Mononuclear rhodium and iridium compounds with pyridyl-pyrazole ligands

Article abstract of DOI:10.1016/j.ica.2004.11.005

Neutral [MCl(L₂)(Hpzpy)], [M(L₂)(pzpy)] and cationic [M(L₂)(Hpzpy)]CF₃SO₃ rhodium(I) or iridium(I) complexes [M = Rh or Ir; L₂ = diolefin or (CO)₂; pzpy = 3-(2-pyridyl)pyrazolate

Full text of DOI:10.1016/j.ica.2004.11.005

Inorganica Chimica Acta 358 (2005) 1635–1644
www.elsevier.com/locate/ica
Mononuclear rhodium and iridium compounds with
pyridyl-pyrazole ligands
a
a
a,
a
Ana P. Martınez , Marıa Jose Fabra , Marıa P. Garcıa *, Fernando J. Lahoz ,
´
´
´
´
´
a
Luis A. Oro , Simon J. Teat
b
a
´ ´ ´
Departamento de Quımica Inorganica, Instituto de Ciencia de Materiales de Aragon, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, Spain
b
SERC, Daresbury Lab, CLCR, Warrington, Cheshire WA4 4AD, England, UK
Received 5 October 2004; accepted 10 November 2004
Available online 21 December 2004
Dedicated to Professor F. Gordon A. Stone on the occassion of his 80th birthday
Abstract
Neutral [MCl(L2)(Hpzpy)], [M(L2)(pzpy)] and cationic [M(L2)(Hpzpy)]CF3SO3 rhodium(I) or iridium(I) complexes [M = Rh or Ir;
L2 = diolefin or (CO)2; pzpy = 3-(2-pyridyl)pyrazolate] have been prepared; the pzpy and Hpzpy ligands coordinate to the metal as
bidentate chelate groups through one pyrazole nitrogen and the pyridine nitrogen atom. The reactivity of these complexes towards
oxidative addition reactions of halogens, methyl iodide or triflic acid and towards displacement reactions has been studied. The neutral
and cationic iridium(I) complexes are modest catalysts for the hydrosilylation of phenylacetylene with triethylsilane at 60 ꢀC. The com-
plexes have been characterised by analytical and spectroscopic data; their configuration has been confirmed by COSY and NOESY
experiments and the molecular structure of [Rh(COD)(Mepzpy)(PPh3)]CF3SO3 has been established by an X-ray diffraction study.
ꢁ 2004 Elsevier B.V. All rights reserved.
Keywords: Rhodium; Iridium; Pyridyl-pyrazole ligand; Oxidative addition; X-ray crystallography
1. Introduction
such ligands give rise to significantly different elec-
tronic properties [4,5]. The strong r-donor properties
of the pyrazole group, together with the p-accepting
ability of the pyridyl ring, enhance the stability of
the five-membered ring metal chelate. Among this type
of ligands, the 3-(2-pyridyl)pyrazole provides a great
potential to isolate mono- or polynuclear complexes.
With this ligand, transition metal complexes as well
as complexes containing principal group metals have
been described [6–13].
Pyrazoles are known as both monodentate and exo-
bidentate ligands and their nitrogen atoms coordinate
to the metal centre as both anionic or neutral groups.
Pyrazolate-bridged binuclear and polynuclear transition
metal complexes have attracted special interest for many
years [1–3].
An interesting situation arises when a five-mem-
bered heterocycle such as pyrazole and a six-mem-
bered heterocycle such as pyridine are directly linked
in a single ligand system. In fact, the complexes of
N
N
N
H
*
Corresponding author. Tel.: +34 976 761149; fax: +34 976 761187.
´
E-mail address: pilarg@unizar.es (M.P. Garcıa).
3-(2-pyridyl)pyrazole (Hpzpy)
0020-1693/$ - see front matter ꢁ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2004.11.005

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1636
One of our research interests consists of the study of
the N–H signals appear at d 15.2 (1), 15.9 (2) and 15.4
(3) ppm, downfield relative to the free ligand (d 12.0
ppm). Most of the signals of the aromatic protons of
the Hpzpy ligand are also shifted downfield with respect
to the free ligand albeit the observed displacement is rel-
atively small. However, the signal due to H2 proton,
ortho to the pyridinic nitrogen (see Section 3), is shifted
upfield and with larger displacement [Dd 1.0, (1), 1.2 (2)
and 0.7 (3)], showing that this proton increases its
shielding when the ligand coordinates to the metals. This
fact is probably due to the anisotropic effect caused by
the olefinic carbon–carbon double bond [18], very close
to the position of H2, and it has been observed in all
complexes described in this paper. Each diolefin, COD
or TFB, gives only a broad signal for the four @CH pro-
tons (from room temperature to ꢀ80 ꢀC) at d 4.7 (1), 4.5
(2) or 4.8 (3), which means that one or more dynamic
processes make equivalent the four olefinic protons.
The same behaviour has been observed for the four ole-
finic carbons. For complexes 1 and 3 signals in the
rhodium and iridium complexes, which are well known
to show good performance in various catalytic reac-
tions. Attention has been put in polynucleating ligands
in order to synthesize homo or hetero polynuclear com-
plexes [14–17], that could bring synergetic effects in their
potential catalytic activity.
As a first step towards the synthesis of polynuclear
species, in this paper, we wish to report the preparation
and characterization of a new series of neutral and cat-
ionic mononuclear rhodium or iridium complexes with
the 3-(2-pyridyl)pyrazole ligand. Their reactivity to-
wards oxidative addition, displacement or hydrosilyla-
tion reactions is described. In these compounds the
polydentate ligand coordinates to the metals through
the pyridine nitrogen and one of the pyrazole or pyraz-
olate nitrogens.
2. Results and discussion
1
13C{1H} NMR spectra were assigned through H-13C
The coordination of the 3-(2-pyridyl)pyrazole ligand,
acting as chelate to Rh or Ir, can be achieved from dif-
ferent starting products. The reaction of this ligand with
the chloro-bridge rhodium or iridium diolefin dimers,
[{M(l-Cl)(diolefin)}2], produces the cleavage of the
chloro bridges and the formation of the mononuclear,
pentacoordinated [MCl(Hpzpy)(diolefin)] [M = Rh,
diolefin = 1,5-cyclooctadiene, COD, (1) or tetra-
fluorobenzobarrelene, TFB, (2); M = Ir, diole-
fin = COD, (3)] complexes in high yield (Fig. 1). These
compounds were characterised on the basis of IR and
multinuclear NMR spectroscopy, microanalysis and
mass spectrometry.
correlation experiments. Complex 2 was not soluble en-
ough to run its 13C NMR spectrum. The signals of the
carbon atoms of the ligand Hpzpy in complexes 1 and
3 appear downfield respect to the free ligand with the
exception of C2 that moves upfield upon coordination.
Compounds 1 and 3 only show one signal, at d 83.8
2
(d, JRh–C = 12.4 Hz, 1) and 70.3 (s, 3), for the four
@CH groups, either at room or low temperature. This
fluxional behaviour has only been observed in the penta-
coordinated complexes prepared with this ligand, so the
equilibrium in solution may be associated to the penta-
coordination, like Berryꢀs pseudorotation.
