Stabilisation of iridium(III) fluoride complexes with NHCs

Article abstract of DOI:10.1039/c0dt00857e

The first neutral, [IrClF₂(NHC)(COD)] and [IrClF ₂(CO)₂(NHC)] (NHC = IMes, IPr), and cationic, [IrF ₂py(IMes)(COD)][BF₄] and [IrF₂L(CO) ₂(NHC)][BF₄] (NHC = IMes, L = PPh₂Et, PPh ₂CCPh, py; NHC = IPr, L = py), NHC iridium(iii) fluoride complexes, have been synthesised by the xenon difluoride oxidation of iridium(i) substrates. The stereochemistries of these iridium(iii) complexes have been confirmed by multinuclear NMR spectroscopy in solution and no examples of fluoride-trans-NHC arrangements were observed. Throughout, CO was found to be a better co-ligand for the stabilisation of the iridium(iii) fluoride complexes than COD. Attempts to generate neutral trifluoroiridium(iii) complexes, [IrF₃(CO)(NHC)], via the ligand substitution reaction of [IrF ₃(CO)₃] with the free NHCs were unsuccessful. The Royal Society of Chemistry 2010.

Full text of DOI:10.1039/c0dt00857e

View Article Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/dalton | Dalton Transactions
Stabilisation of iridium(III) fluoride complexes with NHCs†‡
John Fawcett, Duncan A. J. Harding, Eric G. Hope,* Kuldip Singh and Gregory A. Solan
Received 16th July 2010, Accepted 3rd September 2010
DOI: 10.1039/c0dt00857e
The first neutral, [IrClF2(NHC)(COD)] and [IrClF2(CO)2(NHC)] (NHC = IMes, IPr), and cationic,
[IrF2py(IMes)(COD)][BF4] and [IrF2L(CO)2(NHC)][BF4] (NHC = IMes, L = PPh2Et, PPh2CCPh, py;
NHC = IPr, L = py), NHC iridium(III) fluoride complexes, have been synthesised by the xenon
difluoride oxidation of iridium(I) substrates. The stereochemistries of these iridium(III) complexes have
been confirmed by multinuclear NMR spectroscopy in solution and no examples of
fluoride-trans-NHC arrangements were observed. Throughout, CO was found to be a better co-ligand
for the stabilisation of the iridium(III) fluoride complexes than COD. Attempts to generate neutral
trifluoroiridium(III) complexes, [IrF3(CO)(NHC)], via the ligand substitution reaction of [IrF3(CO)3]
with the free NHCs were unsuccessful.
Introduction
Results and discussion
There has been growing interest in the area of organometallic
fluoride complexes as a result of the synthetic challenges and
potential applications, such as in aryl-F bond formation, of
such species. Indeed, the development of more reliable synthetic
procedures for the synthesis of late transition metal fluoride
coordination and organometallic complexes over the past
10–15 years has led to considerable growth in the total number
of examples, in the variation in ligand donor sets and in the
appreciation of the criteria for M–F bond stabilisation.1–8
Throughout most of these studies, phosphine, N-donor or s-aryl
ligands have routinely been included in the first coordination
sphere to aid product stabilisation and characterisation. In
contrast, although the coordination chemistry of N-heterocyclic
carbenes (NHCs) has been extensively investigated,9 reports of late
transition metal-fluoride-NHC complexes had been restricted to
only monofluorides [AuF(NHC)],10 [RuFH(CO)2(NHC)2],11
(a) Ligand displacement reactions with [IrF3(CO)3]
Phosphine ligands undergo facile reactions with [IrF3(CO)3],8
however, in contrast to the air- and moisture-stable ruthenium(II)
and osmium(II) fluoride complexes [MF2(CO)2(phosphine)2],16 the
iridium(III) products, [IrF3(CO)(phosphine)2], rapidly decompose
in solution and in the solid state, even at low temperatures.8 N-
heterocyclic carbenes (NHCs), in view of the improved s-donor
and differing steric properties, provide alternative supporting
ligands that might confer additional stability on this class of
complex. Unfortunately, attempts to react [IrF3(CO)3] with either
the free NHCs, IMes or IPr, or their imidazolium precursors in
the presence of base were unsuccessful, affording complicated
mixtures of products, as evidenced by in situ NMR spectroscopy,
that rapidly decomposed to insoluble black precipitates even at
low temperatures, possibly as a consequence of the steric bulk of
these ligands. In light of the failure to use ligand metathesis for the
synthesis of iridium(III)-fluoride-NHC complexes, we turned our
attention to our second, oxidative addition, route (Scheme 1).
We,8 and others,17 have shown that XeF2 readily oxidises a
variety of neutral and cationic iridium(I) phosphine complexes
containing carbonyl, halide and/or COD (1,5-cyclooctadiene) to
form iridium(III) difluoride complexes. Since, monosubstituted
neutral and cationic complexes of iridium(I), particularly those
with COD or CO ligands, are amongst the most extensively
investigated metal carbene derivatives,18 these provided an ideal
series for our investigation.
[RuFH(CO)(NHC)(PPh3)2]12
and
[NiF(ArF)(NHC)2],13,14
until our recent report of the first difluoride complexes
[RuF2(CO)2(NHC)2].15
We have recently developed two synthetic routes to iridium(III)
phosphine and pyridine fluoride complexes, either by ligand
substitution reactions at [IrF3(CO)3] or oxidation of iridium(I)
complexes with xenon difluoride.8 In view of the recent reports
of metal-fluoride-NHC complexes we surmised that iridium(III)
N-heterocyclic carbene fluoride complexes might be accessible
via one or both of these routes. Herein, we report the results
of these investigations, including the synthesis of a range of
neutral and cationic iridium(I) NHC complexes as intermediates
in the syntheses of the first examples of iridium(III)-fluoride-NHC
complexes.
(b) Synthesis of iridium(I) starting materials
Neutral [IrCl(NHC)(COD)] {NHC = IMes = N,N¢-bis(2,4,6-
trimethylphenyl)imidazol-2-ylidene (1), NHC = IPr = N,N¢-
bis(2,6-diisopropylphenyl)imidazol-2-ylidene (2)} and cis-
[IrCl(CO)2(NHC)] {NHC = IMes (3), NHC = IPr (4)} were
prepared by the literature routes.18 Chloride abstraction from
1 and introduction of P(nBu)3 has previously been used to
generate a cationic Ir(I) derivative for evaluation as an olefin
hydrogenation catalyst.19 In this work, the steric impact of
Department of Chemistry, University of Leicester, Leicester, UK LE1 7RH.
E-mail: egh1@le.ac.uk; Fax: +44 116 252 3789
† This publication is part of the web themed issue on fluorine chemistry.
‡ CCDC reference numbers 723140–723144. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/c0dt00857e
This journal is
The Royal Society of Chemistry 2010
Dalton Trans., 2010, 39, 10781–10789 | 10781
©

View Article Online
Scheme 1
the NHC ligands here is significant where only decomposition
products were obtained in the reaction of (1) with PPh3 in the
presence of AgBF4, whilst addition of ethyldiphenylphosphine,
phenylethynyldiphenylphosphine or pyridine generated the new
[Ir(IMes)L(COD)]+[BF4]- [(5), (6) and (7)] respectively in good
yields (Scheme 1). In contrast, only the pyridine adduct 8 could be
isolated in the analogous elimination reactions with 2 containing
the bulkier IPr ligand. We note that both pyridine adducts, as their
Ir–L angle is wider resulting in considerable asymmetry in the
Ir–CCOD bond lengths and bond angles, presumably as a result of
a steric clash arising from the phenylethynyl group.
