Synthesis and some reactivity of amidinato(pyridine) complexes of molybdenum and tungsten formulated as [M(η3-allyl)(amidinato)(CO) 2(NC5H5)]

Article abstract of DOI:10.1016/j.ica.2004.02.009

Bis(pyridine) complexes of molybdenum and tungsten, [M(η³- allyl)Cl(CO)₂(NC₅H₅)₂] (M=Mo; 3-Mo, M=W; 3-W), reacted with an equimolar amount of lithiated amidinate, Li[(PhN)₂CR] (R=H; 4a-Li, R = CH₃; 4b-Li), to yield corresponding amidinato(pyridine) complexes, [M(η³-allyl){(PhN) ₂CR}(CO)₂(NC₅H₅)] (M=Mo, R=H; 5a-Mo, M=Mo, R=CH₃; 5b-Mo, M=W, R=H; 5a-W), as a yellow solid. The dissociation of pyridine ligand from the central metal in complexes 5a was observed in a polar solvent such as acetonitrile. In these cases, although the formation of amidinato(acetonitrile) complexes, [M(η³-allyl) {(PhN)₂CH}(CO)₂(NCMe)] (M=Mo; 6a-Mo, M=W; 6a-W), was suggested spectroscopically, isolation of complexes 6a was not successful but the re-formation of pyridine complexes 5a was observed. In the reactions of complexes 5a with PEt₃ and with P(OMe)₃, the substitution reactions easily took place to give [M(η³-allyl){(PhN) ₂CH}(CO)₂(PEt₃)] (M=Mo; 7a-Mo, M=W; 7a-W) and [M(η³-allyl){(PhN)₂CH}(CO)₂{P(OMe) ₃}] (M=Mo; 8a-Mo, M=W; 8a-W), respectively. These complexes were characterized spectroscopically as well as, in some cases, by X-ray analyses.

Full text of DOI:10.1016/j.ica.2004.02.009

Inorganica Chimica Acta 357 (2004) 2657–2668
www.elsevier.com/locate/ica
Synthesis and some reactivity of amidinato(pyridine) complexes
of molybdenum and tungsten formulated as
[M(g3-allyl)(amidinato)(CO)2(NC5H5)]
a,
a
b
a,
*
Yoshitaka Yamaguchi *, Kenichi Ogata , Kimiko Kobayashi , Takashi Ito
a
Department of Materials Chemistry, Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku,
Yokohama 240-8501, Japan
b
The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako 351-0198, Japan
Received 24 December 2003; accepted 7 February 2004
Available online 27 February 2004
Abstract
Bis(pyridine) complexes of molybdenum and tungsten, [M(g3-allyl)Cl(CO)2(NC5H5)2] (M ¼ Mo; 3-Mo, M ¼ W; 3-W), reacted
with an equimolar amount of lithiated amidinate, Li[(PhN)2CR] (R ¼ H; 4a-Li, R ¼ CH3; 4b-Li), to yield corresponding amidi-
nato(pyridine) complexes, [M(g3-allyl){(PhN)2CR}(CO)2(NC5H5)] (M ¼ Mo, R ¼ H; 5a-Mo, M ¼ Mo, R ¼ CH3; 5b-Mo, M ¼ W,
R ¼ H; 5a-W), as a yellow solid. The dissociation of pyridine ligand from the central metal in complexes 5a was observed in a polar
solvent such as acetonitrile. In these cases, although the formation of amidinato(acetonitrile) complexes, [M(g3-al-
lyl){(PhN)2CH}(CO)2(NCMe)] (M ¼ Mo; 6a-Mo, M ¼ W; 6a-W), was suggested spectroscopically, isolation of complexes 6a was
not successful but the re-formation of pyridine complexes 5a was observed. In the reactions of complexes 5a with PEt3 and with
P(OMe)3, the substitution reactions easily took place to give [M(g3-allyl){(PhN)2CH}(CO)2(PEt3)] (M ¼ Mo; 7a-Mo, M ¼ W; 7a-
W) and [M(g3-allyl){(PhN)2CH}(CO)2{P(OMe)3}] (M ¼ Mo; 8a-Mo, M ¼ W; 8a-W), respectively. These complexes were charac-
terized spectroscopically as well as, in some cases, by X-ray analyses.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: Molybdenum complexes; Tungsten complexes; Amidinato ligand; Pyridine ligand; Substitution reaction
1. Introduction
chelating and/or a bridging ligand [4], has been known
to be one of the most important ligand for most tran-
sition metals, there has been no investigation focused on
the amidinato ligand combined with the [M(g3-allyl)-
(CO)2] (M ¼ Mo, W) fragment. Recently, we reported
the preparation of the new type of molybdenum–amid-
inato complexes, [Mo(g3-allyl)(amidinato)(CO)2L] (L ¼
amidine, phosphine) [5]. Our synthetic procedure for
amidinato complex of molybdenum involved conversion
of amidine-coordinated complex of molybdenum (1) to
amidinato one (2) induced by a base (Scheme 1). How-
ever, this method proved to be applicable only to the
synthesis of the molybdenum complexes containing a
formamidine ligand, and not for the preparation of
the analogous molybdenum–acetamidinato and tung-
sten–formamidinato complexes (Scheme 2). Further-
more, the direct reaction of bis(acetonitrile) complex
p-Allyldicarbonyl complexes of molybdenum and
tungsten
formulated
as
[M(g3-allyl)X(CO)2L2]
(M ¼ Mo, W; X ¼ halogen; L ¼ 2-electron donating
molecule) have been extensively explored [1], since
[M(g3-allyl)(CO)2] fragment often plays a role of the
key in the catalytic organic transformations [2]. From
this point of view, much effort has been made on the
synthesis and reaction of those compounds bearing
various monodentate (2-electron donor) and bidentate
(4-electron donor) ligands [3]. Although amidinato li-
gand, which acts as an anionic 4-electron donating
* Corresponding authors. Tel.: +81-453-393931; fax: +81-453-393932
(Y. Yamaguchi).
E-mail address: yyama@ynu.ac.jp (Y. Yamaguchi).
0020-1693/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2004.02.009

