PhP-PPh group bound to 1,8-positions of naphthalene: Preparation of cis isomer and synthesis of binuclear complex

Article abstract of DOI:10.1016/j.jorganchem.2011.07.030

A thermodynamically less stable cis isomer of 1,2-diphosphacycle was prepared from the corresponding trans isomer. Diphosphine, in which a PhP-PPh bond bridges the 1,8-positions of naphthalene, 1,2-diphenyl-1,2- dihydronaphtho[1,8-cd][1,2]diphosphole (1), was first prepared according to a previously reported method, and the trans isomer of 1 was irradiated in tetrahydrofuran with UV-vis light to reach equilibrium with cis-1 in a trans:cis ratio of 1:2. When a similar photochemical conversion was carried out using a saturated hexane solution of trans-1, cis-1 was precipitated in a good yield of 94%. The configuration of cis-1 was confirmed by X-ray analysis. Both cis- and trans-1 diphosphine ligands were used for the preparation of binuclear gold complexes. The crystal structure of (μ-cis-1)-[AuCl]₂ demonstrated that the two lone pairs of cis-1 are suitably directed for arrangement of the two gold centers in close proximity to each other. The two independent (μ-cis-1)-[AuCl]₂ molecules in the crystal were found to form a dimer through the multiple intermolecular interaction among the gold centers.

Full text of DOI:10.1016/j.jorganchem.2011.07.030

Journal of Organometallic Chemistry 696 (2011) 3402e3407
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
PhPePPh group bound to 1,8-positions of naphthalene: Preparation of cis isomer
and synthesis of binuclear complex
*
Yuichi Teramoto, Kazuyuki Kubo, Tsutomu Mizuta
Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-hiroshima 739-8526, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
A thermodynamically less stable cis isomer of 1,2-diphosphacycle was prepared from the corresponding
trans isomer. Diphosphine, in which a PhPePPh bond bridges the 1,8-positions of naphthalene, 1,2-
diphenyl-1,2-dihydronaphtho[1,8-cd][1,2]diphosphole (1), was first prepared according to a previously
reported method, and the trans isomer of 1 was irradiated in tetrahydrofuran with UVevis light to reach
equilibrium with cis-1 in a trans:cis ratio of 1:2. When a similar photochemical conversion was carried
out using a saturated hexane solution of trans-1, cis-1 was precipitated in a good yield of 94%. The
configuration of cis-1 was confirmed by X-ray analysis. Both cis- and trans-1 diphosphine ligands were
Received 2 June 2011
Received in revised form
20 July 2011
Accepted 22 July 2011
Keywords:
Photochemical isomerization
Diphosphacycle
Trans-to-cis isomerization
Binuclear gold complex
used for the preparation of binuclear gold complexes. The crystal structure of
demonstrated that the two lone pairs of cis-1 are suitably directed for arrangement of the two gold
centers in close proximity to each other. The two independent ( -cis-1)-[AuCl]2 molecules in the crystal
(m-cis-1)-[AuCl]2
m
were found to form a dimer through the multiple intermolecular interaction among the gold centers.
Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction
isomers [2e4]. A relatively limited number of reports have
mentioned the formation of cis isomers [5e15], in which bicyclic ring
systems are incorporated to avoid repulsion between the substitu-
ents on the phosphorus centers [5e14], or a W(CO)5 fragment is
used to reverse the preference for the trans isomer [2,15].
Diphosphines (R2PePR2) are useful bridging ligands for
syntheses of binuclear complexes, two metal centers of which are
coordinated to the respective phosphorus centers of the bridging
diphosphines, and are linked in close proximity bya direct PeP bond
[1,2]. In practice, however, the distance between the two metal
centers varies depending on the torsion angle of the MePePeM
bond sequence, as shown in Fig. 1. In the synperiplanar conforma-
tion shown in Fig. 1a, the two metal centers become closest to each
other, and rotation of an R2PMLn group around the PeP bond makes
the metal centers move away from each other, as shown in Fig. 1b.
However, the rotation of the R2PMLn groups is restricted if a PeP
bond is a part of a diphosphacycle [2,3]. Diphosphacycles have two
configurational isomers, cis and trans, as illustrated in Fig. 1c and d,
respectively. The cis isomer is more useful than the trans isomer,
because two lone pairs on the diphosphine unit adopt a synper-
iplanar disposition.
