Terminal Platinum(II) Perfluoroacyl Phosphido Complexes: Synthesis and Dynamic Processes

Article abstract of DOI:10.1021/om9903691

The Pt(II) phosphido methyl complexes Pt(dppe)(Me)(PPhR) (dppe = Ph₂PCH₂CH₂PPh₂, R = i-Bu, 1; R = Is = 2,4,6-(i-Pr)₃C₆H₂, 2) have been prepared by proton transfer from secondary phosphines to the methoxide ligand of Pt(dppe)(Me)(OMe). Oxidative addition of ClC(O)C₃F₇ to Pt(PPh₂Me)₄ gives trans-Pt(PPh₂Me)₂(COC₃F₇)(Cl) (3); treatment of 3 with dppe yields Pt(dppe)(COC₃F₇)(Cl) (4). Complexes 3·0.5CH₂Cl₂ and 4 were structurally characterized by X-ray crystallography. Reaction of 4 with AgBF₄ and a secondary phosphine or treatment of [Pt(dppe)(COC₃F₇)(NCMe)][BF₄] (5) with a secondary phosphine gives the cations [Pt(dppe)(COC₃F₇)(PHPhAr)][BF₄] (Ar = Mes = 2,4,6-Me₃C₆H₂, 6; Ar = o-anisyl, 7; Ar = Is, 8; Ar = Mes-F₉ = 2,4,6-(CF₃)₃C₆H₂, 9; Ar = Ph, 10). Deprotonation of the cations with LiN(SiMe₃)₂ affords the phosphido complexes Pt(dppe)(COC₃F₇)(PPhAr) (Ar = Mes, 11; Ar = o-anisyl, 12; Ar = Is, 13; Ar = Mes-F₉, 14; Ar = Ph, 15). Fluxional processes in complexes 11-15 were studied by variable-temperature multinuclear NMR spectroscopy; the spectra are consistent with rapid phosphorus inversion on the NMR time scale at room temperature.

Full text of DOI:10.1021/om9903691

5130
Organometallics 1999, 18, 5130-5140
Ter m in a l P la tin u m (II) P er flu or oa cyl P h osp h id o
Com p lexes: Syn th esis a n d Dyn a m ic P r ocesses
Denyce K. Wicht and David S. Glueck*
Department of Chemistry, Dartmouth College, 6128 Burke Laboratory,
Hanover, New Hampshire 03755
Louise M. Liable-Sands and Arnold L. Rheingold
Department of Chemistry, University of Delaware, Newark, Delaware 19716
Received May 18, 1999
The Pt(II) phosphido methyl complexes Pt(dppe)(Me)(PPhR) (dppe ) Ph2PCH2CH2PPh2,
R ) i-Bu, 1; R ) Is ) 2,4,6-(i-Pr)3C6H2, 2) have been prepared by proton transfer from
secondary phosphines to the methoxide ligand of Pt(dppe)(Me)(OMe). Oxidative addition of
ClC(O)C3F7 to Pt(PPh2Me)4 gives trans-Pt(PPh2Me)2(COC3F7)(Cl) (3); treatment of 3 with
dppe yields Pt(dppe)(COC3F7)(Cl) (4). Complexes 3‚0.5CH2Cl2 and 4 were structurally
characterized by X-ray crystallography. Reaction of 4 with AgBF4 and a secondary phosphine
or treatment of [Pt(dppe)(COC3F7)(NCMe)][BF4] (5) with a secondary phosphine gives the
cations [Pt(dppe)(COC3F7)(PHPhAr)][BF4] (Ar ) Mes ) 2,4,6-Me3C6H2, 6; Ar ) o-anisyl, 7;
Ar ) Is, 8; Ar ) Mes-F9 ) 2,4,6-(CF3)3C6H2, 9; Ar ) Ph, 10). Deprotonation of the cations
with LiN(SiMe3)2 affords the phosphido complexes Pt(dppe)(COC3F7)(PPhAr) (Ar ) Mes,
11; Ar ) o-anisyl, 12; Ar ) Is, 13; Ar ) Mes-F9, 14; Ar ) Ph, 15). Fluxional processes in
complexes 11-15 were studied by variable-temperature multinuclear NMR spectroscopy;
the spectra are consistent with rapid phosphorus inversion on the NMR time scale at room
temperature.
In tr od u ction
are present, these exhibit different NMR chemical shifts
if inversion is slow on the NMR time scale, and rapid
inversion at phosphorus makes them equivalent. For
example, Malisch obtained a phosphido inversion bar-
rier of 14.4 kcal/mol in W(Cp)(CO)2(PMe3)(P(i-Pr)2) by
analysis of the dynamic 1H NMR behavior of the
isopropyl methyl groups.1e Here we report variable-
temperature NMR studies of the complexes Pt(dppe)-
(R)(PPhR′), which contain diastereotopic nuclei either
in a phosphido substituent or in a perfluoroacyl group
coordinated to platinum.
Pyramidal inversion at phosphorus in metal phos-
phido complexes is rapid on the NMR time scale.1 This
process has been studied in complexes containing two
chiral centers; fast exchange gives an averaged NMR
spectrum, and signals due to the two different diaster-
eomers are observed when exchange is slow at low
temperature.1a,b,d,i In the accompanying article, for
example, we report NMR data characterizing rapid
inversion at phosphorus in the chiral platinum(II)
phosphido complexes Pt(diphos)(R)(PR′R′′).2 A disad-
vantage of this approach is that one diastereomer may
be so much higher in energy than the other that it is
not observed, so the barrier to the dynamic process
cannot be measured experimentally. To avoid this
problem, phosphorus inversion can be studied in com-
plexes with one chiral center. If two diastereotopic nuclei
Resu lts a n d Discu ssion
The phosphido methyl complexes Pt(dppe)(Me)(PPhi-
Bu) (1) and Pt(dppe)(Me)(PPhIs) (Is ) 2,4,6-(i-Pr)3C6H2,
2), which contain diastereotopic i-Bu and i-Pr Me
groups, respectively, were prepared by proton transfer
from secondary phosphines to the methoxide ligand of
(1) For examples, see: (a) Zwick, B. D.; Dewey, M. A.; Knight, D.
A.; Buhro, W. E.; Arif, A. M.; Gladysz, J . A. Organometallics 1992, 11,
2673-2685. (b) Buhro, W. E.; Zwick, B. D.; Georgiou, S.; Hutchinson,
J . P.; Gladysz, J . A. J . Am. Chem. Soc. 1988, 110, 2427-2439. (c)
Simpson, R. D.; Bergman, R. G. Organometallics 1992, 11, 3980-3993.
(d) Crisp, G. T.; Salem, G.; Wild, S. B.; Stephan, F. S. Organometallics
1989, 8, 2360-2367. (e) Malisch, W.; Maisch, R.; Meyer, A.; Greiss-
inger, D.; Gross, E.; Colquhoun, E. J .; McFarlane, W. Phosphorus
Sulfur 1983, 18, 299-302. (f) Baker, R. T.; Whitney, J . G.; Wreford,
S. S. Organometallics 1983, 2, 1049-1051. (g) Bonnet, G.; Kubicki,
M. M.; Moise, C.; Lazzaroni, R.; Salvadori, P.; Vitulli, G. Organome-
tallics 1992, 11, 964-967. (h) Fryzuk, M. D.; J oshi, K.; Chadha, R. K.;
Rettig, S. J . J . Am. Chem. Soc. 1991, 113, 8724-8736. (i) Malisch, W.;
Gunzelmann, N.; Thirase, K.; Neumayer, M. J . Organomet. Chem.
1998, 571, 215-222. (j) For a review, see: Rogers, J . R.; Wagner, T.
P. S.; Marynick, D. S. Inorg. Chem. 1994, 33, 3104-3110.
1
Pt(dppe)(Me)(OMe).3 The H NMR spectrum (toluene-
d8) of previously reported4 1 at room temperature
exhibits a doublet (3J HH ) 6 Hz, 6H) at δ 0.99, assigned
to the i-Bu Me groups. This signal decreases in intensity
and broadens to a single peak as the temperature is
decreased to -15 °C. At -50 °C, two broad peaks begin
to grow in, but they do not sharpen as the temperature
is further decreased to -70 °C. These inconclusive
(3) Bryndza, H. E.; Calabrese, J . C.; Wreford, S. S. Organometallics
1984, 3, 1603-1604.
(4) Wicht, D. K.; Paisner, S. N.; Lew, B. M.; Glueck, D. S.; Yap, G.
P. A.; Liable-Sands, L. M.; Rheingold, A. L.; Haar, C. M.; Nolan, S. P.
Organometallics 1998, 17, 652-660.
(2) Wicht, D. K.; Kovacik, I.; Glueck, D. S.; Liable-Sands, L. M.;
Incarvito, C. D.; Rheingold, A. L. Organometallics 1999, 18, 5141.
10.1021/om9903691 CCC: $18.00 © 1999 American Chemical Society
Publication on Web 11/22/1999

Terminal Pt(II) Perfluoroacyl Phosphido Complexes
Organometallics, Vol. 18, No. 24, 1999 5131
Sch em e 1
observations were further complicated by the overlap
of this methyl signal with that of the Pt-Me group (m,
δ 1.06-0.98).
The 13C{1H} NMR spectrum of phenyl(isobutyl)-
phosphine shows two signals due to the diastereotopic
3
Me carbons at δ 24.2 and 24.1 (C6D6); each exhibits J PC
) 8 Hz. In contrast, in the 13C{1H} NMR spectrum of 1
(C6D6), the Me signal appears as a doublet (3J PC ) 7
Hz) at δ 25.2. This could be due either to rapid inversion
at phosphorus or to the two diastereotopic Me groups
having the same chemical shifts. Further study of 1 was
hampered by its rapid decomposition in solution.
Diarylphosphido complex 2, an orange-yellow solid,
is stable in solution and has a 31P NMR spectrum
similar to those of previously reported Pt(dppe)(Me)-
glets. The CdO stretch observed in the IR (KBr)
spectrum at 1672 cm-1 is similar to those reported for
Pt(PPh2Me)2(COCF3)(Cl) (1670 cm-1) and Pt(PPh2Me)2-
(COC2F5)(Cl) (1675 cm-1).7 IR data for the perfluoroacyl
derivatives 4-15 (see below) are similar.
The X-ray crystal structures of 3‚0.5CH2Cl2 and 4 are
shown in Figures 1 and 2, respectively; selected bond
lengths and angles are given in the figure captions. The
crystallographic data are given in Table 3, and further
details are in the Experimental Section and the Sup-
porting Information.
