Reactions of (σ-alkynyl)platinum complexes with [Pd(η3-C3H5)Cl]2. Synthesis of bis(η2-alkyne)(η3-allyl)palladiuin(II) complexes. Crystal and molecular structure

Article abstract of DOI:10.1021/om9603326

The σ-bis and tetraalkynyl anions [cis-Pt(C₆F₅)₂(C≡CR)₂] ^2- and [Pt(C≡CR)₄]^2- (R = Ph, ^tBu, SiMe₃) have been shown to be useful reagents for the formation of bis(μ-alkynyl) complexes via halide displacement reactions. They thus react with {[Pd(η³-C₃H₅)Cl]₂} in a 2:1 molar ratio to form anionic heterobinuclear zwitterionic Q[cis-(C₆F₅)₂Pt(μ-η ¹:η²-C≡CR)₂Pd-(η ³-C₃H₅)] (Q = PMePh₃, R = Ph; Q = NBu₄, R = ^tBu, SiMe₃ 1a-c) and (NBu₄)[(RC≡C)₂Pt-(μ-η¹:η ²-C≡CR)₂Pd(η³-C₃H ₅)] (R = Ph, ^tBu, SiMe₃ 2a-c) complexes. The corresponding trinuclear 1:2 neutral adducts {[Pt(C≡CR)₄][Pd(η³-C₃H ₅)]₂) (R = Ph, ^tBu, SiMe₃ 3a-c) were formed by the addition of 1 equiv of the tetraalkynyl anions to {[Pd(η³-C₃H₅)Cl]₂}. Binuclear derivative analogue [(PPh₃)₂Pt(μ-η¹:η ²-C≡CR)Pd(η³-C₃H ₅)](ClO₄) (R = Ph, ^tBu 4a,b) were produced by the reaction of {[Pd(η³-C₃H₅)Cl]₂} with neutral [cis-Pt(PPh₃)₂(C≡CR)₂] (1:2 ratio) in the presence of NaClO₄ (excess). The heterobimetallic anionic 1c (R = SiMe₃) and cationic 4b (R = ^tBu) complexes were characterized by X-ray diffraction. In both, the two bridging alkynyl ligands remained σ bonded to the platinum center and η² coordinated to the palladium one.

Full text of DOI:10.1021/om9603326

Organometallics 1996, 15, 4537-4546
4537
Rea ction s of (σ-Alk yn yl)p la tin u m Com p lexes w ith
[P d (η3-C3H5)Cl]2. Syn th esis of
Bis(η2-a lk yn e)(η3-a llyl)p a lla d iu m (II) Com p lexes. Cr ysta l
a n d Molecu la r Str u ctu r e of
[cis-(P P h 3)2P t(µ-η1:η2-CtCtBu )2P d (η3-C3H5)](ClO4)
J esu´s R. Berenguer,† J uan Fornie´s,*,‡ Elena Lalinde,*,† and Francisco Mart´ınez‡
Departamento de Qu´ımica, Universidad de La Rioja, 26001 Logron˜o, Spain, and
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza-Consejo Superior de Investigaciones Cient´ıficas,
50009 Zaragoza, Spain
Received May 3, 1996X
The σ-bis and tetraalkynyl anions [cis-Pt(C6F5)2(CtCR)2]2- and [Pt(CtCR)4]2- (R ) Ph,
tBu, SiMe3) have been shown to be useful reagents for the formation of bis(µ-alkynyl) com-
plexes via halide displacement reactions. They thus react with {[Pd(η3-C3H5)Cl]2} in a 2:1
molar ratio to form anionic heterobinuclear zwitterionic Q[cis-(C6F5)2Pt(µ-η1:η2-CtCR)2Pd-
(η3-C3H5)] (Q ) PMePh3, R ) Ph; Q ) NBu4, R ) tBu, SiMe3 1a -c) and (NBu4)[(RCtC)2Pt-
(µ-η1:η2-CtCR)2Pd(η3-C3H5)] (R ) Ph, tBu, SiMe3 2a -c) complexes. The corresponding trinu-
clear 1:2 neutral adducts {[Pt(CtCR)4][Pd(η3-C3H5)]2} (R ) Ph, tBu, SiMe3 3a -c) were formed
by the addition of 1 equiv of the tetraalkynyl anions to {[Pd(η3-C3H5)Cl]2}. Binuclear deriva-
tive analogue [(PPh3)2Pt(µ-η1:η2-CtCR)Pd(η3-C3H5)](ClO4) (R ) Ph, tBu 4a ,b) were produced
by the reaction of {[Pd(η3-C3H5)Cl]2} with neutral [cis-Pt(PPh3)2(CtCR)2] (1:2 ratio) in the
presence of NaClO4 (excess). The heterobimetallic anionic 1c (R ) SiMe3) and cationic 4b
(R ) tBu) complexes were characterized by X-ray diffraction. In both, the two bridging alkyn-
yl ligands remained σ bonded to the platinum center and η2 coordinated to the palladium one.
