Synthesis, molecular structures, and chemistry of some new palladium(II) and platinum(II) complexes with pentafluorophenyl ligands

Article abstract of DOI:10.1039/b406602b

A series of palladium(II) and platinum(II) complexes possessing pentafluorophenyl ligands of the general formula [M(L-L)(C₆F ₅)Cl] (M = Pd 3; L-L = tmeda (N,N,N′,N′,- tetramethylethylenediamine) a; 1,2-bis(2,6-dimethylphenylimino)ethane) b; dmpe (1,2-bis(dimethylphosphino)ethane) c; dcpe (1,2-bis(dicyclohexylphosphino) ethane) d; Pt 4; L-L = tmeda a; 1,2-bis[3,5-bis(trifluoromethyl)phenylimino]-1, 2-dimethylethane b; dmpe c; dcpe d) were readily synthesized from the dimer [M(C₆F₅)(tht)(μCl)₂] (M = Pd 1b, Pt 2b; tht = tetrahydrothiophene) and the corresponding bidentate ligand. In the case of palladium, the corresponding iodo analogues (6a-c) were readily synthesized in a one-pot reaction from [Pd₂(dba)₃], iodopentafluorobenzene, and the appropriate ligand. The platinum complexes 4c-d were then converted to the water complexes [Pt(L-L)(C₆F ₅)(OH₂)]OTf (L-L = dmpe 7a; dcpe 7b) via reaction with AgOTf in the presence of water. Attempts to convert the palladium complexes 3c-d to the corresponding water complexes resulted in the disproportionation of the intermediate water complex to form [Pd(L-L)(C₆F₅) ₂] (L-L = dmpe 8) or [Pd(L-L)₂][OTf]₂ (L-L = dcpe 9). Upon standing in solution for prolonged periods, complex 7a undergoes an identical disproportionation reaction to the Pd analogues to form [Pt(L-L)(C₆F₅)₂] (L-L = dmpe 10). Complexes 4c and 4d were converted to the corresponding hydrides (11b-c, respectively) using two different hydride sources: 11a was formed by the reaction of 4c with NaBH₄ in refluxing THF, while 11b was synthesized in near quantitative yield using [Cp₂ZrH₂] in refluxing THF. Attempts to synthesize η²-tetrafluorobenzyne complexes [Pt(L-L)(C₆F₄)] (L-L = dmpe, dcpe) from reaction of 11a-b with butyllithium were unsuccessful. The molecular structures of 3a, 4a, 4c, 4d, 6b, 7a, 8, and lib have been determined by X-ray crystallographic studies, and are discussed.

Full text of DOI:10.1039/b406602b

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F U L L P A P E R
Synthesis, molecular structures, and chemistry of some new
palladium(II) and platinum(II) complexes with pentafluorophenyl
ligands
Russell P. Hughes,*a Antony J. Ward,a James A. Golen,b Christopher D. Incarvito,c
Arnold L. Rheingoldd and Lev N. Zakharovd
a
Department of Chemistry, Dartmouth College, 6128 Burke Laboratory, Hanover,
New Hampshire 03755 USA. E-mail: rph@dartmouth.edu; Tel: +603-646-2763
Department of Chemistry, University of Massachusetts Dartmouth, North Dartmouth,
b
MA 02747 USA
c
Department of Chemistry, Yale University, New Haven, 06520-8107 USA
Department of Chemistry and Biochemistry, University of California, San Diego,
d
9500 Gilman Drive, La Jolla, CA 92093-0358 USA
Received 4th May 2004, Accepted 16th June 2004
First published as an Advance Article on the web 23rd July 2004
A series of palladium(II) and platinum(II) complexes possessing pentafluorophenyl ligands of the general formula
[M(L–L)(C6F5)Cl] (M = Pd 3; L–L = tmeda (N,N,N′,N′,-tetramethylethylenediamine) a; 1,2-bis(2,6-dimethylphenyl-
imino)ethane) b; dmpe (1,2-bis(dimethylphosphino)ethane) c; dcpe (1,2-bis(dicyclohexylphosphino)ethane) d; Pt 4;
L–L = tmeda a; 1,2-bis[3,5-bis(trifluoromethyl)phenylimino]-1,2-dimethylethane b; dmpe c; dcpe d) were readily
synthesized from the dimer [M(C6F5)(tht)(-Cl)2] (M = Pd 1b, Pt 2b; tht = tetrahydrothiophene) and the corresponding
bidentate ligand. In the case of palladium, the corresponding iodo analogues (6a–c) were readily synthesized in a one-pot
reaction from [Pd2(dba)3], iodopentafluorobenzene, and the appropriate ligand. The platinum complexes 4c–d were then
converted to the water complexes [Pt(L–L)(C6F5)(OH2)]OTf (L–L = dmpe 7a; dcpe 7b) via reaction with AgOTf in the
presence of water. Attempts to convert the palladium complexes 3c–d to the corresponding water complexes resulted in
the disproportionation of the intermediate water complex to form [Pd(L–L)(C6F5)2] (L–L = dmpe 8) or [Pd(L–L)2][OTf]2
(L–L = dcpe 9). Upon standing in solution for prolonged periods, complex 7a undergoes an identical disproportionation
reaction to the Pd analogues to form [Pt(L–L)(C6F5)2] (L–L = dmpe 10). Complexes 4c and 4d were converted to the
corresponding hydrides (11b–c, respectively) using two different hydride sources: 11a was formed by the reaction of 4c
with NaBH4 in refluxing THF, while 11b was synthesized in near quantitative yield using [Cp2ZrH2] in refluxing THF.
Attempts to synthesize 2-tetrafluorobenzyne complexes [Pt(L–L)(C6F4)] (L–L = dmpe, dcpe) from reaction of 11a–b with
butyllithium were unsuccessful. The molecular structures of 3a, 4a, 4c, 4d, 6b, 7a, 8, and 11b have been determined by
X-ray crystallographic studies, and are discussed.
