Diphosphazane supported platinum(II) triflate, amine, and amido complexes: Synthesis and X-ray crystal structures

Article abstract of DOI:10.1016/S0277-5387(02)00979-8

Treatment of L₂PtC1₂ (L₂ = MeN[P(OPh₂)]₂) with AgSO₃CF₃ gives the triflate complex L₂Pt(SO₃CF₃)₂ (1). Addition of 2,6-dimethylaniline

Full text of DOI:10.1016/S0277-5387(02)00979-8

Polyhedron 21 (2002) 1305ꢂ1310
/
www.elsevier.com/locate/poly
Diphosphazane supported platinum(II) triflate, amine, and amido
complexes: synthesis and X-ray crystal structures
Aibing Xia, Paul R. Sharp *
125 Chemistry, University of Missouri, Columbia, MO 65211, USA
Received 24 January 2002; accepted 19 March 2002
Abstract
Treatment of L2PtCl2 (L2ꢀ
dimethylaniline to 1 in CH2Cl2 gives the monomeric diamine complex [L2Pt(NH2Ar)2](SO3CF3)2 (2, Arꢀ
reaction of 1 with lithium 2,6-dimethylanilide gives the dimeric bridging amido complex [L2Pt(m-NHAr)]2(SO3CF3)2 (3 Arꢀ
/
MeN[P(OPh2)]2) with AgSO3CF3 gives the triflate complex L2Pt(SO3CF3)2 (1). Addition of 2,6-
2,6-Me2C6H3), while
2,6-
/
/
Me2C6H3). Cyclometalation is observed when 1 is treated with lithium 2,4,6-triphenylanilide yielding the neutral complex
L2Pt{NH[2-(3,5-Ph2C6H2)C6H4]} (4). The structures of all four complexes were determined by X-ray diffraction methods. All
display the expected four-coordinate square planar Pt geometry. The amine (2) and amido (3) complexes show NÃ
/H hydrogen
bonding to the triflate anions. # 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Amido; Amine; Triflate; Platinum; Diphosphazane; Cyclometalation
1. Introduction
2. Results and discussion
Late transition metal amido complexes [1] have
attracted considerable interest for their potential in
organic synthesis [2] and for their usefulness as synthetic
precursors [1,3,4]. Platinum(II) and palladium(II) amido
complexes have been widely studied and their structural
features and reactivities found to be influenced by
differences in the supporting ligands [2,5,6]. A common
feature of amido complexes is a relatively high amido
ligand electron density. Since one of our major interests
is deprotonation of amido ligands to imido ligands we
are interested in factors that reduce amido ligand
electron density and enhance acidity. Diphosphazanes
(RN(PX2)2) are versatile supporting ligands that can be
easily modified on both nitrogen and phosphorus
centers to tune steric and electronic properties [7].
Here we report the synthesis and structures of several
platinum(II) complexes, including amido complexes,
employing the supporting diphosphazane ligand
MeN[P(OPh)2]2.
The high lability of the triflate ligand makes metal
triflate complexes excellent synthetic precursors [8]. The
triflate complex L2Pt(SO3CF3)2 (1) is readily obtained
from the reaction of L2PtCl2 (L2ꢀMeN[P(OPh)2]2) [9]
/
with AgSO3CF3 in CH2Cl2 at ambient temperatures
(Scheme 1). The 31P NMR signal of the diphosphazane
ligand shifts upfield by about 36 ppm (from 43.5 ppm
for the dichloride to 7.5 ppm for the triflate). Along with
this upfield shift, the PtÃ
almost 1000 Hz (from 5036 to 6008 Hz). These data
imply a stronger PÃPt interaction consistent with the
/P coupling constant increases
/
expected weaker trans-influence of the triflate ligand
[10]. An X-ray crystal structure analysis of 1 (Fig. 1,
Table 1) shows the expected square planar Pt center with
a cis-disposition of the triflate ligands. Selected dis-
tances and angles are given in Table 2. There are two
known structures of Pt(II) triflate complexes with a
phosphorus ligand trans to the triflate ligand. The most
closely related to 1 is the diphosphine complex {1,2-
(PMePh)2C6H4}Pt(OTf)2 [11]. The PtÃ
/
O bond lengths
˚
in this complex are 2.142(9) and 2.091(8) A, similar to
˚
those in 1 (2.080(3) and 2.096(3) A). The PtÃ
of 136.1(5)8 and 131.1(6)8 are slightly greater than those
in 1 (130.19(17)8 and 128.06(16)8). The more open PtÃ
/
OÃ
/
S angles
* Corresponding author. Tel.: ꢁ
2754.