In tr od u ction
this, the reactivity of allylpalladium complexes toward
other metal derivatives has attracted somewhat less
attention.2a,3 This fact is surprising in view of the
established value of bi- and polymetallic species as
polyfunctional catalysts.4
The bridge-assisted synthetic method has proved to
be one of the most flexible routes to heterobimetallic
complexes with bridging ligands of all sorts.4b,c We5 and
Allylpalladium complexes play a prominent role as
potential precursors or intermediates in several pal-
ladium-catalyzed organic syntheses.1 As a result, a
large number of allylpalladium compounds have been
synthesized, and their reactions with organic substrates
have been thoroughly explored.2 In marked contrast to
† Universidad de La Rioja.
(3) (a) Werner, H. Adv. Organomet. Chem. 1981, 19, 155. (b) Oro,
L. A.; Pinillos, M. T.; Tejel, C.; Foces-Foces, C.; Cano, F. H. J . Chem.
Soc., Dalton Trans. 1986, 1087. (c) Cano, F. H.; Foces-Foces, C.; Oro,
L.; Pinillos, M. T.; Tejel, C. Inorg. Chim. Acta 1987, 128, 75. (d)
Mackenzie, P. B.; Coots, R. J .; Grubbs, R. H. Organometallics 1989, 8,
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Tiripicchio-Camellini, M. J . Chem. Soc., Dalton Trans. 1991, 255. (f)
Braunstein, P.; Knorr, M.; Piana, H.; Schubert, U. Organometallics
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Chem. 1991, 30, 524. (h) Sawamura, M.; Nagata, H.; Sakamoto, H.;
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1980, 18, 207. (b) Roberts, D. A.; Geoffroy, G. L. In ref. 1c, vol. 6,
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Falvello, l.; Fornie´s, J .; Lalinde, E.; Toma´s, M. Organometallics 1993,
12,6. (c) Fornie´s, J .; Lalinde, E.; Mart´ın, A.; Moreno, M. T.; J . Chem.
Soc., Dalton Trans. 1994, 135. (d) Berenguer, J . R.; Fornie´s, J .; Lalinde,
E.; Mart´ın, A.; Moreno, M. T. J . Chem. Soc., Dalton Trans. 1994, 3343.
(e) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.; Mart´ın, A. Angew. Chem.,
Int. Ed. Engl. 1994, 33, 2083. (f) Berenguer, J . R.; Fornie´s, J .; Mart´ınez,
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1993, 12, 1797. (g) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.; Mart´ınez,
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510, 63.
‡ Universidad de Zaragoza-Consejo Superior de Investigaciones
Cient´ıficas.
X Abstract published in Advance ACS Abstracts, September 15, 1996.
(1) For useful reviews see: (a) Tsuji, J .; Minami, I. Acc. Chem. Res.
1987, 20, 140. (b) Heck, R. F. Palladium Reagents in Organic Synthesis;
Academic Press: New York, 1985, Chapter 5. (c) Trost, B. M.;
Verhoeven, T. R. Comprehensive Organometallic Chemistry; Wilkinson,
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1982; vol. 8, chapter 57. (d) Consiglio, G.; Waymouth, R. M. Chem.
