Synthesis and Structure Determinations of Complexes Containing a Five-Membered Lactam Structure Based on Organohydrazido(2-) Ligands

Article abstract of DOI:10.1021/ic960778e

Acid-catalyzed reactions of the hydrazido(2-) complexes cis,mer-[WX₂(NNH₂)(PMe₂Ph)₃] (X = Cl, Br) with phthalaldehyde gave the (phthalimidin-2-yl)imido complexes cis,mer-[WX₂(NNCH₂CH₂C₆H ₄CO)(PMe₂Ph)₃], via the condensation of the terminal NH₂ group with one of the formyl groups and the following cyclization to form a phthalimidine ring. Crystal structure of the chloro complex 3a was unambiguously determined by X-ray analysis. Reaction of 3a with HBr liberated the (phthalimidin-2-yl)imido ligand as 2-aminophthalimidine in moderate yield, while treatment of 3a with KOH in THF selectively cleaved the N-N bond to give phthalimidine. A similar condensation of the hydrazido(2-) complex trans-[WF(NNH₂)(dppe)₂]⁺ (8a⁺; dppe = Ph₂PCH₂CH₂PPh₂) with phthalaldehyde resulted in the formation of the diazoalkane complex trans-[WF(NN=CHC₆H₄CHO)(dppe)₂]⁺. However, further treatment of the latter complex with AlCl₃ afforded the corresponding (phthalimidin-2-yl)imido complex trans-[WF(NNCH₂C₆H₄CO)(dppe)₂] ⁺. When 8a⁺ and its molybdenum analogue were reacted with 2,5-dimethoxy-2,5-dihydrofuran in the presence of a catalytic amount of acid, trans-[MF(NNCH=:CHCH₂CO)(dppe)₂]⁺ (11⁺; M = Mo, W) was formed as the kinetic product, which gradually isomerized to the thermodynamically more stable compound trans-[MF(NNCH₂CH=CHCO)(dppe)₂]⁺ (12⁺). Both 11⁺ and 12+ (M = W) were crystallographically characterized, and the mechanism for the isomerization of 11⁺ to 12⁺ was proposed based on the results of the ¹H NMR measurements.

Full text of DOI:10.1021/ic960778e

Inorg. Chem. 1997, 36, 161-171
161
Synthesis and Structure Determinations of Complexes Containing a Five-Membered Lactam
Structure Based on Organohydrazido(2-) Ligands1
Hidetake Seino, Youichi Ishii, and Masanobu Hidai*
Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo,
Hongo, Bunkyo-ku, Tokyo 113, Japan
ReceiVed June 27, 1996X
Acid-catalyzed reactions of the hydrazido(2-) complexes cis,mer-[WX2(NNH2)(PMe2Ph)3] (X ) Cl, Br) with
phthalaldehyde gave the (phthalimidin-2-yl)imido complexes cis,mer-[WX2(NNCH2C6H4CO)(PMe2Ph)3], via the
condensation of the terminal NH2 group with one of the formyl groups and the following cyclization to form a
phthalimidine ring. Crystal structure of the chloro complex 3a was unambiguously determined by X-ray analysis.
Reaction of 3a with HBr liberated the (phthalimidin-2-yl)imido ligand as 2-aminophthalimidine in moderate yield,
while treatment of 3a with KOH in THF selectively cleaved the N-N bond to give phthalimidine. A similar
condensation of the hydrazido(2-) complex trans-[WF(NNH2)(dppe)2]+ (8a+; dppe ) Ph2PCH2CH2PPh2) with
phthalaldehyde resulted in the formation of the diazoalkane complex trans-[WF(NNdCHC6H4CHO)(dppe)2]+.
However, further treatment of the latter complex with AlCl3 afforded the corresponding (phthalimidin-2-yl)imido
complex trans-[WF(NNCH2C6H4CO)(dppe)2]+. When 8a+ and its molybdenum analogue were reacted with 2,5-
dimethoxy-2,5-dihydrofuran in the presence of a catalytic amount of acid, trans-[MF(NNCHdCHCH2CO)(dppe)2]+
(11+; M ) Mo, W) was formed as the kinetic product, which gradually isomerized to the thermodynamically
more stable compound trans-[MF(NNCH2CHdCHCO)(dppe)2]+ (12+). Both 11+ and 12+ (M ) W) were
crystallographically characterized, and the mechanism for the isomerization of 11+ to 12+ was proposed based
1
on the results of the H NMR measurements.
Introduction
reaction with alkyl halides, acyl halides, or η6-fluorobenzene
complexes, respectively.6 Another more versatile method is
based upon the utilization of the nucleophilic reactivity of
hydrazido(2-) complexes,7,8 which can be readily obtained by
the protonation of the dinitrogen complexes of molybdenum
and tungsten.8a,9 This has led to discovery of the condensation
reaction of molybdenum or tungsten hydrazido(2-) complexes
with aldehydes or ketones to afford diazoalkane complexes.7
This reaction is applicable to a wide variety of carbonyl
compounds, and reactivities of the diazoalkane ligands thus
obtained have been extensively investigated.10 In this context,
the coordinated dinitrogen has recently been transformed into
Much effort has been involved in the development of the
chemical transformations of dinitrogen by using transition metal
complexes under mild conditions.2,3,4 Direct synthesis of
organonitrogen compounds from dinitrogen is one of the
ultimate goals in this field. Toward this goal, reactivities of
dinitrogen complexes of the type [M(N2)2(L)4] (M ) Mo, W;
L ) phosphine)5 have been widely investigated, and a series of
organonitrogen ligands have been synthesized from the coor-
dinated dinitrogen via several routes.6,7,8
One way for the C-N bond formation at the coordinated
dinitrogen is the direct alkylation, acylation, or arylation by
(6) (a) Tatsumi, T.; Hidai, M.; Uchida, Y. Inorg. Chem. 1975, 14, 2530.
(b) Chatt, J.; Diamantis, A. A.; Heath, G. A.; Hooper, N. E.; Leigh,
G. J. J. Chem. Soc., Dalton Trans. 1977, 688. (c) Ben-Shoshan, R.;
Chatt, J.; Leigh, G. J.; Hussain, W. J. Chem. Soc., Dalton Trans. 1980,
771. (d) Chatt, J.; Hussain, W.; Leigh, G. J.; Terreros, F. P. J. Chem.
Soc., Dalton Trans. 1980, 1408. (e) Busby, D. C.; George, T. A.; Iske,
S. D. A., Jr.; Wagner, S. D. Inorg. Chem. 1981, 20, 22. (f) Colquhoun,
H. M. Transition Met. Chem. 1981, 6, 57. (g) Bakar, M. A.; Hughes,
D. L.; Leigh, G. J. J. Chem. Soc., Dalton Trans. 1988, 2525. (h) Ishii,
Y.; Kawaguchi, M.; Ishino, Y.; Aoki, T.; Hidai, M. Organometallics
1994, 13, 5062.
(7) (a) Hidai, M.; Mizobe, Y.; Sato, M.; Kodama, T.; Uchida, Y. J. Am.
Chem. Soc. 1978, 100, 5740. (b) Bevan, P. C.; Chatt, J.; Hidai, M.;
Leigh, G. J. J. Organomet. Chem. 1978, 160, 165. (c) Mizobe, Y.;
Uchida, Y.; Hidai, M. Bull. Chem. Soc. Jpn. 1980, 53, 1781.
(8) (a) Chatt, J.; Heath, G. A.; Richards, R. L. J. Chem. Soc., Dalton
Trans. 1974, 2074. (b) Iwanami, K.; Mizobe, Y.; Takahashi, T.;
Kodama, T.; Uchida, Y.; Hidai, M. Bull. Chem. Soc. Jpn. 1981, 54,
1773. (c) Aoshima, T.; Mizobe, Y.; Hidai, M.; Tsuchiya, J. J.
Organomet. Chem. 1992, 423, 39.
X Abstract published in AdVance ACS Abstracts, December 15, 1996.
(1) Preparation and Properties of Molybdenum and Tungsten Dinitrogen
Complexes. 50. Part 49: Ishii, Y.; Tokunaga, S.; Seino, H.; Hidai,
M. Inorg. Chem. 1996, 35, 5118.
(2) Reviews: (a) Hidai, M.; Mizobe, Y. Chem. ReV. 1995, 95, 1115. (b)
Hidai, M.; Mizobe, Y. In Molybdenum Enzymes, Cofactors and Model
Systems; Stiefel, E. I., Coucouvanis, D., Newton, W. E., Eds.; ACS
Symposium Series 535; American Chemical Society: Washington,
DC, 1993; Chapter 22. (c) Hidai, M.; Mizobe, Y. In Reactions of
Coordinated Ligands; Braterman, P. S., Ed.; Plenum Press: New York,
1989; Vol. 2, p 53. (d) George, T. A. In Homogeneous Catalysis with
Metal Phosphine Complexes; Pignolet, L. H., Ed.; Plenum Press: New
York, 1983; Chapter 13. (e) Dilworth, J. R.; Richards, R. L. In
ComprehensiVe Organometallic Chemistry; Wilkinson, G., Stone, F.
G. A., Abel, E. W., Eds.; Pergamon Press: Oxford, U.K., 1982; Vol.
8, Chapter 60.
(3) (a) Laplaza, C. E.; Cummins, C. C. Science 1995, 268, 861. (b) Kol,
M.; Schrock, R. R.; Kempe, R.; Davis, W. M. J. Am. Chem. Soc.
1994, 116, 4382. (c) Gambarotta, S. J. Organomet. Chem. 1995, 500,
117 and references therein.
(4) Hori, M.; Mori, M. J. Org. Chem. 1995, 60, 1480 and references
therein.
(9) (a) Hidai, M.; Kodama, T.; Sato, M.; Harakawa, M.; Uchida, Y. Inorg.
Chem. 1976, 15, 2694. (b) Chatt, J.; Pearman, A. J.; Richards, R. L.
J. Chem. Soc., Dalton Trans. 1978, 1766.
(5) (a) Hidai, M.; Tominari, K.; Uchida, Y.; Misono, A. Chem. Commun.
1969, 814. (b) Ibid. 1969, 1392. (c) Bell, B.; Chatt, J.; Leigh, G. J.
Chem. Commun. 1970, 842.
(10) Reviews: (a) Mizobe, Y.; Ishii, Y.; Hidai, M. Coord. Chem. ReV.
1995, 139, 281. (b) Hidai, M.; Ishii, Y. Bull. Chem. Soc. Jpn. 1996,
69, 819.
S0020-1669(96)00778-1 CCC: $14.00 © 1997 American Chemical Society

162 Inorganic Chemistry, Vol. 36, No. 2, 1997
Seino et al.