Displacement of COD by CO occurs readily in the quantitative
formation of [Ir(NHC)(CO)2L]+[BF4]- [NHC = IMes, L = PPh2Et,
PPh2CCPh, py (9–11); NHC = IPr, L = py (12)] (Scheme 1). All
four complexes have two IR active u(CO) absorptions in their IR
spectra but subtle variations in the 1H NMR data for the ortho-Me
protons in the IMes ligands suggest differences in their structures,
that were confirmed by X-ray crystallographic studies for 9 and
11 for crystals grown either by slow evaporation of a saturated
dichloromethane solution of 9 or by slow vapour diffusion of
hexane into a saturated dichloromethane solution of 11. Views of
the complexes are shown in Figs. 4 and 5 and selected bond lengths
and angles are collected in Table 2. The structural determinations
reveal very similar Ir–Ccarbene, Ir–Ccarbonyl and C–O bond distances,
but [Ir(IMes)(CO)2(PPh2Et)][BF4] (9) adopts a distorted trans
stereochemistry whilst [Ir(IMes)(CO)2(py)][BF4] (11) displays a
regular cis stereochemistry. For 9, the two CO molecules are
undergoing a distinct out-of-plane deformation, as reflected by the
C(1)–Ir(1)–C(2) angle [150.7(4)◦], and the C(3)–Ir(1)–P(1) angle
[168.95(18)◦] is substantially smaller than linear. These distortions
create a sterically unencumbered ‘pocket’ into which the CO
molecules are directed. For 11, the integrity of the square plane
is reflected in the C1–Ir–C3 and N3–Ir–C1 angles [91.89(17)◦ and
176.63(18)◦]. The molecular structure reveals that the pyridine ring
-
PF6 salts, have previously been reported from the displacement
of pyridine in [Ir(py)2(COD)]+[PF6]- with NHCs.22 Complexes
5–8 have been characterised by multinuclear NMR spectroscopic
studies, mass spectrometry, elemental analysis and for 5, 6 and
8 by X-ray crystallographic studies for crystals grown by careful
layering of dichloromethane–hexane solutions.
Views of the complexes are shown in Figs. 1–3 and se-
lected bond lengths and angles are collected in Table 1. For
[Ir(IPr)py(COD)]+[BF4]- (8), the asymmetric unit contains two
unique metal cations, two unique anions and three lattice
dichloromethane molecules. The metal-carbene bond lengths for
the three complexes are virtually identical and unremarkable.23
The Ir-COD bond lengths within each complex are not sta-
tistically different and the Ir-CODtrans-L distances for the two
phosphine adducts are significantly longer than those for the
pyridine adducts, in line with their relative donor properties. The
only substantive differences within the structures concerns the
phenylethynyldiphenylphosphine adduct (7) for which the Ccarbene
–
10782 | Dalton Trans., 2010, 39, 10781–10789
This journal is
The Royal Society of Chemistry 2010
©

View Article Online
◦
˚
Table 1 Selected bond lengths (A) and angles ( ) for (5), (6), (8) and [Ir(IPr)(py)(COD)][PF6]
(5)
(6)
(8)
[Ir(IPr)(py)(COD)][PF6]25
Ir(1)–C(carbene)
Ir(1)–C(CODtrans-carbene
Ir(1)–C(CODtrans-carbene
Ir(1)–C(CODtrans-L
Ir(1)–C(CODtrans-L
Ir(1)–N(3)
2.077(5)
2.200(5)
2.177(5)
2.204(5)
2.197(5)
2.063(3)
2.248(3)
2.157(3)
2.213(3)
2.176(3)
2.076(4)
2.194(4)
2.178(4)
2.143(5)
2.126(4)
2.103(4)
2.077(4)
2.187(4)
2.175(4)
2.146(4)
2.117(4)
2.106(3)
2.080(10)
2.217(11)
2.193(11)
2.216(11)
2.131(10)
2.081(9)
)
)
)
)
Ir(1)–P(1)
C–C(CODtrans-carbene
C–C(CODtrans-L
N(1)–C(carbene)
N(2)–C(carbene)
Av B–F
2.3575(12)
1.402(7)
1.402(7)
1.375(5)
1.374(5)
2.3030(9)
1.393(5)
1.406(4)
1.369(4)
1.364(4)
1.358
)
1.393(7)
1.402(7)
1.357(5)
1.377(5)
1.358
1.402(7)
1.397(6)
1.371(5)
1.365(5)
1.358
1.408(15)
1.383(14)
—
—
—
)
1.379
C(carbene)–Ir(1)– C(CODtrans-carbene
C(carbene)–Ir(1)– C(CODtrans-carbene
C(CODtrans-L)–Ir(1)–L
C(CODtrans-L)–Ir(1)–L
C(carbene)–Ir(1)–L
)
)
168.74(17)
153.78(18)
167.30(15)
154.45(15)
94.12(13)
175.19(11)
141.02(12)
171.94(9)
136.26(9)
98.30(9)
162.86(18)
159.84(18)
160.26(18)
158.80(17)
96.12(15)
161.08(17)
160.89(18)
160.45(15)
158.46(16)
97.63(14)
165.4(4)
157.1(4)
159.5(4)
159.5(4)
95.4(4)
Fig. 2 Molecular structure of the cationic unit in 6 with 30% displacement
-
ellipsoids. H atoms and BF4 anion have been omitted for clarity.
methyl group to the pyridine ring. A previous study has shown
that a coordinated pyridine may significantly shift the proton
resonances of proximal groups.24 Although there is a scarcity of
structural data for mixed NHC/phosphine carbonyl complexes
in the literature, there is precedent for a trans relationship of an
NHC and a metal-bound carbonyl in the related complexes trans-
[RhCl(IMes)(CO)(PPh3)]25 and [IrCl(Ibiox6)(CO)2].26 Whilst the
stereochemistry of 10 and 12 is not unequivocal in the absence
of structural characterisations, in light of the similarity of the
spectroscopic data for 9 and 10, and between 11 and 12, we assign
a trans-stereochemistry to the phenylethynyldiphenylphosphine
adduct 10 and a cis-stereochemistry to the IPr-py complex 12.
Fig. 1 Molecular structure of the cationic unit in 5 with 30% displacement
ellipsoids. H atoms and BF4 anion have been omitted for clarity.
-
is aligned parallel with the diametrically opposed mesityl ring. The
N(2)–C(3)–Ir(1)–N(3) torsion angle [45.8◦] indicates that it does
not lie orthogonal to the plane of the imidazolium ring, rather
there is a slight twist down the N(3)–Ir(1)–C(1) axis, such that the
centroid of the pyridine ring is oriened towards the methyl group of
C(23). Similarly, the carbene has undergone a mild twist down the
C(3)–Ir(1)–C(2) axis such that the heterocycle bisects the C(2)–
Ir(1)–C(1) plane, but does not lie orthogonal to it. This places
the two mesityl groups of the carbene in close proximity to the
pyridine ring (on one side) and the C(1)–O(1) unit (on the other).
