmol) in ether (12 mL) was added butyllithium (1.58 mol Lꢁ1
in n-hexane, 1.92 mL, 3.03 mmol) at ꢁ78 ꢀC. The solution was
warmed to 20 ꢀC, cooled to ꢁ78 ꢀC, and then a solution of the
phosphine 4 (355 mg, 0.504 mmol) in ether (3 mL) was added. The
resultant mixture was gradually warmed to room temperature,
then saturated ammonium chloride solution (5 mL) was added. The
mixture was stirred for 10 min, poured onto ice-water, extracted
with ether, washed with saturated sodium chloride solution, and
dried over anhydrous magnesium sulfate. The solution was filtered
and concentrated under reduced pressure. The residue was purified
by column chromatography (Al2O3/n-hexane, n-hexane/ethyl
acetate ¼ 24/1, 5/1) to give 8 (360 mg, 0.396 mmol, 79%).
J ¼ 6.80 Hz, o-CH3); 13C NMR (101 MHz, CDCl3, 296 K)
d 186.22
(s, CO), 157.31 (s, PhC ¼ ), 153.14 (d, JPC ¼ 18.8 Hz, o-arom.), 152.80
(d, JPC ¼ 17.6 Hz, o-arom.), 152.76 (d, JPC ¼ 17.8 Hz, o-arom.), 149.65
(s, p-arom.(Tip)), 147.12 (s, C-t-Bu), 147.03 (s, C-t-Bu), 140.89 (d,
JPC ¼ 27.4 Hz, ipso-arom.(Ar)),138.46 (s, p-arom.(Ar) or i-arom.(Ph)),
138.19 (s, p-arom.(Ar) or i-arom.(Ph)), 132.52 (s, p-arom.(Ph)),
132.30 (s, o-arom.(Ph)), 132.10 (s, PhC ¼ C), 131.08 (d, JPC ¼ 22.5 Hz,
ipso-arom.(Tip)), 129.24 (s, ¼ CH), 129.22 (s, ¼ CH), 128.21 (d,
JPC ¼ 4.0 Hz, m-arom.(Ar)), 127.71 (s, m-arom.(Ph)), 122.12 (d,
JPC ¼ 4.7 Hz, m-arom.(Tip)), 35.25 (s, C(CH3)3), 35.23 (s, C(CH3)3),
34.08 (s, p-CH), 32.12 (d, JPC ¼ 17.7 Hz, o-CH), 32.08 (d, JPC ¼ 18.1 Hz,
o-CH), 32.01 (d, JPC ¼ 17.0 Hz, o-CH), 29.52 (s, C(CH3)3), 24.60 (s,
o-CH3), 24.52 (s, o-CH3), 24.41 (s, o-CH3), 23.91 (s, p-CH3), 23.15 (s,
o-CH3), 23.05 (s, o-CH3), 22.52 (s, o-CH3); 31P NMR (162 MHz, CDCl3,
8: orange crystals; mp 66.0e68.0 ꢀC; 1H NMR (400 MHz, CDCl3,
296 K)
d
7.25e7.13 (5H, m, arom.(Ph)), 7.02 (2H, d, J ¼ 2.00 Hz,
arom.(Ar)), 6.91 (1H, d, J ¼ 3.60 Hz, arom.(phenol)), 6.90 (1H, d,
J ¼ 3.60 Hz, arom.(phenol)), 6.88 (4H, d, J ¼ 3.20 Hz, arom.(Tip)),
5.171 (0.5H, s, ArOH, dl or meso), 5.165 (0.5H, s, ArOH, dl or meso),
3.55e3.37 (6H, m, o-CH), 2.81 (2H, sept, J ¼ 6.90 Hz, p-CH),
2.65 (1H, s, OH), 1.33 (9H, s, t-Bu), 1.32 (9H, s, t-Bu), 1.19 (12H,
d, J ¼ 6.80 Hz, p-CH3), 1.13 (6H, d, J ¼ 6.80 Hz, o-CH3), 1.12 (6H,
d, J ¼ 6.40 Hz, o-CH3), 1.02 (6H, d, J ¼ 6.00 Hz, o-CH3), 0.68 (6H, d,
J ¼ 5.60 Hz, o-CH3), 0.67 (6H, d, J ¼ 6.00 Hz, o-CH3), 0.54 (6H,
296 K)
d
ꢁ50.6 (s); UVeVis (CH2Cl2, c ¼ 3.00 ꢂ 10ꢁ5 mol Lꢁ1): lmax
(ε)/nm 320sh (18000), 375 (24800), 447sh (13100); (n-hexane,
c ¼ 1.53 ꢂ 10ꢁ5 mol Lꢁ1): lmax (ε)/nm 361 (22600), 433 (12200); IR
(KBr) 2960, 2933, 2970, 1610 (nC¼O), 1462, 1384, 1362, 1257, 1099,
1032, 1024, 962, 933, 918, 893, 877, 768, 700, 525 and 496 cmꢁ1; FT-
ICR-MS (ESI) Calcd. for [C63H87OP
891.6566; Anal. Calcd for C63H87OP: C, 84.89; H, 9.84; Found: C,
84.73; H, 9.82.
