Reaction of the carbodiphosphorane Ph3P=C=PPh3 with platinum(II) and -(0) compounds: Platinum induced activation of C-H bonds

Article abstract of DOI:10.1021/om0580248

The complex [(cod)PtI₂] (cod = 1,5-cyclooctadiene) reacts with 3 equiv of the hexaphenyl-carbodiphosphorane Ph₃P=C=PPh₃ (1) in THF solution to give the novel Pt(II) complex [(η³-C ₈H₁₁)Pt(C₆H₄PPh₂CPPh ₃)] (2) along with the salt [HC(PPh₃)₂]I. In addition to the coordination of the ylidic carbon atom at the Pt atom, 2 contains two further Pt-C σ bonds originating from H to Pt exchange in the ortho position of one phenyl group of the carbodiphosphorane ligand and in the former cod ligand. The resulting C₈H₁₁ moiety is coordinated to the Pt atom in an η³ manner via a double bond and a σ bond and contains a further uncoordinated double bond. From a 1:1 reaction mixture in toluene/CH₂Cl₂ the majority of the crystals consist of the salt [HC(PPh₃)₂]I·2CH ₂Cl₂ (3) with small amounts of platinum compounds as byproducts. The Pt(0) complex [(PPh₃)₂Pt(CH ₂=CH₂)] does not react with 1 but decomposes at elevated temperatures to give the known dinuclear complex [Pt₂-(PPh ₃)₂(μ-PPh₂] (4). The complexes 2 and 4 and the salt 3 could be characterized by X-ray analyses and the usual spectroscopic methods.

Full text of DOI:10.1021/om0580248

5038
Organometallics 2005, 24, 5038-5043
Reaction of the Carbodiphosphorane Ph3PdCdPPh3 with
Platinum(II) and -(0) Compounds: Platinum Induced
Activation of C-H Bonds
Wolfgang Petz,* Christian Kutschera, and Bernhard Neumu¨ller*
Fachbereich Chemie der Universita¨t Marburg, Hans-Meerwein-Strasse,
35032 Marburg, Germany
Received April 27, 2005
The complex [(cod)PtI2] (cod ) 1,5-cyclooctadiene) reacts with 3 equiv of the hexaphenyl-
carbodiphosphorane Ph3PdCdPPh3 (1) in THF solution to give the novel Pt(II) complex [(η3-
C8H11)Pt(C6H4PPh2CPPh3)] (2) along with the salt [HC(PPh3)2]I. In addition to the
coordination of the ylidic carbon atom at the Pt atom, 2 contains two further Pt-C σ bonds
originating from H to Pt exchange in the ortho position of one phenyl group of the
carbodiphosphorane ligand and in the former cod ligand. The resulting C8H11 moiety is
coordinated to the Pt atom in an η3 manner via a double bond and a σ bond and contains a
further uncoordinated double bond. From a 1:1 reaction mixture in toluene/CH2Cl2 the
majority of the crystals consist of the salt [HC(PPh3)2]I‚2CH2Cl2 (3) with small amounts of
platinum compounds as byproducts. The Pt(0) complex [(PPh3)2Pt(CH2dCH2)] does not react
with 1 but decomposes at elevated temperatures to give the known dinuclear complex [Pt2-
(PPh3)2(µ-PPh2)2] (4). The complexes 2 and 4 and the salt 3 could be characterized by X-ray
analyses and the usual spectroscopic methods.
Chart 1
Introduction
The double ylide hexaphenylcarbodiphosphorane,
Ph3PdCdPPh3 (1), has been known for more than 40
years,1 and the bent structure2 with an approximate sp2
carbon atom and a free pair of electrons predestines this
compound to act as a Lewis base. 1 can also be seen as
a zerovalent carbon atom which is stabilized by two
neutral phosphine ligands, thus attaining eight elec-
trons. Those compounds are of considerable interest as
possible transfer reagents for a single unsubstituted
carbon atom. Earlier reviews concerning the chemistry
of ylides were collected by Schmidbaur3 and Kaska,4 and
parts were referred to in a chapter of a monograph.5
In principle, 1 can act as a donor with one or two pairs
of electrons, involving sp2 (1a) or sp3 (1b) hybridization
of the carbon atom, as depicted in Chart 1. As electron
pair acceptors, main-group or transition-metal Lewis
acids may be operative. In main-group chemistry ad-
ducts of 1 (or 1a) with the atoms or ions S, Se,6 [I+],7 or
[Cl+], respectively, and the electron-deficient compounds
The only proven transition-metal carbonyl complexes in
which 1 acts as a ligand are the nickel complexes
[(CO)3NiC(PPh3)2] and [(CO)2NiC(PPh3)2].9 Other tran-
sition-metal adducts are known with ReO3+ 10 and with
copper compounds;11 several Au complexes have also
been published recently, including the first example of
a complex with 1b bridging an aurophilic Au‚‚‚Au
interaction.12 The nucleophilic attack of 1 at a carbonyl
carbon atom was reported with [Fe(CO)5]13 and [Mn(CO)5-
Br]14 to produce the metal-bonded heterocumulene
ligand CdCdPPh3 with OPPh3 being split off. With the
16-electron heteroallene Lewis acids EdCdE (E ) S,
O) adducts are formed with C-C bond formation15
which could be characterized by X-ray analyses;16 also
8
InMe3 and AlBr3 were established by X-ray analyses.