Our group has reported 1,2-diphenyl-1,2-dihydronaphtho[1,8-
cd][1,2]diphosphole (1), in which a PeP bond is connected to
a naphthalene group to form a fused five membered diphospha-
cycle [2]. The cis isomer of 1 has two Ph groups on the same side
with respect to the naphthalene plane with two phosphorus lone
pairs adopting the synperiplanar disposition, while trans-1 has two
Ph groups disposed on mutually opposite sides of the plane. We
have previously reported that trans-1 could be isolated in
a moderate yield, while cis-1 was difficult to isolate due to low yield
However, of the two 1,2-diphosphacycles shown in Fig. 1c and d,
the cis isomer is less stable than the trans isomer due to steric
repulsion between the substituents on the two adjacent phosphorus
centers. Therefore, although many four-, five-, and six-membered
1,2-diphosphacycles have been reported, most of them are trans
* Corresponding author. Tel.: þ81 82 424 7420; fax: þ81 82 424 0729.
E-mail address: mizuta@sci.hiroshima-u.ac.jp (T. Mizuta).
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.07.030

Y. Teramoto et al. / Journal of Organometallic Chemistry 696 (2011) 3402e3407
3403
according to our previously reported method [2]. A 31P{1H} nuclear
magnetic resonance (NMR) spectrum of this mixture showed two
singlets at ꢀ9 and ꢀ19 ppm in an intensity ratio of 10:1, which were
assigned to trans-1 and cis-1, respectively. The minor cis isomer was
separated by chromatography using an Al2O3 column. Although the
total yield of cis-1 was only 1e2%, the molecular structure of cis-1
was confirmed by X-ray analysis, as shown in Fig. 2, in which both
Ph groups on the phosphorus centers are on the same side with
respect to the naphthalene plane. Selected bond distances and
angles of cis-1 are listed in Table 1. The PeP bond length of cis-1 is
2.2710 (7) Å, which is slightly greater than that of trans-1 (2.2240
(6) Å) reported previously [2c]. A greater electrostatic repulsion
between lone pairs of cis-1 in the synperiplanar conformation
might be responsible for the longer PeP bond. In the 1H NMR
spectrum of cis-1, three signals assigned to the naphthalene group
were observed at 7.59, 7.72, and 7.93 ppm, which are close to those
of trans-1 (7.63, 7.84, and 7.97 ppm, respectively) [2]. In contrast,
signals assigned to Ph groups of cis-1 appeared at 6.59, 6.80, and
6.95 ppm, which are at a substantially lower chemical shift than
those of trans-1 at 7.10e7.15 ppm [2]. The two Ph groups in cis-1
adopt a parallel arrangement, as shown in Fig. 2, which is respon-
sible for the shielded protons compared to those of trans-1.
Fig. 1. (a) Synperiplanar and (b) antiperiplanar conformations of
bridged binuclear complex. (c) cis and (d) trans isomers of diphosphacycle.
a diphosphine-
and thermodynamic instability from the steric congestion of the
two Ph groups. The isolated trans-1 isomer was used for the
preparation of a binuclear tungsten complex, (m-trans-1)-[W(CO)5]2
(trans-2). The corresponding cis complex, ( -cis-1)-[W(CO)5]2 (cis-
m
2), which is expected to have a smaller W/W distance, was
synthesized starting from trans-1 in accordance with Scheme 1, in
which a portion of the trans-1 ligands were isomerized to cis-1
through stepwise reactions [2c]. Although this method gave the
binuclear complex with a bridging diphosphacyle in the cis
configuration, synthesis of the free cis ligand is desirable for the
preparation of a variety of binuclear complexes.
In this paper, we report a practical method for the synthesis of
cis-1, in which free trans-1 is converted to cis-1 by irradiation with
UVevis light. Photochemical trans-to-cis conversion is well known
for unsaturated compounds having C]C and N]N bonds [16e19],
while little is known regarding that for the PeP single bond of
a diphosphacycle. The only example is that reported by Regitz et al.