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S0276-7333(96)00332-9 CCC: $12.00 © 1996 American Chemical Society

4538 Organometallics, Vol. 15, No. 21, 1996
Berenguer et al.
could be the formation of the less polar end complexes.5a
Thus, in the reaction of [cis-M(C6F5)2(THF)2] and neu-
tral [cis-PtL2(CtCR)2] alkynylation was not observed
but complexation gave symmetrical doubly alkynyl
bridged complexes (Scheme 1b)5a and, interestingly, the
reaction of the “cis-Pt(C6F5)2” fragment with the bi-
nuclear dianionic [(RCtC)2Pt(µ-η1:η2-(CtCR)Pt(C6F5)2-
(µ-η1:η2-CtCR)]2- derivatives gave no alkynylation
product but rather π-complexation yielding trimetallic
compounds with the simultaneous presence of both
symmetrical and unsymmetrical doubly alkynyl bridg-
ing systems (Scheme 1c).5c In addition the reactions of
[cis-Pt(C6F5)2(CtCR)2]2- and [Pt(CtCR)4]2- with mer-
cury(II) halides gave no alkynylation product but did
give 1:1 (Scheme 1d) or 1:2 π-complexes.5d It was
considered that the anionic nature of these σ bis- and
tetraalkynyl complexes should also render them suf-
ficiently nucleophilic to displace halides from other
metal centers to form heterometallic alkynyl-bridged
complexes. This was indeed the case, and we describe
herein the synthesis and properties of new heterome-
tallic (Pt-Pd) bis(µ-alkynyl) complexes that are derived
from [cis-PtX2(CtCR)2]n- [X ) C6F5 or CtCR, n ) 2; X
) PPh3, n ) 0] σ-alkynyl derivatives and the (η3-allyl)
palladium chloride dimer. To the best of our knowledge
these are the first examples in which the cationic Pd-
(η3-allyl)+ unit is attached to η2-alkyne functions. A
preliminary account of this work has been published.10
Sch em e 1
others6 have prepared homo and hetero dinuclear
doubly alkynyl bridged compounds by reacting σ-bis-
(alkynyl) complexes with a second complex which has
either open coordination sites or other ligands which can
be easily displaced by the alkynyl group. More recently
bimetallic doubly alkynyl bridged complexes have also
been prepared by the cleavage of alkynes and butadiynes
induced by metallocene complexes.7
We have previously described the preparation of
mixed [cis-Pt(C6F5)2(CtCR)2]2- 8 and homoleptic [Pt-
(CtCR)4]2- 9 σ-alkynyl anionic species and have shown
that they act as monoalkynylating agents in the reaction
with the neutral [cis-M(C6F5)2(THF)2] (M ) Pd, Pt)
yielding binuclear complexes5a,c (Scheme 1a) in which
the metal centers are asymmetric bridged by two
alkynyl ligands. Later we were able to show that [cis-
Pt(C6F5)2(CtCPh)2]2- reacts with the solvent complex
[IrCp*(PEt3)(Me2CO)2](ClO4)2 via a double alkynylation
process to yield [Cp*(PEt3)Ir(µ-η1:η2-CtCPh)2Pt(C6F5)2]5g
in which the alkynyl groups are σ-bonded to the iridium
center and π-bonded to the platinum one (Scheme 1b).
Although the driving force for these alkynyl transfer
processes is not clear, we assume that one of the reasons
Resu lts a n d Discu ssion
The results of reactions starting from {[Pd(η3-C3H5)-
Cl]2} are summarized in Scheme 2. As reported previ-
ously10 homo- and heterobimetallic anionic symmetrical
doubly acetylide bridged complexes (NBu4)[cis-(C6F5)2-
Pt(µ-η1:η2-CtCSiMe3)2M(C3H5)] (M ) Pt, Pd 1c) can be
easily prepared by reacting (NBu4)2[cis-Pt(C6F5)2(CtC-
SiMe3)2] with {[M(C3H5)Cl]n} (M ) Pt, n ) 4; M ) Pd,
n ) 2) in acetone and in a 4:1 molar ratio for M ) Pt or
2:1 for M ) Pd. The structure of 1c was established by
X-ray crystallography and revealed that the resulting
anion is highly polar, in fact, it is formally zwitterionic,
formed by a dianionic “{cis-Pt(C6F5)2(CtCSiMe3)2}2-
”
fragment which acts as a chelating diyne ligand to the
cationic “{Pd(η3-C3H5)}+” unit. A view of the anion and
details of the crystallographic study are available in ref
10 and will not be repeated here. The formation of
complexes (1a -c) is noteworthy since a less-polar anion
(with one alkynyl σ-bonded to each metal) could have
been expected from an alkynylation process. We found
that the analogous heterobinuclear phenyl and tert-
butyl acetylide species 1a ,b can be similarly obtained
starting from the corresponding [cis-Pt(C6F5)2(CtCR)2]2-
(6) (a) Erker, G.; Fro¨mberg, W.; Benn, R.; Mynott, R.; Angermund,
K.; Kru¨ger, C. Organometallics 1989, 8, 911. (b) Yasufuku, K.;
Yamazaki, H. Bull. Chem. Soc. J pn. 1972, 45, 2664. (c) Ciriano, M.;
Howard, J . A. K.; Spencer, J . L.; Stone, F. G. A.; Wadepohl, H. J . Chem.
