Hydride, halide, methyl, carbonyl, and chalcogenido derivatives of permethylmolybdenocene

Article abstract of DOI:10.1016/j.ica.2005.12.037

Cp₂^* MoCl₂ (Cp* = C₅Me₅) is obtained via reaction of MoCl₅ with a mixture of Cp*K and NaBH₄ followed by treatment with CHCl₃. Cp₂^* MoCl₂ provides access to a large variety of other permethylmolybdenocene complexes which include {Mathematical expression} (E = S, Se, Te), Cp₂^* Mo ( η² - E₂ ) (E = S, Se, Te), Cp₂^* Mo ( η² - E₄ ) (E = S, Se), Cp₂^* Mo ( OSiMe₃ ) CN, Cp₂^* Mo ( NCS )₂, and Cp₂^* Mo ( N₃ )₂.

Full text of DOI:10.1016/j.ica.2005.12.037

Inorganica Chimica Acta 359 (2006) 2942–2955
www.elsevier.com/locate/ica
Hydride, halide, methyl, carbonyl, and chalcogenido derivatives of
permethylmolybdenocene
1
2
3
*
Jun Ho Shin , David G. Churchill , Brian M. Bridgewater , Keliang Pang, Gerard Parkin
Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027, USA
Received 15 November 2005; accepted 11 December 2005
Available online 28 February 2006
Dedicated with respect to Professor Brian James on the occasion of his 70th birthday.
Abstract
Cpꢀ2MoCl2 (Cp* = C5Me5) is obtained via reaction of MoCl5 with a mixture of Cp*K and NaBH4 followed by treatment with CHCl3.
Cpꢀ2MoCl2 provides access to a large variety of other permethylmolybdenocene complexes which include Cpꢀ2MoH2; Cp2ꢀMoMe2;
Cpꢀ2MoCO; CpꢀMoO; Cpꢀ2MoðMeÞCl; Cp2ꢀMoðHÞI; Cp2ꢀMoðEPhÞH (E = S, Se, Te), Cpꢀ2Moðg2-E2Þ (E = S, Se, Te), Cp2ꢀMoðg2-E4Þ
(E = S, Se), Cpꢀ2MoðOSiMe3ÞCN; CpꢀMoðNCSÞ , and CpꢀMoðN3Þ2.
2
2
2
2
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Permethylmolybdenocene; Molybdenum; Hydride; Methyl; Carbonyl; Oxo; Chalcogenido
1. Introduction
investigated, although the complete development of this
area has been hampered by synthetic difficulties. In partic-
ular, the chemistry of peralkylated- and perarylatedmolyb-
denocene systems is rather poorly developed due to
inefficient and inconvenient synthetic methods. For exam-
ple, the novel perphenylmolybdenocene complex
{(C5Ph5)2Mo} is obtained in very low yield (7%) via reac-
tion of Mo(CO)6 with Ph2C2 [10]. The first report of the
permethylmolybdenocene system appeared in 1973 with
the synthesis of Cp2ꢀMoH2 (Cp* = C5Me5) and several
other derivatives [11], but there were no subsequent reports
Molybdenocene and tungstenocene complexes, first pre-
pared in 1954 [1], have played a prominent role in the
development of organometallic chemistry following the
synthesis of the dihydrides Cp2MH2 (M = Mo, W) in
1959 [2].4 In addition to extensive studies on the parent
molybdenocene system [4,5], the chemistry of monosubsti-
tuted ring derivatives such as (CpMe)2MoX2 [6] and
t
ðCpBu Þ MoX2 [7], mixed-ring and indenyl complexes [8],
2
and ansa molybdenocene compounds [9] have also been
*
Corresponding author.
E-mail address: parkin@columbia.edu (G. Parkin).
1
Present address: Department of Chemistry, Queensborough Community College, Bayside, NY 11364, USA.
Present address: Department of Chemistry and School of Molecular Science (BK 21), KAIST, Daejeon 305-701, Republic of Korea.
Present address: Rohm and Haas Company, Spring House, PA 19002, USA.
2
3
4
A certain degree of confusion exists with the first report of the dihydrides Cp2MH2. Specifically, some authors [3a,3b] cite the first report as being 1961
[3c], while others [3d] believe that the 1959 [3e] report involved the reaction of MoCl5, NaCp, and NaBH4. The 1959 synthesis actually involved the
reaction of ‘‘di-p-cyclopentadienyl halides of molybdenum’’ with NaBH4 [3e]. Although the specific ‘‘di-p-cyclopentadienyl halides of molybdenum’’ used
for the first synthesis were not explicitly stated, examination of the references indicates that the term refers to either [Cp2MoCl][Cr(CNS)4(NH3)2] Æ H2O or
[Cp2MoCl2]2[PtCl6] [3f]. The first synthesis of Cp2MoH2 using MoCl5 as the molybdenum reagent was reported in 1960 and involved reaction with only
NaCp [3g]; the reaction that involved the use of NaBH4 as an additional hydride reagent was reported in 1961 [3c]. Thus, it is evident that the first report of
Cp2MoH2 was in 1959 [3e], but the first synthesis involving the reaction of MoCl5, NaCp, and NaBH4 was in 1961 [3c].
0020-1693/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.12.037

J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
2943
until 1991 when Cloke et al. synthesized Cpꢀ2MoH2 by
using metal vapor synthesis techniques [12]. The lack of
studies on the permethylmolybdenocene system during
the period 1973–1991 may be attributed to the fact that
other researchers were unable to substantiate the 1973 syn-
thesis of Cpꢀ2MoH2 [11], while Ito has noted that a modified
method of synthesis gives Cpꢀ2MoH2 in insufficient yield for
it to be useful as a starting material for subsequent derivi-
tization [3a,13]. Furthermore, Cloke et al. have also
questioned the formulation of the proposed permethyl-
molybdenocene compound fCpꢀ2Mog described in the
1973 paper [12]. In this paper, we report the preparation
of the dichloride Cpꢀ2MoCl2 by using conventional syn-
thetic methods, and thereby provide a convenient entry
point for a variety of permethylmolybdenocene derivatives.
2. Results and discussion
2.1. Synthesis and reactivity of Cpꢀ2MoCl2
ꢀ
˚
Fig. 1. Molecular structure of Cp2MoCl2. Selected bond lengths (A) and
angles (ꢁ): Mo–Cl(1) 2.462(2), Mo–Cl(2) 2.466(2); Cl(1)–Mo–Cl(2)
81.00(9).
Access to permethylmolybdenocene chemistry is conve-
niently provided by Cp2ꢀMoCl2 which is obtained via a
two step sequence involving (i) the reaction of MoCl5 with
a mixture of Cp*K and NaBH4 to give crude CpꢀMoH ,
2
2
followed by (ii) addition of CHCl3 (Scheme 1) [14]. The lat-
ter step is an important improvement over the previous
method because the lower solubility of Cpꢀ2MoCl2 in pen-
tane compared to Cpꢀ2MoH2 facilitates isolation of the
permethylmolybdenocene derivative. The tetramethylethyl-
cyclopentadienyl counterpart ðCpMe EtÞ MoCl2 has also
4
2
been obtained in an analogous manner, and the molecular
structures of Cpꢀ2MoCl2 and ðCpMe EtÞ MoCl2 as deter-
4
2
mined by X-ray diffraction are illustrated in Figs. 1 and 2.
Cpꢀ2MoCl2 is a useful precursor for a variety of other
permethylmolybdenocene derivatives which include
hydride, alkyl, carbonyl and oxo complexes (Scheme 2).
Thus, Cpꢀ2MoCl2 reacts with: (i) LiAlH4 to give
Cpꢀ2MoH2, (ii) MeLi to give Cp2ꢀMoMe2, (iii) Na(Hg) in
the presence of CO to give Cpꢀ2MoCO and (iv) LiOH to
give Cpꢀ2MoO, as illustrated in Scheme 2. The molecular
structures of Cpꢀ2MoH2; Cp2ꢀMoMe2; Cpꢀ2MoCO and
Cpꢀ2MoO have been determined by X-ray diffraction, as
shown in Figs. 3–6. The oxo complex has been previously
reported but has only been obtained as a minor impurity
resulting from the work-up procedure following the reac-
tion of molybdenum atoms with Cp*H [12].
4Et
Fig. 2. Molecular structure of ðCpMe Þ2MoCl2. Selected bond lengths
˚
(A) and angles (ꢁ): Mo–Cl(1) 2.477(1), Mo–Cl(2) 2.475(1); Cl(1)–Mo–Cl(2)
80.63(3).
2.2. Reactivity of Cpꢀ2MoH2; Cp2ꢀMoMe2 and Cpꢀ2Mo(CO)
The dihydride, dimethyl and carbonyl complexes,
Cpꢀ2MoH2; Cp2ꢀMoMe2 and Cpꢀ2MoðCOÞ,
provide
a
means to obtain permethylmolybdenocene compounds that
feature more than one substituent. For example, the
Scheme 1.

