Mono-indenyl and cyclopentadienyl derivatives of molybdenum(IV) with a 16 valence-electron configuration

Article abstract of DOI:10.1016/S0022-328X(02)01701-1

Reactions of (ring)MoCl₃ [ring=cyclopentadienyl, η⁵-C₅H₅ (Cp) and indenyl η⁵-C₉H₇ (Ind)] with salts of the N,N-diethyldithiocarbamate (S₂CNEt₂)-, O,O′-dieth

Full text of DOI:10.1016/S0022-328X(02)01701-1

Journal of Organometallic Chemistry 663 (2002) 78ꢄ82
/
www.elsevier.com/locate/jorganchem
Mono-indenyl and cyclopentadienyl derivatives of molybdenum(IV)
with a 16 valence-electron configuration
Carlos C. Romao ꢀ, Beatriz Royo
˜
´ ´
Instituto de Tecnologia Quımica e Biologica da Universidade Nova de Lisboa, Quinta do Marqueˆs, EAN, Av. da Republica, Apartado 127, 2781-901
Oeiras, Portugal
Received 16 May 2002; accepted 3 June 2002
Abstract
Reactions of (ring)MoCl3 [ringꢁ
cyclopentadienyl, h5-C5H5 (Cp) and indenyl h5-C9H7 (Ind)] with salts of the N,N-
/
diethyldithiocarbamate (S2CNEt2)ꢂ, O,O?-diethyldithiophosphate [S2P(OEt)2]ꢂ, N,N?-diphenylformamidinate [CH(NPh)2]ꢂ
,
acetate (O2CCH3)ꢂ and acetylacetonate [CH3COCH(O)CH3]ꢂ (acac)ꢂ anions yield the molybdenum(IV) complexes of the type
(ring)MoCl2X. Characterisation of new compounds by elemental analysis, IR and 1H-NMR spectroscopy and magnetic
susceptibility measurements is discussed.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: Indenyl; Cyclopentadienyl; Molybdenum; Dithiocarbamate; Dithiophosphate; Amidine; Acetylacetonate; Acetate
1. Introduction
(oxidation of CpMCl2; reduction of CpMCl4 and
conproportionation of CpMCl2 and CpMCl4 and covers
a number of phosphine adducts of the type Cp?MX3L
To date, the chemistry of monocyclopentadienyl
molybdenum(IV) complexes and its ring-substituted
analogues remains relatively undeveloped and can be
confined to a handful of compounds. Without being
exhaustive, we believe that the earlier examples are the
and Cp?MX3L2 (Lꢁdppe [7], dmpe [7] and PMe2Ph [4])
/
either as the chlorides or hydrides. The more exotic
CpꢀMoHCl(PPh2)(PMe3) also belongs to this family [8],
as well as [CpMoCl4]ꢂ [9] and the related family of
thiolates, [CpMo(SR)4]ꢂ, e.g. [CpMo{S2C2(CN)2}2]ꢂ
[10] and [CpMo{SC6F5}4]ꢂ [11]. Recently, Royo and
coworkers prepared the O,O?-diethyl-dithiophosphate
derivative CpꢀMoCl2{S2P(OEt)2} by reduction of
CpꢀMoCl3{S2P(OEt)2} [12].
The mono-indenyl analogues are still fewer. In-
dMoCl3 was first cited in patent literature [13] and we
recently reported its synthesis via decarbonylation of
IndMoCl3(CO)2 according to the procedure discovered
by Poli for CpMoX3 [14].