It is plausible that the highfield shift of the ortho-mesityl protons
observed for 11 may be related to this proximity of the C(23)
(c) Oxidation of [IrCl(NHC)(COD)] and [IrCl(CO)2(NHC)] with
XeF2
The neutral iridium(I) NHC-chloride complexes 1–4 can be readily
oxidised by XeF2 in solution at low temperatures to afford the
first iridium(III) NHC-fluoride complexes, [IrClF2(NHC)(COD)]
[NHC
=
IMes (13); IPr (14)}] and [IrClF2(CO)2(NHC)]
This journal is
The Royal Society of Chemistry 2010
Dalton Trans., 2010, 39, 10781–10789 | 10783
©

View Article Online
◦
˚
Table 2 Selected bond lengths (A) and angles ( ) for (9), (11)
(9)
(11)
Ir(1)–C(1)
Ir(1)–C(2)
Ir(1)–C(3)
Ir(1)–N(3)
1.864(8)
1.895(9)
2.071(6)
1.842(5)
1.894(5)
2.076(4)
2.112(4)
Ir(1)–P(1)
C(1)–O(1)
C(2)–O(2)
N(1)–C(3)
N(2)–C(3)
Av B–F
2.331(4)
1.164(9)
1.130(10)
1.351(8)
1.354(8)
1.367
1.132(6)
1.135(6)
1.361(6)
1.357(6)
1.379
C(1)–Ir(1)–C(2)
C(2)–Ir(1)–C(3)
C(1)–Ir(1)–N(3)
C(3)–Ir(1)–P(1)
150.7(4)
91.5(3)
91.0(2)
177.12(19)
176.63(18)
168.95(18)
for all four complexes revealed two, mutually-coupled, doublets.
The coupling constants are entirely consistent with previously
Fig. 3 Molecular structure of one of the unique cationic units of 8 with
30% displacement ellipsoids. H atoms, BF4 ions and lattice CH2Cl2 have
been omitted for clarity.
2
reported 2JFF interactions on iridium(III) {IrF3(CO)(PEt3)2 JFF
=
=
-
2
2
96 Hz; IrClF2(CO)(PEt3)2 JFF = 115 Hz; IrBrF2(CO)(PEt3)2 JFF
130 Hz}.17 The lower frequency chemical shifts, at ca. d -390,
are in the region diagnostic of F-trans-Cl on iridium(III) centres,
whilst the variation in chemical shifts for the high frequency
doublets for 15 and 16 vs. those of 13 and 14 suggests an F-
trans-CO arrangement for the former complexes,8,27,28 and an F-
trans-COD arrangement for the latter (Scheme 1). Although these
are the first examples of an iridium(III)-fluoride bound trans to an
olefin group, this is not an unreasonable assignment in relation to
the relative chemical shifts for the most closely related iridium(I)
compounds; [IrF(PPh3)(COD)]4 and [IrF(CO)(PPh3)2]29 d -219.3
and -254 respectively. As expected for such a conformation, the
olefinic resonances for the COD ligands are inequivalent, and at
ca. d 5.4 are substantially shifted from those for the iridium(I)
starting materials.
(d) Oxidation of [IrL(CO)2(NHC)][BF4] and
[IrL(NHC)(COD)][BF4] with XeF2
Fig. 4 Molecular structure of the cationic unit in 9 with 30% displacement
ellipsoids. H atoms and the BF4 anion have been omitted for clarity.
-
The iridium(I) carbonyl cations [Ir(IMes)(CO)2L]+[BF4]- [L =
PPh2Et (9), PPh2CCPh (10)] react similarly with XeF2 in
solution to generate, approximately, 1 : 1 mixtures of two iso-
meric difluoride complexes [IrF2(CO)2(IMes)L]+[BF4]- (17, 18)
(Scheme 1; Table 3) in which the NHC-trans-phosphine ar-
rangement of the starting materials are maintained. Related,
approximately, 1 : 1 mixtures of isomeric difluoride complexes
[IrF2(CO)2(NHC)py]+[BF4]- (19, 20) (Scheme 1; Table 3) are
formed in the oxidation of [Ir(NHC)(CO)2py]+[BF4]- [NHC =
IMes (11), IPr (12)]. Similar mixtures of isomeric fluorides are
formed in the oxidation of [Ir(CO)2(phosphine)2]+[BF4]- with
XeF2.8 Both the absolute and relative values of the 19F NMR
2
resonances and the JPF coupling constants are diagnostic of the
Fig. 5 Molecular structure of the cationic unit in 11 with 30% displace-
ment ellipsoids. H atoms and BF4 anion have been omitted for clarity.
-
F-trans-F and F-trans-CO arrangements on iridium(III); in line
with the oxidations of the neutral iridium(I) NHC complexes (vide
supra) we find no evidence for F-trans-NHC arrangements for
these products. As indicated earlier, the reduction in stability in
moving from CO to COD in this work hampered our studies on
the oxidation of the [Ir(NHC)L(COD)]+ cations (5–8). In all cases,
xenon evolution was seen on warming the reaction mixtures to ca
-80 ◦C, but this was accompanied by rapid decomposition. Only in
[NHC = IMes (15); IPr (16)] (Scheme 1). Full characterisation
was possible for 15 and 16 whilst 13 and 14 were identified
by NMR spectroscopy at low temperature and decomposed
rapidly at room temperature, supporting our earlier conclusion,8
that CO is a better ligand than COD for the stabilisation of
iridium(III)-fluoride complexes. The 19F NMR spectra (Table 3)
10784 | Dalton Trans., 2010, 39, 10781–10789
This journal is
The Royal Society of Chemistry 2010
©

View Article Online
Table 3 19F NMR data for iridium-NHC-fluoride complexes
d (ppm) (J/Hz)
F-trans-F
F-trans-Cl
F-trans-CO
F-trans-COD
-273.5 (141a)
-270.3 (147a)
[IrClF2(IMes)(COD)] (13)
[IrClF2(IPr)(COD)] (14)
-382.5 (141a)
-386.9 (147a)
-397.4 (121a)
-400.3 (123a)
[IrClF2(IMes)(CO)2] (15)
-311.3 (121a)
-307.9 (123a)
-328.6 (36b)
-335.0 (42b)
-318.9
[IrClF2(IPr)(CO)2] (16)
[IrF2(CO)2(IMes)(PEtPh2)]+ (17)
[IrF2(CO)2(IMes)(PPh2CCPh)]+ (18)
[IrF2(CO)2(IMes)(py)]+ (19)
[IrF2(CO)2(IPr)(py)]+ (20)
[IrF2(IMes)(COD)(py)]+ (21)
-521.8 (20b)
-517.3 (25b)
-455.1
-458.1
-425.2
-303.4
a
b
2JFF
. .
2JPF
the case of [IrF2(IMes)py(COD)]+[BF4]- (21) could reproducible
NMR spectra be obtained, for which the 19F data is diagnostic of
an F-trans-F stereochemistry (Table 3; Scheme 1).
Conclusions
A series of neutral and cationic iridium(I) NHC complexes have
been prepared and characterised. Oxidation of these complexes
with xenon difluoride in solution generates difluoroiridium(III)
complexes stabilised by NHC ligands. The stereochemistries have
been confirmed by multinuclear NMR spectroscopy in solution,
but in no cases were fluoride-trans-NHC arrangements adopted.
Throughout CO was found to be a better co-ligand for these
derivatives than COD. In contrast, ligand substitution reactions
of NHCs with [IrF3(CO)3] did not afford iridium-NHC-fluoride
complexes.
Each of these iridium(III)-NHC fluoride complexes decompose
inconsistently in solution in a few hours, always with loss of
the metal-bound fluoride resonances and generation of HF,
which precluded all our attempts to grow crystals suitable
for structural characterisation. However, crystallographic stud-
ies on one of the products, a C–H activated IMes complex,
2
[IrF(h -IMes)(CO)2(PPh2Et)]+[BF4]-, formed from decomposition
of [IrF2(CO)2(IMes)(PPh2Et)]+[BF4]- (17) in dichloromethane,
revealed insight into the decomposition process (Fig. 6). Unfortu-
nately, poor quality data precluded full anisotropic refinement
so we do not report here a full structural characterisation.
