New insights into the reactivity of the tantalocene hydride Cp2′TaH3 (Cp′ = Η5-tBuC5H4). Synthesis and characterisation of cationic Ta(V) complexes with 0,0 and S,N chelating ligands

Article abstract of DOI:10.1016/S0022-328X(02)01577-2

Reaction of various neutral L-XH bidentate ligands (2-aminobenzo?c acid, acetylacetone, dibenzoylmethan and 2-aminobenzenethiol) with [Cp₂^′TaH₂]⁺, obtained in situ from Cp₂^′TaH₃

Full text of DOI:10.1016/S0022-328X(02)01577-2

Journal of Organometallic Chemistry 656 (2002) 139ꢂ145
/
www.elsevier.com/locate/jorganchem
?
New insights into the reactivity of the tantalocene hydride Cp2TaH3
(Cp?ꢀ
/
h5-tBuC5H4). Synthesis and characterisation of cationic Ta(V)
complexes with 0,0 and S,N chelating ligands
Olivier Blacque, Marek M. Kubicki, Jean-Claude Leblanc *, Andre´ Sadorge,
Philippe Sauvageot, Claude Moıse
¨
Laboratoire de Synthe`se et d’Electrosynthe`se Organome´talliques (UMR 5632), Universite´ de Bourgogne, F-21100 Dijon, France
Received 19 March 2002; accepted 6 May 2002
Abstract
Reaction of various neutral LÃ
/
XH bidentate ligands (2-aminobenzoıc acid, acetylacetone, dibenzoylmethan and 2-aminobenze-
?
¨
nethiol) with [Cp2TaH2] , obtained in situ from Cp2TaH3 treated with triphenylmethan cation, affords after dihydrogen
ꢁ
?
2
elimination the corresponding cationic species [Cp2Ta(H)(LÃ
/
X)]ꢁ in BF4 or PF6 salts. Complexes [Cp2TaH(h -O2CC6H4-o-NH2Ã
/
?
?
2
2
?
?
O,O?)]PF6 (3), {Cp2Ta[h -OC(Me)CHC(Me)OÃ
/
O,O?]}BF4 (4a), {Cp2TaH[h -OC(Ph)CHC(Ph)OÃ
/
O,O?]}BF4 (4b) and
S,N)]PF6 (5) are characterised by analytical and spectroscopic methods. With thiopyridine, the
2
?
[Cp2TaH(h -SC6H4-o-NH2Ã
/
2
?
kinetic (6) and the thermodynamic (6?) isomers [Cp2TaH(h -2-SC5H4NÃ
/S,N)]PF6 are identified. Crystal structures are reported for
complexes 3, 5 and 6?. # 2002 Elsevier Science B.V. All rights reserved.
Keywords: Tantalocene hydrides; Carboxylatoꢂ; Acetylacetonatoꢂ; 2-Aminobenzenethiolatoꢂ; Pyridine-2-thiolato complexes; Crystal structures
/
/
/
1. Introduction
An unconventional hydrogen bond MÃ
where the hydride atom of a transition metal behaves
as proton acceptor, has recently attracted attention.
Several examples of intramolecular hydrogen bonds of
this type involving electron rich transition metal hy-
/
Hꢀ ꢀ ꢀHÃ/X,
However, to the best of our knowledge, no report on
early-transition metal complex of this type is known.
We have recently found a new entry into the
drides (Groups 7ꢂ
(e.g. B [2] and Ga [3]) have been reported. The OÃ
NÃH bonds can act therein as usual acidic components.
These interactions, observed as well in the solid state as
in solution, can be easily broken by coordination of a
good hydrogen-bond acceptor like an oxygenated sol-
vent [1e]. In some cases, the dihydrogen molecule can be
displaced by the own complex ligand as reported for
iridium compound [1j].
/
9) [1] or main group element hydrides
?
tantalocene hydride chemistry by reaction of Cp2TaH3
/H and
(1) (Cp?ꢀ
h5-tBuC5H4) with strong electrophiles (Hꢁ
/
/
or CPh3ꢁ) or by its oxidation with ferrocenium ion that
give rise in situ to the formation of a cationic dihydride
ꢁ
complex [Cp2TaH2] (2ꢁ) [4]. Following our interest in
?
the chemistry of this cationic complex towards one and
two electron donor ligands, we consider now its
behaviour against bidentate ligands LÃ/XH such as 2-
aminobenzoıc acid, b-diketones, 2-aminothiophenol and
¨
pyridine-2-thiol. The overall reaction pathway is de-
picted below.
* Corresponding author
E-mail address: jcleblan@u-bourgogne.fr (J.-C. Leblanc).