2,6-Me2Ar 3b, dmpe 3c, dcpe 3d: M = Pt; L–L = tmeda 4a,
Introduction
3,5-(CF3)2ArNC(CH3)C(CH3)N-3,5-(CF3)2Ar 4b, dmpe 4c,
Recent work within our research group has shown that treatment
dcpe 4d) as shown in Scheme 1. In the case of the Pd complexes,
of [Cp*Ir(PMe3)(C6F5)H] with excess n-butyllithium resulted in
stirring the dimer in THF in the presence of the ligand at room tem-
the formation of the first transition metal-2-tetrafluorobenzyne
perature is sufficient to form the desired mononuclear complexes,
complex [Cp*Ir(PMe3)(C6F4)].1 This reaction scheme, involving
but formation of the analogous platinum complexes required heat-
apparent deprotonation of the hydride and elimination of an ortho-
ing a chloroform (or toluene) solution of the dimer and the ligand.
fluorine, proved to be a general route to partially fluorinated and
non-fluorinated benzyne complexes of iridium and rhodium.2,3 In
seeking to expand the applicability of this reaction to the prepara-
tion of fluorinated benzyne complexes of other metals, we sought
routes to other hydrido(pentafluorophenyl)metal complexes. Since
benzyne complexes of palladium and platinum are well-known,4–7
these metals seemed like good choices. In addition, a large body
of work concerning pentahalophenyl derivatives of palladium and
platinum8 has resulted in characterization of several precursors
for the synthesis of a large variety of complexes possessing these
aryl ligands.9–15 In this paper we describe the syntheses of several
platinum and palladium complexes containing pentafluorophenyl
ligands as potential, albeit unsuccessful, precursors for fluorinated
benzyne complexes.
Scheme 1
Results and discussion
Halo complexes
A second synthetic route is also available to form iodo analogues
The dimeric complexes [M(C6F5)2(tht)2(-Cl)2] (tht = tetrahydro-
thiophene; M = Pd 1, Pt 2) undergo ready displacement of tht by
the appropriate chelating ligand to afford complexes [M(L–L)-
(C6F5)Cl] (M = Pd; L–L = tmeda 3a, 2,6-Me2ArNCHCHN-
of the Pd complexes. This is a ‘one-pot’synthesis that involves heat-
ing a benzene solution of [Pd(dba)2] (dba = dibenzylideneacetone)
5 in the presence of the appropriate ligand and C6F5I as shown in
Scheme 2.
2 7 2 0
D a l t o n T r a n s . , 2 0 0 4 , 2 7 2 0 – 2 7 2 7
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 4

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Scheme 4
Scheme 2
obtained in 98% yield when a THF solution of 4d was stirred with
1 equivalent of [Cp2ZrH2] at room temperature. Despite numerous
attempts using different hydride sources (such as NaBH4, LiBHEt3,
and [Cp2ZrH2]), no Pd hydride complexes could be synthesized.
The hydrido compounds were readily identified using NMR, with
the hydride resonance for 11a appearing as a doublet of doublet of
multiplets at  −1.48 ppm, with 2JP(cis)H = 17 Hz, 2JP(trans)H = 200 Hz,
The yields after recrystallization are generally good except when
phosphine ligands are used: in these cases the C6F5I is apparently
sufficiently electrophilic to react with the free phosphine, so yields
of the desired complexes are low and the product is difficult to
purify. Low yields were also observed when the [Pd(dmpe)(dba)]
complex was formed in situ prior to addition of the C6F5I.
Water complexes of Pt were readily synthesized in moderate
yields by slow addition of the halo complex to a suspension of
AgOTf in chloroform at room temperature as shown in Scheme 3.
1
and JPtH = 1080 Hz. Similarly, the hydride resonance for 11b ap-
pears as a doublet of doublet of multiplets at  −0.30 ppm, with
2
2JP(cis)H = 4.5 Hz, JP(trans)H = 165 Hz and a Pt–H coupling constant
of 1036 Hz. The multiplet component of the resonances arises from
the coupling of the hydride with the AA′MM′X spin system of the
C6F5 ligand.
As stated in the Introduction, the ultimate aim of this work was to
synthesize tetrafluorobenzyne complexes utilizing the dehydrofluo-
rination protocol that was recently developed within this research
group.1–3 Unfortunately this methodology proved unsuccessful
using the only two hydrides 11a,b. Treatment of 11a with excess
n-butyllithium in hexane at room temperature for 24 h resulted in
decomposition with no resonances attributable to the desired 2-
tetrafluorobenzyne complex present. In the case of 11b, the dcpe
ligand appears to be too large to allow the abstraction of the hydride
by either n-butyllithium or t-butyllithium, and starting material was
obtained after the reaction was worked-up.
Scheme 3
The complexes were obtained as white powders upon precipita-
tion. Attempts to make the analogous palladium water complexes
from 3c or 3d proved unsuccessful due to apparent disproportion-
ation reactions, which occurred before any water complex could
be isolated. When dmpe was the chelate ligand the only isolable
product from reaction of 3c was [Pd(dmpe)(C6F5)2] (8), while the
corresponding reaction of 3d afforded only [Pd(dcpe)2][OTf]2 (9).
The fate of the missing pentafluorophenyl groups or excess palla-
dium has not been determined. In the case of platinum complex 7a
the analogous disproportionation reaction occurs at a significantly
slower rate, taking 3 weeks of stirring at room temperature in CHCl3
to form [Pt(dmpe)(C6F5)2] 10. In the case of the dcpe complex 7b no
reaction was observed after stirring the complex at room tempera-
ture for 3 weeks. Authentic samples of complexes 8 and 10 were
synthesized independently in order to confirm their formation in the
disproportionation reactions. Addition of dmpe to a THF solution
of [M(C6F5)2(tht)2] (M = Pd 1; Pt 2) afforded the desired complexes
in high yields.
Despite this disappointing outcome to our synthetic aspirations,
a number of new pentafluorophenyl complexes resulted from these
studies. Several have been characterized by X-ray crystallography,
and show some interesting features, described below.