In order to extend the scope of the chemistry of the
(ring)Mo(IV) fragment, we decided to explore the
synthesis of (ring)M(IV)Ln complexes directly from
the available starting trihalides, (ring)MoCl3 a method
so far only used for some of the CpMoX3(PR3)2
complexes mentioned above. In this work we report
the synthesis of half-sandwich molybdenum(IV) com-
dicarbonyls CpMoX3(CO)2 (XꢁCl, Br, I) obtained by
/
X2 oxidation of either Cp2Mo2(CO)6 or CpMo(CO)3X
[1]. The cyanide derivative CpMo(CN)3(CO)2 was
obtained by CNꢂ substitution on the parent iodide
[2]. Related phosphine derivatives, CpMoX3L2 (L2ꢁ
dppe, dmpe; LꢁPMe3, PMe2Ph; XꢁCl, Br, H) were
also reported by the group of Green [3]. The trihydrides
with Lꢁdmpe, PMe3, PMe2Ph induce catalytic H/D
exchange in sp3 and sp2 CÃ
H bonds under photolytic
conditions [4]. However, the synthesis of the simple
derivatives CpMoX3 (Xꢁ
/
/
/
/
/
/
Cl, Br or I) [5] and (h5-
C5Me5)MoCl3 by Poli and coworkers [6], is considerably
more recent. It comprises a variety of synthetic methods
ꢀ Corresponding author. Tel.:
4411277
E-mail address: ccr@itqb.unl.pt (C.C. Romao).
ꢃ/
351-1-4418407; fax:
ꢃ351-1-
/
plexes of the type (ring)MoCl2X [ringꢁcyclopentadie-
/
˜
0022-328X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 7 0 1 - 1

C.C. Romao, B. Royo / Journal of Organometallic Chemistry 663 (2002) 78ꢄ
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82
79
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nyl, h5-C5H5 (Cp) or indenyl h5-C9H7 (Ind) and Xꢁ
S2CNEt2, S2P(OEt)2, CH(NPh)2, O2CCH3 and acac].
/
acetate in dichloromethane yields the corresponding
(ring)MoCl2(acac) [ringꢁCp (5); Ind (6)] and (ring)Mo-
Cl2(OOCCH3) [ringꢁCp (7); Ind (8)], respectively (see
Scheme 1).
The formulation of complexes 1ꢄ
/
/
/
8 as mononuclear 16
2. Results and discussion
electron compounds is consistent with their spectral
properties and magnetic behaviour. Thus, all these
complexes are paramagnetic with magnetic values in
accord with the spin-only value calculated for two
unpaired electrons (2.83 mB). The paramagnetic beha-
The reaction of (ring)MoCl3 (ringꢁCp and Ind) with
/
the ammonium salt of the O,O?-diethyldithiophosphate
[S2P(OEt)2]ꢂ anion affords the molybdenum(IV) dithio-
phosphate complexes (ring)MoCl2[S2P(OEt)2] [ringꢁ
/
viour for complexes 1ꢄ8 with values between 2.14 and
/
Cp (1); Ind (2)] (see Scheme 1). Their IR spectra show
a n(PS) absorption at 640 and 644 cmꢂ1 attributable to
a chelated dithiophosphate ligand [12]. Similar reaction
carried out using the silver salt of N,N-diethyldithio-
carbamate ligand AgS2CNEt2 in dichloromethane af-
fords the dithiocarbamate complexes (ring)MoCl2-
2.83 BM at 300 K is consistent with the spin triplet state
expected for a pseudo-square pyramidal compound [15].
Magnetic moments for (ring)Mo(IV) compounds with
this geometry have only been reported for the following
16 electron species: CpꢀMoCl3(PMe3) [6] (meff
ꢁ2.63 mB)
/
and CpꢀMoCl2[S2P(OEt)2] [12] (meff 2.75 mB).
ꢁ
/
[S2CNEt2] [ringꢁCp (3); Ind (4)] (see Scheme 1). The
/
In the case of the dithiophosphate derivative 1, the
monomeric formulation has also been confirmed by
MALDI-TOF mass spectrometry.