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 5 7 7 - 2

140
O. Blacque et al. / Journal of Organometallic Chemistry 656 (2002) 139ꢂ145
/
Crystal structures of ionic Ta(V) complexes
Fig. 1. The non-coordination of the amino group at
tantalum centre is confirmed by this study.
2
?
?
[Cp2TaH(h -O2CC6H4-o-NH2Ã
(h2-SC6H4-o-NH2Ã
S,N)]PF6
SNC6H4ÃS,N)]PF6 are reported.
/
O,O?)]PF6, [Cp2TaH-
and
2
?
/
[Cp2TaH(h -2-
Consequently, one may assume that the formation of
complex 3 results from an initial co-ordination of one of
the two oxygen atoms of carboxylic group of the ligand
/
ꢁ
?
at the central site of cationic intermediate [Cp2Ta(H)2]
followed by immediate elimination of dihydrogen. The
central site at the metal corresponds to the central lobe
of empty Ta(V) a1 (in C2v symmetry) molecular orbital
(LUMO) of dihydride cation [6]. Formally, the cation in
3 may be also formed by a similar attack on one of the
external (lateral) lobes of this orbital. However, a central
co-ordination may be preferred for steric reasons.
2. Results and discussion
2.1. 2-aminobenzoıc acid
¨
The addition of Ph3C×
¨
(abaH) to a solution of Cp2TaH3 (1) promptly affords
/
PF and 2-aminobenzoıc acid
6
?
?
the formation of the carboxylato complex [Cp2Ta(H)(a-
(aba)]PF6 (3) with evolution of dihydrogen (Eq. (1)).
Complex 3 is obtained in good yield (80%) in analyti-
cally pure form.
2.2. b-diketone
When complex 1 is treated with one equivalent of
Ph3C×/BF4 in presence of an excess of acetylacetone
(acacH) or dibenzoylmethan (dbmH) for some minutes,
pale yellow solutions are obtained. Colourless crystals of
complexes 4a and 4b, respectively, are obtained by re-
ð1Þ
crystallisation from CHCl3ꢂether. The analytical and
/
spectroscopic data are consistent with the proposed
structure 4 (Eq. (2)).
In principle 3, may exhibit several isomers according
to the central or lateral position of potentially coordi-
nating atoms (O and N).
The structure proposed for compound 3 in Eq. (1) is
based on its IR spectroscopic data. The spectrum shows
two bands at 3505 and 3397 cmꢃ1 for the uncoordinated
amino group and two bands at 1627 and 1500 cmꢃ1
corresponding to n(sym)(COO) and n(asym)(COO), respec-
tively, characteristic of the bidentate mode of coordina-
tion of the carboxylato ligand [5].
ð2Þ
FD mass spectra (field desorption) and elemental
analyses of the products indicate their composition to be
?
?
[Cp2Ta(H)(acac)]BF4 and [Cp2Ta(H)(dbm)]BF4 and a
loss of dihydrogen in the reaction of 2 with the
corresponding b-diketon. Four signals observed for the
cyclopentadienyl protons in their 1H-NMR spectrum
confirm a disymmetrical distribution of the three s-
bonds.The low-field resonance of the residual hydride
This structure is confirmed by X-ray analysis. An
ORTEP view of the cation [Cp2Ta(H)(aba)]ꢁ is shown on
?
(dꢀ13.36 and 13.58 ppm for 4a and 4b) on Ta agrees
/
with strong electron-withdrawing properties of the
dicarbonyl ligand coordinated in these cationic Ta(V)
complexes. Moreover,
(5JHÃH
0.8 Hz) is observed for 4a between the TaÃ
and the methinic proton.
a weak coupling constant
ꢀ
/
/H
As proposed on Scheme 1, the formation of 4 may
involve in the first step the co-ordination of the carbonyl
group at the metal, probably in central position. The
Fig. 1. ORTEP drawing of the cation [Cp2Ta(H)(aba)]ꢁ in 3. Hydrogen
?
atoms, except the hydride (H*), are omitted for clarity. Selected bond
˚
CP2 2.070, TaÃH*
distances (A) and angles (8): TaÃ
/
CP1 2.082, TaÃ
/
/
1.65(4), TaÃ
TaÃO2 59.47(7), O1Ã
are the geometrical centers of C1Ã
/
O1 2.168(2), TaÃ
TaÃH* 70(1), O2Ã
C5 and C10Ã
/
O2 2.177(2), CP1Ã
TaÃH* 129(1); CP1 and CP2
C14 rings, respectively.