d, J ¼ 5.20 Hz, o-CH3); 13C NMR (101 MHz, CDCl3, 296 K)
d
153.04
þ
H]þ: 891.6567, Found:
(d, JPC ¼ 18.1 Hz, o-arom.), 152.87 (d, JPC ¼ 16.0 Hz, o-arom.), 152.44
(d, JPC ¼ 18.2 Hz, o-arom.), 152.40 (d, JPC ¼ 18.2 Hz, o-arom.), 149.24
(s, p-arom.(Tip)), 147.53 (s, CeOH.(phenol)), 147.50 (s, ipso-
arom.(Ph)), 137.51 (s, p-arom.(Ar)), 137.45 (s, p-arom.(Ar)), 134.91
(s, CC(CH3)3), 134.11 (d, JPC ¼ 22.3 Hz, ipso-arom.(Ar)), 131.76 (d,
JPC ¼ 23.6 Hz, ipso-arom.(Tip)), 127.82 (s, m-arom.(Ph)), 127.80 (s,
m-arom.(Ph)), 127.46 (s, o-arom.(Ph)), 126.70 (s, p-arom.(Ph)),
125.17 (s, arom.(phenol)), 123.86 (d, JPC ¼ 4.5 Hz, m-arom.(Ar)),
123.81 (d, JPC ¼ 5.0 Hz, m-arom.(Ar)), 121.95 (d, JPC ¼ 4.1 Hz, m-
arom.(Tip)), 82.54 (s, CPh), 82.52 (s, CPh), 34.39 (s, C(CH3)3), 34.07
(s, p-CH), 32.03 (d, JPC ¼ 17.0 Hz, o-CH), 31.99 (d, JPC ¼ 17.8 Hz, o-CH),
31.94 (d, JPC ¼ 18.1 Hz, o-CH), 31.90 (d, JPC ¼ 17.9 Hz, o-CH), 30.28
(s, C(CH3)3), 24.57 (s, o-CH3), 24.48 (s, o-CH3), 24.42 (s, o-CH3),
4.2.5. 1,2-Bis[4-{bis(2,4,6-triisopropylphenyl)phosphino}-3,5-diiso-
propylphenyl]ethene (6)
To a suspension of titanium (III) chloride (150 mg, 0.973 mmol)
in tetrahydrofuran (9 mL) was added lithium aluminum hydride
(18.9 mg, 0.498 mmol) at 0 ꢀC and the resultant mixture was
refluxed for 15 min. A solution of (4-formyl-2,6-diisopropylphenyl)
bis(2,4,6-triisopropylphenyl)phosphine (3) (230 mg, 0.367 mmol)
in tetrahydrofuran (3 mL) was added at 0 ꢀC and the mixture was
refluxed for 5 h. Water (20 mL) was added at 0 ꢀC and the mixture
was stirred for 5 min, poured onto ice-water, extracted with ether,

3314
S. Sasaki et al. / Journal of Organometallic Chemistry 696 (2011) 3307e3315
washed with saturated sodium hydrogen carbonate solution,
saturated sodium chloride solution, and dried over anhydrous
magnesium sulfate. The solution was filtered and concentrated
under reduced pressure. The residue was purified by column
chromatography (Al2O3/n-hexane) and GPC (Jaigel 1Hþ2H, toluene)
to give 6 (30.0 mg, 0.0246 mmol, 13%) as an E/Z mixture (1/0.3).