Structural studies
The structures of complexes 3a (Fig. 1), 4a (Fig. 2), 4c (Fig. 3), 4d
(Fig. 4) and 6b (Fig. 5) were determined by X-ray crystallography.
In each case, X-ray diffraction quality crystals were grown by the
slow infusion of hexanes into a CH2Cl2 solution of the complex. In
two cases the crystals included a half (4c) or whole (4d) molecule
of CH2Cl2 in the lattice, not included in the ORTEP diagrams. De-
tails of all crystal structure determinations are presented in Table 1.
Selected bond lengths and angles for the coordination sphere of the
metal in each compound are presented in Table 2. To make for easy
comparison a common numbering system is used with atom X(1)
(X = Cl, I, H, OH2) always trans to L(2) (L = N, P), and atom C(1)
(the coordinated carbon of the C6F5 moiety) always trans to L(1).
In the case of the palladium complexes 3a and 6b, the observed
Pd–C(1), Pd–N(1), and Pd–N(2) bond lengths are close to identical.
Such comparisons for the Pt complexes 4a, 4c, and 4d cannot be
drawn due to the different coordinating atoms of the ligands. The
trans-influence is clearly illustrated when comparing the M–L(1)
and M–L(2) bond lengths: in all cases, the M–L(2) bond length
is longer than the M–L(1) bond length, indicating that a stronger
trans-influence is exerted by the C6F5 group than by the halide. The
crystal structures of all complexes show that the pentafluorophenyl
moiety subtends an angle of approximately 85° to the plane formed
by the metal, bidentate ligand and the halide.
Hydride complexes
The syntheses of the target hydride complexes was successful
in only two cases to give platinum complexes 11a and 11b, and
required different hydride sources for the different precursors.
Attempts to make the complex [Pt(tmeda)(C6F5)H] from 4a using
hydride sources such as NaBH4, LiEt3BH, and [Cp2ZrH2] resulted
in complete decomposition of the starting material, while heating 4a
in the presence of NaBH3CN in THF resulted in no observable reac-
tion. Likewise, the synthesis of 11a from the water complex 7a and
Proton Sponge® was also attempted, but no reaction was observed,
in contrast to the high yield synthesis of hydrido-iridium complexes
using this approach.16 A successful synthesis of [Pt(dmpe)(C6F5)H]
11a was only achieved in modest yield (59%) using NaBH4; when
[Cp2ZrH2] was used, multiple products were obtained that could not
be separated. In contrast, the hydride [Pt(dcpe)(C6F5)H] 11b was
X-ray diffraction quality crystals of 7a were grown from the slow
infusion of hexanes into a solution of CH2Cl2 containing the com-
plex. The structure contains four independent molecules in the
asymmetric unit; the ORTEP diagram of one is shown in Fig. 6. The
X-ray structure shows the complex to be planar, with the C6F5 group
subtending an angle of approximately 85° with the plane formed by
the Pt, the 2 phosphorus atoms, and the O. The bond lengths for the
coordination sphere of the metal show that the C6F5 groups exerts
a stronger trans-influence than the coordinated water molecule
D a l t o n T r a n s . , 2 0 0 4 , 2 7 2 0 – 2 7 2 7
2 7 2 1

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2 7 2 2
D a l t o n T r a n s . , 2 0 0 4 , 2 7 2 0 – 2 7 2 7

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Fig. 5 ORTEP diagram of the non-hydrogen atoms of 6b, showing the
atom labelling scheme. Thermal ellipsoids shown at 30% probability.
Fig. 1 ORTEP diagram of the non-hydrogen atoms of 3a, showing the
atom labelling scheme. Thermal ellipsoids shown at 30% probability.
Fig. 2 ORTEP diagram of the non-hydrogen atoms of 4a, showing the
atom labelling scheme. Thermal ellipsoids shown at 30% probability. Only
one position of the disordered C(7), C(8) atoms is shown.
Fig. 6 ORTEP diagram of the non-hydrogen atoms of 7a, showing the
atom labelling scheme. Thermal ellipsoids shown at 30% probability.
resulting in a longer Pt–P(2) bond length of 2.280 Å (compared to
2.187 Å for the Pt–P(1) bond). The angles show deviations from
the ideal, however, this presumably results from the bite angle of
the bidentate phosphine. Although the H atoms on the coordinated
water molecules were not found from the F-map the found inter-
molecular OO distances (2.61–2.76 Å) indicate the existence
of strong O–HO H-bonds between the water molecule and the
O3SCF3 groups for all four independent molecules.
An X-ray diffraction quality crystal of [Pd(dmpe)(C6F5)2 8 was
also obtained. The ORTEP diagram of 8 is shown in Fig. 7. In the
crystal structure the molecule has C2 symmetry; the Pd(1) atom and
the middle of the C(7)–C(7a) bond are on a 2-fold axis. The complex
is almost planar about the Pd center; the dihedral angle between the
C(1)Pd(1)C(1a) and P(1)Pd(1)P(1a) planes is 1.46(9)°.
Fig. 3 ORTEP diagram of the non-hydrogen atoms of 4c, showing the
atom labelling scheme. Thermal ellipsoids shown at 30% probability.
Fig. 7 ORTEPdiagram of the non-hydrogen atoms of 8, showing the atom
Fig. 4 ORTEP diagram of the non-hydrogen atoms of 4d, showing the
labelling scheme. Thermal ellipsoids shown at 30% probability.
atom labelling scheme. Thermal ellipsoids shown at 30% probability.
D a l t o n T r a n s . , 2 0 0 4 , 2 7 2 0 – 2 7 2 7
2 7 2 3

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X-ray diffraction quality crystals of 11b were obtained by the
slow evaporation of a benzene solution of the complex. The num-
bering system utilized is consistent with that used previously. An
ORTEP diagram of 11b is shown in Fig. 8. The metal complex is
planar about the Pt center with the C6F5 moiety subtending an angle
of approximately 85° with the plane defined by the Pt, the 2 phos-
phorus atoms and the hydride. The hydride ligand exerts a larger
trans-influence than the C6F5 ligand resulting in a significantly
longer Pt–P(1) bond than the Pt–P(2) bond (2.3006 Å compared to
2.2383 Å). Deviations from ideal angles are observed, however, this
is the result of the bite angle of the phosphine ligand.
for C12H16ClF5N2Pd: %C, 33.90; %H, 3.80. Found: %C, 34.05;
%H, 3.65.
