The reactivity of an iridaphosphirene complex, [Ir{=C(But)-P(Cy)}(CO)(PPh3)2], Cy = cyclohexyl, toward electrophiles

Article abstract of DOI:10.1039/b304076n

The reactivity of an iridaphosphirene complex, [Ir{=C(Bu^t)P(Cy)}(CO)(PPh₃)₂], Cy = cyclohexyl, toward a variety of electrophiles has been examined and in all cases reactivity occurs at the phosphorus centre within the three membered ring. Reaction with several protic reagents has led to the formation of the iridaphosphirenium salts, [Ir{=C(Bu^t)P(H)(Cy)}(CO)(PPh₃)₂]X, X = BF₄^-, CF₃SO₃ or CF₃CO₂^-, two of which have been crystallographically characterised. Though thermally stable in the solid state, in dichloromethane solutions these rearrange via 1,2-hydrogen migrations over seven days to give the Ir(I)-η¹-phosphaalkene complexes, [Ir(CO)(PPh₃)₂{η¹-P(Cy)=C(H)(Bu^t )}]X, one of which (X = BF₄^-) has been crystallographically characterised. The reactions of [Ir{=C(Bu^t)P(Cy)}(CO)(PPh₃)₂] with MeI, S and Se have also been investigated and found to give the complexes, [Ir{=C(Bu^t)P(Me)(Cy)}(CO)(PPh₃)₂]I and [Ir{=C(Bu^t)P(=E)(Cy)}(CO)(PPh₃)₂] E = S or Se, the former two of which have been structurally authenticated.

Full text of DOI:10.1039/b304076n

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The reactivity of an iridaphosphirene complex,
[Ir{᎐C(But)P(Cy)}(CO)(PPh ) ], Cy ؍ cyclohexyl,
᎐
3 2
toward electrophiles
Markus Brym, Cameron Jones* and Mark Waugh
Department of Chemistry, Cardiff University, P.O. Box 912, Park Place, Cardiff,
UK CF10 3TB
Received 11th April 2003, Accepted 2nd June 2003
First published as an Advance Article on the web 18th June 2003
The reactivity of an iridaphosphirene complex, [Ir{᎐C(But)P(Cy)}(CO)(PPh ) ], Cy = cyclohexyl, toward a variety of
᎐
3
2
electrophiles has been examined and in all cases reactivity occurs at the phosphorus centre within the three membered
ring. Reaction with several protic reagents has led to the formation of the iridaphosphirenium salts, [Ir{᎐C(But)-
᎐
P(H)(Cy)}(CO)(PPh3)2]X, X = BF4Ϫ, CF3SO3Ϫ or CF3CO2Ϫ, two of which have been crystallographically
characterised. Though thermally stable in the solid state, in dichloromethane solutions these rearrange via
1,2-hydrogen migrations over seven days to give the Ir()–η1-phosphaalkene complexes, [Ir(CO)(PPh ) {η1-P(Cy)᎐
᎐
3
2
C(H)(But)}]X, one of which (X = BF4Ϫ) has been crystallographically characterised. The reactions of
[Ir{᎐C(But)P(Cy)}(CO)(PPh ) ] with MeI, S and Se have also been investigated and found to give the complexes,
᎐
᎐
3
2
[Ir{᎐C(But)P(Me)(Cy)}(CO)(PPh ) ]I and [Ir{᎐C(But)P(᎐E)(Cy)}(CO)(PPh ) ] E = S or Se, the former two of
᎐
᎐
3
2
3 2
which have been structurally authenticated.
phosphavinyl ligand and a very low field resonance for the
iridium bound carbon centre, Cα, at 331.5 ppm in its 13C NMR
spectrum. In addition, when 3 is treated with CO an η1-phos-
phavinyl complex does not result but instead PPh3 displacement
Introduction
The last five years has seen a steady increase in the interest
surrounding transition metal η2–3eϪ vinyl complexes.1 This has
largely arisen from the fact that they undergo a variety of useful
reactions with nucleophiles and electrophiles, isomerisations to
η3-allyl and carbene complexes, in addition to electron transfer
reactions. With regards to the structure and bonding exhibited
by the vast majority of these complexes, Casey et al. have made
the convincing argument that they should be considered as
metallacyclopropene complexes, 1, rather than η2-vinyl com-
plexes, 2.2 This is based on structural evidence, viz. shortness of
the M–Cα bond and the fact that the M–Cα–R fragment is often
almost perpendicular to the R–Cβ–R fragment; spectroscopic
evidence, viz. the Cα centre resonates at very low field and the Cβ
centre at much higher field in the 13C NMR spectra of these
complexes; and theoretical evidence, viz. the results of DFT
studies. It must be said, however, that a small number of
complexes have been reported which contain close to planar
vinyl ligands that are weakly η2-coordinated to the metal
centre.3
occurs to give [Ir{᎐C(But)P(Cy)}(CO) (PPh )]. Interestingly,
᎐
2
3
this complex is not stable in solution and decomposes to give
a number of products which include the novel oxo-η3-phos-
phaallyl complex, 4, which is formed via a C–C coupling of one
carbonyl ligand with the phosphavinyl fragment. Considering
the novelty of this reaction and the analogy between 3 and
metallocyclopropenes it seemed worthy to explore the further
reactivity of 3. The results of its reactions with a variety of
electrophiles are reported herein.