The reaction of the Hpzpy ligand with the solvated
[M(diolefin)(Me2CO)x]+ intermediates, prepared by the
reaction of the chloro-bridged Rh or Ir dimers with sil-
ver salts and filtration of the silver chloride formed,
causes the displacement of the solvent giving square-
planar cationic mononuclear complexes [M(Hpzpy)-
(COD)]+, crystallized with triflate as counterion,
[M = Rh (4) or Ir (5)]. These products are solids of
bright colours (yellow and red, respectively) stable to
the air. In their IR spectra the absorption due to the trif-
lato group, at around 1300 cmꢀ1, can be observed. Their
conductivity measures show the complexes to be 1:1
electrolytes in acetone. The proton NMR spectra of
these complexes consist of broad signals for the acidic
protons of the pyrazole ligands at d 13.6 (4) and 14.1
(5). The resonances of the remaining six protons of the
ligand are observed between d 6.7 and 8.1 all shifted
downfield with the commented exception of H2 that ap-
pears upfield with respect to the free ligand. At higher
fields the signals of the COD ligand are localized: the
olefinic protons at d 5.1 and 4.3 ppm for (4) and 5.0
and 4.0 (5) ppm (2 protons each) and the CH2 hydro-
gens give two signals between d 1.9 and 2.5 ppm. The
The coordination of the chlorine atom to the metal
can be inferred from the IR absorption bands at 297
1
(1), 275 (2) and 235 (3) cmꢀ1. In the H NMR spectra
+
HN
N
HN
Cl
N
M
M
N
N
1-3
4, 5
Me
N
N
N
N
M
M
N
N
11, 12
6, 7
M = Rh or Ir; diolefin = COD or TFB
Fig. 1. Structures of various rhodium or iridium complexes in this
study.

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1637
13C{1H} NMR spectra show the signals due to the pyr-
azole ligand together with those of the COD group;
however there is not signal detected for the triflate an-
ion, probably due to the limited solubility of these com-
pounds and to the difficulty of observing quaternary
carbons with high multiplicity.
symmetry plane in the molecule that should be coinci-
dent with the coordination plane of the pzpy ligand,
and corroborate the configuration of complex 8 as the
trans isomer.
The reaction with chlorine of complexes 1–7 gives sol-
ids of low solubility and their NMR spectra indicate
that mixtures of products are present. However the com-
plex cis-[IrCl2(pzpy)(COD)] (9) has been obtained by
reaction of complex 7 with [AuCl(tht)] (tht = tetrahy-
drothiophene). The reaction was planned to prepare a
dinuclear Ir–Au complex by coordination of the gold
to the deprotonated nitrogen of the pzpy ligand. The
dinuclear compound is probably formed but quickly
evolves to give gold metal and the yellow compound 9.
The reaction is not a conventional oxidative addition
reaction but a redox reaction involving the two metals.
The iridium is oxidised from Ir(I) to Ir(III) and the gold
is reduced from Au(I) to Au(0). The characterisation
and the stereochemistry of complex 9 have been as-
signed by combining information from the 1H and
13C{1H} NMR spectra and from NOE experiments.
All data (see Section 3) are in agreement with the cis dis-
position of the chlorine atoms, being one of them trans
to the N-pyrazole and the other trans to a C@C double
bond.
Reactions with trifluoromethylsulfonic acid. The
reactions of HOtf with CH2Cl2 solutions of complexes
1, 4 or 5 gave mixtures of unidentified products. The
reaction with complex 3 led to the oxidative addition
of the reagent and to the preparation of a hydride Ir(III)
complex of stoichiometry [Ir(H)Cl(Hpzpy)(COD)]Otf.
However the product was a mixture of three isomers
and, even doing the reaction at low temperature, none
of them could be isolated. With complexes 6 and 7 the
triflic acid produces the protonation of the pzpy ligand
giving complexes 4 and 5, respectively.
Neutral square-planar mononuclear complexes
[M(pzpy)(COD)] [M = Rh (6) or Ir (7)], in which the
pyrazole has lost its acidic proton, have also been
prepared by reaction of the ligand with the methoxy-
bridged rhodium or iridium dimers [{M(l-OMe)(diole-
fin)}2]. The presence of a nitrogen atom uncoordinated
with a free electron pair makes these monomers poten-
tially useful to prepare complexes of higher nuclearity.
The 1H NMR spectra were assigned on the basis of
1H and 1H-13C correlation experiments. The absence
of the acidic proton can be deduced from the proton
NMR spectra: no signals above d 8 ppm were detected.
The integrals of the pzpy and COD signals are in 1:1
proportion. The olefinic protons of the COD give two
signals of two protons each, at d 5.0 and 4.1 ppm (6)
and d 4.9 and 3.7 ppm (7). The 13C{1H} NMR spectra
show the signals of the 8 carbon atoms of the ligand
as well as the resonances of the carbons of the COD
(two for the olefinic protons, doublets with
3JRh–C = 12.1 y 11.1 Hz for compound 6, and two for
the CH2 protons) (see Section 3).
2.1. Oxidative addition reactions
Due to the great importance of the oxidative addition
processes and the possibility of oxidation of complexes
of Rh(I) or Ir(I) to Rh(III) and Ir(III) we have carried
out a study of this type of reactions on the prepared
complexes. An important factor to force the complexes
to experiment this type of reactions is that the metal
maintains a relatively high electron density. In our case,
the metal is bonded to a diolefin and to the pyridinyl-
pyrazole ligand. The bond of the diolefin to the metal
has an important p back component but the N of the
heterocycles has different behaviour according to the
size of the ring: the pyridine (6 member ring) is p-accep-
tor while the pyrazole (5 member ring) is better p-donor.
We have studied the reactions of the monomers with the
following oxidative addition reagents: chlorine, iodine,
triflic acid (HOtf), methyl iodide, and methyl triflate
(MeOtf).
Reactions with methyl iodide. Rhodium complexes
1, 4 or 6 did not give pure compounds under reaction
with MeI. With complex 1 only a slow Cl/I exchange
is detected. Complex 4 does not react with MeI and
complex 6 gives mixtures of products. Iridium com-
pounds 3, 5 and 7 react with MeI but while the white
reaction products of 3 and 5 where not completely
identified, 7 reacted immediately giving an octahedral
Ir(III) complex of stoichiometry [Ir(Me)I(pzpy)(COD)]
(10). The analytical and mass spectroscopic data are
1
in agreement with the proposed formulation. The H
Reactions with halogens. The reactivity of complexes
1–7 with iodine has been checked. All of them react but
only for complex 7 the isolation and characterization of
the final product, as trans-[IrI2(pzpy)(COD)] (8), has
and 13C{1H} NMR spectra show the lost of the sym-
metry plane of the molecule and NOE experiments
show that a trans addition has taken place which sug-
gest a SN2 mechanism for the oxidative addition
reaction.
1
been possible. The H NMR spectrum gives two multi-
plets for the @CH protons at d 6.2 and 5.7. The
13C{1H} NMR spectrum shows two signals for the
@CH at d 87.6 and 85.9, and two for the CH2 at d
32.4 and 32.3. These values indicate the presence of a
Trying to elucidate the mechanism of these reactions
we did the reactions of complexes 1–7 with methyl tri-
flate. With this reagent, the weakest oxidant used, only
the neutral square-planar complexes reacted but the

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1638
reactions do not produce the expected oxidation prod-
ucts. Instead, N-methylation of the pyrazolate ligand
takes place giving [M(Mepzpy)(COD)]Otf (M = Rh,
11, or Ir, 12)] cationic products. N-alkylation is one of
the most important and most studied reactions of pyraz-
oles. Can be carried out using alkyl halides (usually iod-
ides and bromides), diazomethane or alkyl salts [19].
Complex 12 is air, moisture and temperature sensitive
in solution or in solid state. The analytical data are in
agreement with the proposed formulation. Their con-
ductivity measures show the complexes to be 1:1 electro-
lytes in acetone and in CH2Cl2. The mass spectra
(FAB+) show the peaks for the species [M(Mepzpy)-
(COD)]. These data support its formulation as ionic spe-
cies with the Otf group out of the metal coordination
1
sphere. The H NMR spectra of 11 and 12 show only
one signal for the four @CH protons (at d 4.7, 11, and
4.5, 12); the methyl signals are at d 3.8 and 3.9, respec-
tively. In the 13C{1H} NMR spectrum of 12 the signal
of the methyl group appears at d 22.3.
