[2+2] Cyclo-addition reactions of bis-pentamethylcyclopentadienyl zirconium metal complexes containing terminal chalcogenide ligands with the phospha-alkyne PCtBu. Syntheses, crystal and molecular structures of the four complexes complexes. See

Article abstract of DOI:10.1016/S0022-328X(03)00047-0

The chalcogenide complexes [Zr(η⁵-(C₅ Me₅)₂(=E))] (E=S, Se), (generated in situ from the corresponding pyridine adducts), undergo [2+2] cyclo-addition reactions with the phospha-alkyne ^tBuCP to afford

Full text of DOI:10.1016/S0022-328X(03)00047-0

Journal of Organometallic Chemistry 672 (2003) 1Á10
/
www.elsevier.com/locate/jorganchem
[2ꢀ
/
2] Cyclo-addition reactions of bis-pentamethylcyclopentadienyl
zirconium metal complexes containing terminal chalcogenide ligands
with the phospha-alkyne PCtBu. Syntheses, crystal and molecular
structures of the four complexes [Zr(h5-(C5Me5)2(SC(tBu)Ä
/
P))],
[Zr(h5-(C5Me5)2(SeC(tBu)Ä
/
P))], [Zr(h5-(C5Me5)2(SC(tBu)Ä
PC(Ph)ÄN))]
/
PSe))]
and [Zr(h5-(C5Me5)2(SC(tBu)Ä
/
/
Sarah E. d’ArbeloffÁ
Wilson a, Peter B. Hitchcock a, John F. Nixon a,*,
/
Hiroyuki Kawaguchi b,1, Kazuyuki Tatsumi b
a School of Chemistry, Physics and Environmental Science, University of Sussex, Brighton BN1 9QJ, Sussex, UK
b Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-01, Japan
Received 1 December 2002; received in revised form 9 January 2003; accepted 9 January 2003
Abstract
The chalcogenide complexes [Zr(h5-(C5Me5)2(Ä
undergo [2ꢀ
2] cyclo-addition reactions with the phospha-alkyne BuCP to afford the structurally characterised complexes [Zr(h5-
(C5Me5)2(SC(t Bu)ÄP))] and [Zr(h5-(C5Me5)2(SeC(tBu)Ä
P))]. The former complex undergoes ring expansion reactions with either
selenium to afford [Zr(h5-(C5Me5)2(SC(tBu)ÄPSe))] or with PhCN to give [Zr(h5(C5Me5)2(SC(tBu)Ä
PC(Ph)ÄN))] which have also
been characterised structurally.
/
E))] (Eꢁ
/
S, Se), (generated in situ from the corresponding pyridine adducts),
t
/
/
/
/
/
/
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Phospha-alkyne; Cyclo-addition; Chalcogenide; Zirconium; Ring expansion
1. Introduction
Thus, treatment of [PPh4][W(h5-C5Me5)S3] with one
equivalent of PCtBu at room temperature afforded
[PPh4][W(h5(C5Me5)(S)(S2PCtBu))], which reacts with
dry O2 to give [W(h5-(C5Me5)(S)(S2PCtBu))]2 [8]
(Scheme 1)
There is considerable current interest in the study of
metal sulphides [1,2]. The reactivity of certain transition
metal sulphides towards alkenes [3] and alkynes [4,5],
has been discussed. Recent reports by Goodman and
Rauchfuss [6] describe the addition of nitriles to the
tetrasulphido anion [ReS4]ꢂ, and we have previously
Although a variety of [2 ꢀ
addition reactions of the phosphaalkyne PCtBu have
2] cyclo-additions have not
/
1], [3ꢀ
/
2] and [4ꢀ
/
2] cyclo-
also been described, [2ꢀ
/
been as widely developed [9,10]. When PCtBu is heated,
in the absence of solvent, [11] forming the remarkable
tetraphosphacubane, P4Ct4Bu4, the likely first step
discussed the ready [3ꢀ2] cyclo-addition of alkynes and
/
the phospha-alkyne, PCtBu, to the anionic mononuclear
trisulphido complex [PPh4][W(h5-(C5Me5)(S)3)], con-
involves a [2ꢀ
diphosphacyclobutadiene P2Ct2Bu2, followed by a head
to tail dimerisation and a further [2ꢀ2] cycloaddition
step. Supporting evidence [12Á14] came from a subse-
/2] self cyclo-addition to give the 1,3-
taining three terminal WÄ
/
S bonds [7,8].
/
* Corresponding author. Tel.: ꢀ
196.
E-mail address: j.nixon@sussex.ac.uk (J.F. Nixon).
/
44-273-678-536; fax: ꢀ44-273-677-
/
/
quent study of the reaction of the zirconium complex
[Zr(h5-C5H5)2P2C2t Bu2] with C2Cl6 also leading to the
tetraphosphacubane, however in this case the tricyclic
1
Present address: Coordination Chemistry laboratories, Institute
for Molecular Science, Myodaiji, Okazaki, 444-8595, Japan.
