Alkyl and aryl complexes of platinum(II) and palladium(II) containing the tri(1-cyclohepta-2,4,6-trienyl)phosphane ligand. Intramolecular dynamics and signs of coupling constants

Article abstract of DOI:10.1016/S0020-1693(03)00129-4

Tri(1-cyclohepta-2,4,6-trienyl)phosphane, P(C₇H₇)₃ ([P] when coordinated to the metal centre), behaves as a bidentate chelating ligand in platinum(II) and palladium(II) complexes, [P]MR₂ [M=Pt, R=Me (3a), Et (3b), Pr (3c), Bu (3d), CH₂Ph (3e), Ph (3f), C₆H₄-4-F (3g), C₆F₅ (3h), Fc (3i); M=Pd, R=Me (4a), C₆F₅ (4h)], which were synthesized by the reaction of [P]MCl₂ with either LiR or RMgBr. The molecular structure of 3g was determined by X-ray analysis, confirming the Pt-P bond and the η²-coordination of one of the C₇H₇ rings by its central C=C bond. In solution at room temperature, all complexes are fluxional with respect to the NMR time scale, due to intramolecular exchange of the C₇H₇ rings in η²-C=C coordination to the metal centre. The products were characterised by ¹H, ¹³C, ³¹P and ¹⁹⁵Pt NMR spectroscopy, and signs of various coupling constants were determined by application of appropriate 1D spin tickling experiments and 2D heteronuclear shift correlations.

Full text of DOI:10.1016/S0020-1693(03)00129-4

Inorganica Chimica Acta 352 (2003) 51ꢁ60
/
www.elsevier.com/locate/ica
Alkyl and aryl complexes of platinum(II) and palladium(II)
containing the tri(1-cyclohepta-2,4,6-trienyl)phosphane ligand.
Intramolecular dynamics and signs of coupling constants
Max Herberhold *, Thomas Schmalz, Wolfgang Milius, Bernd Wrackmeyer *
Laboratorium fur Anorganische Chemie, Universitat Bayreuth, D-95440 Bayreuth, Germany
¨ ¨
Received 17 May 2002; accepted 28 August 2002
Dedicated to Prof. Martin A. Bennett
Abstract
Tri(1-cyclohepta-2,4,6-trienyl)phosphane, P(C7H7)3 ([P] when coordinated to the metal centre), behaves as a bidentate chelating
ligand in platinum(II) and palladium(II) complexes, [P]MR2 [MꢀPt, RꢀMe (3a), Et (3b), Pr (3c), Bu (3d), CH2Ph (3e), Ph (3f),
C6H4ꢁ4-F (3g), C6F5 (3h), Fc (3i); MꢀPd, RꢀMe (4a), C6F5 (4h)], which were synthesized by the reaction of [P]MCl2 with either
LiR or RMgBr. The molecular structure of 3g was determined by X-ray analysis, confirming the Ptꢀ
P bond and the h2-
coordination of one of the C7H7 rings by its central CꢁC bond. In solution at room temperature, all complexes are fluxional with
C coordination to the metal centre. The
/
/
/
/
/
/
/
respect to the NMR time scale, due to intramolecular exchange of the C7H7 rings in h2-Cꢁ
/
products were characterised by 1H, 13C, 31P and 195Pt NMR spectroscopy, and signs of various coupling constants were determined
by application of appropriate 1D spin tickling experiments and 2D heteronuclear shift correlations.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Platinum; Palladium; Phosphanes; NMR; Coupling signs; X-ray
1. Introduction
aryl groups are rare [3,4]. Such complexes may be model
compounds with respect to catalytic processes, in which
an olefin becomes coordinated to the metal centre,
reacts and is replaced by another olefin. We have shown
that tri(1-cyclohepta-2,4,6-trienyl)phosphane, P(C7H7)3
[5] (or [P] when coordinated to a metal), can act as a
bidentate ligand in complexes of Pt(II) and Pd(II)
Numerous bis(phosphane)platinum(II) and palladiu-
m(II) complexes bearing either alkyl or aryl groups in
cis or trans positions are known [1]. Similarly, various
(cod)Pt and (cod)Pd complexes (codꢀcycloocta-1,5-
/
diene) have been prepared [2]. However, complexes in
which a phosphane and an h2-coordinated olefin
simultaneously act as ligands in addition to alkyl and
through Pꢀ
central CꢁC bond of one of the C7H7 rings [6ꢁ
particular the chlorides, [P]MCl2 with MꢀPt (1) and Pd
/
M and (h2-Cꢁ
/
C)ꢀ
/
M coordination of the
/
/11]. In
/
(2) [6], have served as useful starting materials in this
chemistry. Recently, we have studied complexes of the
* Corresponding author. Tel.: ꢂ
2157.
E-mail
Herberhold), b.wrack@uni-bayreuth.de (B. Wrackmeyer).
/
49-921-55 2540; fax: ꢂ
/
49-921-55
type [P]Pt(Cꢂ
/
Cꢀ
/
R)2 by multinuclear magnetic reso-
nance (1H, 13C, 31P, 195Pt NMR) in order to explore
the mutual influence of alkynyl groups upon the
addresses:
max.herberhold@uni-bayreuth.de (M.
0020-1693/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0020-1693(03)00129-4

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M. Herberhold et al. / Inorganica Chimica Acta 352 (2003) 51ꢁ60
/
mediate with regular three-coordinate M the two
organyl groups at M would become identical. Similarly,
there is no evidence for an associative mechanism
involving a long-lived intermediate containing the metal
in square-pyramidal surroundings. Such an intermediate
with five-coordinate M should have the M at some stage
in trigonal-bipyramidal surroundings which, again,
would make the organyl groups indistinguishable.
Therefore, it is suggested that the C7H7 ring exchange
proceeds via a transition state, in which the outgoing
ring is immediately replaced by an incoming ring. This
mechanism appears to be general for all compounds of
the type [P]M(L)(L?) studied, as has been found
Scheme 1.
previously [6ꢁ11]. Examples of square planar Rh(I),
/
Pd(II) and Pt(II) complexes with other ligands have
been reported with similar dynamic properties [13,14].
respective functions in trans positions [11]. The present
study focuses on the corresponding influence exerted by
alkyl and aryl groups in [P]MR2 complexes (see Scheme
1).