6: yellow solid; mp 274.0e276.0 ꢀC; (E)-6:1H NMR (400 MHz,
F(000) ¼ 3072.00. Of 44046 reflections measured (2qmax ¼ 51.0ꢀ),
7422 were observed [I > 0.0
s
(I)] (Rint ¼ 0.051). Variable parameters
920. Goodness of fit S ¼ 1.96 for observed reflections, and R1 ¼0.067
for I > 2.0
s
(I), R ¼ 0.077 Rw ¼ 0.086 for all reflections. The maximum
and minimum peaks on the final difference Fourier map corre-
sponded to 0.42 and ꢁ0.45 eÅꢁ3, respectively. CCDC 801474.
CDCl3, 296 K)
d
7.23 (4H, d, J ¼ 3.20 Hz, arom.(Ar)), 7.09 (2H, s, CH]
Acknowledgement
CH), 6.89 (8H, d, J ¼ 3.20 Hz, arom.(Tip)), 3.58e3.38 (12H, m, o-CH),
2.82 (4H, sept, J ¼ 6.90 Hz, p-CH), 1.20 (24H, d, J ¼ 6.80 Hz, p-CH3),
1.19 (12H, d, J ¼ 6.80 Hz, o-CH3), 1.14 (24H, d, J ¼ 6.40 Hz, o-CH3),
0.72 (12H, d, J ¼ 6.80 Hz, o-CH3), 0.70 (12H, d, J ¼ 6.80 Hz, o-CH3),
0.66 (12H, d, J ¼ 6.40 Hz, o-CH3); 13C NMR (101 MHz, CDCl3, 296 K)
We thank Grants-in-Aid for Scientific Research from the
Ministry of Education, Culture, Sports, Science and Technology,
Japan (Nos. 17310063, 22605001) for financial support, Research
and Analytical Center for Giant Molecules, Graduate School of
Science, Tohoku University, for taking mass spectra and elemental
analysis.
d
153.37 (d, JPC ¼ 18.4 Hz, o-arom.), 153.04 (d, JPC ¼ 18.2 Hz,
o-arom.), 153.03 (d, JPC ¼ 17.6 Hz, o-arom.), 149.31 (s, p-arom.(Tip)),
137.20 (s, p-arom.(Ar)), 135.52 (d, JPC ¼ 26.1 Hz, ipso-arom.(Ar)),
131.77 (d, JPC ¼ 22.8 Hz, ipso-arom.(Tip)), 128.27 (s, CH]CH), 122.23
(d, JPC ¼ 4.2 Hz, m-arom. (Ar)), 122.00 (d, JPC ¼ 4.2 Hz, m-arom.
(Tip)), 34.08 (s, p-CH), 32.04 (d, JPC ¼ 18.2 Hz, o-CH), 32.02 (d,
JPC ¼ 18.3 Hz, o-CH), 31.95 (d, JPC ¼ 17.0 Hz, o-CH), 24.60 (s, o-CH3),
24.56 (s, o-CH3), 24.54 (s, o-CH3), 23.93 (s, p-CH3), 23.26 (s, o-CH3),
23.03 (s, o-CH3), 22.87 (s, o-CH3); 31P NMR (162 MHz, CDCl3, 296 K)
Appendix. Supplementary material
CCDC 801473 and 801474 contain the supplementary crystallo-
graphic data for 3 and 4. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via www.ccdc.
cam.ac.uk/data_request/cif.