Fig. 2. Molecular structure of complex 13. Hydrogens have been
omitted for clarity.
Complexes 11 and 12 react with PPh3 or P(OMe)3
giving pentacoordinated cationic species [M(Mepzpy)-
(COD)L]Otf [M = Rh, L = PPh3, 13, P(OMe)3, 14;
M = Ir, L = PPh3, 15, P(OMe)3, 16] with the phospho-
rous ligand joined to the Rh or Ir atoms. Both Rh(I)
complexes show thermal and air stability while the
Ir(I) compounds have to be kept under argon atmo-
sphere. Their corresponding analytical and spectro-
scopic data are shown in Section 3. They are 1:1
electrolytes in acetone solutions and, in CDCl3, the pen-
tacoordination around the metal atoms is maintained as
it can be observed in the NMR spectra.
Table 1
˚
Selected bond distances (A) and angles (ꢀ) for complex 13
Rh(1)–P(1)
2.3147(6)
2.1726(19)
2.313(2)
N(1)–N(2)
N(1)–C(1)
N(1)–C(9)
N(2)–C(7)
N(3)–C(2)
N(3)–C(6)
C(10)–C(11)
C(14)–C(15)
1.348(3)
1.439(3)
1.353(3)
1.344(3)
1.344(3)
1.345(3)
1.421(4)
1.374(4)
Rh(1)–N(2)
Rh(1)–N(3)
Rh(1)–M(1)a
Rh(1)–C(10)
Rh(1)–C(11)
Rh(1)–M(2)a
Rh(1)–C(14)
Rh(1)–C(15)
1.9834(18)
2.125(2)
2.088(2)
2.1071(18)
2.204(2)
2.228(2)
A single-crystal diffraction study of complex 13 was
carried out to get an insight into its geometrical molec-
ular parameters. A perspective view of the cationic metal
complex, together with the atomic numbering scheme, is
illustrated in Fig. 2; selected bond lengths and angles are
listed in Table 1. The rhodium atom exhibits a saturated
penta-coordinated environment, with bonds to the two
nitrogens of the pyridylpyrazole and to the two olefinic
moieties.
The metal coordination sphere is well described in
terms of a slightly distorted trigonal-bipyramidal struc-
ture. The phosphine ligand and the C(14)–C(15) double
bond of the cyclo-octadiene group occupy the axial posi-
tions; the three remaining coordinated moieties config-
ure the equatorial plane (two nitrogens and the second
olefinic double bond C(10)–(17)). The major terms of
distortion come from the geometrical restrains intro-
duced by the two quelating ligands: the pyridylpyrazole
and the cyclo-octadiene groups. The goodness of the
approximation could be inferred from Lax–Rh–Leq bond
angles which are in the range 85.85(7)–100.01(6)ꢀ and
from the sum of the inter-equatorial angles, 359.88(7)ꢀ,
in spite of the narrow byte angle of the pyridyl-pyrazole
chelate group (72.42(7)ꢀ).
P(1)–Rh(1)–N(2)
P(1)–Rh(1)–N(3)
P(1)–Rh(1)–M(1)a
P(1)–Rh(1)–M(2)a
N(2)–Rh(1)–N(3)
N(2)–Rh(1)–M(1)a
N(2)–Rh(1)–M(2)a
N(3)–Rh(1)–M(1)a
N(3)–Rh(1)–M(2)a
a
90.15(5)
92.89(5)
90.81(5)
166.41(5)
72.42(7)
164.77(7)
89.67(7)
122.69(7)
100.01(6)
M(1)–Rh(1)–M(2)a
N(2)–N(1)–C(1)
N(2)–N(1)–C(9)
C(1)–N(1)–C(9)
Rh(1)–N(2)–N(1)
Rh(1)–N(2)–C(7)
Rh(1)–N(3)–C(2)
Rh(1)–N(3)–C(6)
85.85(7)
121.6(2)
110.9(2)
127.5(2)
135.26(15)
118.92(16)
125.96(17)
115.49(15)
M(1) and M(2) represent the midpoints of the olefinic bonds
C(10)–C(11) and C(14)–C(15), respectively.
The most intriguing feature of the structure concerns
˚
the relative long Rh–N(3) bond distance, 2.313(2) A. This
distance is only comparable with values observed for pyri-
dines as axial ligands in lantern complexes of the type
[Rh2(l-RCO2)4(pyR )2] (around 2.25 A) when situated
trans to the metal–metal bond [20,21] or in pentacoordi-
0
˚
nated
Rh(I)-diolefin-pyridine
complexes
(range
˚
2.273(4)–2.320(2) A) containing tridentate pyridine-
amine-pyridine ligands [22,23]. This parameter seems to
reflect the relatively high electron density of the rho-
dium(I) atom in this coordinatively saturated complex

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1639
and its well known tendency to form square-planar
environments.
The cyclo-octadiene molecule is linked to the metal
through the two olefinic bonds showing its usual tub
conformation; however the two double bonds exhibit
very different bonding parameters with Rh–C mean dis-
and at 1965 cmꢀ1, assigned to the dinuclear compound.
For the Ir products only two IR m(CO) stretching bands
are observed, those of the mononuclear complex. The
iridium dinuclear compound is not soluble enough, so
the m(CO) absorption could not be detected.
˚
˚
tances of 2.097(2) A (C(10) and C(11)) and 2.216(2) A
(C(14) and C(15)). The different metal-olefin interaction
is also reflected in the C–C double bonds, which are
2.3. Hydrosilylation reactions
Catalytic hydrosilylation of alkynes is a relevant
process generating important reagents for a number of or-
ganic transformations [24]. The neutral [Ir(pzpy)(COD)]
complex is a modest catalyst for the hydrosilylation of
phenylacetylene with triethylsilane in 1,2-dichloroethane
at 60 ꢀC. After 1420 min, the conversion is 58.5% and the
products formed are cis-PhCH@CH(SiEt3) (42.5%),
trans-PhCH@CH(SiEt3) (18.8%), Ph(SiEt3)C@CH2
(6.6%), PhC”CSiEt3 (19.3%), PhCH@CH2 (9.8%) and
PhCH2–CH3, (9.8%). The amount of PhC”CSiEt3
formed by the dehydrogenative silylation was similar to
that of PhCH@CH2 plus that of PhCH2–CH3. A normal
hydrosilylation together with the dehydrogenative silyla-
tion of phenylacetylene and simultaneous formation of
styrene has been previously observed and rationalized
for the cationic [Ir(iPr2CH2CH2OMe)(COD)][BF4] com-
plex [25]. We have also studied the activity of the cationic
[Ir(Hpzpy)(COD)]+ complex that, although a little bit
faster (66% conversion after 1420 min) produces along
with the normal products of hydrosilylation significant
amounts of ethylbenzene (39.4%).
˚
1.421(4) and 1.374(4) A, respectively. This peculiar
behaviour should be associated to the different p-charac-
ter of the nearly trans ligands (P(1)–Rh–M(2)
166.41(5)ꢀ; N(2)–Rh–M(1) 164.77(7)ꢀ).
2.2. Displacement reactions
The diolefin ligand of complexes 1–7 can easily be
displaced by bubbling carbon monoxide through their
solutions. However, in many cases, the formed
products are not soluble enough to run their NMR
spectra, making difficult their identification. The
low solubility along with the dark colours observed
and the planarity of the species suggest the presence
of electronic interactions due to the stacking in
columns of these metal complexes. These compounds
exhibit low stability both in deoxygenated solutions
and in the solid state and consequently they have to
be kept at low temperature and under inert
atmosphere.