(8) Petz, W.; Kutschera, C.; Tschan, S.; Weller, F.; Neumu¨ller, B.
Z. Anorg. Allg. Chem. 2003, 629, 1235-1244.
* To whom correspondence should be addressed. E-mail: petz@
staff.uni-marburg.de (W.P.); neumuell@chemie.uni-marburg.de (B.N.).
(1) Ramirez, F.; Desai, N. B.; Hansen, B.; McKelvie, N. J. Am. Chem.
Soc. 1961, 83, 3539-3540.
(9) Petz, W.; Weller, F.; Uddin, J.; Frenking, G. Organometallics
1999, 18, 619-626.
(10) Sundermeyer, J.; Weber, K.; Peters, K.; von Schnering, H. G.
Organometallics 1994, 13, 2560-2562.
(2) Vincent, A. T.; Wheatley, P. J. J. Chem. Soc., Dalton Trans. 1972,
617-622.
(11) Schmidbaur, H.; Zybill, C. E.; Mu¨ller, G.; Kru¨ger, C. Angew.
Chem. 1983, 95, 753-755; Angew. Chem., Int. Ed. Engl. 1983, 22, 729.
(12) Vicente, J.; Singhal, A. R.; Jones, P. G. Organometallics 2002,
21, 5887-5900.
(3) Schmidbaur, H. Angew. Chem. 1983, 95, 980-1000; Angew.
Chem., Int. Ed. Engl. 1983, 22, 907.
(4) (a) Kaska, W. C. Coord. Chem. Rev. 1983, 48, 1-58. (b)
Kolodiazhnyi, O. I. Tetrahedron 1996, 52, 1855-1929.
(5) Johnson, A. W. Ylides and Imines of Phosphorus; Wiley-Inter-
science: New York, Chichester, Brisbane, Toronto, Singapore, 1993.
(6) Schmidbaur, H.; Zybill, C. E.; Neugebauer, D. Angew. Chem.
1982, 94, 321-322; Angew. Chem., Int. Ed. Engl. 1982, 21, 310.
(7) Schmidbaur, H.; Zybill, C.; Neugebauer, D.; Mu¨ller, G. Z.
Naturforsch. 1985, 40b, 1293-1300.
(13) Petz, W.; Weller, F. Z. Naturforsch. 1996, 51b, 1598-1604.
(14) Goldberg, S. Z.; Duessler, E. N.; Raymond, K. Inorg. Chem.
1972, 11, 1397-1401.
(15) Matthews, C. N.; Driscoll, J. S.; Birum, G. H. J. Chem. Soc.,
Chem. Commun. 1966, 736-737.
(16) Petz, W.; Kutschera, C.; Heitbaum, M.; Neumu¨ller, B.; Fren-
king, G.; Tonner, R. Inorg. Chem. 2005, 44, 1263-1274.
10.1021/om0580248 CCC: $30.25 © 2005 American Chemical Society
Publication on Web 09/10/2005

Pt-Induced Activation of C-H Bonds
Organometallics, Vol. 24, No. 21, 2005 5039
Scheme 1
bond has changed into a carbon to platinum σ bond; for
an allyl-like interaction with the platinum atom the
related Pt-C and C-C distances are inconsistent, and
also the electronic counting for a planar 16-electron
Pt(II) complex does not need a further pair of electrons.
Ortho metalation of phenyl groups of 1 was mentioned
earlier with another Pt source,19 but without confirma-
tion by a crystal structure. C-H activation of the cod
ligand coordinated at iridium was described, but the
resulting complexes contain the cyclooctadienyl group
in an η3:η2 coordination mode.20
The H+ abstraction from different sources generates
two types of phosphorus atoms. Thus, in the 31P NMR
spectrum two doublets are observed at 55.7 and 14.9
ppm with the expected 195Pt satellites and 2J(Pt,P)
coupling constants of 55 and 51 Hz, respectively. The
low-field signal presumably belongs to the phosphorus
atom in the P-C-C-Pt-C ring. 2 dissolves readily in
CHCl3 and CH2Cl2, but solutions are not stable and
decomposition occurs more quickly in CHCl3 and more
slowly in CH2Cl2. The 1H NMR spectrum shows two sets
of multiplets; one set between 4.0 and 4.9 ppm can be
assigned to the olefinic protons, whereas the set between
1.2 and 2.7 ppm belongs to the aliphatic ones.
Attempts were also made to reject the cod ligand
during the reaction. However, even in the presence of
excess PPh3 or MeCN only the complex 2 could be
isolated from the THF solution and the former cod
ligand remains strongly bonded as the C8H11 fragment.
The IR spectrum of 2 exhibits two strong bands at
1098 and 1047 cm-1, which can be assigned to the
ν(PCP) vibration, and, relative to the related bands of
1, a shift to lower frequencies has occurred. The majority
of bands, however, belong to the vibrations of the PPh3
group and were not assigned further.