However, the analysis does clearly demonstrate a single Ir(III)–
F bond, the loss of one fluoride ligand and a cyclometalated IMes
ligand.30
Experimental
General remarks
All reactions, unless otherwise stated, were carried out under
an atmosphere of dry, oxygen-freed nitrogen, using standard
Schlenk line or metal vacuum line techniques31 or in a nitrogen
purged dry box. Solvents were distilled under nitrogen from
appropriate drying agents and degassed prior to use.32 1H, 19F
and 31P NMR spectroscopic studies were carried out on a
Bruker DPX300 spectrometer at 300.14, 282.41 and 121.50 MHz
respectively or a Bruker DRX400 spectrometer at 400.13, 376.46
and 161.98 MHz respectively and were referenced to external
SiMe4 (1H), external CFCl3 (19F) and to external H3PO4 (31P) using
the high frequency positive convention. Abbreviations for NMR
spectral multiplicities are as follows: s = singlet, d = doublet, m =
multiplet. Elemental analyses were performed by the Elemental
Analysis Service at the London Metropolitan University. Mass
spectra were recorded on a Kratos Concept 1H mass spectrometer.
IR spectra were recorded as solid samples on a Perkin Elmer
Spectrum One FT-IR spectrometer.
[IrCl(NHC)(COD)] and cis-[IrCl(CO)2(NHC)] (NHC = IMes,
NHC)18–21 were prepared by the literature routes.
(Ethyldiphenylphosphine)(1,3-bis{2,4,6-trimethylphenyl}imida-
zol-2-ylidene)(cyclo-octa-1,5-diene)iridium tetrafluoroborate (5).
A Schlenk tube was charged in the dry box with (1,3-
bis{2,4,6-trimethylphenyl}imidazol-2-ylidene)(cyclo-octa-1,5-
diene)iridium chloride19 (0.250 g, 0.390 mmol) and AgBF4 (84 mg,
0.429 mmol). THF (10 cm3) was transferred onto the solids via
cannular, and the resulting suspension stirred in the dark for 2 h.
Fig. 6 Molecular structure of the cationic unit in the cyclometallated
IMes complex [IrF(IMes)(CO)2(PPh2Et)]+[BF4]-. H atoms and BF4- anion
have been omitted for clarity.
This journal is
The Royal Society of Chemistry 2010
Dalton Trans., 2010, 39, 10781–10789 | 10785
©

View Article Online
The precipitated silver salts were filtered off, and a solution of
PPh2Et (83 mg, 0.390 mmol) in THF (10 cm3) added dropwise to
the stirred mother liquor. The resulting orange solution was stirred
for an additional two hours, and the solvent removed in vacuo. The
orange powder was recrystallized from DCM–hexane, giving the
product [Ir(COD)(IMes)(PPh2Et)]+[BF4]- (5) as an air-sensitive
orange powder (0.25 g; 71%). Anal. Calc. for C43H51BF4IrN2P: C,
56.98, H, 5.68, N, 3.09. Found: C, 56.94, H, 5.73, N, 3.01. nmax/cm-1
2927br, 1482br, 1381br, 1299(s, 1249 s, 1030br ([BF4]-), 746 s, 696s.
1H NMR (CDCl3): 7.40–6.90 (m, 16H, ArH and NCHCHN),
4.21 (br s, 2H, COD-CH), 2.91 (br s, 2H, COD-CH), 2.38 (s,
6H, ortho-CH3), 2.29 (s, 6H, ortho-CH3), 2.00 (s, 6H, para-CH3),
0.440 mmol) in DCM (5 cm3) at room temperature, after
which the solution was poured into diethylether (20 cm3). The
precipitate was collected and recrystallized from DCM–hexane
to afford the product [Ir(IMes)(CO)2(PPh2Et)]+[BF4]- (9) as
an air-sensitive orange powder (0.36 g, 96%). Anal. Calc. for
C37H39BF4IrN2O2P·0.5CHCl3: C, 49.28, H, 4.36, N, 3.07. Found:
C, 50.05, H, 4.34, N, 3.09. nmax/cm-1 2924w, 2069 s (CO),
1
1977 s (CO), 1608w, 1486 s, 1437 s, 1049vs ([BF4]-), 695s. H
NMR (CDCl3): 7.50–7.10 (m, 16H, ArH and NCHCHN), 2.50
2
(q, 2H, JPH
=
3JHH 7.9 Hz, PCH2), 2.33 (s, 6H, para-CH3),
3
3
2.10 (s, 12H, ortho-CH3), 0.95 (dt, 3H, JPH 12.8, JHH 7.9 Hz,
PCH2CH3). 19F{ H} NMR (CDCl3): -153.9 (s, [BF4]-). 31P{ H}
NMR (CDCl3): 10.6 (s, IrPPh2Et). m/z (FAB) 767 ([M-BF4]+),
739 ([M-CO-BF4]+).
1
1
2
1.94 (q, 2H, 3JHH = JPH 6.5 Hz, PCH2), 1.70–1.40 (m, 8H, COD-
3
3
1
CH2), 0.72 (dt, 3H, JPH 13.0, JHH 6.5 Hz, PCH2CH3). 19F{ H}
NMR (CDCl3): -153.4 (s, [BF4]-). 31P{ H} NMR (CDCl3): 11.3
1
(Phenylethynyldiphenylphosphine)(1,3-bis{2,4,6-trimethylphe-
nyl}imidazol-2-ylidene)(dicarbonyl)iridium tetrafluoroborate (10).
The title compound, an air-sensitive orange solid, was isolated in
a similar manner to that described for 9 (0.40 g, 98%). Anal. Calc.
for C43H39BF4IrN2O2P: C, 55.75, H, 4.25, N, 3.03. Found: C, 55.81,
H, 4.18, N, 2.97. nmax/cm-1 2918w, 2168 s (CC), 2078 s (CO), 1989 s
(CO), 1483 s, 1438 s, 1046 s ([BF4]-), 850 s, 752 s, 688s. 1H NMR
(CDCl3): 7.61–7.00 (m, 19H, ArH), 7.10 (s, 2H, NCHCHN),
(s, IrPPh2Et). m/z (FAB) 819 ([M-BF4]+), 711 ([M-COD-BF4]+),
605 ([M-PPh2Et-BF4]+).
(Phenylethynyldiphenylphosphine)(1,3-bis{2,4,6-trimethylphe-
nyl}imidazol-2-ylidene)(cyclo-octa-1,5-diene)iridium tetrafluoro-
borate (6). The title compound, an air-sensitive orange solid,
was isolated in a similar manner to that described for 5 (0.28 g,
73%). Anal. Calc. for C49H51BF4IrN2P: C, 60.16, H, 5.26, N,
2.86. Found: C, 60.02, H, 5.25, N, 2.86. nmax/cm-1 2917br,
2175 s (CCacetylene), 1608br, 1483w, 1437w, 1035 s ([BF4]-), 757 s,
690 s (Solid State). 1H NMR (CDCl3): 7.45–7.00 (m, 19H,
ArH), 6.62 (s, 2H, NCHCHN), 4.75 (br s, 2H, COD-CH),
3.17 (br s, 2H, COD-CH), 2.42 (s, 12H, ortho-CH3), 2.33 (s,
1
2.34 (s, 6H, para-CH3), 2.15 (s, 12H, ortho-CH3). 19F{ H} NMR
1
(CDCl3): -154.0 (s, [BF4]-). 31P{ H} NMR (CDCl3): -12.9 (s,
IrPPh2CCPh). m/z (FAB) 839 ([M-BF4]+), 811 ([M-CO-BF4]+),
783 ([M-2CO-BF4]+).
