Methyl(hydrido)platinum(IV) complexes with flexible tridentate nitrogen-donor ligands

Article abstract of DOI:10.1021/om0206352

The flexible, unsymmetrical triamine ligands NNN = N,N,N′-trimethyl-N′-(2-pyridylmethyl)ethylenediamine (PICO), N-benzyl-N′,N′-dimethyl-N-(2-picolyl)ethylenediamine (BPICO), and N,N′,N″-pentamethyldiethylenetriamine (PMDETA) act as bidentate ligands in fo

Full text of DOI:10.1021/om0206352

Organometallics 2003, 22, 787-796
787
Meth yl(h yd r id o)p la tin u m (IV) Com p lexes w ith F lexible
Tr id en ta te Nitr ogen -Don or Liga n d s
Ernest M. Prokopchuk and Richard J . Puddephatt*
Department of Chemistry, University of Western Ontario, London, Canada N6A 5B7
Received August 6, 2002
The flexible, unsymmetrical triamine ligands NNN ) N,N,N′-trimethyl-N′-(2-pyridyl-
methyl)ethylenediamine (PICO), N-benzyl-N′,N′-dimethyl-N-(2-picolyl)ethylenediamine
(BPICO), and N,N′,N′′-pentamethyldiethylenetriamine (PMDETA) act as bidentate ligands
in forming square-planar dimethylplatinum(II) complexes cis-[PtMe2(NNN)]. These complexes
undergo oxidative addition with MeI to give the platinum(IV) complexes fac-[PtMe3(NNN)]I,
in which the ligand NNN is fac-tridentate in [PtMe3(NNN)]I when NNN ) PICO or BPICO,
but in equilibrium with bidentate NNN in [PtIMe3(NNN)] when NNN ) PMDETA.
Protonation of the complexes cis-[PtMe2(NNN)] gave the corresponding dimethyl(hydrido)-
platinum(IV) complexes, [PtHMe2(NNN)]X (X ) BF4-, CF3SO3-, CF3CO2-), often as a mixture
of isomers whose structures were deduced from the NMR spectra. These hydridoplatinum-
(IV) complexes undergo reductive elimination of methane to give the methylplatinum(II)
complexes [PtMe(NNN)]X, in which NNN is a mer-tridentate ligand, with the rate of reaction
for NNN ) PMDETA > PICO, BPICO. In all cases, H/D exchange experiments indicate
reversibility of the protonation and methyl(hydride) to methane complex steps in the reaction
sequence.
Ch a r t 1a
In tr od u ction
Alkyl(hydrido)platinum(IV) complexes are important
intermediates in several catalytic reactions, most no-
tably in the activation of alkanes by oxidative addition
of C-H bonds to platinum(II) complexes, and so there
has been intense interest in the synthesis and properties
of such complexes.1-8 The first examples of these
complexes, including [PtHXMe2(NN)] (X ) Cl, Br, I; NN
) 2,9-dimethyl-1,10-phenanthroline, 2,2′-bipyridine or
its derivatives; and tmeda ) N,N,N′,N′-tetramethyleth-
ylenediamine, Chart 1), containing bidentate nitrogen-
donor ligands, had limited thermal stability and were
characterized by low-temperature NMR techniques.
(1) Stahl, S. S.; Labinger, J . A.; Bercaw, J . E. Angew. Chem., Int.
Ed. 1998, 37, 2180.
(2) Periana, R. A.; Taube, D. J .; Gamble, S.; Taube, H.; Satoh, T.;
Fujii, H. Science 1998, 280, 560.
(3) (a) Belluco, U.; Giustiniani, M.; Graziani, M. J . Am. Chem. Soc.
1967, 89, 6494. (b) J awad, J . K.; Puddephatt, R. J . J Chem. Soc., Chem.
Commun. 1977, 892. (c) Arnold, D. P.; Bennett, M. A. Inorg. Chem.
1984, 23, 2119.
a
R ) H, Me, t-Bu; X ) Cl, Br, I.
These complexes decomposed easily by reductive
elimination of methane to give the corresponding plati-
num(II) complex [PtXMe(NN)].4 The mechanism of
reductive elimination involves the dissociation of the
ligand X- to generate the cationic, 5-coordinate inter-
mediate [PtHMe2(NN)]+, which then undergoes loss of
methane.1,4 Stable methyl(hydrido)platinum(IV) com-
plexes were formed if there was no easily dissociated
ligand, as in neutral complexes such as [PtHMe3(bu2-
bpy)] (bu2bpy ) 4,4′-di-tert-butyl-2,2′-bipyridine)5 or
[PtHMe2Tp′], where Tp′ ) tris(methylpyrazolyl)borate.6
The cationic complex [PtHMe2(9N3)]+, with the fac-
coordinating ligand 9N3 ) 1,4,7-triazacyclononane, had
thermal stability comparable to that of [PtHMe2Tp′],9
while the complex cation [PtHMe2(BPMA)]+, with the
more flexible tridentate ligand BPMA ) bis(2-pyridyl-
(4) (a) De Felice, V.; De Renzi, A.; Panunzi, A.; Tesauro, D. J .
Organomet. Chem. 1995, 488, C13. (b) Stahl, S. S.; Labinger, J . A.;
Bercaw, J . E. J . Am. Chem. Soc. 1995, 117, 9371; 1996, 118, 5961. (c)
Hill, G. S.; Rendina, L. M.; Puddephatt, R. J . Organometallics 1995,
14, 4966. (d) Wehman-Ooyevaar, I. C. M.; Grove, D. M.; de Vaal, P.;
Dedieu, A.; van Koten, G. Inorg. Chem. 1992, 31, 5484.
(5) Hill, G. S.; Puddephatt, R. J . J . Am. Chem. Soc. 1996, 118, 8745.
(6) (a) O’Reilly, S. A.; White, P. S.; Templeton, J . L. J . Am. Chem.
Soc. 1996, 118, 5684. (b) Canty, A. J .; Dedieu, A.; J in, H.; Milet, A.;
Richmond, M. K. Organometallics 1996, 15, 2845. (c) Reinartz, S.;
White, P. S.; Brookhart, M.; Templeton, J . L. Organometallics 2000,
19, 3854. (d) Iron, M. A.; Lo, C.; Martin, J . M. L.; Keinan, E. J . Am.
Chem. Soc. 2002, 124, 7041.
(7) (a) J enkins, H. A.; Yap, G. P. A.; Puddephatt, R. J . Organome-
tallics 1997, 16, 1946. (b) Hill, G. S.; Puddephatt, R. J . Organometallics
1998, 17, 1478. (c) Fekl, U.; Zahl, A.; van Eldik, R. Organometallics
1999, 18, 4156.
(8) (a) Wick, D. D.; Goldberg, K. I. J . Am. Chem. Soc. 1997, 119,
10235. (b) Holtcamp, M. W.; Labinger, J . A.; Bercaw, J . E. J . Am. Chem.
Soc. 1997, 119, 848. (c) J ohansson, L.; Tilset, M.; Labinger, J . A.;
Bercaw, J . E. J . Am. Chem. Soc. 2000, 122, 10846.
10.1021/om0206352 CCC: $25.00 © 2003 American Chemical Society
Publication on Web 01/10/2003

788 Organometallics, Vol. 22, No. 4, 2003
Prokopchuk and Puddephatt
Sch em e 1. Syn th esis of P la tin u m (II) Com p lexes
Sch em e 2. Tr im eth ylp la tin u m (IV) Com p lexes
methyl)amine (Chart 1), had intermediate thermal
stability and decomposed in solution to give methane
and [PtMe(BPMA)]+ over a period of about 1 day at
room temperature.7 This intermediate thermal stability
allows easy study of further reactions, such as H/D
exchange between the hydrido and methyl ligands and
the mechanism of the reductive elimination of methane.7
Thus it was of interest to study analogous chemistry
with other flexible tridentate nitrogen-donor ligands, to
determine how ligand structure affects the reactivity
and selectivity.
The ligand BPMA ) NH(CH2-2-py)2 contains two
2-picolyl units and a central NH group. The NH group
can cause complications in H/D exchange reactions and
was substituted in the present work by NMe or NCH2-
Ph groups. In addition, one or both of the 2-picolyl
groups in BPMA was replaced by CH2CH2NMe2 groups
to study the relative effects of pyridyl and amine ligands
on the reaction chemistry. The ligands used were Me2-
NCH2CH2N(R)CH2-2-py (PICO, R ) Me; BPICO, R )
CH2Ph) and (Me2NCH2CH2)2NMe (PMDETA), and the
resulting methyl(hydrido)platinum(IV) chemistry is re-
ported below.
dination of the PICO ligand in 1 was determined by the
195Pt satellite spectra of the ligand resonances in the
1H NMR spectrum. Thus, satellite spectra were ob-
served for the o-pyridyl proton at δ(H6) 8.72 ppm
[J (PtH) ) 22 Hz] and for the NMe group at δ 2.69 ppm
[3J (PtH) ) 14 Hz], but not for the NMe2 resonance,
showing that the ligand PICO is coordinated through
the pyridyl and central NMe nitrogen atoms, with the
terminal NMe2 group free (Scheme 1). Complex 2 was
characterized similarly, and the structures of 1 and 2,
with coordinated 2-pyridyl groups and free CH2CH2-
NMe2 groups, clearly show the preference for pyridine
1
over amine coordination at platinum(II). The H NMR
spectrum of [PtMe2(PMDETA)], 3, contained methyl-
platinum resonances at δ 0.17 [2J (PtH) ) 89 Hz] and
0.12 ppm [2J (PtH) ) 87 Hz]. Singlet resonances were
observed at δ 2.55 ppm [3J (PtH) ) 21 Hz] for the
coordinated terminal Me2N groups, at δ 2.60 ppm
[3J (PtH) ) 21 Hz] for the coordinated central MeN
group, and at δ 2.15, with no resolved coupling to 195Pt,
for the uncoordinated Me2N groups. There was no
indication of fluxionality involving intramolecular ni-
trogen ligand substitution for any of these complexes
1-3.
