Synthesis and molecular structures of dinuclear complexes with 1,2-dihydro-1,2-diphenyl-naphtho[1,8-c,d]1,2-diphosphole as a bridging ligand

Article abstract of DOI:10.1016/j.jorganchem.2004.05.022

A bisphosphine in which a PhP-PPh bond bridges 1,8-positions of naphthalene, 1,2-dihydro-1,2-diphenyl-naphtho[1,8-cd]-1,2-diphosphole (1), was used as a bridging ligand for the preparation of dinuclear group 6 metal complexes. Free trans-1, a more stable isomer having two phenyl groups on phosphorus centers mutually trans with respect to a naphthalene plane, was allowed to react with two equivalents of M(CO ₅(thf) (M=W, Mo, Cr) at room temperature to give dinuclear complexes (OC)₅M(μ-trans-1)M(CO)₅ (M=W (2a), Mo (2b), Cr (2c)). The preparation of the corresponding dinuclear complexes bridged by the cis isomer of 1 was also carried out starting from the free trans-1 in the following way. Mono-nuclear complexes M(trans-1)(CO ₅ (M=W (3a), Mo (3b), Cr (3c)) which had been prepared by a reaction of trans-1 with one equivalent of the corresponding M(CO ₅(thf) (M=W, Mo, Cr) complex, were heated in toluene, wherein a part of the trans-3a-c was converted to their respective cis isomer M(cis-1)(CO)5. Each cis trans mixture of the mono-nuclear complexes 3a-c was treated with the corresponding M(CO)₅(thf) to give a cis trans mixture of the respective dinuclear complexes 2a-c. The cis isomer of the ditungsten complex 2a was isolated, and its molecular structure was confirmed by X-ray analysis, showing a shorter W···W distance of 5.1661(3)A? than that of 5.8317(2) A? in trans-2a.

Full text of DOI:10.1016/j.jorganchem.2004.05.022

Journal of Organometallic Chemistry 689 (2004) 2624–2632
www.elsevier.com/locate/jorganchem
Synthesis and molecular structures of dinuclear complexes with
1,2-dihydro-1,2-diphenyl-naphtho[1,8-c,d]1,2-diphosphole as a
bridging ligand
*
*
Tsutomu Mizuta , Satoru Kunikata, Katsuhiko Miyoshi
Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
Received 16 April 2004; accepted 18 May 2004
Available online 2 July 2004
Abstract
A bisphosphine in which a PhP–PPh bond bridges 1,8-positions of naphthalene, 1,2-dihydro-1,2-diphenyl-naphtho[1,8-cd]-1,2-
diphosphole (1), was used as a bridging ligand for the preparation of dinuclear group 6 metal complexes. Free trans-1, a more stable
isomer having two phenyl groups on phosphorus centers mutually trans with respect to a naphthalene plane, was allowed to react
with two equivalents of M(CO)5(thf) (M=W, Mo, Cr) at room temperature to give dinuclear complexes (OC)5M(l-trans-1)M(CO)5
(M=W (2a), Mo (2b), Cr (2c)). The preparation of the corresponding dinuclear complexes bridged by the cis isomer of 1 was also
carried out starting from the free trans-1 in the following way. Mono-nuclear complexes M(trans-1)(CO)5 (M=W (3a), Mo (3b), Cr
(3c)) which had been prepared by a reaction of trans-1 with one equivalent of the corresponding M(CO)5(thf) (M=W, Mo, Cr) com-
plex, were heated in toluene, wherein a part of the trans-3a–c was converted to their respective cis isomer M(cis-1)(CO)5. Each cis
trans mixture of the mono-nuclear complexes 3a–c was treated with the corresponding M(CO)5(thf) to give a cis trans mixture of the
respective dinuclear complexes 2a–c. The cis isomer of the ditungsten complex 2a was isolated, and its molecular structure was con-
˚
˚
firmed by X-ray analysis, showing a shorter Wꢀ ꢀ ꢀW distance of 5.1661(3) A than that of 5.8317(2) A in trans-2a.
ꢀ 2004 Elsevier B.V. All rights reserved.
Keywords: Bisphosphine; Dinuclear complex; Tungsten; Molybdenum; Chromium
1. Introduction
ments [2,3]. In these dinuclear complexes, the two metal
centers in close proximity have a potential to facilitate
the simultaneous or consecutive activation and transfor-
mation of substrate molecules.
The chemistry of dinuclear complexes is rapidly
growing, which has been brought about by significant
progress in a synthetic methodology. The most success-
ful approach to the synthesis of dinuclear complexes is
to use a bridging ligand [1]. Phosphido groups,
R2Pꢁ(Fig. 1(a)), and bis(diorganophosphino)methanes,
R2PCH2PR2 (Fig. 1(b)), have been widely used as a
bridging ligand because of their ability to form a stable
phosphorus-metal bond with a variety of metal frag-
Bisphosphines, R2P–PR2, are also a promising li-
gand which can lock together two metal centers in
close proximity as shown in Fig. 1(c). Since early
1960s, bisphosphines have been used for syntheses of
a variety of dinuclear complexes [4,5]. However, such
examples are considerably smaller in number than the
dinuclear complexes having the R2Pꢁ and/or
R2PCH2PR2 ligands as the bridge(s). The slow progress
concerning the R2P–PR2-bridged dinuclear complexes
is partly due to a relatively weak P–P bond of the bis-
phosphine ligand.