With the pentacoordinated complexes 1 or 3, dark
blue solids, of stoichiometry [MCl(Hpzpy)(CO)2]
(M = Rh or Ir) with four IR m(CO) stretching bands in
the terminal carbonyl region are formed. The products
are not soluble enough to run their NMR spectra. They
are probably mixtures of the pentacoordinated com-
plexes and the ionic compounds with the chlorine atom
out of the coordination sphere.
Cationic compounds 4 and 5 give, under carbonyla-
tion, pure bis-carbonyl complexes [M(Hpzpy)-
(CO)2]Otf (M = Rh, 17; Ir, 18) that can be isolated
and characterised. They are not very soluble but, in
acetone, it is possible to obtain their proton NMR
spectra. They show six signals for the aromatic pro-
tons of the Hpzpy ligand and complex 17 also shows
a wide signal at low field (d 14.3) due to the N–H
proton. Complex 18 is less soluble and the N–H signal
was not observed.
When the neutral complexes 6 or 7, with the deprot-
onated pyrazole, are used their reaction with CO gives
mixtures of dicarbonylated mononuclear products
[M(pzpy)(CO)2] together with dinuclear complexes
[{M(pzpy)(CO)}2] in which the pyrazole is coordinated
as exo bidentate bridge. The solid obtained for
M = Rh shows three IR m(CO) stretching bands at
2085, 2017 cmꢀ1, attributed to the mononuclear species,
3. Experimental
Reactions were routinely carried out by standard
Schlenk-line techniques under an argon atmosphere,
using dioxygen-free solvents unless noted otherwise.
Elemental analyses (C, H, N and S) were carried
out in a Perkin–Elmer 240 C microanalyser. Infrared
spectra (4000–400 cmꢀ1) were recorded on a Nicolet
550 or on Perkin–Elmer 883 (4000–200 cmꢀ1) spectro-
photometers using Nujol mulls between polyethylene
sheets or in solution in NaCl cells. Conductivity mea-
surements were performed, using a Phillips conductiv-
ity bridge, at 20 ꢀC in ca. 5 · 10ꢀ4 M acetone
solutions. FAB mass spectra (m-nitrobenzyl alcohol
matrix) were recorded in a V.G. Autoespec double-
focusing mass spectrometer operating in the positive
mode; high-resolution mass spectra are in accordance
with the simulated isotopic pattern distribution.
NMR spectra were recorded on Varian Gemini
2000, Varian Unity 300 or Bruker ARX 300 spectrom-
eters. Chemical shifts are reported in ppm and the sol-
vents were used as internal reference. The atoms
numbering of the ligand used for NMR descriptions
is as follows:

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1640
H8
C8
127.2 (s, C-4), 123.2 (s, C-3), 121.9 (s, C-5), 105.6 (s, C-8),
70.3 (s, @CH), 33.1 (s, CH2).
H4
H5
C4 C5
H9
C9
H3 C3
C2
C6 C7
N
N
3.2. Synthesis of [M(COD)(Hpzpy)] (CF3SO3)
(M = Rh, 4; M = Ir, 5)
N
H
H2
Thecomplexes[{Rh(l-Cl)(COD)}2][26], [{Rh(l-OMe)-
(COD)}2] [27], [{Ir(l-Cl)(COD)}2] [28], [{Ir(l-OMe)-
(COD)}2] [29], [{Rh(l-Cl)(TFB)}2] [30], [IrCl(TFB)2] [31]
and [{Rh(l-Cl)(CO)2}2] [32] and the ligand [3-(2-pyridi-
nyl)pyrazole] [33,34] were prepared according to the
reported methods.
To CH2Cl2/acetone solutions (10/5 ml) of [{M(l-
Cl)(COD)}2] (0.51 mmol), AgCF3SO3 (260 mg, 1.01
mmol) was added. After 30 min at room temperature
(r.t.), the white solid (AgCl) formed was filtered off,
and the ligand, Hpzpy (148 mg, 1.02 mmol) was added
to the solution. The mixtures were stirred for 15 min.
Partial evaporation of the solvent and addition of diethyl-
ether led to the precipitation of compounds 4 and 5,
which were filtered off, washed with diethylether and
vacuum dried. Data for 4: Yellow, 82% yield. Anal.
Calc. for C17H19F3N3O3RhS: C, 40.41; H, 3.79; N,
8.32; S, 6.35. Found: C, 40.54; H, 3.99; N, 8.34; S,
6.22%. IR (nujol, polyethylene sheets): m(N–H) 3100,
br, cmꢀ1. MS (FAB) m/e 356 [M+, 100]. KM 99.5
3.1. Synthesis of [MCl(diolefin)(Hpzpy)] (M = Rh,
diolefin = COD, 1; M = Rh, diolefin = TFB, 2; M = Ir,
diolefin = COD, 3)
To dichloromethane solutions of [{M(l-Cl)(diole-
fin)}2] (0.40 mmol) Hpzpy (0.116 mg, 0.80 mmol) was
added. The solutions were stirred for 1 h and the solvent
was partially evaporated under reduced pressure. Upon
addition of diethyl ether solids were formed, which were
filtered, washed with diethyl ether and dried under re-
duced pressure. Data for 1: yellow, yield 89%. Anal. Calc.
for C16H19ClN3Rh: C, 49.06; H, 4.89; N, 10.73. Found: C,
48.72; H, 5.31; N, 11.07%. MS (FAB) m/e 356 [(M–Cl)+,
Xꢀ1 cm2 molꢀ1
.
1H NMR (CDCl3), d, 13.6 (br, 1H,
3
N–H), 8.0 (td, JH–H = 7.8 Hz, JH–H = 1.4 Hz, 1H, H-
4
3
3
4), 7.9 (d, JH–H = 2.5 Hz, 1H, H-9), 7.8 (d, JH–H
=
7.6 Hz, 1H, H-5), 7.7 (td, JH–H = 6.4 Hz, JH–H = 1.2
3
3
3
Hz, 1H, H-3), 7.6 (d, JH–H = 5.5 Hz, 1H, H-2) 6.7 (d,
3JH–H = 2.8 Hz, 1H, H-8), 5.1 (br, 2H, @CH), 4.3 (br,
2H, @CH), 2.5 (m, 4H, CH2), 2.1 (m, 4H, CH2). 19F
NMR (CDCl3), d, ꢀ80.6 s. 13C{1H} NMR (CDCl3), d,
152.6 (s, C-7), 152.3 (s, C-6), 147.7 (s, C-2), 140.5 (s,
C-9), 134.4 (s, C-4), 125.1 (s, C-3), 121.5 (s, C-5),
103.4 (s, C-8), 84.7 (br, @CH), 82.4 (br, @CH), 30.6
(br, CH2), 29.9 (br, CH2). Data for 5: Red, 84% yield.
Anal. Calc. for C17H19F3IrN3O3S: C, 34.34; H, 3.22;
N, 7.07; S, 5.39. Found: C, 34.42; H, 3.37; N, 7.18; S,
5.25%. IR (nujol, polyethylene sheets): m(N–H) 3150,
br, cmꢀ1. MS (FAB) m/e 446 [M+, 100]. KM 93
40]. IR (nujol, polyethylene sheets): m(Rh–Cl) 297 cmꢀ1
.
