Synthesis and reactivity of trifluoromethyl isocyanide rhodium(I) complexes

Article abstract of DOI:10.1021/om050573q

The complex trans- [Rh(CF₃)(CNXy)₂(PPh₃)] (1) reacts with SO₂, tetracyanoethylene (TCNE), or maleic anhydride (MA) to give the complexes [Rh(CF₃)(CNXy)₂(PPh ₃)L] (L = SO₂ (2), TCNE (3), MA (4)) and with CO or CF₃CO₂H to give, respectively, mixtures containing mainly [Rh(CF₃)(CNXy)₂(CO)(PPh₃)] or trans-[Rh(CNXy)₂(PPh₃)₂]CF₃CO ₂, which is prepared in better yield by reaction of trans-[RhCl(PPh₃)₂(CO)] with XyNC and NaCF ₃-CO₂. [Rh(CF₃)(CNXy)₃] (6) is prepared by reaction of [Rh(CF₃)(CNXy)₃(PPh₃)] (7) with 35% H₂O₂ or, better, by reaction of [Rh(μ-OH)(COD)]₂ with XyNC and Me₃SiCF₃. The reaction of 6 with tetracyanoethylene (TCNE) or maleic anhydride (MA) gives the complexes [Rh(CF₃)-(CNXy)₃L] (L = TCNE (8), MA (9)). The oxidative addition reaction of Mel or n-C₄F₉I with complex 6 gives the octahedral Rh(III) complexes [Rh(CF₃)(R)I(CNXy) ₃] (R = Me (10), n-C₄F₉ (11)). In an attempt to obtain single crystals of complex 11, a few crystals of [{Rh(CF ₃)(n-C₄F₉)(CNXy)₂} ₂(μ-I)₂] (12) were obtained. The crystal structures of complexes 2-4 and 12 have been determined by X-ray diffraction studies.

Full text of DOI:10.1021/om050573q

5634
Organometallics 2005, 24, 5634-5643
Synthesis and Reactivity of Trifluoromethyl Isocyanide
Rhodium(I) Complexes§
Jose´ Vicente,*,† Juan Gil-Rubio,*,† Juan Guerrero-Leal,† and Delia Bautista‡
Grupo de Quı´mica Organometa´lica, Departamento de Quı´mica Inorga´nica,
Facultad de Quı´mica, and SACE, Universidad de Murcia, Apartado de correos 4021,
E-30071 Murcia, Spain
Received July 8, 2005
The complex trans-[Rh(CF3)(CNXy)2(PPh3)] (1) reacts with SO2, tetracyanoethylene
(TCNE), or maleic anhydride (MA) to give the complexes [Rh(CF3)(CNXy)2(PPh3)L] (L )
SO2 (2), TCNE (3), MA (4)) and with CO or CF3CO2H to give, respectively, mixtures
containing mainly [Rh(CF3)(CNXy)2(CO)(PPh3)] or trans-[Rh(CNXy)2(PPh3)2]CF3CO2, which
is prepared in better yield by reaction of trans-[RhCl(PPh3)2(CO)] with XyNC and NaCF3-
CO2. [Rh(CF3)(CNXy)3] (6) is prepared by reaction of [Rh(CF3)(CNXy)3(PPh3)] (7) with 35%
H2O2 or, better, by reaction of [Rh(µ-OH)(COD)]2 with XyNC and Me3SiCF3. The reaction of
6 with tetracyanoethylene (TCNE) or maleic anhydride (MA) gives the complexes [Rh(CF3)-
(CNXy)3L] (L ) TCNE (8), MA (9)). The oxidative addition reaction of MeI or n-C4F9I with
complex 6 gives the octahedral Rh(III) complexes [Rh(CF3)(R)I(CNXy)3] (R ) Me (10), n-C4F9
(11)). In an attempt to obtain single crystals of complex 11, a few crystals of [{Rh(CF3)(n-
C4F9)(CNXy)2}2(µ-I)2] (12) were obtained. The crystal structures of complexes 2-4 and 12
have been determined by X-ray diffraction studies.
Introduction
have shown that perfluoroalkyl complexes can be ob-
tained under very mild conditions by reaction of (per-
fluoroalkyl)trimethylsilanes with fluoro complexes12-14
or with chloro or bromo complexes in the presence of
There is a demand for selective synthetic methods of
highly fluorinated organic compounds.1 In recent years,
transition-metal perfluoroorganometallic chemistry has
emerged as a promising alternative for the synthesis
and functionalization of fluoroorganic compounds. In
this context, C-F bond activation by metal complexes2
is a major goal that has been achieved in stoichiometric3
or catalytic reactions.4 The use of perfluoroorganome-
tallic compounds for C-C coupling reactions is also a
desirable goal, but it is limited by the thermodynamic
stability and kinetic inertness of the M-RF bond (M )
transition metal, RF ) highly fluorinated alkyl, aryl, or
alkenyl) with respect to its nonfluorinated analogues.5-8
Despite this limitation, C-RF bond formation has been
reported in highly fluorinated aryl, alkenyl, or alkyl
complexes9,10 or in transition-metal-catalyzed coupling
reactions.9,11
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In consequence, the synthesis and reactivity of new
types of perfluoroorganometallic complexes are of inter-
est, especially for complexes of low-oxidation-state met-
als, which cannot be prepared by oxidative addition
reactions with perfluoroalkyl halides.5,6 Recent studies
§ Dedicated to Dr. Jose´ Antonio Abad, with best wishes, on the
occasion of his retirement.
* To whom correspondence should be addressed. Tel and fax: (34)
968 364143. Web address: http://www.um.es/gqo/. E-mail: jvs1@um.es
(J.V.), jgr@um.es (J.G.-R.).
† Departamento de Qu´ımica Inorga´nica, Universidad de Murcia.
‡ SACE, Universidad de Murcia.
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10.1021/om050573q CCC: $30.25 © 2005 American Chemical Society
Publication on Web 10/13/2005

Reactivity of Rh(I) Trifluoromethyl Complexes
Organometallics, Vol. 24, No. 23, 2005 5635
fluoride ions.8,15 Thus, we have reported the synthesis
of a series of new perfluoroalkyl rhodium(I) complexes,
[RhRF(COD)(PR3)] (RF ) CF3, n-C3F7; R ) Ph, C6H4-
OMe-4), and their reactions with isocyanides, to give
[RhRF(CNR′)x(PR3)] (x ) 2, 3, R′ ) 2,6-dimethylphenyl
(Xy), t-Bu, RF ) CF3, i-C3F7).13,14 Previous studies have
shown that these complexes are fairly reactive. For
example, the complexes trans-[Rh(CF3)(CNXy)2(PR3)]
react at room temperature with atmospheric O2 or with
XyNC to give the peroxo complex [Rh(CF3)(η2-O2)-
(CNXy)2(PR3)] or the pentacoordinate complex [Rh(CF3)-
(CNXy)3(PR3)]. Despite the fact that the low reactivity
of the metal-trifluoromethyl bond is well known,5-8 the
electron-rich Rh(I) center may increase the reactivity
of the Rh-C and R-C-F bonds. In the search for new
rhodium(I)-mediated C-C bond formation processes
involving perfluoroorganic substrates, we have explored
the chemical behavior of the complexes trans-[Rh(CF3)-
(CNXy)2L] (L ) PPh3 (1),13 XyNC (6)) toward different
types of reagents, including the results of oxidative
addition reactions which gave trifluoromethyl isocyanide
Rh(III) complexes.
Scheme 1
oxidative addition of an Ar-CF3 compound to a Rh(I)
complex21 or by the reaction of [RhHCl2(PPh3)2] with
Hg(CF3)2, which gave a mixture of [RhCl2(CF3)(PPh3)2]
and [RhCl2(CF2H)(PPh3)2].22 Some of them undergo
interesting selective C-F activation reactions under
very mild conditions.19,21-23 Despite the fact that the
oxidative addition reactions to Rh(I) complexes have
been intensively studied, the oxidative additions to Rh-
(I) perfluoroalkyl complexes are very rare. We are only
aware of reactions of trans-[Rh(CF3)(CO)(PPh3)2] with
X2 (X ) Cl, Br, I), HCl, and MeI. The last compound
gave [Rh(CF3){C(O)Me}I(PPh3)2] instead of the methyl
complex.22 In this context, the synthesis of mixed alkyl-
perfluoroalkyl or bis(perfluoroalkyl) complexes of Rh-
(III) is of particular interest, because no examples of
such compounds have been described and they are
potential candidates for the observation of C-C bond
formation and C-F bond activation processes.
Most Rh(III) perfluoroalkyl complexes have been
prepared by oxidative addition of RF-I to Rh(I) pre-
cursors,16-20 but they have also been prepared by
(5) Bruce, M. I.; Stone, F. G. A., Fluorocarbon Complexes of
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T.; Noveski, D.; Braun, T.; Neumann, B.; Stammler, A.; Stammler, H.-
G. Dalton Trans. 2004, 4106. Hughes, R. P.; Zhang, D.; Zakharov, L.
N.; Rheingold, A. L. Organometallics 2002, 21, 4902.
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Kitazume, T.; Nakajima, S. J. Fluorine Chem. 2004, 125, 1447. Frohn,
H.-J.; Adonin, N. Y.; Bardin, V. V.; Starichenko, V. F. J. Fluorine Chem.
2002, 117, 115. Casado, A. L.; Espinet, P.; Gallego, A. M.; Mart´ınez-
Ilarduya, J. M. Chem. Commun. 2001, 339. Albe´niz, A. C.; Espinet,
P.; Mart´ın-Ruiz, B.; Milstein, D. J. Am. Chem. Soc. 2001, 123, 11504.
Albe´niz, A. C.; Espinet, P.; Mart´ın-Ruiz, B.; Milstein, D. Organome-
tallics 2005, 24, 3679. Perutz, R. N.; Sladek, M. I. Chem. Commun.