In our laboratory we have recently been examining the
analogy between the phosphavinyl, –C(R)᎐P(R), and vinyl
᎐
fragments and have found that the former can behave very
differently to their vinyl counterparts within the coordination
sphere of main group elements. These differences largely
revolve around the facility by which coordinated phospha-
vinyl ligands can intramolecularly couple to give a variety of
organometallic cage and heterocyclic compounds.4–8 An exam-
ination of the chemistry of transition metal–phosphavinyl
complexes has not proven as fruitful due to the fact that the
various accessible oxidation states of many transition metals
often lead to oxidative coupling of the phosphavinyl fragment
to give phosphorus containing heterocycles.9
Results and discussion
Treatment of metallocyclopropenes, 1, with protic reagents can
lead to protonation of the metal, Cα or Cβ sites depending on
the metal and/or vinyl substituents employed.1 If an analogy is
drawn with 3, its reaction with protic reagents, HX, could
potentially lead to protonation at (i) the metal centre to give a
One success we have had is with the reaction of the
phosphavinyl Grignard reagent, [CyP᎐C(But)MgCl(OEt )] Cy =
η1-phosphavinyl complex, [IrIII{η1-C(But)᎐P(Cy)}(CO)HX-
᎐
᎐
2
cyclohexyl, with Vaska’s compound, [IrCl(CO)(PPh3)2], which
(PPh3)2], (ii) the Cα centre to give a phosphaalkene complex,
affords the iridaphosphirene complex, [Ir{᎐C(But)P(Cy)}(CO)-
[IrI(CO)(PPh ) {η1-P(Cy)᎐C(H)(But)}]X or (iii) the phos-
᎐
᎐
3
2
(PPh3)2] 3, in good yield.10 Structural and spectroscopic studies
of this compound have shown that it has more in common with
the metallocyclopropene formulation of its hydrocarbon
analogues than the η2-vinyl bonding description. Data to
support this include a CPCC torsion angle of 77.9Њ within the
phavinyl P-centre to give a λ5-iridaphosphirenium complex,
[[Ir{᎐C(But)P(H)(Cy)}(CO)(PPh ) ]X, X = anion. To investi-
᎐
3
2
gate these possibilities the reaction of 3 with several acids
has been investigated and in all cases moderate yields of the
iridaphosphirenium salts, 5, resulted (Scheme 1).
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
D a l t o n T r a n s . , 2 0 0 3 , 2 8 8 9 – 2 8 9 3
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Scheme 1 Reagents and conditions: (i), HX, Et2O; (ii), 7 days, CH2Cl2;
(iii), MeI, THF; (iv), E, toluene.
Fig. 1 Structure of the cationic component of compound 5a. Selected
bond lengths (Å) and angles (Њ): Ir(1)–C(1) 1.934(8), Ir(1)–P(1)
2.3186(19), Ir(1)–P(2) 2.384(2), Ir(1)–P(3) 2.347(2), Ir(1)–C(12)
1.873(9), P(1)–C(1) 1.735(8), P(1)–H(1) 1.31(7), P(1)–C(6) 1.828(8),
C(12)–O(1) 1.169(10), C(1)–C(2) 1.512(11), C(12)–Ir(1)–C(1) 100.0(3),
C(12)–Ir(1)–P(1) 147.1(2), C(1)–Ir(1)–P(1) 47.1(2), C(12)–Ir(1)–P(3)
98.8(3), C(1)–Ir(1)–P(3) 119.8(2), P(1)–Ir(1)–P(3) 100.27(7), C(12)–
Ir(1)–P(2) 88.4(3), C(1)–Ir(1)–P(2) 138.3(2), P(1)–Ir(1)–P(2) 114.81(7),
P(3)–Ir(1)–P(2) 98.67(7), C(1)–P(1)–C(6) 119.5(4), C(1)–P(1)–Ir(1)
54.7(3), C(2)–C(1)–P(1) 138.1(6), P(1)–C(1)–Ir(1) 78.2(3).