[1,2-bis(2,6-dimethylphenylimino)ethane](chloro)pentafluoro-
phenylpalladium(II) 3b. To a solution of 1b (100 mg, 0.13 mmol)
in THF (10 mL) was added 1,2-bis(2,6-dimethylphenylimino)eth
ane (66 mg, 0.25 mmol) and the reaction mixture was stirred at
room temperature overnight. The solvent was reduced in volume
to 5 mL in vacuo and hexane was added. The solution was cooled
to −30 °C. Filtration afforded the product as a bright orange mi-
crocrystalline powder (80 mg, 56%). 1H NMR (CDCl3):  8.19 (s,
2H, NCH), 7.20 (m, 2H, m-ArH), 7.05 (m, 2H, 2 × p-ArH), 6.95
(m, 2H, m-ArH), 2.46 (s, 6H, 2 × ArCH3), 2.31 (s, 6H, 2 × ArCH3)
ppm. 19F NMR (CDCl3):  −119.28 (m, 2F, o-ArF), −160.67 (t, 1F,
3JFF = 19 Hz, p-ArF), −163.85 (m, 2F, m-ArF) ppm. Anal. Calcd.
for C24H20ClF5N2Pd: %C, 50.28; %H, 3.52. Found: %C, 50.49;
%H, 3.48.
[1,2-bis(dimethylphosphino)ethane](chloro)(pentafluoro-
phenyl)palladium(II) 3c. To a solution of 1b (150 mg, 0.19 mmol)
in THF (10 mL) at 0 °C was added a solution of dmpe (63 L,
0.38 mmol) in THF (5 mL). The reaction mixture was stirred over-
night at room temperature. The solvent was removed in vacuo. The
residue was washed with hexane. Filtration afforded the product
as a white powder (163 mg, 94%). 1H NMR (CDCl3):  2.14–1.88
2
(m, 4H, PCH2), 1.73 (d, 6H, JPH = 11 Hz, PCH3), 1.55 (d, 6H,
2JPH = 12 Hz, PCH3) ppm. 19F NMR (CDCl3):  −117.23 (m, 2F, o-
ArF), −160.06 (t, 1F, 3JFF = 20 Hz, p-ArF), −162.53 (m, 2F, m-ArF)
ppm. 31P{1H} NMR (CDCl3):  47.1 (m, P trans to Cl), 42.7 (m, P
trans to C6F5) ppm. Anal. Calcd. for C12H16ClF5Pd.0.5CH2Cl2: %C,
29.93; %H, 3.42. Found: %C, 30.43; %H, 3.57.
Fig. 8 ORTEP diagram of the non-hydrogen atoms (with the exception of
H1) of 11b, showing the atom labelling scheme. Thermal ellipsoids shown
at 30% probability.
[1,2-bis(dicyclohexylphosphino)ethane](chloro)(pentafluoro-
phenyl)palladium(II) 3d. To a solution of 1b (100 mg, 0.13 mmol)
in THF (10 mL) was added a solution of dcpe (109 mg, 0.26 mmol)
in THF (10 mL) and the reaction mixture was stirred at room tem-
perature overnight. The solvent was removed in vacuo and the
residue extracted with hexanes. Filtration afforded the product as
a white powder (180 mg, 98%). 1H NMR (CDCl3):  2.32 (m, 2H,
PCH2), 2.10–1.62 (m, 22H, PC6H11), 1.60–1.12 (m, 22H, PC6H11),
0.87 (m, 2H, PCH2) ppm. 19F NMR (CDCl3):  −115.82 (m, 2F, o-
ArF), −161.06 (t, 1F, 3JFF = 20 Hz, p-ArF), −162.95 (m, 2F, m-ArF)
ppm. 31P{1H} NMR (CDCl3):  83.74 (s, P trans to Cl), 76.52 (m,
P trans to C6F5) ppm. Anal. calcd. for C32H48ClF5P2Pd.0.75CH2Cl2:
%C, 49.45; %H, 6.28. Found: %C, 49.39; %H, 6.34.
Experimental
General considerations
Unless otherwise noted, all reactions were performed in oven-dried
glassware, using standard Schlenk techniques, under an atmosphere
of nitrogen, which had been deoxygenated over BASF catalyst and
dried usingAquasorb®. Solvents were deoxygenated and dried over
activated alumina using an apparatus modified from that described
in literature.17 1H (300 MHz), 19F (282 MHz) and 31P (121.4 MHz)
NMR spectra were recorded on a Varian Unity-300 spectrometer at
25 °C. Chemical shifts are reported as ppm downfield of TMS (1H,
referenced to solvent) or internal CFCl3 (19F). Coupling constants
are reported in Hertz. Microanalyses were performed by Schwartz-
kopf Microanalytical Laboratory (Woodside, NY).
Bromo- and iodopentafluorobenzene were purchased from
Aldrich and used without further purification. The ligands 1,2-
bis(dimethylphosphino)ethane (dmpe) and 1,2-bis(dicyclohexyl-
phosphino)ethane (dcpe) were purchased from Strem and used
withoutfurtherpurification. N,N,N′,N′-Tetramethylethylenediamine
(tmeda) was purchased from Aldrich and was distilled from KOH
before use. The complexes [M(C6F5)2(tht)2] (M = Pd 1a, Pt 2a),12
[M2(C6F5)2(tht)2(-Cl)2] (M = Pd 1b, Pt 2b),12,13 [Pd(dba)2] 5,18 and
[Cp2ZrH2]19 werepreparedaccordingtopublishedliteraturemethods.