(Pyridine)(1,3-bis{2,4,6-trimethylphenyl}imidazol-2-ylidene)-
(dicarbonyl)iridium tetrafluoroborate (11). The title compound,
an air-sensitive yellow powder, was isolated in a similar man-
ner to that described for 9 (0.29 g, 92%). Anal. Calc. for
C28H29BF4IrN3O2: C, 46.77, H, 4.07, N, 5.85. Found: C, 46.81,
H, 4.18, N, 5.97. nmax/cm-1 2073 s (CO), 2006 s (CO), 1485w,
1446w, 1030 s ([BF4]-), 758 s, 697s. 1H NMR (CDCl3): 7.96 (t, 1H,
1
6H, para-CH3), 1.70–1.40 (m, 8H, COD-CH2). 19F{ H} NMR
1
(CDCl3): -154.2 (s, [BF4]-). 31P{ H} NMR (CDCl3): -6.6 (s,
IrPPh2CCPh). m/z (FAB) 891 ([M-BF4]+, 783 ([M-COD-BF4]+),
605 ([M-PPh2CCPh-BF4]+).
(Pyridine)(1,3-bis{2,4,6-trimethylphenyl}imidazol-2-ylidene)-
(cyclo-octa-1,5-diene)iridium tetrafluoroborate (7). The title com-
pound, an air-sensitive yellow solid, was isolated in a similar
manner to that described for 5 (0.21 g, 70%). Anal. Calc. for
C34H41BF4IrN3: C, 52.95, H, 5.36, N, 5.45. Found: C, 52.80, H,
5.39, N, 5.39. nmax/cm-1 2919w, 1485w, 1443 s, 1032vs ([BF4]-),
758 s, 699s. 1H NMR (CDCl3): 7.67 (m, 2H, ArH), 7.64 (m, 1H,
ArH), 7.11 (m, 2H, ArH), 6.95 (br s, 6H, ArH and NCHCHN),
3.56 (m, 2H, COD-CH), 3.13 (m, 2H, COD-CH), 2.34 (s, 6H,
para-CH3), 2.04 (s, 12H, ortho-CH3), 2.00–1.50 (m, 8H, COD-
3
3JHH = 7.6 Hz, PyH), 7.71 (d, 2H, JHH = 7.2 Hz, PyH), 7.42 (t,
3
2H, JHH = 6.8 Hz, PyH), 7.19 (s, 2H, NCHCHN), 6.93 (s, 4H,
1
ArH), 2.33 (s, 6H, para-CH3), 1.98 (s, 12H, ortho-CH3). 19F{ H}
NMR (CDCl3): -153.3 (s, [BF4]-). m/z (FAB) 632 ([M-BF4]+), 576
([M-2CO-BF4]+).
(Pyridine)(1,3-bis{2,6-diisopropylphenyl}imidazol-2-ylidene)-
(dicarbonyl)iridium tetrafluoroborate (12). The title compound,
an air-sensitive yellow powder, was isolated in a similar manner
to that described for 9 (0.35 g, 99%). All attempts to obtain
satisfactory elemental analysis data for 12 were unsuccessful due
to the air sensitivity. nmax/cm-1 2970w, 2068 s (CO), 2000 s (CO),
1
CH2). 19F{ H} NMR (CDCl3): -153.1 (s, [BF4]-). m/z (FAB) 684
([M-BF4]+), 605 ([M-Py-BF4]+).
(Pyridine)(1,3-bis{2,6-diisopropylphenyl}imidazol-2-ylidene)-
(cyclo-octa-1,5-diene)iridium tetrafluoroborate (8). The title com-
pound, an air-sensitive yellow solid, was isolated in a similar
manner to that described for 5 (0.19 g, 57%). Anal. Calc. for
C40H53BF4IrN3·0.5CH2Cl2: C, 54.17, H, 6.07, N, 4.68. Found: C,
54.01, H, 6.30, N, 4.33. nmax/cm-1 2964 s, 1444 s, 1032 s ([BF4]-),
752s. 1H NMR (CDCl3): 7.66 (m, 4H, ArH), 7.60 (m, 2H, ArH),
7.41 (m, 5H, ArH), 3.65 (m, 2H, COD-CH), 3.08 (m, 2H, COD-
CH), 2.02 (m, 2H, CH3CH), 1.91 (m, 2H, CH3CH), 1.40–1.00 (m,
1
1451 s, 1032 s ([BF4]-), 758 s, 695s. H NMR (CDCl3): 7.99 (m,
1H, ArH 7.63 (t, 2H, 3JHH = 7.9 Hz, ArH 7.52 (m, 4H, ArH 7.36
(4H, d, 3JHH = 7.9 Hz, ArH 2.72 (sep, 4H, 3JHH = 6.7 Hz, CH3CH),
1.23 (d, 12H, 3JHH = 7.0 Hz, CH3CH), 1.17 (d, 12H, 3JHH = 6.7 Hz,
1
CH3CH). 19F{ H} NMR (CDCl3): -153.1 (s, [BF4]-). m/z (FAB)
716 ([M-BF4]+), 637 ([M-py-BF4]+).
(1,3-Bis{2,4,6-trimethylphenyl}imidazol-2-ylidene)(cyclo-octa-
1,5-diene)chlorodifluoroiridium(III) (13). Complex 1 (41 mg,
0.064 mmol) was loaded into a pre-seasoned 4 mm O.D. (outside
diameter) FEP (perfluoroethylene/propylene copolymer) tube
connected to a T-union. XeF2 (14 mg, 0.083 mmol was loaded
into a 4 mm O.D. FEP tube connected to the perpendicular elbow
of the union, ensuring that mixing of the two solids could not
1
32H, CH3CH and COD-CH2). 19F{ H} NMR (CDCl3): -152.9
(s, [BF4]-). m/z (FAB) 768 ([M]+), 689 ([M-Py]+).
(Ethyldiphenylphosphine)(1,3-bis{2,4,6-trimethylphenyl}imida-
zol-2-ylidene)(dicarbonyl)iridium tetrafluoroborate (9). Carbon
monoxide was bubbled through a stirred solution of 5 (400 mg,
10786 | Dalton Trans., 2010, 39, 10781–10789
This journal is
The Royal Society of Chemistry 2010
©

View Article Online
occur. The reactor was re-connected to the line, and the connectors
passivated. Freshly distilled dichloromethane (ca. 1 cm3) was
condensed into both FEP tubes at -196 ◦C, and the solutions
cautiously warmed to ensure complete dissolution of the solids.
7.61–7.03 (m, 16H, ArH and NCHCHN), 2.65 (m, 2H, PCH2),
1
2.43–1.95 (m, 18H, CH3), 1.10–0.92 (m, 3H, PCH2CH3). 19F{ H}
NMR (CDCl3): -152.2 (s, [BF4]-) -328.6 (d, 2JPF = 36 Hz, IrF2, F-
trans-CO isomer), -521.8 (d, 2JPF = 20 Hz, IrF2, F-trans-F isomer).
