Activation of C-F and C-H Bonds by platinum in trifluorinated [C,N,N′] ligands. Crystal structures of [PtFMe2{Me2NCH2CH2NHCH(CH 2COMe)(2,4-C6H2F2)}] and [PtMe{Me2

Article abstract of DOI:10.1021/om960803o

Trifluorinated ligands Me₂NCH₂CH₂N=CHR (R = 2,4,6-C₆H₂F₃ (2a), 2,3,6-C₆H₂F₃ (2b)) react with [Pt₂Me₄(μ-SMe₂)₂] (

Full text of DOI:10.1021/om960803o

Organometallics 1997, 16, 1233-1240
1233
Activa tion of C-F a n d C-H Bon d s by P la tin u m in
Tr iflu or in a ted [C,N,N′] Liga n d s. Cr ysta l Str u ctu r es of
[P tF Me2{Me2NCH2CH2NHCH(CH2COMe)(2,4-C6H2F 2)}]
a n d [P tMe{Me2NCH2CH2NdCH(2,3,4-C6HF 3)}]
Olga Lo´pez and Margarita Crespo*
Departament de Qu´ımica Inorga`nica, Universitat de Barcelona, Diagonal 647,
08028 Barcelona, Spain
Merce` Font-Bard´ıa and Xavier Solans
Departament de Cristal.lografia, Mineralogia i Dipo`sits Minerals, Universitat de Barcelona,
Martı´ i Franque´s s/ n, 08028 Barcelona, Spain
Received September 20, 1996X
Trifluorinated ligands Me2NCH2CH2NdCHR (R ) 2,4,6-C6H2F3 (2a ), 2,3,6-C6H2F3 (2b))
react with [Pt2Me4(µ-SMe2)2] (1) to yield the [C,N,N′] saturated cyclometalated platinum(IV)
compounds [PtFMe2{Me2NCH2CH2NHCH(CH2COMe)(C6H2F2)}] (4) arising from CsF bond
activation followed by acetone addition on the iminic bond of the coordinated ligand. The
reactions of the platinum substrate with trifluorinated ligands Me2NCH2CH2NdCHR (R )
2,3,4-C6H2F3 (2c), 2,4,5-C6H2F3 (2d ), 3,4,5-C6H2F3 (2e)) containing only one or no fluorine
atom in the ortho positions yield the [C,N,N′] cyclometalated platinum(II) compounds [PtMe-
(Me2NCH2CH2NdCHC6HF3)] (5) by ortho metalation with loss of methane. Compounds 5
react with methyl iodide to yield the [C,N,N′] unsaturated cyclometalated platinum(IV)
compounds [PtIMe2(Me2NCH2CH2NdCHC6HF3)] (6) and with triphenylphosphine to produce
the displacement of the NMe2 moiety and the formation of [C,N] cyclometalated compounds
[PtMe(PPh3)(Me2NCH2CH2NdCHC6HF3)] (7c). When there is a fluorine atom adjacent to
platinum (F5), the displacement of both nitrogen donor atoms takes place upon reaction
with PPh3 to yield the compounds [PtMe(PPh3)2(Me2NCH2CH2NdCHC6HF3)] (7d ,e). All
compounds were characterized by elemental analyses and NMR spectroscopy, and [PtFMe2{Me2-
NCH2CH2NHCH(CH2COMe)(2,4-C6H2F2)}] (4a ) and [PtMe{Me2NCH2CH2NdCH(2,3,4-C6-
HF3)}] (5c) were characterized crystallographically.
In tr od u ction
NCH2CH2NdCHC6F5 at electron-rich metal centers,
such as W(0)4 and Pt(II).5 While intramolecular activa-
tion of C-F bonds at W(0) can be extended to substrates
containing only difluoro- or monofluoro-substituted
aromatic rings,6 such processes fail at Pt(II). In the
latter case, either no reaction occurs, as for the ligand
Me2NCH2CH2NdCH(2,6-C6H3F2), or C-H bond activa-
tion takes place, as for the ligand Me2NCH2CH2NdCH-
(2-C6H4F).5 On the other hand, attempts to achieve
intramolecular activation of aryl C-X or aryl C-H
bonds in related saturated ligands Me2NCH2CH2N(Me)-
CH2R have been unsuccessful both at platinum(II)7 and
at tungsten(0).8 The greater tendency to form unsatur-
ated metallacycles containing the CdN group (endo-
cycles) than saturated metallacycles has been attributed
to restricted rotation about the CdN bond and to
conjugation of the CdN bond with the aryl ring.9
In spite of the fact that aryl C-F bonds are among
the strongest known, a number of systems capable of
activating these bonds have been reported and the
subject has recently been reviewed.1 Interest in this
field arises from the fact that carbon-fluorine bond
activation is a fundamental step in the development of
metal-based catalysts for the functionalization of orga-
nofluorine compounds.2 Moreover, the resulting fluoride
complexes might function as metal-based receptors for
organic molecules, since it has been shown that tungsten-
bound fluoride shows a propensity to engage in hydro-
gen bonding.3
The ability to produce chelated-assisted aryl C-F
oxidative-addition processes has been attributed to the
basicity, chelating nature, and restricted conformation
of the ligand, as well as to the perfluorination of the
aryl ring. For instance, successful intramolecular C-F
bond activation has been reported for the ligand Me2-
(4) Osterberg, C. E.; King, M. A.; Arif, A. M.; Richmond, T. G. Angew.
Chem., Int. Ed. Engl. 1990, 29, 888.
(5) Anderson, C. M.; Crespo, M.; Ferguson, G.; Lough, A. J .;
Puddephatt, R. J . Organometallics 1992, 11, 1177.
(6) Lucht, B. L.; Poss, M. J .; King, M. A.; Richmond, T. G. J . Chem.
Soc., Chem. Commun. 1991, 400.
* To whom correspondence should be addressed. E-mail: mcrespo@
kripto.qui.ub.es.
X Abstract published in Advance ACS Abstracts, February 15, 1997.
(1) Kiplinger, J . L.; Richmond, T. G.; Osterberg, C. E. Chem. Rev.
1994, 94, 373.
(2) (a) Kiplinger, J . L.; King, M. A.; Arif, A. M.; Richmond, T. G.
Organometallics 1993, 12, 3382. (b) Kiplinger, J . L.; Richmond, T. G.;
Arif, A. M.; Du¨cker-Reuter, C.; van Eldik, R. Organometallics 1996,
15, 1545.
(7) Crespo, M. Polyhedron 1996, 15(12), 1981.
(8) Poss, M. J .; Arif, A. M.; Richmond, T. G. Organometallics 1988,
7, 1669.
(9) Buffin, B. P.; Poss, M. J .; Arif, A. M.; Richmond, T. G. Inorg.
Chem. 1993, 32, 3805.
(3) Richmond, T. G. Coord. Chem. Rev. 1990, 105, 221.
S0276-7333(96)00803-5 CCC: $14.00 © 1997 American Chemical Society

1234 Organometallics, Vol. 16, No. 6, 1997
Lo´pez et al.
Sch em e 1
compounds [PtFMe2{Me2NCH2CH2NHCH(CH2COMe)-
(2,4-C6H2F2)}] (4a ) and [PtFMe2{Me2NCH2CH2NHCH-
(CH2COMe)(2,5-C6H2F2)}] (4b ), respectively, as in-
soluble white compounds which were characterized by
elemental analysis, IR, and FAB-MS and an X-ray
determination for 4a . Compounds 4 were sufficiently
soluble in CDCl3 solution so as to be characterized by
1H and 19F (4b) NMR spectroscopy. The presence of
ketone and NH groups is confirmed by IR spectroscopy.
Two methyl resonances were observed with 2J (PtH)
values in the range 63-70 Hz. These resonances
appear as singlets for 4a , but for 4b, the axial methyl
resonance appears as a doublet and the equatorial
methyl resonance appears as a doublet of doublets due
to couplings with one (F6) or with two (F6 and F5)
fluorine atoms. All protons in both NMe2 and CH2CH2
groups are diastereotopic, and all resonances could be
assigned by 1H-1H COSY experiments. For 4b, the
presence of a PtsF bond was further proved by the
observation of a resonance in the 19F NMR spectrum at
-235 ppm. Although 4a was not soluble enough to run
a
19F NMR spectrum and no couplings with fluorine
1
were observed in the H NMR spectrum, the presence
of a PtsF bond was confirmed in the solid state by the
crystal structure determination. The lack of hydrogen-
fluorine couplings may suggest that the fluorine dis-
sociates from the platinum atom center in solution. In
the FAB mass spectra of compounds 4, the molecular
peak was not observed but fragments corresponding to
loss of a fluorine atom were present in both cases.