Oxid a tive Ad d ition Rea ction s w ith MeI. The
reactions with methyl iodide are useful as models for
oxidative additions, since the products are thermally
stable and so benchmark spectroscopic data can be
obtained. The products formed are shown in Scheme 2.
The oxidative addition of MeI to complexes 1 or 2 in
acetone or thf solution gave the stable trimethylplati-
num(IV) complexes [PtMe3(PICO)]I, 4, or [PtMe3-
(BPICO)]I, 5, respectively. Consider the NMR spectrum
of complex 4 as an example. Since the ligand fac-PICO
is unsymmetrical, the three methylplatinum groups in
4 are nonequivalent and three methylplatinum reso-
nances were observed in both the 1H and 13C NMR
spectra, as expected. Since 195Pt satellite spectra were
observed for all NMe resonances, it is clear that the
Resu lts a n d Discu ssion
P r epar ation of Dim eth ylplatin u m (II) Com plexes.
The synthetic chemistry is shown in Scheme 1. Reaction
of the appropriate ligand with [PtMe2(µ-SMe2)]2 gave
the corresponding dimethylplatinum(II) complex [PtMe2-
(NNN)] (1, NNN ) PICO; 2, NNN ) BPICO; 3, NNN )
PMDETA) by displacement of the dimethyl sulfide
ligands. The complexes all contain free CH2CH2NMe2
groups and, though they were formed in good yield, all
were easily oxidized in solution and were difficult to
crystallize for purification. In most cases the complexes
were characterized spectroscopically, and were prepared
1
and used in situ for further reaction chemistry. The H
and 13C NMR spectra of 1 each contained two methyl-
platinum resonances at δ(1H) 0.54 [2J (PtH) ) 90 Hz]
and 0.49 ppm [2J (PtH) ) 86 Hz], and at δ(13C) -19.24
[1J (PtC) ) 838 Hz] and -21.35 ppm [1J (PtC) ) 843 Hz],
typical of methylplatinum(II) complexes with methyl
groups trans to nitrogen donors.4-9 The mode of coor-
(9) Prokopchuk, E. M.; J enkins, H. A.; Puddephatt, R. J . Organo-
metallics 1999, 18, 2861.

Methyl(hydrido)platinum(IV) Complexes
Organometallics, Vol. 22, No. 4, 2003 789
Ta ble 1. Selected NOESY NMR Da ta for Com p lexes 3 in Aceton e-d 6
proton
δ (ppm); coupling (Hz)
NOESYa
[PtMe3(PICO)]+, 3
Pt-NMe2, Pt-NMe
Pt-Me (trans-py)
Pt-Me (trans-NMe)
Pt-Me (trans-NMe2)
Pt-NMe2
0.79; 2J (PtH) ) 69
0.95; 2J (PtH) ) 68
0.54; 2J (PtH) ) 69
2.29; 3J (PtH) ) 10
2.59; 3J (PtH) ) 17
2.94; 3J (PtH) ) 16
Pt-NMe2
Pt-NMe
Me2N-CH2CH2-NMe, PtMe (trans-NMe)
Me2N-CH2CH2-NMe, Pt-Me (trans-py)
py-CH2, Me2N-CH2CH2-NMe, Pt-Me (trans-NMe2), Pt-Me (trans-py)
Pt-NMe
[PtHMe2(PICO)]+, 8a
Pt-H
-21.18; 1J (PtH) ) 1438
0.86; 2J (PtH) ) 69
0.97; 2J (PtH) ) 66
2.17; 3J (PtH) ) 9
Pt-Me (trans-py)
Pt-Me (trans-NMe)
Pt-NMe2
Pt-NMe2, Pt-NMe
Pt-NMe2
Me2N-CH2CH2-NMe, PtMe (trans-NMe)
Me2N-CH2CH2-NMe, Pt-Me (trans-py)
py-CH2, Me2N-CH2CH2-NMe
2.48; 3J (PtH) ) 17
3.05; 3J (PtH) ) 19
Pt-NMe
a
Correlation underlined.
Ta ble 2. Selected Bon d Len gth s [Å] a n d An gles
[d eg] for [P tMe3((BP ICO)]I, 5
PICO is tridentate, and it follows that iodide is not
coordinated. It was important to assign the 1H NMR
peaks to specific methylplatinum and methylnitrogen
groups, since complex 4 is a model for the hydridoplati-
num(IV) compounds. The assignments of methylplati-
num resonances could not be made on the basis of
coupling constants since all MePt groups are trans to
nitrogen and so give similar values of 2J (PtH) and
1J (PtC) {δ(MePt) 0.95 [2J (PtH) ) 68 Hz], 0.79 [2J (PtH)
) 69 Hz], 0.54 ppm [2J (PtH) ) 69 Hz]; δ(MePt) -3.90
[1J (PtC) ) 712 Hz], -4.53 [1J (PtC) ) 677 Hz], -7.62
ppm [1J (PtC) ) 674 Hz]}. However, a positive assign-
Pt(1)-C(2)
Pt(1)-C(1)
Pt(1)-N(2)
2.040(6)
2.065(5)
2.219(5)
Pt(1)-C(3)
Pt(1)-N(1)
Pt(1)-N(3)
2.059(6)
2.164(5)
2.247(5)
C(2)-Pt(1)-C(3)
C(3)-Pt(1)-C(1)
C(3)-Pt(1)-N(1)
C(2)-Pt(1)-N(2)
C(1)-Pt(1)-N(2)
C(2)-Pt(1)-N(3)
C(1)-Pt(1)-N(3)
N(2)-Pt(1)-N(3)
86.9(2)
C(2)-Pt(1)-C(1)
C(2)-Pt(1)-N(1)
C(1)-Pt(1)-N(1)
C(3)-Pt(1)-N(2)
N(1)-Pt(1)-N(2)
C(3)-Pt(1)-N(3)
N(1)-Pt(1)-N(3)
86.5(3)
89.1(2)
95.1(2)
99.3(2)
77.6(2)
91.6(2)
92.2(2)
88.1(2)
174.7(2)
95.0(2)
172.5(2)
176.4(2)
96.8(2)
82.0(2)
1
The crystal structure contains well-separated cations
of 5 and iodide ions. The platinum center in 5 has
distorted fac-PtC3N3 coordination. The major distortions
from octahedral geometry arise from the constraints of
the tridentate BPICO ligand, with angles N(1)PtN(2)
) 77.6(2)° and N(2)PtN(3) ) 82.0(2)°. The three plati-
num-nitrogen bond lengths are significantly different
from each other, with the shortest distance being to the
pyridyl nitrogen [PtN(1) ) 2.164(5) Å] and the longest
distance to the dimethylamine nitrogen [PtN(3) ) 2.247-
(5) Å]. The Pt-NMe2 bond appears weak and it is
probably for this reason that the Pt-C distance trans
to NMe2 is shorter at Pt-C(2) ) 2.040(6) Å than the
other two [Pt(C(1) ) 2.065(5) Å, Pt(C3) ) 2.059(6) Å].
The benzyl group of the BPICO ligand is directed away
from the platinum center, so there is no intramolecular
ment of the H NMR resonances was accomplished by
1
analysis of the H NOESY spectrum (Table 1). The CH2
resonances of the ligand were readily identified on the
1
basis of their multiplicity in the H NMR spectrum and
were thus used as the basis for the rest of the peak
assignments. Next, correlation of the NMe resonances
to those of the neighboring CH2 protons in the NOESY
spectrum led to their assignments. In turn, the correla-
tions between the NMe resonances and the nearby PtMe
resonances led to the final assignments (Table 1).
The reaction of CD3I with 1 in acetone-d6 gave the
corresponding complex [PtMe2(CD3)(PICO)]I, 4′. The 1H
NMR spectrum of 4′ showed only two of the three
methyl resonances observed for 4, the missing one
indicating that the site of the CD3 group in 4′ is trans
to the NMe2 group. The spectrum of 4′ was unchanged
over several days in solution, indicating that scrambling
of the methyl groups is a slow process. The isomer of 4′
is that expected based on the usual mechanism of
oxidative addition, since the formation of the new PtCD3
bond will be accompanied by coordination of the free
NMe2 group in the trans position.
The reaction of MeI with complex 2 in acetone or thf
occurred similarly to give [PtMe3(BPICO)]I, 5 (Scheme
2). Again using the 1H NOESY NMR data, the three
methylplatinum groups were assigned at δ 0.90 [2J (PtH)
) 68 Hz, trans to pyridyl], 1.02 [2J (PtH) ) 68 Hz, trans
to NBz], and 0.66 ppm [2J (PtH) ) 69 Hz, trans to NMe2].
The resonance at δ 0.66 was of very low intensity in 5′,
formed by reaction of 2 with CD3I, and no change in
1
the relative peak heights was observed in the H NMR
spectra over several days at room temperature. The
structure of complex 5 was confirmed crystallographi-
cally; a view of the cation is shown in Figure 1 and
selected bond distances and angles are given in Table
2.
F igu r e 1. A view of the molecular structure of [PtMe3-
(BPICO)]+, showing 25% thermal ellipsoids. The hydrogen
atoms are omitted for clarity.

790 Organometallics, Vol. 22, No. 4, 2003
Prokopchuk and Puddephatt
Sch em e 3. Hyd r id o(d im eth yl)p la tin u m (IV)
Com p lexes
with X ) BF4 was the protonation product isolated in
solid form, since reaction of 1 with H[BF4] in THF
solution led to precipitation of 8c[BF4], as essentially a
single isomer. Over the course of 7 days in CD2Cl2
solution at room temperature, the mixtures of cations
8a -c was converted slowly to give 8c (H trans to
pyridyl), which must therefore be the thermodynami-
cally most stable dimethyl(hydrido)platinum(IV) isomer.