IR spectra of both dithiocarbamate complexes 3 and 4
show a strong n(CN) absorption at 1518 and 1512 cmꢂ1
and a n(CS) absorption at 1076 and 1075 cmꢂ1
,
1H-NMR was recorded for compounds 1ꢄ
/
8. Their
spectra showed broad resonances, in the range between
d 1 and 8 ppm, with unresolved HꢄH coupling due to
respectively, attributable to a bidentate [S2CNEt2]
ligand [12].
/
We have extended our studies to the synthesis of other
molybdenum(IV) complexes with isoelectronic pseudo-
allylic ligands containing nitrogen and oxygen atoms
instead of sulphur. The reaction of (ring)MoCl3 with
one equivalent of thallium acetylacetonate or silver
line broadening, except for the dithiocarbamates
CpMoCl2[S2CNEt2] (3) and IndMoCl2[S2CNEt2] (4).
1
The H-NMR spectrum of 3 showed one signal for the
cyclopentadienyl ring protons and two sets of signals for
Scheme 1.

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C.C. Romao, B. Royo / Journal of Organometallic Chemistry 663 (2002) 78ꢄ
/
82
˜
non-equivalent ethyl groups, due to the different endo
1
and exo orientations of the two ethyl groups. The H-
NMR spectrum of 4 showed three resonances for the
indenyl ligand at d 5.41, 5.61 and 7.18ꢄ7.31 and two
/
sets of signals for non-equivalent ethyl groups.
The reaction of (ring)MoCl3 with one equivalent of
silver formamidinate AgCH(NPh)2 in dichloromethane
Fig. 2. Labelled carbon atoms of the indenyl ring.
affords (ring)MoCl2[CH(NPh)2] [ringꢁCp (9); Ind
/
for months but decomposition is observed if stored in
solution. They are soluble in dichloromethane and
insoluble in hexane, pentane, toluene and ether. Un-
fortunately, efforts to obtain single crystals for X-ray
diffraction studies were unsuccesful.
(10)]. In contrast to the other mononuclear
(ring)Mo(IV) complexes described herein, the amidinato
complexes 9 and 10 are diamagnetic, as evidenced by
1
sharp, well resolved, H-NMR spectra. This quite likely
reflects the presence of a strong field ligand. A pseudo-
square pyramidal molybdenum with a 16 electron
configuration (a d2 metal) can in principle be found in
two different spin states: a diamagnetic state, where the
two metal electrons are coupled in the dxy orbital and
the dz2 orbital remains empty, or a triplet state, where
the two metal frontier orbitals hold one electron each
[16]. (ring)Mo(IV) complexes of the types I, II and III
are usually paramagnetic with a triplet state (see Fig. 1).
Exceptions have been reported in the literature when
strong p-donor ligands are present. This is the case of
CpꢀMoHCl(PPh2)(PMe3) [8] which has a singlet ground
state, certainly the result of the strong p-interaction of
the phosphido ligand. Similar diamagnetic behaviour is
observed for the tetrathiolato derivatives [CpMo-
(SR)4]ꢂ [17]. The isoelectronic CpꢀReCl3Me derivative
has been reported to exhibit spin-crossover behaviour
3. Conclusion
The easily available (ring)MoCl3 compounds can be
used directly to prepare a number of derivatives in
which one bidentate ligand replaces one chloride form-
ing pentacoordinate complexes of general formula
(ring)MoCl2X (Xꢁbidentate anionic N2, O2, S2 do-
/
nors). With the exception of the formamidinate deriva-
tives all complexes are paramagnetic with two unpaired
electrons.
4. Experimental
1
4.1. Materials and procedures
[18]. The H-NMR spectrum of the amidinato complex
10 was recorded at 90 8C showing unshifted resonances
which indicates a singlet ground state. At higher
temperature decomposition of the sample was observed.
The 1H-NMR spectrum of 9 shows a singlet at d 8.10
All operations were carried out under an atmosphere
of dinitrogen with standar Schlenk-line and glove-box
techniques. Solvents were purified by conventional
methods and distilled under nitrogen prior to use.