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J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
Scheme 2.
ꢀ
˚
ꢀ
Fig. 4. Molecular structure of Cp2MoMe2. Selected bond lengths (A) and
˚
Fig. 3. Molecular structure of Cp2MoH2. Selected bond lengths (A) and
angles (ꢁ): Mo–C(1) 2.234(3), Mo–C(2) 2.239(3); C(1)–Mo–C(2) 78.4(1).
angles (ꢁ): Mo–H(1) 1.61(4), Mo–H(2) 1.64(4); H(1)–Mo–H(2) 70.3(18).
dimethyl Cpꢀ2MoMe2 reacts with HCl to yield the methyl-
chloride Cpꢀ2MoðMeÞCl (Scheme 3) while the dihydride
Cpꢀ2MoH2 reacts with MeI to give the hydride-iodide
Cpꢀ2MoðHÞI (Scheme 4), which has been structurally char-
acterized by X-ray diffraction (Fig. 7). The isolation of the
latter complex is noteworthy in view of the fact that reac-
tion of Cpꢀ2MoH2 with ICH2CH2I yields the diiodide
fCpꢀ2MoðCOÞMegI may be obtained via treatment of
Cpꢀ2MoðCOÞ with MeI (Scheme 5).
The methyl-chloride complex Cpꢀ2MoðMeÞCl reacts with
LiAlH4 to yield the ‘‘tuck-in’’ complex Cp*(g5,g1-
C5Me4CH2)MoH (Scheme 3) which has previously been
obtained via photolysis of Cpꢀ2MoH2 [12]. The ‘‘tuck-in’’
complex Cp*(g5,g1-C5Me4CH2)MoH is presumably
obtained as a consequence of facile elimination of methane
from the undetected methyl-hydride intermediate,
CpꢀMoI2 [12]. An asymmetric permethylmolybdenocene
2
derivative, namely the carbonyl–methyl compound

J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
2945
a substantially smaller activation barrier (DGꢀ = 27.9 kcal
molꢁ1 at 80 ꢁC) than that for the tungsten counterpart,
[Me2Si(C5Me4)2]W(Ph)H (DGꢀ = 40.1 kcal molꢁ1 at 182 ꢁC)
[9d]. If reductive elimination of methane from
Cpꢀ2MoðMeÞH and Cpꢀ2WðMeÞH were to exhibit a similar
difference in activation barrier to that for reductive elimi-
nation of benzene from [Me2Si(C5Me4)2]Mo(Ph)H and
[Me2Si(C5Me4)2]W(Ph)H (DDGꢀ ꢂ 12 kcal molꢁ1), the
barrier for reductive elimination of methane from
Cpꢀ2MoðMeÞH is estimated to be DGꢀ ꢂ 17 kcal molꢁ1
.
This activation barrier corresponds to a half-life of ꢂ7 s
at 0 ꢁC, a value that is in accord with our inability to
observe Cpꢀ2MoðMeÞH.
The dihydride Cpꢀ2MoH2 also provides a means to syn-
thesize a series of phenylchalcogenolate–hydride complexes
Cpꢀ2MoðEPhÞH (E = S, Se, Te)5 and chalcogenido com-
plexes, namely Cp2ꢀMoðg2-E2Þ (E = S, Se, Te)6 and
Cpꢀ2Moðg2-E4Þ (E = S, Se), as illustrated in Scheme 4. Thus,
Cpꢀ2MoðEPhÞH is obtained via reaction of Cp2ꢀMoH2 with
Ph2E2, while Cpꢀ2Moðg2-E2Þ and Cp2ꢀMoðg2-E4Þ are
obtained by reaction of Cpꢀ2MoH2 with 2 and 4 equivalents
of the elemental chalcogen, respectively. The moleꢀcular
structures of Cp2ꢀMoðg2-E2Þ (E = S, Se, Te) and Cp2Mo-
ðg2-Se4Þ have been determined by X-ray diffraction, as illus-
trated in Figs. 8–11.
ꢀ
˚
Fig. 5. Molecular structure of Cp2MoðCOÞ. Selected bond lengths (A)
and angles (ꢁ): Mo–C(1) 1.954(2), C(1)–O(1) 1.154(3); Mo–C(1)–O(1)
179.5(3).
Although Cpꢀ2MoðEPhÞH have not been structurally
characterized by X-ray diffraction, low-temperature 1H
NMR spectroscopic studies demonstrate that the com-
plexes exist as two conformers that are distinguished
according to whether the phenyl group occupies an endo
or exo position relative to the hydride ligand (Fig. 12).
NOESY studies enable the two isomers to be identified
by virtue of the fact that the endo isomer exhibits a cross
peak between the molybdenum-hydride and the ortho
hydrogen atoms of the phenyl group, whereas a corre-
sponding cross peak does not exist for the exo isomer.7
Measurement of the equilibrium constant as a function of
temperature demonstrates that the exo isomer is identified
as the more stable. The existence of endo and exo isomers is
not unprecedented, as illustrated by the fact that X-ray dif-
fraction studies demonstrate that the EPh ligands of
t
t
ðCpBu Þ2MoðEPhÞH (E = Se, Te) and ðCpBu Þ2MoðSPhÞ2
exhibit endo and exo conformations, respectively [7a,16].
The exo conformation is the geometry that minimizes (i)
destabilizing interactions between the lone pairs of elec-
trons on the chalcogen and the d2 pair of electrons on
the molybdenum and (ii) steric interactions between the
phenyl group and the other substituent on molybdenum,
while the endo conformation is the geometry which
Fig. 6. Molecular structure of Cpꢀ2MoO (only one of the two crystallo-
graphically independent molecules shown). Selected bond lengths (A):
˚
Mo(1)–O(1) 1.723(2), Mo(2)–O(2) 1.720(2).
Cpꢀ2MoðMeÞH. The inability to isolate the methyl-hydride
Cpꢀ2MoðMeÞH in this system is in marked contrast to the
isolation of the tungsten analogue, Cpꢀ2WðMeÞH [14,15],
but is not surprising in view of the fact that elimination
of RH from a {[M](R)(H)} complex is typically more facile
for molybdenum than for tungsten. For example, reductive
elimination of benzene from [Me2Si(C5Me4)2]Mo(Ph)H has
t
5
The counterparts ðCpBu Þ2MoðEPhÞH have also been synthesized. See
Ref. [7a].
6
t
The counterparts ðCpBu Þ2Moðg2-E2Þ have also been synthesized. See
Ref. [7a].
7
It is also noteworthy that the hydride ligand of the exo isomers of
Cpꢀ2MoðEPhÞH (E = Se, Te) exhibit coupling to selenium and tellurium at
low temperature (230 K): JSe–H = 26 Hz and JTe–H = 79 Hz.