0022-328X/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00047-0

2
S.E. d’ArbeloffÁ
/
Wilson et al. / Journal of Organometallic Chemistry 672 (2003) 1Á10
/
2. Results and discussion
In order to avoid the possibility of competing [2ꢀ
/3]
cyclo-addition reactions referred to in the Introduction,
mono-terminally bonded chalcogen containing com-
plexes considered for the study were [M(h5-
(C5Me5)2(Ä
and co-workers [19] synthesised [Ti(h5-C5Me5)2(py)(Ä
O)] (pyÄ
NC5H5), from [Ti(h5-C5Me5)2] and N2O, in
/
E))] (Mꢁ
/
Ti, Zr; EꢁO, S, Se). Anderson
/
/
/
the presence of pyridine, in order to stabilise the oxo-
titanocene moiety. Likewise, Bergman and co-workers
[20] obtained the analogous terminal sulphido complex
[Ti(h5-C5Me5)2(py)(Ä
/
S)]
by
treating
[Ti(h5-
C5Me5)2(py)(S)(h2-C2H4)] with S8. Terminal zirconium
oxo complexes have been isolated only recently by
Bergman and co-workers [21,22] from a reaction in
which [Zr(h5-C5Me5)2(Ä
/
O)] (generated as a reactive
intermediate by the thermal elimination of benzene
from [Zr(h5-C5Me5)2(OH)(Ph)], or by deprotonation
of [Zr(h5-C5Me5)2(OH)(OSO2CF3)] with KN(SiMe3)2)
which was subsequently trapped by both nitriles and
alkynes. Parkin and co-workers [23] isolated the term-
Scheme 1.
tetraphosphatricyclo-octadiene was also observed,
which must have been formed by a head to head
dimerisation of the key 1,3-diphosphacyclobutadiene
intermediate.
inal zirconium(IV) oxo complex, [Zr(h5-C5Me5)2(py)(Ä
/
O)] in an analogous manner to that described for the
titanium(IV) systems and the corresponding terminal
zirconium sulphido, selenido and tellurido complexes,
A further example of a [2ꢀ
of PCtBu involves its reaction with the stable distannene
R2SnꢁSnR2, (Rꢁ(Me3Si)2CHÁ), (in equilibrium with
the corresponding stannylene) to give the structurally
/2] cycloaddition reaction
1Á3, [21,23] have been synthesised as shown in Scheme
/
3. Although addition reactions involving alkynes and
nitriles have been carried out with 1 no work has been
carried out as yet between the terminal selenido and
tellurido complexes 2 and 3.
/
/
/
characterised
(Scheme 2)
phosphadistannacyclobutene
[15].
We now describe our studies on some further [2ꢀ
/
2]
2.1. Synthesis and characterisation of [Zr(h5-
C5Me5)2(SCtBu)P] (4)
cyclo-addition reactions of the phospha-alkyne, PCtBu,
with compounds containing zirconium(IV) chalcogenide
double bonds, which are generated in situ, in view of our
ongoing interest in the similar insertion reactions with
Treatment of [Zr(h5-C5Me5)2(py)(Ä
equivalent of PCtBu, in toluene, leads to the ready
/S)] (1) with one
stable Ti(IV) and Zr(IV) imides [16Á18].
/
elimination of pyridine, affording the [2ꢀ2] cycloaddi-
/
tion product [Zr(h5-C5Me5)2(SCtBu)P] (4) (Scheme 4).
Compound 4 was fully characterised by 31P{1H}-, 1H-
,
13C{1H}-NMR spectroscopy, mass spectroscopy and
elemental analysis and its molecular structure was
established by a single crystal X-ray diffraction study.
The 31P{1H}-NMR spectrum showed a single lowfield P
resonance (d 380 ppm) which is typical of a CÄ
/P double
Scheme 2.
Scheme 3.

S.E. d’ArbeloffÁ
/
Wilson et al. / Journal of Organometallic Chemistry 672 (2003) 1Á
/10
3
Scheme 6.
three membered MÁ
plexes containing the MÁ
5 and 6 for the Zr compound).
/
PÁ
/
C ring occurs, leading to com-
Scheme 4.
/
SÁPÁC fragment (see Schemes
/
/
1
bond. The H-NMR spectrum shows both the signals
for the tBu group (relative intensity 3) and a single
resonance due to the two magnetically equivalent C5Me5
ligands (relative intensity 10). The 13C{1H}-NMR
spectrum clearly shows, as well
Complex 5 was fully characterised by NMR spectro-
scopy (dP 50.7 ppm), mass spectroscopy and by single
crystal X-ray diffraction studies, the latter confirming
that the unsaturated ring carbon atom, rather than the
phosphorus atom, is s bonded to the metal centre.
In the present work, the molecular structure of 4 in
the solid state was confirmed to be that of 4a by a single
crystal X-ray diffraction study (see Fig. 1). establishing
the presence of the ZrÁ
/
SÁ
/
CÁP four-membered ring
/
system, in which phosphorus is attached to the metal
centre and the C-tert-buyl group is located as far as
possible from the sterically demanding Cp* ligands.