These proved to be thermally stable in the solid state and all
exist as ion separated salts. As a result, the spectroscopic data
for the three complexes are similar. Most informative of these
come from their 31P{1H} NMR spectra which display high field
virtual triplet resonances (ca. Ϫ140 ppm) which lie ca. 20 ppm
to lower field of the iridaphosphirene resonance in 3, as would
be expected upon protonation of the heterocyclic phosphorus
centre. In addition, the IR spectra of 5 revealed shifts to higher
frequency (ca. 50 cmϪ1) for the CO stretching absorptions in
these complexes compared to that in 3 (1954 cmϪ1). This, again,
is not surprising considering that in the former complexes the
CO ligands are associated with cationic moieties.
X-ray crystal structure analyses of 5a and 5b were carried out
and in both the geometry of the phosphirenium moiety is very
similar and thus only the structure of the cation of 5a is
depicted in Fig. 1. It is noteworthy, however, that 5b crystallised
with one molecule each of toluene and CF3CO2H per
asymmetric unit. In addition, the structures of both cations are
strikingly similar to that of their neutral precursor, 3. The irid-
ium centre of 5a can be considered as having a heavily distorted
trigonal bipyramidal geometry with the carbonyl ligand and
P(1) taking up the axial sites and C(1), P(2) and P(3) in the
equatorial positions. The P(1)–C(1) interaction [1.734(8) Å] is
short for a single P–C bond but not significantly shorter than
the corresponding bond in 3, [1.753(13) Å]. In addition, the
Ir(1)–C(1) distance [1.934(8) Å] is longer than in 3 [1.918(14) Å]
but still in the normal region for localised Ir–C double bonds,11
whilst the P(1)–Ir(1) bond length [2.3186(19) Å] is significantly
shorter than the analogous distance in 3 [2.442(3) Å]. This
difference can be explained by the electron poor nature of the
phosphirenium phosphorus centre in cationic 5a relative to
the phosphirene phosphorus centre in neutral 3. The fact that
the C(6)P(1)C(1)C(2) torsion angle is 63.6Њ confirms that 5a
should be considered as an iridaphosphirenium complex rather
than a protonated η2-phosphavinyl complex. Very similar
geometrical trends have been observed in metallacyclopropene
complexes, 1, which theoretical studies suggest arise from
a degree of isolobality between the C2 fragment of the
3-membered ring and 4eϪ donor alkyne ligands.2
been observed.2 In addition, and in a related fashion to the
formation of the phosphaalkene complexes, 6, protonation of
metallocyclopropenes can occur at the Cα centre which leads to
the formation of free alkenes.12 In order to generate the
free phosphaalkene, CyP᎐C(H)(But), from 6, X = BF Ϫ, CO
᎐
4
gas was passed through a dichloromethane solution of the
phosphaalkene complex over five minutes. An examination of
the 31P{1H} NMR spectrum of the product mixture revealed
that the known phosphaalkene13 had been quantitatively dis-
placed from the cation of 6, as evidenced by the appearance of
a singlet resonance at 255 ppm. The by-product in this reaction
was found to be the previously reported compound, [Ir(CO)3-
(PPh3)2][BF4].14
The spectroscopic data for 6, X = BF4Ϫ, are consistent with its
proposed structure. Of note is its 31P{1H} NMR spectrum
which displays an AB2 pattern, the doublet signal of which
(δ 15.4 ppm) corresponds to the chemically equivalent PPh3
ligands whilst the triplet signal occurs at low field (δ 222.4 ppm)
in the normal region for η1-coordinated phosphaalkenes. The
coupling between the two signals (51 Hz) suggests a cis-
relationship between the phosphaalkene and the two phosphine
ligands.