The formation of compounds 4 involves CsF bond
activation and subsequent cis addition of a CsH bond
of acetone across the CdN bond of the coordinated
ligand. It has been suggested that for the analogous
pentafluorophenyl derivative the latter process is in-
duced by coordination to platinum(IV) and by the
strongly electronegative pentafluorophenyl group. Our
present result shows that this unusual addition of a
CsH bond of acetone to an imine group takes place also
for less fluorinated terdentate [C,N,N′] systems. It is
worth noting that this process does not take place for
the compound [PtFMe2(PhCH2NdCHC6F4)(SMe2)] con-
taining a bidentate [C,N] metallacycle. The strain of
the rigid [C,N,N′] imine ligand coordinated in a meridi-
onal fashion induces the addition of acetone to the imine
so that the more flexible resulting saturated ligand may
adopt a facial coordination. Both facial and meridional
coordination have been reported for related [C,N,N′]
saturated ligands.11
In spite of the fact that CsF activation in saturated
ligands has been reported to be unsuccessful, the stable
saturated cyclometalated compounds 4a and 4b can be
obtained via formation of an endo-cycle followed by
addition of acetone. This result indirectly proves that
CsF activation reactions are governed by kinetic rather
than thermodynamic factors. Mechanistic studies for
related systems have recorded greater negative activa-
tion entropy values for the formation of saturated
metallacycles than for that of unsaturated cycles.12
Since 4b consists of a single isomer and the equatorial
methyl is coupled to F6 and F5, it may be assumed that
of the two non-equivalent ortho C-F bonds in 2b, only
In order to gain further insights into the scope and
limitations of the chelate-assisted oxidative addition of
C-F bonds and into the competitive C-H bond activa-
tion, we decided to extend our studies to several trifluoro
derivatives Me2NCH2CH2NdCH(C6H2F3). Trifluoroaryl
groups containing two, one, or no fluorine atom in the
ortho positions were selected for this study. Results for
related ligands with a single nitrogen donor, RCHd
NCH2Ph, have been reported elsewhere,10 and hence a
comparison between bidentate [C,N] and terdentate
[C,N,N′] systems could be established.
Resu lts a n d Discu ssion
The ligands Me2NCH2CH2NdCHR were prepared
from reaction of the corresponding aldehyde and di-
methylethylenediamine in toluene and were character-
1
ized by H and 19F NMR spectra and MS/CI.
Rea ction s of th e Liga n d s Me2NCH2CH2NdCHR
(R ) 2,4,6-C6H2F 3, 2,3,6-C6H2F 3). The reactions of
[Pt2Me4(µ-SMe2)2] (1) with ligands Me2NCH2CH2NdCHR
(R ) 2,4,6-C6H2F3 (2a ), 2,3,6-C6H2F3 (2b)) were carried
out in acetone solution at room temperature, and the
results are summarized in Scheme 1. Compounds
[PtMe2(Me2NCH2CH2NdCHR)] (3) could be detected in
acetone-d6 solution when the reactions were monitored
by 1H NMR. As reported for analogous compounds,5 two
2
methylplatinum resonances were observed with J (PtH)
values of 84 and 92 Hz. The imine proton also couples
with 195Pt. Resonances for CH2 and aromatic protons
are overlapped with those of the unreacted ligand. The
reaction proceeds in acetone solution to yield the
(11) Alsters, P. L.; Engel, P. F.; Hogerheide, M. P.; Copijn, M.; Spek,
A. L.; van Koten, G. Organometallics 1993, 12, 1831.
(12) Crespo, M.; Martinez, M.; Sales, J .; Solans, X.; Font-Bard´ıa,
M. Organometallics 1992, 11, 1288.
(10) (a) Crespo, M.; Martinez, M.; Sales, J . Organometallics 1993,
12, 4297. (b) Crespo, M.; Solans, X.; Font-Bard´ıa, M. Organometallics
1995, 14, 355.

Activation of C-F and C-H Bonds by Platinum
Organometallics, Vol. 16, No. 6, 1997 1235
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Com p ou n d 4a
Pt-C(1)
1.973(3)
2.031(5)
2.046(4)
2.079(2)
2.160(3)
2.256(3)
1.205(5)
1.378(4)
1.342(5)
1.475(4)
N(1)-C(8)
N(2)-C(9)
C(6)-C(7)
C(7)-C(12)
C(8)-C(9)
C(12)-C(13)
C(13)-C(14)
N(1)-H(1)
N(1)-F(3*)
H(1)-F(3*)
1.495(5)
1.509(5)
1.519(4)
1.538(4)
1.501(5)
1.484(5)
1.478(6)
0.99(4)
Pt-C(15)
Pt-C(16)
Pt-F(3)
Pt-N(1)
Pt-N(2)
O-C(13)
F(1)-C(3)
F(2)-C(5)
N(1)-C(7)
2.74(5)
1.76(4)
C(1)-Pt-C(15)
C(1)-Pt-C(16)
C(15)-Pt-C(16)
C(1)-Pt-F(3)
C(15)-Pt-F(3)
C(16)-Pt-F(3)
C(1)-Pt-N(1)
C(15)-Pt-N(1)
C(16)-Pt-N(1)
F(3)-Pt-N(1)
C(1)-Pt-N(2)
C(15)-Pt-N(2)
C(16)-Pt-N(2)
F(3)-Pt-N(2)
N(1)-Pt-N(2)
C(7)-N(1)-Pt
C(8)-N(1)-Pt
89.0(2)
97.0(2)
87.4(2)
C(9)-N(2)-Pt
C(6)-C(1)-Pt
C(3)-C(2)-C(1)
103.8(2)
114.1(2)
120.6(4)
123.3(4)
119.9(3)
110.2(3)
110.1(3)
112.7(3)
110.3(3)
110.9(3)
114.2(3)
121.5(4)
121.9(3)
174.31(10) C(4)-C(3)-C(2)
89.9(2)
88.6(2)
83.18(13) N(1)-C(7)-C(12)
95.2(2)
C(1)-C(6)-C(7)
N(1)-C(7)-C(6)
C(6)-C(7)-C(12)
N(1)-C(8)-C(9)
177.5(2)
91.36(11) C(8)-C(9)-N(2)
92.64(14) C(13)-C(12)-C(7)
176.78(14) O-C(13)-C(14)
F igu r e 1. View of the molecular structure of compound
4a .
95.1(2)
O-C(13)-C(12)
88.20(11) C(14)-C(13)-C(12) 116.6(4)
82.31(13) Pt-N(1)-H(1)
110.1(2)
107.1(2)
ligand. The saturated tridentate [C,N,N′] ligand adopts
a facial coordination.
105.0(2)
174(2)
N(1)-H(1)-F(3*)
Molecular dimensions are given in Table 1. The
angles between adjacent atoms in the coordination
sphere of platinum lie in the range 82.31(13)-97.0(2)°;
the smallest angles correspond to the terdentate ligand.
The metallacycle has an envelope structure, and dis-
placements from the least-squares plane are as fol-
lows: Pt, -0.034; N(1), 0.025; C(1), 0.052; C(6), -0.043;
C(7), -0.227 Å. A comparison of structural features for
4a and related saturated or unsaturated platinum(IV)
metallacycles is presented in Table 2. All bond dis-
tances and angles in the coordination sphere of platinum
are in the expected range for this type of compound.
Although differences are not significant, the PtsF bond
distance is slightly longer (2.079(2) Å) than in [PtF-
Me2{Me2NCH2CH2NHCH(CH2COMe)C6F4}] (2.070(5)
Å),5 in agreement with the greater trans influence of a
less fluorinated group (see Table 2).
that having a fluorine atom in the adjacent position is
selectively activated. This fact shows that the electron-
withdrawing effect of the adjacent fluorine atom, induc-
tive in nature, is decisive in enhancing the reactivity of
C-F bonds. Moreover, the fluorine atom at position 5,
may be crucial in preventing the solvolysis of the Pt-F
bond observed for 4a .