*
Corresponding authors. Tel.: +81-82-424-7420; fax: +81-82-424-
0729.
E-mail address: mizuta@sci.hiroshima-u.ac.jp (T. Mizuta).
0022-328X/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.05.022

T. Mizuta et al. / Journal of Organometallic Chemistry 689 (2004) 2624–2632
2625
plane. The ligand 1 (trans-1) reacts with two equivalents
of M(CO)5(thf) (M=W, Mo, Cr) at room temperature
to give an expected product, (OC)5M(l-trans-1)M(CO)5
(M=W (2a), Mo (2b), Cr (2c)) in almost quantitative
yields. 31P{1H} NMR spectra of these complexes show a
singlet at 30.4 ppm with satellites due to 183W(I=1/2,
R
P
R
P
R
R
R
R
R
R
R
R
P
P
P
a
M
M
M
M
M
M
b
c
Fig. 1. Phosphorus-based bridging ligands which can lock together
two metal centers in close proximity.
2
1JPW =166 Hz, JPW =81 Hz) for the tungsten complex
2a, and a singlet at 49.1 and 71.7 ppm for the molybdenum
and chromium complexes, 2b and 2c, respectively. For the
tungsten complex 2a, the molecular structure was con-
firmed by the X-ray analysis. An ORTEP drawing is
shown in Fig. 3, where trans-1 bridges the two W(CO)5
Recently, our group reported a novel bisphosphine li-
gand 1, in which two phosphorus atoms are locked with
a robust naphthalene group [6], rendering the phospho-
rus–phosphorus bond fairly stable. Here we report, the
synthesis of dinuclear complexes bridged by the robust
phosphorus–phosphorus bond.
˚
fragments. A P1–P2 distance of 2a is 2.270(1) A which is
˚
slightly longer than 2.2240(6) and 2.2246(6) A for those
of two independent molecules in the crystal of trans-1.
The P1–P2 bond of 2a in Fig. 3 is twisted by 15.7ꢁ with re-
spect to the naphthalene plane, whereas the P1–P2 bond
of free trans-1 in Fig. 2 is almost parallel to the plane.
The reason for the deformation is not clear at present.
Each of the two phosphorus centers P1 and P2 in Fig. 3
forms a tetrahedral geometry with usual W–P distances,
Ph
Ph
P
P
1
˚
2.5335(9) and 2.5224(9) A for W1–P1 and W2–P2, respec-
tively. A separation between the two tungsten centers
˚
amounts to 5.8317(2) A, which is significantly longer than
2. Results and discussion
ꢁ
˚
3–4 A found in the R2P - and/or R2PCH2PR2-bridged
complexes shown in Fig. 4 [9,10]. Since the trans disposi-
tion of the two tungsten fragments makes their separation
large, synthesis of the cis isomer was attempted.
1,2-dihydro-1,2-diphenyl-naphtho[1,8-cd]-1,2-diphos-
phole, 1, was prepared from dilithionaphthalene and
dichlorophenylphosphine [6,7]. The molecular structure
determined by X-ray analysis is shown in Fig. 2 [8], where
two phenyl groups on the phosphorus atoms adopt a mu-
tually trans disposition with respect to a naphthalene
The cis isomer of 2, (OC)5M(l-cis-1)M(CO)5, would
be obtained, if free cis-1 were used in place of trans-1.
Fig. 3. An ORTEP drawing of (OC)5W(l-trans-1)W(CO)5 (trans-2a)
˚
with 50% thermal ellipsoids. The selected bond distances (A) and
Fig. 2. An ORTEP drawing of 1 with 50% thermal ellipsoids. This is
for one of the two independent molecules found in the crystal 1. The
angles (ꢁ) are W1–P1 2.5335(9), W2–P2 2.5224(9), P1–P2 2.270(1), P1–
C1 1.819(4), P1–C11 1.837(4), P2–C8 1.828(4), P2–C17 1.833(4), W1–
P1–P2 123.54(4), W2–P2–P1 122.28(4), P2–P1–C1 92.3(1), P2–P1–C11
99.4(1), C1–P1–C11 101.6(2), P1–P2–C8 91.6(1), P1–P2–C17 101.3(1),
C8–P2–C17 101.7(2).
˚
selected bond distances (A) and angles (ꢁ) are P1–P2 2.2240(6), P1–C1
1.830(2), P1–C11 1.841(2), P2–C8 1.838(2), P2–C17 1.837(2), P2–P1–
C1 93.83(5), P2–P1–C11 98.90(5), C1–P1–C11 102.40(7), P1–P2–C8
93.19(5), P1–P2–C17 101.50(5), C8–P2–C17 103.81(7).