Unfortunately, because of some disorder in the tBu
fragment, bond lengths and angles can only be approxi-
mately determined. Since the nucleophilic sulphur would
probably preferentially bind to the positively charged P
as the resonances for the tBu and Cp* groups, a doublet
at 191 ppm (1J(CP) 104 Hz), which can be assigned to the
unsaturated carbon within the four-membered ZrÁ
/
SÁ
/
CÁP ring. The mass spectrum shows a parent ion (m/z
/
492). The above data are consistent with the two
possible isomeric structures, 4a and 4b.
in the polar phospha-alkyne suggesting the [2ꢀ2]
/
cycloaddition step to afford 4 might be controlled by
the bulky Cp* groups. On the other hand, different
Interestingly, the 31P-NMR spectroscopic data are
very different from the unpublished data of Binger and
co-workers [24,25] for the corresponding bis-cyclopen-
tadienyl complex, 5, synthesised by a completely differ-
ent route shown in Schemes 5 and 6, which has a
structure analogous to 4b. Compound 5 (and its Ti
analogue) were synthesised
behaviour has been found [21,22,26Á
cycloaddition reactions involving the intermediates
[Zr(h5-C5Me5)2(Ä
X)] (XꢁO,S) with the alkyne MeCÅ
/
29] in a series of
/
/
/
CPh containing one bulky substituent, where in the
resulting products 7 and 8 the bulkier organic group is
located in the position a to the metal. (Scheme 7).
from the precursors [M(h5-C5H5)2(PCtBu)(PMe3)]
(MꢁTi, Zr) which on treatment with BEt3, leads to
/
the elimination of PMe3, creating a vacant site and
giving the unstable unsaturated h2-ligated phos-
phaalkyneÁ
known to usually oligomerise easily to the dimer, (Mꢁ
Zr) or the trimer, (MꢁTi), however, in the presence of
/
metallocene complex. These complexes are
/
/
Ph3PÄ
/
S at 0 8C, insertion of a sulphur atom into the
Scheme 5.
Fig. 1. Molecular structure of 4.

4
S.E. d’ArbeloffÁ
/
Wilson et al. / Journal of Organometallic Chemistry 672 (2003) 1Á10
/
Scheme 7.
Likewise in similar titanium systems the regiochemistry
of the alkyne additions is opposite to that observed for
zirconium and the bulky substituent is found in the b-
position, possibly due to the more crowded titanium
centre.
2.2. Synthesis and characterisation of [Zr(h5-
C5Me5)2(SeC(tBu)P)] (9)
Fig. 2. Molecular structure of 9.
In order to examine the generality of [2ꢀ2] cycload-
/
2.3. Synthesis and characterisation of [Zr(h5-
C5Me5)2(TeC(tBu)P)] (10)
dition reactions of metal chalcogenides with the phos-
phaalkyne, PCtBu, reactions were also carried out with
analogous terminal selenido and tellurido complexes of
zirconium. Thus, treatment of 2, with PCtBu in toluene,
under ambient conditions, led to the formation of [(h5-
C5Me5)2(SeC(tBu)P)] (9) as shown in Scheme 8. The
31P{1H}-NMR spectrum of 9 shows a singlet (d 388
ppm) exhibiting 77Se satellites, with a coupling constant
(2J(PSe) 88 Hz) whose magnitude is typical for a two-
When a similar reaction is carried out between PCtBu
and the resulting redÁ
surprisingly, on the basis of NMR studies the resulting
redÁ
brown complex [Zr(h5-C5Me5)2(TeC(tBu)P)] (10),
/brown tellurido complex 3,
/
appears to have a different structure to 4 and 9 and is
actually similar to 4b (see Scheme 9). The compound
was characterised solely by NMR and mass spectro-
scopy.
The 31P{1H} spectrum for 10 exhibits a singlet (d 95
ppm), with 127Te satellites (1J(PTe) 626 Hz), which is
considerably shifted upfield when compared with that
observed in both 4 (d 380 ppm) and 9 (d 388 ppm). The
large coupling constant is also much more typical of a
bond phosphorusÁselenium coupling suggesting a simi-
/
lar structure to 4. The 77Se{1H}-NMR spectrum dis-
plays a doublet (d 689 ppm), also with the same
coupling constant (2J(PSe) 88 Hz) and the 1H- and
13C{1H}-NMR spectra are similar in pattern to those
observed for 4. The mass spectrum shows a parent ion
(m/z 539). The molecular structure was confirmed by a
single crystal X-ray diffraction study and is shown in
Fig. 2.
one bond than a two bond phosphorusÁtellurium
/
coupling when compared to the values obtained for
2
the corresponding 1,2,4- (1J(PTe) 1021; J(PTe) 158 Hz)
The structure is in accord with the above spectro-
and 1,3,4-telluradiphosphole ring systems (2J(PTe) 148
Hz). The 127Te{1H}-NMR spectrum was also recorded
confirms this, displaying a doublet (d 664 ppm) with a
large coupling constant of 626 Hz. This information
leads to the conclusion that in 10 the isomeric complex
has been formed, where the unsaturated phosphorus is
coordinated to the tellurium and not to the Zr centre. In
scopic data and establishes the formation of the ZrÁ
CÁP ring. It is clear that the phosphorus is coordinated
to the metal centre and the CÁt
Bu is located away from
the Cp* groups, as in 4. However, again as in the case of
4, there was some disorder around the P, Se and C
t
atoms of the Bu, which precludes any detailed discus-
/
SeÁ
/
/
/
sion of bond lengths and angles.
Scheme 8.
Scheme 9.