Soc., Dalton Trans. 1979, 1749. (d) Lang, H.; Herres, M.; Zsolnai, L.
Organometallics 1993, 12, 5008. (e) J anssen, M. D.; Herres, M.; Zsolnai,
L.; Grove, D, M.; Spek, A. L.; Lang, H.; Van Koten, G. Organometallics
1995, 14, 1098. (f) J anssen, M. D.; Herres, M.; Spek, A. L.; Grove, D.
M.; Lang, H.; Van Koten, G. J . Chem. Soc., Chem. Commun. 1995,
925. (g) Lang, H.; Herres, M.; Imohof, W. J . Organomet. Chem. 1994,
464, 283. (h) Lang, H.; Blau, S.; Nuber, B.; Zsolnai, L. Organometallics
1995, 14, 3216 and refs given therein. (i) Lang, H.; Ko¨hler, K.; Bu¨chner,
M. Chem. Ber. 1995, 128, 525. (j) Lotz, S.; Van Rooyen, P. H.; Meyer,
R. Adv. Organomet. Chem 1995, 37, 219 and ref. therein. (k) Lang,
H.; Ko¨hler, K.; Blau, S. Coord. Chem. Rev. 1995, 143, 113 and refs
therein.
(7) (a) Troyanov, S. I.; Varga, V.; Mach, K. Organometallics 1993,
12, 2820. (b) Varga, V; Mach, K.; Hiller, J .; Thewalt, M.; Sedmera, P.;
Pola´sek, M. Organometallics 1995, 14, 1410. (c) Rosenthal, U.; Uhff,
A.; Baumann, W.; Kempe, R.; Tillack, A.; Burlakov, V. V. Organome-
tallics 1994, 13, 2903. (d) Rosenthal, U.; Pulst, S.; Arndt, P.; Ohff, A.;
Tillack, A. Baumann, W.; Kempe, R.; Burlakov, V. V. Organometallics
1995, 14, 2961 and refs therein. (e) Pulst, S.; Arndt, P.; Baumann, W.;
Tillack, A.; Kempe, R.; Rosenthal, U. J . Chem. Soc., Chem. Commun.
1995, 1753.
t
(R ) Ph or Bu) complexes. However, the same reac-
tions with {[Pt(C3H5)Cl]4} did not allow the preparation
of any stable homobimetallic compounds. Data char-
acterizing the new 1a ,b complexes, as well as low
temperature NMR data for complex 1c, are given in the
Experimental Section. Thus, the presence of bridging
alkynyl ligands can be easily inferred from the observa-
tion, in their IR spectra, of a ν(CtC) absorption (2016
cm-1 1a ; 2015 cm-1 1b) at lower frequencies than those
observed for the mononuclear [cis-Pt(C6F5)2(CtCR)2]2-
(8) Espinet, P.; Fornie´s, J .; Mart´ınez, F.; Sote´s, M.; Lalinde, E.;
Moreno, M. T.; Ruiz, A.; Welch, A. J . J . Organomet. Chem. 1991, 403,
253.