Table 1. Selected Bond Lengths and Angles in 3a‚0.5(C6H6)
Bond Lengths (Å)
W-P(1)
2.515(3)
O-C(1)
1.21(1)
1.50(2)
1.48(1)
1.40(2)
1.40(2)
1.34(2)
1.39(2)
1.35(2)
1.41(2)
W-P(2)
2.451(3)
2.522(3)
2.530(3)
2.464(3)
1.734(9)
1.35(1)
C(1)-C(7a)
C(3)-C(3a)
C(3a)-C(4)
C(4)-C(5)
C(5)-C(6)
C(6)-C(7)
C(7)-C(7a)
C(3a)-C(7a)
W-P(3)
W-Cl(1)
W-Cl(2)
W-N(1)
N(1)-N(2)
N(2)-C(1)
N(2)-C(3)
1.40(1)
1.45(1)
Bond Angles (deg)
P(1)-W-P(2)
P(1)-W-P(3)
P(1)-W-Cl(1)
P(1)-W-Cl(2)
P(1)-W-N(1)
P(2)-W-P(3)
P(2)-W-Cl(1)
P(2)-W-Cl(2)
P(2)-W-N(1)
P(3)-W-Cl(1)
P(3)-W-Cl(2)
P(3)-W-N(1)
Cl(1)-W-Cl(2)
Cl(1)-W-N(1)
Cl(2)-W-N(1)
95.2(1)
158.5(1)
84.9(1)
80.1(1)
99.8(3)
99.6(1)
177.7(1)
88.1(1)
87.9(3)
79.7(1)
84.9(1)
96.2(3)
89.7(1)
94.4(3)
175.9(3)
W-N(1)-N(2)
179.0(8)
124(1)
129(1)
105(1)
121.1(9)
125(1)
113(1)
102.8(9)
132(1)
110(1)
117(1)
107(1)
128(1)
124(1)
O-C(1)-N(2)
O-C(1)-C(7a)
N(2)-C(1)-C(7a)
N(1)-N(2)-C(3)
N(1)-N(2)-C(1)
C(1)-N(2)-C(3)
N(2)-C(3)-C(3a)
C(3)-C(3a)-C(4)
C(3)-C(3a)-C(7a)
C(4)-C(3a)-C(7a)
C(1)-C(7a)-C(3a)
C(1)-C(7a)-C(7)
C(3a)-C(7a)-C(7)
Figure 1. ORTEP drawing for cis,mer-[WCl2(NNCH2C6H4CO)(PMe2-
Ph)3] (3a). Hydrogen atoms are omitted for clarity.
Scheme 1
almost coplanar to the phthalimidine ring. The coordination
geometry around the tungsten in the hydrazido(2-) complex
2a is completely retained in 3a, and the W-N and N-N bond
lengths and W-N-N angle are essentially similar to the
previously reported hydrazido(2-) type complexes, indicating
that the (phthalimidin-2-yl)imido ligand behaves as a six-
electron donor.
Spectroscopic data for complexes 3a-d are consistent with
the solid-state structure of 3a. The IR carbonyl stretching
frequencies are in the region of 1690-1710 cm-1, comparable
to that of free phthalimidine (1686 cm-1). The 1H NMR
resonances due to the methylene protons of the phthalimidine
rings of 3a-d appear at δ 3.5-3.9 as singlets, which are slightly
higher field shifted than that of phthalimidine (δ 4.48 in CDCl3).
The 13C NMR spectra of 3a showed signals of methylene and
carbonyl carbons at δ 45.8 and 161.3, respectively, the latter
being shifted by 11 ppm to a higher field than that of
a pyrrolylimido ligand11 by using this condensation reaction,
where 2,5-dimethoxytetrahydrofuran, a succinaldehyde equiva-
lent, was employed as the reactant. Further, the pyrrolylimido
ligand has been released from the metal as pyrrole or N-
aminopyrrole in good yield. To extend this type of reaction,
we have now investigated the reactions of the hydrazido(2-)
complexes with other dialdehydes and their equivalents. Details
of syntheses and reactivities of novel organohydrazido com-
plexes having nitrogen heterocycles will be described here.
1
phthalimidine (δ 45.8 (CH2, JCH ) 143 Hz) and 172.4 (CO)
in CDCl3). Measurements of the 1H (3a-d) and 31P{1H} (3a)
NMR spectra indicated that a pair of PMe2Ph ligands coordi-
nated to the metal in the trans position to each other are
equivalent in solution even at -80 °C. In the crystal structure
of 3a, the orientation of the phthalimidine ring nearly parallel
to the P(1)-W-P(3) axis makes the P(1) and P(3) atoms
inequivalent, but the rotation of the phthalimidin-2-yl group
around the W-N-N axis is quite facile in solution.
Results and Discussion
Synthesis and Characterization of the (Phthalimidin-2-
yl)imido Complexes. Tungsten hydrazido(2-) complexes cis,-
mer-[WX2(NNH2)(PMe2Ph)3] (2a, X ) Cl; 2b, X ) Br), readily
derived from the dinitrogen complex cis-[W(N2)2(PMe2Ph)4] (1)
by protonation with HCl or HBr,9b reacted with phthalaldehyde
in the presence of a catalytic amount of aqueous HCl or HBr to
form novel organohydrazido complexes 3a or 3b, which have
a phthalimidine ring involving the terminal nitrogen atom
(Scheme 1). The reaction proceeded smoothly at room tem-
perature, and the organohydrazido complexes 3 with substituted
(phthalimidin-2-yl)imido ligands were similarly obtained from
the corresponding phthalaldehydes in moderate yields.
According to our previous study on preparation of diazoalkane
complexes from hydrazido(2-) complexes, the condensation
with ketones required a HX catalyst, but aldehydes readily
reacted even without any additives.7 In the case of phthalal-
dehyde, the reaction with 2a provided 3a in a moderate yield
by the catalytic action of HCl, but no more than a low yield of
diazoalkane complex 4a was obtained in the absence of an acid.
Use of acetic acid as the catalyst instead of HCl resulted in the
formation of complex 4a (Scheme 2). As confirmed by these
experimental facts, the diazoalkane complex 4a is stable under
neutral or weakly acidic conditions, but rapid isomerization of
4a to 3a occurs at room temperature by addition of a strong
acid. 1H NMR measurements revealed that the methylene
protons of 3a formed by the ring closure of 4a with DCl/D2O
The representative complex 3a was fully characterized by
X-ray crystallographic analysis (Figure 1, Table 1), confirming
the presence of a phthalimidine ring including the terminal
nitrogen atom. The W-N-N bond is essentially linear and
(11) Seino, H.; Ishii, Y.; Sasagawa, T.; Hidai, M. J. Am. Chem. Soc. 1995,
117, 12181.

Lactams Based on Organohydrazido(2-) Ligands
Inorganic Chemistry, Vol. 36, No. 2, 1997 163
Scheme 2
Scheme 3
Reactivities of the (Phthalimidin-2-yl)imido Complex.
Tungsten imido or oxo complexes of the type [WX2(E)(L)3]
(X ) halogen; E ) NR, O; L ) phosphine) are known to
undergo ligand exchange reactions with various π-acceptor
ligands (L′) to give complexes of the type [WX2(E)(L)2(L′)],
in which efficient back-donation from the d2-metal center to L′
has been claimed.15 The diazoalkane and hydrazido complexes,
which have the isoelectronic structures to the imido and oxo
complexes, have recently been found to show similar reactivities
toward π-acceptor ligands.16 As expected, the (phthalimidin-
2-yl)imido complex 3a underwent ligand exchange by gentle
warming (50 °C) under 1 atm of CO to afford the CO-substituted
(phthalimidin-2-yl)imido complex 5a (Scheme 3). However,
the reaction was slower than those of diazoalkane or disilyl-
hydrazido complexes (100% conversion after 12 h at 50 °C or
at room temperature, respectively16); conversion of the starting
complex 3a was not high (90% after 48 h). In addition, the
CO stretching frequency of 5a (1991 cm-1) was much higher
than those of CO-diazoalkane or -disilylhydrazido complexes
(1940-1950 or 1931 cm-1, respectively). These facts imply a
weaker π-electron-donating ability of the (phthalimidin-2-yl)-
imido ligand with an electron-withdrawing amide-carbonyl
group.
were partially deuterated (∼0.5 H), although 3a scarcely
underwent H-D exchange even after 40 h under the same
conditions.
On the basis of these observations, the mechanism for the
phthalimidine ring formation is proposed as shown in Scheme
2. At first, the diazoalkane complex 4a is formed by the
monocondensation of 2a with phthalaldehyde with the aid of
an acid catalyst. Intramolecular nucleophilic attack of the
terminal nitrogen atom on the remaining formyl group is
promoted by a strong acid to form an intermediate (1-
hydroxyisoindolin-2-yl)imido complex, which is further con-
verted to 3a by the prototropic isomerization. When D+ is
present in the reaction system, a deuterium is introduced to the
methylene group in the last proton shift step. This mechanism
is similar to that proposed for the reaction of phthalaldehyde
with primary amine to give 2-alkylphthalimidine.12 On the other
hand, the reactions of hydrazine and monoarylhydrazines with
phthalaldehyde are known to give mostly six-membered-ring
products such as phthalazine13 and 2-aryl-1,2-dihydro-1-
hydroxyphthalazines.12a,14 Although complex 2a may be re-
garded as a metallahydrazine, only the terminal nitrogen exhibits
nucleophilicity, because the nitrogen atom directly bound to the
tungsten acts as a six-electron donor and the lone pair on the
nitrogen is donated to the metal. Therefore, only the phthali-
midine-ring formation was observed in the reaction of 2a with
phthalaldehyde.
From a view point of direct synthesis of organonitrogen
compounds from molecular nitrogen, it is important to cleave
the metal-nitrogen or nitrogen-nitrogen bond of the organo-
nitrogen ligands derived from coordinated dinitrogen.
A
previous study showed that treatment of the diazoalkane
complex [WBr2(NNdCMe2)(PMe2Ph)3] with HBr gives a
mixture of acetone azine and hydrazine through the dispropor-
tionation of acetone hydrazone initially formed from the
tungsten-nitrogen bond scission.7b Similarly, the reaction of
3a with excess HBr gave rise to the cleavage of the W-N bond,
and 2-aminophthalimidine 6 was isolated in a moderate yield
(12) (a) Grigg, R.; Gunaratne, H. Q. N.; Sridharan, V. J. Chem. Soc., Chem.
Commun. 1985, 1183. (b) Tsuruta, Y.; Kohashi, K. Anal. Chim. Acta
1987, 192, 309.
(13) (a) Boyd, G. V. In Rodd’s Chemistry of Carbon Compounds; Coffey,
S. Ed.; Elsevier Scientific Publishing Co.: Amsterdam, Netherlands,
1974; Vol. IIIE, Chapter 17. (b) Dallacker, F.; Glombitza, K. W.; Lipp,
M. Justus Liebigs Ann. Chem. 1961, 643, 82. (c) Bhattacharjee, D.;
Popp, F. D. J. Pharm. Sci. 1980, 69, 120. (d) Mallouli, A.; Lepage,
Y. Synthesis 1980, 689.
(14) (a) Thiele, J.; Falk, K. G. Justus Liebigs Ann. Chem. 1906, 347, 112.