1
In Fig. 1A, the H NMR spectrum of [P]PtMe2 3c is
shown as a typical example illustrating the dynamic
behaviour (DG*(260 K)ꢀ
/
489
2 kJ molꢃ1). The rate of
this dynamic process is dependent on the metal (Pt
/
complexes are less dynamic than Pd complexes) and on
1
the nature of the organyl groups. Fig. 2 shows the H
2. Results and discussion
and 13C NMR spectra of [P]Pt(C6F5)2 3c, where a rigid
structure, with respect to the NMR time scale, appears
to be present already at room temperature (in contrast
to the analogous Pd complex 4h).
2.1. Synthesis
As shown in Scheme 1, the platinum and palladium
complexes 3 and 4 bearing various alkyl or aryl groups
at the metal can be prepared by treatment of the
chloride 1 or 2 with the respective organolithium or
2.2.2. Chemical shifts and coupling constants
The chemical shifts d1H, d13C, and d195Pt are in the
expected range. Interestingly, the differences in the d31P
values between Pt and Pd complexes do not follow
expectations. In the cases of the dimethyl complexes 3a/
4a, the 31P nucleus in 4a is better shielded than in 3a (in
most Pt(II) and Pd(II) phosphane complexes the reverse
situation is typically observed [15]). In the di(penta-
fluorophenyl) complexes 3h/4h, the d31P values are very
similar, although in this case the 31P nuclear shielding in
3h is slightly increased relative to 4h. The largest value
for the coupling constant 1J(195Pt,31P) is measured in 3h,
in agreement with the polarizing ability of the electro-
Grignard reagent. They are yellow (3aꢁg), bright-brown
/
(4a), colourless (3h, 4h) or red solids (3i) which are
moderately air-stable and can be stored for prolonged
time without decomposition under argon atmosphere.
Although numerous attempts were made to obtain
single crystals, the compounds were always isolated as
powders or microcrystalline materials, except of 3g, of
which single crystals suitable for X-ray structural
analysis could be obtained (vide infra).
2.2. NMR spectroscopic measurements
negative C6F5 group. It is remarkable that the magni-
tude of J(195Pt,31P)ꢀ
significantly larger than for the complexes with phenyl
or alkyl substituents.
The 13C, 31P and 195Pt NMR data are given in the
1
/
2223 Hz in 3e (RꢀCH2Ph) is
/
1
Tables 1 and 2, and H NMR data are listed in the
Section 4 (except of 3h and 4h in Table 2). The data
confirm the proposed structures of 3 and 4 in solution,
and they show that all complexes are fluxional with
2.2.3. Signs of coupling constants
In the platinum(II) complexes, the presence of 1H,
respect to h2-coordination of the central Cꢁ
/C bond of
13C, 31P and 195Pt nuclei gives rise to numerous spinꢁ
spin coupling interactions, of which the signs are known
/
the three C7H7 rings. Fluxional behaviour has been
observed for the coordination of other olefinic phos-
phanes 3c[12].
only in few cases. Thus, the sign of 1J(195Pt,31P) is
positive [16], and most likely, the sign of 2J(31P,13Ctrans
)
2.2.1. Intramolecular dynamics
is also positive. In all other cases, experimental evidence
of the coupling signs is desirable in order to make use of
the numerical values. Relative signs of coupling con-
stants can be readily obtained by appropriate one-
dimensional (1D) heteronuclear double resonance ex-
In the process of this intramolecular exchange, the
groups in cis- and trans-positions relative to phosphorus
do not exchange. This excludes a simple dissociative
mechanism for C7H7 ring exchange, since in an inter-

Table 1
31P, 195Pt and 13C NMR data a,b of 3aꢁ
/g, 3i and 4a
No.
d
31P
d
195Pt
d
13C(Ptꢀ
CHc3is -Me: ꢃ
/
R)
d
13C(C1)
d
13C(C2,7
)
d
13C(C3,6
)
d )
13C(C4,5
3a
99.7 (s) {2000} 291.5 (d) {2001}
/
2.9 (d) [3.8] {784.0} CHt3rans -Me: 15.7 (d) [116.6] {635.4}
2.7 (d) [9.0] CHt3rans -Me: 11.8 (d) [121.4]
34.1 (d) [21.8] {20.2} 117.6 (br) 127.1 (d) [9.8] 117.1 (br)
35.7 (d) [12.6] 118.3 (br) 127.9 (d) [9.5] 122.5 (br)
34.7 (d) [19.8] {19.5} 119.3 (s) 127.6 (d) [9.9] 116.6 (br)
4a c 72.9 (s)
ꢁ
/
CHc3is -Me: ꢃ
/
3b d 95.6 (s) {1820} 198.4 (d) {1818}
3c e 96.1 (s) {1829} 237.3 (d) {1829}
3d f 95.8 (s) {1833} 229.8 (d) {1833}
3e g 92.6 (s) {2223} 214.3 (d) {2223}
3f h 89.8 (s) {1975} 263.8 (d) {1975}
CHc2is -Et: 10.7 (d) [2.7] {864.5} CHt2rans -Et: 27.9 (d) [114.6] {707.7}
CHc2is -Pr: 20.9 (d) [2.8] {858.7} CHt2rans -Pr: 38.7 (d) [112.6] {705.4}
CHc2is -Bu: 18.4 (s) {862.5} CHt2rans -Bu: 35.8 (d) [112.9]
34.8 (d) [19.8] {19.5} 119.2 (br) 127.6 (d) [9.9] 99.3 (s)
34.7 (d) [19.7] {19.0} 119.1 (br) 127.4 (d) [9.8] 99.1 (s)
CHc2is -Bz: 22.7 (d) [3.2] {800.3} CHt2rans -Bz: 39.3 (d) [101.3] {605.2}
34.3 (d) [21.3] {18.8} 120.0 (s)
34.6 (d) [23.4] {16.4} 120.2 (s)
34.5 (d) [25.3] {16.1} 120.5 (s)
127.7 (d) [10.0] 116.6 (br)
127.2 (d) [11.3] 119.7 (br)
127.7 (d) [9.6] 119.8 (br)
117.7 (br) 130.6 (br) 127.3 (br)
Ph: 149.1 (d) [7.6] {1114.3} C
: 168.7 (d) [126.7] {842.7}
cis
trans-Ph
ipso
C
C
-
ipso
cis
: 142.3 (d) [10.3] C
ipso
3g i,j 89.8 (s) {2025} 281.9 (ddd) {2025} ꢃ31.7ꢄ ꢃ32.1ꢄ
: 162.5 (d) [118.5]
trans
ipso
3i k 99.4 (s) {2139} 235.8 (d) {2138}
Cc1is-Fc: 84.1 (d) [6.7] {1284.1} Ct1rans-Fc: 110.8 (d) [141.1] {975.6}
34.6 (d) [22.4]
a
Measurements in CDCl3 (25 8C); cis and trans refer to the position of R relative to phosphorus.