E-mail address: sharpp@missouri.edu (P.R. Sharp).
/
1-573-882-7715; fax: ꢁ1-573-882-
/
/
0277-5387/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.
PII: S 0 2 7 7 - 5 3 8 7 ( 0 2 ) 0 0 9 7 9 - 8

1306
A. Xia, P.R. Sharp / Polyhedron 21 (2002) 1305ꢂ1310
/
As expected, the triflate ligands of 1 are labile and 1
reacts readily with 2,6-dimethylaniline at ambient tem-
perature to afford the diamine complex [L2Pt(NH2Ar)2]-
(SO3CF3)2 (2, Arꢀ
31P NMR signal at 16.5 ppm with a PtÃ
constant of 4900 Hz. This decrease in the PtÃ
/
2,6-Me2C6H3). Complex 2 gives a
P coupling
P coupling
/
/
constant from that of 1 and L2PtCl2 is indicative of the
stronger trans-influence of the amine ligand relative to
the triflate and chloride ligands [10]. The NH peak is
1
observed in the H NMR spectrum of 2 at 7.04 ppm
(CD2Cl2), shifted downfield by about 2 ppm from that
of the free ligand in the same solvent. An X-ray crystal
structure analysis of 2 (Fig. 2, Table 1) shows the
expected square planar Pt center with a cis-disposition
of the amine ligands. The amine ligands interact with the
two triflate anions through bifurcated hydrogen bonds.
Metrical parameters are given in Table 3. Comparison
structures with mononuclear cis-P2PtN2 cores are
mostly limited to complexes incorporating the amine
nitrogen in a chelate ring. An exception is the simple
ammonia complex cis-[(Ph3P)2Pt(NH3)2](NO3)2 [13].
This complex shows a similar hydrogen bonding pattern
of the coordinated amine to the counter anion, and an
˚
average PtÃ
/
N distance of 2.098(9) A. Structures incor-
porating the amine into a chelate ring have average PtÃ
/
˚
N distances ranging from 2.07(11) to 2.110(8) A [14].
N distances of 2 are in this range (2.118(4) and
The PtÃ
/
˚
2.129(4) A).
Scheme 1.
Attempts to deprotonate 2 with LiN(SiMe3)2 to
obtain an amido complex were not successful. 1H
NMR spectra of the reaction mixtures showed the loss
of the diphosphazane NÃ/Me triplet signal indicating
disruption of the diphosphazane ligand, probably
through nucleophilic attack on the phosphorus center.
As an alternative to the formation of an amido
complex by deprotonation of 2, 1 was treated with
lithium 2,6-dimethylanilide in THF at ꢃ
amido-bridged dimer [L2Pt(m-NHAr)]2(SO3CF3)2 (3,
Arꢀ2,6-Me2C6H3) was obtained as the only isolated
product with anilide to Pt ratios of 1:1ꢂ2:1 (Scheme 1).
Complex 3 gives a 31P signal at 29.9 ppm with a PtÃ
/
30 8C. The
/
/
/P
1
coupling constant of 4628 Hz. The H NMR spectrum
Fig. 1. ORTEP drawing of L2Pt(SO3CF3)2 (1). Hydrogen atoms are
omitted for clarity. Atoms, except phenoxide atoms and the NÃMe
carbon (arbitrary spheres), are represented by 50% probability thermal
shows an NÃH peak at 4.93 ppm, an upfield shift
/
/
compared with the monomeric diamine complex 2 and
suggestive of greater electron density on the nitrogen
centers in the anilido dimer 3. However, this shift is
lower than that observed for analogous diphosphine
ellipsoids.
OÃ/S angle of {1,2-(PMePh)2C6H4}Pt(OTf)2 may result
complexes (4.6ꢂ2.6 ppm) [6] suggesting that the reduced
/
from steric crowding. Such factors are absent in 1 with
its smaller bite angle diphosphazane and less sterically
demanding OPh phosphorus substituents. The second
complex for comparison is the diphosphine complex
donor properties of the diphosphazane ligand result in
less electron density at the amido ligand. An X-ray
crystal structure analysis of 3 (Figs. 3 and 4, Table 1)
shows the expected edge-shared dimer with a syn-
orientation of the amido aryl groups. One triflate anion
is hydrogen-bonded to the amido groups. The Pt2N2
{(C2F5)2PCH2CH2P(C2F5)2}Pt(Me)(OTf) [12]. The PtÃ
/
˚
O distance (2.090(6) A) and the PtÃ
/
OÃ/S angle
(130.2(3)8) in this complex are almost identical to those
of 1 suggesting minimal steric congestion, as in 1.