1H NMR (CD2Cl2, ꢀ80 ꢀC), d, 15.2 (br, 1H, N–H), 8.0
3
(t, JH–H = 7.8 Hz, 1H, H-4), 7.8 (2H, H-9 + H-5), 7.6
3
(d, JH–H = 5.3 Hz, 1H, H-2), 7.4 (t, JH–H = 6.4 Hz,
3
3
1H, H-3), 6.8 (d, JH–H = 2.6 Hz, 1H, H-8), 4.7 (br, 4H,
@CH), 2.4 (br, 4H, CH2), 2.0 (m, 4H, CH2). 13C{1H}
NMR (CD2Cl2, ꢀ80 ꢀC), d, 148.1 (s, C-2), 140.4 (s, C-
9), 134.0 (s, C-4), 125.0 (s, C-3), 121.6 (s, C-5), 103.5 (s,
C-8), 83.8 (d, JC–Rh = 12.4 Hz, @CH), 30.8 (s, CH2). Data
for 2: yellow, 70% yield. Anal. Calc. for
C20H13ClF4N3Rh: C, 47.13; H, 2.57; N, 8.24. Found: C,
46.59; H, 2.31; N, 8.04%. MS (FAB) m/e 474 [(M–Cl),
Xꢀ1 cm2 molꢀ1
.
1H NMR (CDCl3), d, 14.1 (br, 1H,
3
N–H), 8.1 (td, JH–H = 7.8 Hz, JH–H = 1.5 Hz, 1H, H-
4
3
4), 8.0 (d, JH–H = 2.7 Hz, 1H, H-9) 7.9 (d, JH–H = 5.7
3
1
3
Hz, 1H, H-2), 7.8 (d, JH–H = 7.5 Hz, 1H, H-5), 7.5
100]. H NMR (CDCl3), d, 15.9 (br, 1H, N–H), 8.0 (t,
3
3
4
3JH–H = 7.2 Hz, 1H, H-4), 7.7 (d, JH–H = 8.1 Hz, 1H,
(td, JH–H = 6.5 Hz, JH–H = 1.2 Hz, 1H, H-3) 6.8 (d,
3JH–H = 2.7 Hz, 1H, H-8), 5.0 (br, 2H, @CH), 4.0 (br,
2H, @CH), 2.3 (br, 4H, CH2), 1.9 (m, 4H, CH2). 19F
NMR (CDCl3), d, ꢀ80.5 s. 13C{1H}NMR (CDCl3), d,
148.2 (s, C-2), 141.3 (s, C-9), 135.8 (s, C-4), 125.8 (s,
C-3), 121.5 (s, C-5), 104.0 (s, C-8), 71.0 (s, @CH), 67.2
(s, @CH), 31.5 (s, CH2), 30.5 (s, CH2).
3
H-5), 7.7 (br, 1H, H-9), 7.4 (d, JH–H = 5.1 Hz, 1H, H-
3
3
2), 7.4 (t, JH–H = 6.6 Hz, 1H, H-3), 6.7 (d, JH–H = 2.4
Hz, 1H, H-8), 5.7 (br, 2H, TFB), 4.5 (br, 4H, TFB). 19
F
NMR (CDCl3), d, ꢀ148.0 m, ꢀ160.1 m. Data for 3:
Red, yield 88%. Anal. Calc. for C16H19ClIrN3: C, 39.95;
H, 3.98; N, 8.74. Found: C, 39.76; H, 3.98; N, 8.74%.
MS (FAB) m/e 480 (M, 15), 446 [(M–Cl), 100]. m(Ir–Cl)
1
235 cmꢀ1. H NMR (CD2Cl2), d, 15.4 (br, 1H, N–H),
3
8.1 (t, JH–H = 7.8 Hz, 1H, H-4), 7.9 (br, 1H, H-2), 7.9
3.3. Synthesis of [M(COD)(pzpy)] (M = Rh, 6;
M = Ir, 7)
3
3
(d, JH–H = 7.9 Hz, 1H, H-5), 7.8 (d, JH–H = 2.2 Hz,
1H, H-9), 7.5 (t, 3JH–H = 6.2 Hz, 1H, H-3), 6.8 (d, 3JH–H
= 2.5 Hz, 1H, H-8), 4.8 (br, 4H, @CH), 2.3 (m, 4H,
CH2), 1.9 (m, 4H, CH2). 13C{1H} RMN (CD2Cl2), d,
156.4 (s, C-7), 150.0 (s, C-6), 143.1 (s, C-2), 137.2 (s, C-9),
The ligand Hpzpy (107 mg, 0.74 mmol) was added
to dichloromethane (15 ml) solutions of [{M(l-OMe)
(COD)}2] (0.37 mmol). The solutions were stirred for

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1641
2 and then the solvent was partially evaporated under
reduced pressure. Upon addition of diethyl ether sol-
ids were formed, which were filtered, washed with
diethyl ether and dried under reduced pressure. Data
for 6: Yellow, 84% yield. Anal. Calc. for C16H18N3Rh:
C, 54.10; H, 5.11; N, 11.83. Found: C, 54.10; H, 5.04;
105.8 (s, C-8), 87.6 (s, @CH), 85.9 (s, @CH), 32.4
(s, CH2), 32.3 (s, CH2).
3.5. Synthesis of cis-[IrCl2(COD)(pzpy)] (9)
To a dichloromethane solution of 7 (100 mg, 0.22
mmol) [AuCl(tht)] (144 mg, 0.44 mmol) was added.
After 20 min the solution darkened and a black solid
(metallic gold) was deposited on the Schlenk walls.
The suspension was kept stirring for two days and
the black solid was filtered through kieselguhr giving
a yellow solution. Most of the solvent was removed
under reduced pressure and diethyl ether was added
yielding a yellow solid, which was filtered, washed
with diethyl ether and vacuum dried. Yield 62%. Anal.
Calc. for C16H18Cl2IrN3: C, 37.28; H, 3.52; N, 8.15.
Found: C, 37.33; H, 3.60; N, 8.10%. IR (nujol, poly-
1
N, 11.89%. MS (FAB) m/e 356 [MH+, 100]. H NMR
3
4
(CDCl3, ꢀ55 ꢀC) d, 7.7 (td, JH–H = 7.8 Hz, JH–H
=
1.5 Hz, 1H, H-4), 7.6 (d, JH–H = 1.8 Hz, 1H,
3
3
H-9), 7.5 (d, JH–H = 6.3 Hz, 1H, H-2), 7.5 (d,
3
3JH–H = 9.0 Hz, 1H, H-5), 7.0 (td, JH–H = 6.5 Hz,
3
4JH–H = 1.2 Hz, 1H, H-3), 6.4 (d, JH–H = 1.8 Hz,
1H, H-8), 5.0 (br, 2H, @CH), 4.1 (br, 2H, @CH),
2.5 (m, 4H, CH2), 2.0 (br, 4H, CH2). 13C{1H}
RMN (CDCl3, ꢀ55 ꢀC), d, 154.7 (s, C-7), 151.1 (s,
C-6), 146.7 (s, C-2), 141.0 (br, C-9), 139.4 (s, C-4),
121.6 (s, C-3), 119.3 (s, C-5), 102.3 (s, C-8), 82.6 (d,
JC–Rh = 12.1 Hz, @CH), 80.8 (d, JC–Rh = 11.1 Hz,
@CH), 30.3 (s, CH2). Data for 7: Red, 93% yield.
Anal. Calc. for C16H18IrN3: C, 43.23; H, 4.08; N,
9.45. Found: C, 42.97; H, 4.17; N, 9.38%. MS
(FAB) m/e 446 [MH+, 100]. 1H NMR (CDCl3), d,
ethylene sheets): m(Ir–Cl) 276 cmꢀ1
.