The diimine ligands 1,2-bis(2,6-dimethylphenylimino)ethane20 and
1,2-bis[3,5-bis(trifluoromethyl)phenylimino]-1,2-dimethylethane21
were synthesized using published literature methods.
[1,2-bis(dimethylamino)ethane](chloro)(pentafluorophenyl)-
platinum(II) 4a. To a solution of 2b (100 mg, 0.10 mmol) in
chloroform (10 mL) was added tmeda (47 L, 0.31 mmol). The
reaction mixture was heated at reflux for 1 h, then stirred over-
night at room temperature. The solvent was reduced in volume
in vacuo to 5 mL and hexane was added. Filtration afforded the
1
product as a white microcrystalline powder (195 mg, 92%). H
NMR (CDCl3):  2.93 (s, 6H, 3JPtH = 17 Hz, NCH3), 2.96–2.87 (m,
2H, NCH2), 2.86–2.75 (m, 2H, NCH2), 2.86 (s, 6H, 3JPtH = 42 Hz,
NCH3) ppm. 19F NMR (CDCl3):  −121.71 (m, 2F, 3JPtF = 344 Hz,
o-ArF), −162.06 (m, 1F, p-ArF), −164.37 (m, 2F, m-ArF) ppm.
Anal. Calcd. for C12H16ClF5N2Pt: %C 28.05; %H 3.14. Found: %C
28.01; %H 3.11. X-Ray diffraction quality crystals were grown
from CH2Cl2/hexane.
[1,2-bis(dimethylamino)ethane](chloro)pentafluorophenyl-
palladium(II) 3a. To a solution of 1b (100 mg, 0.13 mmol) in THF
(10 mL) was added tmeda (38 L, 0.26 mmol) and the reaction was
heated at reflux for 2 h. The solution was cooled and stirred over-
night at room temperature. The solvent was removed in vacuo. The
residue was extracted with hexane to afford the product as a pale
yellow powder (88 mg, 82%). 1H NMR (CDCl3):  2.82–2.69 (m,
4H, NCH2), 2.77 (s, 6H, NCH3), 2.63 (s, 6H, NCH3) ppm. 19F NMR
(CDCl3):  −121.02 (m, 2F, o-ArF), −160.45 (dd, 1F, 3JFF = 20 Hz,
4JFF = 20 Hz, p-ArF), −163.24 (m, 2F, m-ArF) ppm. Anal. Calcd.
{1,2-bis[3,5-bis(trifluoromethyl)phenylimino]-1,2-dimethyl-
ethane}(chloro)(pentafluorophenyl)platinum(II) 4b. To a solu-
tion of 2b (100 mg, 0.10 mmol) in toluene (10 mL) was added
1,2-bis[3,5-bis(trifluoromethyl)phenylimino]-1,2-dimethylethane
(110 mg, 0.22 mmol) in CHCl3 (10 mL). The reaction mixture was
heated at reflux for 1 h and then stirred overnight at room tem-
perature. The solvent was removed in vacuo. Recrystallization from
CH2Cl2/hexane afforded the product as an orange microcrystalline
1
powder (67 mg, 36%). H NMR (CDCl3):  7.97 (s, 1H, p-ArH),
2 7 2 4
D a l t o n T r a n s . , 2 0 0 4 , 2 7 2 0 – 2 7 2 7

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[1,2-bis(dimethylphosphino)ethane](iodo)(pentafluoro-
phenyl)palladium(II) 6c. To a suspension of 5 (200 mg,
0.35 mmol) in benzene (10 mL) was added a solution of dmpe
(64 L, 0.38 mmol) and iodopentafluorobenzene (51 L,
0.38 mmol) in benzene. The reaction mixture was heated at reflux
for 2 h. The solution was cooled and filtered through Celite. The
solvent of the filtrate was removed in vacuo, and the residue was
extracted with hot hexanes until no color persisted. The resulting
pale yellow powder was recrystallized from CH2Cl2/hexane to
afford the product as a pale yellow microcrystalline powder (103
7.75 (s, 1H, p-ArH), 7.74 (s, 2H, o-ArH), 7.45 (s, 2H, o-ArH),
2.17 (s, 3H, NC(CH3)), 1.71 (s, 3H, NC(CH3)) ppm. 19F NMR
(CDCl3):  −63.15 (s, 6F, CF3), −63.65 (s, 6F, CF3), −121.45 (m, 2F,
3JPtF = 317 Hz, o-ArF), −160.26 (m, 1F, p-ArF), −163.85 (m, 2F, m-
ArF) ppm. Anal. Calcd. for C26H12ClF17N2Pt: %C, 34.47; %H, 1.34.
Found: %C, 34.26; %H, 1.36.
[1,2-bis(dimethylphosphino)ethane](chloro)(pentafluoro-
phenyl)platinum(II) 4c. To a solution of 2b (100 mg, 0.10 mmol)
in chloroform (10 mL) was added a solution of dmpe (40 L,
0.24 mmol) in toluene (10 mL) and the reaction mixture was heated
at reflux for 1 h, then stirred at room temperature overnight. The
solvent was removed in vacuo. The residue was recrystallized form
CHCl3/hexane to afford the product as a white powder (108 mg,
1
mg, 54%). H NMR (CDCl3):  2.07–1.86 (m, 4H, PCH2), 1.85
2
2
(d, 6H, JPH = 10 Hz, PCH3), 1.48 (d, 6H, JPH = 11 Hz, PCH3)
ppm. 19F NMR (CDCl3):  −115.93 (m, 2F, o-ArF), −160.15 (t, 1F,
3JFF = 20 Hz, p-ArF), −162.80 (m, 2F, m-ArF) ppm. 31P{1H} NMR
(CDCl3):  46.93 (m, P trans to I), 38.74 (m, P trans to C6F5) ppm.
Anal. Calcd. for C12H16F5IP2Pd: %C, 26.12; %H, 2.94. Found: %C,
25.93; %H, 2.81.