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J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
Scheme 3.
Scheme 4.
Scheme 5.
minimizes steric interactions between the phenyl and cyclo-
pentadienyl ligands.
The interconversion between the endo and exo conform-
ers of Cpꢀ2MoðEPhÞH is facile on the NMR timescale, as
illustrated in Fig. 13 for Cpꢀ2MoðSPhÞH. Analysis of the
data demonstrates that the barrier decreases in the
sequence S > Se > Te (Table 1). In principle, the intercon-
version of the endo and exo conformers may be achieved
by either rotation of the phenyl group about the Mo–E
bond or by inversion at the chalcogen. However, the obser-
vation that the barrier decreases in the sequence
Fig. 7. Molecular structure of Cpꢀ2MoðHÞI (the hydride ligand is
˚
disordered and only one position is shown). Selected bond lengths (A):
Mo–I 2.8100(5).

J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
2947
Fig. 10. Molecular structure of Cpꢀ2Moðg2-Te2Þ. Selected bond lengths
0
0
˚
(A) and angles (ꢁ): Mo–Te 2.804(1), Te–Te 2.696(1); Te–Mo–Te 57.48(3).
ꢀ
2
˚
Fig. 8. Molecular structure of Cp2Moðg -S2Þ. Selected bond lengths (A)
and angles (ꢁ): Mo–S 2.434(1), S–S0 2.091(2); S–Mo–S0 50.88(5).
ꢀ
2
˚
Fig. 11. Molecular structure of Cp2Moðg -Se4Þ. Selected bond lengths (A)
and angles (ꢁ): Mo–Se(1) 2.527(1), Mo–Se(4) 2.550(1), Se(1)–Se(2)
2.409(1), Se(2)–Se(3) 2.307(1), Se(3)–Se(4) 2.380(1); Se(1)–Mo–Se(4)
90.30(2).
Cpꢀ2MoðEPhÞH pertains to rotation about the Mo–E bond,
½CpBu MoðPhEMeÞHꢃþ to become equivalent requires
inversion at the chalcogen and the barrier for this process
varies in the opposite sequence, i.e., S < Se < Te [7a].
t
the fluxional process that causes the two CpBu ligands of
ꢀ
2
˚
Fig. 9. Molecular structure of Cp2Moðg -Se2Þ. Selected bond lengths (A)
and angles (ꢁ): Mo–Se 2.590(1), Se–Se0 2.335(1); Se–Mo–Se0 53.59(2).
t
S > Se > Te suggests that the mechanism for interconver-
sion merely corresponds to rotation about the Mo–E bond.
Specifically, the barrier for rotation about the Mo–E bond
should be reduced as the Mo–E bond length increases
because this would reduce the interaction between the phe-
nyl group and the Cp* ligand in the transition state. In fur-
ther support of the notion that the fluxionality within
2.3. Reactivity of Cpꢀ2MoO
The oxo complex Cpꢀ2MoO is also a useful precursor for
other derivatives via reactions with Me3SiX reagents. For
example, CpꢀMoO reacts with (i) Me3SiCN to give
2

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J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
Fig. 12. Endo and exo conformers of Cpꢀ2MoðEPhÞH.
Scheme 6.
Fig. 13. Variable temperature 1H NMR spectra of Cp2ꢀMoðSPhÞH (Cp*
and hydride region).
Fig. 14. Molecular structure of Cpꢀ2MoðNCSÞ2 (the NCS ligands are
disordered and only one configuration is shown). Selected bond lengths
CpꢀMoðOSiMe3ÞCN and (ii) Me3SiX (X = NCS, N3) to
˚
(A): Mo–N(1) 2.107(2), N(1)–C(1) 1.153(2), C(1)–S(1) 1.631(2).
2
give Cpꢀ2MoX2 [17], as illustrated in Scheme 6; precedents
cyanate). 13C NMR spectroscopy has been used to distin-
guish the two coordination modes, with the chemical shift
for M–NCS moieties being comparable to, or greater than,
that for NCSꢁ (ca. 134 ppm), whereas M–SCN moieties are
for these transformations are provided by the reactions of
t
ðCpBu Þ MoO with Me3SiX [7a]. Thiocyanate is an ambiden-
2
tate ligand and may coordinate to a metal center via either
sulfur (M–SCN, thiocyanate) or nitrogen (M–NCS, isothio-
Table 1
Thermodynamic quantities pertaining to interconversion of endo and exo Cpꢀ2MoðEPhÞH
Cpꢀ2MoðSPhÞH
Cpꢀ2MoðSePhÞH
Cpꢀ2MoðTePhÞH
ꢁ2.21(9)
ꢁ5.2(4)
12.2(7)
0(3)
DHendo!exo/kcal molꢁ1
DSendo!exo/e.u.
ꢁ1.64(6)
ꢁ5.2(2)
17.6(7)
3(2)
ꢁ2.19(5)
ꢁ5.5(2)
14.2(6)
ꢁ2(2)
DHzendo!exo/kcal molꢁ1
DSzendo!exo/e.u.
DGendo!exo/kcal molꢁ1 (25 ꢁC)
DGzendo!exo/kcal molꢁ1 (25 ꢁC)
ꢁ0.09
ꢁ0.55
14.8
ꢁ0.66
16.7
12.2