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T. Mizuta et al. / Journal of Organometallic Chemistry 689 (2004) 2624–2632
although the Ph–Ph repulsion is originally present as
2-
Ph2
Ph2
P
P
shown in Fig. 5(b). Thus, the additional steric repulsion
introduced in Fig. 5(a) will reduce the relative stability
of the trans isomer. In addition, the fragment introduced
to the cis isomer eliminates the lone pair repulsion which
was partly responsible for the relative instability of free
cis-1. Consequently, the thermal equilibrium is expected
to be shifted to some extent toward the cis isomer. Such
a situation will be accomplished by the introduction of
only one bulky metal fragment such as M(CO)5 to the
free ligand 1.
(OC)4W
W(CO)4
W(CO)4
(OC)4W
P
P
Ph2
Ph2
4.102 Å
3.026 Å
+
+
Ph
2P
PPh2
Ph
2P
Ph
P
2
Cp
Cp
F
Cp
Cp
W
W
W
W
OC
F
CO
C
O
OC
CO
OC
CO
2.945 Å
4.158 Å
A reaction of trans-1 with one equivalent of
M(CO)5(thf) (M=W, Mo, Cr) at room temperature
gave M(trans-1)(CO)5 (M=W (3a), Mo (3b), Cr (3c)).
31P{1H} NMR spectra of these complexes exhibit two
doublets. The phosphorus atoms coordinating to the
metal center were observed at 13.1, 33.7 and 52.0 ppm
for trans-3a–c, respectively, whereas non-coordinating
ones were observed at ꢁ8.8, ꢁ8.5, and ꢁ8.1 ppm, re-
spectively, which are in accord with ꢁ8.2 ppm for free
trans-1. For the tungsten complex trans-3a, its structure
was confirmed by the X-ray analysis as shown in Fig. 6,
where one W(CO)5 fragment is attached to trans-1. A
noteworthy point is that a carbonyl group C24–O2 of
the W(CO)5 fragment is directed to the phenyl group
on the neighboring phosphorus center. Judging from a
Fig. 4. Tungsten–tungsten distances for some dinuclear tungsten
complexes bridged by Ph2Pꢁ or Ph2PCH2PPh2 groups.
The cis configuration of the free ligand 1 is attained in
principle through the inversion of configuration at a
phosphorus center of trans-1. Since the inversion barrier
has been estimated to be ca. 25 kcal/mol for the bisphos-
phines, which is lower by ca. 10 kcal/mol than for the
usual mono phosphines [11,12], heating of free trans-1
in toluene was carried out with an expectation of the in-
version of the configuration. After heating overnight at
80 ꢁC, 31P{1H} NMR spectrum of the reaction mixture
indicated that a trace of a new signal appeared at ꢁ19.7
ppm which is probably assigned to cis-1. However, the
new signal did not increase in intensity any more by pro-
longed heating, indicating that the cis–trans isomeriza-
tion has reached to a thermal equilibrium. The relative
instability of cis-1 is mainly due to a steric repulsion be-
tween the two phenyl groups disposed at the same side
with respect to the naphthalene plane. In addition, a re-
pulsive interaction is also expected between two lone
pairs on the phosphorus atoms of cis-1, although it is re-
ported to be faint owing to a significant s character of
the lone pair on the phosphorus [13,14]. Such steric
and lone pair repulsions are absent in trans-1, as is evi-
dent in Fig. 2.
˚
distance of 3.001(3) A between O2 and a mean plane
of the phenyl group, the W(CO)5 fragment apparently
exerts a steric repulsion on the phenyl group as expect-
Here, assuming that a bulky fragment is introduced
to one of the two phosphorus atoms of free trans-1,
the introduced fragment exerts a steric repulsion on
the phenyl group at the vicinal phosphorus center as de-
picted in Fig. 5(a). On the other hand, for a correspond-
ing cis isomer, the bulky fragment does not make any
repulsion against the phenyl group on the vicinal center,
repulsion
Ph
P
P
P
P
Ph
Ph
Fig. 6. An ORTEP drawing of W(trans-1)(CO)5 (trans-3a) with 50%
˚
repulsion
Ph
thermal ellipsoids. The selected bond distances (A) and angles (ꢁ) are
(a)
(b)
W1–P1 2.5242(6), P1–P2 2.2409(8), P1–C1 1.826(2), P1–C11 1.841(2),
P2–C8 1.832(2), P2–C17 1.836(2), W1–P1–P2 125.70(3), P2–P1–C1
94.99(8), P2–P1–C11 97.10(7), C1–P1–C11 103.3(1), P1–P2–C8
91.66(8), P1–P2–C17 104.95(7), C8–P2–C17 101.2(1).
Fig. 5. A schematic representation of steric repulsions: (a) between a
Ph group and a bulky fragment in the trans form; (b) between the two
phenyl groups in the cis form.