However, the isomerization was accompanied by slow
reductive elimination of methane to give the corre-
sponding complex cation 10, as described below. The
reaction of complex 1 with excess acid in acetone
solution gave only isomer 8a (H trans to NMe2), and its
subsequent isomerization to 8b and 8c was very slow
under these conditions. This indicates that 8a is the
product of kinetic control. If a solution containing mostly
8a was neutralized (for example, by addition of 1) or if
<1 equiv of acid was used in the reaction with complex
1, the thermodynamic product 8c was the major product
detected and this was the isomer that precipitated on
reaction of 1 with H[BF4] in THF solution. These
observations show that the isomerization process in-
volves catalysis by free complex 1, perhaps involving
direct proton transfer between platinum centers.
The structural assignments for complexes 8a -c were
made, based on the NOESY 1H NMR spectra, as
described above for complex 3. Thus, the product of
kinetic control, cationic complex 8a , is formed from 1
by addition of a proton with coordination of the Me2N
group in the trans position, as expected and proved by
the NOESY data (Table 1).4 The structure of 8c was
deduced similarly, and it is shown to have the hydride
trans to the pyridyl nitrogen donor. The structure of 8b
is then the isomer with hydride trans to the central MeN
nitrogen donor, and this was confirmed by the NOESY
spectrum of the isomeric mixture containing 8a , 8b, and
8c. It should be noted that 8a -c have similar structures
and considerable overlap of the methylplatinum reso-
nances occurred. However, since reaction conditions
were found that gave 8a and 8c in almost isomerically
pure form, and since mixtures of 8a -c were formed with
a range of compositions, it was still possible to assign
these resonances with confidence.
π-stacking. However, there is an edge-to-face aryl-aryl
interaction between the benzyl and pyridyl rings of
neighboring cations, with a distance of 3.89 Å between
the center of the benzyl ring and the R-proton of the
pyridyl ring (a distance of 5.19 Å between the centers
of the rings), with an angle of 103° between the planes
of the two rings.
Oxidative addition of MeI to complex 3 in acetone or
thf occurred to give a mixture of complexes [PtMe3-
(PMDETA)]I, 6a , and [PtIMe3(PMDETA)], 7, according
to Scheme 2. In this case there is competition between
iodide and one of the NMe2 groups for the sixth
coordination site. The similar reaction of methyl triflate
with 3 gave only [PtMe3(PMDETA)][CF3SO3], 6b, as
expected since triflate is a poor ligand for platinum. The
complex cation [PtMe3(PMDETA)]+, 6, has Cs symmetry
and so gives two methylplatinum resonances in a 2:1
ratio for 6a or 6b. However, complex 7 is unsymmetrical
and gives three MePt resonances. The free NMe2 group
was identified by the presence of closely spaced reso-
nances at δ 2.16 and 2.15, similar to the chemical shift
of the free (diastereotopic) Me2N protons in the precur-
sor complex 2. The ratio of 6a :7 formed in the initial
reaction of 3 with MeI was about 3:2, and a very slow
isomerization of 7 to 6a was then observed. After one
month, approximately 20% of 7 had isomerized to 6a .
These results show that all three ligands can be fac-
tridentate in platinum(IV) complexes but the competi-
tion with iodide shows that PICO and BPICO are more
effective fac-tridentate ligands than PMDETA.
In the solid state, reductive elimination of methane
from 8c[BF4] occurred slowly, going to half completion
in 1.5 months with formation of [PtMe(PICO)][BF4],
10[BF4]. The cationic methylplatinum(II) complex 10
was characterized by its 1H NMR spectrum, which
contained a Pt-Me resonance at δ 0.50 ppm [2J (PtH)
) 79 Hz] and three Pt-NMe resonances at δ 2.61
[2J (PtH) ) 16 Hz], 2.79 [2J (PtH) ) 45 Hz], and 2.93 ppm
[2J (PtH) ) 49 Hz]. If the mixture of cationic complexes
8a -c was prepared in solution in CD2Cl2 at room
temperature, reductive elimination of methane typically
occurred over the course of 2 weeks at room temperature
to give complex 10, and the rate was similar for all
anions studied. The reductive elimination of methane
from initially pure 8c[BF4] dissolved in acetone-d6
required 4 weeks for completion but, in the presence of
free H[BF4], both the isomerization to give 8a [BF4] and
8b[BF4] and the reductive elimination of methane were
inhibited. The reductive elimination from 8c[BF4] was
catalyzed modestly by the product 10[BF4]. Thus, for a
sample containing initially an equimolar mixture of
P r oton a tion Rea ction s: (a ) Rea ction s of Com -
p lexes 1 a n d 2 w ith H+ a n d D+. The reaction of
complex 1 at room temperature with 1 equiv of acid HX
(X- ) CF3SO3-, CF3CO2-, BF4-) in acetone or dichlo-
romethane solution generally gave a mixture of all three
possible isomers of the corresponding cationic complex
[PtMe2H(PICO)]+, 8a -c (Scheme 3). Only in the case

Methyl(hydrido)platinum(IV) Complexes
Organometallics, Vol. 22, No. 4, 2003 791
Sch em e 4. Meth a n e Com p lexes a n d H/D Exch a n ge
F igu r e 2. 1H NMR spectrum following the reaction of
[PtMe2(PICO)] with CF3SO3D in CD3OD, showing deute-
rium incorporation into the methane and the remaining
methylplatinum group of the product [PtMe(PICO)]+.
environment are faster than the methane dissociation
(Scheme 4). Scheme 4 is simplified since it does not show
the isomers of 8 (Scheme 3), which will lead to scram-
bling of partially deuterated methyl groups, and it
shows only the first stages of H/D exchange. It follows
that repetition of the steps leading from 1 to 1* or 8a
to 8a ** in Scheme 4 will lead to multiple H/D exchange.
Scheme 4 also shows how the proposed intermediate
methane complex can be formed with methane trans to
NR (A) or trans to pyridyl (B). Reversibility of the
methane complex with the hydrido(methyl)platinum-
(IV) complex is intuitively more likely for A, since
intramolecular displacement by the free NMe2 group is
not possible while such displacement is possible for B
(Scheme 4). Once the reductive elimination to give
methane and 10 was complete, no further H/D exchange
into the methane or into the methylplatinum group of
10 was observed. Also, the isolated complex 10[CF3SO3],
when dissolved in CD3OD, did not incorporate deute-
rium into the CH3Pt group and did not catalyze H/D
exchange of added CH4. Clearly then, there is no easy
route back to a methane complex from 10.
8c[BF4] and 10[BF4], reductive elimination of methane
from 8c was complete in 8 days. Since excess acid
destroys complex 10 by cleavage of the methylplatinum-
(II) bond, the autocatalysis is not observed in the
presence of excess acid and 8c is stable under these
conditions for several weeks in solution at room tem-
perature. The reaction of 10 with triflic acid was studied
The complex 10, as the triflate salt, was structurally
characterized; details are given in Figure 3 and Table
3. The structure is very similar to that of the BPICO
analogue 11 as discussed below.
1
separately by monitoring at low temperature, using H
NMR. At -80 °C there was no reaction, but reaction
occurred at -60 °C with formation of methane. No
intermediate hydridoplatinum(IV) complex was detected
so it is not determined if the methane formation involves
oxidative addition/reductive elimination or direct pro-
tonolysis.
The protonation of complex 2 occurred in a similar
way to that of 1. Thus, three isomers of [PtMe2H-
-
-
-
(BPICO)]X (X ) CF3SO3 (9a ), CF3CO2 (9b), BF4
(9c)), were observed (Scheme 3). The reaction of 2 with
excess acid gave the kinetic isomer 9a , but less selec-
tively (ca. 60% yield) than with 1 (ca. 90% yield). This
isomer 9a has a hydride resonance at δ -20.99 ppm
[1J (PtH) ) 1435 Hz], and methylplatinum resonances
at δ 1.05 [2J (PtH) ) 66 Hz] and 1.01 ppm [1J (PtH) )
68 Hz], and the NOESY NMR confirmed that the
hydride was trans to NMe2. The isomerization of 9a to
9c was complete in one week, even in the presence of
excess acid, and so was faster than the corresponding
reaction of 8a . The thermodynamically most stable
isomer 9c could be prepared by using <1 equiv of acid
The reaction of complex 1 in methanol-d4 with CF3-
SO3D allowed the observation of H/D exchange (Scheme
4). The methane formed contained the isotopomers CH4,
1
CH3D, CH2D2, and CHD3 detectable by H NMR spec-
troscopy. Furthermore, the PtMe region of the 1H NMR
spectrum showed deuterium incorporation into the
methylplatinum groups of all cationic methylplatinum
complexes 8a , 8b, 8c, and 10 present during the
reaction. Figure 2 shows the presence of PtCH3, PtCH2D,
and PtCHD2 groups in the product 10. These observa-
tions indicate that exchanges between isomers of 8 and
a methane complex [PtMe(CH3D)(PICO)]+, probably
having a bidentate PICO ligand,10 and between the
hydride(deuteride) ligand in 8 and the deuterium rich
(10) The role of ligand dissociation in such reactions has been widely
discussed.1-9 See also: Puddephatt, R. J . Angew. Chem., Int. Ed. 2002,
41, 261.

792 Organometallics, Vol. 22, No. 4, 2003
Prokopchuk and Puddephatt
F igu r e 3. A view of the molecular structure of [PtMe-
(PICO)]+, showing 25% thermal ellipsoids. The hydrogen
atoms are omitted for clarity.
F igu r e 4. A view of the molecular structure of [PtMe-
(BPICO)]+, showing 25% thermal ellipsoids. The hydrogen
atoms are omitted for clarity.