(b) Butler, R. N.; Gillan, A. M.; McArdle, P.; Cunningham, D. J.
Chem. Soc., Chem. Commun. 1987, 1016. (c) Only 4-(nitrophenyl)-
hydrazine have been reported as an exception to form phthalimidine
ring with phthalaldehyde: Butler, R. N.; Gillan, A. M.; James, J. P.;
McArdle, P.; Cunningham, D. J. Chem. Res. Synop. 1989, 62.
(15) Reviews: (a) Wigley, D. E. In Progress in Inorganic Chemistry;
Karlin, K. D., Ed.; John Wiley & Sons, Inc.: New York, 1994; Vol.
42, p 239. (b) Nugent, W. A.; Mayer, J. M. Metal-Ligand Multiple
Bonds; Wiley Interscience: New York, 1988.
(16) (a) Aoshima, T.; Tamura, T.; Mizobe, Y.; Hidai, M. J. Organomet.
Chem. 1992, 435, 85. (b) Oshita, H.; Mizobe, Y.; Hidai, M.
Organometallics 1994, 11, 4116.

164 Inorganic Chemistry, Vol. 36, No. 2, 1997
Seino et al.
(Scheme 3). Metal species was recovered as trans-[WBr4(PMe2-
Ph)2].17 It is of great interest to note that the direct reaction
between phthalaldehyde and hydrazine does not lead to the
formation of 6 (vide supra).
Scheme 4
When 3a was reacted with KOH in methanol or ethanol, the
nitrogen-nitrogen bond cleavage proceeded to give phthalimi-
dine in 57-60% yield. The other nitrogen fragment was
liberated as ammonia (69-72%) in yields comparable to those
of the phthalimidine. Competitive cleavage of the W-N bond
also occurred in this reaction to generate 6 as a byproduct in
15-23% yield. The reaction was completed faster in methanol
(1.5 h) than in ethanol (3 h), but the selectivities of the organic
products were essentially identical. Recently we reported that
the pyrrolylimido complex [WCl2(NNCHdCHCHdCH)(PMe2-
Ph)3] also reacts with KOH under the same conditions to liberate
pyrrole and N-aminopyrrole (56% pyrrole and 37% N-aminopy-
rrole after 24 h in ethanol).11 The reactivity of 3a toward KOH
as well as its selectivity for the N-N bond cleavage is evidently
higher than that of the pyrrolylimido complex.
When 3a was treated with excess KOH and an equivalent
amount of 18-crown-6 ether in THF at room temperature, the
yields of phthalimidine and ammonia were improved to 75 and
81%, respectively. However, the reaction was slower than in
alcoholic solvents and required more than 4 h for completion
(vide supra). It is probably because of the low solubility of
KOH in THF, and the reaction scarcely occurred without the
crown ether. It is worth mentioning that no 2-aminophthali-
midine was formed under these conditions.
The reductive N-N bond cleavage promoted by KOH to
release phthalimidine from the complex is considered to be
accompanied by the oxidation of the W(IV) center to W(VI).
Although we must await further study to elucidate the N-N
bond cleavage mechanism, we consider that exchange of the
chloro ligands in 3a with hydroxide ligands promotes such a
process. Another nitrogen fragment remaining on the W(VI)
center is liberated as ammonia by further reaction with hydroxide
anions; however, no characterizable metal complexes were
obtained after the reactions in both alcohols and THF.
Phthalimidine was also obtained in 30-60% yield from
complex 3a by treatment with Na[AlH2(OCH2CH2OCH3)2] in
THF, but the yield was sensitive to the reaction time and
temperature. In conclusion, the preferential W-N or N-N bond
cleavage of 3a to liberate 2-aminophthalimidine or phthalimi-
dine, respectively, was achieved by choosing appropriate
reaction conditions.
Reaction of Hydrazido(2-) dppe Complex with Phthala-
ldehyde. Synthesis of the corresponding (phthalimidin-2-yl)-
imido derivative from a cationic hydrazido(2-) complex trans-
[WF(NNH2)(dppe)2]BF4 (8a+BF4-, dppe ) Ph2PCH2CH2PPh2)
was also investigated, the latter of which is readily obtained by
protonation of the dinitrogen complex trans-[W(N2)2(dppe)2]
(7a) with aqueous HBF4.7a In contrast to neutral hydrazido-
(2-) complexes 2, the reaction of 8a+ with phthalaldehyde in
the presence of HBF4 gave no complex containing a phthali-
midine ring, but the diazoalkane complex 9a+ in a high yield
(Scheme 4). Complex 9a+ was rather inert toward protic acids
and did not show any appreciable change after treatment with
CF3SO3H or HBF4‚OEt2 even at 68 °C. However, Lewis acids
such as aluminum chloride slowly isomerized 9a+ to the
(phthalimidin-2-yl)imido complex 10a+ in refluxing THF. The
fluorine atom on the tungsten remained intact during the
reaction, although the halogen exchange was observed in the
Friedel-Crafts reactions of the pyrrolylimido complex [MF-
(NNCHdCHCHdCH)(dppe)2]+ (M ) Mo, W) promoted by
aluminum chloride.11
Complex 10a+ showed spectroscopic properties similar to
those of 3a, except that the NMR signal of the phthalimidine
methylene protons appeared at δ 2.29, which may be due to
the shielding effect of the phenyl groups of the dppe ligands.
Similar high-field shifts have also been reported in related
diazoalkane,7a aryldiazenido,6h and pyrrolylimido11 complexes
having dppe ligands.
Two reasons may be considered for the much severer
conditions required for the isomerization of the diazoalkane
complex 9a+ to 10a+ compared with that of 4a. One is the
weaker nucleophilicity of the terminal nitrogen atom in 9a+ due
to the electron-withdrawing effect of the cationic metal center.
The other reason lies in the steric hindrance of the dppe ligands,
which makes it difficult to take adequate conformation for the
cyclization.
Reaction of Hydrazido(2-) dppe Complexes with Male-
aldehyde Equivalent. 2,5-Dimethoxy-2,5-dihydrofuran is a
cyclic acetal of malealdehyde cis-OHCCHdCHCHO, and can
be used as its synthetic equivalent. The hydrazido(2-) complex
8a+ and its molybdenum analogue 8b+ 9a readily reacted with
2,5-dimethoxy-2,5-dihydrofuran under acidic conditions to
provide two kinds of ligands having isomeric γ-lactam structures
(Scheme 5). When the reactions were stopped within short
reaction times (1 h for 8a+ and 3 h for 8b+ at room temperature),
complexes 11+ with the (2-oxo-1,3-dihydro-2H-pyrrol-1-yl)-
imido ligand were selectively obtained. On standing under
acidic conditions or by treatment with a base, complexes 11+
slowly but completely isomerized to complexes 12+ with the
(2-oxo-1,5-dihydro-2H-pyrrol-1-yl)imido ligand, where the C-C
double bond is conjugated with the amide carbonyl group.
The tungsten complexes 11a+ and 12a+ were unambiguously
characterized by the X-ray crystallographic analysis (Figures 2
and 3, Tables 2 and 3). Crystals obtained for the two salts
11a+BF4- and 12a+BF4- were isomorphic and showed closely
related structures and packing, but the C-C double bond in
each isomeric ligand was clearly distinguished. In the lactam
ring of 11a+, the C(3)-C(4) and C(4)-C(5) bonds are
recognized as a single (1.52(1) Å) and a double (1.33(1) Å)
bond, respectively, indicating that 11a+ has the 1,3-dihydro-
2H-pyrrol-2-one structure. Conversely, the bond lengths in 12a+
(C(3)-C(4), 1.333(9) Å; C(4)-C(5), 1.470(8) Å) correspond
to the 1,5-dihydro-2H-pyrrol-2-one structure. The lactam rings
of both ligands are essentially planar as expected for the ene
lactams.
(17) Moss, J. R.; Shaw, B. L. J. Chem. Soc. A 1970, 595.

Lactams Based on Organohydrazido(2-) Ligands
Inorganic Chemistry, Vol. 36, No. 2, 1997 165
Figure 3. ORTEP drawing for [WF(NNCH2CHdCHCO)(dppe)2]+
(12a+). Hydrogen atoms are omitted for clarity.
Figure 2. ORTEP drawing for [WF(NNCHdCHCH2CO)(dppe)2]+
(11a+). Hydrogen atoms are omitted for clarity.
-
Table 2. Selected Bond Lengths and Angles in 11a+BF4
Scheme 5
Bond Lengths (Å)
W-P(1)
W-P(2)
W-P(3)
W-P(4)
W-F(1)
W-N(1)
N(1)-N(2)
2.523(2)
2.524(2)
2.539(2)
2.493(2)
1.964(4)
1.746(6)
1.356(8)
N(2)-C(2)
N(2)-C(5)
O-C(2)
C(2)-C(3)
C(3)-C(4)
C(4)-C(5)
1.41(1)
1.43(1)
1.22(1)
1.51(1)
1.52(1)
1.33(1)
Bond Angles (deg)
P(1)-W-P(2)
P(1)-W-P(3)
P(1)-W-P(4)
P(1)-W-F(1)
P(1)-W-N(1)
P(2)-W-P(3)
P(2)-W-P(4)
P(2)-W-F(1)
P(2)-W-N(1)
P(3)-W-P(4)
P(3)-W-F(1)
P(3)-W-N(1)
P(4)-W-F(1)
78.36(7)
172.47(8)
99.07(8)
92.2(1)
P(4)-W-N(1)
F(1)-W-N(1)
W-N(1)-N(2)
N(1)-N(2)-C(2)
N(1)-N(2)-C(5)
C(2)-N(2)-C(5)
O-C(2)-N(2)
94.2(2)
173.4(2)
172.2(6)
125.4(8)
123.5(8)
111.0(8)
126(1)
93.0(2)
101.07(7)
171.04(7)
90.6(1)
94.5(2)
80.34(7)
80.3(1)
O-C(2)-C(3)
128(1)
N(2)-C(2)-C(3)
C(2)-C(3)-C(4)
C(3)-C(4)-C(5)
N(2)-C(5)-C(4)
105.9(9)
103.5(9)
110(1)
94.5(2)
80.8(1)
109(1)
(vide supra). The protons at the 5-position, which are located
closest to the phosphines, exhibited the largest high-field shift
(-2.4 to -2.8 ppm), and the protons at the 4-position showed
a larger shift (-0.9 to -1.2 ppm) than those at the 3-position
(-0.2 to -0.4 ppm). The greater shielding effect toward the
4-protons than the 3-protons might be interpreted in terms of
the solid-state structures of these complexes. As in Figures 2
and 3, the W-N-N bonds of 11a+ and 12a+ are slightly bent
(172-173°) toward one dppe ligand so as to reduce the
congestion between the other dppe ligand and the carbonyl
oxygen atom. As a result, the 3-position of the ring goes away
from the basal plane while the 4-position approaches the phenyl
groups of one dppe ligand.