J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
2949
characterized by chemical shifts less than that for NCSꢁ
mixture and the residue was dried in vacuo overnight. The
residue was extracted into pentane (200 mL), concentrated
to 100 mL, and treated with CHCl3 (5 mL). The mixture
was stirred overnight at room temperature and the resulting
precipitate was isolated by filtration, washed with pentane
(2 · 30 mL), and dried in vacuo to give Cpꢀ2MoCl2 as a
brown8 solid (4.13 g, 64%). Anal. Calc. for C20H30Cl2Mo:
C, 54.9; H, 6.9. Found: C, 54.3; H, 7.2%. IR data (KBr disk,
cmꢁ1): 2959 (s), 2904 (vs), 1456 (vs), 1374 (vs), 1069 (m),
ꢁ
(i.e., dM–SCN < dNCS 6 dM–NCS
)
[18]. On this basis,
Cpꢀ2MoðNCSÞ2, with a chemical shift of 147.4 ppm, is
clearly identified as a N-bound isothiocyanate derivative.
X-ray diffraction studies also support this coordination
mode (Fig. 14), although the NCS ligands are disordered
over two positions.
3. Conclusions
1
1019 (vs), 804 (w), 679 (w), 609 (w), 415 (w). H NMR
In summary, convenient access to permethylmolybdeno-
cene compounds is provided via the synthesis of Cpꢀ2MoCl2
which involves the reaction of MoCl5 with a mixture of
Cp*K and NaBH4 followed by treatment with CHCl3.
Cpꢀ2MoCl2 provides access to a large variety of other deriv-
atives, such as Cpꢀ2MoH2; Cpꢀ2MoMe2; Cp2ꢀMoCO; Cpꢀ2-
MoO; Cpꢀ2MoðMeÞCl; Cp2ꢀMoðHÞI; Cpꢀ2MoðEPhÞH (E =
S, Se, Te), Cp2ꢀMoðg2-E2Þ (E = S, Se, Te), Cp2ꢀMoðg2-E4Þ
(E = S, Se), Cpꢀ2MoðOSiMeÞ3CN; Cp2ꢀMoðNCSÞ2, and
Cpꢀ2MoðNÞ3, many of which have been structurally charac-
terized by X-ray diffraction.
(C6D6): 1.46 [s, C5(CH3)5]. 13C NMR (C6D6): 11.3 [q,
JC–H = 128, C5(CH3)5], 108.9 [s, C5(CH3)5]. ðCpMe EtÞ2
1
4
MoCl2 was prepared by an analogous procedure. IR data
(KBr disc, cmꢁ1): 2963 (vs), 2905 (vs), 1636 (m), 1457
(vs), 1376 (vs),1022 (vs), 970 (m). H NMR (C6D6): 0.92
1
3
[t, JH–H = 8, 6H, 2C5(CH3)4CH2CH3], 1.52 [s, 12H,
2C5(CH3)4CH2CH3], 1.54 [s, 12H, 2C5(CH3)4CH2CH3],
3
1.78 [q, JH–H = 8, 4H, 2C5(CH3)4CH2CH3]. 13C NMR
1
(C6D6): 11.3 [q, JC–H = 128, 4C, 2C5(CH3)4CH2CH3],
1
11.8 [q, JC–H = 128, 4C, 2C5(CH3)4CH2CH3], 14.3 [q,
1
1JC–H = 127, 2C, 2C5(CH3)4CH2CH3], 19.3 [t, JC–H
=
128, 2C, 2C5(CH3)4CH2CH3], 107.7 [s, 4C, 2 C5(CH3)4-
CH2CH3], 111.3 [s, 4C, 2 C5(CH3)4CH2CH3], 111.6 [s, 2C,
2C5(CH3)4CH2CH3].
4. Experimental
4.1. General considerations
4.3. Synthesis of Cpꢀ2MoH2
All manipulations were performed using a combination
of glovebox and Schlenk techniques [19]. Solvents were
purified and degassed by standard procedures. All com-
mercially available reagents were used as received without
any further purification. IR spectra were recorded as KBr
pellets on a Perkin–Elmer Paragon 1000 FT-IR spectrom-
eter and are reported in cmꢁ1. Carbon, hydrogen and
nitrogen elemental analyses were performed on a Perkin–
Elmer 2400 CHN Elemental Analyzer. NMR spectra were
recorded on Bruker Avance DPX 300, DRX 300, and
A stirred suspension of Cpꢀ2MoCl2 (1.00 g, 2.29 mmol)
in ether (30 mL) was treated with LiAlH4 (14 mL, 1.0 M
solution in ether) at ꢁ78 ꢁC and then allowed to warm
slowly to room temperature and stirred overnight. After
this period, the mixture was cooled to 0 ꢁC and treated
dropwise with degassed water (2 mL). The mixture was
allowed to warm to room temperature and stirred for
1 h. The volatile components were removed in vacuo, and
the residue was extracted into pentane. The filtrate was
concentrated to ca. 2 mL and cooled to ꢁ78 ꢁC, thereby
depositing Cpꢀ2MoH2 as a green-brown solid9 which was
isolated by filtration and dried in vacuo (0.52 g, 62%).
Anal. Calc. for C20H32Mo: C, 65.2; H, 8.8. Found: C,
65.3; H, 9.2%. IR data (KBr disk, cmꢁ1): 2975 (vs), 2898
(vs), 2712 (m), 1864 (s) [m(Mo–H)], 1478 (s), 1452 (s),
1426 (s), 1375 (vs), 1069 (m), 1028 (vs), 908 (w), 884 (w),
792 (w), 670 (w), 590 (w), 414 (w). 1H NMR (C6D6):
ꢁ8.35 [s, MoH2], 1.85 [s, C5(CH3)5]. 13C NMR (C6D6):
1
DMX 500 spectrometers. H and 13C resonance chemical
shifts are reported in ppm relative to SiMe4 (d 0) and were
referenced internally to the residual protio resonance (d
7.15 for C6D5H and 7.26 for CHCl3) and the 13C resonance
(d 128.0 for C6D6 and 77.0 for CDCl3) of the solvent. 77Se
chemical shifts are reported in ppm relative to neat Me2Se
(d = 0) and were referenced using a solution of Ph2Se2 in
C6D6 (d = 460) as external standard [20]. 125Te chemical
shifts are reported in ppm relative to neat Me2Te (d = 0)
and were referenced using a solution of Ph2Te2 in CDCl3
(d = 420.8) as external standard [21].
1
12.2 [q, JC–H = 126, C5(CH3)5], 92.9 [s, C5(CH3)5].
4.4. Synthesis of Cpꢀ2Mo(CO)
4.2. Synthesis of Cpꢀ2MoCl2 and (CpMe Et)2MoCl2
4
A mixture of Cpꢀ2MoCl2 (500 mg, 1.14 mmol), Na
(55 mg, 2.39 mmol) and Hg (2 mL) in THF (100 mL) was
A solution of MoCl5 (4.02 g, 14.7 mmol) in toluene
(10 mL)/THF (50 mL) at ꢁ78 ꢁC was slowly added to a
mixture of Cp*K (15.70 g, 90.1 mmol) and NaBH4 (1.49 g,
39.4 mmol) in THF (150 mL) at ꢁ78 ꢁC. The resulting mix-
ture was allowed to warm to room temperature and stirred
for 3 h. After this period, the mixture was heated for 24 h at
65 ꢁC. The volatile components were removed from the
8
It should be noted that the brown color of Cpꢀ2MoCl2 is in marked
contrast to the bright blue color that was reported previously (Ref. [11]).
9
Sublimation of the green-brown solid gives Cpꢀ2MoH2 as a yellow solid
upon sublimation (C. Limberg, S. Roggan and C. Jankowski, unpublished
results).