◦
1
2
The solution of 1 was cooled to -196 C, and the XeF2 solution
31P{ H} NMR (CDCl3): -2.9 (t, JPF = 36 Hz, IrP2, F-trans-CO
isomer), -22.1 (t, 2JPF = 20 Hz, IrP2, F-trans-F isomer). m/z (FAB)
805 ([M-BF4]+), 785 ([M-HF-BF4]+), 777 ([M-CO-BF4]+), 767 ([M-
2F-BF4]+), 758 ([M-CO-HF-BF4]+).
added in a single aliquot. The solution was cautiously warmed to
◦
-80 C with agitation. Once reaction was deemed complete, the
FEP tube was heat sealed for NMR studies at -60 ◦C. 1H NMR
(CDCl3): 7.19 (s, 2H, NCHCHN), 6.89 (s, 4H, ArH), 5.95 (br s,
1H, COD-CH), 5.60 (br s, 1H, COD-CH), 5.10 (br s, 2H, COD-
Difluoro(phenylethynyldiphenylphosphine)(1,3-bis{2,4,6-trime-
1
CH), 2.50–1.85 (m, 26H, CH3 and COD-CH2). 19F{ H} NMR
thylphenyl}imidazol-2-ylidene)(dicarbonyl)iridium
tetrafluoro-
2
borate (18). The title compound, an air-sensitive pale yellow
powder, was isolated in a similar manner to that described for
13. NMR spectra were recorded at -60 ◦C. Anal. Calc. for
C43H39BF6IrN2O2P: C, 53.56, H, 4.08, N, 2.91. Found: C, 53.49,
H, 4.13, N, 2.93. nmax/cm-1 2168 s (CC), 2084 s (CO), 1994 s
(CO), 1479 s, 1438 s, 1052 s ([BF4]-) 853 s, 752 s, 685s. 1H NMR
(CDCl3): 7.75–7.20 (m, 19H, ArH), 7.18 (s, 2H, NCHCHN),
(CDCl3): -273.5 (d, JFF = 141 Hz, IrF {F-trans-olefin}), -382.5
(d, 2JFF = 141 Hz, IrF {F-trans-Cl}).
(1,3-Bis{2,6-diisopropylphenyl}imidazol-2-ylidene)(cyclo-octa-
1,5-diene)chlorodifluoroiridium(III) (14). The title compound was
generated in a similar manner to that described for 13. NMR
spectra were recorded at -60 ◦C. 1H NMR (CDCl3): 7.34 (t, 2H,
3JHH = 7.7 Hz, para-CH), 7.18 (d, 4H, 3JHH = 7.6 Hz, meta-CH),
5.89 (br s, 1H, COD-CH), 5.48 (br s, 1H, COD-CH), 4.95 (br s,
2H, COD-CH), 3.05 (sep, 2H, 3JHH = 7.1 Hz, CH3CH), 2.87 (sep,
2H, 3JHH = 6.8 Hz, CH3CH), 2.23–1.50 (m, 8H, COD-CH2), 1.03
1
2.38–1.89 (m, 18H, CH3). 19F{ H} NMR (CDCl3): -152.7 (s,
2
[BF4]-), -335.0 (d, JFP = 42 Hz, IrF2 {F-trans-CO}); -517.3 (d,
1
2JFP = 25 Hz, IrF2 {F-trans-F}). 31P{ H} NMR (CD2Cl2): -42.9
2
2
(t, JPF = 25 Hz, IrP2 {F-trans-F}), -36.3 (t, JPF = 42 Hz, IrP2
{F-trans-CO}). m/z (FAB) 877 ([M-BF4]+), 857 ([M-HF-BF4]+),
839 ([M-2F-BF4]+), 829 ([M-HF-CO-BF4]+).
3
3
(d, 12H, JHH = 6.7 Hz, CH3CH), 1.00 (d, 12H, JHH = 7.1 Hz,
CH3CH).19F{ H} NMR (CDCl3): -270.3 (d, JFF = 147 Hz, IrF
1
2
{F-trans-olefin}), -386.9 (d, 2JFF = 147 Hz, IrF {F-trans-Cl}).
Difluoro(pyridine)(1,3-bis{2,4,6-trimethylphenyl}imidazol-2-
ylidene)(dicarbonyl)iridium tetrafluoroborate (19). The title com-
pound, an air-sensitive pale yellow powder, was isolated in a similar
manner to that described for 13. NMR spectra were recorded at
(1,3-Bis{2,4,6-trimethylphenyl}imidazol-2-ylidene)(dicarbonyl)-
chlorodifluoroiridium(III) (15). The title compound was prepared
in a similar manner to that described for 13. Once reaction
was deemed complete, the FEP tube was either heat sealed
for NMR studies, or the solvent removed in vacuo, affording
[IrF2Cl(IMes)(CO)2] (15) as an air-sensitive pale yellow pow-
der. NMR spectra were recorded at -60 ◦C. Anal. Calc. for
C23H24ClF2IrN2O2: C, 44.10, H, 3.86, N, 4.47. Found: C, 44.11,
H, 3.74, N, 4.41. nmax/cm-1 2050 s (CO), 1969 s (CO), 1485 s 850 s,
◦
-60 C. Anal. Calc. for C28H29BF6IrN3O2: C, 44.02, H, 3.86, N,
5.55. Found: C, 44.07, H, 3.91, N, 5.43. nmax/cm-1 2924w, 2062 s
(CO), 1483 s, 1454 s, 1030 s ([BF4]-), 761 s, 697s. 1H NMR (CDCl3):
8.10–7.25 (m, 9H, ArH), 7.20 (s, 2H, NCHCHN), 2.36–1.97 (m,
1
18H, CH3). 19F{ H} NMR (CDCl3) -151.9 (s, [BF4]-), -318.9 (s,
IrF2 {F-trans-CO}), -455.1 (s, IrF2 {F-trans-F}). m/z (FAB) 650
1
705s. H NMR (CDCl3): 7.20 (s, 2H, NCHCHN), 6.95 (s, 4H,
([M-HF-BF4]+), 632 ([M-2F-BF4]+), 622 ([M-HF-CO-BF4]+).
1
ArH), 2.28 (s, 6H, para-CH3), 2.14 (s, 12H, ortho-CH3). 19F{ H}
2
NMR (CDCl3): -311.3 (d, JFF = 121 Hz, IrF {F-trans-CO}),
Difluoro(pyridine)(1,3-bis{2,6-diisopropylphenyl}imidazol-2-
ylidene)(dicarbonyl)iridium tetrafluoroborate (20). The title com-
pound, an air-sensitive pale yellow powder, was isolated in a similar
manner to that described for 13. NMR spectra were recorded at
-397.4 (d, 2JFF = 121 Hz, IrF {F-trans-Cl}).
(1,3-Bis{2,6-diisopropylphenyl}imidazol-2-ylidene)(dicarbonyl)-
chlorodifluoroiridium(III) (16). The title compound, an air-
sensitive pale yellow powder, was isolated in a similar manner to
that described for 13. NMR spectra were recorded at -60 ◦C. Anal.
Calc. for C29H36ClF2IrN2O2: C, 49.02, H, 5.11, N, 3.94. Found: C,
48.96, H, 5.00, N, 3.91. nmax/cm-1 2964 s, 2146 s (CO), 2056 s (CO),
◦
-60 C. Anal. Calc. for C34H41BF6IrN3O2: C, 48.54, H, 4.92, N,
5.00. Found: C, 48.41, H, 4.79, N, 4.97. nmax/cm-1 2969 s, 2056 s
(CO), 1978 s (CO), 1452 s, 1051 s ([BF4]-), 758 s, 697s. 1H NMR
(CDCl3): 8.12 (m, 2H, ArH), 7.91 (m, 2H, ArH), 7.50–7.03 (m,
7H, ArH), 7.19 (s, 2H, NCHCHN), 2.48 (m, 2H, CH3CH), 2.29
1
3
1460 s, 800 s, 755 s, 708s. H NMR (CDCl3): 7.46 (t, 2H, JHH
=
1
(m, 2H, CH3CH), 1.32–1.09 (m, 24H, CH3CH). 19F{ H} NMR
3
7.6 Hz, para-CH), 7.25 (d, 4H, JHH = 7.6 Hz, meta-CH), 7.03
(CDCl3) -151.3 (s, [BF4]-), -303.4 (s, IrF2 {F-trans-CO}), -458.1
(s, IrF2 {F-trans-F}).