1
(PRR′) complexes.4 In the H NMR spectrum (toluene-
d8) at room temperature, the signal for the ortho i-Pr
Me groups is a doublet (3J HH ) 7 Hz, 12H) at δ 1.21;
the same chemical shift and coupling constant are
observed for these protons in the 1H NMR spectrum
(C6D6) of the free phosphine PHPhIs.5 This signal in 2
broadens as the temperature is lowered and begins to
decoalesce into two peaks at -35 °C. However, at lower
temperatures, all the 1H NMR signals become broad and
complete decoalescence is indiscernible.
The crystal structure of 3 shows the expected square
planar geometry at platinum; the angles around the
metal center range from 89.70(6)° to 90.6(2)°. The
structure is similar to that of the related complex trans-
Pt(PPh2Me)2(COCF3)(Cl).8 The Pt-Cl, Pt-C(O), and
carbonyl bond lengths for 3 (2.402(2), 1.990(7), and
1.191(9) Å, respectively) are the same within experi-
mental error as those in the trifluoroacyl complex
(2.390(1), 2.028(6), and 1.210(5) Å). The Pt-P bond
lengths are slightly longer in 3 (2.332(2) and 2.338(2)
Å) than in the trifluoroacyl complex (2.316(1) and 2.321-
(1) Å), although the difference is small.
The structure of 4 shows a slightly distorted square
planar geometry due to the P-Pt-P bite angle of 85.71-
(3)° imposed by the dppe ligand. The Pt-Cl bond in 4
(2.3774(10) Å) is slightly shorter than the Pt-Cl bond
in 3 (2.402(2) Å), consistent with a larger trans influence
for the perfluoroacyl ligand than for the phosphine. The
Pt-C(O) and carbonyl bond lengths in 4 are 2.051(3)
and 1.221(4) Å, respectively. The Pt-phosphine bond
lengths are 2.3525(9) Å for the P trans to COC3F7 and
2.2431(9) Å for the P trans to Cl; these results and the
1J Pt-P values suggest that the perfluoroacyl ligand has
a greater trans influence than Cl.
Treatment of 4 with AgBF4 generates the acetonitrile
cation [Pt(dppe)(COC3F7)(NCMe)][BF4] (5) (Scheme 2),
whose 31P NMR spectrum is similar to that of the
previously reported methyl complex [Pt(dppe)(Me)(NC-
Me)][BF4].9 The cationic complexes [Pt(dppe)(COC3F7)-
(PHPhAr)][BF4] (Ar ) Mes ) 2,4,6-(Me)3C6H2, 6; Ar )
o-anisyl, 7; Ar ) Is, 8; Ar ) Mes-F9 ) 2,4,6-(CF3)3C6H2,
9; Ar ) Ph, 10) were prepared by treatment of 5 with
the appropriate phosphine or directly from 4 (Scheme
2). The 31P NMR spectra of 6-10 (Table 1) exhibit the
expected AMX patterns with the resonances due to the
coordinated phosphines appearing upfield between δ -7
In the 13C{1H} NMR spectrum (toluene-d8), the o-i-
Pr Me signal is a sharp singlet at δ 25.7. At -15 °C,
the 31P NMR signals for the dppe phosphorus trans to
the methyl and for the phosphido ligand become broad
and low in intensity. This broadening continues until
-70 °C, when both signals completely disappear into
the baseline.6 However, at this temperature, the signal
for the dppe phosphorus trans to the phosphido ligand
remains sharp and neither the chemical shift nor the
coupling constants change.
The NMR observations in 1 and 2 are consistent with
rapid inversion at phosphorus, but could also be ex-
plained if the diastereotopic Me groups have coincident
chemical shifts. Therefore, to exploit the larger chemical
1
shift dispersion of 19F NMR in comparison to H NMR
spectra, we prepared complexes containing diaste-
reotopic CF2 groups.
Bennett and co-workers previously reported oxidative
addition of ClC(O)CF3 and ClC(O)C2F5 to Pt(PPh2Me)4.7
A similar reaction with the perfluoropropyl analogue
gives trans-Pt(PPh2Me)2(COC3F7)(Cl) (3). Addition of
dppe to a solution of 3 gives the cis compound Pt(dppe)-
(COC3F7)(Cl) (4) (Scheme 1). 31P and 19F NMR data for
4 and its derivatives 5-15 (see below) are given in
Tables 1 and 2.
The 31P NMR spectrum of 3 (CDCl3) shows a triplet
at δ 6.5 (2J PF ) 5 Hz, 1J Pt-P ) 2916 Hz). In the 19F NMR
spectrum (CDCl3), the signal for the CF3 group is a well-
resolved triplet at δ -81.2 with F-F coupling of 9 Hz.
Under some conditions, the CF2 resonances in this and
the subsequent compounds are multiplets (δ -111.5 to
-111.6 (COCF2) and δ -127.6 to -127.7 (CF2CF3) for
3). However, we usually observed them as broad sin-
(5) Brauer, D. J .; Bitterer, F.; Do¨rrenbach, F.; Hebler, G.; Stelzer,
O.; Kru¨ger, C.; Lutz, F. Z. Naturforsch. 1996, 51B, 1183-1196.
(6) The accompanying article (ref 2) reports similar observations for
Pt(S,S-Chiraphos)(Me)(PPhIs). We assume that the unusual broadness
observed in the 31P NMR spectrum is due to a dynamic process
involving rotation around the Pt-PPhIs bond (see below).
(7) Bennett, M. A.; Chee, H.-K.; Robertson, G. B. Inorg. Chem. 1979,
18, 1061-1070.
(8) Bennett, M. A.; Ho, K.-C.; J effery, J . C.; McLaughlin, G. M.;
Robertson, G. B. Aust. J . Chem. 1982, 35, 1311-1321.
(9) In CDCl3, δ 49.1 (1J Pt-P ) 1809 Hz, P trans to Me) and δ 38.9
(1J Pt-P ) 4370, P trans to NCMe). Appleton, T. G.; Bennett, M. A. Inorg.
Chem. 1978, 17, 738-747.

5132 Organometallics, Vol. 18, No. 24, 1999
Ta ble 1. 31P NMR Da ta for [P t(d p p e)(COC3F 7)(X)]n + Com p lexesa -d
Wicht et al.
X
no.
δ(P1) (J Pt-P
)
δ(P2) (J Pt-P
)
δ(P3) (J Pt-P
)
J 12
J 13
J 23
Cl
NCMe
4
5
6
7
8
9
10
11
12
12a
12b
13
13a
13b
14
34.8 (3931)
30.6 (4087)
46.6 (2695)
47.5 (2207)
40.7 (2682)
44.3 (2942)
48.2 (2713)
46.3 (1869)
47.2 (1898)
49.3 (1950)
47.5 (1877)
41.0 (1865)
46.8 (1920)
36.4 (1755)
42.1 (1755)
42.3 (1688)
44.2 (1627)
40.0 (1634)
41.8 (1622)
44.7 (1631)
39.9 (1865)
42.3 (1782)
43.5 (1759)
45.6 (1798)
31.6 (1836)
30.5 (1830)
8
8
9
10
9
10
9
PH(Ph)(Mes)
PH(Ph)(o-An)
PH(Ph)(Is)
PH(Ph)(Mes-F9)
PHPh2
-33.0 (2524)
-21.3 (2672)
-31.5 (2554)
-12.2 (2724)
-7.9 (2576)
-14.0 (949)
-28 (v. broad)
-22.4 (1103)
-39.6 (880)
-28.4 (989)
-27.2 (1060)
-25.6 (broad)
4.0 (1096)
306
314
305
325
304
107
86
24
24
23
21
22
5
P(Ph)Mes)
P(Ph)(o-An)
(-50 °C)
8
9
99
82
(1.3:1 ratio)e
P(Ph)(Is)
106
112
102
111
111
92
(-70 °C)
(1.7:1 ratio)a
P(Ph)(Mes-F9)
(-70 °C)
39.9 (broad)
39.5 (2100)
39.4 (2096)
45.7 (1880)
38.7 (broad)
33.5 (1743)
29.7 (1717)
42.3 (1816)
-6.5 (1060)
-1.6 (894)
PPh2
15
11
12
a
n ) 0 for 4 and 11-15; n ) 1 for 5-10. bTemperature ) 22 °C except where noted. Chemical shifts in ppm, external reference 85%
H3PO4, coupling constants in Hz. P1 and P2 are the dppe P nuclei; P3 is trans to P1. dSolvents: CD2Cl2 for 4, 6, 7, 9, 10; CDCl3 for 5, 8;
THF-d8 for 11, 12, 15; toluene-d8 for 13, 14. Labels: major isomer a , minor isomer b.
c
e
Ta ble 2. 19F NMR Da ta for [P t(d p p e)(COC3F 7)(X)]n + Com p lexesa ,b,c
X
no.
δ(CF3)d
δ(COCF2) (J FF
)
δ(CF2CF3) (J FF)
Cl
NCMe
4
5
6
7
8
9
10
11
-81.6
-81.2
-81.6
-81.7
-81.5
-79.1
-81.6
-82.6
-82.6
-82.0
-82.0f
-112.9 to -113.0 (m)
-114.4
-126.5 to -126.6 (m)
-127.0
PH(Ph)(Mes)
PH(Ph)(o-An)
PH(Ph)(Is)
-112.6
-127.4
-112.6, -114.2 (314)
-111.5, -112.5 (307)
-109.8 (broad)
-113.2
-112.9
-111.5, -114.4 (308)
-113.2
-114.9, -117.1 (306)
-114.0, -115.3 (313)
-112.2
-127.5 to -127.6 (m)
-126.6, -127.5 (300)
-124.5
PH(Ph)(Mes-F9)e
PHPh2
-127.3
P(Ph)(Mes) (70 °C)
(-15 °C)
P(Ph)(o-An) (60 °C)
(-50 °C)
(1.3:1 ratio)
P(Ph)(Is) (60 °C)
(-70 °C)
(1.7:1 ratio)
P(Ph)(Mes-F9) (60 °C)
(-70 °C)
(5:1 ratio)
PPh2
-127.7
-127.7
12
-127.1
12a
12b
13
13a
13b
14
14a
14b
15
-128.6, -129.9 (310)
-129.4
-81.2
-126.7
-81.2f
-112.4, -115.3 (310)
-111.6 to -112.1 (m)
-111.8
-127.4 (broad)
-127.1 (broad)
-126.8
-81.3
-81.6
-81.1
-81.4
-81.4
-111.7 (broad m)
-127.0, -128.6 (300)
-112.2
-112.9, -113.9 (308)
-126.7
-127.9, -128.9 (308)
(-40 °C)
a
n ) 0 for 4 and 11-15; n ) 1 for 5-10. For cations 5-10, an additional peak due to the BF4 anion was observed near -153 ppm.