[11]. Although they reported the isomerization of 1,2-dihydro-1,2-
diphosphete (3), cis-3 was not separated from a 1:1 mixture with
trans-3. Here we report the isolation of cis-1, and its properties as
a bridging ligand.
2.2. Photochemical isomerization
The cis isomer of 1 could be directly obtained from a reaction
mixture, although the yield was very low. A more practical method
is desirable for preparation of binuclear complexes using cis-1 as
a bridging group. Therefore, because trans-1 was obtained in
a moderate yield, a trans-to-cis conversion was attempted. Firstly,
the thermal transformation of trans-1 to cis-1 was conducted by
heating a solution of pure trans-1 in toluene. The 31P{1H} NMR
spectrum of the solution showed that only a trace amount (w1%) of
cis-1 was formed, which indicates the much higher thermodynamic
stability of trans-1. The thermodynamic preference was also
confirmed by an almost complete conversion of isolated cis-1 to
trans-1 at 80 ꢁC within 3 h.
On the other hand, irradiation of trans-1 with UVevis light
proved successful. When a solution of trans-1 in tetrahydrofuran
(THF) was irradiated for 1 h with UVevis light using a medium
pressure mercury lamp, a substantial amount of trans-1 was found
to be converted to cis-1 to reach an equilibrium with a trans:cis ratio
of 1:2. In addition, it was found that a similar photochemical
reaction using hexane as the solvent gave cis-1 as a precipitate,
while all of the remaining trans-1 stayed in solution. This is prob-
ably because cis-1 has a larger dipole moment than trans-1, and
2. Results and discussion
2.1. Preparation of cis-1
A crude mixture of trans- and cis-1 was prepared in a moderate
yield by the reaction of 1,8-dilithionaphthalene with PCl2Ph
Fig. 2. Molecular structure of cis-1. Ellipsoids are shown at 50%. Hydrogen atoms are
Scheme 1.
omitted for clarity.

3404
Y. Teramoto et al. / Journal of Organometallic Chemistry 696 (2011) 3402e3407
Table 1
The binuclear gold complexes were prepared by reaction of cis-
or trans-1 with two equivalents of AuCl(tht) (tht ¼ tetrahydroth-
iophene). The reactions proceeded smoothly to give the binuclear
Selected bond lengths and angles for cis-1, (
[AuCl]2 (trans-4).
m-cis-1)-[AuCl]2 (cis-4), and (m-trans-1)-
Cis-1
Cis-4
Trans-4
complexes (m-cis-1 and m-trans-1)-[AuCl]2 (4), cis- and trans-4,
respectively. The 31P{1H} NMR spectra of cis- and trans-4 showed
a sharp singlet at 24.2 and 33.0 ppm, respectively, which are at
lower field by about 40 ppm than those of the corresponding free
ligands. In 1H and 13C{1H} NMR spectra, signals assigned to naph-
thalene groups of cis- and trans-4 indicated spectral patterns
consistent with their Cs and C2 symmetry, respectively.
Molecule 1
Molecule 2a
Selected bond length (Å)
P2
Au1
Au2
P1
P2
P1
P2
Au1
Au2
Selected bond angles (deg)
P1
P2
Au1
Au2
C1
P1
P1
P2
C1
2.2710 (7)
2.2331 (18)
2.2259 (14)
2.2309 (14)
1.818 (5)
1.806 (5)
1.803 (6)
1.812 (6)
2.2869 (13)
2.2938 (13)
2.2294 (18)
2.2254 (15)
2.2275 (13)
1.814 (5)
1.806 (6)
1.822 (6)
1.789 (5)
2.2903 (14)
2.2852 (13)
2.208 (3)
2.209 (2)
2.213 (2)
1.797 (9)
1.808 (9)
1.796 (9)
1.794 (9)
2.274 (2)
2.269 (2)
1.8291 (18)
1.8320 (18)
1.8323 (17)
1.8259 (18)
C8
The X-ray structures of these complexes are presented in Figs. 3
and 4, respectively, in which the AuCl fragment coordinates to each
phosphorus donor atom to form the expected binuclear complexes.
Two independent molecules were found in the crystal of cis-4.