S.E. d’ArbeloffÁ
/
Wilson et al. / Journal of Organometallic Chemistry 672 (2003) 1Á
/10
5
order to provide further confirmation, the 13C{1H}-
NMR spectrum was obtained. This shows the similar
resonances for the carbons of the tBu and Cp* groups as
those observed for complex 4, however a new doublet at
1
an unusually low field shift (d 303 ppm, J(PC) 105 Hz),
is clearly visible and can be assigned to the unsaturated
ring carbon. This downfield shift compared with the
shift for the ring carbon in 4 (d ꢂ191 ppm) may be
/
attributed to the carbon which is now bonded directly to
the metal centre. The doublet also exhibits 127Te
satellites (2J(TeC) 45 Hz) which lie in the expected range
for a two bond carbonÁtellurium coupling [20,21]
/
2
(1J(CTe) 317 Hz, J(CTe) 39 Hz). The mass spectrum of
10 shows a parent ion (m/z 587). A possible reason why
the phosphaalkyne fragment has added in the opposite
manner to that observed for the zirconium sulphide and
selenide systems may be due to the longer ZrÁ
/Te bond
distance in 10 when compared to the ZrÁS and ZrÁ
/
/
Se
Fig. 3. Molecular structure of 11 together with selected bond lengths
˚
(A) and bond angles (8): ZrÁ
1.740(3), PÁC(1) 1.709(3), SeÁP(1) 2.2284(8), C(1)Á
C(7) 2.584(2); SeÁZrÁS 86.16(2), ZrÁSÁC(1) 105.97(9), SÁ
126.3(2), C(1)ÁPÁSe 108.86(9), PÁSeÁZr 97.66(2), PÁC(1)Á
117.6(2), C(8)ÁZrÁC(16) 94.47(8).
/
S 2.5440(6), ZrÁ
/
Se 2.6385(3), SÁC(1)
/
bond lengths in 4 and 9, thus leading to the expansion of
the four membered metallacycle, allowing the approach
of the tBu groups. Unfortunately, it did not prove
possible to grow crystals of 10 suitable for X-ray
crystallography.
/
/
/
C(2) 1.534(4), ZrÁ
/
/
/
/
/
/
C(1)Á/P
/
/
/
/
/
/C(2)
/
/
resonances of the Cp* protons unexpectedly are ob-
served as a singlet, indicating that the complex is
fluxional in solution at room temperature. A single
crystal X-ray diffraction study was performed on 11 and
the molecular structure is shown in Fig. 3 together with
selected bond lengths and angles.
2.4. Further reactions of [Zr(h5-C5Me5)2(SC(tBu)P)]
(4) with chalcogenides, nitriles and isonitriles
Further ring expansion reactions of the four-mem-
bered zirconiumÁphosphaalkyne ring complex 4, with
/
other chalcogenides, nitriles and isonitriles were carried
out.
As suggested by the NMR data, the selenium atom
has clearly inserted into the ZrÁ/P bond, forming a five-
membered (ZrSPCSe) metallacycle whose PÄ
is twisted above the plane formed by the Zr, S and Se
atoms by an angle of 108. The dihedral angle between
/
C fragment
2.5. Synthesis and characterisation of [Zr(h5-
C5Me5)2(SPC(tBu)Se)] (11)
the planes formed by the two Cp* rings is 45.68. The PÁ
/
Thus, a solution of 4 and one equivalent of elemental
selenium was stirred overnight to afford [Zr(h5-
C5Me5)2(SPC(tBu)Se)] (11) as a red solid (see Scheme
10). The product was fully characterised by 31P{1H}-,
77Se{1H}-, 1H-, 13C{1H}-NMR spectroscopy, mass
spectroscopy and elemental analysis. The 31P{1H}-
˚
C(1) bond length (1.709 A) which is typical for a PÄ
double bond, is also indicated by the wide PÁC(1)ÁC(2)
bond angle (117.68). The ZrÁS distance (2.544 A) lies
within the typical ZrÁS single bond range (2.42Á
[30Á33] and has been lengthened considerably from that
observed in the starting material, 2 (2.334 A) [34], which
is consistent with the change in ZrÁS bond order from 2
to 1. The ZrÁSe bond length (2.638 A) lies in the
expected range for a ZrÁSe single bond (typically 2.658
/C
/
/
˚
/
˚
2.55 A)
/
/
/
˚
NMR spectrum of 11 shows a singlet (d ꢂ273 ppm),
/
/
shifted significantly upfield when compared with 4. The
phosphorus resonance exhibits 77Se satellites, (1J(PSe)
361 Hz), indicative of a one bond coupling. Interest-
ingly, in the 1H-NMR spectrum of complex 11, the
˚
/
/
˚
˚
Se bond length in 3 (2.480 A)).
A) [34] (ZrÄ
/
Scheme 11.
Scheme 10.

6
S.E. d’ArbeloffÁ
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Wilson et al. / Journal of Organometallic Chemistry 672 (2003) 1Á10
/
In the presence of benzonitrile the sulphido complex 2
cleanly afforded the corresponding six-membered me-
tallacycle shown in Scheme 12 which arises from a via a
[2ꢀ
/
2 ꢀ2] cycloaddition reaction.