core is slightly bent at the NÃ
/
N hinge. Factors involved
in the bending of di-bridged d8-square-planar dimers of

A. Xia, P.R. Sharp / Polyhedron 21 (2002) 1305ꢂ
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1307
Table 1
Crystallographic and data collection parameters at 173 K
a
d
d
Formula
C27H23F6N O10P2PtS2 (1) C43H45F6N3O10P2PtS2 (2) C68H66F6N4O14P4Pt2S2 (3).DME
C49H40N2O4P2Pt (4).1.5DME
Color/habit
Size (mm)
colorless/block
0.5ꢄ0.2ꢄ0.2
triclinic
colorless/needle
0.5ꢄ0.05ꢄ0.05
monoclinic
Cc (4)
yellow/prism
0.2ꢄ0.15ꢄ0.15
monoclinic
P21/n (4)
19.809(3)
20.117(3)
21.242(3)
90
yellow/plate
0.2ꢄ0.2ꢄ0.05
triclinic
Crystal system
Space group (Z)
¯
1 (2)
¯
P1 (2)
P/
/
˚
a (A)
10.7182(6)
11.2575(6)
15.7721(9)
82.078(1)
83.812(1)
64.575(1)
13 552
13.185(2)
17.330(2)
21.515(3)
90
13.3686(6)
13.3859(6)
15.9724(7)
91.497(1)
108.834(1)
112.315(1)
19 793
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
Total reflections
Unique/Rint
101.394(7)
90
14 825
112.780(2)
90
48 486
7337/0.026
8833/0.028
8157
17 226/0.056
11 169
10 675/0.029
9391
Observed (ꢀ2s(I)) 6501
umax/%measured
b
R1
wR2 c/No. var.
27.13/97.3
0.0249
0.0582/443
27.13/98.9
0.0292
0.0709/604
27.19/99.2
0.0381
0.0780/963
27.15/97.7
0.0300
0.0691/608
a
system (omega scans), SADABS absorption correction, l (Mo Ka)ꢀ0.71073 A, refined on Fo2, H atoms riding/refined.
˚
R1ꢀ(ajjCFCojDꢃjFcj)/ajFoj.
Siemens
b
c
wR2ꢀ[(a(Fo2ꢃFc2)2)/a w(Fc2)2]1/2 with weightꢀ1/[s2(Fo2)ꢁ(xP)2ꢁyP]; xꢀ0.0333, yꢀ0 for 1; xꢀ0.0420, yꢀ4.7556 for 2; xꢀ0.0299,
yꢀ0 for 3; xꢀ0.0379, yꢀ0 for 4; Pꢀ(Fo 2ꢁ2Fc2)/3.
d
Solvent of crystallization, DMEꢀMeOCH2CH2OMe (C4H10O2).
Table 2
˚
Selected distances (A) and angles (8) for L2Pt(OTf)2 (1)
Bond distances
Pt1ÃO5
Pt1ÃO9
Pt1ÃP2
Pt1ÃP1
S1ÃO7
O5ÃS1
S1ÃC2
S1ÃO6
S2ÃO8
2.080(3)
2.096(3)
2.182(1)
2.190(1)
1.416(3)
1.485(3)
1.814(5)
1.422(3)
1.419(3)
S2ÃO10
S2ÃO9
S2ÃC3
F5ÃC3
F1ÃC2
F6ÃC3
F3ÃC2
F4ÃC3
F2ÃC2
1.430(3)
1.487(3)
1.819(5)
1.327(5)
1.325(5)
1.333(6)
1.326(6)
1.325(6)
1.311(5)
Bond angles
O5ÃPt1ÃP2
O5ÃPt1ÃO9
O5ÃPt1ÃP1
O9ÃPt1ÃP2
Fig. 2. ORTEP drawing of [L2Pt(NH2Ar)2](SO3CF3)2 (2, Arꢀ2,6-
/
176.53(8)
78.21(11)
105.65(8)
104.96(8)
P2ÃPt1ÃP1
O9ÃPt1ÃP1
S1ÃO5ÃPt1
S2ÃO9ÃPt1
71.21(3)
176.03(7)
130.19(17)
128.06(16)
Me2C6H3). Hydrogen atoms, except the amine hydrogen atoms, are
omitted for clarity. Arbitrary spheres represent the atoms except for
the Pt, P, and N atoms, which are represented by 50% probability
thermal ellipsoids.