/
TaÃ
/
CP2 132.7, O1Ã
/
/
/
/
/
/
/
/
Scheme 1. Proposed mechanism of formation of 4.

O. Blacque et al. / Journal of Organometallic Chemistry 656 (2002) 139ꢂ
/
145
141
generated enol group would then take part in a
TaÃHꢀ ꢀ ꢀHÃO hydrogen bond that induce a dihydrogen
elimination.
/
/
2.3. 2-Aminobenzenethiol
Compound 5 (Eq. (3)) is obtained in good yield as a
yellow solid by reaction of an excess of 2-aminobenze-
nethiol (abtH) with the cationic dihydride tantalocene
?
Scheme 2. Proposed mechanism of formation of 6.
complex 2×
/
PF6. The formulation [Cp2Ta(H)(abt)]PF6 is
consistent with its analytical and mass spectrometric FD
data.
tantalocene sulfur complexes with a single TaÃ
/
S bond
[7].
The mechanism of formation of 5 (Scheme 2) may
involve an initial coordination of the sulfur atom (SH)
on the central lobe of a1 molecular orbital resulting in
formation of sulphonium unit bearing an acidic hydro-
gen. The next step may consist either in a direct
elimination of H2 (interaction of this acidic hydrogen
with one of the two hydrides) and co-ordination of the
amine on liberated metallic site, or in an intra-ligand
migration of this hydrogen from sulfur to nitrogen
(formation of ammonium group) followed by elimina-
ð3Þ
The two low n(NH2) frequencies at 3306 and 3260
cmꢃ1 observed in the IR spectrum of compound 5
suggest the existence of a coordinated NH2-group at
tantalum atom. However, the coordination regioselec-
tivity of the aminobenzenethiolato ligand could not be
inferred from the spectroscopic data, so an X-ray
diffraction study of 5 has been carried out. The structure
of the cation is shown on Fig. 2.
tion of H2 and formation of TaÃ/N bond. On the other
hand, an initial attack of amine function on lateral lobe
of a1-orbital seems to be not plausible, because the
formation of 5 in that case should involve an interaction
The molecular structure of 5 reveals that the bidentate
ligand forms a five-membered ring in which the NH2-
of the TaÃ
/
H hydride with a hydrogen from the less
polarised H Ã
/S bond.
group lies on the opposite side with respect to the
˚
S bond length of 2.5160(7) A
hydride ligand. The TaÃ
/
2.4. 2-Thiopyridine
falls in the typical range of values observed for
In recent years, several examples of dihydrogene
complexes [8] and those with unconventional hydrogen
bond 1d1h derived from 2-thiopyridine (pySH) as basic
ancillary ligand and late-transition metal hydrides have
been reported. It was of interest to examine the
reactivity of such ligand with early-transition metal
complexes such as tantalocene hydride.
?
Addition at 0 8C of pySH to a solution of Cp2TaH3
(1) in THF in presence of Ph3C×PF6 rapidly results in
the formation of the two major products 6 and 7 in 60/
/
40 ratio, together with traces of the isomer 6?, as
observed by H-NMR analysis. Only the isomer 6 has
1
been obtained in analytically pure form by re-crystal-
lisation of the crude material at low temperature
(ꢃ30 8C). By heating the solution of the mixture up
/
to 30 8C, kinetically controlled complex 6 undergoes
fast and quantitative rearrangement leading to the
thermodynamically controlled isomer 6? and unchanged
compound 7 (Eq. (4)). Re-crystallisation of their mixture
again only leads to the pure complex 6?.
Fig. 2. ORTEP drawing of the cation [Cp2Ta(H)(abt)]ꢁ in 5. Hydrogen
?
atoms, except hydride (H*), are omitted for clarity. Selected bond
˚
Analytical, mass spectroscopic FD and 1H-NMR
spectroscopic data are in agreement with a common
distances (A) and angles (8): TaÃ
/
CP1 2.102, TaÃ
/
CP2 2.087, TaÃ
/
H*
1.53(4), TaÃ
/
S 2.516(1), TaÃ
/
N 2.282(3), CP1Ã
TaÃH* 136(1).
/
TaÃ
/
CP2 132.0, SÃ
/
TaÃ
/N
?
formulation [Cp2Ta(H)(pyS)]PF6 for two isomeric com-
72.94(6), SÃ
/
TaÃH* 64(1), NÃ
/
/
/

142
O. Blacque et al. / Journal of Organometallic Chemistry 656 (2002) 139ꢂ145
/
plexes 6 and 6?, but the stereochemistry of the two
isomers can not be readily deduced from these data.
However, an X-ray diffraction study recovered the
structure of 6? (Fig. 3) and consequently allowed to
propose that of the isomer 6 shown in Eq. (4).