Selected bond distances and angles of the two cis-4 and trans-4
molecules are given in Table 1. A mean AueP bond distance of the
two cis-4 molecules is 2.2274 (14) Å, which is slightly greater than
that of trans-4, 2.211 (2) Å, but both distances are in a range for
a usual AueP bond distance. PeP bond distances of the two cis-4
molecules are 2.2331 (18) and 2.2294 (18) Å, which are significantly
reduced by 0.0379 and 0.0416 Å, respectively, from that of free cis-1
(2.2710 (7) Å). In contrast, for trans-4, a reduction of the PeP bond
distance upon the coordination of free trans-1 to the two Au centers
becomes much smaller. The PeP bond distance of trans-4 (2.208 (3)
Å) is smaller by 0.016 Å than that of free trans-1 (2.2243 (6) Å). The
greater reduction of the PeP bond in cis-4 is mainly due to removal
of the lone pairelone pair repulsion present in free cis-1 which has
longer PeP bond than free trans-1, vide supra.
C11
C17
Cl1
Cl2
Au1
Au2
P1
P2
P1
P2
P1
P2
P1
Cl1
Cl2
P2
P1
P2
P1
P2
P1
C1
C17
174.03 (5)
167.58 (5)
114.04 (7)
115.65 (7)
93.01 (17)
93.83 (17)
109.80 (18)
113.79 (17)
105.7 (2)
175.19 (5)
168.41 (5)
112.95 (7)
115.31 (7)
92.22 (17)
93.25 (17)
106.75 (17)
112.73 (18)
104.0 (3)
176.26 (9)
175.40 (9)
114.94 (12)
111.23 (11)
93.6 (3)
92.99 (6)
93.02 (6)
102.54 (6)
104.12 (6)
104.05 (8)
104.22 (8)
C8
94.5 (3)
C11
C17
C11
C8
105.0 (3)
104.0 (3)
108.8 (4)
105.5 (4)
P2
107.0 (2)
107.4 (3)
a
For atom labels of molecule 2, Au1, Au2, Cl1, Cl2, P1, P2, C1, C8, C11, and C17
should be read as Au3, Au4, Cl3, Cl4, P3, P4, C23, C30, C33, and C39, respectively.
thus its solubility in the non-polar solvent is significantly lower
than that of trans-1. Eventually, as shown in Scheme 2, a practical
amount (94%) of cis-1 was obtained by irradiation of a hexane
solution saturated with trans-1 for 6 h, and more cis-1 could be
obtained if the irradiation was repeated after concentration of the
recovered trans-1 solution.
Mean PeAueCl angles of cis-4 and trans-4 are 171.30 (5)ꢁ and
175.83 (9)ꢁ, respectively, indicating that the former deviates from
a linear structure probably due to the Au$$$Au interaction present
only in the former, vide infra. In cis-4, a pair of the PeAueCl units for
each independent molecule adopts the synperiplanar arrangement
with AuePePeAu torsion angles of 11.6 (1) and 18.3 (1)ꢁ to form
a “U” shape structure. The intramolecular Au/Au distances of two
2.3. Synthesis of metal complexes
In the previous method shown in Scheme 1, a binuclear tung-
sten complex bridged with cis-1 was prepared starting from
[W(trans-1)(CO)5]. Now the same binuclear complex (m-cis-1)-
[W(CO)5]2 (cis-2) can be obtained in a good yield through a direct
reaction of cis-1 with a slight excess of [W(CO)5(thf)]. However, as
reported previously, a shorter W/W distance of 5.1661 (3) Å in cis-
2 than that of 5.8317 (2) Å in the trans analog trans-2 was observed,
but the difference was only 0.6652 (2) Å, which was smaller than
expected [2c]. The reason for the small difference must be steric
congestion between the bulky [W(CO)5] fragments in cis-2.
To remove such steric factor, an AuCl fragment was selected as
a small metal fragment. In addition, gold(I) complexes have
attracting recent interest because of the “aurophilicity” which plays
an important role to form molecular assemblies of gold(I)
complexes in a solid state [20]. The present cis diphosphine ligand,
cis-1, is expected to form a binuclear gold complex with the two
gold centers in close proximity. Therefore, it is of interest whether
the two gold centers form an intramolecular AueAu bond or an
assembly of the binuclear gold complexes by cooperative inter-
molecular AueAu interactions.