2658
Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
(4b-H) [6] were prepared according to the literature
Ar
N
nBuLi
methods. [W(g3-allyl)Cl(CO)2(NC5H5)2] (3-W) was
prepared from [W(g3-allyl)Cl(CO)2(NCCH3)2] [7] and
pyridine in reference to the preparation of 3-Mo.
1H, 13C{1H}, and 31P{1H} NMR spectra were re-
corded on a JEOL EX-270 spectrometer at ambient
temperature unless otherwise mentioned. 1H and
13C{1H} NMR chemical shifts were reported in ppm
relative to internal Me4Si. 31P{1H} NMR chemical
shifts were recorded in ppm relative to external H3PO4.
All coupling constants were recorded in Hz. Splitting
patterns are indicated as s, singlet; d, doublet; t, triplet;
q, quintet; m, multiplet; and br, broad signal. IR spectra
were recorded on a Perkin–Elmer 1600 FT-IR and a
HORIBA FT-730 spectrometers.
Cl
OC
OC
NHAr
H
OC
OC
Mo
ArN
Mo
ArN
H
N
N
THF
-78 ˚C→ r.t.
Ar
Ar
H
H
ArHN
ArHN
1a-Mo (Ar = Ph)
1b-Mo (Ar = p-tolyl)
2a-Mo (Ar = Ph)
2b-Mo (Ar = p-tolyl)
Scheme 1.
Ar
Base
Cl
N
OC
OC
NHAr
R
OC
OC
M
M
R
N
N
Ar
Ar
ArN
ArN
R
R
ArHN
ArHN
M = Mo, R = CH3
M = W, R = H
Ar = Ph or p-tolyl
Base = nBuLi, KH, or KOtBu
2.2. Preparation of amidinato(pyridine) complexes (5)
Scheme 2.
2.2.1. Preparation of [Mo(g3-allyl){(NC6H5)2CH}
(CO)2(NC5H5)] (5a-Mo)
[Mo(g3-allyl)Cl(CO)2(NCCH3)2] with lithiated amidi-
nate did not afford the desired complex as well.
In the course of the systematic studies to produce
amidinato complexes having [M(g3-allyl)(CO)2] frag-
ment, we found that the employment of bis(pyridine)
complex [M(g3-allyl)Cl(CO)2(NC5H5)2] (M ¼ Mo; 3-
Mo, M ¼ W; 3-W) [3b], instead of bis(acetonitrile) com-
plex, in the reaction with Li(amidinate) successfully af-
forded the amidinato(pyridine) complexes of tungsten as
well as molybdenum. In this paper, we report the synthesis
and characterization of [M(g3-allyl)(amidinato)(CO)2-
(NC5H5)] for M ¼ Mo and W. We also describe some
reactions of amidinato(pyridine) complexes with 2-elec-
tron donor molecules such as CH3CN, PEt3, and
P(OMe)3.
A solution of complex 3-Mo (295 mg, 0.76 mmol) in
THF (10 ml) was cooled to )78 °C, and then a THF
solution of 4a-Li, Li[(PhN)2CH], which was prepared by
the reaction of the parent formamidine 4a-H (150 mg,
0.67 mmol) with nBuLi (1.50 mol dmꢀ3 in a hexane
solution, 0.52 ml, 0.78 mmol) at )78 °C, was added. The
mixture was allowed to warm to room temperature.
After several hours, the volatiles were removed under
reduced pressure. The residual solid was washed with
hexane several times and then extracted with toluene.
The filtrate was evaporated off under high vacuum to
give 5a-Mo as a yellow powder (325 mg, 0.70 mmol,
yield 92%). Analytically pure 5a-Mo was obtained by
recrystallization from toluene/hexane as yellow crystals
containing 0.25 molecules of toluene solvate. IR (KBr):
1
m(CO) 1928, 1913, 1829 cmꢀ1. H NMR (toluene-d8, at
30 °C): d 1.46 (d, J ¼ 9:2 Hz, 2H, allyl-CH2), 3.52 (br,
2H, allyl-CH2), 3.70 (tt, J ¼ 9:6, 6.6 Hz, 1H, allyl-CH),
6.14 (m, 2H, m-C5H5N), 6.54 (m, 1H, p-C5H5N), 7.02
(m, 10H, C6H5), 8.26 (s, 1H, amidinato-CH), 8.34 (d,
J ¼ 4:0 Hz, 2H, o-C5H5N). (toluene-d8, at 60 °C): d 1.44
(d, J ¼ 9:6 Hz, 2H, allyl-CH2), 3.47 (d, J ¼ 6:3 Hz, 2H,
allyl-CH2), 3.70 (tt, J ¼ 9:6, 6.6 Hz, 1H, allyl-CH), 6.23
(t, J ¼ 6:6 Hz, 2H, m-C5H5N), 6.64 (t, J ¼ 7:6 Hz, 1H,
p-C5H5N), 7.00 (m, 10H, C6H5), 8.26 (s, 1H, amidinato-
CH), 8.35 (d, J ¼ 4:9 Hz, 2H, o-C5H5N). (toluene-d8, at
)60 °C): d 1.59 (d, J ¼ 9:9 Hz, 2H, allyl-CH2), 3.65 (tt,
J ¼ 9:6, 6.6 Hz, 1H, allyl-CH), 3.85 (d, J ¼ 6:6 Hz, 2H,
allyl-CH2), 5.84 (t, J ¼ 6:9 Hz, 2H, m-C5H5N), 6.15 (t,
J ¼ 7:6 Hz, 1H, p-C5H5N), 7.07 (m, 10H, C6H5), 8.44 (s,
1H, amidinato-CH), 8.45 (d, J ¼ 5:9 Hz, 2H, o-C5H5N).
13C{1H} NMR (CDCl3, at 55 °C): d 57.7 (s, allyl-CH2),
75.7 (s, allyl-CH), 118.2, 122.0, 129.4, 146.8 (s, C6H5),
124.5, 137.5, 151.2 (s, C5H5N), 156.2 (s, amidinato-CH),
227.9 (s, CO). Anal. Calc. For C23H21MoN3O2 ꢁ
2. Experimental
2.1. General procedures
All manipulations involving air- and moisture-sensi-
tive organometallic compounds were carried out under
an atmosphere of dry argon or nitrogen, which was
purified by SICAPENT (Merck Co., Inc.), by using a
standard Schlenk tube or high vacuum techniques. All
solvents were distilled over appropriate drying agents
prior to use. PEt3, P(OMe)3, Mo(CO)6, and W(CO)6
were purchased from Kanto Chemical Co., Inc., and
n
used as received. BuLi in a hexane solution was pur-
chased from Kanto Chemical Co., Inc. and titrated prior
to use. Other reagents employed in this research were
used without further purification. [Mo(g3-al-
lyl)Cl(CO)2(NC5H5)2] (3-Mo) [3b], N(C6H5)@C(H)-
N(H)C6H5 (4a-H) [6] and N(C6H5)@C(CH3)N(H)C6H5

Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
2659
0.25C7H8: C, 60.62; H, 4.73; N, 8.57. Found: C, 60.40;
H, 5.02; N, 8.75%.
(s, CO). Anal. Calc. for C23H21N3O2W ꢁ 0.25C7H8: C,
51.40; H, 4.01; N, 7.27. Found: C, 51.27; H, 4.09; N,
7.19%.
2.2.2. Preparation of [Mo(g3-allyl){(NC6H5)2CCH3}
(CO)2(NC5H5)] (5b-Mo)
2.3. Reaction of amidinato(pyridine) complexes 5a with
2-electron donor compounds
Complex 5b-Mo was prepared from complex 3-Mo
(128 mg, 0.33 mmol) and a THF solution of 4b-Li,
Li[(PhN)2CCH3], which was prepared by the reaction of
the parent acetamidine 4b-H (73 mg, 0.35 mmol) with
nBuLi (1.30 mol dmꢀ3 in a hexane solution, 0.28 ml, 0.36
mmol) at )78 °C, in the same manner as that for 5a-Mo.
5b-Mo was isolated as a yellow powder (88 mg, 0.18
mmol, yield 55%). IR (KBr): m(CO) 1926, 1829 cmꢀ1. 1H
NMR (CDCl3): d 1.24 (d, J ¼ 9:6 Hz, 2H, allyl-CH2),
1.60 (s, 3H, CH3), 2.97 (d, J ¼ 5:9 Hz, 2H, allyl-CH2),
3.41 (tt, J ¼ 9:6, 6.9 Hz, 1H, allyl-CH), 6.84–7.33 (m,
12H, m-C5H5N and C6H5), 7.76 (t, J ¼ 7:9 Hz, 1H, p-
C5H5N), 8.45 (d, J ¼ 4:6 Hz, 2H, o-C5H5N). 13C{1H}
NMR (CDCl3): d 16.5 (s, CH3), 56.8 (s, allyl-CH2), 73.0
(s, allyl-CH), 122.4, 124.1, 124.2, 128.8, 137.5, 147.5,
151.1 (s, C6H5 and C5H5N), 167.7 (s, NCN), 228.9 (s,
CO). Anal. Calc. for C24H23MoN3O2: C, 59.88; H, 4.82;
N, 8.73. Found: C, 59.77; H, 4.86; N, 8.60%.
2.3.1. Reaction of 5a with acetonitrile: reversible forma-
tion of 6a
Appropriate amount of complex 5a-Mo (ca. 10 mg)
was put into an NMR tube and then CD3CN (0.5 ml)
was added. A homogeneous yellow solution was sub-
jected to the 1H NMR measurement. This spectrum
showed the signals due to the dissociated pyridine,
which was assigned by comparison of an authentic
sample. After the NMR measurement, volatiles were
1
removed under reduced pressure. H NMR of the re-
sidual yellow solid was measured in CDCl3, thus the
spectrum showed the only signals assignable to 5a-Mo.
1H NMR of 5a-W showed the similar feature as that for
5a-Mo.
2.3.2. Reaction of 5a-Mo with triethylphosphine: prepa-
ration of 7a-Mo
To a solution of complex 5a-Mo (50 mg, 0.11 mmol) in
CH2Cl2 (5 ml) was added PEt3 (18 ll, 0.12 mmol) at room
temperature. After being stirred for 2 h, the volatiles were
removed under reduced pressure. The residual material
was recrystallized from hexane to give red crystals of 7a-
Mo [5] (30 mg, 0.059 mmol, yield 54%).
2.2.3. Preparation of [W(g3-allyl){(NC6H5)2CH}
(CO)2(NC5H5)] (5a-W)
Complex 5a-W was prepared from complex 3-W (805
mg, 1.70 mmol) and a THF solution of 4a-Li,
Li[(PhN)2CH], which was prepared by the reaction of
4a-H (335 mg, 1.71 mmol) with nBuLi (1.30 mol dmꢀ3 in
a hexane solution, 1.4 ml, 1.82 mmol) at )78 °C, in the
same manner as that for 5a-Mo. 5a-W was isolated as a
yellow powder (618 mg, 1.11 mmol, yield 65%). Ana-
lytically pure 5a-W was obtained by recrystallization
from toluene/hexane as yellow crystals containing 0.25
molecules of toluene solvate. IR (KBr): m(CO) 1919,
1905, 1816 cmꢀ1. 1H NMR (toluene-d8, at 27 °C): d 1.82
(d, J ¼ 7:3 Hz, 2H, allyl-CH2), 2.90 (tt, J ¼ 9:2, 6.6 Hz,
1H, allyl-CH), 3.44 (br, 2H, allyl-CH2), 6.10 (m, 2H, m-
C5H5N), 6.50 (t, J ¼ 7:6 Hz, 1H, p-C5H5N), 7.01 (m,
10H, C6H5), 8.35 (br, 2H, o-C5H5N), 8.89 (br, 1H,
amidinato-CH). (toluene-d8, at 70 °C): d 1.77 (d, J ¼ 8:9
Hz, 2H, allyl-CH2), 2.89 (tt, J ¼ 8:9, 6.6 Hz, 1H, allyl-
CH), 3.33 (d, J ¼ 6:3 Hz, 2H, allyl-CH2), 6.22 (t, J ¼ 7:3
Hz, 2H, m-C5H5N), 6.63 (t, J ¼ 7:6 Hz, 1H, p-C5H5N),
7.00 (m, 10H, C6H5), 8.37 (d, J ¼ 5:3 Hz, 2H, o-C5H5N),
8.88 (s, 1H, amidinato-CH). (toluene-d8, at )45 °C): d
1.99 (d, J ¼ 9:2 Hz, 2H, allyl-CH2), 2.88 (tt, J ¼ 8:9, 6.9
Hz, 1H, allyl-CH), 3.74 (d, J ¼ 6:6 Hz, 2H, allyl-CH2),
5.85 (t, J ¼ 7:3 Hz, 2H, m-C5H5N), 6.17 (t, J ¼ 7:9 Hz,
1H, p-C5H5N), 7.04 (m, 10H, C6H5), 8.42 (d, J ¼ 5:3 Hz,
2H, o-C5H5N), 9.05 (s, 1H, amidinato-CH). 13C{1H}
NMR (C6D6, at 75 °C): d 50.0 (s, allyl-CH2), 68.6 (s,
allyl-CH), 118.7, 122.9, 129.7, 146.2 (s, C6H5), 124.5,
137.1, 151.0 (s, C5H5N), 156.7 (s, amidinato-CH), 220.9
2.3.3. Reaction of 5a-W with triethylphosphine: prepara-
tion of 7a-W
Complex 7a-W was prepared from complex 5a-W (42
mg, 0.076 mmol) and PEt3 (15 ll, 0.10 mmol) in the same
manner as that for 7a-Mo. Complex 7a-W was obtained
by recrystallization from hexane as red crystals (23 mg,
0.039 mmol, yield 51%). IR (KBr): m(CO) 1912, 1820
cmꢀ1. 1H NMR (CDCl3): d 1.05 (dt, J ¼ 14:9, 7.6 Hz, 9H,
CH3), 1.81 (q, J ¼ 7:6 Hz, PCH2), 1.90 (d, J ¼ 9:9 Hz, 2H,
allyl-CH2), 2.84 (tt, J ¼ 13:2, 6.6 Hz, 1H, allyl-CH), 3.80
(dd, J ¼ 6:8, 2.2 Hz, 2H, allyl-CH2), 7.00 (d, J ¼ 7:6 Hz,
4H, C6H5), 7.25 (m, 6H, C6H5), 9.44 (d, J ¼ 4:0 Hz, 1H,
amidinato-CH). 13C{1H} NMR (CDCl3): d 7.7 (d,
J ¼ 3:7 Hz, CH3), 15.5 (d, J ¼ 23:2 Hz, PCH2), 52.9 (s,
allyl-CH2), 80.9 (d, J ¼ 6:1 Hz, allyl-CH), 117.7, 122.2,
129.3, 144.9 (s, C6H5), 151.7 (d, J ¼ 6:1 Hz, amidinato-
CH), 219.7 (d, J ¼ 11:0 Hz, CO). 31P{1H} NMR
(CH2Cl2): d 12.2 (s, with 183W satellite signals, J ¼ 223:3
Hz). Anal. Calc. for C24H31N2O2PW: C, 48.50; H, 5.26;
N, 4.71. Found: C, 48.51; H, 5.21; N, 4.67%.
2.3.4. Reaction of 5a-W with trimethylphosphite: prepa-
ration of 8a-W
To a solution of complex 5a-W (102 mg, 0.18 mmol) in
CH2Cl2 (5 ml) was added P(OMe)3 (22 ll, 0.19 mmol) at