2001, 2254. Edelbach, B. L.; Kraft, B. M.; Jones, W. D. J. Am. Chem.
Soc. 1999, 121, 10327.
Results and Discussion
Synthesis. The reaction of trans-[Rh(CF3)(CNXy)2-
(PPh3)] (1) with excess SO2 gave [Rh(CF3)(CNXy)2-
(PPh3)(SO2)] (2) as the main reaction product, which was
isolated in 91% yield (Scheme 1). A single-crystal X-ray
diffraction analysis showed that the SO2 ligand in 2 is
coordinated by the S atom and possesses a pyramidal
geometry (see Figure 1; for a detailed description of the
structures see Crystallographic Studies).
(12) Taw, F. L.; Scott, B. L.; Kiplinger, J. L. J. Am. Chem. Soc. 2003,
125, 14712. Huang, D.; Koren, P. R.; Folting, K.; Davidson, E. R.;
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K. G. J. Am. Chem. Soc. 1997, 119, 3185. Tyrra, W.; Naumann, D. J.
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Organometallics 2004, 23, 4871.
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2636.
Complex 1 did not react with ethylene and norbornene
at room temperature, but it did react with olefins
containing electron-withdrawing groups such as tetra-
cyanoethylene (TCNE) and maleic anhydride (MA) to
give the pentacoordinate complexes [Rh(CF3)(CNXy)2-
(PPh3)L] (L ) TCNE (3), MA (4)), which were isolated
in good yields and characterized by single-crystal X-ray
diffraction analyses (Figures 2 and 3). Complexes 3 and
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skii, Y. L.; Wickleder, M. S. Z. Anorg. Allg. Chem. 2004, 630, 746.
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nometallics 1997, 16, 5. Dart, J. W.; Lloyd, M. K.; McCleverty, J. A.;
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11544.

5636 Organometallics, Vol. 24, No. 23, 2005
Vicente et al.
Figure 1. Molecular structure of 2 (50% thermal el-
lipsoids). Selected bond lengths (Å) and angles (deg): Rh-
C(2) ) 1.975(2), Rh-C(3) ) 1.978(2), Rh-C(1) ) 2.066(2),
Rh-P ) 2.3605(5), Rh-S ) 2.3763(5), S-O(1) ) 1.4655-
(16), S-O(2) ) 1.4679(15), F(1)-C(1) ) 1.378(2), F(2)-C(1)
) 1.357(2), F(3)-C(1) ) 1.368(2), N(1)-C(2) ) 1.156(3),
N(2)-C(3) ) 1.157(3); C(2)-Rh-C(3) ) 168.24(8), C(2)-
Rh-C(1) ) 84.07(8), C(3)-Rh-C(1) ) 88.68(8), C(2)-Rh-P
) 93.50(6), C(3)-Rh-P ) 91.43(6), C(1)-Rh-P ) 166.68-
(6), C(2)-Rh-S ) 93.54(6), C(3)-Rh-S ) 95.86(6), C(1)-
Rh-S ) 91.24(6), P-Rh-S ) 101.996(18), O(1)-S-O(2)
) 113.19(9), O(1)-S-Rh ) 103.64(6), O(2)-S-Rh ) 104.24-
(6), C(2)-N(1)-C(11) ) 174.4(2), C(3)-N(2)-C(21) ) 176.8-
(2), F(2)-C(1)-F(3) ) 103.30(16), F(2)-C(1)-F(1) ) 103.96-
(16), F(3)-C(1)-F(1) ) 103.37(16), F(2)-C(1)-Rh )
117.16(14), F(3)-C(1)-Rh ) 117.68(14), F(1)-C(1)-Rh )
109.70(13), N(1)-C(2)-Rh ) 170.69(18), N(2)-C(3)-Rh )
174.96(18).
Figure 2. Molecular structure of 3 (50% thermal el-
lipsoids; hydrogen atoms are omitted). Selected bond
lengths (Å) and angles (deg): Rh-C(9) ) 1.974(4), Rh-
C(8) ) 1.981(4), Rh-C(1) ) 2.065(3), Rh-C(3) ) 2.122(3),
Rh-C(2) ) 2.216(3), Rh-P ) 2.3717(9), N(1)-C(4) ) 1.148-
(5), N(2)-C(5) ) 1.137(5), N(3)-C(6) ) 1.141(5), N(4)-C(7)
) 1.145(5), N(5)-C(8) ) 1.148(4), N(6)-C(9) ) 1.151(4),
F(1)-C(1) ) 1.365(4), F(2)-C(1) ) 1.365(4), F(3)-C(1) )
1.364(4), C(2)-C(4) ) 1.434(5), C(2)-C(5) ) 1.446(5), C(2)-
C(3) ) 1.509(5), C(3)-C(7) ) 1.443(5), C(3)-C(6) ) 1.448-
(5); C(9)-Rh-C(8) ) 177.02(14), C(9)-Rh-C(1) ) 87.57-
(14), C(9)-Rh-C(2) ) 92.92(13), C(8)-Rh-C(1) ) 93.59(14),
C(9)-Rh-C(3) ) 91.29(13), C(8)-Rh-C(3) ) 91.19(14),
C(8)-Rh-C(2) ) 87.89(13), C(9)-Rh-P ) 89.62(10), C(8)-
Rh-P ) 87.47(10), C(1)-Rh-P ) 100.07(10), C(8)-N(5)-
C(11) ) 175.4(3), C(9)-N(6)-C(21) ) 177.8(3), F(3)-C(1)-
F(2) ) 103.5(3), F(3)-C(1)-F(1) ) 103.6(3), F(2)-C(1)-
F(1) ) 103.3(3), F(3)-C(1)-Rh ) 115.7(2), F(2)-C(1)-Rh
) 117.6(2), F(1)-C(1)-Rh ) 111.5(2), C(4)-C(2)-C(5) )
113.0(3), C(4)-C(2)-C(3) ) 117.5(3), C(5)-C(2)-C(3) )
117.2(3), C(4)-C(2)-Rh ) 115.9(2), C(5)-C(2)-Rh ) 119.5-
(2), C(7)-C(3)-C(6) ) 113.5(3), C(7)-C(3)-C(2) ) 118.9-
(3), C(6)-C(3)-C(2) ) 116.3(3), C(7)-C(3)-Rh ) 113.8(2),
C(6)-C(3)-Rh ) 115.4(2), N(5)-C(8)-Rh ) 176.4(3),
N(6)-C(9)-Rh ) 179.2(3).
4 were not affected by the presence of an excess of olefin
or by heating at 70 °C overnight. No significant reaction
took place when complex 1 was treated with phenyl-
acetylene or bis(trimethylsilyl)acetylene at room tem-
perature. The reactions of 1 with alkynes containing
electron-withdrawing groups, such as dimethyl acety-
lenedicarboxylate, methyl propiolate, or methyl 2-phe-
nylpropiolate, gave mixtures which could not be char-
acterized.
1JRhP, 2JRhF, and 3JPF are very similar to those observed
in [Rh(CF3)(CNXy)3(PPh3)] (7),13 which suggests that
the structure of the carbonyl complex may be trigonal
bipyramidal, as for 7. An unambiguous assignment of
the minor trifluoromethyl complexes could not be car-
ried out because of their low abundances (9%, 4%, and
1%). We temptatively propose the composition [Rh(CF3)-
(CNXy)(CO)2(PPh3)] only for the most abundant of them
on the basis of their NMR data (19F, doublet of doublets;
When the reaction of complex 1 with CO was carried
out in a NMR tube, a single set of broad signals was
observed in the 19F and 31P{1H} NMR spectra at 25 °C.
When the temperature was lowered to -60 °C, the
signals became sharp and the 19F NMR spectrum
revealed the presence of four signals in the range where
Rh-CF3 groups usually appear, suggesting the presence
of a mixture of four trifluoromethyl complexes which
are in fast exchange at room temperature on the NMR
time scale. These complexes could not be isolated,
because they easily lost CO when the solvent was re-
moved under vacuum. The major component (its abun-
1
2
31P{1H}, doublet of quadruplets, with JRhP, JRhF and
3JPF values similar to those of [Rh(CF3)(CNXy)2(CO)-
(PPh3)]). The IR spectrum showed two lower intensity
bands at 2018 and 1976 cm-1, which could correspond
to ν(CO) modes of the minor components.
dance was 86%, as determined by integration of the 19
F
Complex 1 was reacted with CF3CO2H in order to test
if protonolysis of the C-F bonds would take place. Thus,
when 1 was treated with an equimolar amount of CF3-
CO2H in C6D6, the 19F NMR spectrum of the reaction
mixture showed after a few minutes a singlet at -75.2
ppm (assigned to CF3CO2-), which was the main signal.
In addition, in the range from 24.2 to -17.7 ppm, where
the Rh-CF3 groups usually appear, no less than 25
signals were observed, which could not be identified.