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J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
stirred under CO (1 atm) overnight at room temperature.
After this period, the volatile components were removed
and the residue was extracted into pentane. The extract
was concentrated to ca. 2 mL and cooled to ꢁ78 ꢁC,
thereby depositing Cpꢀ2MoðCOÞ as a green solid which
was isolated by filtration and dried in vacuo (290 mg,
64%). Anal. Calc. for C21H30OMo: C, 64.0; H, 7.7. Found:
C, 63.0; H, 7.8%. IR data (KBr disk, cmꢁ1): 2972 (m), 2952
(m), 2899 (s), 2716 (w), 1867 (vs) [m(CO)], 1458 (m), 1376
(s), 1067 (w), 1025 (m), 909 (w), 884 (w), 801 (vw), 682
(vw), 620 (vw), 590 (vw), 512 (w), 483 (vw), 404 (vw). IR
CpꢀMoCH3Cl as a brown solid (90 mg, 78%). Anal. Calc.
2
for C21H33ClMo: C, 60.5; H, 8.0. Found: C, 59.7; H,
7.9%. IR data (KBr disk, cmꢁ1): 2962 (vs), 2901 (vs),
2715 (m), 1481 (s), 1433 (s), 1374 (vs), 1262 (w), 1154
(m), 1067 (m), 1021 (vs), 954 (m), 803 (m), 696 (w), 675
1
(w), 653 (w), 611 (w), 541 (w), 469 (w). H NMR (C6D6):
ꢁ0.41 [s, Mo(CH3)], 1.44 [s, C5(CH3)5]. 13C NMR
1
1
(C6D6): 4.6 [q, JC–H = 129, Mo(CH3)], 10.6 [q, JC–H
127, C5(CH3)5], 102.3 [s, C5(CH3)5].
=
4.8. Reaction of Cpꢀ2Mo(CH3)Cl with LiAlH4
1
data (pentane): 1890 [m(CO)]. H NMR (C6D6): 1.72 [s,
C5(CH3)5]. 13C NMR (C6D6): 11.7 [q, JC–H = 127,
A solution of Cpꢀ2MoðMeÞCl (ca. 10 mg) in benzene-d6
was treated with LiAlH4 and monitored by 1H NMR spec-
troscopy, thereby demonstrating the formation of
Cp*(g5,g1-C5Me4CH2)MoH inter alia by comparison with
1
C5(CH3)5], 90.5 [s, C5(CH3)5], 254.8 [s, CO].
4.5. Synthesis of Cpꢀ2Mo(H)(I)
1
the H NMR spectrum of a sample prepared by the litera-
A solution of Cpꢀ2MoH2 (200 mg, 0.54 mmol) in toluene
(10 mL) was treated with CH3I (200 mg, 1.41 mmol) for 2
days at room temperature. After this period, the volatile
components were removed, and the residue was washed
with pentane (1 mL) and dried in vacuo to give
Cpꢀ2MoðHÞðIÞ as a green solid (210 mg, 78%). Anal. Calc.
for C20H31IMo: C, 48.6; H, 6.3. Found: C, 48.4; H, 6.5%.
IR data (KBr disk, cmꢁ1): 2956 (s), 2891 (vs), 1869 (m)
[m(Mo–H)], 1462 (vs), 1373 (vs), 1159 (w), 1070 (m), 1021
(vs), 844 (w), 798 (w), 669 (w), 613 (w), 544 (vw), 412
(w). 1H NMR (C6D6): ꢁ9.49 [s, MoH], 1.75 [s,
ture method [12]. Specifically, a solution of Cpꢀ2MoH2
(200 mg, 0.54 mmol) in cyclohexane (10 mL) was photo-
lyzed for one day. After this period, the volatile compo-
nents were removed in vacuo, and the residue was
extracted into pentane and filtered. The filtrate was concen-
trated to 1 mL, cooled at ꢁ78 ꢁC, filtered and dried in
vacuo to give Cp*(g6-C5Me4CH2)MoH as a yellow-brown
solid (95 mg, 48%). Anal. Calc. for C20H30Mo: C, 65.6; H,
8.3. Found: C, 65.7; H, 8.5%. IR data (KBr disk, cmꢁ1):
2951 (vs), 2897 (vs), 2717 (m), 1858 (m) [m(Mo–H)], 1458
(s), 1374 (vs), 1160 (w), 1080 (m), 1024 (vs), 949 (w), 908
(m), 879 (m), 843 (m), 773 (w), 750 (w), 623 (m), 589 (w),
1
C5(CH3)5]. 13C NMR (C6D6): 13.1 [q, JC–H = 127,
1
4
C5(CH3)5], 99.0 [s, C5(CH3)5].
541 (vw), 425 (w). H NMR (C6D6): ꢁ9.69 [q, JH–H
=
3.5, 1H, MoH], 1.40 [s, 3H of C5(CH3)4CH2], 1.55 [s, 3H
of C5(CH3)4CH2], 1.75 [s, 15H, C5(CH3)5], 1.85 [s, 3H of
4.6. Synthesis of Cpꢀ2Mo(CH3)
2
4
C5(CH3)4CH2], 1.97 [d, JH–H = 3.5, 3H of C5(CH3)4CH2],
A mixture of Cpꢀ2MoCl2 (500 mg, 1.14 mmol) and
CH3Li (75 mg, 3.41 mmol) in toluene (20 mL) was stirred
at room temperature for 3 h. After this period, the volatile
components were removed in vacuo, and the residue was
extracted into pentane. The extract was concentrated to
ca. 2 mL and cooled to ꢁ78 ꢁC, thereby depositing
CpꢀMoðCH3Þ as a red-brown solid which was isolated
2.69 [br, 1H of C5(CH3)4CH2], 3.29 [br, 1H of
1
C5(CH3)4CH2]. 13C NMR (C6D6): 8.6 [q, JC–H = 126, 1C
1
of C5(CH3)4CH2], 9.5 [q, JC–H = 126, 1C of C5(CH3)4-
1
CH2], 11.3 [q, JC–H = 126, 1C of C5(CH3)4CH2], 11.8 [q,
1
1JC–H = 126, 5C of C5(CH3)5], 15.5 [q, JC–H = 127, 1C
1
of C5(CH3)5CH2], 49.5 [t, JC–H = 155, 1C of C5(CH3)4-
CH2], 90.3 [s, 1C of C5(CH3)4CH2], 92.8 [s, 1C of
C5(CH3)4CH2], 95.3 [s, 5C of C5(CH3)5], 97.9 [s, 1C of
C5(CH3)4CH2], 101.5 [s, 1C of C5(CH3)4CH2], 109.0 [s,
1C of C5(CH3)4CH2].
2
2
by filtration and dried in vacuo (275 mg, 61%). Anal. Calc.
for C22H36Mo: C, 66.6; H, 9.2. Found: C, 65.8; H, 9.5%. IR
data (KBr disk, cmꢁ1): 2948 (vs), 2899 (vs), 2859 (vs), 2716
(m), 1481 (s), 1425 (s), 1374 (vs), 1167 (m), 1065 (m), 1021
(vs), 800 (w), 743 (w), 612 (w), 543 (w), 468 (w), 410 (w). 1H
4.9. Synthesis of Cpꢀ2MoO
NMR (C6D6): ꢁ0.66 [s, Mo(CH3)2], 1.42 [s, C5(CH3)5]. 13
C
1
NMR (C6D6): 6.9 [q, JC–H = 125, Mo(CH3)2], 10.1 [q,
1JC–H = 126, C5(CH3)5], 96.2 [s, C5(CH3)5].
A mixture of Cpꢀ2MoCl2 (1.00 g, 2.29 mmol) and LiOH
(0.84 g, 35.08 mmol) in toluene (50 mL) was stirred at
80 ꢁC for 2 days. After this period, the volatile components
were removed in vacuo, and the residue was extracted into
pentane (50 mL). The extract was concentrated to ca. 2 mL
and cooled to ꢁ78 ꢁC, thereby depositing Cpꢀ2MoO as a
green solid which was isolated by filtration and dried in
vacuo (0.56 g, 64%). Anal. Calc. for C20H30OMo: C,
62.8; H, 7.9. Found: C, 62.6; H, 8.2%. IR data (KBr disk,
cmꢁ1): 2973 (s), 2949 (s), 2902 (vs), 2717 (w), 1478 (m),
1440 (s), 1373 (vs), 1159 (w), 1065 (m), 1024 (s), 915 (m),
4.7. Synthesis of Cpꢀ2Mo(CH3)Cl
A solution of Cpꢀ2MoðCH3Þ2 (110 mg, 0.28 mmol) in tol-
uene (10 mL) was treated with HCl (0.27 mL, 1.0 M solu-
tion in Et2O) and the mixture was stirred at room
temperature for 2 h. After this period, the volatile compo-
nents were removed in vacuo and the residue was washed
with pentane (2 mL) and dried in vacuo to give