[R ) Ph 2095, 2082 cm-1; R ) tBu 2085, 2090(sh) cm-1
]
(9) Espinet, P.; Fornie´s, J .; Mart´ınez, F.; Toma´s, M.; Lalinde, E.;
Moreno, M. T.; Ruiz, A.; Welch, A. J . J . Chem. Soc., Dalton Trans.
1990, 791.
(10) Berenguer, J . R.; Fornie´s, J .; Lalinde, J .; Mart´ınez, F. J .
Organomet. Chem. 1994, 470, C15.

Reactions of (σ-Alkynyl)platinum Complexes
Organometallics, Vol. 15, No. 21, 1996 4539
Sch em e 2a
a
(i) + 2Q2[cis-Pt(C6F5)2(CtCR)2]; (ii) + 2(NBu4)2[Pt(CtCR)4]; (iii) + (NBu4)2[Pt(CtCR)4]; (iv) + 2[cis-Pt(CtCR)2(PPh3)2] + NaClO4
(excess).
precursors and in the range expected for CtC triple
Hz) and δ ) 110.13 (Câ, 2J Pt-C ) 293.4 Hz); R ) SiMe3,
δ ) 140.7 (CR, 1J Pt-C ) 997 Hz) and δ ) 104.0 (Câ, 2J Pt-C
) 270.7 Hz)].
bond side-on coordinated to a transition metal.5-7 In
1
the H NMR spectrum of 1a the methylene hydrogen
The 19F NMR spectra of complexes 1a and 1b (and
also 1c)10 exhibit, at room temperature, a set of three
signals only which are those of the o-, p-, and m-fluorine
atoms, showing that as expected both C6F5 groups are
equivalent. The bent shape of the Pt(acetylide)2Pd core
found for complex 1c should, however, give rise to
inequivalence of the o-fluorine atoms (and the m-
fluorine atoms as well) on each C6F5 ligand. The
presence of only one type of o-F and m-F, which appear
as sharp resonances, indicates an effective equivalence
of these atoms and suggests that the complexes are not
rigid in solution. The simplicity of the spectra (at room
temperature) can be tentatively explained either by
assuming a rapid rotation of C6F5 rings around the Pt-
ipso-C(C6F5) bonds12 or a rapid intramolecular exchange
of the [Pd(allyl)]+ unit below and above the platinum
coordination plane. At -50 °C, the 19F NMR spectra of
complexes 1 reveal the same sharp pattern as at room
temperature, indicating that the dynamic process is very
rapid even at low temperature.
atoms of the allyl group give rise to two doublet
resonances (δ 3.4 and 4.0) while the methine hydrogen
appears as a multiplet at δ 5.5. The two doublet signals
are assigned11 to the anti- and syn-protons (Hanti and
Hsyn), respectively, since the doublet separation of the
former J anti ) 12.2 Hz (due to coupling with the central
proton) is larger than that of the latter [J syn ) 6.7 Hz].11
In the tert-butyl acetylide complex 1b, although the
resonances due to syn-protons [δ 4.43 (d); J syn ) 6.5 Hz]
and methine hydrogen [δ 5.3(m)] of the allyl group are
clearly visible, the resonance due to the anti-protons
overlaps (δ 3.06) with one of the signals which is
+
characteristic of the NBu4 cation. The tert-butyl
groups of the alkynyl ligands give rise to a singlet
resonance at δ 1.15, as expected. We noted that no
evidence of allyl group rotamers was detected by record-
ing the 1H NMR spectra of complexes 1a -c at low
temperature (-50 °C, see Experimental Section). Like-
wise, the 13C{1H} NMR spectra of 1b and 1c at low
temperature (-50 °C) display two allyl signals (CH and
CH2) due to the presence of only one η3-C3H5 ligand. It
has been previously observed6a,h that π-complexation of
terminal alkynyl ligands to a second metal center
results in a downfield shift of the CR and Câ 13C NMR
resonances. It is noteworthy that in the dimeric com-
plexes 1b and 1c such deshielding signals are not
observed. The alkyne carbon resonances CR and Câ are
observed at δ 80.5 (1J Pt-C ) 820.2 Hz) and at δ 106.4
(2J Pt-C ) 281.7 Hz) for 1b and at δ 117.6 and at δ 94.2
for 1c which are, in fact, slightly shifted to highfield
compared to data for the parent complexes (NBu4)2[Pt-
(C6F5)2(CtCR)2] [R ) tBu, δ ) 98.2 (CR, 1J Pt-C ) 1048.2
The easy bridge splitting and displacement of the
chloride ligands of the (η3-allyl)palladium dimer allows
the synthesis of anionic (Pt-Pd, 2a -c) or neutral (Pd-