T. Mizuta et al. / Journal of Organometallic Chemistry 689 (2004) 2624–2632
2627
ed. The P2–P1–W1 angle, as a result, opens up to
125.70(3)ꢁ, and a P1–P2–C17(Ph) angle of 104.95(7)ꢁ is
greater than 98.10(7)ꢁ and 101.50(7)ꢁ for the P–P–Ph an-
gles of free trans-1.
30 times of recycling, and characterized as cis-2a by the
X-ray analysis as shown in Fig. 8. It is highly probable
that the cis-2a isomer is formed by the simple reaction
of the W(CO)5 with the cis isomer of 3a. Thus, the new
two doublets in Fig. 7 should be assigned to cis-3a. The
molecular structure of cis-2a in Fig. 8 indicates that the
two phenyl groups adopt a stacking form to minimize
a steric congestion between them. However, judging
from a short separation between these two phenyl planes,
the steric repulsion is conceivable between them as
for the free cis ligand. For example, ipso carbon atoms
of the phenyl groups, C11 and C17, face a mean plane
of their respective counterpart with distances of 2.88(1)
The mono-nuclear trans-3a–c species thus obtained
were heated in toluene. The 31P{1H} NMR spectra of
the reaction mixture are shown for trans-3a in Fig. 7,
which indicates that new two doublets coupled with each
other appear at ꢁ1.7 and 2.7 ppm (1JP–P =238 Hz). The
new signal at 2.7 ppm is assigned to the phosphorus cen-
ter bonding to the W(CO)5 fragment, because it accom-
panies satellites due to 183W. Unfortunately, separation
of this species from trans-3a was not successful, but
following results (vide infra) clearly indicate that this spe-
cies is cis-3a. Similar thermal trans–cis conversion was
carried out for the molybdenum and chromium analogs,
trans-3b and -3c. In the 31P{1H} NMR spectra, new dou-
blets were observed at ꢁ6.6 and 23.2 ppm (1JP–P =243
Hz) for the former complex and at ꢁ9.7 and 47.3 ppm
(1JP–P =253 Hz) for the latter. The relative intensities of
trans to cis isomers were similar to that of 3a.
The cis–trans mixtures of 3 were then allowed to react
with another equivalent of the corresponding metal frag-
ment, M(CO)5(thf) (M=W, Mo, Cr). The 31P{1H}
NMR spectra of the products show that, in addition to
the signals at 29.9, 49.1, and 71.7 ppm due to trans-2a–
c, respectively, new singlets were observed at 29.4, 46.5,
and 68.0 ppm, respectively. For the tungsten case, we
managed to isolate the new species having a signal at
29.4 ppm by means of a preparative scale HPLC over
˚
and 2.91(1) A, respectively, which are significantly small-
˚
er than the van der Waals contact distance of 3.40 A.
The two bulky tungsten fragments in Fig. 8 are sepa-
˚
˚
rated by 5.1661(3) A, which is shorter than 5.8317(2) A
of trans-2a as expected, but it is still considerably longer
than those of the complexes shown in Fig. 4. The reason
for the fairly large Wꢀ ꢀ ꢀW separation in cis-2a is that the
carbonyl group C25–O3 on the W1 center are already in
touch with the two carbonyl groups C29–O7 and C32–
O10 on the W2 center, as is evident in the distances be-
tween these carbonyl groups, for example, O3ꢀ ꢀ ꢀC29,
˚
˚
3.082(9) A ; O3ꢀ ꢀ ꢀC32, 3.044(10) A. It seems crucial to
reduce the steric bulkiness of the two metal fragments
Fig. 8. An ORTEP drawing of (OC)5W(l-cis-1)W(CO)5 (cis-2a) with
˚
50% thermal ellipsoids. The selected bond distances (A) and angles (ꢁ)
are W1–P1 2.535(1), W2–P2 2.514(2), P1–P2 2.280(2), P1–C1 1.817(6),
P1–C11 1.841(6), P2–C8 1.825(6), P2–C17 1.842(7), W1–P1–P2
124.11(7), W2–P2–P1 120.90(7), P2–P1–C1 91.3(2), P2–P1–C11
101.5(2), C1–P1–C11 100.8(3), P1–P2–C8 91.2(2), P1–P2–C17
103.9(2), C8–P2–C17 106.3(3).
Fig. 7. 31P{1H} NMR spectra of 3a in toluene: (a) before heating; (b)
after heating.

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T. Mizuta et al. / Journal of Organometallic Chemistry 689 (2004) 2624–2632
in order to let them come closer. Such an attempt is now
under way.