Ta ble 3. Selected Bon d Len gth s [Å] a n d An gles
[d eg] for [P tMe(P ICO)]CF 3SO3, 9
Ta ble 4. Selected Bon d Len gth s [Å] a n d An gles
[d eg] for [P tMe(BP ICO)]CF 3SO3, 11
Pt(1)-C(15)
Pt(1)-N(1)
Pt(1)-N(12)
Pt(1)-N(8)
2.035(8)
2.004(8)
2.045(8)
2.119(7)
Pt(2)-C(35)
Pt(2)-N(21)
Pt(2)-N(32)
Pt(2)-N(28)
2.037(8)
2.013(7)
2.078(9)
2.119(7)
Pt(1)-C(1)
Pt(1)-N(1)
Pt(1)-N(2)
Pt(1)-N(3)
2.039(6)
2.004(6)
2.127(5)
2.064(6)
Pt(2)-C(19)
Pt(2)-N(4)
Pt(2)-N(5)
Pt(2)-N(6)
2.042(7)
2.013(6)
2.130(5)
2.060(7)
N(1)-Pt(1)-C(15)
N(1)-Pt(1)-N(12)
C(15)-Pt(1)-N(12)
N(1)-Pt(1)-N(8)
C(15)-Pt(1)-N(8)
N(12)-Pt(1)-N(8)
98.2(3) N(21)-Pt(2)-C(35)
97.9(3)
N(1)-Pt(1)-C(1)
N(1)-Pt(1)-N(3)
C(1)-Pt(1)-N(3)
N(1)-Pt(1)-N(2)
C(1)-Pt(1)-N(2)
N(3)-Pt(1)-N(2)
97.3(3)
167.9(2)
94.1(3)
81.1(2)
177.8(3)
87.4(2)
N(4)-Pt(2)-C(19)
N(4)-Pt(2)-N(6)
C(19)-Pt(2)-N(6)
N(4)-Pt(2)-N(5)
C(19)-Pt(2)-N(5)
N(6)-Pt(2)-N(5)
96.2(3)
167.3(2)
95.9(3)
81.2(2)
176.7(3)
86.5(2)
166.0(3) N(21)-Pt(2)-N(32) 167.2(3)
95.2(4) C(35)-Pt(2)-N(32)
80.8(3) N(21)-Pt(2)-N(28)
94.0(3)
81.2(3)
179.1(4) C(35)-Pt(2)-N(28) 179.1(3)
85.8(3) N(32)-Pt(2)-N(28)
86.9(3)
in the protonation reaction. This isomer 9c was identi-
fied by the hydride resonance at δ -20.65 ppm [1J (PtH)
) 1412 Hz], and by methylplatinum resonances at δ
1.04 [2J (PtH) ) 67 Hz] and 0.65 ppm [2J (PtH) ) 67 Hz].
The third isomer 9b was observed as a minor species
during the isomerization process, and was characterized
by a hydride resonance at δ -21.05 ppm [1J (PtH) )
1440 Hz] and methylplatinum resonances at δ 1.01
[2J (PtH) ) 68 Hz] and 0.65 ppm [2J (PtH) ) 67 Hz].
methyl, the shortest is Pt-N(pyridyl), and the Pt-NMe2
distance is intermediate (Table 4).
The H/D exchange that occurred on reaction of
complex 2 with CF3SO3D in CD3OD was very similar
to those described for complex 1, and can be fully
explained by the reaction sequence of Scheme 4. How-
ever, the reaction of complex 11 with CF3SO3D in CD3-
OD gave only [Pt(CF3SO3)(BPICO)]CF3SO3 and CH3D,
a clear indication that methane loss is irreversible in
this case.
The reductive elimination of methane from 9 to give
-
[PtMe(BPICO)]X (X ) CF3SO3-, CF3CO2-, BF4 (11),
(b) Rea ction of Com p lex 3 w ith H+ a n d D+.
Reaction of [PtMe2(PMDETA)], 3, in acetone-d6 solution
with 1 equiv of triflic acid at -78 °C gave a mixture of
two cationic dimethylhydridoplatinum(IV) complexes in
a 1:3 ratio, characterized as 12 and 13[CF3SO3] (Scheme
5), but at -50 °C only 13[CF3SO3] was present, as
monitored by 1H NMR spectroscopy. On warming to -10
°C, loss of methane occurred with formation of the
methylplatinum(II) complex 14[CF3SO3] (Scheme 5).
The hydrido(dimethyl)platinum(IV) complex 13 was
occurred in a similar way as for the conversion of 8 to
10. Addition of a second equivalent of triflic acid to 11
led to cleavage of the methylplatinum group with
formation of methane and [Pt(CF3SO3)(BPICO)]CF3SO3.
No intermediate hydrido complex was detected when
this reaction was monitored by low-temperature NMR
so the mechanism is not known. Complex 11, as the
triflate salt, was structurally characterized; the struc-
ture is shown in Figure 4 and selected bond distances
and angles are given in Table 4. There are two inde-
pendent cations and anions in the unit cell but they
have very similar structures (Table 4). Each complex
has distorted square-planar stereochemistry with mer-
tridentate BPICO ligand. The greatest angle distortions
for Pt(1) are N(1)Pt(1)N(3) ) 81.1(2)° and N(1)Pt(1)N(3)
) 167.9(2)°, arising from geometrical constraints of the
BPICO ligand. The pattern of Pt-N distances is differ-
ent from that in the trimethylplatinum(IV) complex 5,
which has the fac-tridentate ligand with all nitrogen
atoms trans to methyl, in which the Pt-NMe2 bond was
clearly weakest (Figure 1, Table 2). In complex 11, the
longest PtN distance is Pt-NBz, which is trans to
1
readily characterized by its H NMR spectrum at -50
°C. The hydride resonance was at δ -22.60 ppm, with
1J (PtH) ) 1484 Hz, and there were two equal intensity
methylplatinum(IV) resonances at δ 0.80 [2J (PtH) ) 68
Hz] and 0.77 ppm [2J (PtH) ) 64 Hz]. These data define
the stereochemistry as 13 (Scheme 5) since the other
possible isomer with hydride trans to the NMe group
would give only one methylplatinum resonance. The
second isomer was formed as a minor component only
at very low temperature, and its characterization is less
certain. At -80 °C, the hydride resonance was at δ
-22.24 ppm [1J (PtH) ) 1474 Hz]. There was a meth-
ylplatinum resonance at δ 0.76 ppm [2J (PtH) ) 66 Hz],

Methyl(hydrido)platinum(IV) Complexes
Organometallics, Vol. 22, No. 4, 2003 793
Ta ble 5. Selected Bon d Len gth s [Å] a n d An gles
[d eg] for [P tMe(P MDETA)]CF 3SO3, 14
Sch em e 5. Meth yl(h yd r id o) Com p lexes w ith
P MDETA
Pt(1)-C(1)
Pt(1)-N(1)
2.027(7)
2.076(5)
Pt(1)-N(3)
Pt(1)-N(2)
2.072(5)
2.106(5)
C(1)-Pt(1)-N(3)
N(3)-Pt(1)-N(1)
N(3)-Pt(1)-N(2)
94.9(2)
166.5(2)
84.9(2)
C(1)-Pt(1)-N(1)
C(1)-Pt(1)-N(2)
N(1)-Pt(1)-N(2)
94.7(2)
179.1(2)
85.4(2)
both show clear evidence of deuterium incorporation.
In the case of methane, all isotopomers observable by
1H NMR, CH4, CH3D, CH2D2, and CHD3 were shown
to be present. This is indicative of H/D exchange similar
to that shown in Scheme 4. This is clearly a rapid
process, since it occurs during the brief time that the
hydride complex exists at room temperature. No further
H/D exchange into the methane or the methylplatinum
group of complex 14 occurred after one month of reaction
time, confirming that 14 is inactive as a catalyst for H/D
exchange. The reaction of 14 with triflic acid-d in CD3-
OD gave CH3D only.
and another was tentatively identified at δ 0.30 ppm,
but with platinum satellites obscured. By analogy with
the chemistry of Scheme 2, it is likely that the reluc-
tance of PMDETA to act as a fac-tridentate ligand leads
to partial formation of the hydride 12 with bidentate
PMDETA at -78 °C, with very easy conversion to 13
complete by -50 °C. Complex 13 was stable at -50 °C
but it had decomposed to give methane and the meth-
ylplatinum(II) complex 14 by -10 °C. The hydrides are
clearly much less stable than with PICO or BPICO
ligands. We suggest that this correlates with the
tendency of the ligands to form strong fac-tridentate
binding to platinum(IV).
Con clu sion s
This work shows how the stability of hydrido(di-
methyl)platinum(IV) complexes can be fine-tuned by
modification of a supporting, flexible tridentate ligand.
The ligands PICO and BPICO give hydridodimethyl-
platinum(IV) derivatives that decompose only slowly at
room temperature, while PMDETA gives a much less
stable hydride and is independently shown to be a
poorer fac-tridentate ligand for platinum(IV). In all
cases the thermal stability of the hydridodimethylplati-
num(IV) complexes with flexible tridentate ligands is
intermediate between derivatives with rigidly fac-tri-
dentate ligands (very stable) and those with bidentate
ligands (low thermal stability).6-9 The hydridodimeth-
ylplatinum(IV) complexes with PICO or BPICO ligands
can exist in three isomeric forms as shown in Scheme
3, and all three isomers have been identified by NMR
spectroscopy. Protonation of the dimethylplatinum(II)
precursor gives the product of kinetic control, in which
the hydride is trans to the NMe2 group, which can then
isomerize to the other two isomers. The product of
thermodynamic control has the hydride trans to the
pyridyl nitrogen donor. Hydrogen-deuterium exchange
reactions occur when the protonation reactions are
carried out in CD3OD solvent, and are interpreted in
terms of easy reversibility of the protonation of the
dimethylplatinum(II) complexes and easy equilibration
of the hydridodimethylplatinum(IV) complexes with
corresponding methyl(methane)platinum(II) complexes.
However, none of these platinum complexes activates
free methane at room temperature.