Finally, IR spectra, which has been reported only for a
mixture of 1,3- and 1,5-dihydro-2H-pyrrol-2-ones,18a,c were
measured for both 11+ and 12+. Carbonyl absorption frequen-
cies of 12+ were ∼20 cm-1 lower than those of 11+, which is
due to the conjugation of the carbonyl group with the C-C
double bond in 12+.
The NMR data of 11a+ and 12a+ were compared with those
of free 1,3- and 1,5-dihydro-2H-pyrrol-2-ones18a,b (Tables 4 and
5). The 13C NMR chemical shifts and 13C-1H coupling
constants of the lactam parts in 11a+ and 12a+ are in good
accord with the organic counterparts, except that the chemical
shifts for the carbonyl carbons of 11a+ and 12a+ appeared by
∼10 ppm in a higher field than the reference compounds. It is
noteworthy that the long-range coupling constants of 1,3-
dihydro-2H-pyrrol-2-one were first estimated by using 11a+
(Table 5), because the low stability of free 1,3-dihydro-2H-
pyrrol-2-one prevented detailed measurements (vide infra).
1
The H signals of the lactam parts of 11+ and 12+ were
observed in a higher field region than the reference organic
counterparts, because of the shielding effect of the dppe ligands
Reaction of the neutral hydrazido(2-) complex 2a and 2,5-
dimethoxy-2,5-dihydrofuran was also attempted under acidic
or nonacidic conditions, but no characterizable compound was
obtained from the mixture.
(18) (a) Bocchi, V.; Chierici, L.; Gardini, G. P.; Mondelli, R. Tetrahedron
1970, 26, 4073. (b) Fronza, G.; Mondelli, R.; Randall, E. W.; Gardini,
G. P. J. Chem. Soc., Perkin Trans. 2 1977, 1746. (c) Baker, J. T.;
Sifniades, S. J. Org. Chem. 1979, 44, 2798.

166 Inorganic Chemistry, Vol. 36, No. 2, 1997
Seino et al.
-
Table 3. Selected Bond Lengths and Angles in 12a+BF4
the basis of this measurement, the protonation rate at the
3-position of the (2-hydroxypyrrol-1-yl)imido ligand in 13+ was
estimated to be ∼100 times faster than at the 5-position. The
half-life period of the isomerization of 11a+ under basic
conditions (17 µmol of 11a+ and PhCH2NMe2 in 0.6 mL of
solvent) was ∼3 days in CDCl3 and 36 days in CDCl3/CD3OD
(4:1). Although the isomerization in the latter solvent was much
slower than that under acidic conditions, the deuteration of the
3-position was completed within 30 min. It is noteworthy that
only monodeuteration occurred at the 5-position of 12a+. This
finding shows that the reverse reaction of 12a+ forming 13a+
or 15a did not proceed under these acidic or basic conditions.
The 2H-pyrrol-2-one structures are often observed in naturally
occurring compounds and have attracted great interest especially
as a model for the terminal ring of linear tetrapyrrolic pig-
ments.19 Although compounds of this class having substituents
on the ring carbons have been investigated widely, studies on
the chemical properties of the C-unsubstituted dihydro-2H-
pyrrol-2-one rings are limited.18 The first reliable synthesis of
1,3- and 1,5-dihydro-2H-pyrrol-2-ones was reported by Bocchi
et al. in 1970,18a and their 1-substituted derivatives were prepared
by Baker and Sifniades in 1979.18c They showed that dihydro-
2H-pyrrol-2-ones and their 1-methyl derivatives readily give
equilibrium mixtures of 1,5- and 1,3-dihydro isomers in ∼9:1
ratio, while the 1-trifluoroacetyl derivative only exists as the
1,5-dihydro form. Pure 1,3-dihydro isomers can hardly be
isolated.
Bond Lengths (Å)
W-P(1)
W-P(2)
W-P(3)
W-P(4)
W-F(1)
W-N(1)
N(1)-N(2)
2.525(2)
2.528(2)
2.538(2)
2.502(2)
1.984(3)
1.769(4)
1.346(5)
N(2)-C(2)
N(2)-C(5)
O-C(2)
C(2)-C(3)
C(3)-C(4)
C(4)-C(5)
1.400(7)
1.456(7)
1.214(7)
1.483(9)
1.333(9)
1.470(8)
Bond Angles (deg)
P(1)-W-P(2)
P(1)-W-P(3)
P(1)-W-P(4)
P(1)-W-F(1)
P(1)-W-N(1)
P(2)-W-P(3)
P(2)-W-P(4)
P(2)-W-F(1)
P(2)-W-N(1)
P(3)-W-P(4)
P(3)-W-F(1)
P(3)-W-N(1)
P(4)-W-F(1)
77.97(5)
172.02(5)
98.54(5)
91.67(9)
93.6(1)
101.85(5)
170.37(5)
90.29(9)
94.6(1)
P(4)-W-N(1)
F(1)-W-N(1)
W-N(1)-N(2)
N(1)-N(2)-C(2)
N(1)-N(2)-C(5)
C(2)-N(2)-C(5)
O-C(2)-N(2)
94.5(1)
173.4(2)
172.4(4)
124.6(5)
122.9(5)
112.3(5)
125.4(7)
130.8(7)
103.7(6)
110.6(7)
110.5(7)
102.9(6)
O-C(2)-C(3)
N(2)-C(2)-C(3)
C(2)-C(3)-C(4)
C(3)-C(4)-C(5)
N(2)-C(5)-C(4)
80.34(5)
80.35(9)
94.4(1)
80.79(9)
Scheme 6
In sharp contrast, complex 11+ containing the 1,3-dihydro-
2H-pyrrol-2-one moiety can be isolated in a pure form, stored
under ambient conditions for a long period both as crystals and
as a neutral solution, and fully characterized spectroscopically
and crystallographically in spite of its thermodynamic instability.
Obviously the stabilization of the 1,3-dihydro-2H-pyrrol-2-one
structure in 11a+ is brought about by its conjugation with the
W-N moiety and the steric effect caused by the dppe ligands.
Reactivities of the (2-Oxodihydro-2H-pyrrol-1-yl)imido
Ligands. Reactivities of free 1,3- and 1,5-dihydro-2H-pyrrol-
2-ones have been little investigated in spite of the considerable
attention to their thermodynamic and spectroscopic properties.
A few examples of conjugate additions, Diels-Alder reactions,
and 1,3-dipolar cycloadditions of some C-substituted 1,5-
dihydro-2H-pyrrol-2-ones have appeared in literature,20 while
reactivities of 1,3-dihydro-2H-pyrrol-2-ones have been rarely
reported. Therefore we have investigated the reactivities of the
dihydro-2H-pyrrol-2-one rings in complexes 11+ and 12+.
Although conjugate additions of 12+ have failed to proceed
under any condition we examined, complex 11+ showed an
interesting reactivity toward NBS.
Mechanism for the Formation of the Two Isomeric
(2-Oxodihydro-2H-pyrrol-1-yl)imido Ligands. The forma-
tion of 11+ and 12+ from 8+ is rationalized as in Scheme 5. At
first, the condensation reaction of the hydrazido(2-) ligand with
2,5-dimethoxy-2,5-dihydrofuran gives the (Z)-4-diazobut-2-enal
ligand. Similar to the formation of the (phthalimidin-2-yl)imido
ligand in 3 (vide supra), this ligand is then converted to the
(2-hydroxypyrrol-1-yl)imido ligand 13+ through the ring closure
followed by deprotonation. The ring closure proceeds under
milder conditions (at room temperature in the presence of an
acid catalyst) than that for 9a+. This is probably because the
intermediate complex 14+ for the cyclization of 9a+ has the
isoindoline type structure, which is considered to be less stable
than the intermediate complex 13+ with the pyrrole structure.
The tautomerization of 13+ gives rise to complex 11+ or 12+,
but the protonation of the (2-hydroxypyrrol-1-yl)imido ligand
is supposed to proceed much faster at the 3-position than at the
5-position and hence 11+ is initially formed. This kinetic
product 11+ slowly isomerizes to the thermodynamically more
stable product 12+ via complex 13+ by the action of an acid
catalyst (Scheme 5) or via complex 15 by a base catalyst
(Scheme 6).
When 11+ was allowed to react with 2 equiv of NBS in the
presence of Et3N and further treated with aqueous Na2S2O3 or
methanol, the (3-bromo-5-thiosulfato-2-oxo-1,5-dihydro-2H-
pyrrol-1-yl)imido complex (17) or the (3-bromo-5-methoxy-2-
oxo-1,5-dihydro-2H-pyrrol-1-yl)imido complex (18+) was iso-
lated, respectively, in good to moderate yields (Scheme 7). The
structures of 17 and 18+ were determined by 1H and 13C NMR
spectroscopy. Further, the structure of complex 18+BF4- was
unambiguously confirmed by single-crystal X-ray analysis
In order to confirm this mechanism, the isomerization of 11a+
to 12a+ was followed by means of 1H NMR. Complex
11a+BF4- was stable under neutral conditions at room temper-
ature in CDCl3/CD3OD (4:1), but when DCl/D2O or PhCH2-
NMe2 was added to the solution, rapid and complete deuteration
at the 3-position of 11a+ was first observed. Along with the
deuteration, the signals of 11a+ started to decrease slowly, and
signals due to the 4- and 5-protons of 12a+ emerged. Each
process was confirmed to be a pseudo-first-order reaction, and
under both acidic and basic conditions, the isomerization was
much slower than the deuteration: the half-life periods of the
deuteration of 11a+ and the isomerization to 12a+ under the
acidic conditions (17 µmol of 11a+ in 0.6 mL of solvent and
0.1 mL of 20% DCl/D2O) were 1.2 and 58 h, respectively. On
(19) (a) Krafft, G. A; Garcia, E. A.; Guram, A.; O’Shaughnessy, B.; Xu,
X. Tetrahedron Lett. 1986, 27, 2691. (b) Claret, J.; Farrera, J. A.;
Ribo´, J. M. Tetrahedron 1990, 46, 1039.
(20) (a) Jime´nez, M. D.; Ortega, R.; Tito, A.; Farin˜a, F. Heterocycles 1988,
27, 173. (b) Koot, W.-J.; Hiemstra, H.; Speckamp, W. N. Tetrahedron
Asymmetry 1993, 4, 1941. (c) Koot, W.-J.; Hiemstra, H.; Speckamp,
W. N. J. Org. Chem. 1992, 57, 1059. (d) Farin˜a, F.; Mart´ın, M. V.;
Paredes, M. C.; Tito, A. J. Heterocycl. Chem. 1987, 24, 1269. (e)
Cooper, D. M.; Grigg, R.; Hargreaves, S.; Kennewell, P.; Redpath, J.