J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
2951
885 (m), 834 (vs) [m(Mo@O)], 799 (m), 713 (vw), 682 (vw),
at 80 ꢁC for 3 h. After this period, the volatile components
were removed and the residue was extracted into THF
(50ꢀmL). The solvent was removed from the extract to give
Cp2Moðg2-Se4Þ as a red-purple solid which was washed
with toluene (2 · 20 mL) and pentane (2 · 10 mL) and
dried in vacuo (160 mg, 43%). Anal. Calc. for
C20H30Se4Mo: C, 35.2; H, 4.4. Found: C, 34.4; H, 4.6%.
IR data (KBr disk, cmꢁ1): 2985 (m), 2945 (m), 2893 (vs),
2712 (w), 1480 (vs), 1447 (vs), 1372 (vs), 1065 (m), 1017
(vs), 804 (w), 590 (w), 547 (w), 491 (w), 408 (w). 1H
NMR (CDCl3): 1.82 [s, C5(CH3)5]. 13C NMR (CDCl3):
1
621 (vw), 600 (vw), 546 (vw), 437 (w), 405 (vw). H NMR
(C6D6): 1.70 [s, C5(CH3)5]. 13C NMR (C6D6): 11.8 [q,
1JC–H = 126, C5(CH3)5], 109.2 [s, C5(CH3)5].
4.10. Synthesis of Cpꢀ2Mo(g2-S2)
A mixture of Cpꢀ2MoH2 (200 mg, 0.54 mmol) and sulfur
(35 mg, 1.09 mmol) in toluene (10 mL) was stirred at room
temperature for 2 h. After this period, the volatile compo-
nents were removed in vacuo and the residue was washed
witꢀh pentane (2 · 2 mL) and dried in vacuo to give
Cp2Moðg2-S2Þ as a red-brown solid (150 mg, 64%). Anal.
Calc. for C20H30S2Mo: C, 55.8; H, 7.0. Found: C, 55.4;
H, 7.3%. IR data (KBr disk, cmꢁ1): 2970 (s), 2946 (s),
2894 (vs), 2708 (w), 1473 (s), 1371 (vs), 1068 (m), 1019
(vs), 802 (m), 728 (w), 608 (w), 526 (m), 457 (w), 413 (w).
1H NMR (C6D6): 1.58 [s, C5(CH3)5]. 13C NMR (C6D6):
1
12.0 [q, JC–H = 128, C5(CH3)5], 106.1 [s, C5(CH3)5].
1
77Se{1H} NMR (CDCl3): 376 [s, JSe–Se = 195 (satellite),
1
2Se of Mo(g2-Se4)], 997 [s, JSe–Se = 195 (satellite), 2Se of
Mo(g2-Se4)].
4.14. Synthesis of Cpꢀ2Mo(g2-Te2)
11.3 [q, JC–H = 127, C5(CH3)5], 101.8 [s, C5(CH3)5].
A mixture of Cpꢀ2MoH2 (150 mg, 0.41 mmol) and tellu-
rium (210 mg, 1.65 mmol) in toluene (10 mL) was stirred at
120 ꢁC for 4 days. After this period, the mixture was fil-
tered and the volatile components were removed in vacuo.
The residue was washed with pentane (2 · 5 mL) and dried
in vacuo to give Cpꢀ2Moðg2-Te2Þ as a red solid (150 mg,
59%). Anal. Calc. for C20H30Te2Mo: C, 38.6; H, 4.9.
Found: C, 38.0; H, 4.8%. IR data (KBr disk, cmꢁ1): 2965
(m), 2943 (s), 2879 (vs), 1468 (s), 1372 (vs), 1262 (w),
1067 (m), 1016 (vs), 956 (w), 803 (w), 653 (w), 603 (w),
1
4.11. Synthesis of Cpꢀ2Mo(g2-S4)
A mixture of Cpꢀ2Moðg2-S2Þ (90 mg, 0.21 mmol) and
sulfur (20 mg, 0.62 mmol) in toluene (5 mL) was stirred
at 80 ꢁC for 2 days. After this period, the mixture was
cooled to room temperature ꢀ and pentane (5 mL) was
added, thereby depositing Cp2Moðg2-S4Þ as a red solid
which was isolated by filtration, washed with pentane
(2 · 5 mL) and dried in vacuo (70 mg, 68%). Anal. Calc.
for C20H30S4Mo: C, 48.6; H, 6.1. Found: C, 48.8; H,
6.4%. IR data (KBr disk, cmꢁ1): 2987 (m), 2948 (m),
2899 (vs), 2713 (w), 1483 (vs), 1449 (s), 1374 (vs), 1157
(w), 1065 (w), 1018 (vs), 802 (w), 741 (w), 678 (w), 580
(w), 528 (w), 495 (w), 462 (w), 434 (w), 408 (vw). 1H
NMR (CDCl3): 1.74 [s, C5(CH3)5]. 13C NMR (CDCl3):
1
539 (w), 497 (w), 469 (w), 411 (w). H NMR (C6D6): 1.88
1
[s, C5(CH3)5]. 13C NMR (C6D6): 14.5 [q, JC–H = 127,
C5(CH3)5], 99.3 [s, C5(CH3)5]. 125Te NMR (C6D6): ꢁ225
[s].
4.15. Synthesis of [Cpꢀ2Mo(CO)CH3]I
11.2 [q, JC–H = 128, C5(CH3)5], 107.2 [s, C5(CH3)5].
A solution of Cpꢀ2MoðCOÞ (70 mg, 0.18 mmol) in tolu-
ene (10 mL) was treated with CH3I (200 mg, 1.41 mmol)
and the mixture was stirred for 1 h at room temperature.
After this period, the mixture was filtered and the precipi-
tate was washed with toluene (5 mL) and pentane
1
4.12. Synthesis of Cpꢀ2Mo(g2-Se2)
A mixture of Cpꢀ2MoH2 (200 mg, 0.54 mmol) and sele-
nium (85 mg, 1.08 mmol) in toluene (10 mL) was stirred
at 80 ꢁC for 2 h. After this period, the mixture was filtered
and the volatile components were removed in vacuo. The
residue was washed with pentane (2 · 5 mL) and dried in
vacuo to give Cpꢀ2Moðg2-Se2Þ as a green solid (210 mg,
74%). Anal. Calc. for C20H30Se2Mo: C, 45.8; H, 5.8.
Found: C, 45.9; H, 6.1%. IR data (KBr disk, cmꢁ1): 2968
(m), 2888 (vs), 2707 (w), 1471 (s), 1370 (vs), 1161 (w),
1067 (m), 1017 (vs), 804 (m), 696 (w), 601 (w), 543 (w),
(2 · 5 mL) and dried in vacuo to give ½CpꢀMoðCOÞCH3ꢃI
2
as
a brown solid (50 mg, 53%). Anal. Calc. for
C22H33OIMo: C, 49.3; H, 6.2. Found: C, 50.2; H, 6.4%.
IR data (KBr disk, cmꢁ1): 2985 (w), 2954 (w), 2904 (w),
1946 (vs) [m(CO)], 1493 (w), 1468 (m), 1428 (w), 1386 (m),
1184 (vw), 1075 (vw), 1024 (m), 514 (w), 494 (w), 433
1
(vw), 410 (vw). H NMR (CDCl3): ꢁ0.62 [s, Mo(CH3)],
1
1.86 [s, C5(CH3)5]. 13C NMR (CDCl3): ꢁ1.6 [q, JC–H
=
1
133, Mo(CH3)], 10.6 [q, JC–H = 129, C5(CH3)5], 105.2 [s,
C5(CH3)5], 234.0 [s, CO].
1
411 (w). H NMR (CDCl3): 1.82 [s, C5(CH3)5]. 13C NMR
1
(CDCl3): 12.1 [q, JC–H = 128, C5(CH3)5], 101.4 [s,
C5(CH3)5]. 77Se{1H} NMR (CDCl3): 73 [s].
4.13. Synthesis of Cpꢀ2Mo(g2-Se4)
4.16. Synthesis of Cpꢀ2Mo(OSiMe3)CN
A solution of Cpꢀ2MoO (100 mg, 0.26 mmol) in toluene
(10 mL) was treated with Me3SiCN (100 mg, 1.01 mmol)
for 1 h at room temperature. After this period, the volatile
components were removed and the residue was washed with
A mixture of Cpꢀ2MoH2 (200 mg, 0.54 mmol) and sele-
nium (175 mg, 2.22 mmol) in toluene (20 mL) was stirred