Complex 14 is formed rapidly by reaction of complex
3 with triflic acid at room temperature. It is character-
1
ized in the H NMR spectrum by the methylplatinum
resonance at δ 0.25 ppm [2J (PtH) ) 78 Hz]. The
structure of complex 14 was determined and is il-
lustrated in Figure 5, with selected bond distances and
angles given in Table 5. The complex has distorted
square-planar stereochemistry, the largest deviation
being the angle N(1)Pt(1)N(3) ) 166.5(2)°, which is
probably to minimize ring strain in the mer-tridentate
ligand. The mutually trans nitrogen atoms have almost
equal Pt-N distances and, as expected, both are shorter
than the Pt-N distance trans to the methylplatinum
group.
Reaction of complex 3 with CF3SO3D in methanol-d4
at room temperature gave complex 14 and methane, and
Exp er im en ta l Section
NMR spectra were recorded by using Varian Mercury 400
or Inova 400 spectrometers and chemical shifts are reported
relative to TMS. All reactions were carried out under a dry
nitrogen atmosphere by using standard Schlenk or drybox
techniques. The complex [Pt2Me4(µ-SMe2)2] was prepared
according to the literature method.11a
F igu r e 5. A view of the molecular structure of [PtMe-
(PMDETA)]+, showing 25% thermal ellipsoids. The hydro-
gen atoms are omitted for clarity.
(11) (a) Scott, J . D.; Puddephatt, R. J . Organometalllics 1983, 2,
1643. (b) Abdel-Magid, A. F.; Maryanoff, C. A.; Carson, K. G.
Tetrahedron Lett. 1990, 31, 5595.

794 Organometallics, Vol. 22, No. 4, 2003
Prokopchuk and Puddephatt
N,N,N′-Tr im eth yl-N′-(2-picolyl)eth ylen ediam in e, P ICO.
A mixture of 2-pyridinecarboxaldehyde (1.5 mL, 15.6 mmol),
N,N,N′-trimethylethylenediamine (2.3 mL, 17.2 mmol), and
sodium triacetoxyborohydride (4.8 g, 21.5 mmol) in dry THF
(60 mL) was stirred for 3 days. The reaction was quenched by
adding saturated NaHCO3 solution (120 mL) and the mixture
was extracted with CHCl3 (3 × 70 mL). The organic phase was
dried over anhydrous MgSO4 and filtered, and the solvent
evaporated to give the product as a colorless oil.11b Yield 1.8
g, 60%. NMR (CDCl3): δ(1H) 8.46 [dd, 1H, 3J (HH) ) 5 Hz,
[P tMe2(P MDETA)], 3. 3 was prepared similarly using
PMDETA. Anal. Calcd for C11H29N3Pt‚H2O: C, 31.72; H, 7.50;
N, 10.09. Found: C, 31.22, H, 7.26; N, 10.03. NMR (acetone-
d6): δ(1H) 3.49 [td, 2H, 3J (HH) ) 13 Hz, 2J (HH) ) 3 Hz, CH2];
3
3.36 [m, 2H, CH2]; 2.85 [m, 4H, CH2]; 2.60 [s, 3H, J (PtH) )
21 Hz, Pt-NMe]; 2.55 [s, 6H, 3J (PtH) ) 21 Hz, Pt-NMe2];
2.15 [s, 6H, NMe2]; 0.17 [s, 3H, 2J (PtH) ) 89 Hz, Pt-Me]; 0.12
ppm [s, 3H, 2J (PtH) ) 87 Hz, Pt-Me]. δ(13C) 61.95 [s, 2J (PtC)
2
) 7 Hz, CH2]; 57.82 [s, J (PtC) ) 6 Hz, CH2]; 57.23 [s, CH2];
2
57.05 [s, CH2]; 49.58 [s, J (PtC) ) 10 Hz, Pt-NMe2]; 47.79 [s,
1
4J (HH) ) 2 Hz, py]; 7.57 [td, 1H, J (HH) ) 8 Hz, J (HH) ) 2
Hz, py]; 7.35 [d, 1H, 3J (HH) ) 8 Hz, py]; 7.05 [dd, 1H, 3J (HH)
) 8 Hz, 5 Hz, py]; 3.60 [s, 2H, CH2]; 2.48 [m, 2H, CH2]; 2.38
[m, 2H, CH2]; 2.21 [s, 3H, NMe]; 2.14 ppm [s, 6H, NMe2]. δ(13C)
159.50 [s, py]; 149.23 [s, py]; 136.55 [s, py]; 123.33 [s, py];
122.12 [s, py]; 64.60 [s, CH2]; 57.53 [s, CH2]; 55.67 [s, CH2];
46.00 [s, NMe2]; 43.00 ppm [s, NMe].
3
4
NMe2]; 46.74 [s, NMe]; -22.00 [s, J (PtC) ) 859 Hz, Pt-Me];
1
-23.30 ppm [s, J (PtC) ) 855 Hz, Pt-Me].
[P tMe3(P ICO)]I, 4. To a solution of [PtMe2(PICO)] (0.55
mmol) in THF (5 mL), prepared in situ, was added MeI (34
µL, 0.55 mmol). The product formed as a pale yellow precipi-
tate. The mixture was stirred for 30 min, pentane (30 mL) was
added to complete precipitation of the product, the solvent was
removed by cannula, and the solid product was dried under
vacuum. Yield 153 mg, 52%. Anal. Calcd for C14H28N3IPt: C,
30.01; H, 5.04; N, 7.50. Found: C, 30.44; H, 5.05; N, 7.27. NMR
N -B e n zy l-N ′,N ′-d im e t h y l-N -(2-p ic o ly l)e t h y le n e d i-
a m in e, BP ICO. BPICO was prepared similarly from N-
benzyl-N′,N′-dimethylethylenediamine. Yield 88%. NMR
(CDCl3): δ(1H) 8.48 [d, 1H, 3J (HH) ) 6 Hz, 4J (HH) ) 2 Hz,
3
3
(acetone-d6): δ(1H) 8.75 [d, 1H, J (HH) ) 6 Hz, J (PtH) ) 11
Hz, py]; 8.24 [td, 1H, 3J (HH) ) 8 Hz, 4J (HH) ) 2 Hz, py]; 7.98
[d, 1H, 3J (HH) ) 8 Hz, py]; 7.76 [td, 1H, 3J (HH) ) 6 Hz, 4J (HH)
) 1 Hz, py]; 4.98 [d, 1H, 3J (PtH) ) 19 Hz, 2J (HH) ) 16 Hz,
3
4
py]; 7.62 [td, 1H, J (HH) ) 8 Hz, J (HH) ) 2 Hz, py]; 7.52 [d,
1H, 3J (HH) ) 8 Hz, py]; 7.35 [d, 2H, 3J (HH) ) 7 Hz, Ph]; 7.28
3
3
[t, 2H, J (HH) ) 7 Hz, Ph]; 7.27 [t, 1H, J (HH) ) 7 Hz, Ph];
7.10 [t, 1H, 3J (HH) ) 6 Hz, py]; 3.77 [s, 2H, NCH2Ph]; 3.65 [s,
2H, NCH2py]; 2.62 [m, 2H, NCH2CH2N]; 2.45 [m, 2H, NCH2-
CH2N]; 2.15 ppm [s, 6H, NMe2]. δ(13C) 160.28 [s, py]; 148.97
[s, py]; 139.42 [s, Ph]; 136.55 [s, py]; 128.98 [s, Ph]; 128.40 [s,
ph]; 127.12 [s, Ph]; 122.99 [s, py]; 122.05 [s, py]; 60.88 [s, CH2];
59.42 [s, CH2]; 57.88 [s, CH2]; 52.26 [s, CH2]; 46.21 ppm [s,
NMe2].
2
NCH2py]; 4.47 [d, 1H, J (HH) ) 16 Hz, NCH2py]; 3.21-3.09
[m, 4H, NCH2CH2N]; 2.90 [s, 3H, 3J (PtH) ) 17 Hz, Pt-NMe];
3
3
2.55 [s, 3H, J (PtH) ) 17 Hz, Pt-NMe2]; 2.24 [s, 3H, J (PtH)
) 10 Hz, Pt-NMe2]; 0.95 [s, 3H, 2J (PtH) ) 68 Hz, Pt-Me trans
NMe]; 0.79 [s, 3H, 2J (PtH) ) 69 Hz, Pt-Me trans py]; 0.54
ppm [s, 3H, 2J (PtH) ) 69 Hz, Pt-Me trans NMe2]. δ(13C)
3
159.02 [s, py]; 146.85 [s, J (PtC) ) 11 Hz, py]; 140.48 [s, py];
126.15 [s, 2J (PtC) ) 12 Hz, py]; 125.19 [s, 3J (PtC) ) 9 Hz, py];
[P tMe2(P ICO)], 1. A mixture of [PtMe2(µSMe2)]2 (150 mg,
0.261 mmol) and pico (103 mg, 0.532 mmol) in THF (5 mL)
was stirred for 2 h to give an orange solution of the product,
which was usually used in situ for further reactions. Complex
1 could be isolated by evaporation of the solvent and was
crystallized with difficulty from CH2Cl2/thf/pentane. Anal.
Calcd for C13H25N3Pt‚thf: C, 41.61; H, 6.78; N, 8.57. Found:
C, 41.17; H, 6.34; N, 8.29. NMR (acetone-d6): δ(1H) 8.72 [d,
1H, 3J (PtH) ) 22 Hz, 3J (HH) ) 7 Hz, py]; 8.02 [td, 1H, 3J (HH)
66.91 [s, CH2]; 61.19 [s, CH2]; 59.88 [s, CH2]; 47.50 [s, NMe2];
1
47.33 [s, NMe2]; 45.14 [s, NMe]; -3.90 [s, J (PtC) ) 712 Hz,
1
Pt-Me]; -4.53 [s, J (PtC) ) 677 Hz, Pt-Me]; -7.62 ppm [s,
1J (PtC) ) 674 Hz, Pt-Me].