Cr ysta l Str u ctu r e of 4a . Suitable crystals of 4a
were grown in acetone solution. The crystal structure
is composed of pairs of molecules forming centrosym-
metric dimers. H(1) was located from a difference
synthesis and refined isotropically. The value of the
angle N(1)-H(1)-F(3*) is 174(2)°, and the short H(1)‚‚‚F-
(3*) distance between pairs of molecules (1.76(4) Å) is
indicative of intermolecular hydrogen bonding. The
basicity of the fluoride in analogous tungsten systems
has been attributed to the inability of the 18-electron
metal center to accept π-donation from the fluoride, and
thus it is expected to increase if fluorination of the aryl
ring decreases.13 Although the difference is not signifi-
cant, a shorter N(1)‚‚‚F(3*) distance between pairs of
molecules (2.74(5) Å) is obtained for 4a as compared to
[P t F Me2 {Me2 N CH 2 CH 2 N H CH (CH 2 COMe)C6 F 4 }]
[2.805(10) Å].5 The molecular structure is shown in
Figure 1 and confirms the geometry predicted from
spectroscopic and analytical data. The platinum atoms
are octahedrally coordinated by three carbon atoms in
a facial arrangement, two nitrogen atoms, and a fluoride
Rea ction s of th e Liga n d s Me2NCH2CH2NdCHR
(R ) 2,3,4-C6H2F 3, 2,4,5-C6H2F 3, 3,4,5-C6H2F 3). The
reactions of [Pt2Me4(µ-SMe2)2] (1) with ligands Me2-
NCH2CH2NdCHR (R ) 2,3,4-C6H2F3 (2c), 2,4,5-C6H2F3
(2d ), 3,4,5-C6H2F3 (2e)) were carried out in acetone or
toluene solution at room temperature, and the results
are summarized in Scheme 2. In this case, as described
for ligands 2a and 2b, the compounds [PtMe2(Me2NCH2-
CH2NdCHR)] (3) could also be detected. In all cases,
platinum(II) compounds [PtMe(Me2NCH2CH2NdCHR)]
(5) were formed due to CsH bond activation followed
Ta ble 2. Bon d Len gth s (Å) a n d Bon d An gles (d eg) for Cyclom eta la ted P la tin u m (IV) a n d P la tin u m (II)
Com p ou n d s
Pt-X
Pt-N
Pt-C(Ar) Pt-Me N(1)-Pt-C(Ar) N(1)-Pt-N(2)
[PtFMe2{Me2NCH2CH2NHCH(CH2COCH3)R}] (4a ; R ) 2,4-C6H2F2) 2.079(2) 2.160(3)a 1.973(3) 2.046(4)b
83.18(13)
82.7(4)
81.7(5)
80.9(3)
78.4(4)
82.31(13)
81.5(4)
81.2(4)
82.1(3)
2.256(3)c 2.031(5)d
2.070(5) 2.173(9)a 1.978(9) 2.060(14)b
2.242(10)c 2.038(14)d
2.456(3) 2.045(13)a 1.999(12) 2.068(15)b
[PtFMe2{Me2NCH2CH2NHCH(CH2COCH3)R}]e (R ) C6F4)
[PtClMe2{Me2NCH2CH2NdCHR}]f (R ) 2-C6H3Cl)
[PtMe(Me2NCH2CH2NdCHR] (5c; R ) 2,3,4-C6HF3)
[PtMe(PPh3)(RCHdNCH2Ph)]g (R ) 2,3,4-C6HF3)
2.254(11)c
2.036(13)d
2.009(6)a 1.996(8) 2.040(8)b
2.160(7)c
2.156(8)a 2.026(8) 2.118(9)b
a
b
d
g
N(1), NH, or imine. Me trans to N(1). c N(2), NMe2. Me trans to N(2). e Reference 5. f Reference 14. Reference 10b.

1236 Organometallics, Vol. 16, No. 6, 1997
Lo´pez et al.
Sch em e 2
F igu r e 2. View of the molecular structure of compound
5c.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Com p ou n d 5c
Pt-C(1)
1.996(8)
2.009(6)
2.040(8)
2.160(7)
1.357(12)
1.350(11)
F(3)-C(5)
N(2)-C(9)
N(1)-C(7)
N(1)-C(8)
C(6)-C(7)
C(8)-C(9)
1.355(10)
1.460(13)
1.285(11)
1.459(11)
1.471(12)
1.532(13)
Pt-N(1)
Pt-C(12)
Pt-N(2)
F(1)-C(3)
F(2)-C(4)
C(1)-Pt-N(1)
C(1)-Pt-C(12)
N(1)-Pt-C(12)
C(1)-Pt-N(2)
N(1)-Pt-N(2)
C(12)-Pt-N(2)
C(9)-N(2)-Pt
C(7)-N(1)-C(8)
80.9(3)
98.8(4)
178.5(3)
163.0(3)
82.1(3)
98.1(3)
103.1(5)
126.5(7)
C(7)-N(1)-Pt
C(8)-N(1)-Pt
C(6)-C(1)-Pt
C(1)-C(6)-C(7)
N(1)-C(7)-C(6)
N(1)-C(8)-C(9)
N(2)-C(9)-C(8)
117.8(6)
115.7(5)
112.0(6)
115.4(7)
113.8(7)
106.6(6)
112.3(7)
by methane elimination, as already reported for analo-
gous systems.10,14 Compounds 5 were characterized by
1
elemental analysis, FAB-MS, and H and 19F NMR and
UV-visible spectra. Compound 5c was also character-
ized crystallographically. The single platinum-methyl
is -0.0095 Å for N(1). The metallacycle is nearly
coplanar with the coordination plane, the dihedral angle
being 0.28°. The angles between adjacent atoms in the
coordination sphere of platinum lie in the range 80.9(3)-
98.8(4)°, the smallest angles corresponding to the ter-
dentate ligand. Bond lengths and angles are well within
the range of values obtained for analogous cyclometa-
lated platinum(II) compounds.10b,15 A comparative study
of structural features for 5c and [PtMe(PPh3)(2,3,4-C6-
HF3CHdNCH2Ph)] is presented in Table 2. An analysis
of these values reveals that PtsN and PtsC bond
lengths are shorter for the terdentate [C,N,N′] than for
the bidentate [C,N] system, and in the former the
metallacycle is smaller (perimeter 8.177 Å versus 8.305
Å). This fact, as well as the greater distortion of the
coordination sphere of the platinum in the PPh3 deriva-
tive, is consistent with the steric requirements of the
bulky phosphine. On the other hand, differences in the
PtsN and PtsC bond lengths between related platinu-
m(II) and platinum(IV) compounds are not significant.
1
resonance, coupled with 195Pt, appears in the H NMR
as a singlet for 5c and as a doublet (due to coupling with
one fluorine atom) for 5d and 5e. Three distinct fluorine
signals appear in the aromatic region in the 19F NMR
spectra.
Ligands 2c and 2d could lead either to CsF or to
CsH bond activation. The exclusive formation of the
platinum(II) compounds indicate that CsH bond activa-
tion is most favored, even when an electron-withdraw-
ing fluorine substituent is present in a position adjacent
to the CsF bond (2c). These results together with those
previously obtained for fluorinated ligands Me2NCH2-
CH2NdCHR (R ) C6F5, 2,6-C6H3F2)5 indicate that CsF
bond activation is produced only if the aryl ring contains
at least three fluorine atoms, two of them in ortho
positions. Analogous results have been obtained for
related ligands with the single nitrogen donor
RCHdNCH2Ph.10
Cr ysta l Str u ctu r e of 5c. Suitable crystals of 5c
were grown in toluene solution. The crystal structure
is composed of discrete molecules separated by van der
Waals distances. The structure is shown in Figure 2,
and molecular dimensions are listed in Table 3. The
coordination sphere of platinum is square-planar. The
metallacycle is approximately planar; the largest devia-
tion from the mean plane determined by the five atoms
Rea ctivity of th e Cyclom eta la ted Com p ou n d s 5.