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J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
pentane (5 mL) and dried in vacuo to give
3JH–H = 8, 2H of SC6H5] (2H of SC6H5 not located). 13C
1
CpꢀMoðOSiMe3ÞCN as a red-brown solid (90 mg, 71%).
NMR (C6D6), both isomers: 11.2 [q, JC–H = 127,
2
1
Anal. Calc. for C24H39NOSiMo: C, 59.9; H, 8.2; N, 2.9.
Found: C, 59.9; H, 8.5; N, 2.8%. IR data (KBr disk,
cmꢁ1): 2961 (m), 2942 (m), 2905 (s), 2098 (s) [m(C„N)],
1461 (m), 1378 (m), 1251 (m), 1235 (s), 1074 (w), 1025 (s),
C5(CH3)5], 11.6 [q, JC–H = 127, C5(CH3)5], 99.5 [s,
1
C5(CH3)5], 99.6 [s, C5(CH3)5], 120.6 [d, JC–H = 156,
1
1
SC6H5], 120.9 [d, JC–H = 158, SC6H5], 126.9 [d, JC–H
=
1
155, SC6H5], 127.6 [d, JC–H = 155, 2SC6H5], 132.3 [d,
1
1
965 (vs), 821 (s), 745 (m), 650 (w), 447 (w), 410 (w). H
1JC–H = 158, SC6H5], 132.7 [d, JC–H = 157, SC6H5],
NMR (C6D6): 0.51 [s, OSi(CH3)3], 1.49 [s, C5(CH3)5]. 13C
150.0 [s, SC6H5], 151.0 [s, SC6H5].
1
NMR (C6D6): 8.4 [q, JC–H = 116, OSi(CH3)3], 11.5 [q,
1JC–H = 128, C5(CH3)5], 107.8 [s, C5(CH3)5], 153.4 [s, CN].
4.17. Synthesis of Cpꢀ2Mo(NCS)2
4.20. Synthesis of Cpꢀ2Mo(SePh)H
A mixture of Cpꢀ2MoH2 (200 mg, 0.54 mmol) and PhSe-
SePh (170 mg, 0.54 mmol) in toluene (10 mL) was stirred
for 2 h at room temperature. After this period, the volatile
components were removed, and the residue was washed
with pentane (2 · 5 mL) and dried in vacuo to give
A solution of Cpꢀ2MoO (100 mg, 0.26 mmol) in toluene
(10 mL) was treated with Me3SiNCS (340 mg, 2.59 mmol)
for 1 day at room temperature. After this period, the mix-
ture was filtered and the residue was washed with toluene
(5 mL) and pentane (2 · 5 mL) and dried in vacuo to give
Cpꢀ2MoðNCSÞ2 as a purple solid (65 mg, 52%). Anal. Calc.
for C22H30N2S2Mo: C, 54.8; H, 6.3; N, 5.8. Found: C, 54.8;
H, 6.7; N, 5.4%. IR data (KBr disk, cmꢁ1): 2992 (vw), 2959
(vw), 2910 (w), 2092 (vs) [m(NC)], 1477 (w), 1437 (w), 1380
1
Cpꢀ2MoðSePhÞH as a red-brown solid (210 mg, 74%). H
NMR (C6D6, 300 K): exo isomer ꢁ9.43 [br. s, 1H of
Mo–H], 1.66 [br. s, 30H, C5(CH3)5], 7.02 [br, 2H of
SeC6H5], 7.46 [br, 1H of SeC6H5], [2H of SeC6H5 not
located]; endo isomer: ꢁ7.71 [br, 1H of Mo–H], 1.66 [br,
30H, C5(CH3)5], 7.02 [br. s, 2H of SeC6H5], 7.46 [br. s,
1H of SeC6H5] 8.36 [br. s, 2H of SeC6H5]. 13C NMR
1
(m), 1070 (vw), 1017 (m), 829 (m), 734 (vw), 427 (vw). H
NMR (CDCl3): 1.82 [s, C5(CH3)5]. 13C NMR (CDCl3):
(C6D6): 11.9 [q, JC–H = 127, C5(CH3)5], 98.8 [s,
1
1
1
10.9 [q, JC–H = 129, C5(CH3)5], 112.2 [s, C5(CH3)5],
C5(CH3)5], 122.1 [br. d, JC–H = 159, 1C of SeC6H5],
1
147.4 [s, Mo(NCS)2].
127.3 [br. d, JC–H = 154, 2C of SeC6H5], 134.4 [br. d,
1JC–H = 157, 2C of SeC6H5], 139.9 [br. s, 1C of SeC6H5].
4.18. Synthesis of Cpꢀ2Mo(N3)2
77Se{1H} NMR (C6D6): 179 [s], 217 [s] (3:1).
A solution of Cpꢀ2MoO (220 mg, 0.58 mmol) in toluene
(20 mL) was treated with Me3SiN3 (220 mg, 1.91 mmol)
for 2 h at room temperature. After this period, the volatile
components were removed, and the residue was washed
with pentane (3 · 2 mL) and dried in vacuo to give
Cpꢀ2MoðN3Þ2 as a green solid (190 mg, 73%) [Caution: cer-
tain azide compounds may decompose explosively]. Anal.
Calc. for C20H30N6Mo: C, 53.3; H, 6.7; N, 18.7. Found:
C, 52.5; H, 6.5; N, 18.0%. IR data (KBr disk, cmꢁ1):
2992 (vw), 2960 (vw), 2911 (w), 2040 (vs) [m(N3)], 1486
(w), 1458 (w), 1380 (m), 1337 (w), 1285 (w), 1068 (vw),
1021 (w), 804 (vw), 644 (vw), 601 (vw), 420 (vw). 1H
NMR (C6D6): 1.45 [s, C5(CH3)5]. 13C NMR (C6D6): 9.9
4.21. Synthesis of Cpꢀ2Mo(TePh)H
A mixture of Cpꢀ2MoH2 (150 mg, 0.41 mmol) and PhTe-
TePh (170 mg, 0.42 mmol) in toluene (10 mL) was stirred
for 1 h at room temperature. After this period, the volatile
components were removed, and the residue was washed
with pentane (2 · 3 mL) and dried in vacuo to give
Cpꢀ2MoðTePhÞH as a brown solid (160 mg, 69%). 1H
NMR (C6D6, 300 K): ꢁ9.4 [br, Mo–H], 1.75 [s, 30H,
3
C5(CH3)5], 6.96 [t, JH–H = 7, 2H of TeC6H5], 7.07 [t,
3JH–H = 7, 1H of TeC6H5], 7.83 [br, 2H of TeC6H5]. 13C
1
NMR (C6D6): 12.8 [q, JC–H = 127, C5(CH3)5], 97.5 [s,
1
C5(CH3)5], 112.5 [br, 1C of TeC6H5], 123.8 [dt, JC–H
=
1
2
1
[q, JC–H = 128, C5(CH3)5], 110.1 [s, C5(CH3)5].
159, JC–H = 7, 1C of TeC6H5], 127.6 [dd, JC–H = 156,
2JC–H = 8, 2C of TeC6H5], 138.6 [dt, JC–H = 159, JC–H
=
1
2
4.19. Synthesis of Cpꢀ2Mo(SPh)H
7, 2C of TeC6H5]. 125Te{1H} NMR (C6D6): 416 [s].
A mixture of Cpꢀ2MoH2 (150 mg, 0.41 mmol) and
PhSSPh (85 mg, 0.39 mmol) in toluene (10 mL) was stirred
for 1 day at 80 ꢁC. After this period, the volatile compo-
nents were removed and the residue was washed with cold
pentane (3 mL) and dried in vacuo to give Cpꢀ2MoðSPhÞH
4.22. X-ray structure determinations
Single-crystal X-ray diffraction data were collected on a
Bruker P4 diffractometer equipped with a SMART CCD
detector and crystal data, data collection and refinement
parameters are summarized in Table 2. The structures were
solved using direct methods and standard difference map
techniques, and were refined by full-matrix least-squares
procedures on F2 with SHELXTL (Version 5.10) [22]. The
crystallographic data for Cpꢀ2MoCl2 (CCDC #289487),
1
as a brown solid (110 mg, 57%). H NMR (C6D6, 300 K):
exo isomer ꢁ9.23 [s, 1H of Mo–H], 1.62 [s, 30H,
3
C5(CH3)5], 6.92 [t, JH–H = 7, 1H of SC6H5], 7.09 [t,
3
3JH–H = 8, 2H of SC6H5], 8.24 [d, JH–H = 8, 2H of
SC6H5]; endo isomer ꢁ7.52 [s, 1H of Mo–H], 1.64 [s,
3
ðCpMe EtÞ MoCl2 (CCDC #289486), Cp2ꢀMoH2 (CCDC
4
30H, C5(CH3)5], 6.97 [t, JH–H = 7, 1H of SC6H5], 7.22 [t,
2