Table 3
this type have been studied [15]. Selected bond distances
and angles are given in Table 4 and are similar to those
of related structurally characterized amido complexes
with P2Pt(m-N)2PtP2 cores [6,16].
˚
Selected distances (A) and angles (8) for [L2Pt(NH2Ar)2](SO3CF3)2 (2,
Arꢀ2,6-Me2C6H3)
Bond lengths
Pt1ÃP1
Pt1ÃN2
P1ÃN1
N3ÃC1n
2.211(4)
2.118(4)
1.664(4)
1.472(6)
Pt1ÃP2
Pt1ÃN3
P2ÃN1
2.209(1)
2.129(4)
1.684(4)
1.475(6)
2ꢁ
Previous work has shown that [L2Pt(m-NHAr)]2
complexes can be converted to imido complexes by
deprotonation if L2 is the small bite-angle ligand
(Ph2P)2NMe [3]. We, therefore, anticipated that 3,
with its more weakly donating [(PhO)2P]2NMe ligand,
would deprotonate even more readily to produce an
N2ÃC1n2
Bond angles
P1ÃPt1ÃP2
Pt1ÃP1ÃN1
P1ÃN1ÃP2
70.85(5)
94.49(17)
99.69(25)
N2ÃPt1ÃN3
Pt1ÃP2ÃN1
86.24(16)
94.97(16)
imido complex. However, treatment of
3
with
LiN(SiMe3)2 does not give an imido complex but rather
appears to lead to disruption of the diphosphazane
ligand. As in the attempted deprotonation of 2 (see
above), this is indicated by the loss of the NÃ
/
Me triplet
signal in the 1H NMR spectrum of the reaction mixture.

1308
A. Xia, P.R. Sharp / Polyhedron 21 (2002) 1305ꢂ
/1310
Table 5
˚
Selected distances (A) and angles (8) for L2Pt{NH[2-(3,5-
Ph2C6H2)C6H4]} (4)
Bond lengths
Pt1ÃP1
Pt1ÃN2
P1ÃN1
2.284(2)
1.995(5)
1.673(6)
Pt1ÃP2
Pt1ÃC20
P2ÃN1
2.209(2)
2.049(6)
1.678(6)
Bond angles
P1ÃPt1ÃP2
Pt1ÃP1ÃN1
P1ÃN1ÃP2
69.48(6)
96.4(2)
99.7(3)
N2ÃPt1ÃC20
Pt1ÃP2ÃN1
89.9(2)
93.6(2)
Fig. 3. ORTEP drawing of the cationic portion of [L2Pt(m-
NHAr)]2(SO3CF3)2 (3, Arꢀ
the NÃH hydrogen atoms, are omitted for clarity. All atoms, except
phenoxide atoms and the NÃMe carbon (arbitrary spheres), are
/
2,6-Me2C6H3). Hydrogen atoms, except
L2Pt{NH[2-(3,5-Ph2C6H2)C6H4]} (4) was obtained
(Scheme 1). The 31P NMR spectrum of 4 shows two
/
/
represented by 50% probability thermal ellipsoids.
doublets (JPÃP
and 95.9 ppm (JPÃPt
with the small PtÃP coupling constant is assigned to the
ꢀ
/
49.1 Hz) at 70.8 ppm (JPÃPt
ꢀ3920 Hz)
/
ꢀ/1959 Hz). The high-shift doublet
/
phosphorus atom trans to the carbon atom consistent
with the strong trans-influence of a carbon anion [10].
An X-ray crystal structure analysis of 4 (Fig. 4, Table 1)
confirms the cyclometalation of the amido ligand.
Selected distances and angles are given in Table 5.
Remarkably, despite the commercial availability of the
aniline, this is apparently only the second report of a
transition metal complex formed from this aniline [17].
This is in sharp contrast to other terphenyl ligands, [18]
the related phenol, 2,6-Ph2C6H3OH, [19] and other
substituted anilines, [20] which have been used for the
preparation of a number of metal complexes. Cyclome-
talations, like that observed here, have been reported
with the phenoxo ligand 2,6-Ph2C6H3O for a number of
early transition metals [19] and for Sn [21] and Ge [22].