1H NMR
3
(CDCl3), d, 9.5 (d, JH–H = 6.2 Hz, 1H, H-2),
7.9–7.7 (3H, H-4 + H-5 + H-9), 7.2 (td, JH–H = 6.7
3
4
3
Hz, JH–H = 1.8 Hz, 1H, H-3), 6.8 (d, JH–H = 2.1
Hz, 1H, H-8), 6.7 (m, 1H, @CH), 6.0 (m, 1H,
@CH), 5.3 (m, 1H, @CH), 4.1 (m, 1H, @CH),
3.4–1.4 (8H, CH2). 13C{1H} NMR (CDCl3), d, 154.3
(s, C-7), 147.7 (s, C-2), 146.1 (s, C-6), 141.9 (s, C-9),
139.7 (s, C-4), 121.4 (s, C-3), 119.9 (s, C-5), 105.8
(s, C-8), 103.7 (s, @CH), 102.1 (s, @CH), 97.7 (s,
@CH), 97.3 (s, @CH), 32.3 (s, CH2), 32.1 (s, CH2),
29.0 (s, CH2), 28.4 (s, CH2).
3
7.8 (2H, H-2 + H-4), 7.6 (d, JH–H = 1.8 Hz, 1H, H-
3
9), 7.5 (dd, JH–H = 8.7 Hz, JH–H = 1.2 Hz, 1H, H-
4
3
5), 7.1 (td, JH–H = 6.6 Hz, JH–H = 1.2 Hz, 1H, H-
4
3
3), 6.4 (d, JH–H = 1.8 Hz, 1H, H-8), 4.9 (br, 2H,
@CH), 3.7 (br, 2H, @CH), 2.3 (m, 4H, CH2), 1.8
(m, 4H, CH2). 13C{1H} NMR (CDCl3), d, 157.1 (s,
C-7), 153.7 (s, C-6), 147.0 (s, C-2), 142.3 (s, C-9),
140.1 (s, C-4), 121.8 (s, C-3), 118.9 (s, C-5), 103.0
(s, C-8), 68.0 (br, @CH), 63.7 (br, @CH), 31.1 (s,
CH2).
3.6. Synthesis of [Ir(Me)I(COD)(pzpy)] (10)
The addition of iodomethane (0.5 ll, 8.0 mmol) to
a red dichloromethane solution of 7 (50 mg, 0.11
mmol) gave a yellow-orange suspension, in 10 min.
Half of the solvent was evaporated under reduced
pressure. Upon addition of diethyl ether a yellow solid
was formed, which was filtered, washed with diethyl
ether and dried under reduced pressure. The product
was recrystallised from dichloromethane-diethyl ether.
Yield 58%. Anal. Calc. for C17H21IIrN3: C, 34.82;
H, 3.61; N, 7.58. Found: C, 35.09; H, 3.66; N,
7.16%. MS (FAB) m/e 588 [M, 100]. 1H NMR
(CDCl3), d, 7.8–7.7 (3H, H-2 + H-4 + H-5), 7.6 (d,
3.4. Synthesis of trans-[IrI2(COD)(pzpy)] (8)
Iodine (45 mg, 0.18 mmol) was added to a dichlo-
romethane solution of 7 (75 mg, 0.17 mmol) and the
mixture was stirred for 4.5 h giving a red suspension.
The solvent was evaporated under reduced pressure
till a small volume. Upon addition of diethyl ether a
red solid was formed, which was filtered, washed with
diethyl ether and dried under reduced pressure. The
product was recrystallised from dichloromethane-
diethyl ether. Yield 60%. The data are for the trans
isomer, which was obtained in a 98% proportion.
Anal. Calc. for C16H18I2IrN3: C, 27.52; H, 2.60; N,
3
3JH–H = 2.1 Hz, 1H, H-9), 7.1 (td, JH–H = 6.0 Hz,
3
4JH–H = 1.6 Hz, 1H, H-3), 6.7 (d, JH–H = 2.1 Hz,
1
3
6.02. Found: C, 27.42; H, 2.63; N, 5.94%. H NMR
3
1H, H-8), 5.8 (t, JH–H = 7.1 Hz, 1H, @CH), 5.2
4
3
(CDCl3), d, 7.8 (dt, JH–H = 5.7 Hz, JH–H = 0.9 Hz,
1H, H-2), 7.8 (2H, H-4 + H-5), 7.6 (d, JH–H = 2.4
(t, JH–H = 7.1 Hz, 1H, @CH), 4.8 (m, 1H, @CH),
3
4.3 (m, 1H, @CH), 3.2–2.0 (8H, CH2), 1.8 (s, 3H,
Me). 13C{1H} NMR (CDCl3), d, 155.6 (s, C-7), 147.8
(s, C-6), 146.4 (s, C-2), 141.0 (s, C-9), 139.3 (s, C-4),
121.7 (s, C-3), 120.8 (s, C-5), 104.7 (s, C-8), 83.6
(s, @CH), 82.8 (s, @CH), 82.2 (s, @CH), 81.8
(s, @CH), 33.5 (s, CH2), 32.9 (s, CH2), 27.9 (s,
CH2), 27.5 (s, CH2), 9.0 (s, Me).
3
Hz, 1H, H-9), 7.1 (td, JH–H = 5.9 Hz, JH–H = 3.0
4
3
Hz, 1H, H-3), 6.8 (d, JH–H = 2.1 Hz, 1H, H-8), 6.2
(m, 2H, @CH), 5.7 (m, 2H, @CH), 3.1 (m, 4H,
CH2), 3.0–2.8 (4H, CH2). 13C{1H} NMR (CDCl3),
d, 156.8 (s, C-7), 149.6 (s, C-6), 148.2 (s, C-2), 142.0
(s, C-9), 140.1 (s, C-4), 122.3 (s, C-3), 121.0 (s, C-5),

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1642
3
4), 7.5 (d, JH–H = 8.1 Hz, 1H, H-5), 7.3–7.1 (m, 15 H,
3
PPh3), 6.5 (d, JH–H = 2.5 Hz, 1H, H-8), 4.2 (s, 3 H,
3.7. Synthesis of [M(Mepzpy)(COD)](Otf) (M = Rh,
11; M = Ir, 12)
Me–N), 3.8 (br, 4H, @CH), 2.5 (m, 4H, CH2), 1.9 (m,
4H, CH2). 13C NMR (CDCl3), d, 151.0 (s, C2), 150.1
(s, C6), 149.8 (s, C7), 138.4 (s, C9), 136.3 (s, C4),
MeOtf (32 ll, 0.28 mmol) was added to dichlorome-
thane (15 ml) solutions of [M(COD)(pzpy)] (6 or 7) (100
mg, 0.28 mmol for 6, 127 mg, 0.28 mmol for 7). The
solutions were stirred for 2 h and 3/4 of the solvent
was evaporated under reduced pressure. Upon addition
of 15 ml of diethyl ether solids were formed, which were
filtered, washed with diethyl ether and dried under re-
duced pressure. The products were recrystallised from
dichloromethane/diethyl ether. They are no stable and
have to be kept under argon atmosphere and at low tem-
perature. Data for 11: Yellow, 81% yield. Anal. Calc. for
C18H21F3N3O3RhS: C, 41.63; H, 4.08; N, 8.09; S, 6.17.
Found: C, 41.70; H, 4.01; N, 7.85; S, 5.93%. MS
(FAB) m/e 370 [M+, 100]. KM (acetone) 107 Xꢀ1 cm2
2
133.2 (d, o-C, PPh3, JC–P = 10 Hz), 130.4 (s, p-C,
1
PPh3), 129.7 (d, ipso-C, PPh3, JC–P = 37.7 Hz), 128.4
3
(d, m-C, PPh3, JC–P = 8.8 Hz), 124.7 (s, C3), 122.1 (s,
C5), 105.4 (s, C8), 80.8 (s, @CH, COD), 40.3 (s, Me–
N), 31.1 (s, CH2, COD).31P NMR (20 ꢀC, CDCl3), d,
1
28.0 (br); (ꢀ60 ꢀC, CDCl3), d, 32.7 (d, JRh-P = 129.6
Hz). 19F NMR (CDCl3), d, ꢀ80.0 (s, 19F). Data for
14: Yellow; yield 70%. Anal. Calc. for C36H36F3Ir-
N3O3PS: C, 49.64; H, 4.14; N, 4.82; S, 3.70. Found: C,
49.04; H, 3.99; N, 4.70; S, 3.68%. MS (FAB) m/e
721 [M+, 15], 460 [(Ir(Mepzpy)(COD))+, 100]. KM
1
75 X ꢀ1 cm2 molꢀ1. H NMR (CDCl3), d, 9.0 (2H, H-
3
4 + H-5), 8.0 (d, JH–H = 2.7 Hz, 1H, H-9), 7.8 (td,
molꢀ1. KM (dichloromethane) 47 Xꢀ1 cm2 molꢀ1
.