NMR spectra were measured on a Bruker CXP 300
spectrometer, and IR spectra were measured on a
Unicam Mattson model 7000 FTIR spectrometer. Ele-
mental analyses were performed in our laboratories
(ITQB). Magnetic moments have been determined at
for the proton of the CH and a multiplet at d 7.17ꢄ7.38
/
for the phenyl protons of the amidinato ligand. The
cyclopentadienyl protons give a resonance at d 5.23.
Compound 10 gives a singlet at d 8.35 for the proton of
the CH and a multiplet at d 7.07ꢄ7.48 for the phenyl
/
protons of the amidinato ligand and a doublet at d 5.59
(H1/3), a triplet at d 5.41 (H2) and a multiplet at d 6.88
(H5ꢄ8) for the indenyl ligand (see Fig. 2).
room temperature (r.t.) with a JohnsonꢄMatthey mag-
/
netic susceptibility balance and were corrected for
diamagnetic contributions of the ligands by using
Pascal’s constants before conversion to magnetic mo-
ments. MALDI mass measurements were performed on
a Reflex time-of-flight instrument (Bruker-Franzen
Analytik, Bremen, Germany) equipped with a SCOUT
ion source, operating in the positive reflection mode
with pulsed extraction. Ions were formed by a pulsed
All the complexes 1ꢄ
/
10 are air-sensitive compounds.
They can be stored as a solids under inert atmosphere
UV laser beam (nitrogen laser, lꢁ
was required for the ionization of the sample. External
mass calibration was made by using the [Mꢃ
H]ꢃ ion of
/
337 nm). No matrix
/
a-cyano-4-hydroxycinnamic and angiotensin II.
All common chemicals and solventes were purchased
from commercial suppliers. The synthesis of N,N?-
diphenylformamidinato [19], CpMoCl3 [5] and In-
Fig. 1. Mo(IV) complexes of the type[(ring)MoX2L2]ꢃ
/
(I),
(ring)MoX3L(II) and [(ring)MoX4]ꢂ(III).
/

C.C. Romao, B. Royo / Journal of Organometallic Chemistry 663 (2002) 78ꢄ
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82
81
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dMoCl3 [14] was prepared according to literature
procedure. Thallium acetylacetonate was prepared by
reaction of acetylacetone with thallium ethoxide in
toluene at r.t.
was stirred for 10 h and the solution was filtered. The
filtrate was taken to dryness to yield the title compound
4 as a brown solid which was washed with Et2O (3ꢅ
ml). Yield: 0.34 g (85%). Selected IR (KBr, cmꢂ1) 1512,
vs, n(CN)asym 1075, vs, n(CS). Anal. Calc. for
/
5
,
4.2. Preparation of CpMoCl2[S2P(OEt)2] (1)
C14H17Cl2MoNS2: C, 39.08; H, 3.98; N, 3.26. Found:
1
C, 39.02; H, 3.83; N, 2.97%. H-NMR (C6D6, 25 8C, d
Solid ammonium diethyldithiophosphate (0.21 g, 1.04
mmol) was added to a suspension of CpMoCl3 (0.28 g,
1.04 mmol) in 40 ml of CH2Cl2 at r.t. The purple-brown
color of the suspension changed to give a brown
suspension after stirring for 10 h. The reaction mixture
was filtered and the filtrate was concentrated to dryness.
ppm): 7.18ꢄ
H2); 3.93 (br m, ethyl); 1.55 (br m, ethyl), 1.26 (br m,
ethyl). meff
2.63 mB.
/
7.31 (m, H5ꢄ8); 5.61 (d, H1/3); 5.41 (t, 1H,
ꢁ
/
4.6. Preparation of CpMoCl2(acac) (5)
The solid residue was washed with Et2O (3ꢅ
/
5 ml).