Tetrahedron 1995, 51, 7791 and references therein.

Lactams Based on Organohydrazido(2-) Ligands
Inorganic Chemistry, Vol. 36, No. 2, 1997 167
Table 4. Comparison of the NMR Data for Complexes 11a+ and 12a+ with the Reference Organic Compounds
1H (δ, J in Hz)
13C (δ, J in Hz)
4-C
3-H
2.62
4-H
5-H
3.83
J45 ) 5.1
6.59
J45 ) 4.93
1.62
J45 ) 1.7
4.07
2-C
3-C
5-C
130.0b
11a+ a
4.21
J35 ) 2.0
5.19
J35 ) 2.23
6.13
J35 ) 2.0
7.30
170.1
34.5
102.3
J34 ) 2.4
1JCH ) 134
37.1
1JCH ) 182
105.1
1,3-dihydro-2H-pyrrol-2-onec
12a+ a
2.91
180.8
165.0
175.5
130.9
J34 ) 2.44
5.73
J34 ) 6.6
6.10
1JCH ) 133.0
124.0
1JCH ) 179.5
142.6
1JCH ) 185.0
52.7
1JCH ) 179
127.6
1JCH ) 178
147.6
1JCH ) 146
49.5
1,5-dihydro-2H-pyrrol-2-onec
J34 ) 5.75
J35 ) 1.95
J45 ) 1.75
1JCH ) 175.4
1JCH ) 174.2
1JCH ) 142.2
a Tetrafluoroborate in CD2Cl2 solution. b Overlapping with the signals of dppe ligands. The chemical shift was determined from the HC COSY
spectrum. c In acetone-d6 (1H, ref 18a; 13C, ref 18b).
Table 5. Long-Range C-H Coupling Constants (Hz) for Complexes 11a+ and 12a+
2J[2-C,3-H] 2J[3-C,4-H] 2J[4-C,3-H] 2J[4-C,5-H] 2J[5-C,4-H] 3J[2-C,4-H] 3J[2-C,5-H] 3J[3-C,5-H] 3J[5-C,3-H]
11a+ a
6
8
8.0
5
c
3.0
6
3
4.0
6
6
5.0
b
9
9.0
6
11
11.0
6
11
e
5
c
3.0
b
9
9.0
12a+ a
1,5-dihydro-2H-
pyrrol-2-oned
a Tetrafluoroborate in CD2Cl2 solution. b Could not be determined by the overlapping of the signals. c Broad signal. d In acetone-d6.18b e Not
assigned.
Scheme 7
Figure 4. ORTEP drawing for [WF{NNCH(OCH3)CHdCBrCO}-
(dppe)2]+ (18+). Hydrogen atoms are omitted for clarity. Intramolecular
contact of the lactam ring and one of the phenyl rings (left-beneath) of
a dppe ligand can be viewed: the dihedral angle and the closest distance
between the two rings are 6.4° and 3.3 Å.
(Figure 4, Table 6). It has been revealed that an endocyclic
double bond exists at the C(3)-C(4) position (C(3)-C(4), 1.28-
(1) Å; C(4)-C(5), 1.51(1) Å) and the C(3) and C(5) atoms
exhibit the sp2 and sp3 characters, respectively. The 5-methoxy
group and the carbonyl oxygen atom are subject to steric
interaction with the dppe ligands. The bulky former group
determines the orientation of the lactam ring, and the ring
becomes nearly parallel to the P(1)-W-P(3) axis. The
carbonyl group pushes the P(1) atom away from the basal plane
defined by the other phosphorus atoms. This effect accounts
for the large P(1)-W-N(1) angle (98.2(2)°) and the small
P(1)-W-F(1) angle (81.2(1)°) in comparison with the other
P-W-N(1) (89.2-93.0(2)°) and P-W-F(1) angles (87.5-
90.2(1)°). It should be noted that investigations of halogenated
1,3- or 1,5-dihydro-2H-pyrrol-2-ones have been very limited,
and the above bromination of 11a+ provides the first route to
the brominated 1,5-dihydro-2H-pyrrol-2-one derivatives via the
bromination of the 1,3-dihydro-2H-pyrrol-2-one ring.21
It is of much interest that the methoxy and thiosulfato groups
are bound to the hindered 5-position of the 1,5-dihydro-2H-
pyrrol-2-one ring. A possible mechanism for the formation of
17 and 18+ is as follows. First, complex 15a is formed by the
deprotonation of 11a+ with Et3N and then dibrominated at the
3- and 5-positions by NBS to give the (3,5-dibromo-2-oxo-1,5-
dihydro-2H-pyrrol-1-yl)imido complex 16+ (Scheme 7), al-
though the latter complex has not been fully characterized so
far. The bromination of 11a+ was not observed in the absence
of Et3N, suggesting that the reaction proceeds via 15a. More-
over, 12a+ did not undergo bromination even in the presence
of Et3N due to the difficulty of the deprotonation (vide supra).
The substitution for the 5-bromine atom of 16+ is considered
to be facile at room temperature, even though that the 5-position
of the lactam ligand is sterically hindered. Thus, complex 16+
liberates a bromide anion quite readily to generate a reactive
2-
dicationic intermediate 192+, which reacts with S2O3 or
methanol to give 17 or 18+, respectively. Attempts to obtain
monobrominated product(s) from the equimolar reaction of 11a+
and NBS failed, because the second bromination was rather fast
(21) Previously, 3-bromo-1,5-dihydro-5-methoxy-2H-pyrrol-2-one was pre-
pared from 3-bromo-1,5-dihydro-5-methoxy-2H-furan-2-one: Farin˜a,
F.; Mart´ın, M. V.; Paredes, M. C. Synthesis 1973, 167.

168 Inorganic Chemistry, Vol. 36, No. 2, 1997
Seino et al.
Table 6. Selected Bond Lengths and Angles in 18+BF4-‚0.5CH2Cl2
Laboratory, Department of Chemistry, Faculty of Science, The Uni-
versity of Tokyo (S, Cl, Br).
Bond Lengths (Å)
W-P(1)
W-P(2)
W-P(3)
W-P(4)
W-F(1)
W-N(1)
N(1)-N(2)
N(2)-C(2)
2.561(2)
2.522(2)
2.555(2)
2.533(2)
1.947(4)
1.728(6)
1.360(7)
1.438(9)
N(2)-C(5)
O(2)-C(2)
C(2)-C(3)
Br-C(3)
C(3)-C(4)
C(4)-C(5)
O(5)-C(5)
O(5)-C(6)
1.453(9)
1.196(9)
1.45(1)
1.874(7)
1.28(1)
1.51(1)
1.405(8)
1.428(9)
Preparation of cis,mer-[WCl2(NNCH2C6H4CO)(PMe2Ph)3]‚0.5C6H6
(3a‚0.5C6H6). To a stirred suspension of hydrazido(2-) complex 2a
(150 mg, 0.215 mmol) in THF (10 mL) were added phthalaldehyde
(34.6 mg, 0.258 mmol) and one drop of concentrated hydrochloric acid.
After stirring for 1 h at room temperature, the solvent was removed
under reduced pressure and the resultant green oil was dissolved in
benzene (3 mL). The solution was diluted with hexane (3 mL) with
stirring and filtered rapidly, and hexane (15 mL) was added to the
filtrate. Green crystals deposited were collected, washed with hexane,
and dried in vacuo (96.9 mg, 53%): 1H NMR (CDCl3) δ 1.51 (t, 6 H,
J ) 3.9 Hz, PMe), 1.81 (d, 6 H, J ) 8.7 Hz, PMe), 1.89 (t, 6 H, J )
3.9 Hz, PMe), 3.84 (s, 2 H, CH2), 7.0-7.8 (m, 19 H, aromatic); 13C
NMR (CDCl3) δ 14.6, 15.1 (PMe, t, JCP ) 14 Hz), 21.5 (PMe, d, JCP
Bond Angles (deg)
P(1)-W-P(2)
P(1)-W-P(3)
P(1)-W-P(4)
P(1)-W-F(1)
P(1)-W-N(1)
P(2)-W-P(3)
P(2)-W-P(4)
P(2)-W-F(1)
P(2)-W-N(1)
P(3)-W-P(4)
P(3)-W-F(1)
P(3)-W-N(1)
P(4)-W-F(1)
P(4)-W-N(1)
F(1)-W-N(1)
78.97(6)
168.63(7)
102.72(6)
81.2(1)
W(1)-N(1)-N(2)
N(1)-N(2)-C(2)
N(1)-N(2)-C(5)
C(2)-N(2)-C(5)
O(2)-C(2)-N(2)
O(2)-C(2)-C(3)
N(2)-C(2)-C(3)
C(2)-C(3)-C(4)
Br-C(3)-C(2)
173.6(5)
123.3(6)
122.7(6)
110.5(7)
123.8(8)
133.1(9)
103.0(7)
114.7(8)
118.7(7)
126.3(7)
108.8(7)
113.4(6)
114.9(7)
102.8(6)
115.4(6)
98.2(2)
1
) 31 Hz), 48.5 (CH2, JCH ) 148 Hz), 122-139 (aromatic), 140.4
99.42(7)
178.24(7)
89.5(1)
89.2(2)
78.82(6)
87.5(1)
93.0(2)
90.2(1)
91.0(2)
178.7(2)
(ipso-C of PPh, t, JCP ) 18 Hz), 149.3 (ipso-C of PPh, d, JCP ) 38
Hz), 161.3 (CO); 31P{1H} NMR (CDCl3) δ -17.3 (P(trans), s with
183W satellites, JPW ) 294 Hz), -14.0 (P(unique), s with 183W satellites,
JPW ) 389 Hz); IR (KBr) 1712 (sh), 1694 (ν(CdO)) cm-1. Anal. Calcd
for C35H42N2OP3Cl2W: C, 49.20; H, 4.95; N, 3.28; Cl, 8.30. Found:
C, 49.38; H, 5.27; N, 3.27; Cl, 8.71.
Br-C(3)-C(4)
C(3)-C(4)-C(5)
O(5)-C(5)-N(2)
O(5)-C(5)-C(4)
N(2)-C(5)-C(4)
C(5)-O(5)-C(6)
Preparation of cis,mer-[WBr2(NNCH2C6H4CO)(PMe2Ph)3] (3b).
A mixture of hydrazido(2-) complex 2b (150 mg, 0.190 mmol),
phthalaldehyde (38.2 mg, 0.285 mmol), and one drop of 48%
hydrobromic acid in THF (10 mL) was stirred at room temperature for
80 min. The solution was dried, and diethyl ether (2 mL) was added
to the resulting green oil. The green crystals deposited were filtered,
washed with diethyl ether (3 mL), and extracted with benzene (10 mL).