Pt-Pd, 3a -c) tetraalkynyl-allyl compounds by reaction
with the corresponding anions [Pt(CtCR)4]2- at a 1:2
(Scheme 2, ii) or 1:1 (Scheme 2, iii) molar ratio,
respectively. The reaction between (NBu4)2[Pt(CtCR)4]‚
t
2H2O (R ) Bu or SiMe3) and {[Pd(η3-C3H5)Cl]2} (2:1
molar ratio) in acetone affords deep yellow solutions
(slightly dark for R ) SiMe3) from which the binuclear
anionic derivatives (NBu4)[(CtCR)2Pt(µ-CtCR)2Pd(η3-
t
C3H5)] (R ) Bu 2b or SiMe3 2c) can be isolated as
yellow solids (2b 34%, 2c 85%). However, the analogous
(11) The assignments of allyl protons resonances in all complexes
was made following the usual criteria: (a) Grassi, M.; Meille, S. V.;
Musco, A.; Potellini, R.; Sironi, A. J . Chem. Soc., Dalton Trans. 1989,
615 and refs therein. (b) see also ref 2a.
(12) Casares, J . A.; Coco, S.; Espinet, P.; Lin, Y. S. Organometallics
1995, 14, 3058.

4540 Organometallics, Vol. 15, No. 21, 1996
Berenguer et al.
Sch em e 3
reactions of (NBu4)2[Pt(CtCPh)4] with {[Pd(η3-C3H5)-
Cl]2} (2:1 molar ratio) lead to a mixture of the analogous
anionic derivative 2a and the corresponding trinuclear
neutral compound 3a . Complex {Pt(CtCPh)4[Pd(η3-
C3H5)]2} 3a (yield 9%) precipitates as a yellow solid
during the reaction time, and the evaporation of the
filtrate to dryness and subsequent treatment with cold
EtOH affords the binuclear anionic complex 2a although
in a very low yield (11%). Complex 3a precipitates in
very high yield (78%) by the addition of 1 equiv of
[Pt(CtCPh)]2- to {[Pd(η3-C3H5)Cl]2} in acetone (Scheme
2, iii). Similarly, treatment of {[Pd(η3-C3H5)Cl]2} with
previously in the binuclear complexes (NBu4)2[(C6F5)2-
Pt(µ-CtCR)2Pt(CtCR)2] (R ) tBu, SiMe3).5c However,
1
while the H NMR spectrum of 2b remains essentially
unchanged in the temperature range (15 °C to -50 °C),
the singlet resonance caused by the SiMe3 groups in
complex 2c is split into two different signals (δ 0.05 and
0.002) at -10 °C which is consistent with the presence
of terminal and bridging alkynyl ligands according to
the structure proposed in Scheme 2. The observed
equivalence of terminal and bridging alkynyl ligands at
low temperature for complex 2b could be due to an
accidental coincidence of signals. The low temperature
(-50 °C) 13C NMR spectra of both complexes (2b and
2c) show, in the high field region, apart from the reso-
t
1 equiv of [Pt(CtCR)4]2- (R ) Bu, SiMe3) in acetone
affords the trinuclear complexes 3b and 3c, respectively,
in moderate yield (3b 60%, 3c 40%). Complexes 2 and
3 are moderately stable in the solid state, but their
solutions (acetone, CH2Cl2 or CHCl3) darken in 1 or 2
h. For complexes 2, no X-ray quality crystals have been
obtained, but analytical, conductivity measurements,
and spectroscopic data are consistent with structures
shown in Scheme 2. Thus, the conductivities of com-
plexes 2 in acetone solutions are those expected for 1:1
electrolytes.13 The most remarkable feature in the IR
spectra of compounds of type 2 is the presence of one
(2026 cm-1 2a ; 2020 cm-1 2b) or two bands (1953 and
1938 cm-1 2c) which are considerably shifted to lower
wavenumbers compared to those of the σ-alkynyl pre-
cursor (2075 cm-1 R ) Ph, 2081cm-1 R ) tBu, 2015 cm-1
R ) SiMe3) which can be attributed to the Pt(µ-CtCR)2-
Pd moiety. Furthermore, they also show additional ν-
(CtC) absorptions at higher frequencies [2098(vs, sh)
cm-1 2a ; 2095(s) cm-1 2b; 2042(vs) and 2027(vs) cm-1
2c] which is in line with the presence of terminal
alkynyl groups.14 Similar IR patterns have been ob-
served in CH2Cl2 solution suggesting that the η2-
alkynyl-Pd interactions remain in this solvent. In
contrast, the IR spectra of complexes 3 show only one
strong absorption in the region 2023-1954 cm-1 (with
a shoulder at 1919 cm-1 for complex 3c) indicating that
all CtCR groups are acting as bridging ligands.