/
It was also noted that in the case of similar reactions
with an excess of an alkyne, the insertion of a second
molecule of the alkyne, to give a six-membered ring,
does not occur. A similar reaction involving the titanium
systemswith an excess of various nitriles resulted only in
the formation of four membered (TiSCN) metallacycles.
It should be noted that Bergman and co-workers [26]
have previously reported the formation of reactive
intermediates (h5-C5Me5)2ZrÄ
/
O and (h5-C5Me5)2ZrÄ
2ꢀ2] cyclo-
addition with PhCN to generate a six-membered me-
/
S
and the sulfur compound underwent [2ꢀ
/
/
tallacycle. Likewise, a metallacycle containing the six-
Bu) Ti ring
membered TiÁ
/
PÄ
/
CRÁ
/
C(O)Á
/
CRÄ
/
P (Rꢁt
system was proposed by Cowley et al. [35], as a possible
/
Fig. 4. Molecular structure of 12 together with selected bond lengths
˚
(A) and bond angles (8): ZrÁ
1.28(1), PÁC(6) 1.85(1), PÁC(1) 1.70(1), SÁ
1.55(2), ZrÁC(25) 2.58(1); SÁZrÁN 82.3(3), SÁ
C(6)ÁN 123.1(9), PÁC(6)ÁC(7) 115.1(9).
/
N 1.988(10), ZrÁ
C(1) 1.75(1), C(1)Á
C(1)Á
/
S 2.585(3), NÁ
/
C(6)
intermediate in the reaction between [Ti(h5Á
/
/
/
/
/
C(2)
C5H5)2(CO)2] and PCtBu to form the heterocycle,
P2Ct2Bu2CO.
/
/
/
/
/P 132.9(8), PÁ
/
/
/
/
2.7. Synthesis and characterisation of [Zr(h5-
2.6. Synthesis and characterisation of
[Zr(h5C5Me5)2(SC(tBu)PC(Ph)N)] (12)
C5Me5)2{SC(tBu)PC(Ä
/
NtBu)}] (13)
Finally, the reaction between 4 and the isonitrile,
tBuNC was carried out to afford [Zr(h5-
Complex 4 was reacted with one equivalent of PhCN
in toluene at room temperature resulting in the forma-
tion of the six-membered ring complex [Zr(h5-
C5Me5)2(SC(tBu)PC(Ph)N)] (12) (Scheme 11).
The 31P{1H}-NMR spectrum of 12 shows a singlet at
137 ppm and its mass spectrum exhibits a parent ion (m/
z 595). Its molecular structure, which was confirmed by
a single crystal X-ray diffraction study, is shown in Fig.
4, together with selected bond lengths and angles.
The structure clearly shows that the nitrogen is
attached to the metal centre and the aryl group occupies
the b-position to zirconium, lying away from the bulky
C5Me5)2{SC(tBu)PC(Ä
membered ZrSCPC ring system (Scheme 13).
/
NtBu)}] (13), containing a five-
Unfortunately, although it proved difficult to grow
suitable crystals suitable for crystallography, the pro-
duct was characterised by NMR and mass spectroscopy.
The 31P{1H}-NMR spectrum shows a singlet (d 162
1
ppm) and in the H-NMR spectrum, the resonances for
the two tBu groups (d 1.4, 1.7 ppm) as well as those for
the Cp* ligands can be seen, in the ratio of 3:3:10. The
13C{1H}-NMR spectrum is the most indicative in help-
ing to determine the structure. It exhibits the required
Cp* substituents, inferring that steric factors must be
˚
the dominant influence. The NÁC bond length (1.28 A)
/
is within the expected value for a NÁ
the six-membered ring formed by ZrÁ
almost planar (S(internal angles)ꢁ7188). It is interesting to
/
C double bond and
/
SÁCÁPÁCÁN is
/
/
/
/
/
note that Bergman and co-workers [20,29] have reported
syntheses of the reactive intermediates [Zr(h5-
C5Me5)2(Ä
/
X)] (XꢁO,S) 1 and 2.
/
Scheme 13.
Scheme 12.

S.E. d’ArbeloffÁ
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Wilson et al. / Journal of Organometallic Chemistry 672 (2003) 1Á
/10
7
resonances for the tBu group attached to the PÄ
/C
used as a drying agent for acetonitrile. NMR solvents
were dried over potassium (benzene-d6), sodium (tolu-
ene-d8) or calcium hydride (dichloromethane-d2), then
vacuum transferred into ampoules and stored under
dinitrogen prior to use.
NMR spectra were recorded on a Bruker DPX 300 or
a Bruker AMX 500 spectrometer at the operating
frequencies shown below in Table 1. Chemical shifts
reported in ppm (d) are relative to the residual proton
chemical shift of the deuterated solvent (1H), the carbon
chemical shift of the deuterated solvent (13C) and
external H3PO4 (31P), Mass spectra were recorded on a
VG autospec Fisons instrument (Electron ionisation at
70 eV) by Dr. A. Abdul-Sada. Elemental analyses were
performed by Micro Analytisches Labor Pascher (Ger-
many) or A.T. Stones of the Department of Chemistry,
University College London.
fragment, as well as additional doublets for the second
tBu group, of the isonitrile moiety. The doublets for the
two ring carbons are also clearly visible. The signal for
the unsaturated ring C (d 248 ppm), lying between the P
and S, has been shifted downfield when compared to the
equivalent carbon in 4 (d 191 ppm, 1J(CP) 68 Hz) and the
t
new C (of the BuNC fragment) appears at 270 ppm
(1J(CP) 80 Hz) which is in a similar region to that
observed for the unsaturated carbon in 10 (d 303 ppm),
3. Experimental
All manipulations were carried out using conventional
high vacuum and Schlenk line techniques, under an
atmosphere of dry argon, or under a dinitrogen atmo-
sphere in an MBraun or Miller-Howe glove box.