1
96%). H NMR (CDCl3):  2.08–1.75 (m, 4H, PCH2), 1.76 (d,
6H, 2JPH = 11 Hz, 3JPtH = 22 Hz, PCH3), 1.62 (d, 6H, 2JPH = 12 Hz,
3JPtH = 22 Hz, PCH3) ppm. 19F NMR (CDCl3):  −119.22 (m, 2F,
3JPtF = 140 Hz, o-ArF), −161.06 (m, 1F, 3JFF = 20 Hz, 3JFF = 20 Hz,
p-ArF), −163.26 (m, 2F, m-ArF) ppm. 31P{1H} NMR (CDCl3): 
35.79 (m, 1JPtP = 1117 Hz, Ptrans to C6F5), 23.43 (d, 1JPtP = 1798 Hz,
3JPP = 5 Hz, Pcis to C6F5) ppm.Anal. Calcd. for C12H16ClF5P2Pt.0.75
CH2Cl2: %C, 25.04; %H, 2.89. Found: %C, 25.34; %H, 2.91. X-Ray
diffraction quality crystals were grown from CH2Cl2/hexane.
Aqua[1,2-bis(dimethylphosphino)ethane](pentafluoro-
phenyl)platinum(II) triflate 7a. A suspension of 4c (100 mg,
0.18 mmol) in chloroform (10 mL) was added to a suspension of
AgO3SCF3 (47 mg, 0.18 mmol) in chloroform (5 mL). The reac-
tion mixture was stirred at room temperature for 4 h. The solution
was filtered through Celite, and the volume of the supernatant was
reduced in vacuo to 5 mL. Toluene (10 mL) was added and the
remaining chloroform was removed in vacuo. The resulting white
crystalline powder was obtained by filtration (67 mg, 54%). 1H NMR
(CDCl3):  2.86 (ds, 2H, H2O), 2.45–2.12 (m, 4H, PCH2), 1.87 (d,
6H, 2JPH = 11 Hz, 3JPtH = 20 Hz, PCH3), 1.79 (d, 6H, 2JPH = 13 Hz,
3JPtH = 53 Hz, PCH3) ppm. 19F NMR (CDCl3):  −79.21 (s, 3F,
[1,2-bis(dicyclohexylphosphino)ethane](chloro)(pentafluoro-
phenyl)platinum(II) 4d. To a solution of 2b (200 mg, 0.21 mmol)
in chloroform (10 mL) was added a solution of dcpe (183 mg,
0.43 mmol) in toluene (10 mL) and the reaction mixture was heated
at reflux for 1 h, then stirred at room temperature overnight. The
solvent was reduced in volume in vacuo to 5 mL and hexane was
added. Filtration afforded the product as a white powder (325 mg,
3
SO3CF3), −119.63 (m, 2F, JPtF = 262 Hz, o-ArF), −161.73 (bs,1F,
p-ArF), −164.34 (bs, 2F, m-ArF) ppm. 31P{1H} NMR (CDCl3): 
40.27 (m, 1JPtP = 2374 Hz, P trans to C6F5), 19.69 (s, 1JPtP = 3842 Hz,
P cis to C6F5) ppm. Anal. Calcd. for C13H18F8O4P2PtS: %C, 22.98;
%H, 2.68. Found: %C, 22.38; %H, 2.56. X-ray diffraction quality
crystals were grown from CH2Cl2/hexane.
1
96%). H NMR (CDCl3):  2.48–2.20 (m, 4H, PCH2), 2.08–1.12
(m, 44H, PC6H11) ppm. 19F NMR (CDCl3):  −118.29 (m, 2F,
3JPtF = 327 Hz, o-ArF), −161.86 (m, 1F, p-ArF), −163.55 (m, 2F,
4JPtF = 114 Hz, m-ArF) ppm. 31P{1H} NMR (CDCl3):  65.34 (m,
1JPtP = 2295 Hz, P trans to C6F5), 59.92 (s, 1JPtP = 3720 Hz, P cis to
C6F5) ppm. Anal. Calcd. for C32H48ClF5P2Pt.0.5CH2Cl2: %C, 45.24;
%H, 5.74. Found: %C, 44.81; %H, 5.72. X-Ray diffraction quality
crystals grown from CH2Cl2/hexane.
Aqua[1,2-bis(dicyclohexylphosphino)ethane](pentafluoro-
phenyl)platinum(II) triflate 7b. To a suspension of AgOTf
(32 mg, 0.13 mmol) in CHCl3 (5 mL) was added a solution of 4d
(100 mg, 0.13 mmol) in CHCl3 (5 mL) dropwise at room tempera-
ture. The reaction mixture was stirred at room temperature for 4 h.
The solution was filtered through Celite and the volume of the
solvent was reduced to 5 mL in vacuo. Hexane was added and the
solvent reduced in volume in vacuo until crystallization was com-
plete. Filtration afforded the product as a white crystalline powder
(100 mg, 82%). 1H NMR (CDCl3):  2.42–2.22 (m, 4H, PCH2 and
CH2 from C6H11), 2.22 (bs, 2H, OH2), 2.10–1.12 (m, 42H, PC6H11),
0.85–0.78 (m, 2H, PCH2) ppm. 19F NMR (CDCl3):  −78.21 (s, 3F,
SO3CF3), −119.12 (m, 2F, 3JPtF = 264 Hz, o-ArF), −159.27 (m, 1F,
p-ArF), −163.23 (m, 2F, m-ArF) ppm. 31P{1H} NMR (CDCl3): 
71.30 (m, 1JPtP = 2332 Hz, Ptrans to C6F5), 53.63 (s, 1JPtP = 4298 Hz,
P cis to C6F5) ppm. Anal. calcd. for C33H50F8O4P2PtS.CH2Cl2: %C,
39.38; %H, 5.06. Found: %C, 38.92; %H, 4.80.