It has been shown that potentially terdentate chelating
ligands [N,C,N′]16 and [C,N,N′]17 may adopt different
bonding modes and hapticities, which is relevant in
(15) (a) Stoccoro, S.; Cinellu, M. A.; Zucca, A.; Minghetti, G.;
Demartin, F. Inorg. Chim. Acta 1994, 215, 17. (b) Canty, A. J .;
Minchin, N. J .; Patrick, J . M.; White, A. H. J . Chem. Soc., Dalton Trans.
1983, 1253. (c) Navarro-Ranninger, C.; Lo´pez-Solera, I.; Alvarez-
Valde´s, A.; Rodr´ıguez-Ramos, J . M.; Massaguer, J . R.; Garc´ıa-Ruano,
J . L.; Solans, X. Organometallics 1993, 12, 4104.
(13) Osterberg, C. E.; Arif, A. M.; Richmond, T. G. J . Am. Chem.
Soc. 1988, 110, 6903.
(14) Anderson, C. M.; Crespo, M.; J ennings, M. C.; Lough, A. J .;
Ferguson, G.; Puddephatt, R. J . Organometallics 1991, 10, 2672.
(16) van Koten, G. Pure Appl. Chem. 1989, 61(10), 1681.

Activation of C-F and C-H Bonds by Platinum
Organometallics, Vol. 16, No. 6, 1997 1237
ppm with platinum satellites (3J (H-Pt) ) ca. 50 Hz)
and indicates that the addition of acetone to the CdN
bond of the ligand, as observed in compounds 4, does
not take place in this system. In the 19F NMR, three
distinct resonances appear in the aromatic region, and
J (F-Pt) values are smaller than for the corresponding
platinum(II) compounds.
Sch em e 3
The reactions of compounds 5 with triphenylphos-
phine are summarized in Scheme 4. Compound 5c
reacted with PPh3 in a 1:1 molar ratio in acetone
solution to yield compound 7c, which results from a
displacement reaction of the NMe2 moiety for PPh3. The
lability of the PtsNMe2 bond has previously been
proved for platinum(IV) compounds containing a me-
ridional [C,N,N′] tridentate ligand.14 Compound 7c is
a yellow solid that was characterized by elemental
relation to catalytic processes. In order to explore the
bonding abilities of the terdentate Me2NCH2CH2NdCHR
in these systems, we studied the reactivity of the
cyclometalated compounds 5.
1
analysis and H, 19F, and 31P NMR. Both the methyl
and the imine groups are coupled with 195Pt, and the
methyl group appears as a doublet due to coupling with
the phosphorus atom. No platinum satellites are ob-
served for the dimethylamino group, thus ruling out the
possibility of pentacoordination of the platinum. The
presence of PPh3 coordinated to platinum is further
confirmed by 31P NMR.
The reactions of compounds 5 with methyl iodide were
carried out in acetone solution and are summarized in
Scheme 3. Oxidative addition of alkyl halides to plati-
num(II) substrates is well-documented; in particular,
studies concerning compounds [PtMe2(NN)] (where NN
is a bidentate nitrogen donor) have been reported, and
experimental evidence points to trans stereochemistry
in the resulting platinum compounds.7,18 This process
is inhibited by steric hindrance or by the presence of
highly electron-withdrawing groups, as in [Pt(4-CF3-
C6H4)2(NN)].19 Studies of cyclometalated platinum(II)
compounds have also been reported to yield platinu-
m(IV) compounds20 or, more unexpectedly, either an
arenonium platinum(II) compound or zwitterionic di-
nuclear platinum complexes arising from dissociation
of the amine arm of the ligand.21
Upon addition of methyl iodide to a solution of
compounds 5 in acetone, the color of the solution rapidly
changed from red to yellow, and platinum(IV) com-
pounds [PtIMe2(Me2NCH2CH2NdCHC6HF3)] (6) were
isolated. Thus, in these systems, the electron-with-
drawing fluorine substituents do not prevent the oxida-
tive addition. Compounds 6 were characterized by
elemental analysis and NMR spectroscopy. The meth-
yl-platinum resonances show couplings with 195Pt, and
2J (H-Pt) values are consistent with the oxidation state
of platinum. In addition, for 6d and 6e, the equatorial
methyl is coupled with one fluorine atom (F5). As
reported for analogous compounds, the methyl trans to
iodide appears at higher fields as compared to the
methyl groups trans to nitrogen atoms. Dissociation
and methylation of the amine arm of the terdentate
ligand may be disregarded, since diastereotopic methyl
groups of the NMe2 unit are coupled with platinum. The
resonance due to the imine proton appears at δ ca. 9
Compounds 5d and 5e, however, under the same
reaction conditions gave compounds 7d and 7e, in which
both nitrogen atoms were displaced by 2 equiv of PPh3,
along with platinum(0) and free ligand. Attempts to
obtain compounds containing 1 equiv of PPh3 were
unsuccessful. Compounds 7d and 7e, best obtained
from reaction of the corresponding compound 5 with 2
equiv of PPh3, are white solids which were characterized
1
by elemental analysis and H, 19F, and 31P NMR. The
methyl group is coupled with two nonequivalent phos-
phorus atoms and is also coupled with 195Pt. Both
dimethylamino and imine groups lack platinum satel-
lites. The 31P NMR spectra show two sets of resonances
due to the nonequivalent phosphorus atoms, both
coupled with platinum. Spectral evidence points to the
fact that the imine is acting as a monodentate ligand
through the aryl carbon and the planar coordination of
the platinum(II) is completed with one methyl group
and two nonequivalent phosphorus atoms. Large J (F5-
Pt) values for compounds 7d and 7e, in comparison to
the values for cyclometalated compounds 5d and 5e,
arise from a perpendicular orientation of the aryl group
to the coordination plane.
Attempts to obtain an analogous compound for ligand
2c were unsuccessful, since the reaction of 5c with an
excess of PPh3 yielded 7c, which does not react further
with the phosphine. Thus, for compound 5c, the met-
allacycle is not cleaved upon reaction with PPh3. The
differences in reactivity toward PPh3 can be attributed
to the presence of a fluorine atom in the position
adjacent to the PtsC(aryl) bond (F5). An analogous
result has been obtained for the ligands RCHdNCH2-
Ph and has been explained by the unfavorable steric
repulsion between the methyl group and F5 in chelated
[C,N] compounds. The cleavage of the metallacycle
would relieve the steric crowding in the coordination
sphere of platinum.
(17) Wehman-Ooyevaar, I. C. M.; Kapteijn, G. M.; Grove, D. M.;
Smeets, W. J . J .; Spek, A. L.; van Koten, G. J . Chem. Soc., Dalton
Trans. 1994, 703.
(18) (a) Scott, J . D.; Puddephatt, R. J . Organometallics 1985, 4, 1221.
(b) Scott, J . D.; Puddephatt, R. J . Organometallics 1986, 5, 1538. (c)
Crespo, M.; Puddephatt, R. J . Organometallics 1987, 6, 2548.
(19) J awad, J . K.; Puddephatt, R. J . J . Chem. Soc., Dalton Trans.
1977, 1466.
(20) (a) von Zelewsky, A.; Suckling, A. P.; Stoeckli-Evans, H. Inorg.
Chem. 1993, 32, 4585. (b) Wehman, E.; van Koten, G.; Knaap, C. T.;
Ossor, H.; Pfeffer, M.; Spek, A. L. Inorg. Chem. 1988, 27, 4409.
(21) (a) Terheiden, J .; van Koten, G.; Vinke, I. C.; Spek, A. L. J .
Am. Chem. Soc. 1985, 107, 2891. (b) Davidson, M. F.; Grove, D. M.;
van Koten, G.; Spek, A. L. J . Chem. Soc., Chem. Commun. 1989, 1562.
Con clu sion s
Although most examples of C(aryl)sF bond activation
have been reported for systems which meet the condi-

1238 Organometallics, Vol. 16, No. 6, 1997
Lo´pez et al.