Fig. 3. Structures of two independent cis-4 molecules in the crystal. Ellipsoids are
shown at 50%. Hydrogen atoms are omitted for clarity. Broken lines indicate AueAu
interactions, and their distances are 3.1960 (4) Å (Au1eAu3), 3.1934 (4) Å (Au2eAu4),
3.6121(4) Å (Au1eAu4), and 3.4608 (4) Å (Au2eAu3).
Scheme 2.

Y. Teramoto et al. / Journal of Organometallic Chemistry 696 (2011) 3402e3407
3405
using sodium (for hexane and toluene), sodium/benzophenone (for
ether and THF), or P2O5 (for CH2Cl2). The purified solvents were
stored under nitrogen. 1,8-Dilithionaphthalene and AuCl(tht) were
prepared according to methods in the literature [23,24]. Al2O3
(standardized, Merck) and other reagents were used as received.
NMR spectra were recorded on a Jeol LA-300 spectrometer. 1H
and 13C NMR chemical shifts were reported relative to Me4Si and
were determined by reference to the residual solvent peaks. 31P
NMR chemical shifts were reported relative to H3PO4 (85%) used as
an external reference. Elemental analyses were performed with
a PerkineElmer CHNS 2400II elemental analyzer. Photolysis was
carried out using Pyrex-glass-filtered emission from a 400 W
mercury arc lamp (Riko-Kagaku Sangyo UVL-400P). The emission
lines used and their relative intensities (in parenthesis) were: 577.0
(69), 546.1 (82), 435.8 (69), 404.7 (42), 365.0 (100), 334.1 (7), 312.6
(38), and 302.2 (9) nm.
Fig. 4. Molecular structure of trans-4. Ellipsoids are shown at 50%. Hydrogen atoms are
omitted for clarity.
4.2. Synthesis of 1,2-diphenyl-1,2-dihydronaphtho[1,8-cd][1,2]
diphosphole (1) (trans- and cis-1)
cis-4 are 4.1260 (4) Å for Au1/Au2 and 4.1007 (3) Å for Au3/Au4,
indicating absence of the intramolecular Au/Au interaction. These
values are substantially smaller than the corresponding value of
5.2390 (7) Å in trans-4, and are significantly less than the W/W
distance of 5.1661 (3) Å in cis-2, as expected. Reduction of MeP
distances in the gold complexes compared to the tungsten
complexes also contributes to the shorter M/M distances, but
a dominant factor is considered to be the reduction in the steric
bulkiness of the metal fragments in the gold complex [21].
It is noteworthy that the two independent cis-4 molecules in the
crystal form a dimeric assembly, as shown in Fig. 3, where the two
“U” shape parts of the cis-4 molecules are interlocked each other.
One cis-4 molecule interacts with the other through multiple
AueAu interactions represented by broken lines in Fig. 3. The
intermolecular AueAu distances are 3.1960 (4) Å (Au1eAu3),
3.1934 (4) Å (Au2eAu4), 3.6121 (4) Å (Au1eAu4), and 3.4608 (4) Å
(Au2eAu3). The two former distances are in a common range for
typical AueAu interactions [20]. On the other hand, no intermo-
lecular AueAu interaction was found in the crystal structure of
trans-4. The contrasting results suggest that the two Au centers in
close proximity in cis-4 work simultaneously to form the dimer
through the multiple AueAu interactions [22], while such cooper-
ative interaction is not possible for the two remote Au centers in
trans-4, resulting in the discrete molecule in a solid state.
Diphosphine 1 was synthesized by modification of a previously
reported method [2]. A Schlenk tube charged with nBuLi (28 mL,
46 mmol,1.65 mol/L hexane solution) and ether (30 mL) was cooled
to ꢀ30 ꢁC. 1-Bromonaphthalene (5.3 mL, 38 mmol) was slowly
added to the Schlenk tube and the mixture was stirred for 1.5 h.