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Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
room temperature. After being stirred for 2 h, the vola-
tiles were removed under reduced pressure. The residual
material was washed with pentane several times, ex-
tracted with hexane, and then dried in vacuo to give a red
powder of 8a-W (60 mg, 0.10 mmol, 56%). For elemental
analysis, further purification was done by recrystalliza-
2.4. Experimental procedure for X-ray crystallography
Suitable single crystals were obtained from recrys-
tallization from toluene/hexane (5a-Mo and 5a-W), or
from hexane (7a-W) and are mounted on glass fibers.
Diffraction measurements of 5a-Mo, 5a-W, and 7a-W
were made on a Rigaku AFC-7R automated four-circle
diffractometer by using graphite-monochromated Mo
tion from hot-hexane. IR (KBr): m(CO) 1921, 1828 cmꢀ1
.
1H NMR (CDCl3): d 1.96 (d, J ¼ 9:9 Hz, 2H, allyl-CH2),
2.94 (m, 1H, allyl-CH), 3.62 (d, J ¼ 10:6 Hz, 9H, OCH3),
3.82 (dd, J ¼ 7:3, 3.3 Hz, 2H, allyl-CH2), 6.92–7.33 (m,
10H, C6H5), 9.24 (d, J ¼ 4:6 Hz, 1H, amidinato-CH).
13C{1H} NMR (CDCl3): d 52.6 (d, J ¼ 5:6 Hz, POCH3),
53.9 (s, allyl-CH2), 81.1 (s, allyl-CH), 118.2, 122.0, 128.9,
145.4 (s, C6H5), 154.1 (d, J ¼ 7:8 Hz, amidinato-CH),
217.8 (d, J ¼ 13:4 Hz, CO). 31P{1H} NMR (CDCl3): d
139.3 (s, with 183W satellite signals, J ¼ 374.5 Hz). Anal.
Calc. for C21H25N2O5PW: C, 42.02; H, 4.20; N, 4.67.
Found: C, 42.27; H, 4.30; N, 4.86%.
ꢀ
Ka radiation (k ¼ 0:71069 A). The data collections were
carried out at )50 °C for 5a-Mo or at 23 °C for 5a-W
and 7a-W using the x–2h scan technique to a maximum
2h value of 60.0° for 5a-Mo, 55° for 5b-W, and 60.0° for
7a-Mo, respectively. Cell constants and an orientation
matrix for data collection were determined from 25 re-
flections with 2h angles in the range 29.82–29.98° for 5a-
Mo, 29.78–30.00° for 5a-W, and 29.82–29.98° for 7a-W,
respectively. Three standard reflections were monitored
at every 150 measurements. The data collection was
performed on a personal computer. In the reduction of
data, Lorentz and polarization corrections and an em-
pirical absorption correction (W scan) were made.
2.3.5. Reaction of 5a-Mo with trimethylphosphite: for-
mation of 8a-Mo
To a solution of molybdenum complex 5a-Mo (55
mg, 0.12 mmol) in CH2Cl2 (5 ml) was added P(OMe)3
(18 ll, 0.15 mmol) at room temperature. After being
stirred for 2.5 h, the volatiles were removed under re-
duced pressure. The residual red solid was subjected to
spectroscopic measurements. IR (KBr): m(CO) 1935,
Crystallographic data and the results of measure-
ments are summarized in Table 1. The structures were
solved by heavy-atom Patterson methods (PATTY) [8]
for 5a-Mo and 5a-W or by direct methods (SIR 92) [9]
for 7a-W, and expanded using Fourier techniques [10].
All of the non-hydrogen atoms were refined anisotrop-
ically. Except for complex 5a-Mo, all hydrogen atoms
1840 cmꢀ1 31P{1H} NMR (CDCl3): d 140.5 (s).
.
Table 1
Summary of crystal data for 5a-Mo, 5a-W, and 7a-W
1
4
1
4
5a-Mo ꢁ toluene
5a-W ꢁ toluene
C24:75H23N3O2W
578.32
7a-W
Empirical formula
Formula weight
Crystal color, habit
Crystal size (mm)
Crystal system
C24:75H23MoN3O2
490.41
C24H31N2O2PW
594.34
red, plate
yellow, prismatic
0.33 ꢂ 0.25 ꢂ 0.13
triclinic
yellow, plate
0.23 ꢂ 0.13 ꢂ 0.08
triclinic
0.38 ꢂ 0.13 ꢂ 0.08
monoclinic
P1=n (#14)
ꢁ
ꢁ
Space group
Lattice parameters
P1 (#2)
P1 (#2)
ꢀ
a (A)
13.585(3)
14.689(3)
12.733(2)
111.57(1)
103.75(2)
71.40(2)
2218.3(8)
4
13.629(4)
14.738(3)
12.852(3)
111.67(2)
103.97(2)
71.59(2)
2253(1)
4
12.217(3)
14.805(2)
13.696(2)
ꢀ
b (A)
ꢀ
c (A)
a (°)
b (°)
c (°)
100.88(1)
3
ꢀ
V (A )
2432.8(7)
4
1.623
Z value
Dcalc (g cmꢀ3
F (0 0 0)
)
1.468
1.705
1002.00
6.16
13432
1130.00
51.58
10786
1176.00
48.41
l (Mo Ka) (cmꢀ1
)
Reflections measured
Independent reflections
No. variables
7680
7081 (Rint ¼ 0:025)
12925 (Rint ¼ 0:026)
736
17.56
10349 (Rint ¼ 0:029)
568
18.22
271
26.13
Reflection/parameter ratio
Residuals: R; Rw
Residuals: R1
0.048; 0.089
0.029
0.077; 0.111
0.047
0.061; 0.105
0.036
Number of reflections to calculated R1
Goodness of fit indicator
Maximum peak in final diffraction map (e A
10220 (I > 2:0rðIÞ)
1.02
0.30
6942 (I > 2:0rðIÞ)
1.03
1.50
4738 (I > 2:0rðIÞ)
1.06
1.61
ꢀ3
ꢀ
)
ꢀ3
ꢀ
Minimum peak in final diffraction map (e A
)
)0.61
)1.56
)1.13

Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
2661
ꢀ
were located at the calculated positions (C–H 0.95 A)
and not refined. In complex 5a-Mo, the hydrogen atoms
were located from difference Fourier maps and refined
isotropically. All calculations were performed on an SGI
Indy computer using the teXsan crystallographic soft-
ware package of Molecular Structure Corporation [11].
amidinato CH proton was observed at 8.26 ppm as a
singlet. Since the observed signals are somewhat broad
at ambient temperature, the variable temperature 1H
NMR measurement for 5a-Mo was carried out. The H
NMR spectra for 5a-Mo in the region of allyl protons
are shown in Fig. 1.
1
At higher temperature (60 °C, spectrum (d) in Fig. 1),
sharp signals were observed; protons of the symmetrical
allyl ligand were observed at 1.44 (anti-CH2), 3.47 (syn-
CH2), and 3.70 (central CH proton) ppm. 13C NMR
spectrum at high temperature (55 °C) also suggested that
the complex 5a-Mo has a symmetrical geometry around
molybdenum; allyl carbons appeared at 57.7 (terminal
carbon) and 75.7 (central carbon) ppm and one signal
due to two CO carbons was observed at 227.9 ppm.
These spectral data supported that 5a-Mo possesses the
coordination geometry of isomer A shown in Scheme 4
in solution. As the temperature gradually decreased, the
doublet signal due to allyl syn-CH2 protons became
broad. Further lowering of the temperature ()60 °C,
spectrum (a) in Fig. 1) caused the signals assignable to
isomer A (allyl protons) to sharpen and a new set of
signals to appear. The new signals showed two sets of
allyl anti-CH2 protons at 1.25 and 1.45 ppm as doublet
and two sets of allyl syn-CH2 protons at 2.77 and 3.55
ppm as a broad signal. Furthermore, one signal due to
amidinato-CH proton at 7.91 ppm was also observed.
This observation of four signals due to terminal allyl
protons suggests that this compound has an asymmetric
structure around Mo. Thus, we concluded that the new
set of signals observed at lower temperature is assigned
to isomer B as depicted in Scheme 4. The formation
ratio of isomers A/B was approximately 4/1 at )60 °C.
In the case of tungsten analogue 5a-W, similar spectral
data were obtained by the variable temperature 1H
NMR measurement. The formation ratio of isomers A/
B was also ca. 4/1 at )45 °C. The twisted mechanism,
which is generally accepted for a series of p-allyldicar-
bonyl complexes of Mo and W [12], may be responsible
for this isomerization process.
3. Results and discussion
3.1. Synthesis of amidinato(pyridine) complexes, [M(g3-
allyl){(NC6H5)2CR}(CO)2(NC5H5)](M ¼ Mo, W) (5)
Bis(pyridine) complex of molybdenum, [Mo(g3-al-
lyl)Cl(CO)2(NC5H5)2] (3-Mo), was treated with
Li(formamidinate) (4a-Li), which was prepared by the
reaction of the parent amidine (4a-H) with nBuLi in situ,
in THF at )78 °C. After having been allowed to warm
to room temperature, the reaction mixture was worked
up to yield amidinato-coordinated monopyridine com-
plex of molybdenum, [Mo(g3-allyl){(NC6H5)2CH}
(CO)2(NC5H5)] (5a-Mo), which was isolated as a yellow
solid in good yield. In a similar fashion, acetamidinato
complex of Mo (5b-Mo) and formamidinato complex of
W (5a-W) were successfully prepared in moderate yield
(Scheme 3). These complexes were characterized by IR,
1H, 13C{1H} NMR, and elemental analyses. Complexes
5a-Mo and 5a-W were also characterized by a single-
crystal X-ray diffraction study (vide infra).
In IR spectrum, complex 5a-Mo showed three CO
stretching bands at 1928, 1913, and 1829 cmꢀ1, which
were slightly higher frequency than those for starting
complex 3-Mo (1910, 1818 cmꢀ1). Similar high
frequency shift was observed in complexes 5b-Mo and
5a-W. Comparing 5a-Mo with 5b-Mo, there was little
influence of the frequency on the substituent on the
central carbon of amidinato ligands (H; 5a-Mo, Me;
5b-Mo). Similar results have been obtained for amidi-
nato(phosphine) complexes of molybdenum [5]. Tung-
sten complex 5a-W showed lower CO stretching bands
(1919, 1905, and 1816 cmꢀ1) than those for molybde-
num analogue 5a-Mo. The 1H NMR spectrum of 5a-Mo
in toluene-d8 suggested the formation of the desired
amidinato(pyridine) complex (5a-Mo); three kinds of
allyl protons were observed at 1.46 (anti-CH2), 3.52
(syn-CH2), and 3.70 (central proton) ppm and form-
3.2. Reaction of amidinato(pyridine) complexes 5a with
2-electron donor molecules
3.2.1. Reaction of amidinato(pyridine) complexes 5a with
acetonitrile: spectroscopic evidence
Pyridine ligand in transition-metal complexes has
usually been known to be labile so that one can expect
its substitution with some 2-electron donor molecules
[13]. Therefore, we firstly checked the liability of pyri-
dine ligand in complexes 5a in acetonitrile, which can
generally act as 2-electron donor molecule toward
transition metals, by means of spectroscopic measure-
ments. The 1H NMR measurement of molybdenum
complex 5a-Mo in CD3CN revealed that a dissociated
pyridine molecule from molybdenum was observed in
Ph
N
Li
R
Ph
N
N
Py
Py
OC
OC
OC
OC
4-Li
Ph
M
M
N
R
N
THF
-78 ˚C → r.t.
Ph
Cl
3-Mo (M = Mo)
3-W (M = W)
4a-Li (R = H)
4b-Li (R = Me)
5a-Mo (M = Mo, R = H) 92% yield
5b-Mo (M = Mo, R = Me) 55% yield
5a-W (M = W, R = H)
65% yield
Scheme 3.

2662
Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
Fig. 1. Variable temperature 1H NMR spectra for complex 5a-Mo (in toluene-d8) in the region of allyl protons. These spectra were measured at
(a) )60 °C, (b) )30 °C, (c) 30 °C, and (d) 60 °C, respectively.
trum in CH3CN showed two CO bands (1923, 1824
cmꢀ1). From these observations, it was suggested that
Ph
N
OC
OC
OC
OC
N
M
N
H
M
the acetonitrile complexes 6a were formed by coordi-
nation of CD3CN (or CH3CN) to the metal center prior
to the coordination of pyridine ligand (Scheme 5). We
tried to isolate the acetonitrile complexes 6a from the
mixture. In both cases, isolation of 6a was unsuccessful
resulting in re-formation of pyridine complexes 5a. (As
mentioned above, synthesis of 6a-Mo by direct reaction
of bis(acetonitrile) complex [Mo(g3-allyl)Cl(CO)2-
(NCCH3)2] with lithiated amidinate was unsuccessful.
We would presume that amidinato(acetonitrile) com-
plexes 6a seem to be too unstable to be isolated.) Al-
though complexes 6a were not able to be isolated, these
N
NPh
Ph
PhN
H
isomer A
i somer B
Scheme 4.
the aromatic regions (triplet signal due to p-C5H5N at
7.73 ppm and doublet signal due to o-C5H5N at 8.56
ppm; m-C5H5N protons overlapped with phenyl protons
of amidinato ligand), whose signals were in good
agreement with an authentic sample (pyridine in
CD3CN). However, other signals being assignable to the
metal fragment were broadened and we could not obtain
further spectral information of this complex. We next
measured IR spectrum of complex 5a-Mo in CH3CN.
Two CO stretching bands were observed at 1934 and
1840 cmꢀ1, which were slightly higher frequencies than
those for pyridine complex 5a-Mo (m(CO) 1928, 1913,
1829 cmꢀ1). In a case of tungsten complex 5a-W also,
dissociation of pyridine ligand form W center in CD3CN
Ph
N
Ph
N
OC
OC
N
acetonitrile
OC
OC
M
N
H
M
H
+
N
N
Ph
evaporation
Ph
(acetonitrile)
5a-Mo (M = Mo)
5a-W (M = W)
6a-Mo (M = Mo)
6a-W (M = W)
1
was observed in the H NMR spectrum and IR spec-
Scheme 5.

Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
2663
observations suggest the promising substitution reac-
tions of 5a with some 2-electron donor substrates.
tively. The 1H NMR spectrum also showed a doublet at
9.44 ppm (J ¼ 4:0 Hz) due to formamidinato CH pro-
ton reflecting the coupling with coordinated PEt3. The
13C NMR spectrum showed a doublet signal at 219.7
3.2.2. Reaction of amidinato(pyridine) complexes 5a with
triethylphosphine
2
ppm with JPC ¼ 11:0 Hz due to the carbonyl carbons.
On treatment of complex 5a-Mo with one equivalent
of PEt3 in CH2Cl2 at room temperature, an initial yel-
low solution instantaneously changed to a red solution,
suggesting the formation of phosphine coordinated
complex 7a-Mo (Scheme 6). The product 7a-Mo was
isolated as red crystals in 54% yield, and showed the
same spectroscopic feature as the product prepared from
amidinato(amidine) complex 2a-Mo and PEt3 (Scheme
7) [5]. Isolation of complex 7a-Mo, prepared from
amidinato(pyridine) complex 5a-Mo, was found to be
much easier than that from 2a-Mo, because of easiness
of removing pyridine from reaction mixture compared
to amidine. In a case of tungsten complex 5a-W, phos-
phine complex 7a-W was also isolated in a similar
Two signals being assignable to the allyl ligand were
observed at 52.9 ppm as a singlet and at 80.9 ppm as a
doublet, and four sets of singlets due to phenyl carbons
in the amidinato ligand were observed. These results
suggest that the tertiary phosphine ligand is located in
the cis position to the CO ligands and in trans position
to the allyl ligand in solution; the feature being similar
to that of the analogous molybdenum complex 7a-Mo.
3.2.3. Reaction of amidinato(pyridine) complexes 5a with
trimethylphosphite
In respect to trivalent phosphorus compounds,
phosphite is expected to act as a greater p-acceptor li-
gand to transition metal complexes than phosphine
[13,14]. We therefore examined the reaction of amidi-
nato(pyridine) complexes 5a with trimethylphosphite
(Scheme 8). In the reaction of tungsten complex 5a-W
with one equivalent of P(OMe)3 in CH2Cl2, the solution
color changed from yellow to red as in the case for 5a
with PEt3. This observation suggested that trim-
ethylphosphite complex of tungsten (8a-W) was formed
by simple substitution reaction and the product was
successfully isolated as a red solid. In IR spectrum,
complex 8a-W showed two CO stretching bands at 1921
and 1828 cmꢀ1, which were of higher frequency than
those for triethylphosphine analogue 7a-W (1912, 1820
cmꢀ1). 31P NMR spectrum showed the singlet signal at
139.3 ppm accompanied by 183W satellite peaks with the
coupling constant of 374.5 Hz, which indicated the co-
ordination of P(OMe)3 to tungsten center. In the 13C
NMR spectrum, only one doublet due to carbonyl car-
bons was observed at 217.8 ppm with the coupling
constant of 13.4 Hz. Two singlets due to allyl carbons
were observed at 53.9 and 81.1 ppm. All these structural
features were similar to those for triethylphosphine
complexes 7a indicating that complex 8a-W has a simi-
lar geometry around tungsten atom: the P(OMe)3 ligand
is located on the cis position to the CO ligands and on
trans position to the allyl ligand in solution.
manner as a red solid in 51% yield (Scheme 6). Ele-
mental analysis, and IR spectrum, and H, 13C, and 31
1
P
NMR spectra all established the formation of complex
7a-W. The molecular structure of complex 7a-W was
determined by a single-crystal X-ray diffraction study
(vide infra).
IR spectrum of 7a-W showed two CO stretching
bands at 1912 and 1820 cmꢀ1, which were of lower
frequency than those for molybdenum analogue 7a-Mo
(1921, 1836 cmꢀ1). In 31P NMR, singlet signal was ob-
served at 12.2 ppm accompanied by satellite peaks with
a coupling constant of 223.3 Hz due to 183W of 14.4%
natural abundance, which suggests that PEt3 binds to
1
the tungsten center. In H NMR spectrum, methyl and
methylene groups in PEt3 were observed at 1.05 ppm as
double triplets and at 1.81 ppm as a quintet, respec-
Ph
N
Ph
N
OC
OC
OC
OC
PEt3
M
N
H
M
H
N
N
CH2Cl2, r.t.
Ph
Ph
Et3P
5a-Mo (M = Mo)
5a-W (M = W)
7a-Mo (M = Mo)
7a-W (M = W)
In the case of molybdenum complex, the reaction
mixture of 5a-Mo and P(OMe)3 in CH2Cl2 changed
Scheme 6.
Ph
N
Ph
N
Ph
N
Ph
N
OC
OC
OC
OC
PEt3
Mo
PhN
H
P(OMe)3
Mo
Et3P
H
OC
OC
OC
OC
M
N
H
M
H
N
N
CH2Cl2, r.t.
N
N
Ph
Ph
CH2Cl2, r.t.
Ph
Ph
(MeO)3P
H
PhHN
5a-Mo (M = Mo)
5a-W (M = W)
8a-Mo (M = Mo) not isolated
8a-W (M = W)
2a-Mo
7a-Mo
Scheme 7.
Scheme 8.

2664
Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
from yellow to red similar to the case of the tungsten
complex. After work-up, the residual red solid was
subjected to the spectroscopic measurements. The CO
stretching bands were observed at 1935 and 1840 cmꢀ1
in IR spectrum and 31P NMR spectrum showed the
singlet signal at 140.5 ppm, which is slightly lower field
than that for the tungsten complex 8a-W (139.3 ppm). A
similar tendency was observed in a series of triethyl-
phosphine complexes (13.7 ppm for Mo-7a, 12.2 ppm
for W-7a). Although these spectroscopic data indicated
the formation of the phosphite complex of Mo, 8a-Mo
was not isolated in pure form due to the decomposition
into uncharacterized materials. This decomposition
might come from the greater p-acceptability of phos-
phites.
3.3. X-ray diffraction study
3.3.1. Crystal structures of amidinato(pyridine) com-
plexes 5a-Mo and 5a-W
Fig. 3. ORTEP drawing of 5a-W (molecule a) with thermal ellipsoids
drawn at the 30% probability level. Some hydrogen atoms are omitted
for clarity.
X-ray structure analyses of complexes 5a-Mo and 5a-
W, whose crystals were obtained by recrystallization
from toluene/hexane solution, were undertaken. The
ORTEP drawings of 5a-Mo and 5a-W are displayed in
Figs. 2 and 3, respectively. The crystal data and the se-
lected bond distances and angles for 5a-Mo and 5a-W
are listed in Tables 1–3, respectively.
Both crystals contained two independent amidi-
nato(pyridine) complexes (molecules a and b) and 0.25
molecules of toluene in the lattice, which was supported
by elemental analyses. In both complexes, only molecule
A is displayed, because molecule b has a similar geom-
etry to molecule a. These complexes have pseudo octa-
hedral geometry around the central metals, and the
amidinato ligand was located on a coplanar with two
CO ligands. The pyridine ligand in these complexes is
positioned trans to g3-allyl ligand. This geometry of
amidinato(pyridine) complexes (5a) differs from that of
acetylacetonato(pyridine) complex of Mo in the solid
state, whose structure is an isomer B form depicted in
Scheme 4 [3g].
In complex 5a-Mo, two Mo-amidinato nitrogen
bond distances in a molecule are closely similar to each
other; these distances are in the range from 2.239(2) to
ꢀ
2.255(2) A. The amidinato N–C bond distances are
ꢀ
1.326(2) and 1.327(2) A in molecule a and 1.329(2) and
ꢀ
1.322(2) A in molecule b, whose distances are in good
agreement with the mean value of N–C double bond
ꢀ
ꢀ
(1.24 A) and N–C single bond (1.48 A) [4a]. The ni-
trogen atoms in amidinato ligand in both molecules
have a trigonal-planar geometry; the sum of angles
around nitrogen atom is 355.7° for N(1a), 359.6° for
N(2a), 356.1° for N(1b), and 359.8° for N(2b). These
results indicate that the amidinato N–C–N bond elec-
trons are delocalized. Tungsten analogue 5a-W is iso-
structural to the molybdenum analogue 5a-Mo and
intramolecular bond distances and angles for 5a-W are
almost similar to those for 5a-Mo.
3.3.2. Crystal structures of amidinato(phosphine) com-
plex 7a-W
The X-ray analysis of the red crystals of complex 7a-
W, grown from a hexane solution, was undertaken. The
ORTEP drawing of 7a-W is depicted in Fig. 4. The
crystal data and the selected bond distances and angles
for 7a-W are listed in Tables 1 and 4, respectively.
Fig. 2. ORTEP drawing of 5a-Mo (molecule a) with thermal ellipsoids
drawn at the 50% probability level. Some hydrogen atoms are omitted
for clarity.

Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
2665
Table 2
ꢀ
Selected bond distances (A) and angles (°) for 5a-Mo
ꢀ
Distances (A)
Angles (°)
Molecule a
Allyl
Mo(1a)–C(21a)
Mo(1a)–C(22a)
Mo(1a)–C(23a)
C(21a)–C(22a)
C(22a)–C(23a)
2.341(2)
2.214(2)
2.318(2)
1.398(3)
1.410(3)
C(21a)–C(22a)–C(23a)
116.6(2)
CO
Mo(1a)–C(14a)
Mo(1a)–C(15a)
O(1a)–C(14a)
O(2a)–C(15a)
1.956(2)
1.947(2)
1.156(3)
1.165(2)
Mo(1a)–C(14a)–O(1a)
Mo(1a)–C(15a)–O(2a)
175.7(2)
178.5(2)
Amidinato
Mo(1a)–N(1a)
Mo(1a)–N(2a)
N(1a)–C(1a)
N(2a)–C(1a)
C(1a)–H(1a)
2.239(2)
2.243(2)
1.326(2)
1.327(2)
1.01(2)
Mo(1a)–N(1a)–C(1a)
Mo(1a)–N(1a)–C(2a)
C(1a)–N(1a)–C(2a)
Mo(1a)–N(2a)–C(1a)
Mo(1a)–N(2a)–C(8a)
C(1a)–N(2a)–C(8a)
N(1a)–C(1a)–N(2a)
N(1a)–C(1a)–H(1a)
N(2a)–C(1a)–H(1a)
93.9(1)
139.6(1)
122.2(2)
93.7(1)
142.2(1)
123.7(2)
112.9(2)
124(1)
123(1)
Others
Mo(1a)–N(3a)
2.246(2)
N(1a)–Mo(1a)–N(2a)
N(1a)–Mo(1a)–N(3a)
N(2a)–Mo(1a)–N(3a)
N(1a)–Mo(1a)–C(14a)
N(1a)–Mo(1a)–C(15a)
N(2a)–Mo(1a)–C(14a)
N(2a)–Mo(1a)–C(15a)
N(3a)–Mo(1a)–C(14a)
N(3a)–Mo(1a)–C(15a)
C(14a)–Mo(1a)–C(15a)
59.13(6)
78.13(6)
79.54(6)
around M
163.98(7)
106.82(7)
113.34(7)
164.90(7)
86.69(7)
92.56(7)
78.68(8)
Molecule b
Allyl
Mo(1b)–C(21b)
Mo(1b)–C(22b)
Mo(1b)–C(23b)
C(21b)–C(22b)
C(22b)–C(23b)
2.338(2)
2.220(2)
2.326(2)
1.395(3)
1.408(3)
C(21b)–C(22b)–C(23b)
116.3(2)
CO
Mo(1b)–C(14b)
Mo(1b)–C(15b)
O(1b)–C(14b)
O(2b)–C(15b)
1.953(2)
1.949(2)
1.162(3)
1.163(3)
Mo(1b)–C(14b)–O(1b)
Mo(1b)–C(15b)–O(2b)
176.7(2)
176.8(2)
Amidinato
Mo(1b)–N(1b)
Mo(1b)–N(2b)
N(1b)–C(1b)
N(2b)–C(1b)
C(1b)–H(1b)
2.255(2)
2.246(2)
1.329(2)
1.322(2)
1.01(3)
Mo(1b)–N(1b)–C(1b)
Mo(1b)–N(1b)–C(2b)
C(1b)–N(1b)–C(2b)
Mo(1b)–N(2b)–C(1b)
Mo(1b)–N(2b)–C(8b)
C(1b)–N(2b)–C(8b)
N(1b)–C(1b)–N(2b)
N(1b)–C(1b)–H(1b)
N(2b)–C(1b)–H(1b)
93.4(1)
140.1(1)
122.6(2)
94.1(1)
142.2(1)
123.5(2)
113.3(2)
124(1)
122(1)
Others
Mo(1b)–N(3b)
2.243(2)
N(1b)–Mo(1b)–N(2b)
N(1b)–Mo(1b)–N(3b)
N(2b)–Mo(1b)–N(3b)
N(1b)–Mo(1b)–C(14b)
N(1b)–Mo(1b)–C(15b)
N(2b)–Mo(1b)–C(14b)
N(2b)–Mo(1b)–C(15b)
N(3b)–Mo(1b)–C(14b)
N(3b)–Mo(1b)–C(15b)
C(14b)–Mo(1b)–C(15b)
58.94(6)
77.31(6)
80.57(6)
164.24(7)
109.42(7)
111.34(7)
166.70(7)
89.14(7)
90.80(7)
78.39(8)
around M

2666
Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
Table 3
ꢀ
Selected bond distances (A) and angles (°) for 5a-W
ꢀ
Distances (A)
Angles (°)
Molecule a
Allyl
W(1a)–C(21a)
W(1a)–C(22a)
W(1a)–C(23a)
C(21a)–C(22a)
C(22a)–C(23a)
2.337(9)
2.207(9)
2.314(9)
1.39(1)
C(21a)–C(22a)–C(23a)
118(1)
1.42(1)
CO
W(1a)–C(14a)
W(1a)–C(15a)
O(1a)–C(14a)
O(2a)–C(15a)
1.958(9)
1.935(9)
1.17(1)
1.17(1)
W(1a)–C(14a)–O(1a)
W(1a)–C(15a)–O(2a)
176.0(8)
178.7(8)
Amidinato
W(1a)–N(1a)
W(1a)–N(2a)
N(1a)–C(1a)
N(2a)–C(1a)
2.239(6)
2.232(6)
1.32(1)
1.33(1)
W(1a)–N(1a)–C(1a)
W(1a)–N(1a)–C(2a)
C(1a)–N(1a)–C(2a)
W(1a)–N(2a)–C(1a)
W(1a)–N(2a)–C(8a)
C(1a)–N(2a)–C(8a)
N(1a)–C(1a)–N(2a)
93.7(5)
139.3(6)
123.0(7)
93.8(5)
141.8(5)
124.0(7)
113.1(7)
Others
W(1a)–N(3a)
2.227(6)
N(1a)–W(1a)–N(2a)
N(1a)–W(1a)–N(3a)
N(2a)–W(1a)–N(3a)
N(1a)–W(1a)–C(14a)
N(1a)–W(1a)–C(15a)
N(2a)–W(1a)–C(14a)
N(2a)–W(1a)–C(15a)
N(3a)–W(1a)–C(14a)
N(3a)–W(1a)–C(15a)
C(14a)–W(1a)–C(15a)
59.2(2)
77.6(2)
78.9(2)
163.3(3)
106.6(3)
112.6(3)
164.5(3)
86.6(3)
92.2(3)
79.2(4)
around M
Molecule b
Allyl
W(1b)–C(21b)
W(1b)–C(22b)
W(1b)–C(23b)
C(21b)–C(22b)
C(22b)–C(23b)
2.334(9)
2.217(8)
2.325(8)
1.41(1)
C(21b)–C(22b)–C(23b)
116.3(8)
1.41(1)
CO
W(1b)–C(14b)
W(1b)–C(15b)
O(1b)–C(14b)
O(2b)–C(15b)
1.958(8)
1.948(9)
1.15(1)
W(1b)–C(14b)–O(1b)
W(1b)–C(15b)–O(2b)
178.5(8)
177.7(8)
1.154(9)
Amidinato
W(1b)–N(1b)
W(1b)–N(2b)
N(1b)–C(1b)
N(2b)–C(1b)
2.248(6)
2.226(6)
1.32(1)
W(1b)–N(1b)–C(1b)
W(1b)–N(1b)–C(2b)
C(1b)–N(1b)–C(2b)
W(1b)–N(2b)–C(1b)
W(1b)–N(2b)–C(8b)
C(1b)–N(2b)–C(8b)
N(1b)–C(1b)–N(2b)
94.0(5)
140.4(5)
122.8(7)
94.8(5)
1.331(9)
141.4(5)
123.4(6)
112.1(7)
Others
W(1b)–N(3b)
2.233(6)
N(1b)–W(1b)–N(2b)
N(1b)–W(1b)–N(3b)
N(2b)–W(1b)–N(3b)
N(1b)–W(1b)–C(14b)
N(1b)–W(1b)–C(15b)
N(2b)–W(1b)–C(14b)
N(2b)–W(1b)–C(15b)
N(3b)–W(1b)–C(14b)
N(3b)–W(1b)–C(15b)
C(14b)–W(1b)–C(15b)
59.0(2)
76.7(2)
79.9(2)
163.7(3)
108.9(3)
111.6(3)
166.1(3)
88.8(3)
90.9(3)
78.3(4)
around M
In complex 7a-W, the amidinato ligand has a delo-
calized N–C–N skeleton: values for two W–N (amidi-
for W(1)–N(2)) and two N–C bonds in the amidinato
ꢀ
ꢀ
ligand (1.322(6) A for N(1)–C(1) and 1.326(6) A for
N(2)–C(1)) were similar to each other. Two nitrogen
ꢀ
nato) bonds (2.231(4) A for W(1)–N(1) and 2.235(4) A
ꢀ

Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
2667
ꢀ
complex 7a-Mo (2.5621(6) A) [5]. The similarities in the
bond distances and angles between molybdenum com-
plex and tungsten might have come from their similar
ꢀ
covalent radii of the central metals (Mo; 1.29 A, W; 1.30
ꢀ
A) [15]. The similar feature was observed also in com-
plexes 5a-Mo and 5a-W.
4. Summary
In a previous paper, we presented the synthesis of the
new type of amidinato complexes of molybdenum,
[Mo(g3-allyl)(amidinato)(CO)2L], where L is amidine,
via reaction of bis(amidine) complex with a base [5].
However, this synthetic method is limited to molybde-
num complexes containing formamidine. In order to
prepare straightforwardly this type of complexes of not
only molybdenum but also of tungsten, we examined the
reaction of bis(pyridine) complex with Li(amidinate).
This method successfully afforded the amidinato com-
plexes of Mo and W having one pyridine ligand. On
account of the high lability of the pyridine ligand in
these complexes, as is evidenced by their reactions with
CH3CN, PEt3, and P(OMe)3, it is expected that these
complexes may play a role of a key complex to generate
highly reactive 16-electron fragment [M(g3-allyl)(amid-
inato)(CO)2] in the solution. A further investigation of
Fig. 4. ORTEP drawing of 7a-W with thermal ellipsoids drawn at the
30% probability level. Some hydrogen atoms are omitted for clarity.
atoms adopted a trigonal-planar geometry; the sum of
angles around nitrogen is 360.0° for N(1) and 359.9° for
N(2). The W(1)–P(1) distance is 2.556(1) A, whose dis-
tance is in good agreement with that of molybdenum
ꢀ
Table 4
ꢀ
Selected bond distances (A) and angles (°) for 7a-W
ꢀ
Distances (A)
Angles (°)
Allyl
W(1)–C(22)
W(1)–C(23)
W(1)–C(24)
C(22)–C(23)
C(23)–C(24)
2.336(6)
2.214(6)
2.317(6)
1.40(1)
C(22)–C(23)–C(24)
116.5(7)
1.39(1)
CO
W(1)–C(14)
W(1)–C(15)
O(1)–C(14)
O(2)–C(15)
1.971(6)
1.958(6)
1.144(7)
1.150(7)
W(1)–C(14)–O(1)
W(1)–C(15)–O(2)
178.0(6)
178.1(6)
Amidinato
W(1)–N(1)
W(1)–N(2)
N(1)–C(1)
N(2)–C(1)
2.231(4)
2.235(4)
1.322(6)
1.326(6)
W(1)–N(1)–C(1)
W(1)–N(1)–C(2)
C(1)–N(1)–C(2)
W(1)–N(2)–C(1)
W(1)–N(2)–C(8)
C(1)–N(2)–C(8)
N(1)–C(1)–N(2)
94.8(3)
140.2(3)
125.0(4)
94.5(3)
140.6(3)
124.8(4)
111.9(4)
Others
W(1)–P(1)
2.556(1)
P(1)–W(1)–N(1)
P(1)–W(1)–N(2)
P(1)–W(1)–C(14)
P(1)–W(1)–C(15)
N(1)–W(1)–N(2)
N(1)–W(1)–C(14)
N(1)–W(1)–C(15)
N(2)–W(1)–C(14)
N(2)–W(1)–C(15)
C(14)–W(1)–C(15)
80.2(1)
83.8(1)
89.5(2)
86.2(2)
58.8(1)
164.9(2)
109.0(2)
109.4(2)
165.4(2)
81.0(3)
aound M

2668
Y. Yamaguchi et al. / Inorganica Chimica Acta 357 (2004) 2657–2668
(e) J.W. Faller, D.A. Haitko, R.D. Adams, D.F. Chodosh, J. Am.
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the reactivity of these compounds on this line is now in
progress.
(f) B.J. Brisdon, G.F. Griffin, J. Chem. Soc., Dalton Trans. (1975)
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(g) B.J. Brisdon, A.A. Woolf, J. Chem. Soc., Dalton Trans. (1978)
291;
5. Supplementary material
~
(h) M.F. Perpinan, L. Ballester, A. Santos, J. Organomet. Chem.
241 (1983) 215;
Atomic coordinates, thermal parameters, and bond
lengths and distances have been deposited at the Cam-
bridge Crystallographic Data Center. CCDC numbers:
5a-Mo: 230904; 5a-W: 230905; 7a-W: 230906.
(i) G. Barrado, D. Miguel, V. Riera, S.G. Granda, J. Organomet.
Chem. 489 (1995) 129;
ꢂ
ꢂ
(j) J. Perez, V. Riera, A. Rodriguez, S.G. Granda, Angew. Chem.
Int. Ed. 41 (2002) 1427.
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references therein;
(b) F.T. Edelmann, Coord. Chem. Rev. 137 (1994) 404.
[5] Y. Yamaguchi, K. Ogata, K. Kobayashi, T. Ito, Bull. Chem. Soc.
Jpn. 77 (2004) 303.
Acknowledgements
[6] (a) C. Lin, J.D. Protasiewicz, E.T. Smith, T. Ren, Inorg. Chem. 35
(1996) 6422;
The authors are grateful to Prof. Kohtaro Osakada
and Dr. Yasushi Nishihara (Tokyo Institute of Tech-
nology) for their kind help in the elemental analyses.
This work was partially supported by a Grant-in-Aid for
Encouragement of Young Scientists from Japan Society
for the Promotion of Science (No. 13740413), Japan and
by the DAINIPPON INK AND CHEMICALS Inc.
Award in Synthetic Organic Chemistry, Japan through
The Society of Synthetic Organic Chemistry, Japan,
granted to Y.Y.
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Bosman, R. de Gelder, R. Israel, J.M.M. Smits, Technical Report
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