[P tMe3(BP ICO)]I, 5. 5 was prepared similarly from [PtMe2-
(BPICO)]. Yield 72%. Anal. Calcd for C20H32N3IPt: C, 37.74;
H, 5.07; N, 6.60. Found: C, 37.42; H, 5.22; N, 6.23. NMR
3
4
(acetone-d6): δ(1H) 8.77 [d, 1H, J (PtH) ) 12 Hz, J (HH) ) 6
Hz, py]; 8.19 [td, 1H, 3J (HH) ) 8 Hz, 4J (HH) ) 2 Hz, py]; 7.88
4
3
) 8 Hz, J (HH) ) 2 Hz, py]; 7.52 [d, 1H, J (HH) ) 8 Hz, py];
3
3
[d, 1H, J (HH) ) 8 Hz, py]; 7.74 [t, 1H, J (HH) ) 6 Hz, py];
7.32 [td, 1H, 3J (HH) ) 7 Hz, 4J (HH) ) 0.4 Hz, py]; 4.24 [d,
1H, J (HH) ) 15 Hz, NCH2py]; 3.90 [d, 1H, J (HH) ) 15 Hz,
2
7.68 [m, 2H, Ph]; 7.47 [m, 3H, Ph]; 4.82 [d, 1H, J (HH) ) 16
2
2
2
3
Hz, CH2]; 4.52 [d, 1H, J (HH) ) 14 Hz, J (PtH) ) 5 Hz, CH2];
NCH2py]; 2.97 [m, 1H, NCH2CH2N]; 2.81 [m, 1H, NCH2CH2N];
2
3
4.31 [d, 1H, J (HH) ) 16 Hz, J (PtH) ) 20 Hz, CH2]; 4.18 [d,
3
2.69 [s, 3H, J (PtH) ) 14 Hz, Pt-NMe]; 2.68 [m, 2H, NCH2-
1H, 2J (HH) ) 14 Hz, 3J (PtH) ) 5 Hz, CH2]; 3.45-3.33 [m, 4H,
2
CH2N]; 2.08 [s, 6H, NMe2]; 0.54 [s, 3H, J (PtH) ) 90 Hz, Pt-
3
NCH2CH2N]; 2.63 [s, 3H, J (PtH) ) 16 Hz, Pt-NMe]; 2.27 [s,
Me]; 0.49 ppm [s, 3H, 2J (PtH) ) 86 Hz, Pt-Me]. δ(13C) 160.38
3H, 3J (PtH) ) 10 Hz, Pt-NMe]; 1.02 [s, 3H, 2J (PtH) ) 68 Hz,
2
[s, py]; 145.81 [s, J (PtC) ) 33 Hz, py]; 135.86 [s, py]; 124.36
2
Pt-Me trans N]; 0.90 [s, 3H, J (PtH) ) 68 Hz, Pt-Me trans
py]; 0.66 ppm [s, 3H, J (PtH) ) 69 Hz, Pt-Me trans NMe2].
2
[s, J (PtC) ) 20 Hz, py]; 123.09 [s, py]; 67.69 [s, CH2]; 57.81
2
[s, CH2]; 56.86 [s, 2J (PtC) ) 26 Hz, CH2]; 48.11 [s, NMe]; 45.39
δ(13C) 146.56 [s, 3J (PtC) ) 12 Hz, py]; 140.44 [s, py]; 132.72
[s, Ph]; 131.44 [s, Ph]; 129.26 [s, Ph]; 128.84 [s, Ph]; 126.07 [s,
2J (PtC) ) 13 Hz, py]; 125.29 [s, br, py]; 63.60 [s, CH2]; 60.98
[s, CH2]; 58.72 [br, CH2]; 47.51 [s, NMe2]; 47.21 [s, NMe2];
-3.42 [s, Pt-Me]; -3.96 [s, Pt-Me]; -7.15 ppm [s, Pt-Me].
[P tMe3(P MDETA)]I, 6a , a n d [P tMe3I(P MDETA)], 7. 6a
and 7 were prepared similarly, as a mixture of isomers, from
[PtMe2(PMDETA)]. Yield 52%. Anal. Calcd for C12H32N3IPt:
C, 26.67; H, 5.97; N, 7.78. Found: C, 26.80; H, 5.97; N, 7.33.
NMR (acetone-d6): 6a : δ(1H) 2.81 [s, 6H, 3J (PtH) ) 8 Hz, Pt-
NMe2]; 2.71 [s, 3H, 3J (PtH) ) 18 Hz, Pt-NMe]; 2.51 [s, 6H,
3J (PtH) ) 16 Hz, Pt-NMe2]; 0.88 [s, 6H, 2J (PtH) ) 69 Hz,
1
[s, NMe2]; -19.24 [s, J (PtC) ) 838 Hz, Pt-Me]; -21.35 ppm
1
[s, J (PtC) ) 843 Hz, Pt-Me].
[P t Me2(BP ICO)], 2.
2 was prepared similarly using
BPICO. Anal. Calcd for C19H29N3Pt: C, 46.14; H, 5.91; N, 8.50.
Found: C, 45.81; H, 6.12; N, 8.23. NMR (acetone-d6): δ(1H)
8.72 [d, 1H, 3J (PtH) ) 26 Hz, 3J (HH) ) 5 Hz, py]; 7.97 [td,
1H, 3J (HH) ) 8 Hz, 4J (HH) ) 1 Hz, py]; 7.70 [m, 2H, Ph];
7.45 [d, 1H, 3J (HH) ) 8 Hz, py]; 7.30-7.25 [m, 4H, py/Ph];
2
2
4.60 [d, 1H, J (HH) ) 11 Hz, CH2Ph]; 4.12 [d, 1H, J (HH) )
2
11 Hz, CH2Ph]; 4.11 [d, 1H, J (HH) ) 15 Hz, CH2py]; 3.99 [d,
1H, J (HH) ) 15 Hz, CH2py]; 3.25 [m, 1H, NCH2CH2N]; 2.98
2
2
[m, 1H, NCH2CH2N]; 2.84 [m, 1H, NCH2CH2N]; 2.59 [m, 1H,
NCH2CH2N]; 2.09 [s, 6H, NMe2]; 0.62 [s, 3H, 2J (PtH) ) 90
Hz, Pt-Me]; 0.49 ppm [s, 3H, 2J (PtH) ) 85 Hz, Pt-Me]. δ(13C)
Pt-Me trans NMe2]; 0.73 ppm [s, 3H, J (PtH) ) 66 Hz, Pt-
Me trans NMe]. 7: δ(1H) 3.22 [s, 3H, 3J (PtH) ) 11 Hz, Pt-
NMe]; 2.48 [s, 3H, 3J (PtH) ) 16 Hz, Pt-NMe]; 2.42 [s, 3H,
3J (PtH) ) 15 Hz, Pt-NMe]; 2.41 [s, 3J (PtH) ) 16 Hz, Pt-
2
160.77 [s, py]; 145.71 [s, J (PtC) ) 34 Hz, py]; 135.79 [s, py];
2
133.67 [s, Ph]; 132.31 [s, Ph]; 128.27 [s, Ph]; 127.98 [s, Ph];
NMe]; 2.16 [s, 6H, uncoord NMe2]; 1.26 [s, 3H, J (PtH) ) 70
2
2
124.17 [s, J (PtC) ) 20 Hz, py]; 123.18 [s, py]; 63.84 [s, CH2];
Hz, Pt-Me]; 1.25 [s, 3H, J (PtH) ) 72 Hz, Pt-Me]; 1.21 ppm
62.91 [s, CH2]; 57.16 [s, 2J (PtC) ) 28 Hz, CH2]; 54.59 [s, CH2];
[s, 3H, 2J (PtH) ) 71 Hz, Pt-Me]. The CH2 resonances were
observed in the range δ(1H) ) 2.90-4.00, as complex, overlap-
ping multiplets, and were not assigned to specific protons.
45.54 [s, NMe2]; -18.34 [s, 1J (PtC) ) 843 Hz, Pt-Me]; -21.08
1
ppm [s, J (PtC) ) 853 Hz, Pt-Me].

Methyl(hydrido)platinum(IV) Complexes
Organometallics, Vol. 22, No. 4, 2003 795
[P tMe3(P MDETA)]CF 3SO3. This was prepared similarly
from CF3SO3Me and [PtMe2(PMDETA)]. NMR(acetone-d6):
δ(1H) 3.25 [m, 2H, CH2]; 3.08 [m, 2H, CH2]; 3.05 [m, 2H, CH2];
2.96 [m, 2H, CH2]; 2.78 [s, 6H, 3J (PtH) ) 8 Hz, Pt-NMe2];
overlapped and were not assigned to a specific isomer. δ 8.17-
7.64 [m, py]; 7.64-7.46 [m, Ph]; 3.76-3.35 ppm [m, NCH2-
CH2N].
H/D Exch a n ge w ith [P tMe2(P ICO)]. To a solution of
[PtMe2(PICO)] (0.11 mmol) in methanol-d4 (0.5 mL) was added
CF3SO3D [18.5 µL, 0.209 mmol] in an NMR tube. The reaction
3
3
2.68 [s, 3H, J (PtH) ) 18 Hz, Pt-NMe]; 2.49 [s, 6H, J (PtH)
) 16 Hz, Pt-NMe2]; 0.87 [s, 6H, 2J (PtH) ) 69 Hz, Pt-Me trans
NMe2]; 0.72 ppm [s, 3H, 2J (PtH) ) 66 Hz, Pt-Me trans NMe].
[P tMe2H(P ICO)]BF 4, 8c. To a solution of complex 1 (0.53
mmol) in THF (5 mL) was added HBF4 (54% solution in Et2O,
133 µL, 0.53 mmol). A pale yellow precipitate of the product
was formed. After 2 min, pentane (30 mL) was added to ensure
complete precipitation. The solvent was removed by cannula,
and the product was dried under vacuum. Yield 180 mg, 68%.