Coupling constants {} n J(195Pt,X), [ ] n J(31P,13C) in Hz.
Measurement in CD2Cl2 (25 8C).
b
c
d
e
f
d
13C(R): 14.9 (d, [5.4] {23.7}, CHt3rans -Et), 17.0 (s, {35.5}, CHc3is -Et).
d
13C(R):24.1 (d, [3.5] {7.6}, CHt2rans -Pr), 24.6 (s, {25.7}, CH2cis -Pr), 19.3 (s, {147.5}, CH3cis -Pr), 19.9 (d, [10.0] {92.6}, CH3trans -Pr).
13C(R): 28.0 (s, {137.4}, (CH2)c2is /trans -Bu), 28.4 (d, [9.9] {92.9}, (CH2)2cis /trans -Bu), 34.6 (s, (CH2)2cis /trans -Bu), 33.4 (d, [4.7], (CH2)2cis /trans -nBu), 14.0/14.5 (s/s, CH3cis /trans -Bu).
13C(R): 148.8 (d, [2.6] {56.0}, Cipso -cis ), 150.1 (d, [5.5] {48.9}, Cipso -trans ), 127.3 (s, {14.3}, Cmeta -cis ), 128.3 (d, [3.6] {26.2}, Cmeta -trans ), 127.4 (d, [1.8] {n.o.}, Cortho -trans ), 129.5 (s, {49.1},
Cortho -cis ), 122.1(d, [2.3] {15.1}, Cpara -trans ), 122.9 (s, {20.2}, Cpara-cis ).
d
g
d
h
d
13C(R): 127.3 (d, [1.7] {89.4}, Cmeta -cis ), 127.7 (d, [7.1] {61.1}, Cmeta -trans ), 135.3 (s, {32.0}, Cortho -cis ), 135.4 (d, [2.6] {29.0}, Cortho-trans ), 121.9 (d, [1.6] {14.1}, Cpara -trans ), 122.5 (d, [1.1] {10.1},
Cpara-cis ).
i
ꢃꢄ: 5J(195Pt, 19F) or n J(19F,13C) in Hz.
j
d
13C(R): 114.1 (d, 1ꢃ8.6ꢄ {97.2}, Cmeta-cis ), 114.4 (dd, [8.9] 17.8 {n.o.}, Cmeta-trans ), 135.3 (dd, [2.5] ꢃ5.3ꢄ {n.o.}, Cortho-trans ), 135.4 (d, 5.5 {40.5}, Cortho-cis ).
k
d
13C(R): 75.1/ 77.2 (d/d, [5.6] {57.0}/[5.0] {79.1}, C2,5(Fc)-trans /cis ), 67.8/ 69.2 (s/s, C3,4(Fc)-cis /trans ), 67.4/ 68.2 (s/s, Ccis /trans -Cp(Fc)).

54
M. Herberhold et al. / Inorganica Chimica Acta 352 (2003) 51ꢁ60
/
Table 2
31P, 1H and 13C NMR data a of 3h and 4h
No.
3h
4h
(1) d31P b
97.8 (s) {2707}
101.0 (m)
d
(2) d1H c
Free rings:
H1
2.14 (dt, 2H) (6.7) [9.0] 1.97 (dt, 2H) (6.6) [8.4]
H2,7
4.83 (m, 2H) [7.0]
5.09 (m, 2H) [6.4]
6.25 (m, 4H)
4.73 (m, 2H) [7.3]
5.07 (m, 2H) [7.1]
6.23 (m, 4H)
H3,6
H4,5
6.63 (m, 4H)
6.62 (m, 4H)
Coordinated ring:
H1?
4.80 (m, 1H)
4.45 (dt, 1H) (8.6) [13.1]
5.81 (m, 2H) [8.6]
6.72/6.62 (m/m, 4H)
H2?,7?
H3?,6?
H4?,5?
5.83 (m, 2H) [9.1]
6.56 (m, 2H)
6.05 (m, 2H) {44.3}
(3) d13P e
Free rings:
C1
f
35.0 (d) [32.7] {45.2}
113.7 (s) {17.4}
114.3 (s) {16.7}
127.0 (d) [11.0]
127.4 (d) [10.5]
131.0 (s)
35.4 (d) [24.9]
114.3 (s)
115.2 (s)
C2,7
C3,6
C4,5
126.9 (d) [11.3]
127.3 (d) [9.8]
130.9 (s)
131.2 (s)
131.1(s)
Coordinated ring:
C1?
36.3 (d) [22.1] {17.2}
129.9 (s) {49.6}
130.4 (d) [10.3]
93.8 (s) {51.7}
38.5 (d) [12.2]
130.5 (s)
C2?,7?
C3?,6?
C4?,5?
130.3 (d) [9.7]
107.5 (s)
a
Measurements in CD2Cl2 at 25 8C; 13C NMR data of C6F5 groups
not assigned.
b
Coupling Constant {} 1J(195Pt,31P) in Hz.