After 1 h, a yellow solid had crystallized out from the
reaction mixture. The 31P NMR spectrum (CDCl3) of this
NMR spectrum) gave a doublet of doublets and a doublet
of quadruplets in the 19F and 31P{1H} NMR spectra,
respectively, which are typical of the Rh(CF3)(PPh3)
1
unit. In addition, the H NMR spectrum showed two
equivalent XyNC ligands, and the IR spectrum showed
intense bands in the range where the ν(CN) (2116 and
2086 cm-1) and ν(CO) (1958 cm-1) modes of the XyNC
and CO ligands appear in similar complexes.13 These
data suggest that the main component could be [Rh-
(CF3)(CNXy)2(CO)(PPh3)]. In addition, the values of δ,

Reactivity of Rh(I) Trifluoromethyl Complexes
Organometallics, Vol. 24, No. 23, 2005 5637
Scheme 2
Figure 3. Molecular structure of 4 (50% thermal el-
lipsoids). Selected bond lengths (Å) and angles (deg): Rh-
C(1) ) 2.0654(18), Rh-C(11) ) 1.9846(18), Rh-C(21) )
2.0034(17), Rh-C(2) ) 2.1536(18), Rh-C(3) ) 2.1491(18),
Rh-P ) 2.3810(5), F(1)-C(1) ) 1.372(2), F(2)-C(1) )
1.366(2), F(3)-C(1) ) 1.378(2), C(2)-C(3) ) 1.430(3), N(1)-
C(11) ) 1.160(2), N(2)-C(21) ) 1.155(2); C(11)-Rh-C(21)
) 87.43(7), C(11)-Rh-C(1) ) 86.34(7), C(21)-Rh-C(1) )
173.76(7), C(11)-Rh-C(3) ) 107.50(7), C(21)-Rh-C(3) )
96.51(7), C(1)-Rh-C(3) ) 85.68(7), C(11)-Rh-C(2) )
146.32(7), C(21)-Rh-C(2) ) 95.37(7), C(1)-Rh-C(2) )
90.00(7), C(3)-Rh-C(2) ) 38.82(7), C(11)-Rh-P ) 105.37-
(5), C(21)-Rh-P ) 88.93(5), C(1)-Rh-P ) 92.42(5),
C(11)-N(1)-C(12) ) 165.21(17), C(21)-N(2)-C(22) )
173.73(17), F(2)-C(1)-F(1) ) 102.82(14), F(2)-C(1)-F(3)
) 102.65(14), F(1)-C(1)-F(3) ) 102.10(14), F(2)-C(1)-
Rh ) 115.91(11), F(1)-C(1)-Rh ) 117.65(12), F(3)-C(1)-
Rh ) 113.65(12), C(2)-C(3)-C(4) ) 107.39(17), C(3)-C(2)-
C(5) ) 106.79(16), C(4)-C(3)-Rh ) 112.34(12), C(5)-C(2)-
Rh ) 112.17(12).
The reactions of 1 with NOBF4 or Diazald (N-methyl-
N-nitroso-p-toluenesulfonamide) gave complex mixtures
which could not be characterized. The treatment of 1
with bases such as NH3, pyridine, and NaOMe did not
produce any significant reaction at room temperature.
When complex 1 was treated with 35% H2O2 in an
NMR tube, Ph3PO and [Rh(CF3)(CNXy)3] (6) were the
main products detected by NMR (Scheme 2), together
with 1 and other unidentified products. We have re-
ported that in d8-toluene solution, complex 1 is in
equilibrium with traces of complexes 6 and trans-[Rh-
(CF3)(CNXy)(PPh3)2] resulting from the dissociation and
recoordination of PPh3 or XyNC ligands of 1.13 There-
fore, the presence of H2O2 inhibits the formation of
trans-[Rh(CF3)(CNXy)(PPh3)2], because the dissociated
PPh3 transforms into Ph3PO and contributes to the
formation of 6.
Because [Rh(CF3)(CNXy)3(PPh3)] (7) contains three
XyNC ligands and we have shown that it is partially
dissociated in solution to give PPh3 and 6,13 the reaction
of 7 with H2O2 was carried out in order to prepare pure
6. However, formation of 6 and Ph3PO was observed,
but the yields were moderate to low and were sometimes
not reproducible.
solid showed only the presence of the cationic complex
trans-[Rh(CNXy)2(PPh3)2]+, whose identity was con-
firmed by spectroscopy as well as by an independent
synthesis of the salt trans-[Rh(CNXy)2(PPh3)2]CF3CO2
(5), which was prepared by a modification of a reported
method.20 Thus, despite the fact that all starting mate-
rial disappeared after a few minutes, the reaction is
quite complex and unselective and only complex 5 could
be identified and isolated in a low yield (18%). The 19F
NMR spectrum of the isolated yellow solid showed,
apart from the signal of CF3CO2-, two smaller signals
at -140.7 and -154.7 ppm corresponding to the anions
To find a better method for the synthesis of 6, the
26
reaction of [Rh(µ-OH)(COD)]2 with XyNC and Me3-
SiCF3 was studied (Scheme 2). Under these conditions,
complex 6 was formed as the main product together with
small amounts of other unidentified isocyanide-contain-
ing products, which could be separated by crystallization
to give pure 6 in moderate yields. It is noteworthy that,
in contrast to the previously reported synthesis of
trifluoromethyl complexes by using Me3SiCF3,12-15 the
formation of 6 took place without the need of fluoride
ions to activate this reagent.27 The stability of complex
6 is remarkable, because the Rh-CF3 group is not
significantly affected by the presence of H2O and H2O2
during its synthesis. In addition, it is air stable, in
contrast to 1 and 7, which are easily oxidized to the
peroxo Rh(III) complex [Rh(CF3)(η2-O2)(CNXy)2(PPh3)]
in contact with air.13
- 24
- 25
SiF5
and BF4
,
respectively, which are likely to
arise from the attack of the borosilicate glass of the flask
by HF generated in the reaction.24 In addition, we note
that no CF3H was detected in the reaction mixture by
1H and 19F NMR spectroscopy and that no signals of
metal-bound fluorine were observed in the high-field
region of the 19F NMR spectrum, which, as one of the
rewievers pointed out, would indicate an initial migra-
tion of fluorine to the metal. Therefore, C-F protonoly-
sis seems to take place in the reaction of 1 with
CF3CO2H to a detectable extent; however, given the
complexity of the reaction, its mechanism was not
further investigated.
When the reaction was carried out in an NMR tube
(C6D6), two new signals at 0.12 and 0.10 ppm were
(24) Gorol, M.; Mo¨sch-Zanetti, N. C.; Roesky, H. W.; Noltemeyer,
M.; Schmidt, H.-G. Eur. J. Inorg. Chem. 2004, 2678.
(25) Gandelmann, M.; Konstantinovski, L.; Rozenberg, H.; Milstein,
D. Chem. Eur. J. 2003, 9, 2595. Padelidakis, V.; Tyrra, W.; Naumann,
D. J. Fluorine Chem. 1999, 99, 9. Plakhotnik, V. N.; Ernst, L.; Sakhaii,
P.; Tovmash, N. F.; Schmutzler, R. J. Fluorine Chem. 1999, 98, 133.
(26) Uso´n, R.; Oro, L. A.; Cabeza, J. A. Inorg. Synth. 1985, 23, 126.
(27) Maggiarosa, N.; Tyrra, W.; Naumann, D.; Kirij, N. V.; Yagupol-
skii, Y. L. Angew. Chem., Int. Ed. 1999, 38, 2252. Kolomeitsev, A.;
Bissky, G.; Lork, E.; Movchun, V.; Rusanov, E.; Kirsch, P.; Ro¨schentha-
ler, G.-V. Chem. Commun. 1999, 1017. Prakash, G. K. S.; Yudin, A.
K. Chem. Rev. 1997, 97, 757.

5638 Organometallics, Vol. 24, No. 23, 2005
Vicente et al.
Scheme 3
observed in the 1H NMR spectrum which were assigned
to Me3SiOH and (Me3Si)2O. GC/MS analysis of the
reaction mixture confirmed the presence of both. For-
mation of (Me3Si)2O can be explained by condensation
of Me3SiOH with another molecule of Me3SiOH or by
reaction with Me3SiCF3, which was added in excess.
The reaction of 6 with TCNE or MA gave the penta-
coordinate complexes [Rh(CF3)(CNXy)3L] (L ) TCNE
(8), MA (9)) (Scheme 2). Although we could not grow
suitable single crystals to determine the geometry of
these complexes, their NMR spectra are compatible with
structures resulting from substitution of PPh3 by XyNC
in complexes 3 and 4, respectively. The reaction of 6
with SO2 or dimethyl acetylenedicarboxylate gave mix-
tures of products which could not be characterized.
Oxidative addition reactions with complexes 1 and 6
were studied. Unfortunately, the reactions of 1 with I2,
MeI, or n-C4F9I were not clean and the resulting
complexes could not be isolated in pure form and
characterized. In contrast, 6 reacted with MeI or n-C4F9I
to afford [Rh(CF3)(R)I(CNXy)3] (R ) Me (10), n-C4F9
(11)) (Scheme 3) in good yield. The result of the reaction
of 6 with MeI is in contrast with that of the analogous
reaction of trans-[Rh(CF3)(CO)(PPh3)2], which gives [Rh-
(CF3){C(O)Me}I(PPh3)2]. This acyl complex results from
oxidative addition of MeI, followed by CO insertion into
the Rh-Me bond.22 In our case, the insertion of XyNC
to give an iminoacyl complex did not occur. A related
result is the reaction of trans-[Ir(CF3)(CO)(PPh3)2] with
MeI to give [Ir(CF3)(Me)I(CO)(PPh3)2].28
Figure 4. Molecular structure of 12 (50% thermal el-
lipsoids). Selected bond lengths (Å) and angles (deg): Rh-
C(21) ) 1.976(5), Rh-C(11) ) 1.978(5), Rh-C(1) ) 2.075-
(5), Rh-C(2) ) 2.090(5), Rh-I#1 ) 2.7620(4), Rh-I )
2.7648(4), I-Rh#1 ) 2.7620(4), N(1)-C(11) ) 1.149(6),
N(2)-C(21) ) 1.152(6), F(1)-C(1) ) 1.341(5), F(2)-C(1) )
1.336(5), F(3)-C(1) ) 1.344(5), F(4)-C(2) ) 1.358(5), F(5)-
C(2) ) 1.382(5); C(21)-Rh-C(11) ) 173.76(18), C(21)-Rh-
C(1) ) 87.19(18), C(11)-Rh-C(1) ) 90.50(18), C(21)-Rh-
C(2) ) 97.28(18), C(11)-Rh-C(2) ) 88.54(18), C(1)-Rh-
C(2) ) 90.55(18), C(21)-Rh-I#1 ) 86.98(13), C(11)-Rh-
I#1 ) 87.37(13), C(1)-Rh-I#1 ) 93.23(12), C(2)-Rh-I#1
) 174.44(12), C(21)-Rh-I ) 92.00(13), C(11)-Rh-I )
90.10(13), C(1)-Rh-I ) 177.77(13), C(2)-Rh-I ) 91.61-
(12), I#1-Rh-I ) 84.647(13), Rh#1-I-Rh ) 95.353(13),
F(2)-C(1)-F(1) ) 106.3(4), F(2)-C(1)-F(3) ) 106.4(4),
F(1)-C(1)-F(3) ) 104.9(4), F(2)-C(1)-Rh ) 113.7(3),
F(1)-C(1)-Rh ) 111.5(3), F(3)-C(1)-Rh ) 113.3(3), F(4)-
C(2)-F(5) ) 104.9(4), F(4)-C(2)-C(3) ) 107.2(4), F(5)-
C(2)-C(3) ) 106.2(4), F(4)-C(2)-Rh ) 112.0(3), F(5)-
C(2)-Rh ) 108.0(3), C(3)-C(2)-Rh ) 117.7(3).