d
ꢁ50.9 (s); (Z)-6:1H NMR (400 MHz, CDCl3, 296 K)
d7.03 (2H, d,
J ¼ 3.60 Hz, arom.(Ar, dl or meso)), 7.02 (2H, d, J ¼ 4.00 Hz, arom.(Ar,
dl or meso)), 6.88 (8H, d, J ¼ 2.40 Hz, arom.(Tip, dl or meso)), 6.87
(8H, d, J ¼ 2.80 Hz, arom.(Tip, dl or meso)), 6.46 (2H, s, CH]CH, dl
or meso), 6.45 (2H, s, CH]CH, dl or meso), 3.58e3.38 (12H þ 12H,
m, o-CH), 2.82 (4H þ 4H, sept, J ¼ 6.90 Hz, p-CH),1.19 (24H þ 24H, d,
J ¼ 6.60 Hz, p-CH3), 1.15e1.04 (36H þ 36H, o-CH3), 0.62 (12H þ 12H,
d, J ¼ 6.53 Hz, o-CH3), 0.61 (12H þ 12H, d, J ¼ 6.75 Hz, o-CH3), 0.59
(12H þ 12H, d, J ¼ 6.88 Hz, o-CH3); 31P NMR (162 MHz, CDCl3,
Appendix. Supplementary material
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.jorganchem.2011.07.013.
References
[1] (a) S. Sasaki, K. Sutoh, F. Murakami, M. Yoshifuji, J. Am. Chem. Soc. 124 (2002)
14830;
296 K)
d
ꢁ50.7 (s, dl or meso), ꢁ50.9 (s, dl or meso); UVeVis (CH2Cl2,
c ¼ 5.10 ꢂ 10ꢁ6 mol Lꢁ1): lmax (ε)/nm 309 (27000), 391 (23000);
(n-hexane, c ¼ 7.82 ꢂ 10ꢁ6 mol Lꢁ1): lmax (ε)/nm 312 (20700), 380
(16200); IR (KBr) 3045, 2964, 2929, 2868, 1599, 1549, 1462,
1417, 1383, 1362, 1308, 1261, 1238, 1186, 1161, 1126, 1101, 1063,
958, 935, 879, 804 and 652 cmꢁ1; FT-ICR-MS (ESI) Calcd. for
[C86H126P2 þ H]þ: 1221.9408, Found: 1221.9414; Anal. Calcd for
C86H126P2ꢃCHCl3: C, 77.91; H, 9.54; Found: C, 77.68; H, 9.94.
(b) R.T. Boeré, Y. Zhang, J. Organomet. Chem. 690 (2005) 2651;
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(d) K. Sutoh, S. Sasaki, M. Yoshifuji, Inorg. Chem. 45 (2006) 992;
(e) S. Sasaki, K. Sasaki, M. Yoshifuji, Phosphorus, Sulfur Silicon Relat. Elem. 183
(2008) 410.
4.3. X-ray crystallography
[4] (a) S. Sasaki, F. Murakami, M. Murakami, M. Watanabe, K. Kato, K. Sutoh,
M. Yoshifuji, J. Organomet. Chem. 690 (2005) 2664;
(b) S. Sasaki, K. Ogawa, M. Watanabe, M. Yoshifuji, Organometallics 29 (2010)
757.
[5] S. Sasaki, K. Kato, M. Yoshifuji, Bull. Chem. Soc. Jpn. 80 (2007) 1791.
[6] A. Mishra, R.K. Behera, P.K. Behera, B.K. Mishra, G.B. Behera, Chem. Rev. 100
(2000) 1973.
The single crystal data were collected using a Rigaku RAXIS-IV
imaging plate area detector with graphite monochromated Mo-Ka
radiation (
l
¼ 0.71069 Å). The structure was solved by direct
methods (SIR92) [22], expanded using Fourier techniques (DIR-
DIF94) [23], and refined by full matrix least squares on F. The non-
hydrogen atoms were anisotropically refined. The hydrogen atoms
were included but not refined. The structure solution, refinement,
and graphical representation were carried out using the teXsan
package [24].