Coupling Constants {} n J(195Pt,1H), [ ] 2J(31P,1H), () n J(1H,1H) in
c
Hz.
d
Fig. 1. (A) 250 MHz 1H NMR spectra of [P]PtMe2 (3a) (in CD2Cl2) at
room temperature and at ꢃ50 8C. Note that the PtMe groups show
Measurement at ꢃ20 8C.
/
e
f
Coupling constants {} n J(195Pt,13C), [ ] 1J(31P,13C) in Hz.
Measurement at 0 8C.
/
nicely resolved different signals in spite of the dynamic process
involving the intramolecular exchange of the C7H7 rings. (B) 62.9
MHz 13C{1H} NMR spectrum of [P]PtMe2 (3a) (in CDCl3) at room
temperature. The 13C(PtMe) signals are different, whereas the
13C(C7H7) signals are broad or sharp singlets owing to exchange of
the C7H7 rings.
periments [17] or by 2D heteronuclear shift correlations
(HETCOR) [18], in which one nucleus (neither irra-
diated nor observed) is the passive spin, and the other
two (irradiated or observed) are the active spins. The
coupling signs to be compared refer to couplings
between the active and the passive spins.
1J(195Pt,31P) (ꢀ0) and 3J(31P,Pt,C,1Hcis) are alike.
/
1
From H/1H COSY experiments carried out for 3b, by
The results of typical 1D experiments are shown in
observing the 195Pt satellite cross peaks, it follows that
Fig.
3
for [P]PtMe2 3a, where the signs of
3
the sign of J(195Pt,1HEt) is positive. For the coordi-
3J(31P,Pt,C1,H) and 1J(195Pt,31P) are compared via
selective heteronuclear 1H{195Pt} double resonance
experiments. Figs. 4 and 5 show typical examples of
the application of 2D HETCOR experiments. In the
case of 3a, a negative tilt of the 195Pt satellite cross peaks
is observed for both PtMe groups in 31P/1H shift
1
nated h2-Cꢁ
/
C bond, the sign of J(195Pt,13C) is also
positive, and that of 2J(195Pt,1H) is negative. The
magnitude of the coupling constants ½3J(31P,Pt,C,1H)½
is almost identical for both PtMe groups in 3a (7.6 and
6.8 Hz). However, their signs are opposite (Fig. 3), a
negative sign is found for 3J(31P,Pt,C,1Htrans) and a
positive sign for 3J(31P,Pt,C,1Hcis). The data
correlations.
1J(195Pt,13CMe,Et
2J(195Pt,1HMe,Et) are negative. The 195Pt/1H shift corre-
lation shown in Fig. 5 for CH2 of the ethyl group in cis-
position with respect to phosphorus, proves that
As
)
expected
[19],
all
signs
are positive, and all signs
2J(195Pt,13C1,1?) are also of interest since the absolute
2
sign of J(195Pt,13C1) (ꢀ
/
0) has been determined in a
non-fluxional cationic complex {[P]Pt(Cp)}ꢂ [7]. In 3h

M. Herberhold et al. / Inorganica Chimica Acta 352 (2003) 51ꢁ
/60
55
Fig. 3. Heteronuclear 1H{195Pt} spin tickling experiment, showing the
1H(PtMe) resonances of 3a upon low power selective irradiation of the
195Pt transitions (transitions influenced by irradiation with the 195Pt
frequency are indicated by asterisks). This compares the signs of
Fig. 2. (A) 250 MHz 1H NMR spectrum of [P]Pt(C6F5)2 (3h) (in
CD2Cl2) at room temperature. The dynamic process of exchanging
C7H7 rings is slow on the NMR time scale and most signals for
coordinated and non-coordinated C7H7 rings are clearly resolved
(satellites due to J(195Pt,1H) are marked by asterisks). (B) 62.9 MHz
13C{1H} NMR spectrum of [P]Pt(C6F5)2 (3h) (in CD2Cl2) at room
temperature. The signals for coordinate and non-coordinate C7H7
1J(195Pt,31P) (ꢀ0) with those of 3J(31P,Pt,C,1HMe-cis /trans ). The sign of
/
the latter coupling constant involving of the 1H(PtMecis ) nuclei at
higher frequency is positive whereas the other one for 1H(PtMetrans ) at
lower frequency is negative (note that the absolute magnitudes of these
coupling constants 3J(31P,Pt,C,1H) are almost identical).
rings are resolved (doublets due to J(31P,13C) are marked by ꢂ
/
and
satellites due to J(195Pt,13C) are marked by *).
taken by the C6H4ꢁ4-F groups, of which the benzene
/
ring planes are oriented almost perpendicular (83.98) to
each other. This particular geometry, present only in the
solid state, appears to be typical of diaryl-Pt(II) com-
(see Fig. 2), the magnitude of ½2J(195Pt,13C1?)½ (17.2 Hz)
and ½2J(195Pt,13C1)½ (45.2 Hz) can be measured, whereas
in the other complexes studied here only the averaged
magnitude ½2J(195Pt,13C1,1?)½ was accessible. These mean
plexes [20,21]. The plane of the C6H4ꢁ4-F group in
/
trans-position with respect to the h2-coordinated Cꢁ
/C
bond is twisted by only 8.48 against the PtCC plane. For
clarity, the coordination geometry of platinum and the
values (:20 Hz) indicate that the signs of the coupling
/
constants 2J(195Pt,13C1?) and 2J(195Pt,13C1) are most
likely opposite. A similar trend is also evident for the
values ½2J(195Pt,13C1,1?)½ in the halides [P]PtX2 [6].