To a suspension of CpMoCl3 (0.3 g, 1.12 mmol) in 50
ml of CH2Cl2 was added Tl(acac) as a solid (0.34 g, 1.12
mmol) at r.t. The reaction mixture was stirred for 10 h
and the solution was filtered. The filtrate was taken to
Compound 1 was isolated as a brown solid. Yield: 0.35 g
(82%). Selected IR (KBr, cmꢂ1): 1006, vs, 960, vs
n(POC)asym, 812, vs, 792, vs n(POC)sym, 640, vs, n(PS).
Anal. Calc. for C9H15Cl2MoO2PS2: C, 25.91; H, 3.62.
dryness and the residue was washed with Et2O (3ꢅ5 ml)
/
Found: C, 26.02; H, 3.52%. meff
[Mꢃ].
ꢁ
/
2.45 mB. MS: 418
to yield the title compound 5 as a brown solid. Yield:
0.28 g (76%). Selected IR (KBr, cmꢂ1): 1521, vs, n(CO).
Anal. Calc. for C10H12Cl2MoO2: C, 36.28; H, 3.65.
4.3. Preparation of IndMoCl2[S2P(OEt)2] (2)
Found: C, 36.10; H, 3.72%. meff
ꢁ2.21 mB.
/
Solid ammonium diethyldithiophosphate (0.19 g. 0.94
mmol) was added to a stirred suspension of IndMoCl3
(0.3 g, 0.94 mmol) in 30 ml of CH2Cl2 at r.t. The
reaction was completed after 10 h stirring leading a
brown solution. The solution was filtered and the filtrate
was concentrated to dryness to give 2 as a brown solid,
4.7. Preparation of IndMoCl2(acac) (6)
To a suspension of IndMoCl3 (0.20 g, 0.66 mmol) in
40 ml of CH2Cl2 was added Tl(acac) as a solid (0.20 g,
0.66 mmol) at r.t. The reaction mixture was stirred for
10 h and the solution was filtered. The filtrate was taken
which was washed with Et2O (3ꢅ
/
5 ml). Yield: 0.35 g
to dryness and the residue was washed with Et2O (3ꢅ5
/
(80%). Selected IR (KBr, cmꢂ1): 1008, vs, 956, vs,
n(POC)asym, 758, vs, n(POC)sym, 644, vs n(PS). Anal.
Calc. for C13H17Cl2MoO2PS2: C, 33.42; H, 3.67. Found:
ml) to yield the title compound 6 as a brown solid.
Yield: 0.18 g (72%). Selected IR (KBr, cmꢂ1): 1523, vs,
n(CO). Anal. Calc. for C14H14Cl2MoO2: C, 44.12; H,
C, 33.26; H, 3.58%. meff
ꢁ
/
2.77 mB.
3.70. Found: C, 43.91; H, 4.01%. meff
ꢁ2.58 mB.
/
4.4. Preparation of CpMoCl2(S2CNEt2) (3)
4.8. Preparation of CpMoCl2(OOCMe) (7)
Solid silver diethyldithiocarbamate (0.28 g, 1.12
mmol) was added to a stirred suspension of CpMoCl3
(0.3 g, 1.12 mmol) in 40 ml of CH2Cl2 at r.t. The
reaction mixture was stirred for 10 h and the solution
was filtered. The filtrate was taken to dryness to yield
the title compound 3 as a brown solid, which was
To a stirred suspension of CpMoCl3 (0.3 g, 1.12
mmol) in 40 ml of CH2Cl2 was added AgOOCMe as a
solid (0.18 g, 1.12 mmol) at r.t. The reaction was
complete after 6 h stirring leading to a redꢄbrown
/
solution. The AgCl precipitate was filtered and the
solvent was removed from the filtrate under vacuum to
give a brown residue which after being washed with
washed with Et2O (3ꢅ5 ml). Yield: 0.36 g (86%).