The structure of the cationic component of 6, X = BF4Ϫ, is
depicted in Fig. 2. The molecule sits on a crystallographic
mirror plane which contains the phosphaalkene ligand and thus
its cyclohexyl substituent is necessarily disordered. There are
no close contacts between the cation and the BF4 anion, and
the 16eϪ iridium centre has a slightly distorted square planar
geometry. Both the P(1) and C(1) centres have trigonal planar
geometries and the distance between these centres [1.607(14) Å]
is normal for a localised P–C double bond.11
The reactivity of 3 toward a number of other electrophiles
was examined with similar results to its protonation. Its
treatment with MeI did not lead to oxidative addition to the
iridium centre but methylation of the phosphorus centre in the
3-membered ring to give 7 in high yield (Scheme 1). Similarly,
Although 5a–c are thermally very stable in the solid state, in
dichloromethane solutions they are less so and quantitatively
and irreversibly rearrange via 1,2-hydrogen migrations to give
the cationic Ir()–phosphaalkene complexes, 6 (Scheme 1), over
one week. It is noteworthy that similar but reversible 1,2-
hydrogen shifts between the two carbon centres in metallo-
cyclopropenes, e.g. [Cp*Re(CO) {᎐C(H)(Ph)C(o-tolyl)}], have
᎐
2
D a l t o n T r a n s . , 2 0 0 3 , 2 8 8 9 – 2 8 9 3
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Fig. 2 Structure of cationic component of compound 6. Selected
bond lengths (Å) and angles (Њ): Ir(1)–P(1) 2.328(3), Ir(1)–C(11)
1.859(9), Ir(1)–P(2) 2.3365(15), P(1)–C(1) 1.607(14), P(1)–C(5)
1.998(18), C(1)–C(2) 1.408(19), C(11)–Ir(1)–P(1) 179.7(3), C(11)–Ir(1)–
P(2) 87.81(4), P(1)–Ir(1)–P(2) 92.20(4), P(2)–Ir(1)–P(2Ј) 173.22(7),
C(1)–P(1)–Ir(1) 139.0(6), C(5)–P(1)–Ir(1) 116.2(4), P(1)–C(1)–C(2)
131.4(13).
Fig. 4 Molecular structure of compound 8. Selected bond lengths (Å)
and angles (Њ): Ir(1)–C(1) 1.945(6), Ir(1)–P(1) 2.3552(17), Ir(1)–P(2)
2.3486(16), Ir(1)–P(3) 2.3692(17), Ir(1)–C(12) 1.899(7), P(1)–C(1)
1.746(6), P(1)–S(1) 1.992(2), P(1)–C(6) 1.843(7), C(12)–O(1) 1.145(8),
C(1)–C(2) 1.503(8), C(12)–Ir(1)–C(1) 98.4(3), C(12)–Ir(1)–P(1)
143.75(19), C(1)–Ir(1)–P(1) 46.71(19), C(12)–Ir(1)–P(3) 92.3(2), C(1)–
Ir(1)–P(3) 133.50(18), P(1)–Ir(1)–P(3) 105.73(6), C(12)–Ir(1)–P(2)
97.26(19), C(1)–Ir(1)–P(2) 125.14(19), P(1)–Ir(1)–P(2) 110.73(6), P(3)–
Ir(1)–P(2) 97.79(6), C(1)–P(1)–C(6) 114.6(3), C(1)–P(1)–S(1) 118.5(2),
C(6)–P(1)–S(1) 110.7(2), C(1)–P(1)–Ir(1) 54.2(2), C(2)–C(1)–P(1)
137.0(5), P(1)–C(1)–Ir(1) 79.1(3).
its reaction with either elemental sulfur or selenium leads to
oxidation of the same phosphorus centre to give 8 and 9
respectively. It is worth noting that 7 is indefinitely stable in
solution and therefore does not undergo a 1,2-methyl migration
similar to the 1,2-hydrogen migrations that occur for 5a–c.
The 31P{1H} NMR spectra of 7–9 all show virtual triplet
resonances corresponding to the metallophosphirene phos-
phorus centres at significantly lower field (7 δ Ϫ125.5 ppm,
8 δ Ϫ86.1 ppm, 9 δ Ϫ117.4 ppm) than the related resonances
seen for both 3 and 5. This observation reflects the relatively
electron poor nature of the phosphorus centres in the former
compounds. In addition, the 13C NMR spectra of 7–9 display
low field signals (7 δ 330.4 ppm, 8 δ 371.3 ppm, 9 δ 341.2 ppm)
corresponding to the carbon centres double bonded to iridium.