128.1 (t, JPC =5.0 Hz), 129.1 (t, JPC =4.0 Hz), 130.7
(s), 131.5 (s), 133.1 (t, JPC =5.0 Hz), 133.5 (t, JPC =7.6
Hz), 133.7 (t, JPC =8.1 Hz), 135.3 (t, JPC =18.3 Hz),
136.9 (t, JPC =15.6 Hz), 138.7 (t, JPC =5.6 Hz), 195.7
(t, JPC =2.8 Hz, JCW =126 Hz, cis-CO), 197.3 (t,
JPC =13.7 Hz, trans-CO). 31P{1H} NMR (d, in CDCl3):
3. Experimental
2
3.1. General remarks
30.4 (1JPW =166.4 Hz, JPW =81.4 Hz)
All reactions were carried out under an atmosphere
of dry nitrogen using Schlenk tube techniques. THF
was distilled from sodium/benzophenone and toluene
was distilled from sodium metal. These purified solvents
were stored under an N2 atmosphere. CHCl3 and other
reagents were used as received. Trans-1 was prepared ac-
cording to previously described methods [6].
3.3. Synthesis of (OC)5Mo(l-trans-1)Mo(CO)5 (2b)
2b was prepared as described above for 2a, using
1
Mo(CO)6. H NMR (d, in CDCl3): 7.20–7.42 (m, 10H,
Ph), 7.83 (t, JHH =7.1 Hz, JPH =8.1 Hz, 2H, 2,7-naph),
8.03 (m, 2H, 3,5-naph), 8.16 (d, JHH =8.3 Hz, 2H, 4,5-
naph). 13C{1H} NMR (d, in CDCl3): 128.1 (t, JPC =4.9
Hz), 129.0 (t, JPC =4.0 Hz), 130.4 (s), 131.3 (s), 133.0
(t, JPC =4.3 Hz), 133.3 (t, JPC =7.3 Hz), 133.4
(t, JPC =8.7 Hz), 135.5 (t, JPC =15.0 Hz), 137.2 (t,
JPC =11.6 Hz), 138.8 (t, JPC =4.3 Hz), 204.4 (t,
JPC =4.0 Hz, cis-CO), 209.0 (t, JPC =13.8 Hz, trans-
CO). 31P{1H} NMR (d, in CDCl3): 49.1.
IR spectra were recorded on a Perkin–Elmer Spec-
trum One spectrometer. NMR spectra were recorded
1
on a JEOL LA-300 spectrometer. H 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
2400CHN elemental analyzer.
a
Perkin–Elmer
3.4. Synthesis of (OC)5Cr(l-trans-1)Cr(CO)5 (2c)
Photolysis was carried out with Pyrex-glass-filtered
emission from a 400 W mercury arc lamp (Riko-Kagaku
Sangyo UVL-400P). The used emission-lines (nm) and
their relative intensities (in parenthesis) were as follows:
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). Preparative-scale
GPC was performed with a recycling HPLC system (Ja-
pan Analytical Industry Model LC-908) with JAIGEL-
1H (20 mm ID·600 mm; exclusion limit: 1.0·103) and
ꢁ2H (20 mm ID·600 mm; exclusion limit: 5.0·103)
columns.
2c was prepared as described above for 2a, using
1
Cr(CO)6. H NMR (d, in CDCl3): 7.35–7.47 (m, 10H,
Ph), 7.83 (t, JHH =7.1 Hz, JPH =8.2 Hz, 2H, 2,7-naph),
8.04 (m, 2H, 3,5-naph), 8.15 (d, JHH =8.3 Hz, 2H, 4,5-
naph). 13C{1H} NMR (d, in CDCl3): 128.0 (t, JPC =4.9
Hz), 129.2 (t, JPC =4.0 Hz), 130.5 (s), 131.4 (s), 132.9
(t, JPC =6.1 Hz), 133.0 (t, JPC =4.9 Hz), 133.3
(t, JPC =7.3 Hz), 134.5 (t, JPC =15.0 Hz), 136.6 (t,
JPC =12.0 Hz), 137.9 (t, JPC =5.5 Hz), 215.1 (t,
JPC =5.5 Hz, cis-CO), 220.5 (t, JPC =2.5 Hz, trans-
CO). 31P{1H} NMR (d, in CDCl3): 71.7.
3.2. Synthesis of (OC)5W(l-trans-1)W(CO)5 (2a)
3.5. Synthesis of W(trans-1)(CO)5 (3a)
W(CO)6 (510 mg, 1.4 mmol) dissolved in THF (40
mL) was irradiated by a mercury lamp for 2.5 h to gen-
erate W(CO)5(thf) in situ. To a W(CO)5(thf) solution
thus obtained was added 1 (174 mg, 0.51 mmol) dis-
solved in a minimum amount of THF. The solution
was stirred overnight, and THF was removed in vacuo.