Two possible pathways to cyclometalation product 4
are considered in Scheme 2. Both begin by formation of
the amido triflate complex L2Pt(NHAr?)(OTf). This
species may loose a triflate anion to generate the
three-coordinate species [L2Pt(NHAr?)]ꢁ (A). (A
Fig. 4. ORTEP drawing of the cationic portion of L2Pt{NH[2-(3,5-
Ph2C6H2)C6H4]} (4). Hydrogen atoms, except the amine hydrogen
atoms, are omitted for clarity. Atoms, except phenoxide atoms and the
NÃMe carbon (arbitrary spheres), are represented by 50% probability
/
thermal ellipsoids.
Table 4
˚
Selected distances (A) and angles (8) for [L2Pt(m-NHAr)]2(SO3CF3)2 (3,
Arꢀ2,6-Me2C6H3)
Bond lengths
Pt1ÃPt2
Pt1ÃN3
Pt1ÃP2
Pt2ÃN3
Pt2ÃP4
3.1732(5)
2.104(4)
2.206(1)
2.104(4)
2.208(2)
Pt1ÃN2
Pt1ÃP1
Pt2ÃN2
Pt2ÃP3
2.115(4)
2.210(2)
2.113(4)
2.220(2)
Bond angles
P1ÃPt1ÃP2
P1ÃPt1ÃN2
P1ÃPt1ÃN3
P2ÃPt1ÃN2
P2ÃPt1ÃN3
N2ÃPt1ÃN3
P1ÃN1ÃP2
Pt1ÃN2ÃPt2
70.54(5)
106.3(1)
175.2(1)
176.8(1)
104.7(1)
78.53(15)
99.53(25)
97.26(15)
P3ÃPt2ÃP4
P3ÃPt2ÃN2
P3ÃPt2ÃN3
P4ÃPt2ÃN2
P4ÃPt2ÃN3
N2ÃPt2ÃN3
P3ÃN4ÃP4
Pt1ÃN3ÃPt2
70.77(5)
105.7(1)
175.7(1)
176.4(1)
105.7(1)
78.58(15)
100.6(3)
97.90(16)
In an effort to block dimer formation as observed in
3, 1 was treated with 2 equiv. of the bulky anilide
LiNH(2,4,6-Ph3C6H2). Instead of the expected mono-
nuclear diamido complex, cyclometalation product
Scheme 2.

A. Xia, P.R. Sharp / Polyhedron 21 (2002) 1305ꢂ
/1310
1309
Ni(II) analog of A has been isolated [23]). Three-
coordinate species are thought to be required for
significant cyclometalation rates in Pt(II) systems [24].
The second pathway requires formation of the terminal
single crystals suitable for X-ray diffraction were
obtained from CH2Cl2ꢂEt2O. Anal. Calc. (Found): C
/
33.90 (34.12), H 2.42 (2.41), N 1.46 (1.49)%. M.p.: 180ꢂ
/
1
3
182 8C. H NMR (CD2Cl2): 2.91 (t, JHÃP
3H, Me), 7.20ꢂ
(CD2Cl2): 31.71 (s, Me), 120.92 (t, JCÃP
of Ph), 127.85 (s, Cpara of Ph), 131.15 (s, Cmeta of Ph),
149.39 (t, JCÃP
4.0 Hz, Cipso of Ph). 31P (CD2Cl2): 7.49
(JPÃPt 6008 Hz).
ꢀ
/
13.3 Hz,
imido complex L2PtÄ
/
NAr? (B) either by deprotonation
/
7.41 (m, 20H, phenyl). 13C NMR
of L2Pt(NHAr?)(OTf) (or A) or formation of
L2Pt(NHAr?)2 followed by elimination of H2NAr?.
ꢀ2.4 Hz, Cortho
/
Addition of the CÃ
/
H bond across the PtÃ/N double
ꢀ
/
bond, a process known for terminal early transition
metal imido complexes, [25] would then yield 4.
Although never observed, terminal Pt(II) oxo complexes
analogous to B have been postulated [26] and a Ni(II)
analog of B has been recently reported [23]. Given the
lack of evidence for imido complex B, we favor the well-
established [24] electrophilic cyclometalation through
three-coordinate A. However, future work will be
directed at establishing the possible existence of A with
aryl groups that are less susceptible to cyclometalation
and supporting ligands (L2) that discourage approach of
the aryl group to the Pt center.