Anal. Calcd for C13H26N3PtBF4: C, 30.84; H, 5.18; N, 8.30.
Found: C, 30.37; H, 4.73; N, 7.89. The complex was identified
as 8c with traces of isomers 8a and 8b present. NMR (acetone-
1
was monitored by HNMR spectroscopy. As reductive elimina-
tion of methane progressed, over 1 day at room temperature,
the peaks for [Pt(CH3-nDn)(PICO)]+ (n ) 1, 2) appeared: δ(1H)
2
0.52 [s, 3H, 2J (PtH) ) 78 Hz, Pt-Me]; 0.50 [t, J (HD) ) 2 Hz,
Pt-CH2D]; 0.48 ppm [m, Pt-CHD2]; as well as peaks for the
isotopomers of methane, δ(1H) 0.19 [s, CH4]; 0.17 [t, 2J (HD) )
2 Hz, CH3D]; 0.15 [quint,2J (HD) ) 2 Hz, CH2D2]; 0.13 ppm
[sept, CHD3].
H/D Exch a n ge w ith [P tMe2(BP ICO)]. This was carried
out similarly but using [PtMe2(BPICO)]. 1H NMR (CD3OD):
[PtCH3-nDn(BPICO)]+ (n ) 0, 1, 2): δ(1H) 0.58 [s, 3H, 2J (PtH)
) 79 Hz, Pt-Me]; 0.56 [t, 2J (HD) ) 2 Hz, Pt-CH2D]; 0.54 ppm
3
3
d6): 8c: δ(1H) 8.59 [d, 1H, J (PtH) ) 17 Hz, J (HH) ) 6 Hz,
3
4
py]; 8.17 [td, 1H, J (HH) ) 8 Hz, J (HH) ) 2 Hz, py]; 7.80 [d,
1H, J (HH) ) 8 Hz, py]; 7.71 [t, 1H, J (HH) ) 6 Hz, py]; 4.62
3
3
[m, Pt-CHD2]; and CHnD4-n
:
δ(1H) 0.19 [s, CH4]; 0.17 [t,
3
3
2
2J (HD) ) 2 Hz, CH3D]; 0.15 [quint, J (HD) ) 2 Hz, CH2D2];
[d, 1H, J (HH) ) 16 Hz, NCH2py]; 4.50 [d, 1H, J (HH) ) 16
Hz, NCH2py]; 3.31-3.00 [m, 4H, NCH2CH2N]; 3.24 [s, 3H,
3J (PtH) ) 22 Hz, Pt-NMe]; 2.95 [s, 3H, 3J (PtH) ) 25 Hz, Pt-
0.13 ppm [m, CHD3].
[P t Me(P ICO)][CF 3SO3]. To a solution of [PtMe2(PICO)]
(0.52 mmol) in THF (5 mL) was added triflic acid (46.5 µL,
0.53 mmol) to give a pale orange solution. The solution was
stirred at 60 °C for 3 h, then for 12 h at 53 °C, followed by
addition of pentane (20 mL) to precipitate the product, which
was separated and dried under vacuum. Yield 225 mg, 78%.
Anal. Calcd for C13H22N3F3O3SPt: C, 28.26; H, 4.01; N, 7.61.
Found: C, 28.20; H, 4.11; N, 7.26. NMR (acetone-d6): δ(1H)
8.54 [d, 1H, 3J (HH) ) 6 Hz, 3J (PtH) ) 49 Hz, py]; 8.18 [td,
3
NMe2]; 2.27 [s, 3H, J (PtH) ) 10 Hz, Pt-NMe2]; 0.97 [s, 3H,
2J (PtH) ) 67 Hz, Pt-Me trans NMe]; 0.60 [s, 3H, J (PtH) )
2
68 Hz, Pt-Me trans NMe2]; -20.95 ppm [s, 1H, 1J (PtH) ) 1425
Hz, Pt-H]. IR(Nujol): νPt-H ) 2261 cm-1
.
Com p lexes 8a -c. The selectivity of isomer formation was
studied by NMR in a typical experiment as follows. To a
solution of complex 1 (0.105 mmol) in acetone-d6 (0.5 mL) was
added CF3SO3H (0.105 mmol), and the isomeric mixture of
3
4
3
1
1H, J (HH) ) 8 Hz, J (HH) ) 2 Hz, py]; 7.69 [d, 1H, J (HH)
) 8 Hz, py]; 7.52 [t, 1H, 3J (HH) ) 6 Hz, py]; 4.62 [d, 1H,
2J (HH) ) 15 Hz, NCH2py]; 4.40 [d, 1H, 2J (HH) ) 15 Hz, NCH2-
py]; 3.79 [td, 2H, 2J (HH) ) 3 Hz, 3J (HH) ) 14 Hz, NCH2CH2N];
3.72 [td, 2H, 2J (HH) ) 2 Hz, 3J (HH) ) 14 Hz, NCH2CH2N];
8a -c was analyzed by H NMR spectroscopy. NMR (acetone-
3
3
d6): 8a : δ(1H) 8.75 [d, 1H, J (PtH) ) 17 Hz, J (HH) ) 6 Hz,
4
3
py]; 8.21 [td, 1H, J (HH) ) 2 Hz, J (HH) ) 8 Hz, py]; 7.91 [d,
1H, 3J (HH) ) 8 Hz, py]; 7.73 [td, 1H, 3J (HH) ) 6 Hz, py]; 4.91
[d, 1H, 3J (HH) ) 16 Hz, 3J (PtH) ) 25 Hz,NCH2py]; 4.64 [d,
1H, 3J (HH) ) 16 Hz, NCH2py]; 3.30-3.00 [m, 4H, NCH2CH2];
3
3
3.03 [s, 3H, J (PtH) ) 12 Hz, Pt-NMe]; 2.88 [s, 3H, J (PtH)
3
3
3
) 44 Hz, Pt-NMe]; 2.74 [s, 3H, J (PtH) ) 16 Hz, Pt-NMe];
3.05 [s, 3H, J (PtH) ) 19 Hz, Pt-NMe]; 2.48 [s, 3H, J (PtH)
) 17 Hz, Pt-NMe2 trans H]; 2.17 [s, 3H, 3J (PtH) ) 9 Hz, Pt-
NMe2 trans H]; 0.97 [s, 3H, 2J (PtH) ) 66 Hz, Pt-Me trans
NMe]; 0.86 [s, 3H, 2J (PtH) ) 69 Hz, Pt-Me trans py]; -21.18
0.52 ppm [s, 3H, J (PtH) ) 78 Hz, Pt-Me]. δ(13C) 165.82 [s,
2
2
py]; 149.31 [s, J (PtC) ) 38 Hz, py]; 139.40 [s, py]; 125.65 [s,
2J (PtC) ) 44 Hz, py]; 124.99 [s, 3J (PtC) ) 27 Hz, py]; 70.71 [s,
2J (PtC) ) 22 Hz, CH2]; 65.51 [s, J (PtC) ) 29 Hz, CH2]; 57.98
2
1
ppm [s, 1H, J (PtH) ) 1438 Hz, Pt-H trans NMe2]. 8b: This
[s, 2J (PtC) ) 16 Hz, CH2]; 52.58 [s, Pt-NMe]; 50.88 [s, Pt-
NMe]; 43.21 [s, 2J (PtC) ) 48 Hz, Pt-NMe]; -13.10 ppm [s,
1J (PtC) ) 811 Hz, Pt-Me].
was always a minor isomer and many resonances were
obscured. δ(1H) 0.86 [s, 3H, 2J (PtH) ) 69 Hz, Pt-Me trans
py]; 0.62 [s, 3H, 2J (PtH) ) 67 Hz, Pt-Me trans NMe2]; -20.65
1
[s, 1H, J (PtH) ) 1406 Hz, Pt-H trans NMe]. 8c: See above.
[P tMe(BP ICO)][CF 3SO3]. To a solution of [PtMe2(BPICO)]
(0.52 mmol) in THF (5 mL) was added triflic acid (46 µL, 0.52
mmol). The solution was stirred overnight at 45 °C, then cooled
to room temperature, and ether (30 mL) was added to
precipitate the product, which was separated and dried under
vacuum. Yield 246 mg, 75%. Anal. Calcd for C19H26N3F3O3-
SPt: C, 36.31; H, 4.17; N, 6.69. Found: C, 36.45; H, 4.15; N,
6.44. NMR (acetone-d6): δ(1H) 8.39 [d, 1H, 3J (HH) ) 6 Hz,
[P tMe2H(BP ICO)]CF 3SO3, 9a -c. To a solution of complex
2 in THF (5 mL) was added triflic acid (48.5 µL, 0.55 mmol).