Temperature ) 22 °C except where noted. Chemical shifts in ppm, external reference CFCl3, coupling constants in Hz. c Solvents:
b
d
CD2Cl2 for 4, 6, 7, 9, 10; CDCl3 for 5, 8, THF-d8 for 11, 12, 15; toluene-d8 for 13, 14. The CF3 signals are triplets with J FF values of 9-10
Hz. e Additional data for Mes-F9 derivatives: for 9 δ -53.2 (d, 4J FP ) 12, o-CF3), -61.8 (p-CF3); for 14 δ -55.5 (d, 4J PF ) 42, o-CF3), -63.6
(p-CF3). For 14 at -70 °C, see text, and δ -56.8 (broad), -63.2 and -62.9 (5:1 ratio, p-CF3). f Different CF3 resonances were not observed
for the two isomers.
2
1
and -33. The large J PP(trans) (304-325 Hz), J Pt-P
plexes Pt(dppe)(COC3F7)(PPhAr) (Ar ) Mes, 11; Ar )
o-anisyl, 12; Ar ) Is, 13; Ar ) Mes-F9, 14; Ar ) Ph, 15)
(Scheme 2). These yellow or orange solids were charac-
terized by NMR (1H, 31P, 19F) spectroscopy, IR spectros-
copy, and elemental analysis. They are stable in the
solid state, but decompose slowly in solution to uniden-
tified products. The phosphido resonances are observed
in the 31P NMR spectra from δ 4.0 to -28.4 (Table 1).
The signal due to the phosphido ligand in 14 is very
broad, presumably as a consequence of P-F coupling
to the ortho CF3 groups of Mes-F9. As expected, the
observed P-P(trans) couplings (∼90-120 Hz) and Pt-P
couplings (∼900-1100 Hz) are small in comparison to
those of the coordinated phosphine precursors 6-10,
because of decreased s-character in the Pt-phosphido
bond upon deprotonation.10
1
(2500-2700 Hz), and J PH (388-410 Hz) are character-
istic of cationic Pt(II) phosphine complexes.9 The signal
for the coordinated phosphine PHPhMes-F9 in 9 is quite
broad, presumably due to P-F coupling.
The presence of a chiral phosphorus center in 6-9
makes the fluorine atoms of the CF2 groups diaste-
reotopic. However, due to accidental chemical shift
equivalence in 6 and 9, the perfluoroacyl ligands in
these complexes show only three signals, with chemical
shifts and F-F coupling constants similar to those for
3-5 (Table 2). As expected, a similar 19F NMR spectrum
is observed for 10, because the phosphido ligand is
symmetric. In the case of 7 and 8, however, the CF2
fluorine signals are AB patterns that exhibit F-F
coupling. In 8, the ortho i-Pr Me groups are diaste-
3
reotopic; two signals appear at δ 0.95 (d, J HH ) 7 Hz,
6H) and 0.76 (broad, 6H).
Deprotonation of the cationic complexes 6-10 with
LiN(SiMe3)2 affords the neutral Pt(II) phosphido com-
Va r ia ble-Tem p er a tu r e NMR Beh a vior . As in the
cationic precursors, the chiral phosphorus centers in
11-14 make the fluorines in the CF2 groups diaste-
reotopic, as observed in variable-temperature 19F NMR

Terminal Pt(II) Perfluoroacyl Phosphido Complexes
Organometallics, Vol. 18, No. 24, 1999 5133
Ta ble 3. Cr ysta llogr a p h ic Da ta for
tr a n s-P t(P P h 2Me)2(COC3F 7)(Cl) (3)‚0.5CH2Cl2 a n d
P t(d p p e)(COC3F 7)(Cl) (4)
3‚0.5CH2Cl2
4
formula
fw
C
30.5H27Cl2F7OP2Pt
C30H24ClF7OP2Pt
825.97
870.45
space group
a, Å
b, Å
P1h
P21/n
10.1465(2)
12.2675(2)
15.0834(3)
102.9967(6)
100.4318(9)
114.3832(6)
1584.85(3)
2
9.2231(2)
27.2944(4)
12.4868(3)
90
104.8681(8)
90
c, Å
R, deg
â, deg
γ, deg
V, Å3
3038.18(3)
4
Z
cryst color, habit
D(calc), g cm-3
µ(Mo KR), cm-1
temp, K
diffractometer
radiation
R(F), %a
R(wF2), %a
colorless rod
1.824
47.62
pale yellow rod
1.806
48.78
223(2)
198(2)
Siemens P4/CCD
F igu r e 1. ORTEP diagram of 3‚0.5CH2Cl2 with thermal
ellipsoids at 30% probability. Solvent molecule and hydro-
gen atoms are omitted for clarity. Selected bond lengths
(Å) and angles (deg): Pt-C(1) ) 1.990(7), Pt-Cl(1) ) 2.402-
(2), Pt-P(31) ) 2.338(2), Pt-P(11) ) 2.332(2), C(1)-O(1)
) 1.191(1), C(1)-Pt-P(11) ) 90.6(2), P(11)-Pt-Cl(1) )
89.7(6), Cl(1)-Pt-P(31) ) 89.95(7), P(31)-Pt-C(1) ) 90.0-
(2), P(11)-Pt-P(31) ) 173.23(5), C(1)-Pt-Cl(1) ) 177.6-
(2).
Mo KR (λ ) 0.71073 Å)
4.27
2.80
5.87
14.49
Quantity minimized ) R(wF2) ) ∑[w(Fo2 - Fc2)2/∑[(wFo2)2]1/2
R ) ∑∆/∑(Fo), 4 ) |(Fo - Fc)|
;
a
Sch em e 2
signal broadening was observed at -70 °C. The 31P
NMR peaks for 11 remain sharp from 60 to -15 °C; they
broaden slightly at -35 °C and continue to decrease in
F igu r e 2. ORTEP diagram of 4 with thermal ellipsoids
at 30% probability and hydrogen atoms omitted for clarity.
Selected bond lengths (Å) and angles (deg): Pt-C(3) )
2.051(3), Pt-Cl(1) ) 2.3774(10), Pt-P(1) ) 2.3525(9), Pt-
P(2) ) 2.2431(9), C(3)-O(3) ) 1.221(4), C(3)-Pt-P(2) )
92.32(10), P(2)-Pt-P(1) ) 85.71(3), P(1)-Pt-C(1) ) 96.18-
(3), Cl(1)-Pt-C(3) ) 85.89(1), C(3)-Pt-P(1) ) 176.72(10),
P(2)-Pt-Cl(1) ) 177.10(3).
1
intensity as the temperature reaches -70 °C. In the H
NMR spectra (THF-d8), the sharp singlet observed for
the two aryl o-Me groups at δ 2.44 (22 °C, 6H) does not
broaden into the baseline until -70 °C, an indication
that rotation around the P-C(Mes) bond does not
appear to be restricted at lower temperatures.
spectra (Table 2). In some cases, variable-temperature
Similar 19F NMR decoalescence behavior resulting in
AB quartets was observed at -50 °C for Pt(dppe)-
(COC3F7)(PPho-anisyl) (12); in addition, two different
isomers (1:1.3 ratio) were observed at this temperature
by 19F and 31P NMR (Tables 1 and 2 and Figure 3).
1
31P and H NMR spectra provided additional informa-
tion about the dynamics of these molecules in solution.
For example, the 19F NMR spectrum (THF-d8) of Pt-
(dppe)(COC3F7)(PPhMes) (11) at 60 °C contains sharp
signals due to the CF3 and CF2CF3 groups, but a broad
COCF2 resonance. At room temperature this signal
decoalesces into two peaks, and at -15 °C it is an AB
quartet (2J FF ) 308 Hz) which continues to sharpen as
the temperature is lowered to -50 °C. Some additional
1
Variable-temperature H NMR spectra are consistent
with the 19F and 31P NMR results. At room temperature
in the 1H{31P} NMR spectrum (THF-d8), the OMe signal
is a singlet at δ 3.85; at -50 °C the peak decoalesces
into two peaks at δ 4.01 and 3.82 in a 1.3:1 ratio.
The variable-temperature NMR spectra of Pt(dppe)-
(COC3F7)(PPhIs) (13) are similar to those of 12; at low
temperature there is a 1.7:1 ratio of isomers (Tables 1
and 2). This behavior is also observed in the 1H{31P}
(10) (a) Bohle, D. S.; J ones, T. C.; Rickard, C. E. F.; Roper, W. R.
Organometallics 1986, 5, 1612-1619. (b) Deeming, A. J .; Doherty, S.;
Marshall, J . E.; Powell, J . L.; Senior, A. M. J . Chem. Soc., Dalton Trans.
1993, 1093-1100. (c) Handler, A.; Peringer, P.; Mu¨ller, E. P. J . Chem.
Soc., Dalton Trans. 1990, 3725-3727. (d) Ref 1b.

5134 Organometallics, Vol. 18, No. 24, 1999
Wicht et al.
F igu r e 3. Variable-temperature 31P{1H} NMR spectra
(THF-d8) of Pt(dppe)(COC3F7)(PPho-anisyl) (12) at the
following temperatures: 60 °C (top), 22 °C, -15 °C, -34
°C, -50 °C (bottom).
NMR spectra of 13 (toluene-d8). As in complex 2, the
ortho i-Pr Me groups give rise to a broad doublet at δ
3
1.19 (12H, J HH ) 6 Hz) and a methine signal (m, δ
4.72-4.67). Both of these signals as well as the dppe
CH2 and aryl proton peaks broaden as the temperature
is lowered. At -50 °C two new methine peaks begin to
grow in, and at -70 °C the signals are broad and in a
ratio of approximately 1.7:1 (δ 5.03 and 4.69).
F igu r e 4. Variable-temperature 19F NMR spectra (THF-
d8) of Pt(dppe)(COC3F7)(PPh2) (15) at the following tem-
peratures: 25 °C (top), 12 °C, -5 °C, -25 °C, -40 °C, -60
°C, -70 °C (bottom).