[7] (a) R.A. Rijkenberg, D. Bebelaar, W.J. Buma, J.W. Hofstraat, J. Phys. Chem. A 106
(2002) 2446;
(b) M. Cha, W.E. Torruellas, G.I. Stegeman, W.H.G. Horsthius, G. Möhlmann,
R.J. Meth, Appl. Phys. Lett. 65 (1994) 2648;
(c) D. Beljonne, J.L. Bredas, M. Cha, W.E. Torruellas, G.I. Stegeman,
J.W. Hofstraat, W.H.G. Horsthius, G.R. Möhlmann, J. Chem. Phys. 103 (1995)
7834.
Crystal data of 3: C43H63OP, M ¼ 626.94, orange block, crystal
[8] (a) H. Suzuki, S. Hoshino, J. Appl. Phys. 79 (1996) 8816;
(b) B.-J. Jung, C.-B. Yoon, H.-K. Shim, L.-M. Do, T. Zyung, Adv.Funct. Mater. 11
(2001) 430.
dimensions 0.50 ꢂ 0.50 ꢂ 0.30 mm3, monoclinic, space group P21/c
(no.14), a ¼ 10.361(1), b ¼ 36.114(2), c ¼ 10.662(1) Å,
b
¼ 100.211(2)ꢀ,
[9] H. Christensen, Synth. Commun. 5 (1975) 65.
V ¼ 3926.3(6) Å3, Dc ¼ 1.061 gcmꢁ3
,
m
¼ 0.099 mmꢁ1, T ¼ 140 K, Z ¼ 4,
[10] V. Ramanathan, R. Levine, J. Org. Chem. 27 (1962) 1216.
[11] H. Kurata, T. Tanaka, T. Sauchi, T. Kawase, M. Oda, Chem. Lett. (1997) 947.
[12] K. Ley, E. Müller, R. Mayer, K. Scheffler, Chem. Ber. 91 (1958) 2670.
[13] C. Betschart, D. Seebach, Chimia 43 (1989) 39.
[14] (a) P. Changenet, P. Plaza, M.M. Martin, Y.H. Meyer, W. Rettig, Chem. Phys. 221
(1997) 311;
F(000) ¼ 1376.00. Of 29150 reflections measured (2qmax ¼ 51.0ꢀ),
7166 were observed [I > 0.0
407. Goodness of fit S ¼ 3.69 for observed reflections, and R1 ¼0.082
s
(I)] (Rint ¼ 0.048). Variable parameters
for I > 2.0
s
(I), R ¼ 0.092 Rw ¼ 0.160 for all reflections. The maximum
(b) Y. Sakaguchi, H. Hayashi, J. Phys. Chem. A 108 (2004) 3421.
[15] (a) A. Hubele, H. Suhr, U. Heilmann, Chem. Ber. 95 (1962) 639;
(b) H.-D. Becker, J. Org. Chem. 32 (1967) 2115;
and minimum peaks on the final difference Fourier map corre-
sponded to 0.92 and ꢁ0.62 eÅꢁ3, respectively. CCDC 801473.
Crystal data of 4: C49H67OP, M ¼ 703.74, orange block, crystal
dimensions 0.50 ꢂ 0.50 ꢂ 0.50 mm3, orthorhombic, space group
Pca21 (no. 29), a ¼ 24.2449(6), b ¼ 10.7761(4), c ¼ 34.899(1) Å,
ꢀ
(c) L. Musil, B. Koutek, J. Velek, M. Soucek, Coll. Czech. Chem. Commun. 49
(1984) 1949.
[16] (a) R. Suzuki, H. Kurata, T. Kawase, M. Oda, Chem. Lett. (1999) 571;
(b) T. Kawase, N. Nishigaki, H. Kurata, M. Oda, Eur. J. Org. Chem. (2004)
3090.
V ¼ 9117(1) Å3, Dc ¼ 1.02 gcmꢁ3
,
m
¼ 0.092 mmꢁ1, T ¼ 140 K, Z ¼ 8,

S. Sasaki et al. / Journal of Organometallic Chemistry 696 (2011) 3307e3315
3315
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