each other (see Spectroscopic Characterization). The
attempts to grow single crystals of 11 by liquid diffusion
were unsuccessful; however, by slow evaporation of a
CDCl3 solution of 11 in an NMR tube, single crystals
grew after several days, which were used for an X-ray
diffraction analysis. Surprisingly, the determined struc-
ture was that of the dinuclear complex [{Rh(CF3)(n-
C4F9)(CNXy)2}2(µ-I)2] (12) (Figure 4 and Scheme 3)
instead of that of complex 11. The formation of 12 from
11 may be explained by dissociation of one XyNC ligand
followed by dimerization through iodo bridging. How-
ever, all our attempts to synthesize 12 were unsuccess-
Both 10 and 11 were characterized by spectroscopy
as well as by elemental analysis. In addition, an X-ray
diffraction analysis was carried out on single crystals
of 10. Despite the fact that the structural model could
be crudely refined and its qualitative nature unambigu-
ously established, iodine atom disorder over the two
mutually trans sites precluded satisfactory refinement.
The observed arrangement of the ligands around the
metal is as shown in Scheme 3, with the XyNC ligands
in a mer disposition and the Me and I ligands placed
mutually in trans positions. This configuration results
after a trans addition of MeI to complex 6. The 1H NMR
spectra of 10 and 11 agree with the mer disposition of
the XyNC ligands observed in the crystal structure of
10. In addition, the presence of the Rh-Me bond was
1
ful. Thus, the H and 19F NMR spectra of 11 in CDCl3
solution do not change significantly after 6 days at room
temperature, and on heating the solution to 60 °C for
75 min a mixture of products was formed. Treatment
of 11 with [AuCl(SMe2)] in order to remove a XyNC
ligand by formation of [AuCl(CNXy)] did not give
complex 12. Assuming that the relative disposition of
the ligands in 11 is not altered during the formation of
12, the crystal structure of the latter suggests that in
complex 11 the CF3 and n-C4F9 groups are disposed cis
to each other; however, it does not establish whether
in 11 the iodo ligand is placed trans to the CF3 or to
the n-C4F9 group and, thus, if the oxidative addition
occurred in a cis or trans fashion.
1
confirmed by H and 13C{1H} NMR spectroscopy (see
Spectroscopic Characterization). The 19F NMR spectrum
of 11 showed the presence of the Rh-bound CF3 and
n-C4F9 groups, which were coupled with 103Rh and with
(28) Brothers, P. J.; Burrell, A. K.; Clark, G. R.; Rickard, C. E. F.;
Roper, W. R. J. Organomet. Chem. 1990, 394, 615.

Reactivity of Rh(I) Trifluoromethyl Complexes
Organometallics, Vol. 24, No. 23, 2005 5639
Table 1. Selected NMR Data of the New Complexesa
compd
δ(19F) (ppm)
δ(31P) (ppm)
1JRhP (Hz)
2JRhF (Hz)
3JPF (Hz)
[Rh(CF3)(CNXy)2(PPh3)(η1-SO2)] (2)
[Rh(CF3)(CNXy)2(PPh3)(η2-TCNE)] (3)
[Rh(CF3)(CNXy)2(PPh3)(η2-MA)] (4)
trans-[Rh(CNXy)2(PPh3)2]CF3CO2 (5)
[Rh(CF3)(CNXy)3] (6)
-9.5 dd
3.6 d
2.45 dq
28.5 d
28.9 dq
31.0 d
92.1
99.8
127.5
122.9
19.8
14.4
10.2
50.6
c
21.2
-11.6 dd
-74.9 s
-9.6 d
24.3
14.2
9.3
15.8
13.6
[Rh(CF3)(CNXy)3(η2-TCNE)] (8)
[Rh(CF3)(CNXy)3(η2-MA)] (9)
1.7 d
-11.9 d
-11.2 d
-8.1 dttb
[Rh(CF3)(Me)I(CNXy)3] (10)
[Rh(CF3)(n-C4F9)I(CNXy)3] (11)
a Legend: s ) singlet, d ) doublet, t ) triplet, q ) quadruplet. b Rh-CF3. c The 31P-19F coupling was not observed.
Spectroscopic Characterization. Complexes 2, 3,
to the Rh-CF2 distances reported in Rh(III) pentafluo-
roethyl or heptafluoropropyl complexes (2.052-2.086
Å).16,17,19,31 The mean C-F distance observed in the CF3
group of 12 (1.340 Å) is shorter than that of the CF2
group (1.37 Å), which is in the range of mean C-F
distances reported in the R-CF2 groups of Rh(III) pen-
tafluoroethyl or heptafluoropropyl complexes (1.34-
1.395 Å). As has been noted previously,13,17 the mean
Rh-C-F angles in complexes 2-4 and 12 (2, 114.85°;
3, 114.93°; 4, 115.74°; 12, 112.8° (CF3) and 110.0° (R-
CF2)) are larger and the F-C-F angles (2, 103.54°; 3,
103.47°; 4, 102.52°; 12, 105.9° (CF3) and 104.9° (R-CF2))
are smaller than the ideal tetrahedral angle, in agree-
ment with the VSEPR model.
The geometry of complex 2 is pseudo square pyrami-
dal. The SO2 ligand is placed in the apical position, and
the isocyanide ligands are disposed trans to each other.
The C(1)-Rh-P and C(2)-Rh-C(3) angles are 166.68-
(6) and 168.24(8)°, respectively, and the angles between
the sulfur atom and the Rh-bonded carbon and phos-
phorus atoms are in the range 91.24(6)-101.996(18)°.
The SO2 ligand is η1 coordinated through the sulfur
atom and has a pyramidal geometry. The Rh-S and
S-O distances (Rh-S, 2.3763(5) Å; S-O, 1.4655(16) and
1.4679(15) Å) and the O-S-Rh and O-S-O angles (O-
S-Rh, 103.64(6) and 104.24(6)°; O-S-O, 113.19(9)°) fall
in the range of values reported for Rh(I) complexes
containing a pyramidal SO2 ligand coordinated through
the S atom.32 The S-O bonds of the SO2 ligand are bent
away from the CF3 group and toward the PPh3 and an
XyNC ligand.
Complex 3 possess a distorted-trigonal-bipyramidal
geometry, with the isocyanide ligands placed in axial
positions (C(8)-Rh-C(9), 177.02(14)°). Concerning the
equatorial ligands, the CF3-Rh-P angle is 100.07(10)°,
and the C′-Rh-P and C′-Rh-CF3 (C′ is the centroid
of the TCNE olefinic carbons) angles are 138.60 and
121.41°, respectively. The olefinic carbons of the TCNE
ligand are approximately coplanar with Rh, the CF3
carbon, and the phosphorus atoms. As expected, the
TCNE ligand is significantly distorted from planarity
(the distances between the average plane of C(4), C(5),
C(6), and C(7) carbon atoms and the olefinic carbons
C(2) and C(3) are 0.437 and 0.428 Å, respectively). The
Rh-C (2.122(3) and 2.216(3) Å) and CdC (1.509(5) Å)
distances are comparable to the previously reported
1
and 5 show in their H NMR spectra a singlet corre-
sponding to the Me groups of the equivalent XyNC
ligands, while complex 4 showed two singlets corre-
sponding to the axial and equatorial XyNC ligands. This
is in agreement with its crystal structure and suggests
that the solid-state structure is not altered in solution.
Complexes 6-8 and 11 show two Me singlets in their
1H NMR spectra of 2:1 intensity ratio, which suggest
that two XyNC ligands are in a trans disposition. The
Rh-Me group of complex 10 appears in the 13C{1H}
NMR spectrum as a doublet of quadruplets at -8.1 ppm
(1JRhC ) 20.6 Hz and 3JCF ) 5.5 Hz) and in the 1H NMR
2
spectrum as a doublet at 1.41 ppm, with JRhH ) 3.3
Hz.
The 19F NMR spectra of complexes 2 and 4 show
doublets of doublets by coupling with 103Rh and 31P
(Table 1), and their 31P{1H} NMR spectra show doublets
of quadruplets, as expected. The 19F and 31P{1H} NMR
spectra of complex 3 show a doublet which is not split
or broadened by lowering the temperature to -64 °C,
suggesting that 3JPF is very small. Complexes 6-8 and
11 show a doublet in their 19F NMR spectra, and 11
shows five multiplets, which were assigned by means
of a 19F,19F-COSY measurement. The Rh-CF3 group
appears as a doublet of triplets of triplets by coupling
with 103Rh and the R- and â-CF2 groups; the latter
groups give three complex multiplets, and the terminal
CF3 gives a triplet of triplets.