Recrystallization of the benzene extract from THF/hexane gave the title
complex (49.7 mg, 29%): 1H NMR (CDCl3) δ 1.61 (t, 6 H, J ) 3.8
Hz, PMe), 1.86 (d, 6 H, J ) 8.9 Hz, PMe), 2.05 (t, 6 H, J ) 3.8 Hz,
PMe), 3.86 (s, 2 H, CH2), 7.0-7.8 (m, 19 H, aromatic); IR (KBr) 1715
(sh), 1698 (ν(CdO)) cm-1. Anal. Calcd for C32H39N2OP3Br2W: C,
42.50; H, 4.35; N, 3.10. Found: C, 42.29; H, 4.46; N, 3.43.
even at -40 °C. Thus, major products after treatment with
Na2S2O3 were 12a+ and 17, from which 17 was isolated in 10%.
Conclusion
Hydrazido(2-) complexes, readily available from dinitrogen
complexes 1 and 7 by protonation, react with phthalaldehyde
and 2,5-dimethoxy-2,5-dihydrofuran (malealdehyde equivalent)
to form the novel organohydrazido complexes containing a five-
membered lactam ring. The condensation with phthalaldehyde
to give the (phthalimidin-2-yl)imido ligand and the subsequent
reaction with HBr or KOH lead to the preparation of 2-ami-
nophthalimidine or phthalimidine starting from coordinated
dinitrogen. This reaction exemplifies direct and fully character-
ized synthesis of a lactam from molecular nitrogen. Similar
reactions using 2,5-dimethoxy-2,5-dihydrofuran and dinitrogen
complexes 7 give the organohydrazido complexes with the 1,3-
and 1,5-dihydro-2H-pyrrol-2-one structures. The former orga-
nohydrazido complex is a kinetic product and slowly isomerized
to the latter compound.
Preparation of cis,mer-[WCl2(NNCH2C6H2Cl2CO)(PMe2Ph)3]‚-
0.5CH2Cl2 (3c‚0.5CH2Cl2). A mixture of hydrazido(2-) complex 2a
(150 mg, 0.215 mmol), 4,5-dichlorophthalaldehyde (52.4 mg, 0.285
mmol), and one drop of concentrated hydrochloric acid in THF (10
mL) was stirred at room temperature for 90 min and evaporated to
dryness. The residual green powder was washed with a small amount
of benzene and recrystallized from CH2Cl2/hexane to give hygroscopic
green plates (117 mg, 59%): 1H NMR (CDCl3) δ 1.48 (t, 6 H, J ) 3.9
Hz, PMe), 1.85 (d, 6 H, J ) 8.8 Hz, PMe), 1.91 (t, 6 H, J ) 3.9 Hz,
PMe), 3.59 (s, 2 H, CH2), 7.0-7.9 (m, 17 H, aromatic); IR (KBr) 1709
(ν(CdO)) cm-1. Anal. Calcd for C32.5H38N2OP3Cl5W: C, 42.12; H,
4.13; N, 3.02. Found: C, 42.40; H, 4.17; N, 3.20.
Experimental Section
Preparation of cis,mer-[WCl2{NNCH2C6H2(O2CH2)CO}(PMe2Ph)3]
(3d). A mixture of hydrazido(2-) complex 2a (150 mg, 0.215 mmol),
4,5-methylenedioxyphthalaldehyde (57.5 mg, 0.323 mmol), and one
drop of concentrated hydrochloric acid in THF (10 mL) was stirred at
room temperature for 1 h and evaporated to dryness. The pale green
residue was washed with diethyl ether and extracted with benzene (30
mL). The extract was concentrated to ∼0.5 mL, and the brown solution
was discarded. The residual green powdery solid was recrystallized
from CH2Cl2/hexane to give 3d as green crystals (106 mg, 57%): 1H
NMR (CDCl3) δ 1.49 (t, 6 H, J ) 3.8 Hz, PMe), 1.80 (d, 6 H, J ) 8.7
Hz, PMe), 1.88 (t, 6 H, J ) 3.8 Hz, PMe), 3.68 (s, 2 H, NCH2), 6.07
(s, 2 H, OCH2O), 6.51 (s, 1 H, aromatic), 7.0-7.6 (m, 16 H, aromatic);
IR (KBr) 1690 (ν(CdO)) cm-1. Anal. Calcd for C33H39N2O3P3Cl2W:
C, 46.12; H, 4.57; N, 3.26. Found: C, 46.28; H, 4.76; N, 3.22.
General Information. All reactions were carried out under a dry
nitrogen atmosphere. Solvents were dried by the usual methods and
distilled before use. 4,5-Dichloro- and 4,5-methylenedioxyphthalal-
dehydes were prepared by the oxidation of the corresponding phthalyl
alcohols using NBS22 and MnO2,13c respectively. Other reagents were
commercially obtained and used as received. Dinitrogen complexes
1, 7a,b23 and hydrazido(2-) complexes 2a,b9b and 8a,b+
were
7a,9a
prepared according to the literature methods. NMR spectra were
recorded on a JEOL JNM-EX-270 spectrometer (1H 270 MHz, 13C 67.9
MHz, 31P 109 MHz), and IR spectra were recorded on a Shimadzu
FTIR-8100M spectrophotometer. Amounts of the solvent molecules
in the crystals were determined not only by elemental analyses but
1
also by H NMR spectroscopy. Direct bonding and long-range 13C-
1H coupling constants were measured using 1H-gated decoupling method
and assigned according to the HC COSY and the selective 1H-decoupled
spectra. Elemental analyses were performed on a Perkin-Elmer 2400
series II CHN analyzer (C, H, N) or at The Elemental Analysis
Reaction of 2a and Phthalaldehyde Catalyzed by Acetic Acid.
Phthalaldehyde (72.8 mg, 0.543 mmol) and acetic acid (12 µL, 0.21
mmol) were added to a suspension of hydrazido(2-) complex 2a (152
mg, 0.217 mmol) in THF (10 mL). The mixture was stirred at room
temperature for 21 h, and the homogeneous brown solution was dried.
Addition of diethyl ether (20 mL) to the resulting oil gave a yellow-
brown powder and a brown solution, and the latter was concentrated
to half of its original volume. The liquid phase containing the excess
(22) Blair, J.; Logan, W. R.; Newbold, G. T. J. Chem. Soc. 1956, 2443.
(23) Hussain, W.; Leigh, G. J.; Ali, H. M.; Pickett, C. J.; Rankin, D. A. J.
Chem. Soc., Dalton Trans. 1984, 1703.

Lactams Based on Organohydrazido(2-) Ligands
Inorganic Chemistry, Vol. 36, No. 2, 1997 169
phthalaldehyde was discarded. The residual powder was extracted with
diethyl ether (30 mL), and the extract was evaporated to dryness.
Recrystallization from C6H6/hexane gave brown crystals of 4a (92 mg,
52%): 1H NMR (CDCl3) δ 1.45 (d, 6 H, J ) 8.4 Hz, PMe), 1.71, 1.95
(t, 6 H each, J ) 3.9 Hz, PMe), 7.0-7.8 (m, 19 H, aromatic), 8.44 (s,
1 H, NN)CH), 9.95 (s, 1 H, CHO); IR (KBr) 1688 (ν(CdO)), 1530
(ν(N)C)) cm-1. Anal. Calcd for C32H39N2OP3Cl2W: C, 47.14; H,
4.82; N, 3.44. Found: C, 47.40; H, 4.91; N, 3.36.
Reaction of 4a with DCl. To a CDCl3 (0.6 mL) solution of 4a (10
mg) was added 20% DCl /D2O (1 drop), and the mixture was shaken
for 1 min. During this period, the color of the solution changed from
brown to green. 1H NMR measurement confirmed the quantitative
formation of 3a, while the integrated intensity of the signal due to the
phthalimidine CH2 protons was estimated as 1.5 H.
and the resulting solution was used for the determination of ammonia
(indophenol method).25
2. In THF. To a solution of 3a‚0.5C6H6 (100 mg, 0.117 mmol) in
THF (3 mL) was added KOH (∼50 mg, 0.89 mmol) and 18-crown-6
ether (∼31 mg, 0.12 mmol), and the mixture was stirred at room
temperature for 6 h. The brownish yellow solution and white solid
formed were analyzed by the methods described above.
Preparation of trans-[WF(NNdCHC6H4CHO)(dppe)2][BF4]‚-
0.5CH2Cl2 (9a+BF4-‚0.5CH2Cl2). To a CH2Cl2 (10 mL) suspension
of hydrazido(2-) complex 8a+BF4-‚CH2Cl2 (1.00 g, 0.832 mmol) and
phthalaldehyde (1.12 g, 8.32 mmol) was added 42% aqueous HBF4 (2
drops). After the mixture was stirred for 19 h, the light green solution
was dried over MgSO4 and filtered through Celite. The solvent was
removed by a rotary evaporator, and the resultant sticky oil was washed
repeatedly with diethyl ether. The green oil was recrystallized twice
from CH2Cl2/diethyl ether to give green crystals (951 mg, 90%): 1H
NMR (CDCl3) δ 2.6-3.1 (m, 8 H, CH2 of dppe), 6.9-7.4 (m, 41 H,
Ph of dppe and NN)CH at δ 7.14 (confirmed by HC COSY)), 7.5-
7.8 (m, 4 H, C6H4), 9.55 (s, 1 H, CHO); 13C{1H} NMR (CDCl3) δ
31.7 (CH2 of dppe, quint, JCP ) 10 Hz), 126-135 (aromatic), 162.0
Reaction of 3a with CO. A THF solution (15 mL) of 3a‚0.5C6H6
(610 mg, 0.714 mmol) was stirred under 1 atm of CO at 50 °C for 48
h. The 1H NMR spectrum of the crude mixture indicated that it
contained 3a and the carbonyl complex cis,trans-[WCl2(NNCH2-
C6H4CO)(PMe2Ph)2(CO)] (5a) in ∼1:9 ratio. A small amount of a
green precipitate was filtered off, and the filtrate was evaporated to
dryness. Addition of diethyl ether to the resultant brown oil formed a
brownish purple crystalline solid, which was collected by filtration and
washed with diethyl ether. The solid was extracted with benzene (10
mL), and the extract was concentrated to ∼3 mL. Addition of hexane
(15 mL) deposited brown crystals of 5a (273 mg, 54%): 1H NMR
(CDCl3) δ 1.98, 2.12 (t, 6 H each, J ) 4.1 Hz, PMe), 3.45 (s, 2 H,
CH2), 7.0-7.7 (m, 14 H, aromatic); IR (KBr) 1991 (ν(CtO)), 1711
(NN)CH), 191.7 (CHO); 31P{1H} NMR (CDCl3) δ 31.3 (d with 183
W
satellites, JPF ) 40, JPW ) 286 Hz); IR (KBr) 1690 (ν(CdO)), 1532
(ν(C)N)) cm-1. Anal. Calcd for C60.5H55N2OBF5P4ClW: C, 56.99;
H, 4.35; N, 2.20. Found: C, 57.03; H, 4.38; N, 2.21.