The structure of the cation of 7 and the molecular structure
of 8 (Fig. 3 and 4) both show geometries at the iridium centre
similar to those in 3 and 5. Moreover, their P(1)–C(1) bond
lengths [7 1.738(5) Å, 8 1.746(6) Å] and Ir(1)–C(1) distances
[7 1.932(4) Å, 8 1.945(6) Å] are close to those in 3 and 5 and
their Ir(1)–P(1) interactions [7 2.3280(11) Å, 8 2.3552(17) Å] are
comparable to those in 5 but significantly shorter than in 3, as
would be expected. Finally, the P(1)–S(1) distance in 8 [1.992(2)
Å] is in the normal range for double bonds between these two
elements.11
Conclusions
In conclusion, the reactivity of an iridaphosphirene complex,
3, toward a variety of electrophiles has been investigated. In
all cases reaction occurs at the phosphorus centre of the
3-membered ring and not the metal centre. The protonated
complexes, 5a–c, slowly undergo irreversible 1,2-hydrogen shifts
to yield cationic iridium()–phosphaalkene complexes from
which the phosphaalkene can be liberated by treatment with
CO. A number of analogies between the structure, bonding and
reactivity of 3 and those of metallocyclopropene complexes
have been identified and discussed.
Experimental
General remarks
All manipulations were carried out using standard Schlenk and
glove box techniques under an atmosphere of high purity argon
or dinitrogen. The solvents diethyl ether, THF, toluene and
hexane were distilled over either potassium or Na/K alloy then
freeze/thaw degassed prior to use. Dichloromethane was dis-
tilled from CaH2. 1H, 13C and 31P NMR spectra were recorded
on either Bruker DPX400 or Jeol Eclipse 300 spectrometers in
Fig. 3 Structure of cationic component of compound 7. Selected
bond lengths (Å) and angles (Њ): Ir(1)–C(1) 1.932(4), Ir(1)–P(1)
2.3280(11), Ir(1)–P(2) 2.3903(11), Ir(1)–P(3) 2.3630(13), Ir(1)–C(13)
1.888(5), P(1)–C(1) 1.738(5), P(1)–C(6) 1.821(5), P(1)–C(7) 1.845(5),
C(13)–O(1) 1.138(5), C(1)–C(2) 1.521(6), C(13)–Ir(1)–C(1) 98.7(2),
C(13)–Ir(1)–P(1) 144.71(15), C(1)–Ir(1)–P(1) 47.03(14), C(13)–Ir(1)–
P(3) 96.16(15), C(1)–Ir(1)–P(3) 122.96(13), P(1)–Ir(1)–P(3) 109.44(4),
C(13)–Ir(1)–P(2) 89.11(14), C(1)–Ir(1)–P(2) 137.78(13), P(1)–Ir(1)–P(2)
110.64(4), P(3)–Ir(1)–P(2) 96.97(4), C(1)–P(1)–C(6) 115.0(2), C(1)–
P(1)–C(7) 119.7(2), C(1)–P(1)–Ir(1) 54.43(15), C(2)–C(1)–P(1) 137.7(4),
P(1)–C(1)–Ir(1) 78.54(18).
1
deuterated solvents and were referenced to the residual H or
13C resonances of the solvent used (1H and 13C NMR)
or external 85% H3PO4, 0.0 ppm (31P NMR). 13C NMR spectra
of all compounds were complicated by overlapping multiplets
in the aliphatic and aromatic regions and these signals could
not be confidently assigned. The resonances due to the Ir᎐C
᎐
carbon centre were too weak to be observed in 5. Mass spectra
D a l t o n T r a n s . , 2 0 0 3 , 2 8 8 9 – 2 8 9 3
2891

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Table 1 Crystal data for compounds 5a, 5bؒC7H8ؒCF3CO2H, 6ؒEt2O, 7 and 8ؒ2C7H8
5a
5bؒC7H8ؒCF3CO2H
6ؒEt2O
7
8ؒ2C7H8
Chemical formula
Fw
Crystal system
Space group
a/Å
b/Å
c/Å
α/Њ
C49H51F3IrO4P3S
1078.07
Monoclinic
P21/c
16.616(3)
15.143(3)
18.633(4)
90
97.30(3)
90
4650.4(16)
4
C59H60F6IrO5P3
1248.18
C52H61BF4IrO2P3
1089.93
Orthorhombic
Pnma
19.183(4)
16.407(3)
15.806(3)
90
C49H53IIrOP3
1069.92
Orthorhombic
P212121
14.369(3)
15.828(3)
19.492(4)
90
C62H66IrOP3S
1144.32
Monoclinic
P21/c
12.675(3)
37.548(8)
12.036(2)
90
111.17(3)
90
5341.6(18)
4
Triclinic
¯
P1
10.767(2)
14.326(3)
18.809(4)
76.13(3)
84.30(3)
84.07(3)
2793.2(10)
2
β/Њ
90
90
90
90
γ/Њ
V/Å3
4974.7(17)
4
4433.1(15)
4
Z
T /K
150(2)
3.07
59497
8076 (0.1318)
0.0560
150(2)
2.54
43499
10961 (0.0957)
0.0542
150(2)
2.83
85374
5892 (0.03977)
0.0547
150(2)
3.85
47718
10064 (0.0621)
0.0293
150(2)
2.67
70879
9740 (0.1108)
0.0475
µ(Mo-Kα)/mmϪ1
Reflections collected
Unique reflections (Rint
R1 (I > 2σ(I ))
wRЈ2 (all data)
)
0.1096
0.1404
0.1258
0.0594
0.1051
were recorded using a VG Fisons Platform II instrument under
APCI (atmospheric pressure chemical ionisation) conditions.