The variable-temperature NMR data for the PPhMes-
F9 analogue (14) is somewhat more complicated because
of the presence of the bulky Mes-F9 group. At -15 °C,
the signal for its equivalent ortho CF3 groups decoa-
lesces into two peaks at δ -54.8 and -56.2, presumably
due to restricted rotation around the P-C(Mes-F9) bond,
and the two CF2 resonances also broaden and split into
two peaks at δ -111.6 and -112.0 (COCF2) and δ
-127.0 and -127.2 (CF2CF3). The 19F NMR spectrum
at -70 °C is complicated (Table 2). One of the two peaks
due to the ortho CF3 group splits; it is unclear if these
are two different peaks at δ -54.1 and -54.4 or simply
P-F coupling of 77 Hz. The other peak due to the ortho
CF3 group is slightly broad. Decoalesence into two peaks
of different intensities (ca. 1:5) is also seen for the para
CF3 signal and the CF2CF3 group. The R CF2 signal is
a broad multiplet, and the â CF2 resonance is an
apparent AB quartet. The low-temperature 31P NMR
spectra, however, do not differ much from those at room
These peaks start to broaden at -5 °C and coalesce into
one broad peak at -22 °C. The broad peak becomes
sharper at lower temperatures; at -60 °C there are
three signals at δ 2.64-2.60 (1H), 2.40-2.36 (1H), and
1
2.08-2.04 (2H) in the H{31P} NMR spectrum.
Measurement of the coalescence temperatures in the
multinuclear NMR spectra of these complexes provides
approximate free energies of activation for the dynamic
processes.11 The results are shown in Table 4. There is
good agreement between data obtained from spectra of
different nuclei, and the barriers (ca. 11-13 kcal/mol)
are similar in this series of perfluoroacyl complexes.
Dyn a m ic P r ocesses. The perfluoroacyl groups in
phosphido complexes 11-14 were intended to serve as
19F NMR spectroscopic probes of phosphorus inversion.
As described briefly in the Introduction, the diaste-
reotopic fluorine nuclei in a CF2 group are expected to
have different NMR chemical shifts if inversion is slow
on the NMR time scale, while rapid phosphorus inver-
sion through a planar transition state makes them
equivalent. As foreseen, the 19F NMR signals due to the
CF2 groups in these compounds are singlets in the high-
1
temperature (Table 1), and H NMR spectra were not
particularly informative.
As shown in Figure 4, the low-temperature 19F NMR
spectra of the higher-symmetry complex Pt(dppe)-
(COC3F7)(PPh2) (15) are similar to those observed for
11-14, with AB quartet signals observed for both CF2
groups at -40 °C. The 31P spectrum does not change at
this temperature. The dppe CH2 protons appear as two
(11) Friebolin, H. In Basic One- and Two-Dimensional NMR Spec-
troscopy, 2nd ed.; VCH: New York, 1993; pp 287-314. See the
Experimental Section for more details and error analysis.
1
multiplets at δ 2.32-2.30 and δ 2.18-2.13 in the H-
{31P} NMR spectrum (THF-d8) at room temperature.

Terminal Pt(II) Perfluoroacyl Phosphido Complexes
Organometallics, Vol. 18, No. 24, 1999 5135
Ta ble 4. Va r ia ble-Tem p er a tu r e NMR Da ta for
P er flu or oa cyl P t(II) P h osp h id o Com p lexesa
Ch a r t 1
q
∆ν
J AB
∆Gc
complex
resonanceb
(Hz)c
(Hz)d
Tc (K)
(kcal/mol)
11
12
COCF2
818
367
621
367
2089
219
255
57
308
313
306
310
295
253
253
263
283
243
243
243
278
263
263
12.7
10.9
10.9
11.4
11.8
11.1
11.1
11.8
11.9
11.4
11.4
COCF2 (a)
COCF2 (b)
CF2CF3
PPh(o-An)
cis dppe P
trans dppe P
OMe
COCF2
COCF2
CF2CF3
13
15
818
282
282
310
308
308
a
Solvent: THF-d8 for 11, 12 and 15, toluene-d8 for 13.
Estimated errors are different for each resonance; the largest
estimated errors are on the order of 5 Hz in ∆ν and J AB, 10 °C in
q
Tc, and 0.5 kcal/mol in ∆Gc . Cis and trans are defined with respect
to the phosphido ligand. bThe italics indicate 19F, 31P, or 1H nuclei.
c4ν values from slow-exchange spectra at 248 K (11), 223 K (12),
d
203 K (13 and 15). J FF in CF2 from slow-exchange 19F NMR
spectra.
temperature limit, consistent with rapid inversion at
phosphorus. In the low-temperature spectra, AB quar-
tets are observed for the fluorine signals, consistent with
slow inversion on the NMR time scale. The barriers
calculated for these dynamic processes, ca. 11-13 kcal/
mol, are similar to those reported for phosphorus
inversion in other transition metal phosphido com-
plexes.1
However, the observation of singlet resonances in the
high-temperature 19F NMR spectra might be due to
accidental chemical shift equivalence of the diaste-
reotopic CF2 fluorine nuclei, as observed in the 19F NMR
spectra of two of the four cations (6 and 9). In this case,
the low-temperature observations of inequivalent fluo-
rines must be explained not by slow inversion, but by a
different fluxional process.
Several dynamic processes could give rise to the
observed 19F NMR AB patterns. It is convenient to
discuss each in terms of the highest symmetry confor-
mation possible in these perfluoroacyl phosphido com-
plexes, in which a plane of symmetry lies in the square
plane of the molecule. The diastereotopic fluorines in a
CF2 group are equivalent in the high-symmetry confor-
mation when the carbonyl group is in the square plane
and the fluorine nuclei of each CF2 group are positioned
above and below the plane. This perfluoroacyl geometry
should be accessible on the NMR time scale unless there
is restricted rotation about the Pt-C or C-C bond,
which seems unlikely, given the ca. 4 kcal/mol rotational
barrier in C2F6.12
Slow interconversion between the two isomers (δ and
λ) that are possible due to different dppe ring conforma-
tions (Chart 1) could remove the effective (square) plane
of symmetry and make the fluorines of a CF2 group
inequivalent. However, literature reports suggest that
the barrier to this process is lower than the ones we
observe. Thus, δ-λ interconversion in the ruthenium
complexes [Ru(Cp)(dppe)(SR2)]+ (R ) Ph, Et; Chart 1,
A) was found to have a barrier less than ca. 7 kcal/mol.13
Similarly, Deeming and Doherty rejected δ-λ intercon-
version as a possible dynamic process to account for the
low-temperature 31P NMR observations in meso-Pt-
(dppe)(µ-PPhH)2{Mo(CO)5}2 (B, Chart 1).14 For example,
the analogous complex Pt(Ph2PCHdCHPPh2)(µ-PPhH)2-
{Mo(CO)5}2 (C, Chart 1) exhibited similar fluxional
behavior, although δ-λ interconversion is impossible
with this rigid ligand. Consistent with these precedents,
no evidence of dynamic behavior was found in the low-
temperature 19F NMR spectrum of Pt(dppe)(COC3F7)-
(Cl) (4).
The 31P NMR observations on B and C were ascribed
to restricted rotation around the Pt-µ-P bond. This
conclusion was supported by the lack of dynamic
behavior observed in Pt(dppe)(µ-PPhH)2{Mo(CO)4} (D,
Chart 1), where the single Mo center bridges the two
phosphido ligands, thereby restricting rotation around
the Pt-µ-P bonds. Hindered rotations similar to those
observed in B and C have been observed in related
complexes containing M-µ-PR2 ligands.15
Similar slow rotation about Pt-P bonds may be
occurring at low temperature in phosphido complexes
11-15. In the perfluoroacyl complex with the highest
symmetry, diphenylphosphido compound 15, the fluo-
rine nuclei of a CF2 group can become equivalent at high
temperature by rotation about the Pt-P bond; the
phosphorus phenyl groups become equivalent when the
P lone pair is in the square plane. Phosphorus inversion
can also make the fluorines equivalent via the transition
state in which the PC2 unit is either coplanar with or
perpendicular to the Pt square plane. Note that this
requires Pt-P rotation to be unhindered so that the
planar phosphido group can occupy the square plane of
symmetry. The low-temperature 19F NMR results for
(14) Deeming, A. J .; Doherty, S. Polyhedron 1996, 15, 1175-1190.
(15) (a) Deeming, A. J .; Cockerton, B. R.; Doherty, S. Polyhedron
1997, 16, 1945-1956. (b) Dobbie, R. C.; Mason, P. R. J . Chem. Soc.,
Dalton Trans. 1976, 189-191. (c) Maassarani, F.; Davidson, M. F.;
Wehman-Ooyevaar, I. C. M.; Grove, D. M.; van Koten, M. A.; Smeets,
W. J . J .; Spek, A. L.; van Koten, G. Inorg. Chim. Acta 1995, 235, 327-
338.
(12) Gallaher, K. L.; Yokozeki, A.; Bauer, S. H. J . Phys. Chem. 1974,
78, 2389-2395.
(13) Ohkita, K.; Kurosawa, H.; Hirao, T.; Ikeda, I. J . Organomet.
Chem. 1994, 470, 179-182.

5136 Organometallics, Vol. 18, No. 24, 1999
Wicht et al.
15 thus require that both Pt-P rotation and P inversion
be slow on the NMR time scale at low temperature.16
Since the aryl groups in unsymmetrical phosphido
complexes 11-14 are bulkier than phenyl, it is likely
that Pt-P(Ph)(Ar) rotation is also slow on the NMR time
scale at low temperature for those compounds.17 In these
cases, inversion at phosphorus can make the fluorines
of a CF2 group equivalent only if the planar PC2 unit of
the phosphido group can occupy the square plane of the
molecule. Thus, if restricted rotation about the Pt-P
bond makes this impossible, rapid inversion may still
occur, but the fluorine nuclei of a CF2 group are
inequivalent. In other words, unlike the situation for
symmetrical PPh2 complex 15, Pt-P rotation alone
cannot make the fluorines of a CF2 group equivalent in
11-14; P inversion is required to do this. Therefore, the
observation in these cases of CF2 singlet resonances in
the 19F NMR spectra at room temperature or above
requires that P inversion is rapid on the NMR time scale
at these temperatures. By extension, this process is also
likely to be rapid for 15 at room temperature, although
we cannot reach this conclusion from the data for 15 in
isolation (that is, P inversion could have a high barrier
for 15, as long as Pt-P rotation was rapid at room
temperature).
With these ideas in mind, it is possible to rationalize
the observed low-temperature spectra of complexes 11-
14. For (o-anisyl)phenylphosphido complex 12, the
simplest explanation (A) for the observation of inequiva-
lent fluorines (19F NMR) and of two different isomers
is that both phosphorus inversion and Pt-P rotation
are slow on the NMR time scale at low temperature. In
this case, the two observed isomers are diastereomers
in which either the P-Ph or the P-anisyl group is close
in space to the perfluoroacyl ligand. These isomers
would be interconverted by a combination of Pt-P
rotation and P inversion. The lack of symmetry of the
anisyl group means that other combinations of dynamic
processes could explain the spectroscopic observations.
First, slow inversion at phosphorus plus slow rotation
about the P-C(anisyl) bond (B) would give two diaster-
eomers that differ in the position of the anisyl group.