ꢀ
/
3.3. [L2Pt(NH2Ar)2](SO3CF3)2 (2, Arꢀ
/
2,6-
Me2C6H3)
2,6-dimethylaniline (0.032 g, 0.260 mmol) was added
to a solution of (L2Pt)(OTf)2 (0.126 g, 0.132 mmol) in
CH2Cl2 (2 ml ). The solution was stirred for 2 h at
ambient temperature. Addition of Et2O (10 ml )
afforded a white precipitate of the product. This was
collected by filtration, washed twice with Et2O (3 ml),
and dired in vacuo (0.135 g, 85.4%). Colorless single
crystals suitable for X-ray diffraction were obtained
from CH2Cl2ꢂEt2O. Anal. Calc. (Found): C 43.08
/
3. Experimental
(42.87), H 3.78 (3.87), N 3.50 (3.50)%. M.p.: 196ꢂ
/
1
3
200 8C. H NMR (CD2Cl2): 1.75 (t, JHÃP
ꢀ
/
12.0 Hz,
3.1. General procedures
3H, Me), 2.67 (s, 12H, Me), 7.04 (s, overlapped with Ph,
NH), 6.87ꢂ
7.49 (m, 30H, Ph). 13C NMR (CD2Cl2):
15.00, 18.11, 110.09, 119.63, 124.53, 126.95, 127.62. 31P
(CD2Cl2): 16.47 (Jꢀ4909 Hz).
/
Experiments were performed under a nitrogen atmo-
sphere in a Vacuum Atmospheres Corp. drybox. Sol-
vents were dried by standard techniques and stored
/
˚
under nitrogen over 4 A molecular sieves. The com-
3.4. [L2Pt(m-NHAr)]2(OTf)2 (3, Arꢀ2,6-Me2C6H3)
/
pounds 2,6-dimethylaniline, 2,4,6-triphenylaniline, and
AgSO3CF3 were purchased from Aldrich or Acros
Chemicals and were used as received. The lithium
anilides were prepared from the anilines and LiBun
A solution of lithium 2,6-dimethylanilide (0.010 g,
0.079 mmol) in THF (1 ml) was added to a solution of
(L2Pt)(OTf)2 (0.039 g, 0.040 mmol) in THF (1 ml) at ꢃ
/
(2.5 M) in hexane. L2ꢀ/MeN[P(OPh)2]2 and L2PtCl2
30 8C. The mixture was kept at ꢃ30 8C overnight then
/
were prepared by literature procedures [9]. NMR
spectra were recorded on a Bruker AMX-250 spectro-
warmed to ambient temperatures and the volume
reduced in vacuo. Et2O (10 ml) was added and the
resulting precipitate was filtered and washed with Et2O
(3 ml) to afford the pale yellow solid product (0.020 g,
50%). Yellow crystals for the X-ray analysis were
1
meter. H NMR (250 MHz) and 13C NMR (62.9 MHz)
spectra are referenced to TMS or to solvent impurities
referenced back to TMS. 31P NMR (101 MHz) spectra
are referenced to external 85% H3PO4. All NMR shifts
are in ppm with negative shift upfield from the reference.
Spectra were recorded at ambient temperatures (22 8C)
unless otherwise indicated. Melting points are uncor-
rected.
obtained from DMEꢂi
NMR (CD2Cl2): 2.13 (t, JHÃP
/
Pr2O. M.p.: 205ꢂ
/
208 8C. 1H
3
ꢀ
/
12.0 Hz, 6H, Me),
2.42 (s, 6H, Me), 3.52 (s, Me), 4.93 (bs, 2H, NH), 6.73ꢂ
/
7.45 (m, 26H, Ph). 13C NMR (CD2Cl2): 19.18, 22.97,
120.14, 120.21, 127.34, 129.10, 130.80, 130.99, 131.44,
149.49. 31P (CD2Cl2): 29.93 (JPÃPt
ꢀ4628 Hz).
/
3.2. Preparation of L2Pt(OTf)2 (1)
3.5. L2Pt{NH[2-(3,5-Ph2C6H2)C6H4]} (4)
Silver trifluoromethane sulfonate (0.257 g, 1.00 mmol)
was added to a suspension of L2PtCl2 (0.365 g, 0.500
mmol) in 2.0 ml of CH2Cl2. The mixture was stirred at
ambient temperature overnight and then filtered. Addi-
tion of Et2O (10 ml ) to the filtrate afforded a white
precipitate of the product. This was collected by
filtration, washed twice with Et2O (3 ml), and dried in
vacuo to give 0.400 g (83.5%) of white solid. Colorless
A solution of lithium 2,4,6-triphenylanilide (0.013 g,
0.040 mmol) in THF (1 ml) was added to a solution of
(L2Pt)(OTf)2 (0.020 g, 0.020 mmol) in THF (1 ml) at ꢃ
/
30 8C. The mixture was kept at ꢃ30 8C overnight and
/
the volume was reduced under reduced pressure. Et2O
(10 ml) was added and the precipitate was filtered and
washed with Et2O (3 ml) to afford a pale yellow solid

1310
A. Xia, P.R. Sharp / Polyhedron 21 (2002) 1305ꢂ1310
/
(b) M.S. Balakrishna, T.K. Prakasha, S.S. Krishnamurthy, U.