Preparation of trans-[WF(NNCH2C6H4CO)(dppe)2][BF4] (10a+B-
F4-). A solution of 9a+BF4-‚0.5CH2Cl2 (1.00 g, 0.785 mmol) and
AlCl3 (104.5 mg, 0.785 mmol) in THF (40 mL) was refluxed for 48 h.
The brown opaque mixture was diluted with CH2Cl2 (50 mL), washed
successively with 5% aqueous NH4BF4 (4 × 100 mL), and dried over
MgSO4. The solvent was evaporated, and the resultant orange-brown
oil was recrystallized from CH2Cl2-methanol/diethyl ether to give
orange-brown crystals (370 mg, 38%). An analytical sample was
obtained by further recrystallization from CH2Cl2/hexane: 1H NMR
(CDCl3) δ 2.29 (s, 2 H, CH2), 2.6-2.8, 3.3-3.5 (m, 4 H each, CH2 of
dppe), 6.8-7.6 (m, 44 H, aromatic); 13C NMR (CD2Cl2) δ 32.9 (CH2
(ν(CdO)) cm-1 31P{1H} NMR (CDCl3) δ -11.3 (s with 183W satellites,
;
JPW ) 286 Hz). Anal. Calcd for C25H28N2O2P2Cl2W: C, 42.58; H,
4.00; N, 3.97. Found: C, 42.61; H, 4.15; N, 4.06.
Reaction of 3a with HBr. Hydrogen bromide gas was bubbled
through a solution of 3a‚0.5C6H6 (200 mg, 0.234 mmol) in CH2Cl2
(15 mL) at 0 °C for 5 min. The red solution formed was stirred at 0
°C for 16 h and then at room temperature for 8 h. The solvent was
removed under reduced pressure, and methanol (5 mL) was added to
the residue. Red crystals of [WBr4(PMe2Ph)2] were filtered, washed
with methanol (6 mL), and dried in vacuo (113 mg, 62%). The
combined methanol solution was evaporated to dryness, and the green
oily residue was extracted with water (10 mL) and 1% hydrobromic
acid (2 × 10 mL). The extracts were combined, alkalified with KOH
(∼200 mg), and extracted with CH2Cl2 (3 × 10 mL). After being dried
over MgSO4, the solution was evaporated to dryness under reduced
pressure, and the resultant yellow solid was extracted with hot hexane
(3 × 10 mL). Recrystallization of the hexane extract from benzene-
hexane gave colorless crystals of 2-aminophthalimidine 6 (15.1 mg,
44%): 1H NMR (CDCl3) δ 4.36 (br s, 2 H, NH2), 4.52 (s, 2 H, CH2),
7.4-7.9 (m, 4 H, aromatic); 13C NMR (CDCl3) δ 53.0 (CH2), 122.7,
123.5, 128.1, 131.4, 131.5, 139.5 (aromatic), 167.7 (CO); IR (KBr)
3293, 3270 (ν(NsH)), 1705 (ν(CdO)) cm-1; mp 89-90 °C (lit.24 mp
96 °C). Selected data for [WBr4(PMe2Ph)2]: 1H NMR (CDCl3) δ
-27.56 (br s, 12 H, PMe), 8.16 (t, 2 H, J ) 7 Hz, p-H), 9.02 (t, 4 H,
J ) 7 Hz, m-H), 12.11 (d, 4 H, J ) 7 Hz, o-H). Anal. Calcd for
C16H22P2Br4W: C, 24.65; H, 2.84; Br, 40.99. Found: C, 24.97; H,
2.81; Br, 40.16.
Reaction of 3a with KOH. 1. In alcoholic solvents. A mixture
of 3a‚0.5C6H6 (100 mg, 0.117 mmol) and KOH (∼50 mg, 0.89 mmol)
in methanol or ethanol (3 mL) was stirred at room temperature. The
reaction mixture in methanol changed to slightly turbid orange after
1.5 h, while the ethanol solution became pale yellow and deposited a
white solid after 3 h. Phthalimidine thus formed was identified by
GC-MS and determined by GLC after neutralization of the reaction
mixture with acetic acid (60 µL, 1.05 mmol). The solvent was removed
under reduced pressure, and the CDCl3 extract of the residue was
analyzed by NMR. Phthalimidine, 6, and PMe2Ph were confirmed,
and the amount of 6 was estimated based on the GLC yield of
phthalimidine and the integration values of the NMR signals. On the
other hand, volatile components of the reaction mixture before
neutralization were trapped in aqueous H2SO4 under reduce pressure,
1
of dppe, quint, JCP ) 9 Hz), 50.3 (NCH2, JCH ) 147 Hz), 122-139
(aromatic), 162.9 (CO); 31P{1H} NMR (CDCl3) δ 30.8 (d with 183W
satellites, JPF ) 43, JPW ) 286 Hz); IR (KBr) 1701 (ν(CdO)) cm-1
.
Anal. Calcd for C60H54N2OBF5P4W: C, 58.46; H, 4.42; N, 2.27.
Found: C, 57.77; H, 4.44; N, 2.32.
Preparation of trans-[WF(NNCH)CHCH2CO)(dppe)2][BF4]
(11a+BF4-). To a solution of hydrazido(2-) complex 8a+BF4-‚CH2Cl2
(200 mg, 0.166 mmol) in CH2Cl2 (10 mL) were added 2,5-dimethoxy-
2,5-dihydrofuran (24 µL, 0.20 mmol) and 42% aqueous HBF4 (1 drop).
After stirring for 1 h, the reddish brown solution was dried over MgSO4,
filtered through Celite, and evaporated. The resulting dark-brown oil
was fractionated by gel chromatography (Sephadex LH-20; eluent,
methanol/CH2Cl2 (4:1)). The orange band was collected and recrystal-
lized from CH2Cl2-methanol/diethyl ether. The title complex was
crystallized in two different crystal forms: an orange-red columnar
crystal (61.7 mg, 31%), and the other dark-red prismatic and efflorescent
(92.8 mg, 46%; contained 0.5 molecule of diethyl ether after vacuum
drying). The former crystals were used for X-ray and elemental
analyses: 1H NMR (CDCl3) δ 2.53 (br t, 2 H, J ) 2.2 Hz, COCH2),
2.6-2.8, 3.1-3.3 (m, 4 H each, CH2 of dppe), 4.06 (dt, 1 H, J ) 5.0,
2.2 Hz, NCH), 4.30 (dt, 1 H, J ) 5.0, 2.5 Hz, NCH)CH), 6.9-7.4
(m, 40 H, Ph of dppe); 13C{1H} NMR (CD2Cl2) δ 32.8 (CH2 of dppe,
quint, JCP ) 10 Hz), 34.5 (COCH2), 102.3 (NCH)CH), 128-134 (Ph
of dppe and NCH (δ 130.0)), 170.1 (CO); 31P{1H} NMR (CDCl3) δ
30.9 (d with 183W satellites, JPF ) 43, JPW ) 285 Hz); IR (KBr) 1705
(ν(CdO)), 1609 (ν(CdC)) cm-1
.
Anal. Calcd for C56H52N2-
OBF5P4W: C, 56.88; H, 4.43; N, 2.37. Found: C, 56.25; H, 4.37; N,
2.44.
Its molybdenum analogue trans-[MoF(NNCHdCHCH2CO)-
(dppe)2][BF4] (11b+BF4-) was prepared similarly from 8b+BF4- in 63%
yield, but the reaction required a longer time (3 h). Reddish purple
crystals from CH2Cl2/hexane: 1H NMR (CDCl3) δ 2.50 (br s, 2 H,
COCH2), 2.6-2.8, 3.1-3.3 (m, 4 H each, CH2 of dppe), 4.35-4.45
(24) Anderson, D. J.; Horwell, D. C.; Stanton, E.; Gilchrist, T. L.; Rees,
(25) Takahashi, T.; Mizobe, Y.; Sato, M.; Uchida, Y.; Hidai, M. J. Am.
Chem. Soc. 1980, 102, 7461.
C. W. J. Chem. Soc., Perkin Trans. 1 1972, 1317.

170 Inorganic Chemistry, Vol. 36, No. 2, 1997
Seino et al.
Table 7. Crystallographic Data for 3a‚0.5C6H6, 11a+BF4-, 12a+BF4-, and 18+BF4-‚0.5CH2Cl2
-
-
3a‚0.5C6H6
11a+BF4
12a+BF4
18+BF4-‚0.5CH2Cl2
formula
formula weight
space group
a (Å)
b (Å)
c (Å)
C35H42N2OP3Cl2W
854.41
C56H52N2OBF5P4W
1182.59
C56H52N2OBF5P4W
1182.59
C57.5H54N2O2BF5P4ClBrW
1333.98
C2/c (No.15)
37.952(4)
18.382(3)
10.368(2)
93.97(2)
7215(1)
P21/n (No.14)
17.712(4)
17.933(5)
17.715(3)
110.16(2)
5282(2)
P21/n (No.14)
17.710(2)
17.885(2)
17.785(2)
110.278(8)
5283.9(9)
4
1.486
1.487 (25 °C)
24.08
P21/n (No.14)
12.798(2)
27.619(2)
17.002(2)
109.79(1)
5655(1)
â (deg)
V (Å3)
Z
8
4
4
F
calc (g cm-3
obsd (g cm-3
calc (cm-1
)
)
1.573
1.548 (17 °C)
35.16
0.6396-0.9985
0.054
1.487
1.488 (24 °C)
24.08
0.7131-0.9996
0.048
1.567
1.589 (17 °C)
29.74
0.6613-1.0000
0.049
F
µ
)
transmn factor
0.9283-0.9986
0.039
0.022
Ra
b
Rw
0.046
0.026
0.033
2
a R ) ∑||Fo| - |Fc||/∑|Fo|. b Rw ) [∑w(|Fo| - |Fc|)2/∑wFo ]1 / 2
.