Crystallographic Data Base shows that only some 7% of
complexes adopt the conformation with dihedral angles
defined above in the range of 20ꢂ
of complexes (more than 55%) these angles span a range
of 160ꢂ2008. This crystallochemical topic will be
/
408. In a large majority
/
discussed elsewhere.
Our attempts to isolate compound 7 were unsuccess-
ful. The structure of 7 cannot be clearly deduced on the
basis of 1H-NMR data of mixtures 6ꢁ
/
7 (or 6?ꢁ7).
/
Nevertheless, some characteristic data (see experimental
part) can be pointed out: in CD3COCD3 solution,
spectrum of 7 (in presence of 6) shows a singlet at 1.93
ppm (2H) and two multiplets at 5.03 (4H) and 6.05 ppm
(4H) in the typical region for hydrides and cyclopenta-
dienyl protons, respectively, characteristic of a high
symmetry structure, e.g. C2v, around the metal. More-
over, coordination of a thiopyridine ligand on the
tantalocene moiety can be proposed according to the
presence of signals at 7.41 (1H), 8.05 (2H) and 8.44 ppm
(1H). In this way, the speculative formulations either as
ð4Þ
This study confirms the presence of an anionic (pySꢃ)
ligand that functions as a N,S-donor chelate with sulfur
atom located in central position in the structure of 6?.
The tBu substituents on C5 rings in this structure, as well
as in those of 3 and 5, span the space over the hydride
ligand, and lie on the same side (with respect to the
plane defined by the centers of the rings and tantalum
atom) of the molecule. The dihedral angles (taken as
measure of conformation) between the planes
C6,CP1,CP2/C15,CP2,CP1 are equal to 23.2, 37.7 and
29.48 for cations 3, 5 and 6?, respectively. Such
conformations are not current for this family of
(C5Ht4Bu)2M metallocenes. An inspection of Cambridge
1
?
a neutral complex [Cp2Ta(H)2(h -SÃ
/
C5H4N)] or as an
1
?
ionic one [Cp2Ta(H)2(h -SÃ
/
C5H4NH)]PF6 may be pro-
posed for complex 7.
3. Conclusions
Although we showed that the bidentate LÃ
/
XH
ꢁ
?
ligands easily coordinate to [Cp2TaH2] cation, we
were not able to detect clearly an intramolecular
protonꢂ
/
hydride interaction. The unstable intermediate
[Cp2Ta(H)2(LÃ
XH)]ꢁ liberates rapidly the dihydrogen
molecule and gives rise to formation of new (O,O?)Ã or
(N,S)Ãbidentate cationic Ta(V) complexes 3, 4, 5, 6 and
?
/
/
/
6?. Work is currently in progress to investigate a specific
synthesis of 7 in order to examine properties and
structural parameters of this complex.
4. Experimental
All reactions were performed under an argon atmo-
sphere by using Schlenk techniques. Solvents were
distillated from sodium benzopohenone ketyl. The
following instruments were used in this work: Bruker
AC 200 (RMN); Bruker IFS 66v spectrophotometer
(IR); Finnigan MAT 311 (field desorption mass spec-
tra); 1108 CHNS-O FISONS Instruments (elemental
analysis).
NMR spectra were recorded in CDCl3 (otherwise
stated), and chemical shifts are reported in ppm from
tetramethylsilane.
?
The tantalocene hydride Cp2TaH3 [9] and the ferrici-
nium [10] salts were prepared by published procedures.
Other reagents were degassed and stored under argon.
ꢁ
?
Fig. 3. ORTEP drawing of the cation [Cp2Ta(H)(pyS)] in 6?. Hydro-
gen atoms, except hydride (H*), are omitted for clarity. Selected bond
˚
distances (A) and angles (8): TaÃ
/
CP1 2.091, TaÃ
N 2.196(6), CP1Ã
TaÃH* 131(5).
/
CP2 2.121, TaÃ
/
H*
1.58(6), TaÃ
/
S 2.509(2), TaÃ
/
/
TaÃ
/
CP2 130.4, SÃ
/
TaÃ
/N
64.1(2), SÃTaÃ
/
/
H* 67(5), NÃ
/
/

O. Blacque et al. / Journal of Organometallic Chemistry 656 (2002) 139ꢂ
/
145
143
2
2
?
?
4.1. [Cp2Ta(H)(h -OOCÃ
/
C6H4-o-NH2)]PF6 (3)
4.4. [Cp2Ta(H)(h -o-SÃ
/
C6H4Ã
/
NH2)]PF6 (5)
?