Second, slow Pt-P rotation plus slow P-C rotation (C)
could give two analogous isomers, with the proviso (see
above) that the PC2 unit is not in the square plane. Due
to its simplicity and in analogy with 13 and 14 (see
below), we favor explanation A above.
For isityl- and fluoromesitylphosphido complexes 13
and 14, the low-temperature NMR spectra are not as
well-resolved as for 11, 12, and 15. However, in both
these cases, there is evidence for the existence of two
low-temperature diastereomers, as is clear for anisyl
complex 12. As in that case, the simplest explanation
of these observations is that both P inversion and Pt-P
rotation are slow at low temperature. Although the 19F
NMR spectrum at -15 °C shows that rotation about the
P-C(Mes-F9) bond in 14 is slow, the symmetry of the
Mes-F9 group means that this process cannot give rise
to the two isomers seen at this temperature. With these
extremely bulky aryl groups, we cannot, however, rule
out other conformational equilibria which might also
lead to the inequivalence of the CF2 fluorines.
According to these analyses, the dynamic processes
for which barriers were extracted from the NMR spectra
involve a combination of phosphorus inversion and
Pt-P rotation. We cannot determine the relative con-
tributions from each of these processes to the overall
barriers, but we conclude that phosphorus inversion in
these complexes has a maximum barrier of ca. 11-13
kcal/mol. A referee called this conclusion and those of
the accompanying article “intrinsically flawed since the
inversion process is coupled with rotation about the Pt-
PRR′ bond. This arises due to the fact that these
systems contain cis-bidentate diphosphine ligands in a
square-planar array”. However, this problem is not
unique to square planar systems; it also arises in, for
example, octahedral1c and pseudo-tetrahedral (three-
legged piano stool)1a,b phosphido complexes. The referee
also commented that “all of the data are not definitive
unless the assumption that rotation is barrierless is
made”. In our view, the importance of these results is
not the exact value of the phosphorus inversion barriers,
but the fact that they are so much lower than the ones
observed in tertiary phosphines. We cannot determine
if rotation occurs through the pyramidal or the planar
form of the phosphido ligand. It may, however, be
possible to obtain “pure” inversion barriers in related
systems by restricting the rotation of metal phosphido
ligands.
Why are inversion barriers in these platinum(II)
phosphido complexes and the ones reported in the
accompanying article so low? Our previously reported
X-ray structures of platinum(II) phosphido complexes
confirm that the geometry at phosphorus is pyramidal.4
The transition state for pyramidal inversion presumably
includes a trigonal planar phosphido P with a lone pair
in a p-orbital. For inversion barriers to be low, the
energy difference between the planar transition state
and the pyramidal ground state must be relatively
small.
The barrier to pyramidal inversion in tertiary phos-
phines is greatly reduced by the presence of an electro-
positive substituent on phosphorus.18 For example, the
inversion barriers in P(Ph)(i-Pr)(EMe3) (E ) Si, Ge, Sn)
are at least 10 kcal/mol lower than the inversion barrier
in P(Ph)(Me)(CMe3). Mislow and co-workers suggested
that the electropositive Si, Ge, and Sn substituents
increase s-character in the P-E bond, which results in
a concomitant increase in the p-character of the lone
If both P inversion and Pt-P rotation are slow in 11,
13, and 14, we would also expect to see two different
isomers. Therefore, the data for mesitylphosphido com-
plex 11, in which only one isomer is observed, are
puzzling. They could be explained if one of the expected
diastereomers were much higher in energy than the
other, so it is not observed, i.e., if the Mes group is
preferentially oriented close to the perfluoroacyl group.
Alternatively, slow Pt-P rotation, which prevents the
PPh(Mes) group from entering the square plane, would
make the CF2 fluorines inequivalent even if inversion
were fast on the NMR time scale, as discussed for 15.
(16) Alternatively, slow Pt-P rotation, which prevents the PPh2
group from entering the square plane, would make the CF2 fluorines
inequivalent even if inversion were fast on the NMR time scale.
(17) Restricted rotation around the Pt-phosphido bond may also
account for the dynamic process that is apparent in the low-temper-
ature 31P NMR spectrum of Pt(dppe)(Me)(PPhIs) (2).
(18) Baechler, R. D.; Mislow, K. J . Am. Chem. Soc. 1971, 93, 773-
774.

Terminal Pt(II) Perfluoroacyl Phosphido Complexes
Organometallics, Vol. 18, No. 24, 1999 5137
Ch a r t 2
A similar bonding picture has been invoked for iodide-
to-platinum π-bonding in the Pt(II) cation [Pt(P(i-Pr)3)2-
(H)(η1-IPh)][BArf] (Chart 2, BArf ) B(3,5-(CF3)2C6H3)4).22
Kubas and co-workers proposed a π-bonding interaction
between the iodide lone pair in a pz-orbital and a Pt MO
formed by mixing of the filled Pt(dyz) orbital and the
empty Pt(pz) orbital.23 This interaction was proposed to
outweigh the filled Pt(dyz)-iodide lone pair repulsion to
give a net stabilization of about 10 kcal/mol and
overcome steric repulsion between the phenyl and
isopropyl groups, which are unusually close in the solid
state. It was further suggested that the iodide lone pair
electrons are able to interact favorably with Pt(II) p-
and d-orbitals because they are higher in energy than
those of analogous alkoxide, hydroxide, or amido ligands
and are, thereby, better suited for overlap with these
Pt(II) orbitals.
pair. Since the lone pair occupies an orbital of es-
sentially pure p-character in the planar transition state,
the energy difference between the ground state and the
transition state is reduced.19 Although Pt(II) is an
electropositive substituent, our crystallographic and 31P
NMR results are consistent with low s-character in the
Pt-P bonds. This should lead to a high inversion
barrier, due to the rehybridization energy necessary to
reach the sp2 transition state.
Low inversion barriers in early metal transition metal
phosphido complexes are often rationalized in terms of
stabilization of the planar transition state by donation
of the lone pair of electrons to an empty d-orbital on
the metal. For example, the X-ray structure of Hf(Cp)2-
(PEt2)2 shows two distinct bonding modes for the Hf-
PEt2 ligand.1f One is pyramidal with a Hf-PEt2 bond
length of 2.682(1) Å, and the other is planar with a Hf-
PEt2 bond length of 2.488(1) Å. The room-temperature
31P NMR spectra for a series of Hf and Zr complexes
show a singlet, consistent with rapid interconversion of
the pyramidal and planar phosphido ligands, and the
barrier to phosphido interconversion in Hf(Cp)2(PCy2)2
was found to be 6.0 ( 0.2 kcal/mol. A theoretical study
for a series of Ti(IV) phosphido complexes also cites
phosphido to metal π-interaction as an important con-
tribution to stabilization of the planar transition state
in early metal phosphido complexes.1j
However, stabilization of the planar transition state
through interaction of the phosphido lone pair with
d-orbitals on the metal cannot be invoked in these d8
Pt(II) complexes, as the metal d-orbitals of appropriate
symmetry are filled. In fact, compared to other transi-
tion metal phosphido complexes, one might expect Pt-
(II) phosphido complexes to show increased inversion
barriers due to unfavorable interactions between filled
d-orbitals on platinum and the lone pair of electrons on
phosphorus. This type of unfavorable metal-ligand
antibonding π-interaction has been suggested to explain
the lack of terminal oxo complexes of the late transition
metals.20
In our system, a similar interaction between the
phosphorus lone pair and the dyz- and pz-orbitals of Pt-
(II) may be responsible for planar transition state
stabilization and, consequently, the reduced inversion
barriers observed for these perfluoroacyl phosphido
complexes.
Con clu sion
We prepared Pt(dppe)(R)(PPhR′) complexes that con-
tain either diastereotopic methyl groups on the phos-
phido substituent or diastereotopic CF2 fluorines on a
Pt-bound perfluoroacyl ligand. NMR analysis of Pt-
(dppe)(Me)(PPhi-Bu) (1) and Pt(dppe)(Me)(PPhIs) (2)
was inconclusive, but dynamic behavior was observed
for the complexes Pt(dppe)(COC3F7)(PPhAr) (11-15).
The fluxional behavior in the perfluoroacyl complexes
11-15 is consistent with the operation of two dynamic
processes: rotation around the Pt-phosphido bond and
inversion at the phosphido phosphorus. To explain the
observed NMR data, both processes must be fast at room
temperature in complexes 11-15. Therefore, we con-
clude that the calculated energy barriers (ca. 11-13
kcal/mol) for these processes provide an upper limit for
the barrier to pyramidal inversion in these complexes,
consistent with phosphido inversion barriers calculated
for other transition metal phosphido complexes. The
reduced inversion barriers in these Pt(II) complexes may
be explained by interaction of the phosphido lone pair
with the dyz and pz platinum orbitals, which could lower
the energy of the planar transition state relative to the
pyramidal ground state.
However, in the related d8 Rh(I) terminal phosphido
complex Rh(bupp2Ph4)(PCy2) (Chart 2, bupp2Ph4 ) (t-
Bu)P(CH2CH2CH2PPh2)2; Cy ) cyclo-C6H11), based on
the 31P NMR chemical shift of the phosphido ligand (δ
186) and the large J Rh-P (154 Hz) as compared to the
diphenylphosphido complex Rh(bupp2Ph4)(PPh2) (δ 26,
J Rh-P ) 92 Hz), Dahlenburg et al. suggested some
degree of Rh-P double-bond character.21 A Rh(pz)-P(p)
π-interaction was proposed on the basis of MO calcula-
tions for the square planar model complex Rh(PH3)3-
(PH2) with an sp2-hybridized phosphido ligand in the
RhL3 plane.
Exp er im en ta l Section
Gen er a l Deta ils. Unless otherwise noted, all reactions and
manipulations were performed in dry glassware under a
nitrogen atmosphere at 20 °C in a drybox or using standard
Schlenk techniques. Petroleum ether (bp 38-53 °C), ether,
THF, and toluene were dried and distilled before use from Na/
benzophenone. CH2Cl2 and acetonitrile were distilled from
CaH2.
Unless otherwise noted, all NMR spectra were recorded on
a Varian 300 MHz spectrometer. 1H and 13C NMR chemical
(22) Butts, M. D.; Scott, B. L.; Kubas, G. J . J . Am. Chem. Soc. 1996,
118, 11831-11843.
(23) Dahlenburg and co-workers (ref 21) include similar mixing with
a d-orbital of this symmetry, but use a slightly different coordinate
system.
(19) Mislow, K. Trans. N. Y. Acad. Sci. 1973, 35, 227-242.
(20) Mayer, J . M. Comments Inorg. Chem. 1988, 8, 125-135.