(s, 2H, NCHCHN), 2.75 (m, 4H, CH3CH), 1.27 (d, 12H, 3JHH
=
6.8 Hz, CH3CH), 1.05 (d, 12H, 3JHH = 6.8 Hz, CH3CH). 19F{ H}
1
2
NMR (CDCl3): -307.9 (d, JFF = 122 Hz, IrF {F-trans-CO}),
Difluoro(pyridine)(1,3-bis{2,4,6-trimethylphenyl}imidazol-2-
ylidene)(cyclo-octa-1,5-diene)iridium tetrafluoroborate (21). The
title compound was isolated in a similar manner to that described
-400.3 (d, 2JFF = 123 Hz, IrF {F-trans-Cl}).
Difluoro(ethyldiphenylphosphine)(1,3-bis{2,4,6-trimethylphe-
nyl}imidazol-2-ylidene)(dicarbonyl)iridium tetrafluoroborate (17).
The title compound, an air-sensitive pale yellow powder, was
isolated in a similar manner to that described for 13. Repeated
attempts to obtain satisfactory elemental analysis data for 17 were
unsuccessful due to the air sensitivity. NMR spectra were recorded
at -60 ◦C. nmax/cm-1 2924w, 2090 s (CO), 2067 s (CO), 1986br
(CO), 1483 s, 1435 s, 1051 s ([BF4]-), 741 s, 690s. 1H NMR (CDCl3):
◦
for 13. NMR spectra were recorded at -60 C. nmax/cm-1 2919w,
1
1483 s, 14492, 1029vs ([BF4]-), 761 s, 699s. H NMR (CDCl3):
8.50 (m, 2H, ArH), 8.02 (m, 2H, ArH), 7.44 (m, 1H, ArH), 6.88
(m, 6H, ArH and NCHCHN), 5.88 (br s, 2H, COD-CH), 4.94
(br s, 2H, COD-CH), 2.40–1.80 (m, 26H, CH3 and COD-CH2).
1
19F{ H} NMR (CDCl3) -152.3 (s, [BF4]-), -425.2 (s, IrF2). m/z
(FAB) 722 ([M]+).
This journal is
The Royal Society of Chemistry 2010
Dalton Trans., 2010, 39, 10781–10789 | 10787
©

View Article Online
Table 4 Crystallographic and data processing parametersa for (5), (6), (8), (9) and (11)
Complex
(5)
(6)
(8)
(9)
(11)
Formula
M
C43H47BF4IrN2P
901.81
150(2)
Orthorhombic
P212121
11.9712(16)
15.996(2)
19.958(3)
90
90
90
3821.7(9)
4
1.567
3.589
1808
C49H51BF4IrN2P
977.90
150(2)
Triclinic
P1
10.3704(17)
13.371(2)
15.841(3)
87.867(3)
75.097(2)
89.756(3)
2121.1(6)
2
C83H104B2Cl6F8Ir2N6
1956.44
150(2)
C37.5H39.5BCl1.5F4IrN2O2P
913.37
150(2)
C28H29BF4IrN3O2
718.55
150(2)
Orthorhombic
P212121
10.8033(18)
15.976(3)
16.117(3)
90
90
90
2781.7(8)
4
1.716
4.857
1408
Temperature/K
Crystal system
Space group
Triclinic
Triclinic
¯
¯
P1
P1
˚
a/A
11.0104(17)
19.823(3)
21.835(3)
66.828(2)
78.610(2)
78.803(2)
4258.9(11)
2
8.472(13)
15.20(2)
˚
b/A
˚
c/A
16.07(2)
81.60(2)
76.57(2)
76.53(2)
1948(5)
2
1.557
3.624
a (◦)
b (◦)
g (◦)
3
˚
U/A
Z
Dc/g cm-3
m(Mo-Ka)/mm-1
F(000)
1.531
3.240
984
1.526
3.373
1964
906
Crystal size/mm
Theta range (◦)
Index Ranges
0.08 ¥ 0.15 ¥ 0.17
1.63 to 27.00
-15 £ h £ 15
-20 £ k £ 20
-25 £ l £ 25
32446
0.30 ¥ 0.24 ¥ 0.11
1.52 to 26.00
-12 £ h £ 12
-16 £ k £ 16
-19 £ l £ 19
16617
0.29 ¥ 0.19 ¥ 0.18
1.78 to 27.00
-13 £ h £ 14
-25 £ k £ 25
-27 £ l £ 27
35820
0.36 ¥ 0.27 ¥ 0.13
1.31 to 27.00
-10 £ h £ 10
-19 £ k £ 18
-19 £ l £ 20
16473
0.37 ¥ 0.11 ¥ 0.09
1.79 to 27.00
-13 £ h £ 13
-20 £ k £ 20
-20 £ l £ 19
23340
Reflections collected
Independent reflections
Rint
Max. and min. transmission
Restraints/parameters
Final R indices (I > 2s(I))
8344
0.0489
8227
0.0244
18210
0.0261
8374
0.0713
6030
0.0433
0.7115 and 0.8621 0.928 and 0.651
0/476
R1 = 0.0310
wR2 = 0.0536
R1 = 0.0370
wR2 = 0.0551
0.913
0.861 and 0.620
0/989
R1 = 0.0355,
wR2 = 0.0932
R1 = 0.0447,
wR2 = 0.0970
1.028
0.928 and 0.467
0/440
R1 = 0.0455
wR2 = 0.1235
R1 = 0.0504
wR2 = 0.1406
1.175
0.862 and 0.503
0/385
R1 = 0.0258
wR2 = 0.0528
R1 = 0.0295
wR2 = 0.0535
0.976
0/528
R1 = 0.0270,
wR2 = 0.0643
R1 = 0.0296,
wR2 = 0.0654
1.008
All data
Goodness of fit of F2 (all data)
Largest diff. peak and hole/e A
-3
˚
1.208 and -0.568
1.369 and -0.937
2.467 and -0.945
2.844 and -2.785
1.846 and -1.027
ꢀ
ꢀ
ꢀ
ꢀ
a
2
Data in common: graphite-monochromated Mo-Ka radiation, l = 0.71073 A; R1 = ꢀFo| - |Fcꢀ/ |Fo|, wR2 = [ w(Fo - Fc2)2/ w(Fo2)2]1/2, w-1
=
˚
ꢀ
[s (Fo)2 + (aP)2], P = [max(Fo2,0) + 2(Fc2)]/3, where a is a constant adjusted by the program; goodness of fit = [ (Fo - Fc2)2/(n - p)]1/2 where n is the
number of reflections and p the number of parameters.
2
2
Crystallography
to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK, (fax: +44
1223 336033 or e-mail: deposit@ccdc.cam.ac.uk).
Single crystals of 5, 6 and 8 were grown by careful layering
of DCM–hexane solutions evaporation, crystals of 9 by slow
evaporation of a saturated chloroform solution and crystals of
11 by slow vapour diffusion of a hexane into a saturated DCM
solution. Data for each of the crystals were collected on a Bruker
APEX 2000 CCD diffractometer using graphite-monochromated
Acknowledgements
We thank the EPSRC for financial support.