In the IR spectra, the ν(CtN) bands of the XyNC and
TCNE ligands appear in the ranges 2102-2204 and
2204-2218 cm-1, respectively. The MA ligand in com-
plexes 4 and 9 gives two ν(CdO) bands at 1808 and 1746
cm-1. The ν(SdO) and ν(C-F) bands could not be
assigned because of the presence of intense bands in the
expected regions belonging to other ligands.
Crystallographic Studies. The molecular struc-
tures of complexes 2-4 and 12 have been determined
by single-crystal X-ray diffraction studies. In compounds
2-4 the Rh-CF3 bond distances (2, 2.066(2) Å; 3, 2.065-
(3) Å; 4, 2.0654(18) Å) and the mean C-F distances (2,
1.368 Å; 3, 1.365 Å; 4, 1.372 Å) are similar to those
previously reported for Rh(I) trifluoromethyl complexes
(Rh-CF3, 2.051-2.112 Å; C-F, 1.369-1.381 Å).13 The
mean C-F distances are longer than those observed in
compounds containing CF3 groups bonded to nonmetal-
lic atoms (1.32229 and 1.3330 Å). In complex 12, the Rh-
CF2 distance (2.090(5) Å) is not significantly different
from the Rh-CF3 distance (2.075(5) Å), and it is close
(31) Churchill, M. R. Inorg. Chem. 1965, 4, 1734. Hughes, R. P.;
Kovacik, I.; Lindner, D. C.; Smith, J. M.; Willemsen, S.; Zhang, D.;
Guzei, I. A.; Rheingold, A. L. Organometallics 2001, 20, 3190.
(32) Kubas, G. J.; Ryan, R. R. Inorg. Chim. Acta 1981, 47, 131.
Lindner, E.; Keppeler, B.; Fawzi, R.; Steinmann, M. Chem. Ber. 1996,
129, 1103. Muir, K. W.; Ibers, J. A. Inorg. Chem. 1969, 8, 1921. Eller,
P. G.; Ryan, R. R. Inorg. Chem. 1980, 19, 142. Doux, M.; Me´zailles,
N.; Ricard, L.; Le Floch, P. Organometallics 2003, 22, 4624.
(29) Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen,
A. G.; Taylor, R. J. Chem. Soc., Perkin Trans. 2 1987, S1.
(30) Yokozeki, A.; Bauer, S. H. Top. Curr. Chem. 1973, 53, 71.

5640 Organometallics, Vol. 24, No. 23, 2005
Vicente et al.
values for Rh(I) TCNE complexes.33 The CdC bond
distance is considerably larger than in the free ligand
(1.355(2) Å)34 and is in the range of single C-C bond
distances.29
In complex 4, the geometry around the metal is
distorted trigonal bipyramidal. In contrast to 2 and 3,
where the isocyanide ligands are mutually trans, in
complex 4 an isocyanide and the CF3 ligand are placed
in axial positions (C-Rh-C, 173.76(7)°). The angles
between the metal atom and the axial and equatorial
donor atoms are close to 90° (85.68(7)-96.51(7)°). The
rhodium atom, the olefinic and CF3 carbons, and the
phosphorus atom are roughly coplanar, and the bond
angles in the equatorial plane are 105.37(5)° (P-Rh-
CN) and 126.93 and 127.56° (C′-Rh-CN and C′-Rh-
P, where C′ is the centroid of the MA olefinic carbons).
The maleic anhydride ligand is oriented toward the
isocyanide, probably in order to reduce the steric repul-
sion with the CF3 group fluorine atoms. The distance
between the olefinic carbons (1.430(3) Å) is significantly
longer than in the free molecule (1.332 Å).35 According
to a Cambridge Structural Database search,36 this is the
first crystal structure determination on a Rh complex
with MA. The Rh-C(alkene) distances (2.1536(18) and
2.1491(18) Å) are slightly longer than the values found
in 3 and are within the range of Rh-C distances found
in Rh(I) complexes with MeO2CCHdCHCO2Me (2.092-
2.193 Å).37 The CdC distance is within the range of
distances reported in transition-metal MA complexes
(1.396-1.514 Å).36
In complex 12, both metal centers are equivalent and
show a distorted-octahedral coordination, with the iso-
cyanide ligands in a mutually trans disposition. The
phenyl rings of the isocyanide ligands bonded to differ-
ent Rh atoms of the same molecule are nearly parallel
(the angle between the mean planes defined by the rings
is 5.8°) and the Rh-CtN-Xy chains are bent,38 giving
rise to a parallel offset disposition of the rings (Figure
5), which probably is adopted in order to minimize steric
repulsion and favor stabilizing interactions between the
π-electron densities.39 The distance between the cen-
troids of the phenyl rings is 3.978 Å, and the angles
between the vector defined by the centroids of the rings
and the mean planes of the rings are 64.6 and 64.3°.
The Rh-I distances (2.7620(4) and 2.7648(4) Å) are
similar to the values reported in Rh(III) containing
µ-iodo ligands.40
Figure 5. Drawing of the structure of 12 down the Rh-
Rh axis, showing the arrangement of the phenyl rings.
Conclusions
The reactivities of the square-planar trifluoromethyl
Rh(I) complexes trans-[Rh(CF3)(CNXy)2(PPh3)] (1) and
[Rh(CF3)(CNXy)3] (6) have been studied. They react
with SO2, TCNE, or MA to give formally Rh(I) penta-
coordinate adducts which are the first examples of Rh-
(I) perfluoroalkyl complexes containing SO2, TCNE, and
MA ligands. No CO, isocyanide, or olefin insertion reac-
tions into the Rh-CF3 bond have been observed. This
lack of reactivity toward insertion of unsaturated mol-
ecules is in line with the reported behavior of transition-
metal trifluoromethyl complexes, which has been attri-
buted to thermodynamic and kinetic factors.5-8 Complex
6 has been prepared by a fluoride-free method using the
reaction of [Rh(µ-OH)(COD)]2 with XyNC and Me3SiCF3.
Given that the hydroxo complex is easily available, this
method could be a simpler way to prepare Rh(I) per-
fluoroalkyl complexes starting from the desired Me3SiRF
reagent. Work on the synthesis of new Rh(I) perfluoro-
alkyl complexes by this method is currently in progress.
The reactions of 6 with MeI or n-C4F9I gave the octa-
hedral complexes [Rh(CF3)(R)I(CNXy)3] (R ) Me, n-C4F9)
resulting from oxidative addition reactions, the latter
being a rare example of a Rh(III) complex containing
two perfluoroalkyl ligands. We are currently working
on the synthesis of new Rh(III) complexes containing
different RF groups and on the study of their reactivity.
Experimental Section
General Considerations. The preparation of compounds
1,13 7,13 trans-[RhCl(CO)(PPh3)2],41 and [Rh(µ-OH)(COD)]2
26
was carried out as previously described. SO2 was produced by
dropwise addition of H2SO4 (98%) to anhydrous Na2SO3 in a
previously deoxygenated system and dried through a CaCl2
tube. Other reagents were obtained from commercial sources
and used without further purification: Me3SiCF3, 2,6-dimeth-
ylphenyl isocyanide (XyNC), and maleic anhydride (MA) from
Fluka, tetracyanoethylene (TCNE) and n-C4F9I from Aldrich,
and MeI from Panreac. All manipulations were carried out
under an inert atmosphere of nitrogen by using standard
Schlenk techniques. THF, toluene, and Et2O were distilled over
sodium-benzophenone, n-hexane and CDCl3 were passed
through a basic alumina column and deoxygenated, and
n-pentane, CH2Cl2, and C6D6 were distilled over CaH2. All
solvents were stored under nitrogen over 4 Å molecular sieves.
Infrared spectra were recorded in the range 4000-200 cm-1
on a Perkin-Elmer 16F PC FT-IR spectrometer with Nujol
(33) Bruce, M. I.; Ellis, B. G.; Skelton, B. W.; White, A. H. J.
Organomet. Chem. 2000, 607, 137. Bruce, M. I.; Hambley, T. W.; Snow,
M. R.; Swincer, G. J. Organomet. Chem. 1982, 235, 105.
(34) Becker, P.; Coppens, P.; Ross, F. K. J. Am. Chem. Soc. 1973,
95, 7604.
(35) Lutz, M. Acta Crystallogr., Sect. E 2001, 57, o1136.
(36) Cambridge Structural Database, version 5.26, May 2005.
(37) Yoshida, T.; Okano, T.; Otsuka, S.; Miura, I.; Kubota, T.;
Kafuku, K.; Nakatsu, K. Inorg. Chim. Acta 1985, 100, 7. Bianchini,
C.; Meli, A.; Peruzzini, M.; Vizza, F. Organometallics 1990, 9, 2283.
Mantovani, L.; Ceccon, A.; Gambaro, A.; Santi, S.; Ganis, P.; Venzo,
A. Organometallics 1997, 16, 2682.
(38) The torsion angles between the vectors defined by Rh and the
para carbon of the CNXy ligands are 17.4°.
(39) Hunter, C. A.; Lawson, K. R.; Perkins, J.; Urch, C. J. J. Chem.
Soc., Perkin Trans. 2 2001, 651. Magistrato, A.; Pregosin, P. S.;
Albinati, A.; Rothlisberger, U. Organometallics 2001, 20, 4178.
(40) Adamson, G. W.; Daly, J. J.; Forster, D. J. Organomet. Chem.
1974, 71, C17. Rizkallah, P. J.; Maginn, S. J.; Harding, M. M. Acta
Crystallogr., Sect. B 1990, 46, 193. Moloy, K. G.; Petersen, J. L.