(21) Dahlenburg, L.; Hock, N.; Berke, H. Chem. Ber. 1988, 121,
2083-2093.

5138 Organometallics, Vol. 18, No. 24, 1999
Wicht et al.
shifts are reported relative to Me4Si and were determined by
reference to the residual 1H or 13C solvent peaks. 31P NMR
chemical shifts are reported relative to H3PO4 (85%) used as
an external reference. 19F NMR chemical shifts are reported
relative to CFCl3 used as an external reference. Unless
otherwise noted, peaks in NMR spectra are singlets. Coupling
constants are reported in hertz. Infrared spectra were recorded
mL) was added a solution of dppe (202 mg, 0.507 mmol) in
THF (5 mL). The reaction mixture immediately turned yellow.
The solvent was removed under vacuum, and the yellow
residue was washed twice with petroleum ether (5 mL por-
tions). The solid was dissolved in CH2Cl2 and filtered, and
ether was added. Cooling of this solution to -25 °C overnight
yielded 245 mg (70%) of product. Subsequent recrystallization
from CH2Cl2/ether gave crystals suitable for X-ray diffraction.
1H NMR (CD2Cl2): δ 7.87-7.80 (m, 4H, Ar), 7.73-7.67 (m, 4H,
Ar), 7.55-7.47 (m, 12H, Ar), 2.54-2.40 (m, 2H, dppe CH2),
using KBr pellets on
a Perkin-Elmer 1600 series FTIR
machine. Elemental analyses were provided by Schwarzkopf
Microanalytical Laboratory. Unless otherwise noted, reagents
were from commercial suppliers. The following compounds
were made by the literature procedures: Pt(dppe)(Me)(OMe),3
PHPhIs,5 Pt(PPh2Me)4,7 PHPho-anisyl,24 PH(Ph)(Mes).25
2.18-2.02 (m, 2H, dppe CH2). 13C{1H} NMR (CD2Cl2):
δ
134.0-133.4 (m, Ar), 132.5-132.4 (m, quat. Ar), 131.9-131.8
(m, quat. Ar), 129.6-128.9 (m, Ar), 127.5 (quat. Ar), 126.7
(quat. Ar), 31.8-31.1 (m, dppe CH2), 24.9-24.4 (m, dppe CH2).
The carbons of the COC3F7 ligand were not resolved. IR: 3059,
2916, 1662 (CdO), 1482, 1435, 1339, 1225, 1201, 1177, 1106,
P t(d p p e)(Me)(P P h Is) (2). To a stirred slurry of Pt(dppe)-
(Me)(OMe) (98 mg, 0.15 mmol) in THF (5 mL) was added
PHPhIs (57 mg, 0.18 mmol) in THF (2 mL). The reaction
mixture immediately became homogeneous, and the color
turned bright orange. The solvent was removed under vacuum,
and the yellow residue was washed twice with petroleum ether
(2 mL portions). The solid was dried and dissolved in a
minimum amount of THF. The THF solution was filtered, and
petroleum ether was added. Cooling of this solution to -25 °C
overnight gave 92 mg (65%) of a yellow solid. 1H NMR (toluene-
d8): δ 7.57-7.52 (m, 8H, Ar), 7.22-7.16 (m, 4H, Ar), 7.05-
6.99 (m, 12H, Ar), 6.74-6.68 (m, 3H, Ar), 4.79-4.68 (m, 2H,
876, 825, 747, 716, 706, 690, 535 cm-1. Anal. Calcd for C30H24
ClF7OP2Pt: C, 43.62; H, 2.93. Found: C, 43.51; H, 2.92.
-
[P t(d p p e)(COC3F 7)(NCMe)][BF 4] (5). To a slurry of Pt-
(dppe)(COC3F7)(Cl) (300 mg, 0.363 mmol) in THF (5 mL) and
CH3CN (3 mL) was added AgBF4 (71 mg, 0.36 mmol) in CH3-
CN (2 mL). Immediate formation of AgCl occurred as indicated
by a white precipitate. The reaction mixture was stirred
vigorously overnight. The cloudy gray reaction mixture was
filtered through a fine frit with Celite to give a yellow filtrate.
The solvent was removed under vacuum, and the pale yellow
residue was washed with petroleum ether (three 5 mL por-
tions) and dried to give 305 mg (91%) of crude product, which
was pure enough to use in subsequent reactions. A sample for
elemental analysis was recrystallized first from THF/petro-
leum ether at -25 °C and then from CH2Cl2/ether at -25 °C
to give a yellow powder. 1H NMR (CDCl3): δ 7.34-7.16 (broad
m, 20H, Ar), 2.43-2.31 (m, 2H, dppe CH2), 2.14-1.98 (m, 2H,
dppe CH2), 2.00 (3H, NCMe). IR: 3055, 2933, 2300 (CN), 1672
(CdO), 1483, 1439, 1411, 1339, 1205, 1111, 1061 (BF4), 822,
3
o-CHMe2), 2.85 (septet, J HH ) 7, 1H, p-CHMe2), 1.86-1.76
3
(m, 4H, dppe CH2), 1.27 (d, J HH ) 7, 6H, p-CHMe2), 1.21 (d,
2
3J HH ) 7, 12H, o-CHMe2), 0.89-0.83 (m, J Pt-H ) 67, 3H, Pt-
Me). 13C{1H} NMR (toluene-d8): δ 155.3-155.1 (m, quat. Ar),
147.7 (quat. Ar), 133.8-133.1 (m, Ar), 132.9 (quat. Ar), 132.4
(quat. Ar), 132.0 (quat. Ar), 131.5 (quat. Ar), 130.5 (Ar), 130.1
(Ar), 128.6 (Ar), 128.5 (Ar), 128.3 (Ar), 128.2 (Ar), 126.6-126.5
(m, Ar), 125.4 (quat. Ar), 125.1 (quat. Ar), 124.7 (quat. Ar),
123.3 (Ar), 121.3-121.2 (m, Ar), 34.6 (p-CHMe2), 33.9 (d, 3J PC
) 17, o-CHMe2), 32.6-31.9 (m, dppe CH2), 29.5-28.9 (m, dppe
750, 711, 688, 533, 489 cm-1. Anal. Calcd for C32H27NBF11
-
2
CH2), 25.7 (o-CHMe2), 24.4 (p-CHMe2), 2.7 (dd, J PC ) 83, 8,
Pt-Me, Pt satellites were not resolved). 31P{1H} NMR (toluene-
OP2Pt: C, 41.85; H, 2.96; N, 1.53. Found: C, 41.19; H, 2.96;
N, 1.33.
2
1
d8): δ 49.3 (d, J PP ) 174, J Pt-P ) 1969, P trans to PPhIs),
45.4 (1J Pt-P ) 1915, P trans to Me), -25.3 (d, 2J PP ) 174, 1J Pt-P
) 1118, PPhIs). IR: 3055, 2955, 2866, 1483, 1461, 1427, 1383,
[P t(d p p e)(COC3F 7)(P HP h Mes)][BF 4] (6). To a solution
of [Pt(dppe)(COC3F7)(NCMe)][BF4] (263 mg, 0.286 mmol) in
THF (5 mL) was added PHPhMes (73 mg, 0.32 mmol) in THF
(2 mL). The reaction mixture turned slightly darker yellow,
and the solvent was removed under vacuum. The yellow
residue was washed twice with petroleum ether (3 mL por-
tions) and dried to give 305 mg (96%) of crude product. Double
recrystallization from THF/petroleum ether at -25 °C gave
analytically pure light yellow powder. 1H NMR (CD2Cl2): δ
7.83-7.35 (broad m, 22H, Ar), 7.38-7.17 (m, 4H, Ar), 7.09 (dm,
1J PH ) 390, 1H, P-H), 6.82 (2H, Ar), 2.70-2.17 (m, 4H, dppe
CH2), 2.32 (6H, o-Me), 2.25 (3H, p-Me). IR: 3055, 2922, 2322
(w, P-H), 1672 (CdO), 1483, 1433, 1411, 1377, 1333, 1227,
1305, 1183, 1100, 1016, 877, 822, 744, 694, 644, 533, 488 cm-1
.
Anal. Calcd for C48H55P3Pt: C, 62.66; H, 6.04. Found: C, 62.10;
H, 5.72.
tr a n s-P t(P P h 2Me)2(COC3F 7)(Cl) (3). To a stirred suspen-
sion of Pt(PPh2Me)4 (656 mg, 0.656 mmol, recrystallized from
toluene/petroleum ether at -25 °C) in petroleum ether (80 mL)
was added dropwise a solution of C3F7COCl (300 µL, 2.01
mmol, distilled) in petroleum ether (5 mL) over a period of 15
min. The reaction mixture was allowed to stir at room
temperature for 2 h, during which time the bright yellow solid
gradually turned white. The solvent was removed via cannula
filter, and the white solid was washed twice with petroleum
ether (20 mL portions). Recrystallization from THF/petroleum
ether at -25 °C gave 418 mg (77%) of product as a white solid.
Further recrystallization from CH2Cl2/EtOH/ether gave crys-
tals suitable for X-ray diffraction. 1H NMR (CDCl3): δ 7.70
(broad, 8H, Ar), 7.44 (12H, Ar), 2.17 (apparent t, J ) 4, 3J Pt-H
1205, 1055 (BF4), 1000, 883, 850, 816, 744, 694, 533, 483 cm-1
.
Anal. Calcd for C45H41BF11OP3Pt: C, 48.89; H, 3.74. Found:
C, 49.06; H, 3.66.
[P t(d p p e)(COC3F 7)(P HP h o-a n isyl)][BF 4] (7). To a solu-
tion of [Pt(dppe)(COC3F7)(NCMe)][BF4] (266 mg, 0.290 mmol)
in THF (3 mL) was added PHPho-anisyl (69 mg, 0.32 mmol)
in THF (2 mL). The solvent was removed under vacuum. The
pale yellow residue was washed twice with petroleum ether
(3 mL portions) and dried to give 266 mg (84%) of crude
product. Recrystallization from THF/petroleum ether at -25
°C gave analytically pure off-white powder. 1H NMR (CD2-
Cl2): δ 7.75-7.51 (m, 14H, Ar), 7.44-7.35 (m, 7H, Ar), 7.31-
7.25 (m, 5H, Ar), 6.97-6.93 (m, 1H, Ar), 6.83-6.79 (m, 1H,
2
) 32, 6H, P-Me). 31P{1H} NMR (CDCl3): δ 6.5 (t, J PF ) 5,
1J Pt-P ) 2916). 19F NMR (CDCl3): δ -81.2 (t, J FF ) 9, CF3),
-111.5 to -111.6 (m, COCF2CF2), -127.6 to -127.7 (m,
COCF2CF2). IR: 3057, 2920, 1691, 1672 (CdO), 1485, 1436,
1334, 1209, 1183, 1105, 894, 734, 692, 659, 505, 487, 456 cm-1
.