J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
2953
Table 2
Crystal, intensity collection, and refinement data
Cpꢀ2MoCl2
ðCpMe EtÞ2MoCl2
Cpꢀ2MoH2
4
Compound
Formula
Formula weight
System
C20H30MoCl2
437.28
monoclinic
Cc
C22H34MoCl2
465.33
monoclinic
P21/n
8.406(1)
17.556(1)
14.385(1)
90
90.921(1)
90
2122.5(3)
4
C20H32Mo
368.40
monoclinic
P21/n
8.5210(6)
24.875(2)
9.7734(6)
90
114.266(1)
90
1888.5(2)
4
Space group
˚
a (A)
8.267(1)
17.913(1)
13.686(1)
90
107.020(1)
90
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
1938.0(3)
4
Z
T (K)
203
0.71073
0.950
28.3
3112
223
0.71073
0.873
28.3
4927
203
0.71073
0.688
28.3
4353
˚
Radiation (k, A)
l(Mo Ka) (mmꢁ1
h Maximum (ꢁ)
Number of data
)
Number of parameters
R1
220
236
208
0.0410
0.1029
1.118
0.0292
0.0651
1.005
0.0339
0.0713
1.040
wR2
Goodness-of-fit
Cpꢀ2MoMe2
Cpꢀ2MoO
Cpꢀ2MoCO
Formula
Formula weight
System
C
22H36Mo
C20H30MoO
382.38
monoclinic
P21/n
12.922(1)
18.951(1)
16.096(1)
90
108.912(1)
90
3728.8
8
C21H30MoO
394.39
monoclinic
P21/c
8.539(1)
24.943(2)
9.929(1)
90
114.082(1)
90
1930.7(2)
4
396.45
monoclinic
Cc
Space group
˚
a (A)
8.4126(6)
18.360(1)
13.239(1)
90
106.793(1)
90
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
1957.7(2)
4
Z
T (K)
203
0.71073
0.669
28.3
3951
203
0.71073
0.704
28.3
8612
213
0.71073
0.682
28.3
4444
˚
Radiation (k, A)
l(Mo Ka) (mmꢁ1
h Maximum (ꢁ)
Number of data
)
Number of parameters
R1
244
417
218
0.0191
0.0477
1.043
0.0309
0.0757
1.029
0.0258
0.0598
1.100
wR2
Goodness-of-fit
Cpꢀ2MoðHÞI
Cpꢀ2MoðNCSÞ2
Cpꢀ2Moðg2-S2Þ
Formula
Formula weight
System
C
20H31MoI
C22H30MoN2S2
482.54
monoclinic
C2/c
17.584(1)
9.399(1)
15.588(1)
90
118.004(1)
90
2274.6(3)
4
C20H30MoS2
430.50
orthorhombic
Fdd2
17.187(1)
26.657(2)
8.688(1)
90
90
90
3980.1(5)
8
494.29
monoclinic
P21/n
8.564(1)
14.040(1)
17.121(1)
90
102.872(1)
90
2006.9(2)
4
Space group
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
T (K)
213
0.71073
2.188
28.4
4637
223
0.71073
0.769
28.3
2633
213
0.71073
0.867
28.3
2299
112
˚
Radiation (k, A)
l(Mo Ka) (mmꢁ1
h Maximum (ꢁ)
Number of data
)
Number of parameters
217
161
(continued on next page)

2954
J.H. Shin et al. / Inorganica Chimica Acta 359 (2006) 2942–2955
Table 2 (continued)
Compound
Cpꢀ2MoðHÞI
Cpꢀ2MoðNCSÞ2
Cpꢀ2Moðg2-S2Þ
R1
wR2
0.0405
0.0768
1.017
0.0510
0.1264
1.062
0.0199
0.0481
1.071
Goodness-of-fit
Cpꢀ2Moðg2-Se2Þ
Cpꢀ2Moðg2-Te2Þ
Cpꢀ2Moðg2-Se4Þ
Formula
Formula weight
System
C
20H30MoSe2
C20H30MoTe2
621.58
orthorhombic
Fdd2
16.754(8)
27.241(12)
9.146(5)
90
90
90
4175(3)
8
C20H30MoSe4
682.22
monoclinic
P21/n
10.675(1)
14.658(1)
13.963(1)
90
92.642(1)
90
2182.5(1)
4
524.30
orthorhombic
Fdd2
16.887(1)
26.771(2)
8.872(1)
90
90
90
4010.9(5)
8
Space group
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
T (K)
203
203
0.71073
3.367
28.2
2341
223
0.71073
7.274
28.3
5047
˚
Radiation (k, A)
0.71073
4.282
28.3
l(Mo Ka) (mmꢁ1
h Maximum (ꢁ)
Number of data
)
1718
Number of parameters
R1
112
111
236
0.0194
0.0510
1.107
0.0198
0.0499
1.042
0.0304
0.0792
1.050
wR2
Goodness-of-fit
#289480), Cpꢀ2MoMe2 (CCDC #289481), Cpꢀ2MoðCOÞ
(CCDC #289478), Cp2ꢀMoO (CCDC #289489), Cpꢀ2Mo-
ðHÞI (CCDC #289488), Cpꢀ2Moðg2-S2Þ (CCDC #289485),
Cp2ꢀMoðg2-Se2Þ (CCDC #289484), Cp2ꢀMoðg2-Te2Þ (CCDC
#289483), Cpꢀ2Moðg2-Se4Þ (CCDC #289482), and Cpꢀ2Mo-
ðNCSÞ2 (CCDC #289479) have been deposited with the
Cambridge Crystallographic Data Centre.
(d) N.D. Silavwe, M.P. Castellani, D.R. Tyler, Inorg. Synth. 29
(1992) 204;
(e) M.L.H. Green, C.N. Street, G. Wilkinson, Z. Naturforsch. B 14
(1959) 738;
(f) F.A. Cotton, G. Wilkinson, Z. Naturforsch. B 9 (1954) 417;
(g) E.O. Fischer, Y. Hristidu, Z. Naturforsch. B 15 (1960) 135.
[4] (a) R. Davis, L.A.P. Kane-Maguire, in: G. Wilkinson, F.G.A.
Stone, E.W. Abel (Eds.), Comprehensive Organometallic Chemis-
try, vol. 3, Pergamon Press, New York, 1982, pp. 1321–1384
(Chapter 28);
Acknowledgment
(b) M.J. Morris, in: J.A. Labinger, M.J. Winter (Eds.), Compre-
hensive Organometallic Chemistry II, vol. 5, Pergamon Press, New
York, 1995 (Chapter 5).
We thank the US Department of Energy, Office of Basic
Energy Sciences (DE-FG02-93ER14339) for support of
this research.
[5] J.A. McCleverty, in: E.R. Braithwaite, J. Haber (Eds.), Molybdenum:
An Outline of Its Chemistry and Uses, Elsevier, Amsterdam, 1994,
pp. 343–350 (Chapter 6) and references therein.
[6] See, for example: L. Luo, G. Lanza, I.L. Fragala, C.L. Stern, T.J.
Marks, J. Am. Chem. Soc. 120 (1998) 3111.
[7] (a) J.H. Shin, W. Savage, V.J. Murphy, J.B. Bonanno, D.G.
Churchill, G. Parkin, J. Chem. Soc., Dalton Trans. (2001)
1732;
Supplementary data
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.ica.2005.
12.037.
(b) D.G. Churchill, J.H. Shin, G. Parkin, J. Chem. Crystallogr. 33
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[8] (a) M.G.B. Drew, V. Felix, C.C. Romao, B. Royo, J. Chem. Soc.,
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(b) J.R. Ascenso, C.G. de Azevedo, I.S. Goncalves, E. Herdtweck,
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