Siriwardane, N.S. Hosmane, J. Organomet. Chem. 390 (1990)
203.
(0.010 g, 50%). Yellow crystals for the X-ray analysis
were obtained from DMEꢂi
/
Pr2O. M.p.: 196ꢂ
/
200 8C.
8.0 Hz, 3H, Me of
7.74 (38H, Phenyl). 13C NMR
1H NMR (CD2Cl2): 3.00 (t, JHÃP
ꢀ
/
3
[10] (a) T.G. Appleton, H.C. Clark, L.E. Manzer, Coord. Chem. Rev.
10 (1973) 335;
L2), 6.60 (1H, NH), 6.64ꢂ
/
(CD2Cl2): 14.27, 126.62, 126.72, 127.28, 127.77, 128.33,
128.62, 128.66, 129.10, 129.38, 131.10, 140.18, 140.95,
(b) F.R. Hartley, The Chemistry of Platinum and Palladium,
Appl. Sci. Publishers, 1973;
141.25. 31P (CD2Cl2): 70.80 (2JPÃP
3920 Hz, trans to N), 95.86 (2JPP
1959 Hz, trans to C).
ꢀ
/
49.1 Hz, JPÃPt
ꢀ
/
(c) E.M. Shustorovich, M.A. Porai-Koshits, Y.A. Buslaer, Coor.
Chem. Rev. 17 (1975) 1.
ꢀ
/
49.1 Hz, JPÃPt
ꢀ
/
[11] A. Appelt, V. Ariaratnam, A.C. Willis, S.B. Wild, Tetrahedron:
Asymmetry 1 (1990) 9.
[12] B.L. Bennett, J. Birnbaum, D.M. Roddick, Polyhedron 14 (1995)
187.
[13] A.D. Burrows, D.M.P. Mingos, S.E. Lawrence, A.J.P. White,
D.J. Williams, J. Chem. Soc., Dalton Trans. (1997) 1295.
[14] (a) A.M.Z. Slawin, M.B. Smith, New J. Chem. 23 (1999) 777;
(b) Y. Matsuura, K. Okude, H. Ichida, T.K. Miyamoto, Y.
Sasaki, Acta Crystallogr. Sect. C: Cryst. Struct. Commun. 48
(1992) 357;
4. Supplementary data
Full crystal structure information has been deposited
with the Cambridge Crystallographic Data Center
(deposition numbers CCDC 178035-CCDC 178038).
Copies of this information are available upon request
from The Director, CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK (fax: ꢁ44-1223-336033; e-mail: depos-
it@ccdc.cam.ac.uk or www: http://www.ccdc.cam.a-
c.uk).
(c) E.K. van den Beuken, A. Meetsma, H. Kooijman, A.L. Spek,
B.L. Feringa, Inorg. Chim. Acta 264 (1997) 171;
(d) T. Suzuki, A. Morikawa, K. Kashiwabara, Bull. Chem. Soc.
Jpn. 69 (1996) 2539.
/
[15] (a) R.H. Summerville, R. Hoffmann, J. Am. Chem. Soc. 98 (1976)
7240;
(b) G. Au´llon, G. Ujaque, A. Lledo´s, S. Alvarez, P. Alemany,
Inorg. Chem. 37 (1998) 804;
Acknowledgements
(c) G. Au´llon, G. Ujaque, A. Lledo´s, S. Alvarez, Chem. Eur. J. 5
(1999) 1391.
[16] (a) C.A. O’Mahoney, I.P. Parkin, D.J. Williams, D.J. Woollins,
Polyhedron 8 (1989) 1979;
We thank the Division of Chemical Sciences, Office of
Basic Energy Sciences, Office of Energy Research, US
Department of Energy (Grant DF-FG02-88ER13880)
for support of this work. A grant from the National
Science Foundation provided a portion of the funds for
the purchase of the NMR (CHE 9221835) equipment.