Anal. Calcd for C30H26ClF7OP2Pt: C, 43.51; H, 3.17. Found:
C, 43.35; H, 3.17.
1
Ar), 6.65-6.58 (m, 1H, Ar), 6.39 (dm, J PH ) 410, 1H, P-H),
P t(d p p e)(COC3F 7)(Cl) (4). To a stirred solution of trans-
Pt(PPh2Me)2(COC3F7)(Cl) (350 mg, 0.423 mmol) in THF (10
4.03 (3H, OMe), 2.71-2.34 (m, 4H, dppe CH2). IR: 3051, 2354
(w, P-H), 1670 (CdO), 1474, 1436, 1338, 1278, 1218, 1060
(BF4), 907, 869, 820, 749, 695, 537, 488 cm-1. Anal. Calcd for
(24) Vedejs, E.; Donde, Y. J . Am. Chem. Soc. 1997, 119, 9293-9294.
(25) Wicht, D. K.; Kourkine, I. V.; Kovacik, I.; Glueck, D. S.;
Concolino, T. E.; Yap, G. P. A.; Incarvito, C. D.; Rheingold, A. L.
Organometallics, accepted for publication.
C
43H37BF11O2P3Pt: C, 47.23; H, 3.41. Found: C, 47.46; H, 3.25.
[P t(d p p e)(COC3F 7)(P HP h Is)][BF 4] (8). To a stirred solu-
tion of Pt(dppe)(COC3F7)(Cl) (177 mg, 0.214 mmol) and PHPhIs

Terminal Pt(II) Perfluoroacyl Phosphido Complexes
Organometallics, Vol. 18, No. 24, 1999 5139
(74 mg, 0.24 mmol) in CH2Cl2 (5 mL) was added AgBF4 (42
mg, 0.21 mmol) in CH3CN (2 mL). Immediate formation of
AgCl was observed, and the reaction mixture was stirred
vigorously for 30 min at room temperature. Filtration and
removal of solvent under vacuum gave a yellow residue. The
solid was washed twice with petroleum ether (3 mL portions)
and dissolved in THF. The solution was filtered, and petroleum
ether was added. Cooling of this solution to -25 °C overnight
0.21 mmol) in THF (2 mL). The solvent was removed under
vacuum. The yellow residue was washed twice with petroleum
ether (3 mL portions) and three times with ether (2 mL
portions) until the sticky solid became completely insoluble
in ether. Recrystallization from CH2Cl2/ether at -25 °C gave
162 mg (67%) of product. 1H NMR (CD2Cl2): δ 8.28-8.15
(broad m, 2H, Ar), 8.01-7.94 (m, 2H, Ar), 7.78-7.24 (m, 23H,
1
Ar), 7.22 (broad d, J PH ) 400, 1H, P-H), 2.81-2.41 (m, 4H,
1
gave 215 mg (84%) of product. H NMR (CDCl3): δ 7.96-7.92
dppe CH2). IR: 3055, 2322 (w, P-H), 1677 (CdO), 1627, 1583,
1483, 1433, 1338, 1283, 1200, 1061 (BF4), 916, 872, 855, 816,
744, 694, 533, 483 cm-1. Anal. Calcd for C45H32BF20OP3Pt: C,
42.64; H, 2.55. Found: C, 42.85; H, 2.50.
(m, 2H, Ar), 7.81-7.31 (m, 15H, Ar), 7.24-7.01 (m, 8H, Ar),
6.93-6.91 (m, 2H, Ar), 6.76 (dm, 1J PH ) 388, 1H, P-H), 2.97-
2.93 (m, 3H, dppe CH2 and p-CHMe2), 2.86-2.79 (m, 2H,
3
o-CHMe2), 2.37-2.30 (m, 2H, dppe CH2), 1.17 (d, J HH ) 7,
[P t(d p p e)(COC3F 7)(P HP h 2)][BF 4] (10). To a solution of
[Pt(dppe)(COC3F7)(NCMe)][BF4] (176 mg, 0.192 mmol) in THF
(3 mL) was added PHPh2 (37 µL, 0.21 mmol) via microliter
syringe. The solvent was removed under vacuum. The pale
yellow solid was washed twice with petroleum ether (2 mL
portions) and dried to yield 167 mg (82%) of crude product.
Double recrystallization from THF/petroleum ether at -25 °C
gave analytically pure light yellow powder. 1H NMR (CD2-
3
6H, p-CHMe2), 0.95 (d, J HH ) 7, 6H, o-CHMe2), 0.76 (broad,
6H, o-CHMe2). 13C{1H} NMR (CDCl3): δ 153.6-153.5 (m, quat.
Ar), 152.6-152.5 (m, quat. Ar), 134.6-134.4 (m, Ar), 133.9-
133.6 (m, Ar), 133.3-133.1 (m, Ar), 132.4-132.1 (m, Ar),
131.7-131.6 (m, Ar), 130.0-129.8 (m, Ar), 129.4-129.0 (m,
Ar), 127.0-124.3 (m, quat. Ar), 123.1-122.9 (m, Ar), 117.8-
117.7 (m, quat. Ar), 117.0-116.9 (m, quat. Ar), 34.2 (p-CHMe2),
33.6 (o-CHMe2), 33.5 (o-CHMe2), 27.8-26.8 (m, dppe CH2), 24.2
(p-CHMe2), 23.6 (o-CHMe2), 23.5 (o-CHMe2). The carbons of
the COC3F7 ligand were not resolved. IR: 3044, 2955, 2866,
2322 (w, P-H), 1672 (CdO), 1483, 1463, 1437, 1336, 1227,
1208, 1184, 1105, 1057 (BF4), 998, 879, 822, 746, 706, 692,
531, 484 cm-1. Anal. Calcd for C51H53BF11OP3Pt‚THF: C,
52.34; H, 4.88. Found: C, 52.49; H, 4.61. The presence of THF
1
Cl2): δ 7.72-7.26 (m, 30H, Ar), 6.33 (dm, J PH ) 395, 1H,
P-H), 2.70-2.33 (m, 4H, dppe CH2). IR: 3055, 2343 (w, P-H),
1672 (CdO), 1483, 1438, 1339, 1216, 1105, 1050 (BF4), 927,
905, 861, 822, 744, 700, 527, 477 cm-1. Anal. Calcd for C42H35
BF11OP3Pt: C, 47.43; H, 3.32. Found: C, 47.56; H, 3.19.
-
P t(d p p e)(COC3F 7)(P P h Mes) (11). To a solution of [Pt-
(dppe)(COC3F7)(PHPhMes)][BF4] (300 mg, 0.271 mmol) in THF
(5 mL) was added LiN(SiMe3)2 (55 mg, 0.33 mmol) in THF (3
mL). Alternatively, the phosphine complex could be generated
in situ by the addition of PHPhMes to [Pt(dppe)(COC3F7)-
(NCMe)][BF4] as described, identified spectroscopically, and
treated with base directly. The solvent was removed under
vacuum, and the yellow residue was washed with petroleum
ether (three 2 mL portions). The yellow solid was extracted
with ca. 50 mL of toluene and filtered through a fine frit with
Celite. The filtrate was concentrated to ca. 10 mL, and
petroleum ether was added. Cooling of this solution to -25 °C
gave 190 mg (69%) of product in two crops. 1H NMR (THF-
d8): δ 7.74 (broad, 3H, Ar), 7.63-7.57 (m, 4H, Ar), 7.46-7.16
(m, 13H, Ar), 6.89-6.88 (m, 2H, Ar), 6.89-6.63 (m, 3H, Ar),
6.45 (2H, Ar), 2.44 (6H, o-Me), 2.36-2.24 (m, 2H, dppe CH2),
2.18-2.05 (m, 2H, dppe CH2), 2.10 (3H, p-Me). IR: 3055, 2922,
1661 (CdO), 1572, 1483, 1433, 1333, 1227, 1205, 1105, 1027,
1000, 883, 850, 822, 744, 694, 527, 483 cm-1. Anal. Calcd for
1
in the analytical sample was confirmed by H NMR.
Syn th esis of P HP h Mes-F 9 a n d [P t(d p p e)(COC3F 7)-
(P HP h Mes-F 9)][BF 4] (9). LiMes-F9 was prepared according
to the reported procedure,26 and the secondary phosphine was
27
prepared by a modification of the procedure for PH2Mes-F9.
To a Schlenk flask containing 2,4,6-tris(trifluoromethyl)-
benzene (3.23 g, 11.4 mmol) in ether (10 mL) was transferred
n-BuLi (7.9 mL, 1.6 M in hexanes, 12.6 mmol) dropwise via
cannula. The addition was done over a period of 30 min at
room temperature, and the cloudy yellow solution was stirred
for an additional 30 min. A flask containing PPhCl2 (1.7 mL,
12.6 mmol) in ether (15 mL) was fitted with an addition funnel,
and the LiMes-F9 solution was transferred to the addition
funnel via cannula. The PPhCl2 solution was cooled to -78 °C
with a dry ice/acetone bath, and the lithium reagent was added
to this solution dropwise over a period of 45 min. The reaction
mixture was warmed to room temperature, and the solution
was filtered. The remaining LiCl was washed with ether (20
mL), and the filtrates were combined. The PClPhMes-F9
solution was transferred via cannula to a cold (dry ice/acetone)
gray slurry of LiAlH4 (836 mg, 22.9 mmol) in ether (20 mL).
The cold bath was removed, and the reaction mixture was
stirred at room temperature for 1 h. The reaction was carefully
quenched with degassed, distilled water, and then an ad-
ditional 40 mL of H2O was added. The ether layer was filtered
off, and the aqueous layer was washed twice with ether (20
mL portions). The combined ether layers were dried over
MgSO4. 31P NMR showed the desired product and phenylphos-
phine (caution, STENCH). The ether and phenylphosphine
were removed under vacuum to give a brownish oil. Degassed
2-propanol was added, and the yellow solution was cooled to
-25 °C to give 1.04 g (23%) of PH(Ph)Mes-F9 as a white solid
C
45H40F7OP3Pt: C, 53.10; H, 3.97. Found: C, 53.27; H, 4.03.