/
Selected IR (KBr, cmꢂ1): 1518, vs, n(CN)asym, 1076,
vs, n(CS). Anal. Calc. for C10H15Cl2MoNS2: C, 31.59;
H, 3.98; N 3.68. Found: C, 31.59; H, 3.83; N, 3.73%. 1H-
NMR (C6D6, 25 8C, d ppm): 4.89 (s, Cp); 3.10 (br m,
Et2O (3ꢅ
solid. Yield: 0.28 g (87%). Selected IR (KBr, cmꢂ1
1548, vs, n(CO). Anal. Calc. for C7H8Cl2MoO2: C,
/5 ml) yield the title compound 7 as a brown
)
28.89; H, 2.77. Found: C, 28.86; H, 3.02%. meff
mB.
ꢁ2.62
/
ethyl); 0.66 (br m, ethyl), 0.78 (br m, ethyl). meff
mB.
ꢁ2.14
/
4.9. Preparation of IndMoCl2 (OOCMe) (8)
4.5. Preparation of IndMoCl2(S2CNEt2) (4)
To a stirred suspension of IndMoCl3 (0.17 g, 0.53
mmol) in 20 ml of CH2Cl2 was added AgOOCMe as a
solid (0.09 g, 0.53 mmol) at r.t. The reaction mixture was
stirred for 6 h and the solution was filtered. The filtrate
Solid silver dithiocarbamate (0.24 g, 0.94 mmol) was
added to a stirred suspension of IndMoCl3 (0.3 g, 0.94
mmol) in 40 ml of CH2Cl2 at r.t. The reaction mixture

82
C.C. Romao, B. Royo / Journal of Organometallic Chemistry 663 (2002) 78ꢄ82
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˜
was taken to dryness and the residue was washed with
References
Et2O (3ꢅ5 ml) to yield the title compound 8 as a brown
/
solid. Yield: 0.16 g (80%). Selected IR (KBr, cmꢂ1):
1537, vs, n(CO). Anal. Calc. for C9H12Cl2MoO2: C,
[1] (a) R.J. Haines, R.S. Nyholm, M.H.B. Stiddard, J. Chem. Soc.
Sect. A (1966) 1606;
(b) M.L.H. Green, W.E. Lindsell, J. Chem. Soc. Sect. A (1967)
686;
38.74; H, 2.96. Found: C, 38.46; H, 2.68%. meff
mB.
ꢁ2.84
/
(c) J.C.T.R. Burckett-St. Laurent, J.S. Fields, R.J. Haines, M.
McMahon, J. Organomet. Chem. 181 (1979) 117.
[2] J.A. Dineen, P.L. Pauson, J. Organomet. Chem. 71 (1974) 91.
4.10. Preparation of CpMoCl2[CH(NPh)2] (9)
[3] T. Aviles, M.L.H. Green, A.R. Dias, C. Romao, J. Chem. Soc.
˜
Dalton Trans. (1979) 1367.
[4] F. Abugideiri, J.C. Fettinger, B. Pleune, R. Poli, C.A. Bayse,
M.B. Hall, Organometallics 16 (1997) 1179.
Solid AgCH(NPh)2 (0.49 g, 1.64 mmol) was added to
a stirred suspension of CpMoCl3 (0.44 g, 1.64 mmol) in
50 ml of CH2Cl2. The reaction mixture was stirred for 10
h and the solution was filtered. The filtrate was taken to
[5] J.C. Gordon, V.T. Lee, R. Poli, Inorg. Chem. 32 (1993) 4460.
[6] F. Abugideiri, G.A. Brewer, J.U. Desai, J.C. Gordon, R. Poli,
Inorg. Chem. 33 (1994) 3745.
dryness and the residue was washed with Et2O (3ꢅ5 ml)
/
[7] R. Poli, M.A. Kelland, J. Organomet. Chem. 419 (1991) 127.