(m, 2 H, CH)CH), 6.9-7.4 (m, 40 H, Ph of dppe); IR (KBr) 1713
(ν(CdO)), 1609 (ν(CdC)) cm-1. Anal. Calcd for C56H52N2OBF5P4-
Mo: C, 61.44; H, 4.79; N, 2.56. Found: C, 61.25; H, 4.84; N, 2.69.
mmol) and Et3N (12 µL, 0.086 mmol) at -40 °C. After stirring at the
same temperature for 4 h, the resulting orange solution was slowly
warmed to room temperature and quenched with 5% aqueous Na2S2O3
(5 mL). The mixture was immediately diluted with CH2Cl2 (20 mL)
and washed successively with 5% aqueous Na2S2O3 (2 × 50 mL) and
5% aqueous NH4BF4 (4 × 50 mL). The organic layer was dried over
MgSO4 and evaporated to leave an orange-red oil, which was
crystallized from CH2Cl2-methanol/diethyl ether to give 17‚0.5(diethyl
ether) as red crystals (81.6 mg, 73%): 1H NMR (CDCl3) δ 2.6-2.8,
3.3-3.5 (m, 4 H each, CH2 of dppe), 5.50 (d, 1 H, J ) 2.2 Hz, NCH),
7.0-7.4 (m, 41 H, Ph of dppe and NCH(SSO3)CH at δ 7.21 (confirmed
by HH COSY)); 13C NMR (CD2Cl2) δ 31-32.5 (CH2 of dppe), 66.5
Preparation of trans-[WF(NNCH2CHdCHCO)(dppe)2][BF4]
(12a+BF4-). A CH2Cl2 (5 mL) solution of 11a+BF4- (200 mg, 0.169
mmol) and Et3N (24 µL, 0.17 mmol) was stirred for 1 week at room
temperature. Purification by gel chromatography (Sephadex LH-20;
eluent, methanol/CH2Cl2 (4:1)) and recrystallization from CH2Cl2-
methanol/diethyl ether afforded orange-red crystals and small amounts
of [Et3NH]BF4. The crystals were washed with water to remove the
ammonium salt and recrystallized from CH2Cl2-methanol/diethyl ether
-
to give pure crystals of 12a+BF4 (141 mg, 71%): 1H NMR (CDCl3)
1
2
2
3
(5-C, JCH ) 167, JCH ) 7 Hz), 113.0 (3-C, JCH < 2, JCH ) 5 Hz),
δ 1.91 (br s, 2 H, NCH2), 2.6-2.8, 3.15-3.35 (m, 4 H each, CH2 of
dppe), 5.59 (br d, 1 H, J ) 6.5 Hz, COCH), 6.29 (br d, 1 H, J ) 6.5
Hz, NCH2CH), 6.9-7.4 (m, 40 H, Ph of dppe); 13C{1H} NMR (CD2-
Cl2) δ 32.8 (CH2 of dppe, quint, JCP ) 9 Hz), 52.7 (NCH2), 124.0
(COCH), 128-135 (Ph of dppe), 142.6 (NCH2CH), 165.0 (CO); 31P-
1
2
128-136 (Ph of dppe), 143.5 (4-C, JCH ) 190, JCH ) 4 Hz), 159.4
(2-C, 3JCH ) 10 (4-H), < 2 (5-H) Hz); 31P{1H} NMR (CDCl3) δ 29-
34 (m); IR (KBr) 1732 (ν(CdO)), 1252, 1028 (ν(SdO)) cm-1. Anal.
Calcd for C58H55N2O4.5FP4S2BrW: C, 52.66; H, 4.19; N, 2.12; S, 4.85;
Br, 6.04. Found: C, 52.46; H, 4.19; N, 2.09; S, 4.61; Br, 6.19.
{1H} NMR (CDCl3) δ 30.8 (d with 183W satellites, JPF ) 43, JPW
)
286 Hz); IR (KBr) 1686 (ν(CdO)) cm-1
.
Anal. Calcd for
Preparation of trans-[WF{NNCH(OMe)CHdCBrCO}(dppe)2]-
-
[BF4]‚CH2Cl2 (18+BF4-‚CH2Cl2). A reaction of 11a+BF4 (80 mg,
C56H52N2OBF5P4W: C, 56.88; H, 4.43; N, 2.37. Found: C, 56.59; H,
4.54; N, 2.29.
0.0677 mmol) with NBS (24.1 mg, 0.135 mmol) and Et3N (10 µL,
0.072 mmol) in THF (5 mL) was conducted similarly to the preparation
of 17. The resulting solution was diluted with CH2Cl2 (20 mL) and
washed with 5% aqueous NH4BF4 (2 × 50 mL). The organic layer
was dried over MgSO4 and evaporated to dryness. The 1H NMR
spectrum of the residual oil exhibited a pair of doublets at δ 5.21 and
6.92 (J ) 2.2 Hz) which are tentatively assigned as the ring protons of
16+. Orange crystals obtained after purification by gel chromatography
(Sephadex LH-20; eluent, methanol/CH2Cl2 (4:1)) and crystallization
from CH2Cl2-methanol/diethyl ether consisted of 16+ and 18+ in ∼1:1
ratio. They were dissolved in methanol (5 mL) and heated at 50 °C for
12 h to complete the conversion to 18+. The solution was diluted with
CH2Cl2 (20 mL) and washed with 5% aqueous NH4BF4 (2 × 50 mL),
and further recrystallization from CH2Cl2-methanol/diethyl ether gave
Its molybdenum analogue trans-[MoF(NNCH2CHdCHCO)(dppe)2]-
[BF4] (12b+BF4-) was prepared similarly from 11b+BF4- in 50% yield.
Purple crystals from CH2Cl2/hexane: 1H NMR (CDCl3) δ 2.19 (br s,
2 H, NCH2), 2.55-2.75, 3.1-3.3 (m, 4 H each, CH2 of dppe), 5.50 (br
d, 1 H, J ) 6.4 Hz, COCH), 6.36 (br d, 1 H, J ) 6.4 Hz, CH2CH),
7.0-7.4 (m, 40 H, Ph of dppe); IR (KBr) 1694 (ν(CdO)) cm-1. Anal.
Calcd for C56H52N2OBF5P4Mo: C, 61.44; H, 4.79; N, 2.56. Found:
C, 61.31; H, 4.91; N, 2.67.
Isomerization of 11a+ to 12a+. 1. Acidic Conditions. To a
-
solution of 11a+BF4 (20 mg, 17 µmol) in CDCl3/CD3OD (4:1, 0.6
mL) was added DCl/D2O (20%, 0.1 mL). The mixture was shaken
1
for a few minutes and analyzed by H NMR. The deuteration at the
3-position and the isomerization to 12a+ were monitored periodically
over two weeks. The products ratio was estimated on the basis of the
integrated intensities of the heterocyclic ring protons. The pseudo-
first-order rate constant for the deuteration and isomerization were
estimated to be 5.7 × 10-1 h-1 (half-life period 1.2 h) at 23 ( 2 °C
and 1.2 × 10-2 h-1 (half-life period 58 h) at 23 ( 2 °C, respectively.
2. Basic Conditions. To a solution of 11a+BF4- (20 mg, 17 µmol)
in CDCl3/CD3OD (4:1, 0.6 mL) or CDCl3 (0.6 mL) was added PhCH2-
-
orange crystals of 18+BF4 containing 0.5CH2Cl2 (37.1 mg, ∼41%).
A single crystal for X-ray diffraction measurement was selected from
them. Analytical sample formulated as 18+BF4-‚CH2Cl2 was obtained
by further recrystallization from CH2Cl2/diethyl ether: 1H NMR
(CDCl3) δ 2.3-2.5 (m, 2 H, CH2 of dppe), 2.60 (s, 3 H, OCH3), 2.9-
3.3 (m, 6 H, CH2 of dppe), 4.60 (d, 1 H, J ) 1.9 Hz, NCH), 6.86 (d,
1 H, J ) 1.9 Hz, NCH(OMe)CH), 7.0-7.4 (m, 40 H, Ph of dppe); 13
C
NMR (CD2Cl2) δ 30-31 (CH2 of dppe), 51.8 (OCH3, 1JCH ) 144, 3JCH
1
NMe2 (2.5 µL, 17 µmol), and the reaction was followed by H NMR
1
2
3
) 7 Hz), 87.6 (5-C, JCH ) 167, JCH ) 5, JCH < 5 Hz), 119.2 (3-C,
in a manner similar to that described above. The deuteration at the
3-position of 11a+ in CDCl3/CD3OD (4:1) completed within 30 min,
and the rate constant for the isomerization to 12a+ was 8.3 × 10-4 h-1
(half-life period 36 days, at 23 ( 2 °C). In contrast, the rate constant
for the isomerization in CDCl3 was much larger (9.4 × 10-3 h-1, half-
life period 74 h at 23 ( 2 °C).
2JCH < 2, JCH ) 4 Hz), 128-137 (Ph of dppe), 138.8 (4-C, JCH
)
3
1
184, JCH ) 3 Hz), 159.1 (2-C, JCH ) 9 (4-H), < 2 (5-H) Hz); 31P-
2
3
{1H} NMR (CDCl3) δ 29.5 (br d with 183W satellites, JPF ) 43, JPW
)
289 Hz); IR (KBr) 1728 (ν(CdO)), 1605 (ν(CdC)) cm-1. Anal. Calcd
for C58H55N2O2BF5P4Cl2BrW: C, 50.61; H, 4.03; N, 2.04. Found: C,
50.63; H, 3.97; N, 1.95.
Preparation of trans-[WF{NNCH(SSO3)CHdCBrCO}(dppe)2]‚0.5-
(diethyl ether) (17‚0.5(diethyl ether)). To a THF (5 mL) suspension
of 11a+BF4- (100 mg, 0.0846 mmol) were added NBS (30.1 mg, 0.169
Crystallography. Crystals suitable for X-ray analysis were sealed
in Pyrex glass capillaries under an argon atmosphere and used for data
collection. Diffraction data were collected on a Rigaku AFC-7R four-

Lactams Based on Organohydrazido(2-) Ligands
Inorganic Chemistry, Vol. 36, No. 2, 1997 171
circle automated diffractometer with Mo KR (λ ) 0.710 69 Å) radiation
and a graphite monochromator at 20 ( 1 °C. Accurate cell dimensions
of each crystal were determined by least-squares refinement of 25
machine-centered reflections. Empirical absorption correction based
on ψ scan and Lorentz-polarization corrections were applied. Details
of the X-ray diffraction study are summarized in Table 7.
ref 26, and anomalous dispersion effects were included; the values for
∆f ′ and ∆f ′′ were taken from ref 27.
Acknowledgment. We are grateful for financial support from
a Grant-in-Aid for Scientific Research from the Ministry of
Education, Science and Culture of Japan.
The structure solution and refinement were performed by using the
TEXSAN (Molecular Structure Corp.) program package. The structures
were solved by a combination of heavy-atom Patterson methods and
Fourier techniques. All non-hydrogen atoms were found from the
difference Fourier maps and refined by full-matrix least-squares
techniques with anisotropic thermal parameters, except for the carbon
atom of the CH2Cl2 molecule in 18+BF4-‚0.5CH2Cl2, where isotropic
parameters were used. All hydrogen atoms were placed at calculated
positions and were included in the final stage of refinements with fixed
isotropic parameters. The atomic scattering factors were taken from
Supporting Information Available: X-ray crystallographic files
in CIF format are available for 3a‚0.5C6H6, 11a+BF4-, 12a+BF4-, and
18+BF4-‚0.5CH2Cl2 on the Internet only. Access information is given
on any current masthead page.
IC960778E
(26) International Tables for X-ray Crystallography; Kynoch Press: Bir-
mingham, England, 1974; Vol. IV.
(27) International Tables for X-ray Crystallography; Kluwer Academic
Publishers: Boston, MA, 1992; Vol. C.