Several runs of the reaction were carried out with
other molar ratios of the components, including a 1:1
molar ratio. The oily material obtained in this case was
dissolved in CH2Cl2. From this solution layered with
n-pentane a few crystals could be isolated after several
weeks. One sort of crystal was identified by X-ray
analysis to be a platinum complex containing the Pt
atom in the formal oxidation number IV with a pincer
ligand derived from double deprotonation of 1, but the
complex could not be characterized sufficiently as yet.
The majority of crystals were found to be the salt [HC-
(PPh3)2]I‚2CH2Cl2 (3).
Among the possible coordination modes of 1, the most
interesting one, however, would be that of an η2
coordination which mimics the well-established bond of
CO2 and CS2 at transition metals. One example of such
a complex has been published earlier, obtained from the
reaction of 1 with the Pt(0) complex [(PPh3)2Pt(CH2d
CH2)], in which the olefin was thought to be replaced
by the P-C double bond to give the complex [(PPh3)2-
Pt(η2-{Ph3PdCdPPh3})].18 In contrast, we found that
1 does not react with the Pt(0) complex. If a mixture of
both components was stirred for several hours at room
temperature in toluene solution, no change of the 31P
NMR signals of the starting materials was observed,
even after prolonged reaction times. The 31P NMR data
Scheme 2
one example with E ) NPh was described.17 Further-
more, some complexes with platinum compounds have
also been mentioned in which either 1 coordinates in
an η2 manner18 or ortho metalation of phenyl groups of
1 was theorized with formation of Pt-C bonds.19 In this
contribution we describe the reaction of 1 with [(cod)-
PtI2] and the crystal structure of the resulting com-
pound. Additionally, we have studied again the reaction
of 1 with [(PPh3)2Pt(CH2dCH2)] in order to prove the
existence of the η2 coordination of 1 described earlier.18
Results and Discussion
We have studied the reaction of 1 with [(cod)PtI2]
under various conditions. If a 3:1 mixture of 1 and the
platinum complex were allowed to react in THF for
several hours, an orange solution along with a white
precipitate was obtained. The precipitate was found to
be the salt [HC(PPh3)2]I, which is only slightly soluble
in THF. From the solution orange-yellow crystals of the
carbodiphosphorane complex [Pt(η3-C8H11)(C6H4PPh2-
CPPh3)] (2) could be isolated in high yield, as shown in
Scheme 1. The new complex 2 exhibits an unusual
bonding situation. In addition to the coordination of the
double ylide at the metal atom via the ylidic carbon
atom, a Pt-C σ bond to an ortho carbon atom of a
phenyl group has formed and, surprisingly, a second
Pt-C σ bond has been established to a carbon atom of
the former cod ligand to give the fragment C8H11. The
platinum-induced proton abstraction produces 2 mol of
HI, which is trapped as the salt [HC(PPh3)2]I. The
reaction of [(cod)PtCl2] with 1 under the same conditions
leads also to the formation of 2 with similar yields, and
the HCl was trapped as the corresponding salt
[HC(PPh3)2]Cl.
The cod deprotonation to produce the 2,5-cycloocta-
dienyl ligand takes place in the position R to one double
bond followed by formation of a new uncoordinated
double bond via a 1,2-shift, as depicted in Scheme 2.
One of the former π-bonded carbon atoms of one double
(17) (a) Ramirez, F.; Pilot, J. F.; Desai, N. B.; Smith, C. B.; Hansen,
B.; McKelvie, N. J. Am. Chem. Soc. 1967, 89, 6273-6276. (b) Ross, F.
K.; Hamilton, W. C.; Ramirez, F. Acta Crystallogr., Sect. B 1971, 27,
2331-2334.
(18) Kaska, W. C.; Mitchel, D. K.; Reichelderfer, R. F. J. Organomet.
Chem. 1973, 47, 391-402.
(19) Baldwin, J. C.; Kaska, W. C. Inorg. Chem. 1979, 18, 686-691.
(20) (a) Martin, M.; Sola, E.; Torres, O.; Plou, P.; Oro, L. A.
Organometallics 2003, 22, 5406-5417 and literature therein for
various coordination modes of cod or cyclooctadienyl.

5040 Organometallics, Vol. 24, No. 21, 2005
Petz et al.
Scheme 3
(in THF) given in this paper as a proof of η2 coordination
were found to be identical with the chemical shifts and
coupling constants of the hydrolysis product Ph2P(O)-
CHPPh3 (doublets at 24.6 and 20.9 ppm; J(P,P) ) 19.1
Hz) and of OPPh3 (23.2 ppm). However, if the reaction
was carried out at elevated temperature, the solution
turned red and we isolated a deep red crystalline
compound, which was identified as the dinuclear com-
pound [Ph3PPt(µ-PPh2)2PtPPh3] (4), and 1 was not
consumed (Scheme 3). The complex 4 was prepared and
characterized earlier and obtained upon refluxing [Pt-
(PPh3)4] in benzene.21 It is obvious that at elevated
temperature loss of the olefin generates the carbene-
like [Pt(PPh3)2], which is also formed from [Pt(PPh3)4],
finally leading to the same thermal decomposition
product without participation of 1.