Solvents were refluxed over suitable drying agents, and
distilled and degassed prior to use. Toluene and benzene
were refluxed over sodium, thf was refluxed over
3.1. [Zr(h5-C5Me5)2(SC(tBu)P)] (4)
PCtBu (0.021 g, 0.210 mmol) was added to a stirred
potassium. Petroleum ether (40Á
/
60 8C b.p.) and pentane
suspension of [Zr(h5-C5Me5)2(Ä
0.212 mmol) in toluene (10 ml). The reaction mixture
/S)(py)] (1) (0.100 g,
were refluxed over sodiumÁpotassium alloy. CaH2 was
/
Table 1
Crystallographic data for [Zr(h5-C5Me5)2(SC(t Bu)P)] (4), [Zr(h5-C5Me5)2(SeC(t Bu)P)] (9), [Zr(h5-C5Me5)2(SC(t Bu)PSe)] (11) and [Zr(h5-
C5Me5)2{SC(t Bu)PC(Ph)N}] (12)
4
9
11
12
Formula
C
493.84
25H39PSZr
C25H39PSeZr
540.74
Triclinic
¯
P1 (no. 2)
Brown
C25H39PSSeZr
572.80
C32H44PSNZr
596.96
Mol. wt. (g molꢂ1
Crystal system
Space group
)
Monoclinic
P21/c (no. 14)
Brown
Monoclinic
P21/n (no. 14)
Brown
Orthorhombic
P212121 (no. 19)
Red
Color of crystal
Crystal size (mm3)
Unit cell dimensions
0.20ꢃ
/0.15ꢃ
/0.04
0.14ꢃ
/
0.10ꢃ
/0.02
0.30ꢃ/0.40ꢃ/0.02
0.25ꢃ
/
0.14ꢃ0.02
/
˚
a (A)
14.5948(8)
11.9668(3)
15.0620(2)
9.810(1)
9.8946(7
13.708(1)
76.938(1)
84.8979(9)
74.7278(9)
1249.8(2)
2
10.2410(7)
18.6038(5)
14.4626(3)
9.6038(4)
9.8590(2)
31.740(2)
˚
b (A)
˚
c (A)
a (8)
b (8)
109.0125(7)
105.8013(6)
g (8)
3
V (A )
˚
2487.1(1)
4
2651.3(2)
4
3005.3(2)
4
Z
rcalc (g cmꢂ3
)
1.319
5.99
1.437
19.69
1.435
19.36
1.319
5.09
m(MoÁ
/
Ka) (cmꢂ1
Absorption range
)
0.84Á/0.99
0.68Á/0.96
0.63Á/0.96
0.36Á0.99
/
2umax (8)
55
5538
55
5242
55
6027
55
3876
No. of measured reflections
No. observed reflections
No. parameters
5534 a
5238 a
6024 a
3225 b
298
248
262
326
c
R
Rw
0.054
0.054
1.61
0.061
0.065
2.17
0.043
0.053
1.97
0.092
0.093
2.03
d
GOF e
a
All reflections used.
b
Observation criterion I ꢀ1s(I).
/
c
d
e
Rꢁ
Rwꢁ
GOFꢁ
/
SjjFojꢂ
/
jFcjj/SjFoj.
/
[{S w(jFojꢂ
/
jFcj)2}/Sw Fo2]1/2
.
/
[{S w(jFojꢂ
/
jFcj)2}/(Noꢂ
/
Np)]1/2, where No and Np denote the number of data and parameters.

8
S.E. d’ArbeloffÁ
/
Wilson et al. / Journal of Organometallic Chemistry 672 (2003) 1Á10
/
was stirred for 24 h, during which time the solution
colour changed from yellow to red. Volatiles were
removed in vacuo and the resulting red residue extracted
with hexane (15 ml). Slow evaporation of the hexane
solution led to the formation of red crystals of 4 (yield
0.064 g, 61%). Crystals suitable for X-ray analysis were
grown from a slowly cooled and concentrated hexane
31P{1H}: d 93.3 [s, 1J(PTe) 625 Hz] ppm; 125Te{1H}: d
1
1
661.4 [d, J(TeP) 625 Hz] ppm; H: d 1.76 [s, 30H, 2{h5-
C5(CH3)5}], 1.57 [s, 9H, C(CH3)3] ppm. 13C{1H}-NMR
data (benzene-d6, 295 K): d 304.0 [d, 1C, PCC(CH3)3,
1
1J(PC) 105 Hz, J(CTe) 45 Hz], 118.3 [s, 10C, 2{h5-
C5(CH3)5}], 51.4 [d, 1C, PCC(CH3)3, 2J(PC) 25 Hz], 37.9
3
[d, 3C, PCC(CH3)3, J(PC) 15 Hz], 14.4 [s, 10C, 2{h5-
solution (ꢂ
/
45 8C).