A solution of Cp2TaH3 (0.12 g, 0.28 mmol) in THF
PF6
(0.11 g, 0.28 mmol) and 2-aminobenzoıc acid (39 mg,
¨
One equivalent of Ph3C×
/
PF6 (55 mg, 0.14 mmol) and
(10 ml) was treated with one equivalent of Ph3C×
/
an excess of 2-aminobenzenethiol (40 ml, 0.28 mmol)
?
were added to a solution of Cp2TaH3 (60 mg, 0.14
0.28 mmol). The volatiles were removed in vacuo and
the residue was washed with pentane (yield: 80%). An
analytically pure sample was obtained by recrystallisa-
mmol) in THF (10 ml). The solvent was eliminated
under reduced pressure after 10 min stirring, and the
yellow residue was washed with pentane (yield: 85%).
Yellow crystals were obtained by recrystallisation from
tion from THFꢂether.
/
Elemental Anal. Found: C, 42.81; H, 4.56; N, 2.60.
Calc. for C25H33TaNO2PF6: C, 42.56; H, 4.72; N,
CHCl3ꢂether.
/
Elemental Anal. Found: C, 41.57; H, 4.63; N, 2.21.
Calc. for C24H33TaNSPF6: C, 41.57; H, 4.80; N, 2.02%.
1H-NMR, d: 1.38 (s, 18H, Bu), 4.81 (m, 2H, C5H4),
5.42 (m, 2H, C5H4), 5.90 (m, 2H, C5H4), 6.17 (m, 2H,
1
t
1.99%. H-NMR, d: 1.35 (s, 18H, Bu), 5.30 (m, 2H,
C5H4), 5.78 (m, 2H, C5H4), 6.08 (m, 2H, C5H4), 6.6 (m,
2H, C5H4 and m, 2H, Ph), 7.3 (m, 1H, Ph), 7.48 (m, 1H,
Ph), 13.10 (s, 1H, TaH) (NH2: not observed). IR (KBr
pellet, cmꢃ1): 1627s, n(sym)(COO); 1500 s, n(asym)(COO);
3505s, 3397s, n(NH2). FDMS (CHCl3): m/z 560.2.
t
C5H4), 6.7ꢂ7.4 (m, 4H, Ph), 8.30 (s, 1H, TaH) (NH2: not
/
observed). IR (KBr pellet, cmꢃ1): 3306s, 3260s, n(NH2).
FDMS (CHCl3): m/z 548.2.
2
?
4.5. [Cp2Ta(H)(h -2-SC5H4N)]PF6 (6 and 6?)
?
4.2. [Cp2Ta(H)(acac)]BF4 (4a)
One equivalent of Ph3C×
/
PF6 (73 mg, 0.19 mmol) and
One equivalent of Ph3C×BF4 (0.14 g, 0.35 mmol) and
/
of 2-mercaptopyridine (21 mg, 0.19 mmol) were added
to a solution of 1 (0.8 g, 0.19 mmol). After stirring 5 min
at 0 8C, the volatiles were eliminated under reduced
pressure to give a mixture of 6 and 7 (with trace of 6?) in
75% overall yield. After washing with ether, a few white
crystals of 6 can be isolated by fractional crystallisation
two equivalents of acetylaceton (70 ml, 0.7 mmol) were
?
added to a solution of Cp2TaH3 (0.15 g, 0.35 mmol) in
THF (10 ml). After stirring 15 min, the solvent was
removed in vacuo and the crude material was washed
with toluene and pentane to give a pale yellow solid in
good yield (75%). Recrystallisation from chloroformꢂ
/
(CHCl3ꢂ
/
ether).
ether gave white microcrystals.
Elemental Anal. Found: C, 44.43; H, 5.85. Calc. for
C23H34TaO2BF4: C, 45.27; H, 5.69%. 1H-NMR, d: 1.36
Carried out at 40ꢂ45 8C, the same reaction leads to
/
the formation of a mixture containing only 6? and 7.
Complex 6? is obtained as a white microcrystalline solid
by slow recrystallisation of the crude material in a
(s, 18H, tBu), 1.98 (s, 3H, COMe), 2.09 (s, 3H, COMe),
5
5.67 (m, 2H, C5H4), 5.88 (d, JHH
ꢀ
/
0.8 Hz, 1H, COÃ
/
CHCl3ꢂ
/
ether mixture at low temperature (ꢃ30 8C).
/
CH Ã
/
CO), 5.91 (m, 2H, C5H4), 6.27 (m, 2H, C5H4), 6.39
5
(m, 2H, C5H4), 13.36 (d, JHH
ꢀ0.8 Hz, 1H, TaH). IR
/
4.5.1. Isomer 6
Elemental Anal. Found: C, 40.72; H, 4.33; N, 2.51.