Figure 1. Projection view of [(η3-C8H11)Pt(C6H4PPh2-
CPPh3)] (2) with the labeling scheme (40% ellipsoids). The
hydrogen atoms and the disordered THF molecule have
been omitted for clarity.
group is appreciably longer (2.09 Å) than in related
compounds containing a similar ortho carbon bond,23
whereas the distances to the three C8H11 carbon atoms
are 0.05-0.06 Å longer (2.14 Å) with nearly identical
Pt-C distances (σ and π). In the former η4-cod ligand a
deprotonation in the position R to one double bond
occurred, followed by a 1,2-shift to give the η3-C8H11
ligand, and the new double bond established between
C(44) and C(45) is not involved in the coordination, as
shown by the short C-C bond length of 1.29 Å. Thus,
an alternative allylic bond can be excluded and the Pt
atom attains 16 electrons, which is typical for a square-
planar coordination of Pt(II) compounds. The new C8H11
(cyclooctadienyl) moiety is now coordinating at the Pt
atom via a π bond and a σ bond, and according to the
asymmetric connections this σ-bonded carbon atom is
chiral. Thus, the unit cell contains a pair of enantiomers.
The P-C bond distances to the ylidic carbon atom C(1)
are slightly different (1.69 and 1.72 Å), and the shorter
one belongs to that of the “free” (dangling) PPh3 group.
The P-C-P bond angle is 121.3°, a value which is
among the lowest recorded for addition compounds of
the type E-C(PPh3)2.8 The large P-C-P bond angles
of carbodiphosphorane adducts (125-136°) are probably
due to a parallel arrangement of two phenyl rings found
in all these compounds, which have their ipso C atoms
within the ECP2 plane. This arrangement is probably
necessary for an optimal interaction of the occupied p
orbital at C(1) with the P-Cipso σ* orbitals derived from
the other two P-Cphenyl bonds out of the plane (or their
mixtures with d orbitals); the repulsive interaction of
these parallel phenyl groups may be responsible for the
large P-C-P angles. In 2, however, upon Pt-Cphenyl
bond formation this ortho-metalated phenyl ring is now
located within the ECP2 plane, the repulsive interaction
is lost, and the P-C-P angle approaches 120° due to a
normal sp2 carbon atom.
Crystal Structures
General Remarks. To get more detail on the proper-
ties of the compounds, the structures of the complexes
2 and 4 and the salt 3 have been determined by single-
crystal X-ray diffraction studies. Suitable yellow crystals
of 2 (with 1.5 molecules of THF) were obtained by
layering a THF solution with n-pentane. 3 was grown
from CH2Cl2 solutions. Crystals of the dinuclear complex
4 contain one disordered toluene molecule; the product
reported earlier was described with one molecule of
benzene. ORTEP views of the molecules 2 and 3 are
depicted in Figures 1 and 2; the structure of the
previously described platinum complex 4 is not depicted.
Details of the structure determinations are collected in
Table 1; selected bond lengths and angles are sum-
marized in Tables 2-4.
Crystal Structure of 2. The central part of the
molecule is the five-membered planar heterocycle con-
taining the atoms Pt and P(2), the sp2 carbon atom C(1)
(∑ ) 360°) of the carbodiphosphorane ligand, and two
sp2 phenyl carbon atoms. The planarity may be indica-
tive of some electron delocalization within the ring. The
ligand arrangement around the platinum atom is es-
sentially planar and is composed of three carbon atoms
and the center of the cod double bond, as shown in
Figure 1. The platinum atom is in the formal oxidation
state II. The Pt-C bond length to the ylide carbon atom
is found at the lower limit of a single bond (2.07 Å),21,22
and the bond to the ortho carbon atom of the phenyl
Crystal Structure of 3. The salt 3 crystallizes as
an ion pair with two molecules of CH2Cl2, and this
(21) Taylor, N. J.; Chieh, P. C.; Carty, A. J. J. Chem. Soc., Chem.
Commun. 1975, 448-449.
(22) Jones, N. D.; Lin, G.; Gossage, R. A.; McDonald, R.; Cavell, R.
G. Organometallics 2003, 22, 2832-2841.
(23) Anderson, G. K. In Comprehensive Organometallic Chemistry
II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press:
Oxford, U.K., 1995; Vol. 9, pp 507-518 and references therein.

Pt-Induced Activation of C-H Bonds
Organometallics, Vol. 24, No. 21, 2005 5041
Figure 2. Projection view of the centrosymmetric dimer [HC(PPh3)2]I‚2CH2Cl2 (3) with the labeling scheme (40% ellipsoids),
indicating the weak H bridges.