C5(CH3)5}] ppm. EIMS m/z (%): 587 (24) [Mꢀ], 487
NMR data (all in benzene-d6, 295 K).
31P{1H}: d 380.2 ppm, 1H; d 1.68 [s, 30H, 2{h5-
[Mꢂ
(PCtBu)]ꢀ.
/
C5(CH3)5}], 1.65 [s, 9H, C(CH3)3] ppm. 13C{1H} d 191.4
3.4. [Zr(h5-C5Me5)2(SC(tBu)PSe)] (11)
1
[d, 1C, PCC(CH3)3, J(PC) 104 Hz], 119.3 [s, 10C, 2{h5-
C5(CH3)5}], 45.8 [d, 1C, PCC(CH3)3, J(PC) 7 Hz], 34.5
2
[Zr(h5-C5Me5)2(SC(tBu)P)] (4) prepared as stated
above (0.100 g, 0.203 mmol) was then dissolved in
toluene (10 ml) and elemental Se (0.024 g, 0.304 mmol)
was added. The solution turned dark red rapidly and the
reaction mixture was stirred for 24 h. The solution was
filtered to remove any excess Se and the volatiles were
removed in vacuo. Recrystallisation of the resulting red
residue with hexanes (5 ml) yielded dark red crystals of
11 (yield 0.092 g, 79%). Crystals suitable for X-ray
analysis were grown from a slowly cooled hexane
3
[d, 3C, PCC(CH3)3, J(PC) 10 Hz], 11.7 [s, 10C, 2{h5-
C5(CH3)5}] ppm. EIMS m/z (%): 492 (24) [Mꢀ], 392
[Mꢂ
(PCtBu)]ꢀ. Anal. Found C, 59.61; H, 7.99; S, 6.21.
Calc. for ZrC25H39SP: C, 59.83; H, 8.16; S, 6.65%.
/
3.2. [Zr(h5-C5Me5)2(SeC(tBu)P)] (9)
PCtBu (0.028 g, 0.280 mmol) was added to a stirred
suspension of [Zr(h5-C5Me5)2(Ä
/Se)(py)] (2) (0.150 g,
solution (ꢂ
/
45 8C).
0.289 mmol) in toluene (12 ml). The reaction mixture
was stirred for 24 h, during which time the solution
colour changed from green/brown to red. The volatiles
were removed in vacuo and the resulting red residue was
extracted with hexane (15 ml). Slow evaporation of the
hexane solution led to the formation of red crystals of 9
(yield 0.073 g, 47%). Crystals suitable for X-ray analysis
were grown by slowly cooling a concentrated hexane
NMR data (all in benzene-d6, 295 K).
1
31P{1H}: d ꢂ273.4 [s, J(PSe) 360 Hz] ppm; 77Se{1H}:
/
d 568.7 [d, 1J(SeP) 360 Hz] ppm; 1H: d 1.71 [s, 30H, 2{h5-
C5(CH3)5}], 1.42 [s, 9H, C(CH3)3] ppm. 13C{1H}: d
1
239.4 [d, 1C, PCC(CH3)3, J(PC) 101 Hz], 118.4 [s, 10C,
2{h5-C5(CH3)5}], 49.2 [d, 1C, PCC(CH3)3, 2J(PC) 18 Hz],
3
37.8 [d, 3C, PCC(CH3)3, J(PC) 12 Hz], 12.6 [s, 10C,
2{h5-C5(CH3)5}] ppm. EIMS m/z (%): 571 (41) [Mꢀ],
392 [M-(SePCtBu)]ꢀ. Anal. Found C, 51.17; H, 7.12; S,
5.64. Calc. for ZrC25H39SPSe: C, 51.40; H, 7.01; S,
5.72%.
solution (ꢂ45 8C).
/
NMR data (all in benzene-d6, 295 K).
2
31P{1H}: d 388.1 [s, J(PSe) 89 Hz] ppm; 77Se{1H} d
2
608.0 [d, J(SeP) 89 Hz] ppm; 1H: d 1.74 [s, 30H,
2{C5(CH3)5}], 1.79 [s, 9H, 1H d 1.74 [s, 30H, 2{h5-
3.5. [Zr(h5-C5Me5)2{SC(tBu)PC(Ph)N}] (12)
C5(CH3)5}], 1.79 [s, 9H, C(CH3)3] ppm. 13C{1H}: d
1
184.3 [d, 1C, PCC(CH3)3, J(PC) 110 Hz], 120.2 [s, 10C,
[Zr(h5-C5Me5)2(SC(tBu)P)] (4) (0.200 g, 0.405 mmol)
was then dissolved in toluene (10 ml) and PhCN (0.083
g, 0.811 mmol) was added dropwise. The reaction
mixture was stirred for 48 h, during which time the
solution turned from light to dark red. The volatiles
were removed in vacuo and the residue was extracted
with hexane (15 ml), giving red crystals of 12 (yield 0.102
g, 42%). Crystals suitable for X-ray analysis were grown
2
2{h5-C5(CH3)5}], 43.2 [d, 1C, PCC(CH3)3, J(PC) 8 Hz],
30.5 [d, 3C, PCC(CH3)3, J(PC) 12 Hz], 10.5 [s, 10C,
3
2{h5-C5(CH3)5}] ppm. EIMS m/z (%): 539 (32) [Mꢀ],
439 [Mꢂ
(PCtBu)]ꢀ. Anal. Found C, 54.23; H, 7.40.