Sch em e 4
(19F, 282.22 MHz) spectrometers and referenced to SiMe4 (1H),
tions of perfluorination of the aryl ring and unsaturation
of the formed metallacycle, our results prove that CsF
bond activation can be extended to trifluorinated sys-
tems such as ligands 2a and 2b, leading to the stable
saturated platinum(IV) metallacycles 4a and 4b. The
overall process takes place via CsF bond activation,
followed by addition of acetone to the imine bond. On
the other hand, trifluorinated ligands 2c-escontaining
one or no fluorine atoms in the ortho positionssproduce
exclusively CsH bond activation which, followed by
methane elimination, leads to platinum(II) metalla-
cycles 5. For these compounds, dissociation of the
dimethylamino group from platinum takes place readily
upon reaction with triphenylphosphine. However, the
stronger bond of the iminic nitrogen to platinum is
cleaved only if there is a fluorine atom (F5) adjacent to
the PtsC(aryl) bond in a process similar to that reported
for analogous bidentate [C,N] systems. These results
show that potentially terdentate ligands 2 may adopt
either anionic terdentate [C,N,N′], bidentate [C,N], or
monodentate [C] coordination modes, in addition to
neutral bidentate [N,N′] observed in compounds 3.
Formation of cyclometalated platinum(IV) compounds
6 by oxidative addition of methyl iodide to compounds
5 in acetone is not followed by addition of acetone to
the CdN bond, as observed in compounds 4. Thus, for
this process to take place the presence of both a
terdentate [C,N,N′] and a fluorine ligand coordinated
to platinum(IV) are required, regardless of the fluorina-
tion of the aryl ring. The strain of the rigid [C,N,N′]
imine ligand facilitates this process as well as the easy
cleavage of the PtsNMe2 bond in compounds 5.
CFCl3 (19F), and H3PO4 (31P). δ values are given in ppm and
J
values in Hz. UV-visible spectra were recorded in a
Shimadzu UV-160 A spectrophotometer. IR spectra were
recorded as KBr disks on a Nicolet 520 FT-IR spectrometer.
Microanalyses and mass spectra (CI and FAB) were performed
by the Serveis Cient´ıfico-Te`cnics de la Universitat de Barce-
lona.
P r ep a r a tion of th e Com p ou n d s. The complex [Pt2Me4-
(µ-SMe2)2] (1) was prepared by the method reported in the
literature.22
Compounds 2 were prepared by the reaction of 5 mmol of
the corresponding aldehyde with an equimolecular amount of
dimethylethylenediamine in toluene. After it was stirred for
30 min, the reaction mixtures were dried over anhydrous Na2-
SO4, and the solvent was removed in a rotary evaporator to
yield yellow oils (yield 80-85%).
1
2,4,6-C6H2F 3CHdNCH2CH2NMe2 (2a ). H NMR (CDCl3):
δ 2.31 [s, 6H, Me]; 2.67 [t, 2H, 3J (Hd-He) ) 7, Hd]; 3.78 [t, 2H,
3J (Hd-He) ) 7, He]; 6.70 [t, 2H, 3J (H-F) ) 6, aromatics]; 8.43
3
[s, 1H, Hf]. 19F NMR (CDCl3): δ -110.68 [dd, 2F, J (F-H) )
6, 4J (F-F) ) 6, F2,6]; -104.84 [tt, 1F, 4J (F-F) ) 6, 3J (F-H) )
6, F4]. MS/CI-NH3 (m/z): 231 ([M + H]+).
1
2,3,6-C6H2F 3CHdNCH2CH2NMe2 (2b). H NMR (CDCl3):
δ 2.31 [s, 6H, Me]; 2.68 [t, 2H, 3J (Hd-He) ) 7, Hd]; 3.81 [t, 2H,
3J (Hd-He) ) 7, He]; {6.87 [m, 1H, J (H-F) ) 9, J (H-F) ) 4,
J (H-H) ) 2], 7.17 [m, 1H, H], aromatics}; 8.49 [s, 1H, Hf].
3
5
19F NMR (CDCl3): δ -142.73 [m, 1F, J (F2-F3) ) 19, J (F6-
F3) ) 15, 3J (H4-F3) ) 10, 4J (H5-F3) ) 4, F3]; -137.96 [dd,
1F, 3J (F3-F2) ) 19, 4J (F2-F6) ) 9, F2]; -119.91 [m, 1F, 5J (F6-
F3) ) 15, J (F6-F2) ) 10, J (F6-H5) ) 5, F6]. MS/CI-NH3 (m/
4
3
z): 231 ([M + H]+).
1
2,3,4-C6H2F 3CHdNCH2CH2NMe2 (2c). H NMR (CDCl3):
δ 2.31 [s, 6H, Me]; 2.65 [t, 2H, 3J (Hd-He) ) 7, Hd]; 3.77 [t, 2H,
3J (Hd-He) ) 7, He]; {7.01 [m, 1H]; 7.74 [m, 1H], aromatics};
Exp er im en ta l Deta ils
8.51 [s, 1H, Hf]. 19F NMR (CDCl3): δ -167.60 [td, 1F, J (F4-
3
F3) ) 3J (F2-F3) ) 18, 4J (F3-H5) ) 6, F3]; -149.67 [m, 1F,
1H and 31P{1H} NMR spectra were recorded by using Varian
Gemini 200 (1H, 200 MHz), Varian 500 (1H-1H COSY, 500
MHz), Bruker 250 (31P, 101.25 MHz), and Varian Unity-300
(22) Scott, J . D.; Puddephatt, R. J . Organometallics 1983, 2, 1643.

Activation of C-F and C-H Bonds by Platinum
Organometallics, Vol. 16, No. 6, 1997 1239
4
3J (F3-F4) ) 18, J (F2-F4) ) 3J (F4-H5) ) 9, F4]; -137.54 [dd,
2J (H-H) ) 19, 3J (H-H) ) 11], Hf}; 4.62 [d, 1H, 3J (H-H) )
11, Hi]; 5.27 [br, 1H, Hh]; {6.57 [m, 1H]; 6.63 [m, 1H],
aromatics}. 19F NMR (CDCl3): δ -105.72 [t, 1F, J ) 8, F2],
-122.44 [m, 1F, F5], -235.40 [s, 1F, F6].
Compounds 5 were obtained by adding a solution of 3.4 ×
10-4 mol of the corresponding imine in acetone (10 mL) to a
solution of 100 mg (1.7 × 10-4 mol) of compound 1 in acetone.
The mixture was stirred for 16 h, and the solvent was removed
under vacuum. The residue was washed with hexane to yield
red solids, which were filtered, washed with hexane, and dried
under vacuum.
[P tMe{Me2NCH2CH2NdCH(2,3,4-C6HF 3)}] (5c). Yield:
130 mg (85%). Anal. Calcd for C12H15F3N2Pt: C, 32.81; H,
3.44; N, 6.38. Found: C, 32.12; H, 3.40; N, 6.11. FAB(+)
(NBA, m/z): 423 ([M - CH3]+), 439 ([M]+), 578 ([M - CH3
+NBA+]). UV-vis (acetone): λ 415 nm (ꢀ ) 1169 M-1 cm-1),
λ 335 nm (ꢀ ) 1693 M-1 cm-1). 1H NMR (acetone-d6): δ 0.76
[s, 3H, 2J (H-Pt) ) 79, Mea]; 2.76 [s, 6H, 3J (H-Pt) ) 23, Mec];
3.21 [t, 2H, 3J (H-Pt) ) 15, 3J (Hd-He) ) 6, Hd]; 4.20 [t, 2H,
1F, 3J (F2-F3) ) 18, 4J (F2-F4) ) 9, F2]. MS/CI-NH3 (m/z): 231
([M + H]+).
1
2,4,5-C6H2F 3CHdNCH2CH2NMe2 (2d ). H NMR (CDCl3):
δ 2.31 [s, 6H, Me]; 2.64 [t, 2H, J (Hd-He) ) 7, Hd]; 3.75 [td,
3
2H, J (Hd-He) ) 7, J (He-Hf) ) 1, He]; {6.93 [td, 1H, J (H-
3
4
3
F) ) 10, 4J (H-F) ) 4]; 7.81 [m, 1H, 3J (H-F) ) 10], aromatics};
8.49 [t, 1H, J (He-Hf) ) 1, Hf]. 19F NMR (CDCl3): δ -142.62
4
[m, 1F, F5]; -130.10 [m, 1F, 3J (F4-F5) ) 21, 4J (F2-F4) )
3J (F4-H3) ) 10, 4J (F4-H6) ) 4, F4]; -124.45 [m, 1F, F2]. MS/
CI-NH3 (m/z): 231 ([M + H]+).