˚
Mo-Ka radiation (l = 0.71073 A). Details of data collection,
References
refinement and crystal data are listed in Table 4. Data for the
cyclometallated IMes complex, [IrF(IMes)(CO)2(PPh2Et)]+[BF4]-,
were collected similarly, but were not stable to full anisotropic
refinement. The data were corrected for Lorentz and polarization
effects and empirical corrections applied. The structures were
solved by direct methods. The structure refinement on F2 employed
SHELXTL VERSION 6.10.33 Hydrogen atoms were included in
1 N. D. Ball, J. W. Kampf and M. S. Sanford, Dalton Trans., 2010, 39,
632.
2 A. Yahav, I. Goldberg and A. Vigalok, Inorg. Chem., 2005, 44, 1547.
3 V. V. Grushin and W. J. Marshall, J. Am. Chem. Soc., 2009, 131, 918.
4 M. Gorol, N. C. Mosch-Zanetti, H. W. Roesky, M. Noltemeyer and
H.-G. Schmidt, Eur. J. Inorg. Chem., 2004, 2678.
5 T. Furuya and T. Ritter, J. Am. Chem. Soc., 2008, 130, 10060.
6 C. J. Bourgeois, S. A. Garratt, R. P. Hughes, R. B. Larichev, J. M. Smith,
A. J. Ward, S. Willemsen, D. Zhang, A. G. DiPasquale, L. N. Zakharov
and A. L. Rheingold, Organometallics, 2006, 25, 3474.
7 J. Vela, J. M. Smith, Y. Yu, N. A. Ketterer, C. J. Flaschenriem, R. J.
Lachicotte and P. L. Holland, J. Am. Chem. Soc., 2005, 127, 7857.
8 J. Fawcett, D. A. J. Harding and E. G. Hope, Dalton Trans., 2010, 39,
5827.
9 F. E. Hahn and M. C. Jahnke, Angew. Chem., Int. Ed., 2008, 47, 3122.
10 D. S. Laitar, T. G. Mu¨ller, T. H. Gray and J. P. Sadighi, Organometallics,
2005, 24, 4503.
11 S. L. Chatwin, M. G. Davidson, C. Doherty, S. M. Donald, R. F. R.
Jazzar, S. A. Macgregor, G. J. McIntyre, M. F. Mahon and M. K.
Whittlesey, Organometallics, 2006, 25, 99.
˚
calculated positions (C–H = 0.93–0.98 A) riding on the bonded
atom with isotropic displacement parameters set to 1.5 Ueq(C) for
methyl H atoms and 1.2 Ueq(C) for all other H atoms. All non-
H atoms were refined with anisotropic displacement parameters.
Disordered solvent was omitted using the SQUEEZE option in
Platon34 for [9 (0.5 CHCl3)].
Crystallographic data for the structures in this paper have
been deposited with the Cambridge Crystallographic Data Centre
as supplementary information CCDC numbers 723140–723144.‡
Copies of the data can be obtained, free of charge, on application
10788 | Dalton Trans., 2010, 39, 10781–10789
This journal is
The Royal Society of Chemistry 2010
©

View Article Online
12 S. P. Reade, D. Nama, M. F. Mahon, P. S. Pregosin and M. K.
Whittlesey, Organometallics, 2007, 26, 3484.
13 T. Schaub, M. Backes and U. Radius, J. Am. Chem. Soc., 2006, 128,
15964.
22 A. C. Hillier, H. M. Lee, E. D. Stevens and S. P. Nolan, Organometallics,
2001, 20, 4246.
23 W. A. Herrmann, M. Elison, J. Fischer, C. Kocher and G. R. Artus,
Angew. Chem., Int. Ed. Engl., 1995, 34, 2371.
14 T. Schaub, P. Fischer, A. Steffen, T. Braun, U. Radius and A. Mix,
J. Am. Chem. Soc., 2008, 130, 9304.
15 J. Fawcett, D. A. J. Harding, E. G. Hope and G. A. Solan, Dalton Trans.,
2009, 6861.
24 A. J. Davenport, D. L. Davies, J. Fawcett and D. R. Russell, Dalton
Trans., 2004, 1481.
25 A. C. Chen, L. Ren, A. Decken and C. M. Crudden, Organometallics,
2000, 19, 3459.
16 K. S. Coleman, J. Fawcett, J. H. Holloway, E. G. Hope and D. R.
Russell, J. Chem. Soc., Dalton Trans., 1997, 3557.
26 G. Altenhoff, R. Goddard, C. W. Lehmann and F. Glorius, J. Am.
Chem. Soc., 2004, 126, 15195.
27 R. W. Cockman, E. A. V. Ebsworth and J. H. Holloway, J. Am. Chem.
Soc., 1987, 109, 2194.
28 S. A. Brewer, J. H. Holloway, E. G. Hope and P. G. Watson, J. Chem.
Soc., Chem. Commun., 1992, 1577.
29 M. A. Cairns, K. R. Dixon and J. J. McFarland, J. Chem. Soc., Dalton
Trans., 1975, 1159.
30 T. M. Trnka, J. P. Morgan, M. S. Sanford, T. E. Wilhelm, M. Scholl,
T.-L. Choi, S. Ding, M. W. Day and R. H. Grubbs, J. Am. Chem. Soc.,
2003, 125, 2546.
31 S. A. Brewer, K. S. Coleman, J. Fawcett, J. H. Holloway, E. G. Hope,
D. R. Russell and P. G. Watson, J. Chem. Soc., Dalton Trans., 1995,
1073.
17 R. W. Cockman, E. A. V. Ebsworth, J. H. Holloway, H. Murdoch, N.
Robertson and P. G. Watson, ACS Symposium Series 555: Inorganic
Fluorine Chemistry, ed. J. S. Thrasher and S. H. Strauss, pp. 326.
18 See for example, and refs therein: (a) R. A. Kelly, H. Clavier, S. Giudice,
N. M. Scott, E. D. Stevens, J. Bordner, I. Samardjiev, C. D. Hoff, L.
Cavallo and S. P. Nolan, Organometallics, 2008, 27, 202; (b) G. D.
Frey, C. F. Rentzsch, D. Von Preysing, F. Scherg, M. Mu¨hlhofer, E.
Herdtweck and W. A. Herrmann, J. Organomet. Chem., 2006, 691,
5725; (c) S. Luetha¨ußer, D. Schwarz and H. Plenio, Chem.–Eur. J., 2007,
13, 7195; (d) I. Kownacki, M. Jukicki, K. Szubert and B. Marciniec,
J. Organomet. Chem., 2008, 693, 321.
19 L. D. Va´zquez-Serrano, B. T. Owens and J. M. Buriak, Chem. Commun.,
2002, 2518.
20 A. R. Chianese, A. Kovacevic, B. M. Zeglis, J. W. Faller and R. H.
Crabtree, Organometallics, 2004, 23, 2461.
21 K. Denk, P. Sirsch and W. A. Herrmann, J. Organomet. Chem., 2002,
649, 219.
32 W. L. F. Armarego and D. D. Perrin, Purification of Laboratory
Chemicals, Butterworth Heinemann, 4th edn, 1996.
33 G. M. Sheldrick, SHELXTL Version 6.10, Bruker AXS Inc., Madison,
Wisconsin, USA, 2000.
34 A. L. Spek, Acta Cryst. Sect. A, 1990, 46, C–34.
This journal is
The Royal Society of Chemistry 2010
Dalton Trans., 2010, 39, 10781–10789 | 10789
©