positions of the C6H4ꢁ
Fig. 7. Since the arrangement of the C6H4ꢁ
/
4-F ligands are shown in detail in
4-F groups is
/
not enforced by steric constraints, (dp)p interactions
between platinum and the aryl groups are likely, in
agreement with the changes in the 13C(4) nuclear
magnetic shielding in solution when compared with
2.3. X-ray structural analysis of [P]Pt(C6H4ꢁ
/
4-F)2
(3g)
C6H6 and C6H5ꢁ
/
F. Although aryl rotation about the
C(aryl) axis is fast in solution, the 13C(4) chemical
Ptꢀ
/
The molecular structure of 3g is shown in Fig. 6,
together with selected bond lengths and angles. The
phosphane [P] acts as a bidentate chelating ligand which
occupies two adjacent positions of the square planar
arrangement around the platinum atom (mean deviation
from plane: 5 pm). The remaining two positions are
shifts indicate preference of a preferred conformation
which, most likely, corresponds to that found for the
solid state. As in other [P]Pt(L)(L?) complexes (cf. [6,9ꢁ
11]), where the PtꢀL bond trans to phosphorus is longer
than the Ptꢀ
L? bond trans to the h2-coordinated Cꢁ
/
/
/
/C

56
M. Herberhold et al. / Inorganica Chimica Acta 352 (2003) 51ꢁ60
/
Fig. 6. Molecular structure of [P]Pt(C6H4 ꢁ
are omitted for clarity). Selected bond lengths [pm] and angles
[degrees]: PtꢀP 229.37(17), PtꢀC(22) 203.5(6), PtꢀC(28) 207.7(6),
PtꢀC(4) 229.7(7), PtꢀC(5) 231.3(6), C(1)ꢀC(2) 150.5(10), C(1)ꢀ
151.4(10), C(2)ꢀC(3) 133.5(10), C(3)ꢀC(4) 146.9(10), C(4)ꢀ
138.6(10), C(5)ꢀC(6) 144.8(11), C(6)ꢀC(7) 131.6(11), C(11)ꢀ
132.0(14), C(18)ꢀC(19) 134.9(12), PꢀC(1) 187.5(7), Pꢀ
PꢀC(15) 184.8(7), C(25)ꢀF(1) 137.1(8), C(31)ꢀ
PtꢀC(28) 85.9(2), C(22)ꢀPtꢀP 92.47(18), C(28)ꢀ
C(22)ꢀPtꢀC(4) 162.9(3), C(22)ꢀPtꢀC(5) 161.5(3), C(28)ꢀ
90.0(3), C(28)ꢀPtꢀC(5) 91.1(3), PꢀPtꢀC(4) 91.78(18), Pꢀ
90.21(19).
/
4-F)2 (3g) (hydrogen atoms
/
/
/
/
/
/
/
C(7)
/
/
/C(5)
/
/
/C(12)
/
/
/C(8) 185.8(7),
/
/
/
F(2) 138.5(9); C(22)ꢀ
/
/
/
/
/
PtꢀP 178.22(19),
/
Fig. 4. Contour plot of the 2D 101.25 MHz 31P/1H HETCOR
/
/
/
/
/
Ptꢀ
/
C(4)
experiment based on the coupling constants 3J(31P,Pt,C,1HMe):
7
/
/
/
/
/
/
Ptꢀ
/C(5)
Hz. The negative tilt of the cross peaks for the 195Pt satellites proves
that for both methyl groups the signs of the coupling constants
2J(195Pt,1H) and 1J(195Pt,31P) are opposite. Since the latter sign is
known to be positive, it follows that 2J(195Pt,1H)B
0.
/
bond, the respective Ptꢀ
lengths in 3g differ in a similar way (207.7(6) and
203.5(6) pm). The PtꢀC(4) and Ptꢀ
C(5) bonds (h2-
coordinated CꢁC bond) are almost identical (229.7(7)
and 231.3(6) pm), and they are longer than the bonds
/
C(28) and Ptꢀ/C(22) bond
/
/
/
Fig. 5. Contour plot of the 2D 53.5 MHz 195Pt/1H HETCOR
101 Hz,
experiment based on the coupling constant 2J(195Pt,1HEt)ꢀ
/
using a BIRD pulse sequence for homonuclear 1H,1H decoupling. The
part of the 1H(CHc2is ) resonances is shown, with a splitting due to
3J(31P,Pt,C,1H), and a positive tilt of the cross peaks which indicates
that the signs of the coupling constants 1J(195Pt,31P) and
3J(31P,Pt,C,1H) are alike.
Fig. 7. The geometry around platinum in [P]Pt(C6H4 ꢁ
determined by X-ray analysis. Note the orientation of the C6H4 ꢁ
groups, the dihedral angle between the two 4-fluorophenyl ring planes
is 83.98.
/
4-F)2 (3g) as
4-F
/

M. Herberhold et al. / Inorganica Chimica Acta 352 (2003) 51ꢁ
/60
57
Ptꢀ
rings are linked to the phosphorus atom by equatorial
PꢀC bonds. This suggests that the bonding situation of
the ligand [P] has to change considerably in going from
the solid to the solution state (in contrast to one example
of a Rh(I) complex noted in the literature [13]). The
dynamic process in solution requires spatial proximity
of at least a second C7H7 ring to the platinum atom, and
/
C(28) and Ptꢀ
/
C(22). Both non-coordinated C7H7
195Pt), were optimised in 1D INEPT experiments.
Because of fast 195Pt nuclear spin relaxation (chemical
shift anisotropy relaxation mechanism, dependent on
B02), the 195Pt/1H shift correlations gave a better
performance at lower field strengths B0.
/
EI MS: Finnigan MAT 8500 (Ionisation energy 70
eV).
also an axial Pꢀ
/
C bond of this particular ring in order to
4.2. Synthesis of [P]PtMe2 (3a)
substitute the coordinated ring. These features are not
observed in the solid-state molecular structure of 3g.
A suspension of [P]PtCl2 (1) (171 mg, 0.30 mmol) in a
toluene/Et2O mixture (20 ml/5 ml) was reacted with 0.5
ml of a 1.6 M MeLi/Et2O solution (0.8 mmol) at ꢃ
78 8C. The reaction mixture was allowed to warm up
to room temperature and stirred for further 30 min,
/
3. Conclusions
The synthesis of stable complexes of Pt(II) and Pd(II)
containing the bidentate ligand [P] and two organyl
groups R is straightforward. These complexes are
fluxional, the Pd(II) more than the Pt(II) species, with
before it was cooled again to ꢃ78 8C and an excess of
/
water was added. The mixture was again brought to
ambient temperature, the organic layer was separated
and the solvent was removed in vacuo. The residue was
washed with hexane (50 ml), recrystallized from CH2Cl2/
hexane and dried in a high vacuum.
respect to h2-Cꢁ
/C coordination of the C7H7 rings in [P].