1H
3
4
4
NMR (CDCl3), d, 8.0 (td, JH–H = 7.8 Hz, JH–H = 1.5
Hz, 1H, H-4), 7.9 (d, JH–H = 8.1 Hz, 1H, H-5), 7.9 (d,
3JH–H = 7.7 Hz, JH–H = 1.5 Hz, 1H, H-3), 7.6 (d,
3JH–H = 7.5 Hz, 1H, H-2), 7.2 (m, 15 H, PPh3), 6.7 (d,
3JH–H = 2.7 Hz, 1H, H-8), 4.2 (s, 3H, Me–N), 3.2 (br,
4H, @CH), 2.4 (m, 4H, CH2), 1.8 (m, 4H, CH2). 13C
NMR (CDCl3), d, 152.1 (s, C6), 151.7 (s, C2), 151.5 (s,
C7), 138.6 (s, C9), 136.4 (s, C4), 133.1 (d, o-C, PPh3,
2JC–P = 10.25 Hz), 130.6 (s, p-C, PPh3), 128.9 (d, ipso-
3
3
3JH–H = 2.7 Hz, 1H, H-9), 7.6 (d, JH–H = 5.7 Hz, 1H,
3
H-2), 7.4 (td, JH–H = 6.5 Hz, JH–H = 1.5 Hz, 1H,
4
3
H-3), 6.9 (d, JH–H = 2.7 Hz, 1H, H-8), 4.7 (br, 4H,
@CH), 3.8 (s, 3H, Me), 2.6 (m, 4H, CH2), 2.0 (m, 4H,
CH2). Data for 12: Red, 86% yield. Anal. Calc. for
C18H21F3IrN3O3S: C, 35.52; H, 3.48; N, 6.90; S, 5.27.
Found: C, 35.52; H, 3.09; N, 6.81; S, 4.92%. MS
(FAB) m/e 460 [M+, 100]. KM (acetone) 100 Xꢀ1 cm2
1
C, PPh3, JC–P = 38.5 Hz), 128.4 (d, m-C, PPh3,
3JC–P = 9.51 Hz), 125.1 (s, C3), 122.2 (s, C5), 105.9 (s,
C8), 63.7 (s, @CH, COD), 40.5 (s, Me–N), 32.3 (s,
CH2, COD). 31P NMR (CDCl3), d, 10.4 (s, 31P). 19F
NMR (CDCl3), d, ꢀ80.0 (s, 19F).
1
molꢀ1. H NMR (CDCl3), d, 8.1 (2H, H-4 + H-5), 8.0
3
(d, JH–H = 2.7 Hz, 1H, H-9), 7.9 (d, JH–H = 5.7 Hz,
3
3
1H, H-2), 7.5 (td, JH–H = 6.0 Hz, JH–H = 2.7 Hz, 1H,
4
3
H-3), 7.1 (d, JH–H = 2.7 Hz, 1H, H-8), 4.5 (br, 4H,
3.9. Synthesisof [M(Mepzpy)(P(OMe)3)(COD)](Otf)
(M = Rh, 15; M = Ir, 16)
@CH), 3.9 (s, 3H, Me), 2.4 (m, 4H, CH2), 1.8 (m, 4H,
CH2). 13C{1H} NMR (CDCl3), d, 146.8 (s, C-2), 142.2
(s, C-9), 139.8 (s, C-4), 126.1 (s, C-3), 122.8 (s, C-5),
106.2 (s, C-8), 31.2 (s, CH2), 22.3 (s, Me).
To dichloromethane solutions (15 ml) of 11 or 12
(0.19 mmol) P(OMe)3 (22.73 ll, 0.19 mmol) was added
very slowly. The solutions were stirred (3 h for the rho-
dium complex and 3 min for the iridium complex), the
solvent was partially removed and the addition of hex-
ane or diethyl ether led to yellow solids, which were fil-
tered, washed with hexane and vacuum dried. Complex
16 has to be kept under argon at low temperature. Data
for 15: Yellow, 72% yield. Anal. Calc. for
C21H30F3N3O6PRhS: C, 39.19; H, 4.66; N, 6.53; S,
4.97. Found: C, 38.84; H, 4.35; N, 6.20; S, 4.47%. KM
3.8. Synthesis of [M(Mepzpy)(PPh3)(COD)](Otf)
(M = Rh, 13; M = Ir, 14)
To dichloromethane solutions (15 ml) of 11 or 12
(0.20 mmol) PPh3 (52.46 mg, 0.20 mmol) was added.
The solutions were stirred for 15 min, the solvent was
partially removed and the addition of hexane led to yel-
low solids, which were filtered, washed with hexane and
vacuum dried. Complex 14 is not stable in solution and
in the solid state has to be kept under argon at low tem-
perature. Data for 13: Yield 74%. Anal. Calc. for
C36H36F3N3O3PRhS: C, 55.32; H, 4.61; N, 5.38; S,
4.09. Found: C, 54.90; H, 4.31; N, 5.36; S, 3.80%. MS
(FAB) m/e 524 [(Rh(Mepzpy)(PPh3))+, 15], 370
[(Rh(Mepzpy)(COD))+, 100], 262 [Rh(Mepzpy)+, 25].
91 Xꢀ1 cm2 molꢀ1
.
1H NMR (CDCl3), d, 8.1 (td,
4
3JH–H = 7.5 Hz, JH–H = 1.3 Hz 1H, H-4), 7.9 (d,
3JH–H = 7.3 Hz, 1H, H-5), 7.8 (d, JH–H = 2.3 Hz, 1H,
3
3
H-9), 7.6 (d, JH–H = 5.2 Hz, 1H, H-2), 7.4 (td,
4
3JH–H = 6.3 Hz, JH–H = 1.5 Hz, 1H, H-3), 6.9 (d,
3JH–H = 2.8 Hz, 1H, H-8), 5.0 (br, 4H, @CH), 4.1 (s,
Me–N), 3.9 (d, JH–P=12.4 Hz, 9-H, O–CH3), 2.7 (m,
3
4H, CH2), 2.2 (m, 4H, CH2). 31P NMR (CDCl3), d,
1
KM 84 Xꢀ1 cm2 molꢀ1
.
1H NMR (CDCl3), d, 8.8 (d,
143.4 (d, JP–Rh = 275.4 Hz). 19F NMR (CDCl3), d,
3
3JH–H = 5.1 Hz, 1H, H-2), 8.0 (d, JH–H = 2.5 Hz, 1H,
ꢀ80.1 (s). Data for 16: White-yellow, 70% yield. Anal.
3
H-9), 7.8 (td, JH–H = 8.5 Hz, JH–H = 1.3 Hz, 1H, H-
4
Calc. for C21H30F3IrN3O6PS: C, 34.41; H, 4.09; N,

´
A.P. Martınez et al. / Inorganica Chimica Acta 358 (2005) 1635–1644
1643
Table 2
Crystal data and structure refinement parameters for complex 13
5.74; S, 4.37. Found: C, 34.04; H, 3.87; N, 5.60; S,
4.18%. MS (FAB) m/e 584 [M+, 10], 460 [(Ir(Mepzpy)-
(COD))+, 100]. KM 85 Xꢀ1 cm2 molꢀ1 1H NMR
Empirical formula
Formula weight
Crystal system
Space group
C36H36F3N3O3PSRh Æ CH2Cl2
866.54
.