1
3,4,5-C6H2F 3CHdNCH2CH2NMe2 (2e). H NMR (CDCl3):
δ 2.31 [s, 6H, Me]; 2.64 [t, 2H, 3J (Hd-He) ) 7, Hd]; 3.71 [t, 2H,
3J (Hd-He) ) 7, He]; 7.38 [dd, 2H, J (H-F) ) 8, J (H-F) ) 6,
3
4
aromatics]; 8.18 [s, 1H, Hf]. 19F NMR (CDCl3): δ -157.62 [tt,
3
3
4
4
1F, J (F3-F4) ) J (F5-F4) ) 20, J (F4-H2) ) J (F4-H6) ) 6,
F4]; -134.41 [dd, 2F, 3J (F-F) ) 20, 3J (F-H) ) 8, F3, F5]. MS/
CI-NH3 (m/z): 231 ([M + H]+).
Compounds 3 were characterized by the following proce-
dure: a 20.0 mg (0.035 mmol) amount of complex 1 and 0.07
mmol of the corresponding imine were dissolved in 0.6 mL of
acetone-d6, and the 1H NMR spectrum was recorded.
[P t Me2{Me2NCH 2CH 2NdCH (2,4,6-C6H 2F 3)}] (3a ). 1H
3
4
3J (H-H) ) 6, He]; 6.95 [m, 1H, J (H5-F4) ) 11, J (H5-F3) )
7, J (H5-F2) ) 2, aromatic]; 8.98 [s, 1H, J (H-Pt) ) 62, Hf].
5
3
19F NMR (acetone-d6): δ -169.81 [td, 1F, J (F3-F4) ) 3J (F3-
3
F2) ) 20, J (F3-H5) ) 7, F3]; -135.69 [m, 1F, J (F-Pt) ) 76,
4
4
3J (F2-F3) ) 20, J (F2-F4) ) 6, F2]; -128.58 [m, 1F, J (F-Pt)
4
4
NMR (acetone-d6): δ -0.21 [s, 3H, J (H-Pt) ) 92, Meb]; 0.35
2
) 80, J (F4-F3) ) 20, J (F4-H5) ) 11, J (F2-F4) ) 6, F4].
[P tMe{Me2NCH2CH2NdCH(2,4,5-C6HF 3)}] (5d ). Yield
120 mg (78%). Anal. Calcd for C12H15F3N2Pt: C, 32.81; H,
3.44; N, 6.38. Found: C, 33.24; H, 3.44; N, 6.32. FAB(+)
(NBA, m/z): 420 ([M - F]+), 423 ([M - CH3]+), 439 ([M]+).
UV-vis (acetone): λ 409 nm (ꢀ ) 2822 M-1 cm-1), λ 335 nm (ꢀ
) 3055 M-1 cm-1). 1H NMR (acetone-d6): δ 1.07 [d, 3H, 2J (H-
3
3
4
[s, 3H, J (H-Pt) ) 85, Mea]; 9.17 [s, 1H, J (H-Pt) ) 52, Hf].
2
3
[P t Me2{Me2NCH 2CH 2NdCH (2,3,6-C6H 2F 3)}] (3b ). 1H
NMR (acetone-d6): δ -0.22 [s, 3H, J (H-Pt) ) 92, Meb]; 0.36
2
[s, 3H, J (H-Pt) ) 85, Mea]; 9.27 [s, 1H, J (H-Pt) ) 53, Hf].
2
3
[P t Me2{Me2NCH 2CH 2NdCH (2,3,4-C6H 2F 3)}] (3c). 1H
NMR (acetone-d6): δ -0.04 [s, 3H, J (H-Pt) ) 92, Meb]; 0.43
2
[s, 3H, J (H-Pt) ) 85, Mea]; 9.34 [s, 1H, J (H-Pt) ) 44, Hf].
2
3
Pt) ) 77, J (H-F) ) 4, Mea]; 2.78 [s, 6H, J (H-Pt) ) 25, Mec];
3
[P t Me2{Me2NCH 2CH 2NdCH (2,4,5-C6H 2F 3)}] (3d ). 1H
3.24 [t, 2H, 3J (H-Pt) ) 15, 3J (H-H) ) 6, Hd]; 4.14 [t, 2H,
NMR (acetone-d6): δ -0.12 [s, 3H, J (H-Pt) ) 92, Meb]; 0.32
2
3J (H-H) ) 6, He]; 6.62 [m, 1H, aromatic]; 9.06 [s, 1H, J (H-
3
[s, 3H, J (H-Pt) ) 85, Mea]; 9.25 [s, 1H, J (H-Pt) ) 42, Hf].
[P t Me2{Me2NCH 2CH 2NdCH (3,4,5-C6H 2F 3)}] (3e). 1H
NMR (acetone-d6): δ 0.01 [s, 3H, 2J (H-Pt) ) 92, Meb]; 0.04
[s, 3H, 2J (H-Pt) ) 85, Mea]; 2.72 [s, 6H, 3J (H-Pt) ) 22, Mec];
3.67 [t, 2H, 3J (Hd-He) ) 6, Hd]; 4.06 [t, 2H, 3J (Hd-He) ) 6,
2
3
Pt) ) 62, Hf]. 19F NMR (acetone-d6): δ -132.3 [td, 1F, J (F-
3
Pt) ) 195, 3J (F4-F5) ) 5J (F5-F2) ) 20, 4J (F5-H3) ) 6, F5];
4
3
3
-130.8 [dt, 1F, J (F-Pt) ) 122, J (F4-F5) ) 20, J (F4-H3) )
4J (F4-F2) ) 6, F4]; -120.95 [m, 1F, J (F-Pt) ) 55, F2].
4
He]; {7.54 [dd, 1H, J (H-F) ) 7, J (H-F) ) 7]; 8.48 [dd, 1H,
3J (H-F) ) 9, 4J (H-F) ) 7], aromatics}; 9.16 [s, 1H, 3J (H-Pt)
) 44, Hf].
3
4
[P tMe{Me2NCH2CH2NdCH(3,4,5-C6HF 3)}] (5e). Yield:
130 mg (85%). Anal. Calcd for C12H15F3N2Pt: C, 32.81; H,
3.44; N, 6.38. Found: C, 33.24; H, 3.44; N, 6.32. FAB(+)
(NBA, m/z): 420 ([M - F]+), 423 ([M - CH3]+), 439 ([M]+),
578 ([M - CH3 + NBA+]). UV-vis (acetone): λ 410 nm (ꢀ )
1893 M-1 cm-1), λ 334 nm (ꢀ ) 2184 M-1 cm-1). 1H NMR
Compounds 4 were obtained by adding a solution of 3.4 ×
10-4 mol of the corresponding imine in acetone (10 mL) to a
solution of 100 mg (1.7 × 10-4 mol) of compound 1 in acetone.
The mixture was stirred for 16 h, and the resulting white
crystals were filtered and dried under vacuum.
2
(acetone-d6): δ 1.04 [d, 3H, J (H-Pt) ) 77, J (H-F) ) 4, Mea];
2.75 [s, 6H, 3J (H-Pt) ) 25, Mec]; 3.20 [t, 2H, 3J (H-H) ) 6,
Hd]; 4.11 [t, 2H, 3J (H-H) ) 6, He]; 7.2 [m, 1H, aromatic]; 8.87
[P t F M e 2 {M e 2 N C H 2 C H 2 N H C H (C H 2 C O M e )(2,4-C 6 -
H2F 2)}] (4a ). Yield: 150 mg (84%). Anal. Calcd for C16H25
3
[s, 1H, J (H-Pt) ) 61, Hf]. 19F NMR (acetone-d6): δ -155.0
-
[m, 1F, 4J (F-Pt) ) 100, 3J (F5-F4) ) 24, 3J (F3-F4) ) 18, 4J (F4-
F3N2OPt. C, 37.43; H, 4.91; N, 5.45. Found: C, 37.12; H, 4.94;
N, 5.26. FAB(+) (NBA, m/z): 479 ([M - CH3 - F]+). IR: ν-
(NsH) 3086 cm-1, ν(CdO) 1725 cm-1. 1H NMR (CDCl3): δ 1.03
[s, 3H, 2J (H-Pt) ) 67, Meb]; 1.05 [s, 3H, 2J (H-Pt) ) 66, Mea];
{2.13 [s, 3H, 3J (H-Pt) ) 17]; 2.21 [s, 3H], Mec}; {2.44 [td, 1H,
2J (H-H) ) 12, 3J (H-H) ) 2]; 2.49 [td, 1H, 2J (H-H) ) 12,
3J (H-H) ) 2], 3.26 [m, 1H]; 3.62 [m, 1H], Hd, He}; 2.55 [d,
3
3
H2) ) 7, F4]; -143.7 [m, 1F, J (F3-F4) ) 18, J (F3-H2) ) 10,
4J (F3-F5) ) 4, F3]; -118.5 [d, 1F, J (F-Pt) ) 198, J (F5-F4)
3
3
) 24, F5].