Organometallics 1995, 14, 2931. Dilworth, J. R.; Morales, D.; Zheng,
Y. F. Dalton Trans. 2000, 3007. Thomas, C. M.; Neels, A.; Staeckli-
Evans, H.; Suss-Fink, G. Eur. J. Inorg. Chem. 2001, 3005.
(41) Evans, D.; Osborn, J. A.; Wilkinson, G. Inorg. Synth. 1968, 11,
99.

Reactivity of Rh(I) Trifluoromethyl Complexes
Organometallics, Vol. 24, No. 23, 2005 5641
mulls between polyethylene sheets. C, H, N, S analyses were
carried out with Carlo Erba 1108 and LECO CHS-932 mi-
croanalyzers. NMR spectra were measured on Bruker Avance
200, 300, and 400 instruments. 1H chemical shifts were
referenced to residual C6D5H (7.15 ppm), C6D5-CD2H (2.09
ppm), CHDCl2 (5.29 ppm), or CHCl3 (7.26 ppm). 13C{1H}
spectra were referenced to C6D6 (128.0 ppm), CDCl3 (77.1 ppm),
or external (CD3)2SO (40.4 ppm). 19F NMR spectra were
referenced to external CFCl3 (0 ppm). 31P{1H} NMR spectra
were referenced externally to H3PO4 (0 ppm). In cases where
13C, 19F, or 31P{1H} NMR spectra were measured in nondeu-
terated solvent, an external CD3SOCD3 capillary was used for
evaporated to dryness. Et2O (5 mL) was added to precipitate
an oil, which was converted into a yellow solid by stirring for
15 min at 0 °C. The mother liquor was removed, and the solid
was washed with Et2O (2 × 3 mL) and dried under vacuum.
Yield: 79 mg, 51%. Mp: 168-171 °C dec. Anal. Calcd for
C41H35F3N2O3PRh: C, 61.97; H, 4.44; N, 3.35. Found: C, 62.09;
H, 4.51; N, 3.58. IR (Nujol, cm-1): ν(CtN) 2164 (s), 2136 (s),
ν(CdO) 1808 (s), 1746 (s). 1H NMR (300.1 MHz, C6D6): δ 7.87
(m, 6 H, H2, Ph), 6.99 (m, 6 H, H3, Ph), 6.88 (m, 3 H, H4, Ph),
6.76-6.37 (two AB2 m, 6 H, Xy), 4.79 (m, 1 H, CHdCH), 4.23
(m, 1 H, CHdCH), 2.25 (s, 6 H, Me), 1.91 (s, 6 H, Me). 13C-
{1H} NMR (75.5 MHz, CDCl3): δ 176.0 (CdO), 175.4 (CdO),
155.5 (CtN), 152.7 (CtN), 135.5 (C2, Xy), 134.4 (C2, Xy), 134.7
(d, 1JPC ) 37.3 Hz, C1, Ph), 133.7 (d, JPC ) 11.5 Hz, Ph), 129.9
(s, C4, Ph), 129.2 (both C4, Xy), 128.3 (d, JPC ) 9.7 Hz, Ph),
128.1 (C3, Xy), 127.7 (C3, Xy), 127.5 (C1, Xy), 126.4 (C1, Xy),
locking and referencing. Abreviations used: vt ) virtual
1
triplet; br ) broad; sh ) shoulder; N ) JPC
+
3JPC. The
temperature values in NMR experiments were not corrected.
Melting points were determined on a Reichert apparatus under
an air atmosphere.
1
44.4 (dm, JRhC ) 31.5 Hz, CdC), 42.4 (m, CdC), 18.9 (Me),
18.5 (Me); the signal of CF3 carbon was not observed. 19F NMR
(282.4 MHz, C6D6): δ -11.6 (dd, 3JPF ) 21.2 Hz, 2JRhF ) 10.2
Hz). 31P{1H} NMR (121.5 MHz, C6D6): δ 28.9 (dq, 1JRhP ) 127.5
[Rh(CF3)(CNXy)2(PPh3)(η1-SO2)] (2). A solution of [RhF-
(COD)(PPh3)] (106 mg, 0.22 mmol) in THF (5 mL) was treated
with Me3SiCF3 (0.20 mL of a 2.0 M solution in THF, 0.40
mmol) at room temperature. After 5 min of stirring, XyNC (57
mg, 0.43 mmol) was added and the mixture was stirred for 1
h and evaporated to dryness under vacuum. The residue
(complex 1) was dissolved in THF (5 mL), and a stream of SO2
was bubbled through the solution for 1 min. When the bubbling
was stopped, the tube containing the reaction mixture was
sealed and the solution was stirred for 30 min. The resulting
solution was evaporated to dryness and, by addition of n-
pentane (5 mL), a yellow greenish solid precipitated. The
mother liquor was removed, and the solid was washed with
n-pentane (2 × 5 mL) and dried under vacuum. Yield: 149
mg, 91%. Mp: 113 °C dec. Anal. Calcd for C37H33N2F3O2-
PRhS: C, 58.43; H, 4.37; N, 3.68; S, 4.22. Found: C, 58.37; H,
3
Hz, JPF ) 20.7 Hz).
Reaction of 1 with CO. A solution of 1 (15 mg, 0.022
mmol) in d8-toluene (0.5 mL) was placed into an NMR tube
sealed with a septum cap. Then, a stream of CO was bubbled
through the solution by means of a needle for 1 min. The color
of the solution changed from yellow-orange to yellow. The
spectroscopic data for the obtained solution are as follows. IR
(CH2Cl2, cm-1): ν(CtN) 2116, 2086 (s, [Rh(CF3)(CNXy)2(CO)-
(PPh3)]), ν(CO) 2018 (m), 1976 (sh), 1958 (s, [Rh(CF3)(CNXy)2-
(CO)(PPh3)]). 1H NMR (200.1 MHz, d8-toluene): 25 °C, δ 7.68
(m, 6 H, H2, Ph), 6.97 (m, 9 H, H3 and H4, Ph), 6.76-6.58
(AB2 m, 6 H, Xy), 2.01 (s, 12 H, Me). 19F NMR (188.3 MHz,
d8-toluene): 25 °C, δ 3.9 (br s); -60 °C, δ 6.8 (dd, relative
1
3
2
4.61; N, 3.86; S, 4.12. IR (Nujol, cm-1): ν(CtN) 2151 (s). H
intensity ) 9%, JPF ) 61.1 Hz, JRhF ) 7.6 Hz, [Rh(CF3)-
3
NMR (300.1 MHz, C6D6): δ 7.87 (m, 6 H, H2, Ph), 6.91 (m, 9
H, H3 and H4, Ph), 6.66-6.46 (AB2 m, 6 H, Xy), 2.00 (s, 12 H,
Me). 13C{1H} NMR (50.3 MHz, CDCl3): δ 136.0 (C2, Xy), 134.0
(d, JPC ) 12.1 Hz, Ph), 133.2 (d, 1JPC ) 41.3 Hz, C1, Ph), 130.6
(C4, Ph), 129.3 (C4, Xy), 128.7 (d, JPC ) 10.0 Hz, Ph), 127.8
(C3, Xy), 126.5 (C1, Xy), 18.2 (Me); the signals of CF3 and Ct
N carbons were not observed. 19F NMR (282.4 MHz, C6D6): δ
-9.5 (dd, 3JPF ) 50.6 Hz, 2JRhF ) 19.8 Hz). 31P{1H} NMR (121.5
(CNXy)(CO)2(PPh3)]), 5.7 (dd, relative intensity 86%, JPF
)
61.0 Hz, 2JRhF ) 8.0 Hz, [Rh(CF3)(CNXy)2(CO)(PPh3)]), 4.7 (dd,
3
2
relative intensity 4%, JPF ) 60.8 Hz, JRhF ) 8.0 Hz), 3.9 (d,
relative intensity 1%, 2JRhF ) 9.1 Hz). 31P{1H} NMR (81.0 MHz,
d8-toluene): 25 °C, δ 35.5 (br s); -60 °C (162.3 MHz, d8-
toluene), δ 40.9 (dq, 1JRhP ) 74.9 Hz, 3JPF ) 60.9 Hz, [Rh(CF3)-
(CNXy)2(CO)(PPh3)]), 36.4 (dq, JRhP ) 71.9 Hz, JPF ) 60.8
Hz, [Rh(CF3)(CNXy)(CO)2(PPh3)]).
1
3
1
3
MHz, C6D6): δ 24.5 (dq, JRhP ) 92.1 Hz, JPF ) 50.4 Hz).
[Rh(CF3)(CNXy)2(PPh3)(η2-TCNE)] (3). A solution of 1 in
THF (5 mL) was prepared as for 2 from [RhF(COD)(PPh3)]
(77 mg, 0.16 mmol), Me3SiCF3 (0.32 mmol), and XyNC (43 mg,
0.33 mmol). TCNE (21 mg, 0.16 mmol) was added to this
solution to give a green solution which turned brown in about
5 min. After it was stirred for 30 min, it was evaporated to
dryness and Et2O (5 mL) was added to give a beige precipitate.