Table 1. Summary of the X-ray Data for Complexes 2 and 4 and the Salt 3
2
3
4
formula
mol wt
a/Å
C
51H52O1.5P2Pt
C39H35Cl4IP2
1668.75
C67H58P4Pt2
1377.27
15.868(1)
16.638(1)
21.362(2)
90
946.00
9.627(1)
11.182(1)
13.486(1)
14.818(1)
102.85(1)
104.65(1)
112.14(1)
0.33 × 0.15 × 0.1
1872.4(3)
2
b/Å
12.184(1)
18.230(1)
83.50(1)
c/Å
R/deg
â/deg
87.75(1)
77.00(1)
0.24 × 0.14 × 0.07
2069.9(3)
2
1.518
triclinic
97.24(1)
90
γ/deg
cryst size/mm
0.11 × 0.07 × 0.04
5594.9(7)
4
V/Å3
Z
dcalcd (g/cm3)
cryst syst
space group
diffractometer
radiation
temp (K)
1.48
triclinic
1.635
monoclinic
P21/n (No. 14)
IPDS II (Stoe)
Mo KR
P1h (No. 2)
IPDS II (Stoe)
Mo KR
P1h (No. 2)
IPDS I (Stoe)
Mo KR
193
193
193
µ (cm-1
)
35.1
12.5
51.5
2θmax/deg
52.62
51.90
52.53
index ranges
-11 e h e 11
-15 e k e 14
-22 e l e 22
24 971
-13 e h e 13
-16 e k e 16
-18 e l e 18
18 466
-19 e h e 19
-19 e k e 20
-26 e l e 26
80 189
no. of rflns collected
no. of indep rflns (Rint
no. of obsd rflns with Fo > 4σ(Fo)
no. of params
abs cor
structure soln
)
8298 (0.0366)
7310
529
numerical
Patterson method,
SHELXTL-Plus 27
SHELXL-97 30
0.03
6783 (0.044)
5143
420
numerical
direct methods,
SIR-92 29
SHELXL-97 30
0.0321
11 255 (0.1402)
5912
618
numerical
direct methods,
SHELXS-97 28
SHELXL-97 30
0.041
refinement against F2
R1
wR2 (all data)
max electron density
left/(e/10-6 pm3)
0.074
1.15
0.0781
0.75
0.0759
1.1
composition forms a centrosymmetric dimer connected
by four very weak H‚‚‚I bridges, as shown in Figure 2.
The sequence P(1)-C(19)H(1)-P(2) is planar. Four
nearer contacts exist from the iodine ion to H(1)
(C-H‚‚‚‚I ) 4.066(4) Å), to a proton of both CH2Cl2
molecules (C-H‚‚‚‚I ) 3.787(5), 3.944(4) Å), and to a
meta proton of a phenyl group (C-H‚‚‚‚I ) 3.892(4) Å).
The latter pair of C-H‚‚‚‚I interactions leads to the
dimeric unit; all values given are C‚‚‚‚I contacts. The
other parameters of the cation are close to those
reported earlier.8
Crystal Structure of 4. The crystallographic data
of 4 do not differ markedly from those reported earlier.21
However, in 4 the more precise low-temperature struc-
ture exhibits slightly shorter Pt-P and Pt-Pt bond
lengths within the Pt2P2 ring system, and both terminal
Pt-P distances are identical. The bridging phosphorus
atoms are in an approximately tetrahedral environment
with acute Pt-P-Pt angles of 69° and a less acute
C-P-C angle of 103°. The different Pt-P-C angles in
pairs indicate a slight twist of the carbon atoms out of
the local mirror plane, which can be drawn through the

5042 Organometallics, Vol. 24, No. 21, 2005
Petz et al.
Table 2. Selected Bond Lengths and Angles in
Table 4. Selected Bond Lengths and Angles in
[Pt(η3-C8H11)(C6H4PPh2CPPh3)] (2)
[Pt2(PPh3)2(µ-PPh2)2] (4)
Distances (Å)
Distances (Å)
Pt(1)-C(1)
Pt(1)-C(38)
Pt(1)-C(42)
P(1)-C(2)
P(1)-C(14)
P(2)-C(20)
P(2)-C(32)
C(26)-C(31)
C(28)-C(29)
C(30)-C(31)
C(38)-C(45)
C(40)-C(41)
C(42)-C(43)
C(44)-C(45)
2.072(3)
2.139(4)
2.143(4)
1.830(4)
1.823(4)
1.825(4)
1.827(4)
1.408(6)
1.371(7)
1.413(6)