Calc. for C23H31TaNSPF6: C, 40.66; H, 4.60; N, 2.06%.
(KBr pellet, cmꢃ1): 1588s, 1536s, n(CO). FDMS
(CHCl3): m/z 523.3.
t
1H-NMR, d: 1.29 (s, 18H, Bu), 5.25 (m, 2H, C5H4),
5.36 (m, 2H, C5H4), 5.82 (m, 2H, C5H4), 6.56 (m, 2H,
C5H4), 6.72 (m, 1H, C5H4N), 6.93 (m, 1H, C5H4N), 7.49
(m, 1H, C5H4N), 8.02 (m, 1H, C5H4N), 8.48 (s, 1H,
TaH). FDMS (CHCl3): m/z 534.2.
?
4.3. [Cp2Ta(H)(dbm)]BF4 (4b)
One equivalent of Ph3C×
/
BF4 (0.14 g, 0.35 mmol) and
two equivalents of dibenzoylmethane (0.16 g, 0.7 mmol)
?
were added to a solution of Cp2TaH3 (0.15 g, 0.35
mmol) in THF (10 ml). After stirring for 15 min, the
solvent was eliminated under reduced pressure and the
4.5.2. Isomer 6?
Elemental Anal. Found: C, 40.84; H, 4.56; N, 2.55.
Calc. for C23H31TaNSPF6: C, 40.66; H, 4.60; N, 2.06%.
t
yellow residue was washed with toluene (2ꢄ
pentane (5 ml) (75% yield). Recrystallisation from
chloroformꢂether gave white crystals.
/5 ml) and
1H-NMR, d: 1.35 (s, 18H, Bu), 4.69 (m, 2H, C5H4),
5.48 (m, 2H, C5H4), 6.01 (m, 4H, C5H4), 6.62 (m, 1H,
C5H4N), 7.18 (m, 1H, C5H4N), 7.56 (m, 1H, C5H4N),
8.52 (m, 1H, C5H4N), 9.06 (s, 1H, TaH). FDMS
(CHCl3): m/z 534.2.
/
Elemental Anal. Found: C, 53.69; H, 4.96. Calc. for
C33H38TaO2BF4: C, 53.97; H, 5.22%. 1H-NMR, d: 1.30
t
(s, 18H, Bu), 5.44 (m, 2H, C5H4), 5.57 (m, 2H, C5H4),
1
Characteristic H-NMR spectroscopic data for com-
t
pound 7: (CD3)2CO, d: 1.31 (s, 18H, Bu), 1.93 (s, 2H,
6.33 (m, 2H, C5H4), 6.53 (m, 2H, C5H4), 7.01 (s, 1H,
CO), 13.58 (s, 1H, TaH). IR (KBr pellet,
COÃ
/
CH Ã
/
TaH), 5.03 (m, 4H, C5H4), 6.08 (m, 4H, C5H4), 7.13 (m,
1H, C5H4N), 8.05 (m, 2H, C5H4N), 8.44 (m, 1H,
C5H4N); in CDCl3, the two Cp? protons are observed
cmꢃ1): 1592s, 1528s, n(CO). FDMS (CHCl3): m/z
647.3.

144
O. Blacque et al. / Journal of Organometallic Chemistry 656 (2002) 139ꢂ145
/
Table 1
Crystallographic data for complexes
2
2
?
?
3
[Cp2TaH(h -O2CC6H4-o-NH2ÃO,O?][PF6],
5
[Cp2TaH(h -SC6H4-o-NH2ÃS,N][PF6][THF] and 6?
2
?
[Cp2TaH(h -2-SCC6H4NÃS,N][PF6]
Compound
3
5
6?