In this dynamic process, the stereochemistry of the
groups R remains fixed, pointing towards an associative
mechanism involving a transition state with five-coordi-
nate Pt. There is a wealth of coupling constants available
in the complexes studied. Although most of the coupling
signs are found as expected, in several cases opposite
signs were determined or had to be invoked in order to
make use of the numerical values.
4.2.1. [P]PtMe2 (3a)
Bright-yellow powder, dec. 159 8C, yield 125 mg
(79%). 1H NMR (CDCl3, 25 8C): dꢀ
/
0.54 (d, 3H,
7.6 Hz, J(195Pt,1H)ꢀ
63.3 Hz),
Hcis-Me 2J(31P,1H)ꢀ
6.8 Hz,
99.0 Hz), 3.91 (br, 3H, H1), 5.28 (m,
6H, H2,7), 6.12 (br, 6H, H4,5), 6.20 (m, 6H, H3,6).
2
3
Htrans-Me; J(31P,1H)ꢀ
1.02 (d, 3H,
3J(195Pt,1H)ꢀ
/
/
;
/
/
C23H27PPt,
EI
MS:
m/e
(%)ꢀ
/
514
(73)
4. Experimental section
[P(C7H7)3PtMeꢂ], 423(4) [P(C7H7)2PtMeꢂ], 332(5)
[P(C7H7)PtMeꢂ], 91(100) [C7H7ꢂ].
4.1. General and starting materials
4.3. Synthesis of [P]PdMe2 (4a)
All compounds were synthesized and handled in an
atmosphere of dry argon, and carefully dried solvents
were used throughout. Starting materials were prepared
according to literature procedures, e.g. P(C7H7)3 [5],
[P]MCl2 (1) and 2 [6], and FcLi [22], or were used as
commercial products without further purification, e.g.
An ethereal solution of 1.6 M MeLi (0.8 ml, 1.3
mmol) was added to a suspension of [P]PdCl2 (2) (120
mg, 0.25 mmol) in a toluene/Et2O mixture (20 ml/5 ml)
at ꢃ
brought to room temperature and then stirred for 1.5
h. Hydrolysis with water (30 ml) at ꢃ50 8C gave a two-
/
78 8C. The reaction mixture was immediately
Mg, RBr (Rꢀ
/
Et, Pr, Bu, CH2Ph, Ph, C6F5), 4-Fꢁ
/
/
C6H4MgBr (1 M in THF), MeLi (1.6 M in Et2O) and
nBuLi (1.6 M in hexane).
phase mixture. After filtration the organic layer was
separated and the solvents removed in vacuo. The
remaining residue was dissolved in CH2Cl2 (2 ml) and
pentane was added (20 ml). The bright-brown product
4.1.1. NMR spectroscopy
Bruker ARX 250 or DRX 500 (1H, 13C, 31P, 195Pt
NMR); chemical shifts are given with respect to Me4Si
4a which precipitated at ꢃ80 8C overnight was dried
/
[d1H (CD(H)Cl2)ꢀ
/
5.33; d13C (CD2Cl2)ꢀ
0 for J(31P)ꢀ
for J(195Pt)ꢀ
21.400000 MHz. Heteronuclear 1H{X} experiments
(Xꢀ31P, 195Pt) were carried out by using the known
(from X NMR spectra) frequencies for the X transitions,
and by adjusting the power level (usually values ꢀ40
dB) in order to induce the selective effects. The 2D
HETCOR experiments, based on J(X,1H) (Xꢀ13C, 31P,
/
50.3; external
under high vacuum.
aqueous H3PO4 (85%) with d31Pꢀ
40.480747 MHz, and
195Ptꢀ
/
/
d
/0
/
4.3.1. [P]PdMe2 (4a)
Bright-brown powder, dec. 127 8C, yield 67 mg (61%).
/
1H NMR (CDCl3, 25 8C): dꢀ
2J(31P,1H)ꢀ7.3 Hz), 0.49 (d, 3H, Htrans-Me
2J(31P,1H)ꢀ
/
0.16 (d, 3H, Hcis-Me
;
;
/
/
/
8.0 Hz), 2.74 (dt, 3H, H1; 2J(31P,1H)ꢀ
/
7.4 Hz, J(1H,1H)ꢀ
/
7.4 Hz), 5.27 (m, 6H, H2,7), 6.26
3
/
(m, 6H, H4,5), 6.48 (m, 6H, H3,6). C23H27PPd, EI MS:

58
M. Herberhold et al. / Inorganica Chimica Acta 352 (2003) 51ꢁ60
/
m/e (%)ꢀ
/
425(1) [P(C7H7)3PdMeꢂ], 410 (B
/
1)
[Mꢂ],
590(100)
[P(C7H7)3PtBzꢂ],
408(7)
[P(C7H7)2Ptꢂ],
499(8)
304(2)
[P(C7H7)3Pdꢂ], 91 (100) [C7H7ꢂ].
[P(C7H7)3Ptꢂ],
[P(C7H7)3ꢂ], 91(91) [C7H7ꢂ].
4.4. General procedure for the synthesis of [P]PtR2
(RꢀEt 3b, Pr 3c, Bu 3d, Bz 3e, Ph 3f)
/
4.4.5. [P]PtPh2 (3f)
Bright-yellow powder, dec. 127 8C, yield 265 mg
(81%), 1H NMR (CDCl3, 25 8C): dꢀ
2.77 (br, 3H,
H1), 5.18 (m, 6H, H2,7), 6.26 (m, 6H, H3,6), 6.31 (br,
6H, H4,5), 6.57ꢁ7.68 (m, 10H, Hcis/trans-Ph). C33H31PPt,
EI MS: m/e (%)ꢀ
499(5) [P(C7H7)3Ptꢂ], 408(6)
[P(C7H7)2Ptꢂ], 304(1) [P(C7H7)3ꢂ], 154(100) [C6H5ꢀ
C6H5ꢂ], 91(51) [C7H7ꢂ], 78(12) [C6H6ꢂ].