[1,2-bis(dimethylamino)ethane](iodo)(pentafluorophenyl)-
palladium(II) 6a. To a solution of 5 (200 mg, 0.35 mmol) in
benzene (10 mL) was added iodopentafluorobenzene (51 mL,
0.38 mmol) and tmeda (58 mL, 0.38 mmol) and the reaction mixture
was heated at reflux for 2 h. The solution was cooled and filtered
through Celite. The solvent was removed in vacuo and the residue
extracted with hot hexanes until no color persisted in the washings.
The product was recrystallized from CH2Cl2/hexane to afford the
product as a pale orange powder (154 mg, 86%). 1H NMR (CDCl3):
 2.88 (s, 6H, NCH3), 2.74 (m, 4H, NCH2), 2.54 (s, 6H, NCH3) ppm.
19F NMR (CDCl3):  −118.21 (m, 2F, o-ArF), −160.34 (m, 1F, p-
ArF), −163.47 (m, 2F, m-ArF) ppm.Anal. Calcd. for C12H16F5IN2Pd:
%C, 27.90; %H, 3.13. Found: %C, 27.98; %H, 2.95.
[1,2-bis(2,6-dimethylphenylimino)ethane](iodo)(pentafluoro-
phenyl)palladium(II) 6b. To a solution of 5 (200 mg, 0.35 mmol)
in benzene (10 mL) was added dmpe (101 mg, 0.38 mmol) and
iodopentafluorobenzene (51 L, 0.38 mmol). The reaction mixture
was heated at reflux for 2 h. The solution was filtered through Celite
and the solvent was removed in vacuo. The residue was extracted
with hot hexanes until no color persisted in the washings. Recrys-
tallization from CH2Cl2/hexane afforded the product as an orange
microcrystalline powder (204 mg, 86%). 1H NMR (CDCl3):  8.27
(s, 1H, NCH), 8.17 (s, 1H, NCH), 7.21 (m, 4H, m-ArH), 7.05
(m, 1H, p-ArH), 6.96 (m, 1H, p-ArH), 2.41 (s, 6H, o-ArCH3), 2.29
(s, 6H, o-ArCH3) ppm. 19F NMR (CDCl3):  −115.80 (m, 2F, o-
ArF), −160.81 (t, 1F, 3JFF = 20 Hz, p-ArF), −164.14 (m, 2F, m-ArF)
ppm. Anal. Calcd. for C24H20F5IN2Pd: %C 43.36; %H 3.04. Found:
%C 43.54; %H 3.01. X-Ray diffraction quality crystals were grown
from CH2Cl2/hexane.
[1,2-bis(dimethylphosphino)ethane]bis(pentafluorophenyl)-
palladium(II) 8. Method 1. To a suspension of AgOTf (56 mg,
0.22 mmol) in CHCl3 (10 mL) was added a suspension of 3c
(100 mg, 0.22 mmol) in CHCl3 (10 mL) dropwise with stirring.
After the addition was complete, the reaction mixture was stirred
at room temperature for 2 h. The solution was filtered through
Celite and the solvent reduced in volume in vacuo to 5 mL. Toluene
(10 mL) was added and the solvent reduced in volume in vacuo
until precipitation was complete. Filtration afforded the product
1
as a white powder (48 mg, 76%). H NMR (CD2Cl2):  1.95 (m,
2
4H, PCH2), 1.43 (d, 12H, JPH = 10 Hz, PCH3) ppm. 19F NMR
3
(CD2Cl2):  −115.61 (m, 4F, o-ArF), −162.52 (t, 2F, JFF = 19 Hz,
p-ArF), −164.26 (m, 4F, m-ArF) ppm. 31P{1H} NMR (CD2Cl2): 
36.31 (m) ppm. Anal. Calcd. for C18H16F10P2Pd: %C, 36.60; %H,
2.34. Found: %C, 36.27; %H, 2.75.
D a l t o n T r a n s . , 2 0 0 4 , 2 7 2 0 – 2 7 2 7
2 7 2 5

View Article Online
2
2
Method 2. To a solution of [Pd(C6F5)2(tht)2] 1a (100 mg,
0.16 mmol) in THF (5 mL) was added a solution of dmpe (28 L,
0.17 mmol) in THF (5 mL) and the reaction was stirred at room
temperature for 4 h. The solvent was removed in vacuo. The residue
was recrystallized from CH2Cl2/hexanes to afford the product as a
white powder (84 mg, 88%).
and PCH2), −0.30 (ddm, 1H, JP(cis)H = 4.5 Hz, JP(trans)H = 165 Hz,
1JPtH = 1036 Hz, PtH) ppm. 19F NMR (benzene-d6):  −114.98
2
(m, 2F, JPtF = 400 Hz, o-ArF), −164.50 (m, 1F, p-ArF), −165.30
(m, 2F, 4JPtF = 41 Hz, m-ArF) ppm. 31P{1H} NMR (benzene-d6): 
74.45 (sept, J = 8.5 Hz, 1JPtP = 2482 Hz, P trans to C6F5), 65.50 (s,
1JPtP = 1777 Hz, P cis to C6F5) ppm. Anal. Calcd. for C32H49F5P2Pt:
%C, 48.90; %H, 6.30. Found: %C, 48.71; %H, 5.96.