FAB mass spectra were obtained from the EPSRC Mass
Spectrometry Service, Swansea University. Melting points were
determined in sealed glass capillaries under argon, and are
uncorrected. The microanalysis was obtained from the
Warwick Microanalytical Service. Where reproducible micro-
analyses could not be obtained the NMR spectra of the
samples suggested their purity was greater than 95%. The
starting material, compound 3 was prepared by the literature
procedure.10 All other reagents were used as received.
allowed to stand at 25 ЊC for 7 days after which time it was
layered with hexane (10 cm3) to yield orange prisms of 6 over-
1
night. (0.028 g, 93%), m.p. 183–185 ЊC; NMR: H (400 MHz,
CD2Cl2, 300 K) δ 0.70–2.04 (m, 11H, Cy), 0.82 (s, 9H, But),
2
7.23–7.58 (m, 30H, ArH), 7.65 (d, 1H, P᎐CH, J = 23 Hz);
᎐
PH
31P{1H} (121.7 MHz, CD2Cl2, 300 K) δ 15.2 (d, 2 PPh3, 2JPP = 51
Hz), 222.4 (t, P᎐C, 2JPP = 51 Hz); IR (Nujol, ν/cmϪ1) 2006 (s, CO
᎐
str.); MS FAB (Noba matrix): m/z: 745 [Ir(CO)(PPh3)2ϩ, 40%],
715 [Ir(PPh3)2ϩ, 55%], 263 [PPh3Hϩ, 100%].
[Ir{᎐C(But)P(Me)(Cy)}(CO)(PPh ) ]I 7
᎐
3
2
To a solution of 3 (0.10 g, 0.11 mmol) in THF (10 cm3) at Ϫ78
ЊC was added MeI (0.12 mmol) in THF (5 cm3) over 5 min. The
resulting solution was warmed to room temperature, stirred
for 4 h after which time volatiles were removed in vacuo. The
residue was washed with hexane, dissolved in CH2Cl2 (ca.
1 cm3) and layered with hexane to afford red prisms of 7 over-
[Ir{᎐C(But)P(H)(Cy)}(CO)(PPh ) ][CF SO ] 5a
᎐
3
2
3
3
To a solution of 3 (0.10 g, 0.11 mmol) in diethyl ether (10 cm3)
at Ϫ78 ЊC was added HSO3CF3 (0.12 mmol) in diethyl ether
(5 cm3) over 5 min. The resulting solution was warmed to room
temperature, stirred for 4 h after which time volatiles were
removed in vacuo. The residue was washed with hexane, dissol-
ved in CH2Cl2 (ca. 1 cm3) and layered with hexane to afford
orange prisms of 5a overnight. (0.06 g, 52%), m.p. 183–185 ЊC;
NMR: 1H (400 MHz, CD2Cl2, 300 K) δ 0.70–2.03 (m, 11H, Cy),
1.52 (s, 9H, But), 7.02–7.53 (m, 30H, ArH), PH resonance not
observed; 31P{1H} (121.7 MHz, CD2Cl2, 300 K) δ Ϫ142.7 (v.t.
1
night. (0.075g, 70%), m.p. 216–218 ЊC; NMR: H (400 MHz,
C6D6, 300 K) δ 0.85–2.08 (m, 11H, Cy), 1.18 (d, 3H, PMe, 2JPH
= 12 Hz), 1.53 (s, 9H, But), 6.99–7.46 (m, 30H, ArH); 13C (101.6
MHz, CD Cl , 300 K) δ 178.3 (m, CO), 330.4 (m, Ir᎐C);
᎐
2
2
31P{1H} (121.7 MHz, CD Cl , 300 K) δ Ϫ121.4 (v.t., Ir᎐CP, 2J
᎐
2
2
PP
= 31 Hz), 4.8 (v.t., PPh3, 2JPP = 31 Hz), 8.9 (v.t., PPh3, 2JPP = 31
Hz); IR (Nujol, ν/cmϪ1) 1992 (s, CO str.); MS FAB (Noba
matrix): m/z: 944 [Mϩ Ϫ I, 12%], 650 [Mϩ Ϫ (I ϩ CO), 100%];
Acc. mass ESϩ: calc. for [Mϩ Ϫ I] 943.2948, found 943.2942;
elemental analysis, found: C 54.03, H 5.01, C49H53IIrOP3
requires C 55.00, H 4.99.