Compounds 6 were prepared by adding an excess of methyl
iodide (0.1 mL) to a solution of 30 mg (0.068 mmol) of the
corresponding compound 5 in acetone. The mixtures were
stirred for 15 min, and the solvent was removed under vacuum
to yield light yellow solids.
3H, J (H-H) ) 2, Meg]; {2.89 [dd, 1H, J (H-H) ) 19, J (H-
H) ) 2]; 2.97 [dd, 1H, 2J (H-H) ) 19, 3J (H-H) ) 10], Hf}; 4.51
[d, 1H, 3J (H-H) ) 10, Hi]; 5.0 [br, 1H, Hh]; {6.47 [ddd, 1H,
J (H-F) ) 11, J (H-F) ) 9, J (H-H) ) 2]; 6.66 [dd, 1H, J (H-
Pt) ) 57, J (H-F) ) 9], aromatics}.
2
3
[P tIMe2{Me2NCH2CH2NdCH(2,3,4-C6HF 3)}] (6c). Yield:
30 mg (76%). Anal. Calcd for C13H18F3IN2Pt: C, 26.86; H,
3.12; N, 4.82. Found: C, 27.23; H, 3.23; N, 4.80. 1H NMR
2
(acetone-d6): δ 0.80 [s, 3H, J (H-Pt) ) 71, Meb]; 1.13 [s, 3H,
[P t F M e 2 {M e 2 N C H 2 C H 2 N H C H (C H 2 C O M e )(2,5-C 6 -
H2F 2)}] (4b). Yield 140mg (78%). Anal. Calcd for C16H25
2J (H-Pt) ) 64, Mea]; {2.68 [s, 3H, 3J (H-Pt) ) 18], 3.20 [s,
3H, 3J (H-Pt) ) 13] Mec}; {4.18 [m], 4.30 [m] Hd, He}; 6.84
[m, 1H, H5]; 8.96 [s, 1H, 3J (H-Pt) ) 50, Hf]. 19F NMR
-
F3N2OPt: C, 37.43; H, 4.91; N, 5.45. Found: C, 37.09; H, 5.00;
N, 5.31. FAB(+) (NBA, m/z): 442 ([M - CH3 - CH2COCH3]+),
464 ([M - 2CH3 - F]+), 479 ([M - CH3 - F]+), 483 ([M -
5
3
(acetone-d6): δ -166.49 [td, 1F, J (F-Pt) ) 12, J (F2-F3) )
3J (F4-F3) ) 19, 4J (F3-H5) ) 8, F3]; -133.03 [dd, 1F, 4J (F-
2CH3]+), 494 ([M - F]+). IR: ν(NsH) ) 3080 cm-1, ν(CdO) )
Pt) ) 42, J (F2-F3) ) 19, J (F2-F4) ) 8, F2]; -125.06 [dt, 1F,
3
4
1725 cm-1
.
1H NMR (CDCl3): δ 1.12 [d, 3H, J (H-Pt) ) 70,
2
4J (F-Pt) ) 47, 3J (F4-F3) ) 19, 3J (F2-F4) ) J (F4-H5) ) 8,
4
J (H-F) ) 8, Meb]; 1.42 [dd, 3H, J (H-Pt) ) 63, J (H-F) ) 9,
2
F4].
J (H-F) ) 8, Mea]; {2.22 [s, 3H, J (H-Pt) ) 18]; 2.25 [s, 3H],
3
Mec}; {2.44 [m, 2H]; 3.22 [dd, 1H, J (H-H) ) 13, J (H-H) )
2]; 3.59 [m, 1H], Hd, He}; 2.54 [d, 3H, J (H-H) ) 2, Meg];
{2.89 [dd, 1H, 2J (H-H) ) 19, 3J (H-H) ) 1]; 3.08 [dd, 1H,
[P tIMe2{Me2NCH2CH2NdCH(2,4,5-C6HF 3)}] (6d ). Yield:
25 mg (63%). Anal. Calcd for C13H18F3IN2Pt: C, 26.86; H,
3.12; N, 4.82. Found: C, 27.21; H, 3.19; N, 4.84. 1H NMR
2
3

1240 Organometallics, Vol. 16, No. 6, 1997
Lo´pez et al.
2
(acetone-d6): δ 0.90 [s, 3H, J (H-Pt) ) 71, Meb]; 1.51 [d, 3H,
Ta ble 4. Cr ysta llogr a p h ic Da ta a n d Deta ils of th e
Refin em en ts for Com p ou n d s 4a a n d 5c
2J (H-Pt) ) 63, J (H-F) ) 5, Mea]; {2.67 [s, 3H, 3J (H-Pt) )
20], 3.18 [s, 3H, 3J (H-Pt) ) 15] Mec}: {3.3 [m, 1H], 4.2 [m,
1H], 4.28 [m, 2H], Hd, He}; 6.89 [m, 1H, H3]; 9.03 [d, 1H, 3J (H-
Pt) ) 47, J (H-H) ) 1, Hf]. 19F NMR (acetone-d6): δ -129.14
[m, 1F, 5J (F-Pt) ) 84, 3J (F5-F4) ) 23, 5J (F2-F5) ) 17, 4J (F5-
formula
4a
5c
formula
fw
C16H25F3N2OPt
513.47
C12H15F3N2Pt
439.35
cryst syst
space group
a, Å
b, Å
c, Å
triclinic
P1h
monoclinic
P21/a
8.127(4)
16.4270(12)
10.2377(9)
90
101.12
90
1341.1(7)
2.175
4
H3) ) 5, F5]; -122.09 [m, 1F, J (F-Pt) ) 73, J (F5-F4) ) 23,
4
3
4J (F2-F4) ) 11, J (F3-H3) ) 5, F4]; -112.86 [m, 1F, J (F-Pt)
3
4
8.068(3)
10.2740(8)
12.0189(12)
114.170(8)
104.22(2)
90.893(13)
873.4(3)
1.952
) 32, J (F2-F5) ) 17, J (F2-F4) ) 10, J (F2-H3) ) 5, F2].
5
4
3
[P tIMe2{Me2NCH2CH2NdCH(3,4,5-C6HF 3)}] (6e). Yield:
25 mg (63%). Anal. Calcd for C13H18F3IN2Pt: C, 26.86; H,
3.12; N, 4.82. Found: C, 27.20; H, 3.25; N, 4.92. 1H NMR
R, deg
â, deg
γ, deg
V, Å3
2
(acetone-d6): δ 0.89 [s, 3H, J (H-Pt) ) 70, Meb]; 1.49 [d, 3H,
Dc, g cm-3
Z
2J (H-Pt) ) 63, J (H-F) ) 5, Mea]; {2.66 [s, 3H, 3J (H-Pt) )
19], 3.17 [s, 3H, 3J (H-Pt) ) 15] Mec}; {3.2 [m, 1H], 4.2 [m,
1H], 4.27 [m, 2H], Hd, He}; 7.47 [m, 1H, 3J (F3-H2) ) 10, 4J (F4-
2
F(000)
496
824
cryst size, mm3
λ(Mo KR), Å
T, K
0.1 × 0.1 × 0.1
0.710 69
293(2)
0.1 × 0.1 × 0.2
0.710 69
293(2)
H2) ) 7, H2]; 8.86 [d, 1H, 3J (H-Pt) ) 51, J (H-H) ) 1, Hf]. 19
F
NMR (acetone-d6): δ -151.51 [m, 1F, J (F-Pt) ) 57, J (F5-
5
3
F4) ) 23, J (F4-F3) ) 19, J (F4-H) ) 7, F4]; -140.42 [m, 1F,
3
4
no. of rflns collected
R
5074
0.032
0.0742
4202
0.047
0.1132
3J (F3-F4) ) 19, J (F3-H2) ) 10, J (F3-F5) ) 5, F3]; -121.25
3
4
Rw(F2)
[m, 1F, 4J (F-Pt) ) 84, 3J (F4-F5) ) 22, 4J (F3-F5) ) J (H2-
5
no. of refined params
max shift/esd
max and min
diff peaks, e Å-3
217
0.49
174
0.00
5
F5) ) 5, J (F5-Hf) ) 1, F5].