The mother liquor was removed, and the solid was washed
with Et2O (2 × 5 mL) and dried under vacuum. Yield: 121
mg, 94%. Mp: 154 °C. Anal. Calcd for C41H35N2F3O3PRh: C,
62.63; H, 4.03; N, 10.19. Found: C, 62.40; H, 3.93; N, 9.90. IR
(Nujol, cm-1): ν(CtN, XyNC) 2188 (s), ν(CtN, TCNE) 2218
(m), 2212, 2204 (m). 1H NMR (300.1 MHz, CDCl3): δ 7.58 (m,
6 H, H2, Ph), 7.46-7.36 (m, 9 H, H3 and H4, Ph), 7.20-6.98
(AB2 m, 6 H, Xy), 2.11 (s, 12 H, Me). 13C{1H} NMR (100.8 MHz,
CDCl3): δ 137.3 (C2, Xy), 133.5 (d, JPC ) 11.1 Hz, Ph), 131.5
Reaction of 1 with CF3CO2H. A solution of 1 (17 mg, 0.024
mmol) in C6D6 (0.5 mL) was treated with CF3CO2H (2 µL, 0.026
mmol). After 10 min, the NMR spectrum of the resulting
solution showed a complex mixture of compounds. After 30
min, a yellow solid started to precipitate in the NMR tube,
and 1 h later, the solution was removed and the solid washed
with Et2O (1 mL) and dried under vacuum. Larger amounts
of the yellow solid were obtained in the following way:
a
solution of 1 was prepared as for 2 from [RhF(COD)(PPh3)]
(147 mg, 0.30 mmol), Me3SiCF3 (0.6 mmol), and XyNC (79 mg,
0.60 mmol) in THF (5 mL). The volatiles were removed in
vacuo, the residue was disolved in toluene (3 mL), and CF3-
CO2H (23 µL, 0.31 mmol) was added. The solution was stirred
for a few seconds and stored for 4 h without stirring. A yellow
microcrystalline solid precipitated, which was filtered, washed
with n-pentane (3 × 5 mL), and dried in vacuo. Yield: 55 mg,
18% (calcd as trifluoroacetate). IR (Nujol): ν(CtN) 2126 (s),
1
1
(d, JPC ) 3.0 Hz, C4, Ph), 130.9 (d, JPC ) 45.0 Hz, C1, Ph),
ν(CdO) 1696 (m). The H and 31P NMR spectra of this solid
130.5 (C4, Xy), 129.0 (d, JPC ) 11.1 Hz, Ph), 128.1 (C3, Xy),
125.2 (C1, Xy), 117.6, 116.6, 116.5 (three s, C-CN), 18.3 (s,
Me); the signals of CF3, Rh-CN, and CdC carbons were not
observed. 19F NMR (282.4 MHz, CDCl3): δ 3.6 (d, 3JRhF ) 14.4
Hz). 31P{1H} NMR (121.5 MHz, CDCl3): δ 28.5 (d, 1JRhP ) 99.8
Hz).
were identical with those of complex 5 (see below). 19F NMR
(282.4 MHz, CDCl3): δ -75.9 (s, CF3CO2-), -140.7 (s, SiF5-),
-154.68 (br s, 10BF4-), -154.73 (br s, 11BF4-). MS (+FAB): m/z
889 ([Rh(CNXy)2(PPh3)2]+), 758 ([Rh(CNXy)(PPh3)2]+), 627
([Rh(CNXy)2(PPh3)]+), 496 ([Rh(CNXy)(PPh3)]+). MS (-ESI):
m/z 123 (SiF5-), 113 (CF3CO2-), 87 (BF4-), 69 (CF3-).
[Rh(CF3)(CNXy)2(PPh3)(η2-MA)] (4). A solution of 1 in
THF (5 mL) was prepared as for 2 from [RhF(COD)(PPh3)]
(96 mg, 0.19 mmol), Me3SiCF3 (0.40 mmol), and XyNC (52 mg,
0.40 mmol). Maleic anhydride (22 mg, 0.22 mmol) was added
to give an orange solution, which was stirred for 1 h and then
trans-[Rh(CNXy)2(PPh3)2]CF3CO2 (5). Complex 5 was
prepared by a modification of the procedure reported by Dart
and co-workers.20 A suspension of trans-[RhCl(CO)(PPh3)2]
(140 mg, 0.20 mmol) in CH2Cl2/MeOH (1:1, 30 mL) was treated
with XyNC (53 mg, 0.40 mmol) and NaCF3CO2 (28 mg, 0.21

5642 Organometallics, Vol. 24, No. 23, 2005
Table 2. Crystal Data for Complexes 2-4 and 12
Vicente et al.
2
3
4
12
formula
Mr
cryst size (mm)
cryst syst
space group
cell constants
a, Å
b, Å
c, Å
R, deg
â, deg
C
37H33F3N2O2PRhS
C44H35Cl2F3N6PRh
909.56
C47H35D6F3N2O3PRh
878.70
C48H38Cl6F24I2N4Rh2
1799.14
760.59
0.36 × 0.29 × 0.18
monoclinic
P21/n
0.26 × 0.14 × 0.14
0.35 × 0.32 × 0.20
0.33 × 0.12 × 0.10
monoclinic
triclinic
monoclinic
P21/c
P1h
C2/c
11.9599(6)
18.4790(9)
15.7470(7)
90
92.871(2)
90
18.6130(8)
10.1753(4)
21.6122(11)
90
95.826(2)
90
9.4633(4)
29.9171(14)
16.2557(7)
12.9824(6)
90
95.397(2)
90
14.5730(6)
14.9666(6)
86.404(2)
83.216(2)
81.008(2)
γ, deg
V, Å3; Z
λ, Å
3475.8(3); 4
4072.1(3); 4
2022.32(14); 2
6285.7(5); 4
0.710 73
F(calcd), Mg m-3
F(000)
)
1.453
1552
1.484
1848
1.443
896
1.901
3472
T, K
100(2)
0.649
100(2)
0.644
100(2)
0.520
100(2)
1.871
µ (mm-1
)
transmissns
θ range, deg
limiting indices
0.8922 and 0.8000
1.70-26.37
-14 e h e 14
-23 e k e 23
-19 e l e 19
0.9152 and 0.8504
1.89-26.37
-23 e h e 23
-12 e k e 12
-27 e l e 27
0.9032 and 0.8390
1.93-28.17
-12 e h e 12
-18 e k e 18
-19 e l e 18
0.8350 and 0.5772
2.08-26.37
-37 e h e 37
-20 e k e 20
-16 e l e 16
no. of rflns
measd
indep
37 871
7106
0.029
44 003
8303
0.0615
23 736
9081
0.0201
34 138
6429
0.0213
Rint
abs cor
refinement method
semiempirical from equivalents
full-matrix least-squares on F2
no. of data/restraints/params
7106/40/431
1.157
0.0294
0.0709
0.572
8303/40/518
1.103
0.0490
0.1147
1.296
9081/48/518
1.084
0.0290
0.0724
0.568
6429/21/386
1.030
0.0443
0.1069
2.157
S(F2)
R1a
wR2b
largest diff peak, e Å-3
max ∆r, e Å-3
-0.263
-0.823
-0.618
-2.109
2
2
a R1 ) ∑||Fo| - |Fc||/∑|Fo| for reflections with I > 2σ(I). b wR2 ) [∑[w(Fo - Fc )2]/∑[w(Fo2)2]0.5 for all reflections; w-1 ) σ2(F2) + (aP)2
2
+ bP, where P ) (2Fc + Fo2)/3 and a and b are constants set by the program.
mmol). The mixture was stirred for 30 min and evaporated to
dryness under vacuum, and the residue was extracted with
CH2Cl2 (5 mL). The yellow extract was filtered and concen-
trated up to ca. 0.5 mL, and Et2O (5 mL) was added to
precipitate a yellow solid. The solution was removed, and the
solid was washed with Et2O (2 × 5 mL) and dried under
vacuum. Yield: 130 mg, 65%. Mp: 153-156 °C dec. Anal.
Calcd for C56H48N2F3O2P2Rh: C, 67.07; H, 4.82; N, 2.79.
Found: C, 66.89; H, 4.88; N, 2.65. IR (Nujol, cm-1): ν(CtN)
Method B. Solid [Rh(µ-OH)(COD)]2 (100 mg, 0.22 mmol)
was added in small portions for a period of 3 min to a solution
of XyNC (179 mg, 1.36 mmol) and Me3SiCF3 (0.6 mL of a 2.3
M THF solution, 1.38 mmol) in THF (7 mL). The brown
solution was stirred for 15 min and concentrated under
vacuum to about 1 mL; Et2O (5 mL) was added, and the flask
was stored at -30 °C overnight. A yellow microcrystalline solid
formed. The mother liquor was removed, and the solid was
washed with cold Et2O (-20 °C, 3 × 3 mL) and dried under
vacuum. Yield: 140 mg, 56%. Mp: 149-152 °C dec. Anal.
Calcd for C28H27N3F3Rh: C, 59.48; H, 4.81; N, 7.43. Found:
C, 59.33; H, 4.67; N, 7.33. IR (Nujol, cm-1): ν(CtN) 2118 (s),
1
2132 (s), ν(CdO) 1696 (m). H NMR (200.1 MHz, CDCl3): δ
7.65 (m, 12 H, H2, Ph), 7.34 (m, 18 H, H3 and H4, Ph), 7.07-
6.82 (AB2 m, 6 H, Xy), 1.62 (s, 12 H, Me). 13C{1H} NMR (100.8
2
1
MHz, CDCl3): δ 161.0 (q, JFC ) 34.6 Hz, CO2CF3), 156.1 (br
2102 (s). H NMR (300.1 MHz, C6D6): δ 6.80-6.55 (two AB2
1
d, JRhC ) 52 Hz, Rh-CN), 134.1 (s, Xy), 133.7 (vt, N ) 12.5
m, 9 H, Xy), 2.22 (s, 12 H, Me), 2.14 (s, 6 H, Me). 13C{1H} NMR
(50.3 MHz, THF/CD3SOCD3(ext)): δ 135.5 (C2, 2 Xy), 134.7
(C2, Xy), 128.7 (CH, Xy), 128.2 (CH, Xy), 128.13 (CH, Xy),
128.08 (CH, Xy), 18.4 (Me, Xy), 18.2 (Me, 2 Xy); the signals of
CF3, C1 of Xy, and CtN carbons were not observed. 19F NMR
Hz, C2, Ph), 132.6 (vt, N ) 46.4 Hz, C1, Ph), 131.0 (s, C4, Ph),
128.9 (s, Xy), 128.7 (s, C3, Ph), 127.6 (s, Xy), 125.2 (s, Xy),
1
117.0 (q, JFC ) 293.4 Hz, CF3), 17.8 (s, Me). 19F NMR (282.4
MHz, CDCl3): δ -74.9 (s). 31P{1H} NMR (121.5 MHz, CDCl3):
1
2
δ 31.0 (d, JRhP ) 122.9 Hz).