P t(d p p e)(COC3F 7)(P P h o-a n isyl) (12). To a solution of [Pt-
(dppe)(COC3F7)(PHPho-anisyl)][BF4] (225 mg, 0.206 mmol) in
THF (8 mL) was added LiN(SiMe3)2 (38 mg, 0.23 mmol) in THF
(5 mL). The reaction mixture immediately turned bright
yellow, and the solvent was removed under vacuum. The
yellow residue was extracted with toluene (20 mL) and filtered
through a fine frit with Celite. The filtrate was concentrated
to a volume of ∼3 mL, and petroleum ether was added. Cooling
of this solution overnight at -25 °C gave 100 mg (45%) of
bright yellow powder in two crops. Recrystallization from THF/
petroleum ether at -25 °C gave a sample for analysis. 1H NMR
(THF-d8): δ 7.68 (broad, 6H, Ar), 7.41-7.21 (broad m, 16H,
Ar), 6.86-6.71 (m, 5H, Ar), 6.55-6.53 (m, 1H, Ar), 6.37-6.33
(m, 1H, Ar), 3.85 (3H, OMe), 2.44-2.14 (m, 4H, dppe CH2).
IR: 3052, 1648 (CdO), 1577, 1463, 1436, 1338, 1267, 1229,
1202, 1104, 1027, 880, 815, 744, 695, 531, 488 cm-1. Anal.
Calcd for C43H36F7O2P3Pt: C, 51.35; H, 3.62. Found: C, 51.20;
H, 3.90.
P t(d p p e)(COC3F 7)(P P h Is) (13). To a stirred suspension
of [Pt(dppe)(COC3F7)(PHPhIs)][BF4] (358 mg, 0.301 mmol) in
THF (10 mL) was added LiN(SiMe3)2 (61 mg, 0.36 mmol) in
THF (5 mL). The reaction mixture immediately became bright
orange and was allowed to stir at room temperature for 15
min. The solvent was removed under vacuum, and the yellow-
orange residue was washed three times with petroleum ether
(5 mL portions). The solid was extracted with 20 mL of toluene
1
in two crops. H NMR (C6D6): δ 7.84 (2H, Ar), 7.17-7.12 (m,
1
2H, Ar), 7.00-6.69 (m, 3H, Ar), 5.73 (d septet, J PH ) 234,
4
5J HF ) 4, P-H). 31P{1H} NMR (C6D6): δ -59.0 (septet, J PF
)
27 Hz). 31P NMR (C6D6): δ -59 (dm, J PH ) 234). 19F NMR
(C6D6): δ -58.0 (dd, J PF ) 27, J HF ) 4, o-CF3), -63.7 (p-
CF3).
1
4
5
To a solution of [Pt(dppe)(COC3F7)(NCMe)][BF4] (176 mg,
0.192 mmol) in THF (3 mL) was added PHPhMes-F9 (82 mg,
(26) Carr, G. E.; Chambers, R. D.; Holmes, J . F.; Parker, D. G. J .
Organomet. Chem. 1987, 325, 13-23.
(27) Schollz, M.; Roesky, H. W.; Stalke, D.; Keller, K.; Edelmann,
F. T. J . Organomet. Chem. 1989, 366, 73-85.

5140 Organometallics, Vol. 18, No. 24, 1999
Wicht et al.
and filtered through a fine frit with Celite. The bright orange
filtrate was concentrated to 5 mL, and petroleum ether was
added. Cooling of this solution to -25 °C gave 237 mg (71%)
of bright yellow product. 1H NMR (toluene-d8): δ 7.67-7.61
(m, 4H, Ar), 7.53-7.47 (m, 4H, Ar), 7.36-7.32 (m, 2H, Ar),
7.14-6.91 (m, 14H, Ar), 6.73-6.71 (m, 3H, Ar), 4.72-4.67 (m,
Va r ia ble-Tem p er a tu r e NMR Da ta . The reported tem-
peratures were calibrated from the chemical shift difference
1
of the signals in the H NMR spectrum of a standard sample
of methanol (temperatures < 20 °C) or ethylene glycol (tem-
peratures > 20 °C). The uncertainty in the ∆Gq(Tc) values was
estimated on the basis of the assumption that there is an error
of (10 °C in the determination of the coalescence temperature.
Cr ysta llogr a p h ic Str u ctu r a l Deter m in a tion . Crystal,
data collection, and refinement parameters are given in Table
3. Suitable crystals for single-crystal X-ray diffraction were
selected and mounted either in a nitrogen-flushed, thin-walled
capillary or on the tip of a fine glass fiber with epoxy cement.
The data were collected on a Siemens P4 diffractometer
equipped with a SMART/CCD detector.
3
2H, o-CHMe2), 2.79 (septet, J HH ) 7, 1H, p-CHMe2), 1.87-
1.57 (m, 4H, dppe CH2), 1.24 (d, 3J HH ) 7, 6H, p-CHMe2), 1.19
3
(broad d, J HH ) 6, 12H, o-CHMe2). 13C{1H} NMR (toluene-
d8): δ 154.9-154.7 (m, quat. Ar), 148.3 (quat. Ar), 146.6-146.2
(m, quat. Ar), 136.6 (quat. Ar), 136.3 (quat. Ar), 135.2 (Ar),
134.9 (Ar), 134.0-133.7 (m, Ar), 131.5 (quat. Ar), 131.2 (Ar),
130.9 (quat. Ar), 130.5 (Ar), 128.8 (Ar), 128.7 (Ar), 128.3 (Ar),
128.2 (Ar), 126.6-126.5 (m, Ar), 125.4 (quat. Ar), 125.1 (quat.
Ar), 124.7 (Ar), 121.6-121.5 (m, Ar), 34.5 (p-CHMe2), 34.1 (d,
3J PC ) 17, o-CHMe2), 29.5-28.8 (m, dppe CH2), 25.8 (o-CHMe2),
24.2 (p-CHMe2). IR: 3054, 2957, 2865, 1651 (CdO), 1579, 1482,
1462, 1436, 1414, 1335, 1225, 1204, 1104, 1026, 879, 823, 742,
694, 650, 594, 529, 484 cm-1. Anal. Calcd for C51H52F7OP3Pt:
C, 55.58; H, 4.77. Found: C, 55.66; H, 4.97.
P t(d p p e)(COC3F 7)(P P h Mes-F 9) (14). To a solution of [Pt-
(dppe)(COC3F7)(PHPhMes-F9)][BF4] (224 mg, 0.177 mmol) in
THF (5 mL) was added LiN(SiMe3)2 (30 mg, 0.18 mmol) in THF
(3 mL). Alternatively, the phosphine complex could be gener-
ated in situ by the addition of PHPhMes-F9 to [Pt(dppe)-
(COC3F7)(NCMe)][BF4] as described, identified spectroscopi-
cally, and treated with base directly. The solvent was removed
under vacuum to give a dark orange residue. The residue was
extracted with toluene (∼10 mL) and filtered through a fine
frit with Celite. The solvent was removed under vacuum, and
the orange residue was dissolved in ether. The ether solution
was filtered and concentrated under vacuum to a volume of
∼3 mL. Petroleum ether was added, and cooling of this solution
to -25 °C overnight gave 148 mg (71%) of orange-red product.
1H NMR (toluene-d8): δ 8.05 (2H, Ar), 7.51 (broad, 6H, Ar),
7.41-7.36 (m, 3H, Ar), 7.05 (broad, 6H, Ar), 6.90 (broad, 6H,
Ar), 6.78-6.65 (m, 4H, Ar), 1.82-1.61 (m, 4H, dppe CH2). IR:
3055, 1661 (CdO), 1572, 1483, 1433, 1366, 1333, 1277, 1189,
1133, 1072, 1028, 905, 883, 861, 822, 744, 700, 533, 483, 433
cm-1. Anal. Calcd for C45H31F16OP3Pt: C, 45.81; H, 2.65.
Found: C, 45.40; H, 2.65.
P t(d p p e)(COC3F 7)(P P h 2) (15). To a solution of [Pt(dppe)-
(COC3F7)(PHPh2)][BF4] (142 mg, 0.134 mmol) in THF (3 mL)
was added LiN(SiMe3)2 (25 mg, 0.15 mmol) in THF (2 mL).
The reaction mixture immediately became bright yellow, and
the solvent was removed under vacuum. The yellow residue
was washed three times with petroleum ether (1 mL portions)
and dried. The yellow solid was extracted with toluene (20 mL)
and filtered through a fine frit with Celite. The filtrate was
concentrated to a volume of ∼2 mL, and petroleum ether was
added. Cooling of this solution overnight at -25 °C gave 79
mg (61%) of product in two crops. 1H NMR (THF-d8): δ 7.62-
7.23 (broad m, 9H, Ar), 7.10-6.71 (broad m, 21H, Ar), 1.91-
1.58 (m, 4H, dppe CH2). IR: 3055, 1655 (CdO), 1483, 1433,
1333, 1228, 1205, 1111, 1027, 994, 877, 822, 744, 694, 527,
483 cm-1. Anal. Calcd for C42H34F7OP3Pt: C, 51.70; H, 3.52.
Found: C, 51.77; H, 3.81.
The systematic absences in the diffraction data are uniquely
consistent with the reported space group for 4, and no evidence
of symmetry higher than triclinic was observed in the diffrac-
tion data of 3. E-statistics suggested the centrosymmetric
space group option, P1h, which yielded chemically reasonable
and computationally stable results of refinement. The struc-
tures were solved by direct methods, completed by subsequent
difference Fourier syntheses, and refined by full-matrix least-
squares procedures. An empirical absorption correction was
applied to the data of 3, based on a Fourier series in the polar
angles of the incident and diffracted beam paths, and was used
to model an absorption surface for the difference between the
observed and calculated structure factors.28 No other absorp-
tion corrections were required because there was less than 10%
variation in the integrated ψ-scan intensities. One-half of a
molecule of dichloromethane, disordered over an inversion
center, was located in the asymmetric unit of 3. All other non-
hydrogen atoms were refined with anisotropic displacement
parameters. All other hydrogen atoms were treated as ideal-
ized contributions.
All software and sources of the scattering factors are
contained in the SHELXTL (5.03 and 5.10) program libraries
(G. Sheldrick, Siemens XRD, Madison, WI).
Ack n ow led gm en t. We thank the NSF Career Pro-
gram, the Petroleum Research Fund, administered by
the American Chemical Society, the Exxon Education
Foundation, DuPont, and Union Carbide (Innovation
Recognition Program) for partial support. We are grate-
ful to Profs. R. P. Hughes, M. Brookhart, and M. Gagne
for helpful discussions. The University of Delaware
thanks the NSF (CHE-9628768) for their support of the
purchase of the CCD-based diffractometer.
Su p p or tin g In for m a tion Ava ila ble: Details of the crys-
tal structure determinations. This material is available free
of charge via the Internet at http://pubs.acs.org.
OM9903691
(28) Walker, N.; Stuart, D. Acta Crystallogr. 1983, A39, 158-166.