At 0 8C solid [P]PtCl2 (1) (285 mg, 0.5 mmol) was
added to a RMgBr solution, which had been prepared
/
from Mg (50 mg, 2.1 mmol) and RBr (RꢀEt, Pr, Bu,
/
/
Bz) (2.00 mmol) in Et2O (20 ml). The reaction mixture
was stirred for 4 h at 0 8C, then a cold saturated,
aqueous NH4Cl solution was added. The organic layer
was separated and the solvent was removed in vacuo.
The residue was recrystallized from CH2Cl2/hexane and
dried in a high vacuum.
/
/
4.5. Synthesis of [P]Pt(C6H4ꢁ
/
4-F)2 (3g)
A 1.0 M BrMgC6H4ꢁ4-F solution (2.6 ml, 2.6 mmol)
/
4.4.1. [P]PtEt2 (3b)
in THF was added to a suspension of [P]PtCl2 1 (285
mg, 0.50 mmol) in Et2O (15 ml) at 0 8C. The reaction
mixture was stirred at room temperature for 3.5 h. After
hydrolysis with water (10 ml) at 0 8C, the organic layer
was separated and brought to dryness in vacuo. The
residue was recrystallized from CH2Cl2/pentane and
dried in a high vacuum.
Bright-yellow powder, dec. 165 8C, yield 242 mg
1
(87%). H NMR (CDCl3, 25 8C): dꢀ
/
1.07 (t, 3H, Hcis-
3
3
Et; J(195Pt,1H)ꢀ
/
100.7 Hz, J(1H,1H)ꢀ
7.8 Hz), 1.13
/
(m, 2H, Htrans-Et; J(31P,1H)ꢀ
/
8.5 Hz, J(1H,1H)ꢀ
3J(195Pt,1H)ꢀ
64.7 Hz,
6.1 Hz), 1.83 (m, 2H,
95.0 Hz, 3J(31P,1H)ꢀ
8.0 Hz,
7.4 Hz), 2.89 (br, 3H, H1), 5.32 (m, 6H,
H2,7), 6.16 (m, 6H, H3,6), 6.20 (br, 6H, H4,5). C25H31PPt,
/6.5
3
3
Hz), 1.26 (dt, 3H, Htrans-Et
;
/
4J(31P,1H)ꢀ
Hcis-Et
3J(1H,1H)ꢀ
/
8.2 Hz, J(1H,1H)ꢀ
/
3
;
2J(195Pt,1H)ꢀ
/
/
4.5.1. [P]Pt(p-C6H4F)2 (3g)
Bright-yellow powder, dec. 161 8C, yield 245 mg
/
(71%), 1H NMR (CDCl3, 25 8C): dꢀ
2.76 (br, 3H,
/
EI MS: m/e (%)ꢀ
528(3) [P(C7H7)3PtEtꢂ]; 499(20)
/
H1), 5.19 (m, 6H, H2,7), 6.26 (m, 6H, H3,6), 6.29 (br,
6H, H4,5), 6.54/6.81 (m/m, 2H/2H, Hmeta-cis/trans), 7.01/
7.43 (m/m, 2H/2H, Hortho-cis/trans). C33H29F2PPt, EI MS:
[P(C7H7)3Ptꢂ]; 408(5) [P(C7H7)2Ptꢂ], 91(100) [C7H7ꢂ].
4.4.2. [P]PtPr2 (3c)
Yellow powder, dec. 111 8C, yield 211 mg (72%). H
m/e (%)ꢀ
[P(C7H7)3Ptꢂ],
[C6H4Fꢀ
C6H4Fꢂ], 91(100) [C7H7ꢂ].
/
503(1) [P(C7H7)2Pt(C6H4F)ꢂ], 499(7)
408(6) 190(26)
[P(C7H7)2Ptꢂ],
1
NMR (CDCl3, 25 8C): dꢀ
/
0.80 (t, 3H, Hcis/trans-Pr
;
;
/
3J(1H,1H)ꢀ7.0 Hz), 1.04 (t, 3H, Hcis/trans-Pr
/
3J(1H,1H)ꢀ
/
7.2 Hz), 1.10ꢁ1.97 (m/m/m/m, 8H,
/
Hcis/trans-Pr), 2.90 (br, 3H, H1), 5.31 (m, 6H, H2,7), 6.16
4.6. General procedure for the synthesis of [P]M(C6F5)2
(MꢀPt 3h, MꢀPd 4h)
(m, 6H, H3,6), 6.20 (br, 6H, H4,5). C27H35PPt, EI MS: m/
/
/
e (%)ꢀ
542(2) [P(C7H7)3PtPrꢂ], 499(9) [P(C7H7)3Ptꢂ],
/
304(8) [P(C7H7)3ꢂ], 91(100) [C7H7ꢂ].
A C6F5Li solution (:0.45 mmol) was freshly pre-
/
pared from C6F5Br (60 ml, 121 mg, 0.49 mmol) and a 1.6
M BuLi/Et2O solution (0.3 ml, 0.49 mmol) in Et2O (5
ml). Then Et2O (15 ml) was added and the solution
4.4.3. [P]PtBu2 (3d)
Yellow powder, dec. 124 8C, yield 233 mg (76%), H
1
cooled to ꢃ
/
78 8C, before [P]MCl2 (0.15 mmol; MꢀPt
/
NMR (CDCl3, 25 8C): dꢀ
3J(1H,1H)ꢀ7.2 Hz), 0.92 (t, 3H, Hcis/trans-Bu
3J(1H,1H)ꢀ
/
0.74 (t, 3H, Hcis/trans-Bu
;
;
1, MꢀPd 2) was added. The reaction mixture was
/
/
brought to room temperature within 3 h and then stirred
for one more hour. The small excess of C6F5Li was
destroyed by addition of ice-water (10 ml) at 0 8C. The
organic layer was separated and the solvent was
removed in vacuo. The product was recrystallized
from CH2Cl2/hexane and dried under high vacuum.
/
7.3 Hz), 1.08ꢁ
/
1.82 (m/m/m/m, 12H,
Hcis/trans-Bu), 2.90 (br, 3H, H1), 5.31 (m, 6H, H2,7),
6.15 (m, 6H, H3,6), 6.20 (br, 6H, H4,5).