1.478(7)
1.522(7)
1.490(7)
1.288(8)
Pt(1)-C(31)
Pt(1)-C(41)
P(1)-C(1)
2.086(4)
2.148(4)
1.694(4)
1.818(4)
1.716(4)
1.794(4)
1.379(6)
1.390(6)
1.377(6)
1.530(6)
1.572(8)
1.393(7)
1.460(8)
Pt(1)-Pt(2)
Pt(1)-P(2)
Pt(2)-P(1)
Pt(2)-P(4)
P(1)-C(7)
P(2)-C(19)
P(3)-C(31)
P(4)-C(43)
P(4)-C(55)
2.5946(5)
2.305(2)
2.307(2)
2.230(2)
1.82(1)
1.807(9)
1.804(9)
1.826(8)
1.824(9)
Pt(1)-P(1)
Pt(1)-P(3)
Pt(2)-P(2)
P(1)-C(1)
P(2)-C(13)
P(3)-C(25)
P(3)-C(37)
P(4)-C(49)
2.288(2)
2.230(2)
2.302(2)
1.823(9)
1.823(9)
1.805(9)
1.832(9)
1.843(7)
P(1)-C(8)
P(2)-C(1)
P(2)-C(26)
C(26)-C(27)
C(27)-C(28)
C(29)-C(30)
C(38)-C(39)
C(39)-C(40)
C(41)-C(42)
C(43)-C(44)
Angles (deg)
Pt(2)-Pt(1)-P(1)
Pt(2)-Pt(1)-P(3)
P(1)-Pt(1)-P(3)
Pt(1)-Pt(2)-P(1)
Pt(1)-Pt(2)-P(4)
P(1)-Pt(2)-P(4)
Pt(1)-P(1)-Pt(2)
Pt(1)-P(1)-C(7)
Pt(2)-P(1)-C(7)
Pt(1)-P(2)-Pt(2)
55.96(5) Pt(2)-Pt(1)-P(2)
175.47(6) P(1)-Pt(1)-P(2)
55.66(5)
111.62(7)
122.93(7)
55.78(5)
111.04(7)
122.77(7)
117.8(3)
123.6(3)
102.9(4)
117.9(3)
123.7(3)
125.28
P(2)-Pt(1)-P(3)
55.27(5) Pt(1)-Pt(2)-P(2)
177.48(6) P(1)-Pt(2)-P(2)
126.16(7) P(2)-Pt(2)-P(4)
68.77(6) Pt(1)-P(1)-C(1)
Angles (deg)
C(1)-Pt(1)-C(31)
C(1)-Pt(1)-C(41)
C(31)-Pt(1)-C(38)
C(31)-Pt(1)-C(42)
C(38)-Pt(1)-C(42)
C(1)-P(1)-C(2)
86.0(1) C(1)-Pt(1)-C(38)
163.5(2) C(1)-Pt(1)-C(42)
175.9(1) C(31)-Pt(1)-C(41)
90.9(2) C(38)-Pt(1)-C(41)
86.7(2) C(41)-Pt(1)-C(42)
114.8(2) C(1)-P(1)-C(8)
116.2(2) C(2)-P(1)-C(8)
102.1(2) C(8)-P(1)-C(14)
117.4(2) C(1)-P(2)-C(26)
116.4(2) C(20)-P(2)-C(26)
105.3(2) C(26)-P(2)-C(23)
124.1(2) Pt(1)-C(1)-P(2)
121.3(2) P(2)-C(26)-C(27)
97.5(1)
158.6(2)
95.2(2)
80.8(2)
37.9(2)
111.9(2)
107.5(2)
103.3(2)
104.8(2)
105.2(2)
106.6(2)
114.6(2)
121.1(3)
122.7(3)
119.7(3)
Pt(2)-P(1)-C(1)
C(1)-P(1)-C(7)
68.56(6) Pt(1)-P(2)-C(13)
Pt(1)-P(2)-C(19) 123.4(3)
Pt(2)-P(2)-C(19) 118.0(3)
Pt(2)-P(2)-C(13)
C(13)-P(2)-C(19) 103.5(4)
C(1)-P(1)-C(14)
C(2)-P(1)-C(14)
C(1)-P(2)-C(20)
C(1)-P(2)-C(32)
C(20)-P(2)-C(23)
Pt(1)-C(1)-P(1)
P(1)-C(1)-P(2)
and the crystallographic characterization of some crys-
tals of complexes with symmetric tridentate ligands
derived from 1 with participation of the solvent CH2Cl2
show that under special conditions also a double phenyl
ring C-H activation with platinum can occur, and our
efforts are now concentrated on the variation of the
reaction conditions in such a way that those compounds
can be reproduced and increased in yield for further
characterization. The carbodiphosphorane 1 is a poten-
tial four-electron-donor ligand (1b), and if one pair of
electrons is donating at a Lewis acid in adducts such
as ErC(PPh3)2, an additional pair is possibly available
for further reactions. Thus, exploring its chemistry is a
challenge for preparative and theoretical chemists. The
insertion of a metal atom into the ortho CH bond of 1
could as yet not be observed with other transition or
main group metals or elements.24 The role of platinum
in the activation of C-H bonds23,25 is very important
for catalytic processes, and further studies on this
subject are in progress.