After the product was settled as a white precipitate, the superna-
tant was removed. The precipitate was washed 4 times with hexane
(50 mL aliquots) at ꢀ20 ꢁC, and then nBuLi (30 mL, 49 mmol,
1.65 mol/L hexane solution) and tetramethylethylenediamine
(8.2 mL, 54 mmol) were added. The mixture was kept at 75 ꢁC until
the evolution of gas ceased (w3 h). During heating, the mixture
became homogeneous, followed by formation of a yellow precipi-
tate. The yellow product was settled and the supernatant was
removed. After the precipitate was washed 4 times with hexane
(50 mL aliquots), hexane (100 mL) was added. The mixture was
cooled to ꢀ30 ꢁC and PhPCl2 (5.7 mL, 42 mmol) was added drop-
wise to the mixture, which was then stirred for 2 h during which
the mixture was warmed to room temperature, ensuring that the
temperature did not rise above 20 ꢁC. The supernatant containing
diphosphine 1 was separated, and 1 was further extracted from the
residue using toluene (50 mL aliquots) 4 times. The supernatant
and extracts were combined, and the solvents were removed under
reduced pressure. The crude product was loaded into an Al2O3
column (30 mm i.d. ꢂ 300 mm). Trans-1 was eluted with CH2Cl2/
hexane ¼ 1/1 and cis-1 followed. Since the latter band overlapped
with the tail of the former, pure cis-1 was obtained from the tail of
the latter band. Removal of solvents in vacuo gave trans-1 (2.51 g,
19%) and cis-1 (0.24 g 1.9%). Although trans-1 was fully character-
ized in the previous report [2], NMR data were given below for
comparison.
3. Conclusions
The thermodynamically less stable cis isomer of a diphospha-
cycle, cis-1, was prepared by a practical method, in which the cor-
responding trans isomer, trans-1, was photochemically converted to
cis-1 in good yield (94%). The two lone pairs of cis-1 are suitably
directed to coordinate the two AuCl fragments in close proximity,
which facilitates the formation of a dimer with their “U” shape
parts interlocked by the multiple intermolecular interaction among
the gold centers.
Data for trans-1. 1H NMR (300.5 MHz, CD2Cl2):
d 7.10e7.20 (m,
10H, Ph), 7.63 (t, JHH ¼ 7.0 Hz, 2H, 3,6-Naph), 7.84 (m, 2H, 2,7-Naph),
7.97 (d, JHH ¼ 8.1 Hz, 2H, 4,5-Naph). 13C{1H} NMR (75.6 MHz,
CD2Cl2):
d
127.8 (t, JPC ¼ 3.7 Hz, 3,6-Naph), 128.5 (s, 4,5-Naph),128.8
(t, JPC ¼ 2.8 Hz, m-Ph), 128.9 (s, p-Ph), 132.4 (t, JPC ¼ 12.4 Hz, o-Ph),
132.6 (t, JPC ¼ 12.4 Hz, 2,7-Naph), 134.1 (s, Naph), 138.9 (t,
JPC ¼ 5.0 Hz, ipso-Ph), 142.1 (t, JPC ¼ 14.0 Hz, ipso-Naph), 142.3 (s,
The reaction mechanism for the photochemical conversion will
be the subject of future research, and syntheses of a variety of
binuclear complexes with cis-1 are currently underway.
Naph). 31P{1H} NMR (121.7 MHz, CD2Cl2):
d
ꢀ8.6 (s).
6.57e6.61 (m, 4H,
Data for cis-1. 1H NMR (300.5 MHz, CD2Cl2):
d
4. Experimental section
o-Ph), 6.80 (t, JHH ¼ 7.5 Hz, 4H, m-Ph), 6.95 (t, JHH ¼ 7.3 Hz, 2H, p-
Ph), 7.59 (t, JHH ¼ 7.5 Hz, 2H, 3,6-Naph), 7.70e7.75 (m, 2H, 2,7-
4.1. General remarks
Naph), 7.93 (d, JHH
(75.6 MHz, CD2Cl2):
JPC ¼ 3.0 Hz, m-Ph), 128.2 (s, 4,5-Naph), 128.3 (s, p-Ph), 131.8 (t,
¼
8.3 Hz, 2H, 4,5-Naph). 13C{1H} NMR
127.7 (t, JPC ¼ 2.3 Hz, 3,6-Naph), 128.1 (t,
d
All reactions were carried out under a dry nitrogen atmosphere
using Schlenk tube techniques. All solvents were distilled and dried
JPC ¼ 11.6 Hz, 2,7-Naph), 133.1 (t, JPC ¼ 10.9 Hz, o-Ph), 134.3 (s,

3406
Y. Teramoto et al. / Journal of Organometallic Chemistry 696 (2011) 3402e3407
Table 2
Naph), 135.3 (t, JPC ¼ 19.5 Hz, ipso-Ph), 140.9 (t, JPC ¼ 14.4 Hz, ipso-
Naph), 141.8 (t, JPC ¼ 4.4 Hz, Naph). 31P{1H} NMR (121.7 MHz,
Crystallographic data for cis-1, cis-4, and trans-4.