After 1 min, ether (25 mL) was added to precipitate the
product. The solvent was removed by cannula, and the residue
was dried under vacuum to give an off-white solid, identified
as a mixture of isomers 9a -c. Yield 246 mg, 73%. Anal. Calcd
for C20H30N3PtF3SO3: C, 37.27; H, 4.69; N, 6.52. Found: C,
36.83; H, 4.37; N, 6.17. NMR (acetone-d6): 9a : δ(1H) 8.78 [d,
1H, 3J (PtH) ) 12 Hz, 3J (HH) ) 6 Hz, py]; 4.94 [d, 1H, 2J (HH)
4
3
3J (PtH) ) 50 Hz, py]; 7.99 [td, 1H, J (HH) ) 1 Hz, J (HH) )
3
8 Hz, py]; 7.59 [m, 2H, Ph]; 7.48 [d, 1H, J (HH) ) 8 Hz, py];
3
2
3
7.33 [t, 1H, J (HH) ) 6 Hz, py]; 7.21 [m, 3H, Ph]; 4.61 [s, 2H,
) 16 Hz, CH2]; 4.60 [d, 1H, J (HH) ) 14 Hz, J (PtH) ) 5 Hz,
2
2
2
NCH2py]; 4.29 [d, 2H, J (HH) ) 4 Hz, NCH2Ph]; 3.81 [d, 2H,
CH2]; 4.48 [d, 1H, J (HH) ) 16 Hz, CH2]; 4.43 [d, 1H, J (HH)
3J (HH) ) 10 Hz, NCH2CH2N]; 3.32 [t, 2H, 3J (HH) ) 10 Hz,
3
) 14 Hz, CH2]; 2.55 [s, 3H, J (PtH) ) 16 Hz, Pt-NMe2]; 2.19
NCH2CH2N]; 3.06 [s, 3H, 3J (PtH) ) 48 Hz, Pt-NMe2]; 2.92
3
2
[s, 3H, J (PtH) ) 9 Hz, Pt-NMe2]; 1.05 [s, 3H, J (PtH) ) 66
Hz, Pt-Me trans N]; 1.01 [s, 3H, 2J (PtH) ) 68 Hz, Pt-Me
trans py]; -20.99 ppm [s, 1H, 1J (PtH) ) 1435 Hz, Pt-H trans
NMe2]. 9b: This was always a minor isomer and most
resonances were obscured. δ(1H) -21.05 ppm [s, 1J (PtH) )
3
2
[s, 3H, J (PtH) ) 43 Hz, Pt-NMe2]; 0.58 ppm [s, 3H, J (PtH)
) 79 Hz, Pt-Me].
[P t Me2H (P MDE TA)][CF 3SO3], 13, a n d [P t Me2H -
(P MDETA)(a ceton e)][CF 3SO3], 12. To a solution of [PtMe2-
(PMDETA)] (0.11 mmol) in acetone-d6 (0.5 mL) in an NMR
tube at -78 °C was added triflic acid (10 µL, 0.11 mmol). The
reaction was monitored as a function of temperature. NMR
1440 Hz, Pt-H trans NBz]. 9c: δ(1H) 8.63 [d, 1H, J (PtH) )
3
13 Hz, 3J (HH) ) 6 Hz, py]; 4.86 [d, 1H, 2J (HH) ) 16 Hz, CH2];
2
3
4.76 [d, 1H, J (HH) ) 14 Hz, J (PtH) ) 9 Hz, CH2]; 4.54 [d,
1H, 2J (HH) ) 14 Hz, 3J (PtH) ) 12 Hz, CH2]; 4.40 [d, 1H,
(acetone-d6, 193 K): 13: δ(1H) 0.80 [s, 3H, J (PtH) ) 68 Hz,
2
2J (HH) ) 16 Hz, J (PtH) ) 19 Hz, CH2]; 2.94 [s, 3H, J (PtH)
) 25 Hz, Pt-NMe2]; 2.27 [s, 3H, 3J (PtH) ) 10 Hz, Pt-NMe2];
1.04 [s, 3H, 2J (PtH) ) 67 Hz, Pt-Me trans N]; 0.65 [s, 3H,
2J (PtH) ) 67 Hz, Pt-Me trans NMe2]; -20.65 ppm [s, 1H,
1J (PtH) ) 1412 Hz, Pt-H trans py]. The following resonances
Pt-Me]; 0.77 [s, 3H, 2J (PtH) ) 64 Hz, Pt-Me]; -22.60 ppm [s,
3
3
1H, 1J (PtH) ) 1484 Hz, Pt-H]. 12: δ(1H) 0.76 [s, 3H, 2J (PtH)
2
) 66 Hz, Pt-Me]; 0.30 [s, 3H, J (PtH) not resolved, Pt-Me];
-22.24 ppm [s, 1J (PtH) ) 1474 Hz, Pt-H]. Ligand resonances
were not assigned, but were observed in the ranges 3.6-3.0

796 Organometallics, Vol. 22, No. 4, 2003
Prokopchuk and Puddephatt
Ta ble 6. Cr ysta l Da ta a n d Str u ctu r e Refin em en t for Com p lexes 5[I], 9[CF 3SO3], 11[CF 3SO3], a n d 14[CF 3SO3]
5[I]
9[CF3SO3]
11[CF3SO3]
14[CF3SO3]
formula
fw
C
20H32IN3Pt
C13H22F3N3O3PtS
552.49
C19H26F3N3O3PtS
628.58
C11H26F3N3O3PtS
532.50
636.48
T/K
200(2)
200(2)
200(2)
200(2)
λ/Å
cryst sys
space group.
a/Å
b/Å
c/Å
R/deg
â/deg
0.71073
orthorhombic
P212121
12.533(3)
17.008(3)
10.243(2)
90
0.71073
monoclinic
P21/c
22.3918(6)
8.8440(2)
20.0096(5)
90
116.477(2)
90
0.71073
triclinic
P-1
0.71073
monoclinic
C2/c
25.8182(11)
8.3118(3)
19.7761(8)
90
122.889(1)
90
3563.7(2), 8
1.985
13.0580(2)
13.2793(2)
15.5937(3)
105.8830(7)
98.5800(8)
116.5400(8)
2207.84(6), 4
1.891
90
90
γ/deg
V/Å3, Z
2183.4(7), 4
1.936
7.848
3546.9(1), 8
2.069
8.076
dc/Mg/m3
abs coeff/mm-1
F(000)
6.500
1224
8.033
2064
1216
2128
no. of reflns, ind reflns
abs corr
6371, 6371
integration
6371/0/231
51105, 15589
integration
15589/3/434
15223, 10090
integration
10090/12/547
19129, 5220
integration
5220/0/200
no. of data/restraints/
parameters
goodness-of-fit on F2
R[I > 2σ(I)]: R1, wR2
R(all data): R1, wR2
1.001
0.0393, 0.0616
0.0666, 0.0679
1.073
0.0547, 0.1369
0.0775, 0.1454
1.010
0.0455, 0.1101
0.0718, 0.1217
1.019
0.0410, 0.0995
0.0548, 0.1035
[CH2]; 3.0-2.3 [NMe]. At 223K, resonances of 12 were very
weak and 13 was the major complex present. At 263K,
reductive elimination to give methane and complex 14 (NMR
data given below) was complete.
H/D Exch a n ge w ith [P tMe2(P MDETA)]. This reaction
was carried out similarly but using excess triflic acid-d (18.5
µL, 0.21 mmol) with [PtMe2(PMDETA)] (0.11 mmol) in meth-
anol-d4 (0.5 mL) at room temperature. After 40 min, the
Str u ctu r e Deter m in a tion s. Crystals of complexes 5, 9,
11, and 14 were grown by slow diffusion of pentane into
concentrated acetone solutions and then mounted on glass
fibers. Data were collected at -73 °C using a Nonius Kappa-
CCD diffractometer with COLLECT (Nonius B.V., 1998)
software. The unit cell parameters were calculated and refined
from the full data set. Crystal cell refinement and data
reduction were carried out using DENZO (Nonius B.V., 1998).
The data were scaled using SCALEPACK (Nonius B.V., 1998).
The crystal data and refinement parameters are listed in Table
6. The SHELXTL V5.1 (Sheldrick, G. M.) suite of programs
were used to solve the structures, followed by refinement using
successive difference Fouriers.
One of the triflate anions of 11 shows relatively large
thermal parameters on the O and F atoms, and an ISOR
restraint was placed on O6 and F6. All of the non-hydrogen
atoms in all three structures were refined with anisotropic
thermal parameters. The hydrogen atom positions were cal-
culated geometrically and were included as riding on their
respective carbon atoms.
1H NMR spectrum indicated formation of [PtCHnD3-n
-
2
(PMDETA)]CF3SO3: δ(1H) 0.24 [s, 3H, J (PtH) ) 78 Hz, Pt-
Me]; 0.23 [br, Pt-CH2D]; 0.21 ppm [br, Pt-CHD2]; and
2
methane: δ(1H) 0.15 [s, CH4]; 0.14 [t, J (HD) ) 2 Hz, CH3D];
0.13 [quint, CH2D2]; 0.11 ppm [m, CHD3]. Within 4 h, fur-
ther reaction occurred to give CHnD4-n and [Pt(O3SCF3)-
(PMDETA)]CF3SO3.
[P t Me(P MDE TA)][CF 3SO3]. To a solution of [PtMe2-
(PMDETA)] (0.41 mmol) in THF (5 mL) was added triflic acid
(37 µL, 0.42 mmol). The solution was stirred for 20 min, then
pentane (20 mL) was added to give the product as a white
precipitate, which was separated and dried under vacuum.
Yield 150 mg, 70%. Anal. Calcd for C11H26N3F3O3SPt: C, 24.81;
H, 4.92; N, 7.89. Found: C, 25.29; H, 4.90; N, 7.70. NMR
Ack n ow led gm en t. We thank Michael J ennings for
assistance with the X-ray crystallography and NSERC
(Canada) for financial support. R.J .P. thanks the Gov-
ernment of Canada for a Canada Research Chair.
Su p p or tin g In for m a tion Ava ila ble: X-ray crystallo-
graphic data for the structure determinations. This material
is available free of charge via the Internet at http://pubs.acs.org.
2
3
(acetone-d6): δ(1H) 3.62 [td, 4H, J (HH) ) 3 Hz, J (HH) ) 14
Hz, CH2]; 3.55 [td, 4H, 2J (HH) ) 2 Hz, 3J (HH) ) 14 Hz, CH2];
3
3
2.94 [s, 6H, J (PtH) ) 50 Hz, Pt-NMe2]; 2.77 [s, 3H, J (PtH)
) 46 Hz, Pt-NMe]; 0.25 ppm [s, 3H, 2J (PtH) ) 78 Hz, Pt-
Me]. δ(13C) 69.97 [s, J (PtC) ) 21 Hz, CH2]; 58.16 [s, J (PtC)
2
2
) 17 Hz, CH2]; 52.85 [s, Pt-NMe2]; 51.89 [s, Pt-NMe2]; 41.90
[s, Pt-NMe]; -13.30 ppm [s, J (PtC) ) 845 Hz, Pt-Me].
1
OM0206352