4.4.4. [P]PtBz2 (3e)
1
Yellow powder, dec. 133 8C, yield 259 mg (76%), H
NMR (CDCl3, 25 8C): dꢀ ;
2.71 (d, 2H, Htrans-Bz
/
2J(31P,1H)ꢀ
3H, H1), 3.28 (d, 2H, Hcis-Bz
3J(195Pt,1H)ꢀ122.6 Hz), 5.38 (m, 6H, H2,7), 6.13 (br,
6H, H4,5), 6.23 (m, 6H, H3,6), 6.80ꢁ
7.35 (m, 10H,
Hcis/trans-Bz). C35H35PPt, EI MS: m/e (%)ꢀ
681(1)
/
11.2 Hz, J(195Pt,1H)ꢀ
/
91.0 Hz), 2.93 (br,
3
4.6.1. [P]Pt(C6F5)2 (3h)
White powder, dec. 129 8C, yield 101 mg (81%).
;
2J(31P,1H)ꢀ
/
7.2 Hz,
/
/
4.6.2. [P]Pd(C6F5)2 (4h)
White powder, dec. 88 8C, yield 70 mg (63%).
/

M. Herberhold et al. / Inorganica Chimica Acta 352 (2003) 51ꢁ
/60
59
4.7. Synthesis of [P]PtFc2 (3i)
mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
Solid FcLi (230 mg, 1.2 mmol) was added to a
solution of [P]PtCl2 (1) (228 mg, 0.4 mmol) in toluene
(20 ml) at ꢃ10 8C. The cooling bath was then removed
/
Acknowledgements
and the mixture stirred for further 5 h at room
temperature. After hydrolysis with water (20 ml) at
0 8C, the organic layer was separated and brought to
dryness in vacuo. Ferrocene was sublimed off from the
red solid at 60 8C in a high vacuum. Recrystallization
from CH2Cl2/hexane and drying under high vacuum
gave a red powder.
Support of this work by the Deutsche Forschungsge-
meinschaft and the Fonds der Chemischen Industrie is
gratefully acknowledged.
References
4.7.1. [P]PtFc2 (3i)
Red powder, dec. 132 8C, yield 236 mg (80%), 1H
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Mono-Olefinic Ligands, Part 2, Specific Aspects, Elsevier Scien-
tific, Amsterdam, 1974;
NMR (CDCl3, 25 8C): dꢀ
3.42 (br, 3H, H1), 3.90/4.27
/
(s/s, 5H/5H, Hcis/trans-Cp), 4.18/4.24 (m/m, 2H/2H,
Hcis/trans-Fc), 4.32/4.42 (m/m, 2H/2H, H cis/trans-Fc), 5.38
(m, 6H, H2,7), 6.35 (m, 6H, H3,6), 6.63 (m, 6H, H4,5).
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1979;
C41H39Fe2PPt, EI MS: m/e (%)ꢀ
/
370(27) [Fc2ꢂ],
304(66) [P(C7H7)3ꢂ], 185(36) [Fcꢂ], 91(100) [C7H7ꢂ].
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4.8. Crystal structure analysis of [P]Pt(C6H4ꢁ
(3g)
/
4-F)2
The intensity data were collected on a STOE IPDS
image plate system with Mo Ka radiation (lꢀ71.073
/
(b) M.A. Bennett, W.R. Kneen, R.S. Nyholm, Inorg. Chem. 7
(1968) 556;
pm, graphite monochromator) at room temperature.
The hydrogen atoms are in calculated positions. All
non-hydrogen atoms were refined with anisotropic
temperature factors. The hydrogen atoms were refined
applying the riding model with fixed isotropic tempera-
ture factors.
(c) M.A. Bennett, W.R. Kneen, R.S. Nyholm, J. Organomet.
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4.8.1. C33H29F2PPt (3g)
Yellow prism of dimensions 0.35ꢄ
crystallizes monoclinically, space group P21/n;
aꢀ1365.6(3), bꢀ1459.7(3), cꢀ1494.0(3) pm,
bꢀ109.52(3)8, Zꢀ4, mꢀ
5.089 mmꢃ1; 20750 reflec-
tions collected in the range 2ꢁ268 in q, 5042 reflections
independent, 3785 reflections assigned to be observed
(I ꢀ2s(I)); full matrix least-squares refinement with
/
0.12ꢄ
/
0.08 mm,
[6] M. Herberhold, T. Schmalz, W. Milius, B. Wrackmeyer, Z.
Anorg. Allg. Chem. 628 (2002) 437.
/
/
/
[7] M. Herberhold, T. Schmalz, W. Milius, B. Wrackmeyer, Inorg.
Chim. Acta 334 (2002) 10.
/
/
/
/
[8] M. Herberhold, T. Schmalz, W. Milius, B. Wrackmeyer, Z.
Naturforsch. B 57 (2002) 53.
[9] M. Herberhold, T. Schmalz, W. Milius, B. Wrackmeyer, Z.
Anorg. Allg. Chem. 628 (2002) 971.
/
334 parameters, R1/wR2-values 0.041/0.095, absorption
correction (numerical); max/min residual electron den-
[10] M. Herberhold, T. Schmalz, B. Wrackmeyer, Z. Naturforsch. B
57 (2002) 255.
sity 2.83/ꢃ
/
1.03ꢄ .
10ꢃ6 e pmꢃ3
/
[11] M. Herberhold, T. Schmalz, W. Milius, B. Wrackmeyer, J.
Organomet. Chem. 641 (2002) 173.
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443.
5. Supplementary information
[13] (a) M.A. Alonso, J.A. Casares, P. Espinet, K. Soulantica, Angew.
Chem. 111 (1999) 554;
Crystallographic data (excluding structure factors) for
the structure reported in this paper have been deposited
with the Cambridge Crystallographic Data Centre as
supplementary publication CCDC No. 184030 (3g).
Copies of the data can be obtained free of charge on
application to The Director. CCDC, 12 Union Road,
(b) M.A. Alonso, J.A. Casares, P. Espinet, K. Soulantica, Angew.
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