CD2Cl2):
d
ꢀ19.4 (s). Anal. Calcd for C22H16P2: C, 77.19; H, 4.71.
Cis-1
Cis-4
Trans-4
Found: C, 77.04; H, 4.57.
Formula
a/Å
b/Å
C22H16P2
8.7940 (2)
10.1680 (2)
11.2210 (3)
64.086 (1)
77.000 (1)
68.044 (2)
834.73 (3)
2
C47H38Au4Cl10P4
17.9392 (16)
14.4197 (13)
20.3615 (18)
90.0
91.855 (1)
90.0
5264.3 (8)
4
C22H16Au2Cl2P2
14.6492 (8)
7.9741 (4)
19.6241 (10)
90.0
110.5853 (12)
90.0
2146.00 (19)
4
4.3. Photochemical synthesis of cis-1
c/Å
a
/deg
/deg
Trans-1 (770 mg, 2.25 mmol) was dissolved in hexane (60 mL) at
60 ꢁC and the hexane solution was irradiated with a mercury arc
lamp for 6 h at 0 ꢁC to give cis-1 as a white precipitate. The product
was separated and washed with hexane, then dried in vacuo to give
a white powder of cis-1 (726 mg, 94%).
b
g
/deg
V/Å3
Z
Formula weight
Space group
Temp/ꢁC
342.29
1869.02
P21/n (No. 14)
ꢀ173
807.12
Pꢀ1 (No. 2)
P21/n (No. 14)
ꢀ100
ꢀ73
l
/Å
Dcalcd/g cmꢀ3
(Mo K
)/mmꢀ1
(I))
0.71069
1.362
0.71073
2.358
11.776
0.0325
0.0865
0.71075
2.498
4.4. Synthesis of (m-cis-1)-[W(CO)5]2 (cis-2)
m
a
s
0.259
0.0356
0.0952
14.061
0.0439
0.0876
A solution of W(CO)6 (68 mg, 0.19 mmol) in THF was irradiated
with a mercury arc lamp for 6 h and then cis-1 (24 mg, 0.07 mmol)
was added. After stirring the solution overnight, the mixture was
found to contain a monotungsten complex [W(cis-1)(CO)5] as well
as the ditungsten complex cis-2 in a 1:1 ratio. To complete the
reaction, THF was removed in vacuo and the residue was re-
dissolved in CH2Cl2 (5 mL) and stirred for 2 days. After the
solvent was removed in vacuo, the products were extracted with
ether. The extracts were loaded into an Al2O3 column and eluted
with CH2Cl2. A band containing cis-2 was collected, and dried in
vacuo. The residue was washed with hexane and dried again to give
a white powder of cis-2 (52 mg, 75%). The spectroscopic data were
identical to those reported previously [2].
R1 (I > 2
a
wR2
P
P
wR2 ¼ f ½wðFo2 ꢀ Fc2Þ2ꢃ= ½wðFo2Þ2ꢃg1=2
;
w ¼ 1=½s2ðFo2Þ þ ðapÞ2 þ bpꢃ;
a
p ¼ ðFo2 þ 2Fc2Þ=3. a and b values for cis-1, cis-4, and trans-4 are 0.0459 and 0.7421,
0.0550 and 0.0, and 0.0117 and 37.7773, respectively.
DIP2030 imaging-plate-based diffractometer at 200 K for cis-1,
a Bruker APEX-II Ultra CCD-based diffractometer at 100 K for cis-4,
and a Rigaku SCX mini CCD-based diffractometer at 173 K for trans-
4. The structures were solved by the direct method and expanded
using Fourier techniques. Non-hydrogen atoms were refined
anisotropically, while hydrogen atoms were located at ideal posi-
tions and refined isotropically. All calculations were performed
using the SHELXL-97 crystallographic software package [25]. A
summary of data collection and structure refinement details is
provided in Table 2.