+0.984 and -0.935
+0.631 and -0.612
Compounds 7 were obtained by adding 1 equiv (7c) or 2
equiv (7d , 7e) of PPh3 to a solution of 50 mg (0.114 mol) of the
corresponding compound 5 in acetone. The mixture was
stirred for 30 min, and the solvent was removed under vacuum.
The residue was washed with hexane to yield orange (7c) or
white (7d , 7e) solids, which were filtered, washed with hexane,
and dried under vacuum.
scan technique. For 4a , 5074 reflections were measured in
the range 1.93° < θ < 29.96°; 4562 were assumed as observed,
applying the condition I > 2σ(I). For 5c, 4202 reflections were
measured in the range 2.03° < θ < 29.97°; 3905 were
nonequivalent by symmetry, and 2935 were assumed as
observed, applying the condition I > 2σ(I). Absorption cor-
rection was made from ψ scans;23 maximum and minimum
transmission factors were 0.894 and 0.475 for 4a and 0.763
and 0.421 for 5c. Further details are given in Table 4.
[P t Me(P P h 3){Me2NCH2CH2NdCH(2,3,4-C6HF 3)}] (7c).
Yield: 65 mg (81%). Anal. Calcd for C30H30F3N2PPt: C, 51.35;
H, 4.31; N, 3.99. Found: C, 50.68; H, 4.54; N, 3.63. 1H NMR
(acetone-d6): δ 0.61 [d, 3H, 2J (H-Pt) ) 81, 3J (H-P) ) 7, Mea];
1.79 [t, 2H, J (H-H) ) 6, Hd]; 1.92 [s, 6H, Mec], 3.22 [t, 2H,
3
3J (H-H) ) 6, He]; 7.30-7.73 [16H, aromatic]; 8.89 [s, 1H,
3J (H-Pt) ) 59, Hf]. 19F NMR (acetone-d6): δ -170.96 [td, 1F,
Str u ctu r e Solu tion a n d Refin em en t. The structures
were solved by Patterson Syntheses, using the SHELXS
computer program,24 and refined by the full-matrix least-
squares method, with the SHELX93 computer program.25 The
3J (F3-F2) ) J (F3-F4) ) 18, J (F3-H5) ) 5, F3]; -140.05 [m,
1F, 4J (F-Pt) ) 44, 3J (F2-F3) ) 18, F2]; -132.32 [dd, 1F, 4J (F-
Pt) ) 53, 3J (F4-F3) ) 18, 3J (F4-H5) ) 10, F4]. 31P NMR
(acetone-d6): δ 30.87 [s, J (P-Pt) ) 2385].
3
4
2
2 2
function minimized as ∑w||Fo| - |Fc| | , where w ) [σ2(I) +
(0.1245P)2]-1 for 4a , w ) [σ2(I) + (0.0859P)2 + 0.8780P]-1 for
2
2
5c, and P ) (|Fo| + 2|Fc| )/3. f, f ′, and f ′′ were taken from
ref 26. For 4a , 1 hydrogen atom (H(1)) was located from a
difference synthesis and refined isotropically and 24 hydrogen
atoms were computed and refined with an overall isotropic
temperature factor using a riding model. For 5c, six hydrogen
atoms were located from a difference synthesis and nine
hydrogen atoms were computed and refined with an overall
isotropic temperature factor using a riding model. The final
R factors, the number of refined parameters, and the maxi-
mum and minimum peaks in the final difference synthesis are
given in Table 4.
[P tMe(P P h 3)2{Me2NCH2CH2NdCH(2,4,5-C6HF 3)}] (7d ).
Yield: 80 mg (73%). Anal. Calcd for C48H45F3N2P2Pt: C,
1
59.81; H, 4.70; N, 2.91. Found: C, 59.32; H, 4.70; N, 2.87. H
2
3
NMR (acetone-d6): δ 0.19 [dd, 3H, J (H-Pt) ) 65, J (H-Pb)
) 8, J (H-Pa) ) 6, Mea]; 2.26 [s, 6H, Mec]; 2.54 [t, 2H, J (H-
3
3
H) ) 7, He]; 3.83 [t, 2H, J (H-H) ) 7, Hd]; 6.3 [m, H3]; 7.00-
3
7.55 [m, 30H, aromatic]; 8.89 [d, 1H, J (H-F) ) 1, Hf]. 19F
NMR (acetone-d6): δ -135.88 [m, 1F, 4J (F-Pt) ) 108, 3J (F5-
F4) ) 33, 4J (F4-F2) ) 3J (F4-H3) ) 10, 4J (F4-Pa) ) 4, F4];
-120.32 [m, 1F, F2]; -117.81 [m, 1F, J (F-Pt) ) 470, J (F5-
3
3
F4) ) 33, J (F5-F2) ) 4J (F5-Pa) ) 15, J (F5-H3) ) 6, F5]. 31P
NMR (acetone-d6): δ 25.49 [d, 2J (P-P) ) 15, J (P-Pt) ) 1989,
Pb]; 25.83 [m, J (Pt-Pt) ) 2382, Pa].
5
4
Ack n ow led gm en t. We acknowledge financial sup-
port from the DGICYT (Ministerio de Educacio´n y
Ciencia, Spain) and from the Generalitat de Catalunya.
[P tMe(P P h 3)2{Me2NCH2CH2NdCH(3,4,5-C6HF 3)}] (7e).
Yield: 85 mg (77%). Anal. Calcd for C48H45F3N2P2Pt: C,
1
59.81; H, 4.70; N, 2.91. Found: C, 58.93; H, 4.69; N, 2.84. H
2
3
NMR (acetone-d6): δ 0.20 [dd, 3H, J (H-Pt) ) 65, J (H-Pb)
Su p p or tin g In for m a tion Ava ila ble: Tables giving all
bond lengths and angles, refined and calculated atomic
coordinates, and anisotropic thermal parameters for 4a and
5c (13 pages). Ordering information is given on any current
masthead page.
) 8, J (H-Pa) ) 7, Mea]; 2.18 [s, 6H, Mec]; 2.42 [m, 2H, He];
3
3.68 [m, 2H, Hd]; 7.05-7.43 [m, 31H, aromatic]; 9.20 [d, 1H,
J (H-H) ) 3, Hf]. 19F NMR (acetone-d6): δ -163.05 [m, 1F,
4J (F-Pt) ) 88, J (F5-F4) ) 30, J (F3-F4) ) 19, J (F4-H2) )
3
3
4
7, F4]; -147.05 [m, 1F, F3]; -112.40 [m, 1F, J (F-Pt) ) 415,
3
3J (F5-F4) ) 30, J (F5-Pa) ) 15, J (F5-F3) ) 4, F5]. 31P NMR
4
4
OM960803O
(acetone-d6): δ 25.42 [d, J (P-P) ) 15, J (P-Pt) ) 1907, Pb];
2
26.00 [m, J (P-Pt) ) 2300, Pa].
(23) North, A. C. T.; Phillips, D. C.; Mathews, F. S. Acta Crystallogr.
1968, A24, 351.
(24) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467.
(25) Sheldrick, G. M. SHELX 93: A Computer Program for Crystal
Structure Refinement; University of Gottingen, Gottingen, Germany,
1993.
X-r a y Str u ctu r e An a lysis. Da ta Collection . Prismatic
crystals were selected and mounted on an Enraf-Nonius CAD4
diffractometer. Unit cell parameters were determined from
automatic centering of 25 reflections (12° < θ < 21°) and
refined by least-squares methods. Intensities were collected
with graphite-monochromated Mo KR radiation, using the ω/2θ
(26) International Tables of X-Ray Crystallography; Kynoch Press:
Birmingham, U.K., 1974; Vol. IV, pp 89-100, 149.