Empirical formula
M
C25H33F6NO2PTa
705.44
C28H41F6NOPSTa
765.60
C23H31F6NPSTa
679.47
¯
Crystal system, space group
˚
Monoclinic, P21/n
12.2340(3)
Triclinic, P
/
1
/
Orthorhombic, P2cb
8.3450(2)
a (A)
˚
10.2570(2)
11.5110(3)
13.9940(3)
b (A)
˚
c (A)
16.6050(4)
12.9860(2)
16.6690(3)
17.4100(3)
a (8)
b (8)
g (8)
V (A )
Z
109.2100(14)
91.3820(14)
106.3741(12)
1744.30(6)
2
94.7430(13)
3
˚
3324.0(4)
4
1.782
2216.4(2)
4
1.864
Dcalc (Mg mꢃ3
)
1.713
3.887
Lin. Absorption coefficient (mmꢃ1
F(000)
)
4.308
1700
4.749
1310
754
0.15ꢄ0.15ꢄ0.03
Crystal size (mm3)
0.40ꢄ0.35ꢄ0.2
0.12ꢄ0.12ꢄ0.12
u range (8) for collection
hkl/ranges
2.07ꢂ
/
30.09
1.97ꢂ
/
27.48
2.34ꢂ
/
27.45
05h 517, 05k 523, l 5918 913, ꢃ14k 5ꢁ13, ꢃ185l 516 05h 510, 05k 521, 05l 522
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I ꢀ2s(I)]
R indices (all data)
7624/0/329
1.042
6779/0/356
1.060
2947/1/318
1.060
R1 aꢀ0.0268, wR2 bꢀ0.0581
R1ꢀ0.0273, wR2ꢀ0.0614
R1ꢀ0.0308, wR2ꢀ0.0632
R1ꢀ0.0252, wR2ꢀ0.0581
R1ꢀ0.0273, wR2ꢀ0.0595
0.07(1)
R1 aꢀ0.0330, wR2 bꢀ0.0608
Absolute structure, Flack
w
c/a, b
rmax, rmin (e A
0.0165, 4.1865
0.57, ꢃ1.35
0.0211, 0.7748
0.78, ꢃ1.37
0.0204, 8.5496
0.91, ꢃ1.135
ꢃ3
˚
)
a
R1ꢀS(jFojꢃjFcj)/SjFoj.
wR2ꢀ[Sw(F2oꢃF2c)2/S[w(F2o)2]1/2
b
c
.
wꢀ1/[s2(F2o)ꢁ(aP)2ꢁbP] with Pꢀ(Fo2ꢁ2F2c)/3.
at 4.75 (m, 4H) and near 5.8 ppm (very broad signal,
4H) at 293 K.
Crystallographic data and refinement parameters are
gathered in Table 1.
4.5.3. X-ray structure analyses
Crystals of 3, 5 and 6? suitable for X-ray studies were
mounted on a Nonius Kappa CCD diffractometer. The
5. Supplementary material
Crystallographic data for structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 174347 for compound 3, no.
174348 for compound 5 and no. 174349 for compound
6?. Copies of this information may be obtained free of
charge from The Director, CCDC, 12, Union Road,
unit cell determinations and data collections were
˚
Ka radiation (lꢀ0.71073 A) at
carried out with Moꢂ
/
/
low temperature (110 K). The measured intensities were
reduced with DENZO program [11]. The structures were
solved via direct methods and Patterson syntheses with
SHELXS-97. All models were further refined with full-
matrix least-squares methods (SHELXL-97) based on jF2j
[12]. All non-hydrogen atoms were refined with aniso-
tropic thermal parameters. The hydride ligands in these
three complexes were located from difference Fourier
maps and isotropically refined. Other hydrogen atoms
were included in calculated positions and refined with a
riding model. The three compounds studied are the PF6
salts of organometallic cations that lie in general
positions. The anions in 3 and 5 also occupy the general
positions, whereas in 6? they are placed on two-fold
axes. Some disorder of F atoms is observed in the
structure of 6?, but it has no influence on metric
parameters of the cation. There is one solvent molecule
(THF) per one cation and one anion in the lattice of 5.
Cambridge CB2 1EZ (Fax: ꢁ44-1223-336-033 or e-mail:
deposit@ccdc.cam.ac.uk or http//www.ccdc.cam.ac.uk).
/
Acknowledgements
Acknowledgement is made to the MS laboratory of
the University of Regensburg for recording the field
desorption mass spectra.
References
[1] (a) D. Milstein, J.C. Calabrese, I.D. Williams, J. Am. Chem. Soc.
108 (1986) 6387;

O. Blacque et al. / Journal of Organometallic Chemistry 656 (2002) 139ꢂ
/
145
145
(b) R.C. Stevens, R. Bau, D. Milstein, O. Blum, T.F. Koetzle, J.
Chem. Soc. Dalton Trans. (1990) 1429;
[3] J.P. Campbell, J.-W. Hwang, V.G. Young, R.B. Von Dreele, C.J.
Cramer, W.L. Gladfelter, J. Am. Chem. Soc. 120 (1998) 521.
[4] P. Sauvageot, A. Sadorge, B. Nuber, M.M. Kubicki, J.-C.
(c) J.C. Lee, A.L. Rheingold, B. Muller, P.S. Pregosin, R.H.
Crabtree, J. Chem. Soc. Chem. Commun. (1994) 1021;
(d) S. Park, R. Ramachandran, A.J. Lough, R.H. Morris, J.