The residue was dissolved in CHCl3 and passed through
a short silica gel column (2 cm ID·2 cm). Since the
product was contaminated with unreacted W(CO)6
which was difficult to remove by a standard column
technique, the product was purified by a preparative
scale GPC column. 2a was obtained almost quantita-
tively. Anal. Calcd for C32H16O10P2W2: C, 38.82; H,
1.63. Found: C, 38.94; H, 1.61. IR (mCO, cmꢁ1, in
W(CO)6 (970 mg, 2.8 mmol) dissolved in THF was ir-
radiated by a mercury lamp for 2.5 h. To a W(CO)5(thf)
solution thus obtained was added trans-1 (660 mg, 1.9
mmol) dissolved in a minimum amount of THF. The so-
lution was stirred for 4 h, and THF was removed in vac-
uo. The residue was dissolved in CHCl3 and passed
through a short silica gel column (2 cm ID·2 cm).
The product 3a was separated from 2a and unreacted
W(CO)6 by the preparative scale GPC column. Yield:
842 mg (66%). IR (mCO, cmꢁ1, in THF): 2072, 1940.
1H NMR (d, in CDCl3): 7.10 (m, 2H, Ph), 7.15–7.40
(m, 8H, Ph), 7.59 (m, JHH =7.2 Hz, JHH =8.1 Hz,
JPH =2.4 Hz, 1H, 6-naph), 7.76 (m, JHH =7.2 Hz,
JHP =7.2 Hz, JPH =0.9 Hz, 1H, 7-naph), 7.89 (m,
JHH =7.0 Hz, JHH =8.1 Hz, JPH =2.9 Hz, 1H, 3-naph),
7.99 (d, JHH =8.3 Hz, 1H, 5-naph), 8.13 (bd, JHH =8.2
Hz, 1H, 4-naph), 8.30 (m, JHH =7.7 Hz, JPH =0.8 Hz,
1H, 7-naph). 13C{1H} NMR (d, in CDCl3): 127.3 (d,
1
THF): 2070, 1950. H NMR (d, in CDCl3): 7.25–7.45
(m, 10H, Ph), 7.85 (t, JHH =7.1 Hz, JPH =6.9 Hz, 2H,
2,7-naph), 8.01 (m, 2H, 3,5-naph), 8.17 (d, JHH =8.2
Hz, 2H, 4,5-naph). 13C{1H} NMR (d, in CDCl3):

T. Mizuta et al. / Journal of Organometallic Chemistry 689 (2004) 2624–2632
2629
JPC =9.3 Hz), 128.0 (d, JPC =8.7 Hz), 128.4 (d, JPC =9.3
Hz), 128.8 (s), 129.0 (dd, JPC =1.9 Hz, JPC =8.1 Hz),
129.3 (s), 130.1 (dd, JPC =8.1 Hz, JPC =10.0 Hz), 130.6
(d, JPC =1.3 Hz), 130.7 (d, JPC =1.9 Hz), 132.4 (dd,
JPC =4.4 Hz, JPC =26.1 Hz), 133.3 (d, JPC =6.2 Hz),
133.9 (dd, JPC =1.2 Hz, JPC =11.2 Hz), 134.6 (d,
JPC =23.6 Hz), 134.9 (d, JPC =5.6 Hz), 135.2 (d,
JPC =5.5 Hz), 138.0 (dd, JPC =2.5 Hz, JPC =22.4 Hz),
138.4 (dd, JPC =17.4 Hz, JPC =32.9 Hz), 139.6 (d,
JPC =23.0 Hz), 140.4 (dd, JPC =1.9 Hz, JPC =8.7 Hz),
196.0 (d, JPC =6.9 Hz, JCW =125.3 Hz), 198.5 (d,
JPC =24.2 Hz). 31P{1H} NMR (d, in CDCl3): ꢁ8.8
(JPP =219.9 Hz), 13.1 (JPP =219.9 Hz, JPW =235.7 Hz).
133.5 (dd, JPC =1.3 Hz, JPC =10.6 Hz), 133.9 (d,
JPC =22.9 Hz), 135.2 (d, JPC =5.6 Hz, JPC =22.9 Hz),
138.0 (d, JPC =16.8 Hz, JPC =3.7 Hz), 138.2 (dd,
JPC =18.0 Hz, JPC =28.0 Hz), 139.6 (d, JPC =23.0 Hz),
140.4 (dd, JPC =1.8 Hz, JPC =8.0 Hz), 215.6 (d,
JPC =12.4 Hz, cis-CO), 221.0 (d, JPC =5.6 Hz, trans-
CO). 31P{1H} NMR (d, in CDCl3): ꢁ8.1 (JPP =228
Hz), 52.0 (JPP =227 Hz).
3.8. Conversion of trans-3 to cis-3
Tungsten complex trans-3a, molybdenum complex
trans-3b, and chromium complex trans-3c were each dis-
solved in toluene and sealed in NMR tubes, which were
dipped in an oil bath at 100 ꢁC and 31P{1H} NMR spec-
tra were recorded at appropriate intervals. Since cis-3a–c
formed were not isolated successfully, only 31P{1H}
NMR data were given here. The tungsten complex:
31P{1H} NMR (d, in toluene): ꢁ1.7 (JPP =238 Hz,
JPW =226 Hz), 2.7 (JPP =236 Hz). The molybdenum
complex: 31P{1H} NMR (d, in toluene): ꢁ6.6
(JPP =243 Hz), 23.2 (JPP =243 Hz). The chromium com-
plex: 31P{1H} NMR (d, in toluene): ꢁ9.1 (JPP =252 Hz),
47.3 (JPP =252 Hz).