+
nances due to the NBu4 cation, the presence of two
magnetically inequivalent tert-butyl (δ 32.9, 32.5 C(CH3)3
and 29.7, 29.0 CMe3) or trimethylsilyl groups (δ 1.42,
1.37), indicating the presence of terminal and bridging
alkynyl ligands. As expected, in the low-field region
both complexes reveal, in addition to the singlet reso-
nance due to CH2 groups of the allyl ligand, five signals
which can be attributed to four alkynyl carbon atoms
and to the central carbon atom of the η2-C3H5 group.
The absence of platinum satellites in the alkynyl carbon
resonances for 2b precludes a proper assignment. How-
ever, in complex 2c the CR and Câ alkynyl carbons
appear at δ 130.5 and 119.2 and at δ 106.2 and 93.9,
respectively, and are easily assigned since the former
show larger coupling constants to 195Pt nuclei (990.3 and
724.2 Hz) than the latter (267 and 244.8 Hz). The
downfield resonance (δ 130.5) and the signal at δ 106.2
are tentatively assigned to the CR and Câ of terminal
alkynyl ligands since both the chemical shifts and the
1J Pt-C coupling constant are similar to those observed
in the starting material [Pt(CtCSiMe3)4]2- (δ 140.4, CR,
2
1J Pt-C ) 924 Hz and δ 104.4, Câ, J Pt-C ) 250.4 Hz).
Assignment of the resonances at 119.2 and 93.9 to the
CR and the Câ of bridging alkynyl ligands is consistent
with the slight highfield shifts and the decrease in the
magnitude of 1J Pt-CR observed in the dimeric complexes
1b and 1c.
The 1H NMR spectrum of complex 2a shows the
expected resonances for the allyl group (5.46 m, CH;
3.88 d, Hsyn; 3.28 d, Hanti) besides the resonances of the
For the trinuclear derivatives 3, unambiguous struc-
tural assignment also failed due to the fact the all our
attempts to obtain suitable crystals for the X-ray
analysis of these complexes were unsuccessful. If it is
assumed that the trimetallic species 3 are only 1:2
π-adducts, and if the less favorable situations with the
allyl groups located on the same side of the platinum
coordination plane are excluded, there should be three
isomers for these derivatives, I-III, shown in Scheme
3.
+
1
aromatic protons and the NBu4 cation. The H NMR
spectra of complexes 2b and 2c at room temperature
exhibit the expected resonances for one allyl group but
t
only one type of alkynyl ligand (δ 1.17 Bu 2b; 0.05
SiMe3 2c), suggesting dynamic behavior that probably
involves a rapid “Pd(η3-allyl)” unit exchange on the
NMR time-scale between bridging and terminal alkynyl
groups. A similar phenomenon has been observed
1
The room and low temperature H NMR spectra of
(13) Geary, W. J . Coord. Chem. Rev. 1971, 7, 81.