[8] R.T. Baker, J.C. Calabrese, R.L. Harlow, I.D. Williams, Orga-
nometallics 12 (1993) 830.
to yield the title compound 9 as a brown solid. Yield:
0.55 g (78%). Selected IR (KBr, cmꢂ1): 1689, vs,
n(NCN)asym, 1589, vs, 1531, vs, n(CN). Anal. Calc. for
C18H16Cl2MoN2: C, 50.61; H, 3.78; N, 6.56. Found: C,
[9] M. Kilner, C. Midcalf, J. Chem. Soc. Sect. A (1971) 292.
[10] (a) J. Locke, J.A. McCleverty, Inorg. Chem. 5 (1966) 1157;
(b) M.R. Churchill, J. Cooke, J. Chem. Soc. Sect. A (1970) 2046.
[11] J.L. Davidson, W.E. Lindsell, K.J. McCullough, C.H. McIntosh,
Organometallics 14 (1995) 3497.
1
50.57; H, 3.56; N, 6.43%. H-NMR (CD2Cl2, 25 8C, d
ppm): 8.10 (s, 1H); 7.17ꢄ7.38 (m, 10H); 5.23 (s, 5H).
/
[12] M.V. Galakhov, P. Go´mez-Sal, T. Pedraz, M.A. Pellinghelli, P.
Royo, A. Tiripicchio, A. V’zquez de Miguel, J. Organomet.
Chem. 579 (1999) 190.
4.11. Preparation of IndMoCl2[CH(NPh)2] (10)
Solid AgCH(NPh)2 (0.28 g, 0.94 mmol) was added to
a stirred suspension of IndMoCl3 (0.3 g, 0.94 mmol) in
50 ml of CH2Cl2. The reaction mixture was stirred for 10
h and the solution was filtered. The filtrate was taken to
dryness and the residue was washed with Et2O (3ꢅ5 ml)
to yield the title compound 10 as a brown solid. Yield:
0.36 g (82%). Selected IR (KBr, cmꢂ1): 1680, vs,
[13] R.D. Gorsich, U.S. Patent 3,080,305, Mar 5, 1063 Chem. Abstr.,
59 (1963) 3957c.
[14] M.G.B. Drew, V. Fe´lix, I.S. Goncalves, C.C. Romao, B. Royo,
¸
˜
Organometallics 17 (1998) 5782.
[15] (a) R. Poli, Chem. Rev. 96 (1996) 2135;
/
(b) R. Poli, B.E. Owens, S.T. Krueger, A.L. Rheingold, Poly-
hedron 1 (1992) 2301;
(c) F. Abugideiri, J.C. Gordon, R. Poli, B.E. Owens-Waltermire,
A.L. Rheingold, Organometallics 12 (1993) 1575.
[16] (a) P. Kuba´cek, R. Hoffmann, Z. Havlas, Organometallics 1
(1982) 180;
n(NCN)asym
,
1564, vs, n(CN). Anal. Calc. for
C22H18Cl2MoN2: C, 55.37; H, 3.80; N, 5.87. Found:
1
C, 55.57; H, 3.98; N, 5.96%. H-NMR (CD2Cl2, 25 8C,
(b) R. Poli, Organometallics 9 (1990) 1892.
d ppm): 8.35 (s, 1H); 7.07ꢄ7.48 (m, 10H); 6.88 (m, 4H,
/
[17] (a) W.A.W. Abu Bakar, J.L. Davidson, W.E. Lindsell, K.J.
McCullogh, J. Chem. Soc. Dalton Trans. (1990) 61;
(b) W.A.W. Abu Bakar, J.L. Davidson, W.E. Lindsell, K.J.
McCullogh, K.W. Muir, J. Chem. Soc. Dalton Trans. (1989) 991.
H5ꢄ8); 5.59 (d, 2H, H1/3); 5.41 (t, 1H, H2).
Acknowledgements
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This work was supported by PRAXIS XXI under
project 2/2.1/QUI/316/94. B.R. thanks PRAXIS XXI for
a postdoctoral grant.