3.6. Synthesis of Mo(trans-1)(CO)5 (3b)
3b was prepared as described above for 3a, using
Mo(CO)6. IR (mCO, cmꢁ1, in THF): 2073, 1949. 1H
NMR (d, in CDCl3): 7.08 (m, 2H, Ph), 7.18–7.37 (m,
8H, Ph), 7.59 (m, JHH =7.3 Hz, JHH =8.1 Hz, JPH =2.6
Hz, 1H, 6-naph), 7.75 (t, JHH =7.2 Hz, JHP =7.2 Hz,
1H, 7-naph), 7.87 (m, JHH =7.1 Hz, JHH =7.9 Hz,
JPH =2.7 Hz, 1H, 3-naph), 7.98 (d, JHH =8.3 Hz, 1H,
5-naph), 8.13 (d, JHH =8.1 Hz, 1H, 4-naph), 8.30 (m,
JHH =7.1 Hz, JPH =9.5 Hz, 1H, 2-naph). 13C{1H}
NMR (d, in CDCl3): 127.3 (d, JPC =9.4 Hz), 128.0 (d,
JPC =8.7 Hz), 128.4 (d, JPC =8.7 Hz), 128.7 (s), 128.9
(dd, JPC =1.2 Hz, JPC =8.1 Hz), 129.0 (s), 130.1 (dd,
JPC =8.1 Hz, JPC =10.6 Hz), 130.4 (d, JPC =1.3 Hz),
130.6 (d, JPC =1.9 Hz), 132.3 (dd, JPC =3.7 Hz,
JPC =26.1 Hz), 133.3 (d, JPC =6.2 Hz), 133.7 (d,
JPC =12.4 Hz), 134.8 (d, JPC =23.0 Hz), 134.9 (d,
JPC =5.0 Hz, JPC =22.3 Hz), 138.2 (dd, JPC =3.1 Hz,
JPC =17.8 Hz), 138.6 (dd, JPC =16.8 Hz, JPC =27.4
Hz), 139.7 (d, JPC =23.6 Hz), 140.5 (dd, JPC =1.8 Hz,
JPC =7.4 Hz), 204.7 (d, JPC =9.3 Hz, cis-CO), 209.6 (d,
JPC =24.8 Hz, trans-CO). 31P{1H} NMR (d, in CDCl3):
ꢁ8.5 (JPP =220 Hz), 33.7 (JPP =220 Hz).
3.9. Synthesis of (OC)5W(l-cis-1)W(CO)5 (cis-2a)
Trans-3a (235 mg, 0.35 mmol) was dissolved in tolu-
ene and heated at 100 ꢁC for 24 h. To a mixture of the
cis and trans isomers was added W(CO)5(thf) generated
from W(CO)6 (177 mg, 0.5 mmol). After stirring over-
night, the solvents were removed in vacuo. The residue
was passed through a short sillica gel column. The efflu-
ent was a 1:3 mixture of cis–trans-2a. Complete separa-
tion of the cis isomer from the trans was attained by a
recycling HPLC with the preparative scale GPC column
1
(over 30 times of recycling). H NMR (d, in CDCl3):
6.57 (m, 4H, m-Ph), 6.93 (t, JHH =7.8, JPH =7.8, 4H,
o-Ph), 7.14 (2H p-Ph), 7.84 (m, 2H, 2,7-naph), 7.98
(m, 2H, 3,5-naph), 8.13 (d, JHH =8.2 Hz, 2H, 4,5-naph).
13C{1H} NMR (d, in CDCl3): 127.9 (t, JPC =4.9 Hz),
128.2 (t, JPC =4.0 Hz), 130.1 (s), 130.9 (s), 131.6 (t,
JPC =7.2 Hz), 133.2 (t, JPC =6.5 Hz), 133.6 (t,
JPC =10.9 Hz), 134.8 (t, JPC =16.7 Hz), 136.9 (s), 196.6
(t, JPC =2.5 Hz, JCW =126 Hz, cis-CO), 197.7 (t,
JPC =14.0 Hz, trans-CO). 31P{1H} NMR (d, in CDCl3):
29.3 (JPW =163 Hz, JPW =94 Hz).