[1,2-bis(dimethylphosphino)ethane]bis(pentafluorophenyl)-
platinum(II) 10. Method 1. To a suspension of AgOTf (25 mg,
0.1 mmol) in CHCl3 (10 mL) was added a solution of 4c (50 mg,
0.1 mmol) in CHCl3 (10 mL), and the reaction mixture was stirred
at room temperature for 2 h. The solution was filtered through
Celite. The resulting solution was then stirred at room temperature
for 3 weeks. The solution was filtered and the solvent removed in
vacuo. Recrystallization from CH2Cl2/hexane afforded the product
as a colorless crystalline solid (22 mg, 61%). 1H NMR (CDCl3): 
1.94–1.80 (m, 4H, PCH2), 1.54 (d, 12H, 2JPH = 10 Hz, 3JPtH = 28 Hz,
Crystallographic structural determinations. Diffraction inten-
sity data were collected with a Bruker SmartApex CCD diffractom-
eter. Crystal, data collection, and refinement parameters are given
in Table 1. The space groups were chosen based on the systematic
absences (4c, 4d), systematic absences and intensity statistics (3a,
4a, 8), and intensity statistics (6b, 7a, 11b). The structures were
solved using the direct methods, completed by subsequent differ-
ence Fourier syntheses, and refined by full matrix least-squares
procedures on F2. SADABS absorption corrections were applied
to all data, except 7a (Tmin/Tmax = 0.280) where absorption correc-
tion was done by DIFABS. In the crystal structure of 4d, the highly
disordered CH2Cl2 solvate molecule was treated by SQUEEZE.22
Corrections of the X-ray data by SQUEEZE (187 electron/cell)
were close to the required value (168 electron/cell for one CH2Cl2
molecule in a general position). All non-hydrogen atoms were re-
fined with anisotropic displacement coefficients, except the C(7)
and C(8) carbon atoms in 3a and 4a (disordered over two positions
in ratio 45/55) and the C, Cl atoms of CH2Cl2 solvent molecule in
4c (disordered around a center of symmetry), which were refined
with isotropic thermal parameters. Hydrogen atoms were treated
as idealized contributions, except all H atoms in 6b and the H(1)
atom in 11b, which were found from the F-map and refined with
isotropic thermal parameters, and the H atoms of water molecules
in 7a where the H atoms were not taken in consideration. The Flack
parameters for 3a and 4a are 0.04(6) and 0.01(1), respectively. The
b and c parameters and  and  angles for the unit cell of 7a, as well
as the value of Z′, suggest the possibility of higher symmetry, but
none was found. The four independent molecules found in 7a may
be related to the asymmetrical arrangement of CF3SO3 groups in the
crystal structure. All software and sources of scattering factors are
contained in the SHELXTL (5.10) program package (G. Sheldrick,
Bruker XRD, Madison, WI).
3
PCH3) ppm. 19F NMR (CDCl3):  −118.18 (m, 4F, JPtF = 332 Hz,
o-ArF), −162.02 (m, 2F, p-ArF), −163.83 (m, 4F, 4JPtF = 70 Hz, m-
1
ArF) ppm. 31P{1H} NMR (CDCl3):  28.33 (bm, JPtP = 2246 Hz)
ppm. Anal. Calcd. for C18H16F10P2Pt: %C, 31.82; %H, 2.38. Found:
%C, 31.72; %H, 2.37.
Method 2. To a solution of [Pt(C6F5)2(tht)2] 2a (75 mg, 0.11 mmol)
in THF (5 mL) was added a solution of dmpe (20 L, 0.12 mmol)
in THF (5 mL) and the reaction mixture was stirred for 4 h at room
temperature. The solvent was removed in vacuo. The residue was
recrystallized from CH2Cl2/hexanes to give the product as a white
powder (55 mg, 76%).
Bis[1,2-bis(dicyclohexylphosphino)ethane]palladium(II)
triflate 9. To a suspension of AgOTf (35 mg, 0.14 mmol) in CHCl3
(10 mL) was added a solution of 3d (100 mg, 0.14 mmol) in CHCl3
(10 mL) dropwise. The reaction mixture was stirred at room tem-
perature for 2 h, after which time the solution was filtered through
Celite. Toluene (10 mL) was added and the solution was reduced in
volume invacuo untilprecipitationwascomplete. Filtrationafforded
the product as a white powder (74 mg, 80%). 1H NMR (CD2Cl2): 
2.40–2.04 (m, 12 H, 2 × PCH2 and 2 × CH2 from C6H11), 2.00–1.68
(m, 18H, C6H11), 1.56–1.18 (m, 22H, C6H11) ppm. 19F NMR
(CD2Cl2):  −78.94 (s, 3F, CF3SO3) ppm. 31P{1H} NMR (CD2Cl2): 
106.71 (bs) ppm. Anal. Calcd. for C54H96F6O6P4PdS2·4CHCl3: %C,
40.32; %H, 5.79. Found: %C, 39.94; %H, 6.11.
CCDC reference numbers 227751–227758 for complexes 3a, 4a,
4c, 4d, 6b, 7a, 8, and 11b.
See http://www.rsc.org/suppdata/dt/b4/b406602b/ for crystallo-
graphic data in CIF or other electronic format.
[1,2-bis(dimethylphosphino)ethane](hydrido)(pentafluoro-
phenyl)platinum(II) 11a. To a suspension of 4c (150 mg,
0.27 mmol) in THF (10 mL) was added NaBH4 (12 mg, 0.32 mmol)
and the reaction mixture was heated at reflux for 12 h. The reac-
tion mixture was cooled to room temperature and the solvent was
removed in vacuo. The residue was extracted with ether. The sol-
vent of the combined extracts was removed in vacuo to afford the
product as an off-white crystalline powder (83 mg, 59%). 1H NMR
(C6D6):  1.02 (d, 6H, 2JPH = 10 Hz, 3JPtH = 34 Hz, PCH3), 0.88 (dd,
6H, 2JPH = 9 Hz, 4JHH = 1 Hz, 3JPtH = 20 Hz, PCH3), 0.81–0.58 (m,
4H, PCH2), −1.48 (ddm, 1H, JP(trans)H = 200 Hz, JP(cis)H = 17 Hz,
1JPtH = 1080 Hz, PtH) ppm. 19F NMR (C6D6):  −113.77 (m, 2F,
3JPtF = 402 Hz, o-ArF), −163.72 (m, 1F, p-ArF), −164.81 (m, 2F,
m-ArF) ppm. 31P{1H} NMR (C6D6):  30.46 (s, 1JPtP = 1616 Hz, P
trans to H), 24.27 (m, 1JPtP = 2362 Hz, P trans to C6F5) ppm. Anal.
Calcd. for C12H17F5P2Pt: %C, 28.08; %H, 3.34. Found: %C, 27.88;
%H, 2.91.
Acknowledgements
RPH is grateful to the National Science Foundation and the Pe-
troleum Research Fund, administered by the American Chemical
Society, for financial support.
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