Chem. Soc. Chem. Commun. (1994) 2201;
Leblanc, C. Moıse, Organometallics 38 (1999) 2133.
¨
[5] G.B. Deacon, R.J. Phillips, Coord. Chem. Rev. 33 (1980) 227.
[6] J.W. Lauher, R. Hoffmann, J. Am. Chem. Soc. 98 (1976)
1729This a1 frontier orbital has three main lobes localized in the
plan bisecting the metallocene fragment of C2v symmetry: one
central oriented down the 2-fold axis of the complex and two
lateral ones perpendicular to this axis..
(e) A.J. Lough, S. Park, R. Ramachandran, R.H. Morris, J. Am.
Chem. Soc. 116 (1994) 8356;
(f) E. Peris, J.C. Lee, J.R. Rambo, O. Eisenstein, R.H. Crabtree,
J. Am. Chem. Soc. 117 (1995) 3485;
[7] (a) J.-C. Daran, B. Meunier, K. Prout, Acta Crystallogr. Sect. B
35 (1979) 1709;
(g) W. Xu, A.J. Lough, R.H. Morris, Inorg. Chem. 35 (1996)
1549;
(b) J.A. Hunter, W.E. Lindsell, K.J. McCullough, R.A. Parr,
M.L. Sholes, J. Chem. Soc. Dalton Trans. (1990) 2145;
(c) J.E. Nelson, J.E. Bercaw, R.E. Marsh, M.L. Henling, Acta
Crystallogr. Sect. C 48 (1992) 1023;
(h) S. Park, A.J. Lough, R.H. Morris, Inorg. Chem. 35 (1996)
3001;
(i) W. Yao, R.H. Crabtree, Inorg. Chem. 35 (1996) 3007;
(j) R.H. Crabtree, P.E. Siegbahn, O. Eisenstein, A.L. Rheingold,
T.F. Koetzle, Acc. Chem. Rev. 29 (1996) 348;
(k) N.V. Belkova, E.S. Shubina, A.V. Ionidis, L.M. Epstein, H.
Jacobsen, A. Messmer, H. Berke, Inorg. Chem. 36 (1997) 1522;
(l) S. Aime, M. Fe´rriz, R. Gobetto, E. Valls, Organometallics 18
(1999) 2030;
(d) H. Brunner, M.M. Kubicki, J-C. Leblanc, C. Moıse, F.
¨
Volpato, J. Wachter, J. Chem. Soc. Chem. Commun. (1993) 851;
(e) G. Proulx, R.G. Bergman, Organometallics 15 (1996) 133;
(f) A. Sadorge, P. Sauvageot, O. Blacque, M.M. Kubicki, C.
Moıse, J.-C. Leblanc, J. Organomet. Chem. 575 (1999) 278.
¨
[8] (a) M. Schlaf, A.J. Lough, R.H. Morris, Organometallics 12
(1993) 3808;
(m) D-H. Lee, B.P. Patel, E. Clot, O. Eisenstein, R.H. Crabtree,
Chem. Commun. (1999) 297;
(b) M. Schlaf, A.J. Lough, R.H. Morris, Organometallics 15
(1996) 4423;
(n) M.A. Esteruelas, E. Gutie´rrez-Puebla, A.M. Lopez, E. Onate,
J.I. Tolosa, Organometallics 19 (2000) 275;
(c) Y. Guari, J.A. Ayllon, S. Sabo-Etienne, B. Chaudret, B.
Hessen, Inorg. Chem. 37 (1998) 640.
[9] J.-C. Leblanc, J.-F. Reynoud, C. Moıse, C. R. Acad. Sci. Ser II
¨
(o) K. Abdur-Rashid, D.G. Gusev, A.J. Lough, R.H. Morris,
Organometallics 19 (2000) 834.
[2] (a) T.B. Richardson, S. de Gala, R.H. Crabtree, P.E.M. Siegbahn,
J. Am. Chem. Soc. 117 (1995) 12875;
298 (1982) 755.
[10] N.G. Connelly, W.E. Geifer, Chem. Rev. 96 (1996) 877.
[11] Z. Otwinowski, W. Minor, Methods Enzymol. 276 (1997) 307.
[12] G.M. Sheldrick, SHELXS-97 and SHELXL-97, University of Gottin-
(b) L.M. Epstein, E.S. Shubina, E.V. Bakhmutova, L.N. Saitku-
lova, V.I. Bakhmutov, A.L. Chistyakov, I.V. Stankevich, Inorg.
Chem. 37 (1998) 3013.
¨
gen, Germany, 1997.