3
(CDCl3), d, 9.2 (2H, H-4 + H-5), 8.0 (d, JH–H = 2.5
Hz, 1H, H-9), 7.9 (d, JH–H = 5.4 Hz, 1H, H-2), 7.5
orthorhombic
Pbcn
3
3
(td, JH–H = 6.1 Hz, JH–H = 1.8 Hz, 1H, H-3), 7.0 (d,
4
˚
a (A)
35.0719(12)
11.8495(4)
18.4056(6)
1
3JH–H = 2.5 Hz, H, H-8), 4.4 (br, 4H, @CH), 4.3 (s,
Me–N), 3.4 (d, JH–P = 11.11 Hz, 9-H, O–CH3), 2.4
˚
b (A)
3
˚
c (A)
3
˚
(m, 4H, CH2), 2.1 (m, 4H, CH2). 31P NMR (CDCl3),
V (A )
7649.1(4)
8
1.505
Z
d, 86.9 (s). 19F NMR (CDCl3), d, ꢀ80.11 (s).
Dcalc (g cmꢀ3
l (mmꢀ1
Crystal size (mm)
)
)
0.737
0.09 · 0.06 · 0.02
2.07–27.51
3.10. Synthesis of [M(CO)2(Hpzpy)](CF3SO3)
(M = Rh, 17; M = Ir, 18)
hmax (ꢀ)
Index ranges
ꢀ46 6 h 6 46, ꢀ14
6 k 6 15, ꢀ24 6 l 6 24
60 020
Through acetone or dichloromethane solutions (10 ml)
of 4 or 5 (0.20 mmol), respectively, CO (1 atm, r.t.) was
bubbled for 50 min; complexes 17 and 18 were forming
as orange and green solids. To complete the precipitation
of the complexes diethyl ether was added to the solution.
The solids were filtered off under argon atmosphere,
washed with diethyl ether and vacuum dried. Both com-
plexes are not stable to the air or to the temperature so
they have to be kept under argon and in the fridge. Com-
pound 18 is not soluble enough to run its 13C NMR. Data
for 17: Orange; yield 65%. Anal. Calc. for
C11H7F3N3O5RhS: C, 26.51; H, 1.56; N, 9.27; S, 7.08.
Found: C, 27.03; H, 1.70; N, 9.34; S, 7.18%. IR (nujol,
polyethylene sheets, cmꢀ1): m(N–H) 3120, br; m(CO)
2105, 2046. IR (CH2Cl2): m(CO) 2104, 2042. KM 104
Reflections measured
Independent reflections
Maximum and minimum transmission 0.9854 and 0.9366
9450 [Rint = 0.0504]
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
R indices (all data)
9450/0/594
1.043
R1 = 0.0358, wR2 = 0.0899
R1 = 0.0484, wR2 = 0.0950
0.810 and ꢀ0.622
ꢀ3
˚
Largest peak and hole (e A
)
(11088 ref.). During data collection instrument and crys-
tal stability was evaluated from measurement of equiva-
lent reflections at different measuring times; no
important variations were observed. Intensities were
integrated from several series of exposure frames cover-
ing the whole reciprocal space [35]. Data were corrected
for Lorentz and polarisation effects, and a semi-empiri-
cial absorption correction, based on repeated and sym-
metry-equivalent reflections, was also applied [36].
The structure was solved by direct methods and
completed by successive difference Fourier syntheses.
Anisotropic displacement parameters were used for all
non-hydrogen atoms. Hydrogen atoms were included
from observed positions and refined as free isotropic
atoms (except those of the methyl group, which were re-
fined with riding positional and displacement parame-
ters). A dichloromethane solvent molecule was also
detected in the crystal structure; its carbon atom was
observed disordered and split in two complementary
positions. Refinements were carried out by full-matrix
least-squares on F2 for all data [37]. Final agreement fac-
tors are collected in Table 2. All the residual peaks in the
Xꢀ1 cm2 molꢀ1 1H NMR (HDA), d, 14.3 (br, 1H,
.
3
N–H), 8.9 (d, JH–H = 5.1 Hz, 1H, H-2), 8.4 (2H, H-
3
3
5 + H-4), 8.3 (d, JH–H = 2.7 Hz, 1H, H-9), 7.8 (t, JH–H
=
5.7, 1H, H-3), 7.4 (d, JH–H = 2.7, 1H, H-8). 19F NMR
(HDA), d, ꢀ74.4 s. 13C NMR (HDA), d, 155.2 (s,
C-2), 143.4 (s, C-9), 136.2 (s, C-4), 127.5 (s, C-3),123.5
(s, C-5), 105.7 (s, C-8). Data for 18: Green, 72% yield.
Anal. Calc. for C11H7F3IrN3O5S: C, 22.14; H, 1.30; N,
7.75; S, 5.91. Found: C, 22.92; H, 1.56; N, 7.58; S,
5.41%. IR (nujol, polyethylene sheets, cmꢀ1): m(CO)
3
2077, 2031. KM 97.0 Xꢀ1 cm2 molꢀ1. H NMR (HDA),
d, 9.1 (d, JH–H = 5.1 Hz, 1H, H-2), 8.6–8.5 (2H, H-
4 + H-5), 8.4 (d, JH–H = 3.0 Hz, 1H, H-9), 7.9
(td, JH–H = 6.5 Hz, JH–H = 1.8 Hz, 1H, H-3), 7.5 (d,
3JH–H = 2.7 Hz, 1H, H-8). 19F NMR (HDA), d, ꢀ76.0 s.
1
3
3
3
4
final difference map were below 1 e Aꢀ3. Atomic scatter-
˚
ing factors, corrected for anomalous dispersion, were
used as implemented in the refinement program [37].
3.11. X-ray structural analysis of complex 13
A summary of crystal data and refinement parame-
ters is reported in Table 2. Data for the complex were
obtained at 150(1) K from a BrukerAXS SMART
APEXII CCD diffractometer installed at station 9.8 of
the SRS Daresbury laboratory. Radiation was mono-
4. Supplementary material
Crystallographic data has been deposited with the
Cambridge Data Centre (Deposition no. CCDC
247480). Copies of the information can be obtained
from the Director (E-mail: deposit@ccdc.cam.ac.uk or
http://www.ccdc.cam.ac.uk).
˚
chromated with a silicon 111 crystal (k = 0.69340 A);
data were collected using narrow frames (0.3ꢀ in x). Cell
parameters were refined from the observed setting angles
and detector positions of a set of strong reflections

´
A.P. Martınez et al. / Inorganica Chimica Acta 358 (2005) 1635–1644
1644
[17] D. Carmona, C. Vega, F.J. Lahoz, R. Atencio, L.A. Oro, M.P.
Acknowledgements
´
Lamata, F. Viguri, E. San Jose, Organometallics 19 (2000) 2273.
[18] H. Friebolin, Basic One- and Two-Dimensional NMR Spectrs-
copy, VCH, 1991.
Authors thank CCLRC Daresbury Laboratory for
allocation of synchrotron beam time (AP42). M.J.F.
thanks the MCyT for a grant. The generous financial
support from MEC (Project BQU2002-1729) is grate-
fully acknowledged.
[19] J. Elguero, in: A.R. Katritzky, C.W. Rees (Eds.), Comprehensive
Heterocyclic Chemistry, vol. 5, Pergamon Press, New York, p.
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[20] See for instance: D.F. Taber, S.C. Malcolm, K. Bieger, P.
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´
¨
¨