2
2
(virtual triplet), Ir᎐CP, J = 32 Hz), 8.0 (v.t., PPh3, JPP = 32
᎐
PP
Hz), 9.6 (v.t., PPh3, JPP = 32 Hz); IR (Nujol, ν/cmϪ1) 2003 (s,
2
CO str.), 2350 (m, PH str.); MS FAB (Noba matrix): m/z: 900
[Mϩ Ϫ (CO ϩ CF3SO3), 70%].
[Ir{᎐C(But)P(H)(Cy)}(CO)(PPh ) ][X] X ؍ CF CO 5b,
᎐
3
2
3
2
BF4 5c
[Ir{᎐C(But)P(᎐S)(Cy)}(CO)(PPh ) ] 8
᎐
᎐
3
2
Compounds 5b and 5c were prepared in a similar fashion to 5a.
5b: (yield 60%), m.p. 73–75 ЊC; NMR: 1H (400 MHz,
C7D8, 300 K) δ 0.70–2.03 (m, 11H, Cy), 1.47 (s, 9H, But),
7.02–7.87 (m, 30H, ArH), PH resonance not observed; 31P{1H}
A solution of 3 (0.10 g, 0.11 mmol) in toluene (10 cm3) was
added to a suspension of sulfur (0.15 mmol) in toluene (10 cm3)
at 25 ЊC and the resulting solution stirred for 3 h. Concentration
of this solution in vacuo to ca. 5 cm3 and cooling overnight to
Ϫ30 ЊC afforded red prisms of 8. (0.074g, 72%), m.p. 104–106
(121.7 MHz, C D , 300 K) δ Ϫ139.2 (v.t., Ir᎐CP, 2JPP = 32 Hz),
᎐
7
8
2
2
1
5.70 (v.t., PPh3, JPP = 32 Hz), 13.2 (v.t., PPh3, JPP = 32 Hz);
IR (Nujol, ν/cmϪ1) 2013 (s, CO str.), 2340 (m, PH str.); MS
FAB (Noba matrix): m/z: 930 [Mϩ – CF3CO2 100%].
ЊC; NMR: H (400 MHz, C6D6, 300 K) δ 0.66–2.38 (m, 11H,
Cy), 1.82 (s, 9H, But), 7.29–7.78 (m, 30H, ArH); 13C (101.6
MHz, CD Cl , 300 K) δ 183.3 (m, CO), 371.3 (m, Ir᎐C);
᎐
2
2
5c: (yield 50%), m.p. 169–171 ЊC; NMR: 1H (400 MHz,
CD2Cl2, 300 K) δ 0.79–1.87 (m, 11H, Cy), 1.53 (s, 9H, But),
31P{1H} (121.7 MHz, CD Cl , 300 K) δ Ϫ86.1 (v.t., Ir᎐CP, 2J
᎐
2
2
PP
= 27 Hz), 9.1 (v.t., PPh3, 2JPP = 27 Hz), 13.5 (v.t., PPh3, 2JPP = 27
Hz); IR (Nujol, ν/cmϪ1) 1983 (s, CO str.); MS APCI: m/z: 961
[MHϩ, 100%], 263 [PPh3Hϩ, 75%].
6.99–7.67 (m, 30H, ArH), PH resonance not observed; 31P{1H}
2
(121.7 MHz, CD Cl , 300 K) δ Ϫ142.9 (v.t., Ir᎐CP, J = 32
᎐
2
2
PP
2
2
Hz), 8.20 (v.t., PPh3, JPP = 32 Hz), 9.43 (v.t., PPh3, JPP = 32
Hz); IR (Nujol, ν/cmϪ1) 2014 (s, CO str.), 2370 (m, PH str.); MS
FAB (Noba matrix): m/z: 930 [Mϩ Ϫ BF4, 25%].