Calc. for ZrC25H39SeP: C, 54.52; H, 7.43%.
/
3.3. [Zr(h5-C5Me5)2(TeC(tBu)P)] (10)
from a cooled toluene solution (ꢂ308C).
/
PCtBu (0.022 g, 0.220 mmol) was added to a stirred
NMR data (all in benzene-d6, 295 K).
31P{1H}: d 136.8 ppm; H: d 8.39 [m, 2H, C(C6H5)],
1
suspension of [Zr(h5-C5Me5)2(Ä
/Te)(py)] (3) (0.125 g,
0.220 mmol) in toluene (15 ml). The reaction mixture
was stirred for a further 24 h, during which time the
solution colour changed from red to green. Volatiles
were removed in vacuo and the resulting green residue
was extracted with hexane (20 ml). This solution was
concentrated again and dried under vacuo, yielding 10
as a green solid (yield 0.084 g, 65%).
7.03 [m, 2H, C(C6H5)], 7.20 [m, 1H, C(C6H5)], 1.94 [s,
9H, C(CH3)3], 1.79 [s, 30H, 2{h5-C5(CH3)5}] ppm.
1
13C{1H}: d 220.4 [d, 1C, PCC(CH3)3, J(PC) 103 Hz],
1
189.6 [d, 1C, NC(C6H5), J(PC) 98 Hz] 133.5 [s, 1C,
NC(C6H5)], 127.2 [s, 2C, NC(C6H5)], 126.6 [d, 1C,
2
3
NC(C6H5), J(PC) 7 Hz] 125.8 [d, 2C, NC(C6H5), J(PC)
4 Hz], 118.9 [s, 10C, 2{h5-C5(CH3)5}], 47.2 [d, 1C,
PCC(CH3)3, J(PC) 19 Hz], 34.8 [d, 3C, PCC(CH3)3,
2
NMR data (all in benzene-d6, 295 K).

S.E. d’ArbeloffÁ
/
Wilson et al. / Journal of Organometallic Chemistry 672 (2003) 1Á
/10
9
3J(PC) 11 Hz], 11.5 [s, 10C, 2{h5-C5(CH3)5}] ppm. EIMS
m/z (%): 595 (22) [Mꢀ], 492 [Mꢂ(PhCN)]ꢀ, 392 [Mꢂ
(PhCN)ꢂ
(PCtBu)]ꢀ. Anal. Found C, 63.83; H, 7.34; N,
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
/
/
/
2.52; S, 5.11. Calc. for ZrC32H44SPN: C, 63.65; H, 7.58;
N, 2.39; S, 6.65%.
Acknowledgements
3.6. [Zr(h5-C5Me5)2{SC(tBu)PC(NtBu)}] (13)
We thank the Royal Society for a travel grant to help
finance this collaboration.
[Zr(h5-C5Me5)2(SC(tBu)P)] (4) (0.275 g, 0.557 mmol)
was then dissolved in toluene (12 ml) and tBuNC (0.051
g, 0.613 mmol) was added dropwise. The reaction
mixture was allowed to stir for 24 h, during which
time the solution turned from light to dark red. The
volatiles were removed in vacuo and the residue was
extracted with hexane (15 ml), giving 13 as a red solid
(yield 0.253g, 79%).
References
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Enzymes, Cofactors and Model Systems, American Chemical
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NMR data (all in benzene-d6, 295 K).
1
31P{1H}: d 162.6 ppm; H: d 1.79 [s, 9H, PC(CH3)3],
1.71 [s, 30H, 2{h5-C5(CH3)5}], 1.42 [s, 9H, NC(CH3)3]
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1
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1
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3
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/
m/z (%): 575 (68) [Mꢀ], 492 [Mꢂ t
/
( BuNC)]ꢀ, 392 [Mꢂ
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/
(PCtBu)]ꢀ.
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3.7. X-ray structure determination of 4, 9, 11 and 12
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/
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/
/
˚
0.71069 A). Absorption corrections were applied, and
the structures were solved using direct methods and
refined by full-matrix least-squares on F using the
TEXSAN package. Anisotropic refinement was applied
to all non-hydrogen atoms, and all hydrogen atoms were
put at calculated positions. For 4, sulfur, phosphorus
and carbons of the tert-butyl group are disordered with
occupancy factors of 55:45. In the case of 5, selenium,
phosphorus, and carbons of the tert-butyl group are
disordered with occupancy factors of 57:43, and they are
isotropically refined. These crystallographic data are
summarised in Table 1.
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Crystallographic data for the structural analysis have
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/
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Union Road, Cambridge CB2 1EZ, UK (Fax: ꢀ
/
44-
R. Goddard, C. Kruger, Chem. Ber. 123 (1990) 1617.
¨

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