(282.4 MHz, C6D6): δ -9.6 (d, JRhF ) 24.3 Hz).
[Rh(CF3)(CNXy)3] (6). Method A. A solution of [RhF-
(COD)(PPh3)] (251 mg, 0.51 mmol) in THF (6 mL) was treated
with Me3SiCF3 (0.51 mL of a 2.0 M solution in THF, 1.02
mmol) at room temperature and stirred for 5 min. XyNC (207
mg, 1.58 mmol) was added, and after the mixture was stirred
for 45 min, the volatiles were removed under vacuum. The
residue was dissolved in THF (5 mL) and the solution treated
with H2O2 (44 µL, 35%, 0.51 mmol). After it was stirred for 30
min at room temperature, the solution was concentrated to
dryness under vacuum and the residue treated with EtOH (2
mL) to give a yellow solid, which was filtered, washed with
EtOH (2 × 2 mL), and dried under vacuum. Yield: 159 mg,
55%.
[Rh(CF3)(CNXy)3(η2-TCNE)] (8). A solution of 6 (85 mg,
0.15 mmol) in THF (4 mL), was treated with TCNE (20 mg,
0.16 mmol) at room temperature. The resulting yellow solution
was stirred for 1 h and concentrated to dryness under vacuum.
Et2O (5 mL) was added to precipitate a pale yellow solid, which
was washed with Et2O (2 × 5 mL) and dried under vacuum.
Yield: 97 mg, 93%. Mp: 168-170 °C dec. Anal. Calcd for
C34H27N7F3Rh: C, 58.88; H, 3.92; N, 14.14. Found: C, 59.00;
H, 4.21; N, 13.73. IR (Nujol, cm-1): ν(CtNXy) 2182 (s), ν(Ct
N, TCNE) 2206 (s). 1H NMR (400.9 MHz, CDCl3): δ 7.37-
7.09 (two AB2 m, 9 H, Xy), 2.522 (s, 6 H, Me), 2.515 (s, 12 H,
Me). 13C{1H} NMR (100.8 MHz, CDCl3): δ 137.1, 135.9 (C2
Xy), 130.9, 128.5, 128.3 (C3 + C4 Xy), 117.3, 116.2 (C1 Xy),

Reactivity of Rh(I) Trifluoromethyl Complexes
Organometallics, Vol. 24, No. 23, 2005 5643
18.6 (Me); the signals of CF3 and CtN carbons were not
observed. 19F NMR (282.4 MHz, CDCl3): δ 1.7 (d, 2JRhF ) 14.2
Hz).
vacuum. n-Pentane (5 mL) was added to precipitate an oil,
which was converted into a yellow solid by stirring for 15 min
at 0 °C. The solid was washed with n-pentane (2 × 5 mL) and
dried under vacuum. Yield: 145 mg, 89%. Mp: 191-195 °C.
Anal. Calcd for C32H27N3F12IRh: C, 42.17; H, 2.99; N, 4.61.
Found: C, 42.25; H, 3.20; N, 4.80. IR (Nujol, cm-1): ν(CtN)
2204 (s). 1H NMR (300.1 MHz, CDCl3): δ 7.27-7.11 (two AB2
m, 9 H, Xy), 2.54 (s, 12 H, Me, Xy), 2.51 (s, 6 H, Me, Xy). 13C-
{1H} NMR (100.8 MHz, CDCl3): δ 136.8 (C2, 2 Xy), 136.5 (C2,
Xy), 130.3 (C4, 2 Xy), 128.3 (C3, Xy), 128.2 (C3, 2 Xy), 126.0
(C1, 2 Xy), 18.9 (Me, Xy), 18.7 (Me, 2 Xy); the C1 and C4
signals of the single Xy group are probably overlapped with
[Rh(CF3)(CNXy)3(η2-MA)] (9). A solution of 6 (72 mg, 0.13
mmol) in THF (10 mL) was treated with MA (14 mg, 0.14
mmol) at room temperature. The resulting pale yellow solution
was stirred for 1 h and evaporated to dryness under vacuum.
Et2O (3 mL) was added to precipitate a pale yellow solid which
was washed with Et2O (3 mL) and dried under vacuum.
Yield: 60 mg, 71%. Mp: 166-168 °C dec. Anal. Calcd for
C32H29N3F3O3Rh: C, 57.93; H, 4.41; N, 6.33. Found: 58.16;
H, 4.49; N, 6.33. IR (Nujol, cm-1): ν(CtN) 2188 (s), 2162 (s),
2146 (s), ν(C)O) 1808 (s), 1746 (s). 1H NMR (300.1 MHz,
CDCl3): δ 7.23-7.06 (two AB2 m, 9 H, Ar, Xy), 4.26 (br s, 2 H,
CHdCH), 2.48 (s, 12 H, Me), 2.39 (s, 6 H, Me). 13C{1H} NMR
(100.8 MHz, CDCl3): δ 175.6 (s, CdO), 151.8 (br d, 1JRhC ) 49
Hz, XyNC), 150.0 (br s, XyNC), 135.5 (s, Xy), 135.4 (s, Xy),
129.7 (s, Xy), 129.3 (s, Xy), 128.0 (s, Xy), 127.2 (s, Xy), 126.3
(s, Xy), 18.63 (s, Me), 18.58 (s, Me); the signal of CF3 carbon
was not observed. 19F NMR (282.4 MHz, CDCl3): δ -11.9 (d,
2JRhF ) 9.3 Hz).
others; those of the CtN, CF3, and C4F9 carbons were not
2
observed. 19F NMR (282.4 MHz, CDCl3): δ -8.1 (dtt, JRhF
)
13.6, 4JFF ) 7.3, 5JFF ) 3.7 Hz, Rh-CF3), -66.3 (m, Rh-CF2),
-81.3 (tt, JFF ) 9.3, JFF ) 4.6 Hz, CF3), -113.2 (m, â-CF2),
-125.2 (m, γ-CF2).
4
5
Crystallography. Compounds 2-4 and 12 were measured
on a Bruker Smart Apex CCD machine. Data were collected
using monochromated Mo KR radiation in ω-scan mode. The
structures of compounds 2 and 3 were solved by the heavy-
atom method and the structures of 4 and 8 were solved by the
direct method, and all were refined anisotropically on F2.
Methyl groups were refined using rigid groups. Other hydro-
gens were refined using a riding mode.
Complex 12 contains an ill-resolved CHCl3 molecule which
is disordered over two positions with a ca. 61:39 distribution.
The highest residual electron density (2.16 e Å-3) is near one
of its chlorine atoms. The CF3-CF2 group of the n-C4F9 ligand
is disordered over two positions; therefore, appropriate simi-
larity restraints were employed.
[Rh(CF3)(Me)I(CNXy)3] (10). A solution of 6 (72 mg, 0.13
mmol) in THF (10 mL) was treated with MeI (12 µL, 0.19
mmol) at room temperature. The resulting pale yellow solution
was stirred for 1 h and then evaporated to dryness under
vacuum. n-Pentane (5 mL) was added to precipitate an oil,
which was converted into a pale yellow solid by stirring for 15
min at 0 °C. The solid was washed with n-pentane (2 × 5 mL)
and dried under vacuum. Yield: 89 mg, 79%. Mp: 226-228
°C dec. Anal. Calcd for C29H30N3F3IRh: C, 49.24; H, 4.27; N,
5.94. Found: C, 49.57; H, 4.48; N, 5.86. IR (Nujol, cm-1): ν-
(CtN) 2178 (s). 1H NMR (300.1 MHz, CDCl3): δ 7.23-7.10
(two AB2 m, 9 H, Xy), 2.52 (s, 12 H, Me, Xy), 2.51 (s, 6 H, Me,
Xy), 1.41 (d, 3 H, 2JRhH ) 3.3 Hz, Me-Rh). 13C{1H} NMR (50.3
MHz, CDCl3): δ 136.0 (C4, 2 Xy), 135.7 (C4, Xy), 129.8 (C2,
Xy), 129.7 (C2, 2 Xy), 128.2 (C3, Xy), 128.0 (C3, 2 Xy), 126.4
(br s, C1, 2 Xy), 18.9 (Me, Xy), 18.8 (Me, 2 Xy), -8.1 (dq, Me-
Crystal data for complexes 2-4 and 12 are given in Table
2.
Acknowledgment. We thank the Direccio´n General
de Investigacio´n/FEDER for financial support (Grant
CTQ2004-05396 and a “Ramo´n y Cajal” contract to J.G.-
R.) and Fundacio´n Se´neca for a grant to J.G.-L.
1
3
Rh, JRhC ) 20.6 Hz, JCF ) 5.5 Hz); the C1 signal of the
equatorial Xy group is probably overlapped with other signals;
the CF3 and CtN signals were not observed. 19F NMR (282.4
2
MHz, CDCl3): δ -11.2 (d, JRhF ) 15.8 Hz).
Supporting Information Available: Crystallographic
files in CIF format for compounds 2-4 and 12. This material
is available free of charge via the Internet at http://pubs.acs.org.
[Rh(CF3)(n-C4F9)I(CNXy)3] (11). A solution of 6 (101 mg,
0.18 mmol) in THF (5 mL) was treated with n-C4F9I (34 µL,
0.20 mmol) at room temperature. The resulting yellow solution
was stirred for 1 h and then evaporated to dryness under
OM050573Q