P(2)-C(26)-C(31)
114.1(3) C(27)-C(26)-C(31) 124.8(4)
C(26)-C(27)-C(28) 119.0(4) C(27)-C(28)-C(29) 118.8(4)
C(28)-C(29)-C(30) 121.2(4) C(29)-C(30)-C(31) 123.0(4)
Pt(1)-C(31)-C(26)
C(26)-C(31)-C(30) 113.1(3) Pt(1)-C(38)-C(39)
Pt(1)-C(38)-C(45)
120.1(3) Pt(1)-C(31)-C(30)
126.8(3)
106.1(3)
112.3(3) C(39)-C(38)-C(45) 110.5(3)
C(38)-C(39)-C(40) 110.1(4) C(39)-C(40)-C(41) 111.3(4)
Pt(1)-C(41)-C(40)
C(40)-C(41)-C(42) 119.3(4) Pt(1)-C(42)-C(41)
Pt(1)-C(42)-C(43)
112.2(4) Pt(1)-C(41)-C(42)
70.9(2)
71.3(2)
119.4(3) C(41)-C(42)-C(43) 127.3(4)
C(42)-C(43)-C(44) 120.1(5) C(43)-C(44)-C(45) 128.2(5)
C(38)-C(45)-C(44) 129.3(5)
Table 3. Selected Bond Lengths and Angles in
[HC(PPh3)2]I‚2CH2Cl2 (3)
Distances (Å)
P(1)-C(1)
1.803(3)
1.805(3)
1.705(3)
1.820(3)
0.90(4)
P(1)-C(7)
1.813(3)
1.699(3)
1.806(3)
1.810(3)
4.066(4)
P(1)-C(13)
P(2)-C(19)
P(2)-C(26)
C(19)-H(1)
P(1)-C(19)
P(2)-C(20)
P(2)-C(32)
C(19)‚‚‚‚‚‚I(1)
Another question deals with the properties of the P-C
“double bond” in 1, concerning its ability to form an
interesting η2 coordination at a transition metal; how-
ever, as yet, we were not able to confirm such a bonding
mode.
Angles (deg)
C(1)-P(1)-C(7)
C(1)-P(1)-C(19)
C(7)-P(1)-C(19)
C(19)-P(2)-C(20)
C(19)-P(2)-C(32)
C(20)-P(2)-C(32)
P(1)-C(19)-P(2)
P(2)-C(19)-H(1)
108.4(1)
C(1)-P(1)-C(7)
106.6(1)
104.4(2)
115.1(1)
115.9(1)
107.8(2)
104.3(1)
115(2)
111.2(2)
110.8(1)
113.8(1)
107.8(2)
106.2(1)
129.1(2)
116(2)
C(1)-P(1)-C(13)
C(13)-P(1)-C(19)
C(19)-P(2)-C(26)
C(20)-P(2)-C(26)
C(26)-P(2)-C(32)
P(1)-C(19)-H(1)
Experimental Section
General Considerations. All operations were carried out
under an argon atmosphere in dried and degassed solvents
using Schlenk techniques. IR spectra (in Nujol) were run on a
Nicolet 510 spectrometer. 13C NMR and 1H NMR spectra were
recorded on a Bruker AC 300 instrument using SiMe4 (δ 0.00
ppm) as the external standard. 31P NMR spectra were run on
a Bruker ARX 200 spectrometer and referenced to external
bridging phosphorus atoms, and the middle of the
Pt-Pt bond.
Conclusion
(24) After preparation of this paper a Rh complex with two ortho-
metalated phenyl groups was reported: Kubo, K.; Jones, N. D.;
Ferguson, M. J.; McDonald, R.; Cavell, R. G. J. Am. Chem. Soc. 2005,
127, 5314-5315.
(25) (a) Falvello, L. R.; Fernandez, S.; Larraz, C.; Llusar, R.;
Navarro, R.; Urriolabeitia, E. P. Organometallics 2001, 20, 1424-1436.
(b) Zucca, A.; Doppiu, A.; Cinellu, M. A.; Stoccoro, S.; Minghetti, G.;
Manassero, M. Organometallics 2002, 21, 783-785. (c) McGuinness,
D. S.; Cavell, K. J.; Yates, B. F. Chem. Commun. 2001, 355-356. d)
Stepien, M.; Latos-Grazynski, L. Chem. Eur. J. 2001, 7, 5113-5117.
From the reaction of 1 with [(cod)PtI2] or [(cod)PtCl2]
at present we could only isolate and characterize the
complex 2 sufficiently, and to our knowledge this is the
first structural proof of a cod C-H activation with
platinum. The unusual deprotonation of a phenyl ring
and of the cod ligand during the reaction is as yet not
understood. Hints from 31P NMR data and the isolation

Pt-Induced Activation of C-H Bonds
Organometallics, Vol. 24, No. 21, 2005 5043
H3PO4. Elemental analyses were performed by the analytical
service of the Fachbereich Chemie der Universita¨t Marburg
(Marburg, Germany). [(cod)PtI2] was prepared from K2[PtCl4]
and cod to give [(cod)PtCl2], followed by halogen exchange with
NaI according to a literature procedure,26 and 1 was obtained
by a modified procedure, as described earlier.15 Commercially
available [(PPh3)2Pt(CH2dCH2)] was used without further
purification.
the THF solution were identical with the signals of the complex
2, and the precipitate was identified as the salt [HC(PPh3)2]-
Cl. From the THF solution 2 was precipitated with n-pentane
as described above. Yield: 0.42 g (85%). Yield of [HC(PPh3)2]-
Cl: 0.62 g, 1.08 mmol (92%). 31P NMR (CH2Cl2): 20.03 ppm.
Reaction of 1 with [(cod)PtI2] in the Presence of
Donor Ligands. The reaction described for the synthesis of
2 was also carried out in the presence of excess PPh3 and
acetonitrile, respectively. However, in all cases only the
complex 2 could be identified by 31P NMR spectroscopy and
no hints of splitting off cod and a symmetric HI abstraction
were detected.