[Ir{᎐C(But)P(᎐Se)(Cy)}(CO)(PPh ) ] 9
᎐
᎐
3
2
To a solution of 3 (0.10 g, 0.11 mmol) in toluene (10 cm3) at 25
ЊC was added selenium powder (0.15 mmol). The resulting
suspension was stirred for 3 h and filtered. Concentration of the
filtrate in vacuo to ca. 5 cm3 and cooling overnight to Ϫ30 ЊC
[Ir(CO)(PPh ) {ꢀ1-P(Cy)᎐C(H)(But)}][BF ] 6
᎐
3
2
4
A solution of 5c (0.030 g, 0.03 mmol) in CH2Cl2 (2 cm3) was
D a l t o n T r a n s . , 2 0 0 3 , 2 8 8 9 – 2 8 9 3
2892

View Article Online
afforded black prisms of 9. (0.044g, 40%), m.p. 95–97 ЊC;
Thanks also go to the EPSRC Mass Spectrometry Service,
Swansea, for FAB mass spectra.
1
NMR: H (400 MHz, C6D6, 300 K) δ 0.60–2.32 (m, 11H, Cy),
1.86 (s, 9H, But), 7.00–7.95 (m, 30H, ArH); 13C (101.6 MHz,
CD Cl , 300 K) δ 189.8 (m, CO), 341.2 (m, Ir᎐C); 31P{1H}
᎐
2
2
References
(121.7 MHz, CD Cl , 300 K) δ Ϫ117.4 (v.t., Ir᎐CP, 2JPP = 28 Hz,
᎐
2
2
1JSeP = 653 Hz), 7.1 (v.t., PPh3, JPP = 27 Hz), 14.5 (v.t., PPh3,
2JPP = 27 Hz); IR (Nujol, ν/cmϪ1) 1974 (s, CO str.); MS APCI:
m/z: 1008 [MHϩ, 100%].
2
1 D. S. Frohnapfel and J. L. Templeton, Coord. Chem. Rev., 2000,
206–207, 199 and references therein.
2 C. P. Casey, J. T. Brady, T. M. Boller, F. Weinhold and R. K.
Hayashi, J. Am. Chem. Soc., 1998, 120, 12500.
3 P. Legzdins, S. A. Lumb and S. J. Rettig, Organometallics, 1999, 18,
3128.
4 C. Jones and A. F. Richards, J. Chem. Soc., Dalton Trans., 2000,
3233.
5 C. Jones and A. F. Richards, J. Organomet. Chem., 2001, 629, 109.
6 C. Jones, J. A. Platts and A. F. Richards, Chem. Commun., 2001, 663.
7 C. Jones, P. C. Junk, A. F. Richards and M. Waugh, New J. Chem.,
2002, 26, 1209.
8 S. Aldridge, C. Jones, P. C. Junk, A. F. Richards and M. Waugh,
J. Organomet. Chem., 2003, 665, 127.
9 C. Jones, A. F. Richards, S. Fritzsche and E. Hey-Hawkins,
Organometallics, 2002, 21, 438.
10 M. Brym, C. Jones and A. F. Richards, J. Chem. Soc., Dalton Trans.,
2002, 2800.
Structure determinations
Crystals of 5a, 5bؒCF3CO2HؒC7H8, 6ؒEt2O, 7 and 8ؒ2C7H8
suitable for X-ray structure determination were mounted in
silicone oil. Crystallographic measurements were made using a
Nonius Kappa CCD diffractometer. The structures were solved
by direct methods and refined on F 2 by full matrix least squares
(SHELX97 15) using all unique data. Crystal data, details of
data collections and refinements are given in Table 1. The
molecular structures of the complexes are depicted in Fig. 1–4
and show ellipsoids at the 30% probability level.
CCDC reference numbers 208255–208259.
See http://www.rsc.org/suppdata/dt/b3/b304076n/ for crystal-
lographic data in CIF or other electronic format.
11 Determined from a survey of the Cambridge Crystallographic
Database, CCDC, Cambridge, March, 2003.
12 G. Brauers, F. J. Feher, M. Green, J. K. Hogg and A. G. Orpen,
J. Chem. Soc., Dalton Trans., 1996, 3387.
13 M. Brym, C. Jones and M. Waugh, New J. Chem., submitted for
publication.
14 H. Lee, J. Bae, J. Ko, Y. S. Kang, H. S. Kim, S. Kim, J. Chung and
S. O. Kang, J. Organomet. Chem., 2000, 614, 83.
15 G. M. Sheldrick, SHELXL-97, Program for refinement of crystal
structures, University of Göttingen, Germany, 1997.
Acknowledgements
We gratefully acknowledge financial support from EPSRC
(studentship for MB and postdoctoral fellowship for MW).
D a l t o n T r a n s . , 2 0 0 3 , 2 8 8 9 – 2 8 9 3
2893