3.7. Synthesis of Cr(trans-1)(CO)5 (3c)
3c was prepared as described above for 3a, using
1
Cr(CO)6. IR (mCO, cmꢁ1, in THF): 2065, 1987(sh). H
NMR (d, in CDCl3): 7.15–7.35 (m, 10H, Ph), 7.50 (m,
JHH =7.3 Hz, JHH =8.4 Hz, JPH =2.6 Hz, 1H, 6-naph),
7.68 (t, JHH =7.3 Hz, JHP =7.3 Hz, 1H, 7-naph), 7.83
(m, JHH =7.1 Hz, JHH =8.4 Hz, JPH =2.9 Hz, 1H, 3-
naph), 7.91 (d, JHH =8.1 Hz, 1H, 5-naph), 8.08 (d,
JHH =8.3 Hz, 1H, 4-naph), 8.39 (m, JHH =7.1 Hz,
JHH =0.7 Hz, JPH =9.0 Hz, 1H, 2-naph). 13C{1H}
NMR (d, in CDCl3): 127.3 (d, JPC =9.4 Hz), 127.9 (d,
JPC =8.7 Hz), 128.4 (d, JPC =9.4 Hz), 128.7 (s), 128.9
(dd, JPC =1.9 Hz, JPC =8.1 Hz), 129.0 (br), 130.0 (d,
JPC =9.3 Hz), 130.2 (d, JPC =8.7 Hz), 130.6 (d,
JPC =1.9 Hz), 130.7 (d, JPC =1.9 Hz), 132.1 (dd,
JPC =3.7 Hz, JPC =26.1 Hz), 133.2 (d, JPC =6.2 Hz),
3.10. Synthesis of (OC)5Mo(l-cis-1)Mo(CO)5 (cis-2b)
and (OC)5Cr(l-cis-1)Cr(CO)5 (cis-2c)
cis-2b and cis-2c were prepared as described above for
cis-2a. Since complete separation of the cis isomer from
the trans was not successful, only 31P{1H} NMR spectra
were recorded. cis-2b: 31P{1H} NMR (d, in CDCl3):
46.5. cis-2c: 31P{1H} NMR (d, in CDCl3): 68.0.

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T. Mizuta et al. / Journal of Organometallic Chemistry 689 (2004) 2624–2632
Table 1
Crystallographic data
Trans-1
Trans-2a
Trans-3a
Cis-2a
Formula
C22H16P2
Colorless
Triclinic
C36H24O11P2W2
Yellow
C27H16O5P2W
Yellow
C32H16O10P2W2
Yellow
Crystal color
Crystal system
Space group
Monoclinic
P21/n (#14)
10.5220(1)
17.2730(2)
20.3480(2)
Monoclinic
C2/c (#15)
26.7690(3)
10.7820(1)
17.6970(3)
Monoclinic
P21/a (#14)
12.2040(1)
14.4120(2)
18.7280(2)
ꢀ
P1 (#2)
˚
a (A)
7.8660(1)
14.6310(3)
15.7980(4)
101.904(1)
93.904(1)
101.495(2)
1732.03(6)
4
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
102.173(1)
106.739(1)
73.561(1)
3
˚
V (A )
3615.03(7)
4
65.14
4891.3(1)
8
48.96
3159.31(6)
4
74.43
Z
l(Mo Ka) (cmꢁ1
)
2.50
Mo Ka
0.71069
˚
Radiation (A)
Mo Ka
0.71069
Mo Ka
0.71069
Mo Ka
0.71069
No. of reflections
Measured
7679
6734
8438
7520
5733
4914
7774
7040
Observed (I>3.00 r (I), 2h<55ꢁ)
No. variables
562
11.98
461
16.31
381
12.90
416
16.92
Reflection/parameter
p-factor
Residualsa Rb; Rw
0.1530
0.039; 0.080
0.0950
0.028; 0.052
0.1070
0.024; 0.058
0.1620
0.036; 0.086
c
P
2
a
Function minimized:
wðjF oj ꢁ jF cjÞ , where w ¼ 1=½r2ðF oÞꢂ ¼ ½r2ðF oÞ þ p2F 2=4ꢂꢁ1, rc(Fo)=e.s.d. based on counting statistics and p is the
c
o
p-factor.
b
P
P
R ¼
jj F o j ꢁ j F c jj= j F o j.
ꢂꢀ
ꢁ
ꢃꢄ
P
P
1=2
c
Rw
¼
wðj F o j ꢁ j F c j Þ2
wF 2o
.
3.11. Crystallographic study
Acknowledgement
Suitable crystals of trans-1, trans-2a, cis-2a, and
trans-3a were mounted on glass fibers. Crystallographic
data are given in Table 1. All measurements were made
on a Mac Science DIP2030 imaging plate area detector.
The data were collected to a maximum 2h value of
55.8ꢁ at ꢁ73 ꢁC. Cell parameters and intensities for
the reflection were estimated using the program packag-
es of MacDENZO [15]. The structure was solved by di-
rect methods and expanded using Fourier techniques.
Non-hydrogen atoms were refined anisotropically. Hy-
drogen atoms were included but not refined. All calcu-
lations were performed using a teXsan crystallographic
software package from the Molecular Structure
Corporation [16].
This work was supported by Grants-in-Aid for Scien-
tific Research (Nos. 15350035, 15550051, and 15036250)
from the Ministry of Education, Culture, Sports, Sci-
ence and Technology, Japan.
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