4.5. Synthesis of (m-cis-1)-[AuCl]2 (cis-4)
A Schlenk tube was charged with cis-1 (19 mg, 0.056 mmol),
AuCl(tht) (36 mg, 0.11 mmol), and CH2Cl2. The mixture was stirred
for 2 h, after which the solvent was removed. The cis-4 obtained
was washed 5 times with ether (5 mL aliquots), and dried in vacuo.
Acknowledgments
Yield: 44 mg (97%). 1H NMR (300.5 MHz, CDCl3):
d 7.05 (t, JHH and
This work was supported by Grant-in-Aid for Scientific Research
Nos. 22550061 and 23105533 from the Ministry of Education,
Culture, Sports, Science and Technology, Japan. The measurements
of microanalysis and X-ray diffraction analysis were made using
PerkineElmer CHNS 2400II and Bruker APEX-II Ultra, respectively,
at the Natural Science Center for Basic Research and Development
(N-BARD), Hiroshima University.
JPH ¼ 7.6 Hz, 4H, Ph), 7.20e7.32 (m, 6H, Ph), 7.80 (t, JHH ¼ 7.5 Hz, 2H,
3,6-Naph), 7.97 (dd, JHH or JPH ¼ 6.3 Hz, JHH or JPH ¼ 12.7 Hz, 2H, 2,7-
Naph), 8.20 (d, JHH ¼ 8.1 Hz, 2H, 4,5-Naph). 13C{1H} NMR (75.6 MHz,
CDCl3):
d
128.3 (t, JPC ¼ 6.5 Hz, 3,6-Naph), 128.6 (t, JPC ¼ 5.6 Hz, m-
Ph), 131.7 (s, 4,5-Naph), 132.3 (s, p-Ph), 133.5 (t, JPC ¼ 8.4 Hz, 2,7-
Naph), 135.1 (t, JPC ¼ 8.7 Hz, o-Ph). 31P{1H} NMR (121.7 MHz,
CD2Cl2): d 24.7 (s). Anal. Calcd for C22H16Au2Cl2P2: C, 32.74; H, 2.00.
Found: C, 32.53; H, 1.94.
Appendix. Supplementary material
4.6. Synthesis of ( -trans-1)-[AuCl]2 (trans-4)
m
CCDC 826280, 826281, and 826282 contain the supplementary
crystallographic data cis-1, trans-4, and cis-4, respectively. These
data can be obtained free of charge from The Cambridge Crystal-
lographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
The trans analog was prepared in a manner similar to that previ-
ously described, but starting from trans-1 (18 mg, 0.053 mmol) and
AuCl (THT) (42 mg, 0.13 mmol). Yield: 41 mg (96%). 1H NMR
(300.5 MHz, CDCl3):
d
7.25e7.50 (m, 8H, Ph), 7.60 (t, JHH ¼ 7.1 Hz, 2H,
References
p-Ph), 7.91 (t, JHH ¼ 7.7 Hz, 2H, 3,6-Naph), 8.07 (dd, JHH or JPH ¼ 6.9 Hz,
JHH or JPHP ¼ 12.9 Hz, 2H, 2,7-Naph), 8.32 (d, JHH ¼ 8.4 Hz, 2H, 4,5-
[1] For recent examples, see (a) J. Fornies, C. Fortuno, S. Ibanez, A. Martin, Inorg.
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Naph). 13C{1H} NMR (75.6 MHz, CDCl3):
d
128.7 (t, JPC ¼ 6.5 Hz, 3,6-
Naph), 130.2 (t, JPC ¼ 5.6 Hz, m-Ph), 132.5 (s, 4,5-Naph), 133.8 (t,
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P
{1H} NMR (121.7 MHz, CD2Cl2):
d 34.0 (s). Anal. Calcd for
C22H16Au2Cl2P2: C, 32.74; H, 2.00. Found: C, 32.73; H, 1.93.
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of trans-4. Measurements were conducted using a Mac Science

Y. Teramoto et al. / Journal of Organometallic Chemistry 696 (2011) 3402e3407
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