(b) N.W. Alcock, P. Bergamini, T.J. Kemp, P.G. Pringle, S.
Sostero, O. Traverso, Inorg. Chem. 30 (1991) 1594.
[17] G.R. Clark, A.J. Nielson, C.E.F. Rickard, J. Chem. Soc., Dalton
Trans. (1996) 4265.
[18] B. Twamley, S.T. Haubrich, P.P. Power, Adv. Organomet. Chem.
44 (1999) 1.
[19] Leading references: (a) D.R. Mulford, J.R. Clark, S.W. Schwei-
ger, P.E. Fanwick, I.P. Rothwell, Organometallics 18 (1999) 4448;
(b) M.G. Thorn, P.E. Fanwick, I.P. Rothwell, Organometallics 18
(1999) 4442.
References
[1] Reviews: (a) H.E. Bryndza, W. Tam, Chem. Rev. 88 (1988) 1163;
(b) M.D. Fryzuk, C.D. Montgomery, Coord. Chem. Rev. 95
(1989) 1.
[20] (a) P.P. Power, Comments Inorg. Chem. 8 (1989) 177;
(b) D.E. Wigley, Prog. Inorg. Chem. 42 (1994) 239ꢂ482.
/
[21] (a) G.D. Smith, P.E. Fanwick, I.P. Rothwell, J. Am. Chem. Soc.
[2] For examples see: (a) B.H. Yang, S.L. Buchwald, J. Organomet.
Chem. 576 (1999) 125;
111 (1989) 750;
(b) G.D. Smith, V.M. Visciglio, P.E. Fanwick, I.P. Rothwell,
Organometallics 11 (1992) 1064.
[22] W. Maringgele, A. Meller, Phosphorus Sulfur Silicon Relat. Elem.
(b) J.F. Hartwig, Angew. Chem., Int. Ed. Engl. 37 (1998) 2047
(c) L.A. Villanueva, K.A. Abboud, J.M. Boncella, Organometal-
lics 11 (1992) 2963
90 (1994) 235ꢂ241.
/
(d) C.M. Jensen, W.C. Trogler, J. Am. Chem. Soc. 108 (1986) 723.
[3] (a) P.R. Sharp, J. Chem. Soc., Dalton Trans. (2000) 2647;
(b) P.R. Sharp, Comments Inorg. Chem. 21 (1999) 85.
[4] K. Koo, G.L. Hillhouse, Organometallics 17 (1998) 2924.
[5] (a) S. Kannan, A.J. James, P.R. Sharp, Polyhedron 19 (2000) 155;
(b) H. Shan, A.J. James, P.R. Sharp, Inorg. Chem. 37 (1998) 5727.
[6] J.J. Li, W. Li, A.J. James, T. Holbert, T.P. Sharp, P.R. Sharp,
Inorg. Chem. 38 (1999) 1563.
[23] D.J. Mindiola, G.L. Hillhouse, J. Am. Chem. Soc. 123 (2001)
4623.
[24] A.D. Ryabov, Chem. Rev. 90 (1990) 403.
[25] (a) P.J. Walsh, F.J. Hollander, R.G. Bergman, J. Am. Chem. Soc.
110 (1988) 8729;
(b) S.Y. Lee, R.G. Bergman, J. Am. Chem. Soc. 117 (1995) 5877;
(c) J.L. Bennett, P.T. Wolczanski, J. Am. Chem. Soc. 116 (1994)
2179;
[7] (a) M.S. Balakrishna, V.S. Reddy, S.S. Krishnamurthy, J.F.
Nixon, J.C.T.R. Burckett, Coord. Chem. Rev. 129 (1994) 1;
(b) M. Witt, H.W. Roesky, Chem. Rev. 94 (1994) 1163.
(d) C.P. Schaller, C.C. Cummins, P.T. Wolczanski, J. Am. Chem.
Soc. 118 (1996) 591;
(e) C.P. Schaller, P.T. Wolczanski, Inorg. Chem. 32 (1993) 131.
[26] M.A. Andrews, G.L. Gould, E.J. Vos, Inorg. Chem. 35 (1996)
5740.
[8] G.A. Lawrance, Chem. Rev. 86 (1986) 17ꢂ33.
[9] (a) M.S. Balakrishna, S.S. Krishnamurthy, R. Murugavel, M.
Nethaji, I.I. Mathews, J. Chem. Soc., Dalton Trans. (1993) 477;
/