Reaction of 1 with [(cod)PtI2] (1:1 Molar Ratio). The
above procedure was carried out with a 1:1 molar ratio of the
starting materials in toluene. After the mixture was stirred
for several days, the solvent was evaporated, the oily residue
extracted with CH2Cl2, and the solution filtered. The clear
yellow solution was layered with pentane. After some weeks,
a few crystals were obtained along with an amorphous powder.
Some pale yellow and orange-brown crystals were identified
by X-ray analyses as platinum complexes, whereas the major-
ity of crystals were found to be the salt [HC(PPh3)2]I‚2CH2Cl2
(3).
Reaction of 1 with [(PPh3)2Pt(CH2dCH2)]. To a solution
of 0.58 g (0.78 mmol) of [(PPh3)2Pt(CH2dCH2)] in about 30 mL
of toluene was added an excess of 1 (1.11 g, 2.30 mmol), and
the mixture was stirred for 24 h at room temperature. After
this time the 31P NMR spectrum of the solution showed only
the signals of the starting materials. Then, the mixture was
heated under reflux for 1 h, during which time the solution
turned dark red. After the solution was cooled, red crystals
separated (0.30 g; 60% yield), which were identified as the
binuclear complex [Pt2(PPh3)2(µ-PPh2)2] (4) described earlier;21
the ylide 1 was recovered unchanged.
Preparation of [(η3-C8H11)Pt(C6H4PPh2CPPh3)] (2). To
a solution of 1.15 g (2.15 mmol) of 1 in about 30 mL of THF at
room temperature was added 0.40 g (0.72 mmol) of [I2Pt(cod)],
and the mixture was stirred magnetically for 2 h. A white
precipitate had formed along with an intense orange-yellow
solution. The precipitate was filtered and identified as the salt
[HC(PPh3)2]I. From the clear solution 2 was precipitated with
n-pentane as a pale yellow powder, which was filtered, washed
with n-pentane, and dried under vacuum for 2 h. Yield: 0.60
1
g (90%). H NMR (CDCl3): 1.20, 1.67 (m’s, 5 H), 2.60 (m’s, 2
H), 4.0-4.9 (m’s, 4 H), all C8H11; 6.7-to 7.5 (m’s, Ph, C6H4).
According to the low stability of 2 in CDCl3 solution, the signals
of the C8H11 ligand in the 13C NMR spectrum could not be
assigned. 31P NMR (CDCl3): 55.7 (P(2), d, 2J(P,P) ) 59.8;
2
2
2J(P,Pt) ) 54.7 Hz), 14.9 (P(1), d, J(P,P) ) 59.8; J(P,Pt) )
50.9 Hz). IR (Nujol mull): 1481 m, 1437 s, 1310 w, 1098 vs,
1074 vs, 1026 w, 999 w, 910 w, 810 vs, 743 s, 725 m, 710 s,
694 s, 529 m, 515 m, 498 s, 478 w, 403 m cm-1. Anal. Calcd
for C45H40P2Pt: C, 64.51; H, 4.81. Found: C, 63.81; H, 4.84.
Data for [HC(PPh3)2]I are as follows. 1H NMR (CD2Cl2): 1.78
(CH, t, 2J(HP) ) 5.26 Hz), 7.46-7.56 (m, Ph). 31P NMR (CH2-
Cl2): 20.03 (s). IR (Nujol mull): 1586 w, 1480 m, 1437 s, 1312
w, 1231 s, 1182 m, 1163 w, 1119 m, 1100 s, 1073 w, 1030 w,
1011 m, 990 s, 801 w, 754 m, 747 m, 712 s, 691 s, 671 w, 558
s, 548 s, 517 m, 505 m, 492 m, 482 m, 459 w cm-1
.
Reaction of 1 with [(cod)PtCl2]. To a solution of 0.944 g
(1.76 mmol) of 1 in about 20 mL of THF at room temperature
was added 0.219 g (0.59 mmol) of [(cod)PtCl2], and the mixture
was worked up as described above. The 31P NMR signals of
Acknowledgment. We are grateful to the Deutsche
Forschungsgemeinschaft (DFG) for financial support.
We also thank the Max-Planck-Society, Munich, Ger-
many, for supporting this work.
(26) Clark, C.; Manzer, L. E. J. Organomet. Chem. 1973, 59, 411-
428.
(27) Sheldrick, G. M. SHELXTL-Plus, Release 4.0 for R3 Crystal-
lographic Research Systems; Siemens Analytical-X-ray Instruments
Inc., Madison, WI, 1989.
(28) Sheldrick, G. M. SHELXS-97; University of Go¨ttingen, Go¨ttin-
gen, Germany, 1997.
Supporting Information Available: Tables of atomic
positions, equivalent isotropical thermal parameters, and
anisotropic thermal displacement coefficients. This material
is available free of charge via the Internet at http://pubs.acs.org.
(29) Altomare, A.; Cascarano, G.; Giacovazzo. C.; Guagliardi, A,:
Burla, M. C.; Polidori, G.; Camalli, M. SIR-92; University of Bari,
Perugia, Rome, 1992.
(30) Sheldrick, G. M. SHELXL-97; University of Go¨ttingen, Go¨ttin-
gen, Germany, 1997.
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