(14) Nast, R. Coord. Chem. Rev. 1982, 47, 89.
the tert-butyl derivative 3b exhibit the allyl proton

Reactions of (σ-Alkynyl)platinum Complexes
Organometallics, Vol. 15, No. 21, 1996 4541
F igu r e 1. 1H NMR spectra of complex 3c at different temperatures (allyl region).
signals of equivalent allyl groups with well separated
doublet resonances for the anti (rt δ 2.95) and syn (rt δ
a
4.46) protons. A singlet at δ ) 1.16 in 3b indicates that
at least in solution all alkynyl groups are also equiva-
lent. In the 13C NMR spectrum of 3b at low tempera-
ture (-50 °C) the expected four and two signals due to
equivalent alkynyl (CtCCMe3) and allyl (CH and CH2)
groups are observed. The CR (δ 73.4, 1J Pt-C ) 906.5 Hz)
2
and Câ (δ 107.4, J Pt-C ) 297.3 Hz) carbon resonances
are again shifted to highfield compared to those ob-
served in the starting material (δ 98.9, CR, 1J Pt-C ) 975
2
Hz; δ 108.4, Câ, J Pt-C ) 279 Hz). Although the
simplicity of the spectra could be attributed to the
presence of only one isomer (II or III), a rapid equilib-
b
rium of isomers (including I) cannot be excluded.
1
Thus, the H NMR spectra of complexes 3a and 3c
(see Figure 1 for complex 3c) are very similar and
temperature dependent. At high temperature (50 °C
for 3c, 30 °C for 3a ) they show, in addition to the
methine signal as a multiplet, sharp and well separated
doublet resonances only for the anti (δ 3.09 3c; δ 3.39
3a ) and syn (δ 4.54 3c; δ 3.93 3a ) protons showing that
F igu r e 2. Lowfield region of the 13C NMR spectra of: (a)
both allyl groups are equivalent. The trimethylsilyl
groups in 3c give rise to a sharp singlet (δ 0.14). Both,
the anti and syn proton signals broaden (see Figure 1
for complex 3c) when the system is cooled and finally
resolved into a pair of doublets (the two Hsyn doublets
overlap giving an apparent triplet in 3c) of similar ratio
(ca. 1.16:1 for 3a and 1:1.4 for 3c), indicating the
presence of two magnetically inequivalent allyl groups.
For complex 3c, the signal due to SiMe3 groups is also
split at -50 °C into two signals of different intensity
but their proximity (δ 0.01 and 0.09) precludes proper
integration.
complex 3c at -50 °C. (b) (NBu4)2[Pt(CtCSiMe3)4]‚2H2O
at 15 °C (J in Hz).
units to the palladium center, the alkyne carbon signals
in the starting [Pt(CtCSiMe3)4]2- precursor (Figure 2b)
shift highfield, a characteristic which is typical of these
heteronuclear platinum-palladium complexes. The
more extended low field shift of the CR resonances in
the trimethylsilyl derivatives compared to the tert-butyl-
alkynyl complexes, both in the starting precusors and
in the 1-3 complexes, can be attributed to the â-Si-effect
of the SiMe3 group, which produces a partial positiva-
tion of the inner CR carbon atom of the alkynyl ligand.7c
As can be observed in Figure 2a, the intensity of the
signals clearly suggests different ratios for the two
magnetically inequivalent allyl and alkynyl ligands, in
keeping with the low-temperature proton NMR spec-
Likewise, the 13C NMR spectrum of 3c at low tem-
perature (-50 °C) also exhibits the presence of two
inequivalent allyl and trimethylsilylalkynyl ligands. The
lowfield part of this spectrum showing the alkynyl (CR
and Câ) and methine carbon resonances is given in
Figure 2a. Due to the η2-coordination of the Me3SiCtC

4542 Organometallics, Vol. 15, No. 21, 1996
Berenguer et al.
trum. This fact is not consistent with isomer I and could
be tentatively attributed to the presence of a mixture
of isomers II and III, whose rate of interconversion is
slow at low temperature on the NMR time-scale.
The fluxional behavior of allylpalladium complexes
has been thoroughly studied15 and we have little new
to add. There are a number of possible mechanisms for
isomerization, including simple π-allyl rotation of the
Pd(allyl) units, with or without Pd-alkyne breaking and
simultaneous or sequential inversion of the central PtC4-
Pd puckered cores via intermediate species with one or
both alkynyl ligands symmetrically (η1) bridging the two
metal centers.5a,b Isomerization pathways involving
intermolecular reactions via five-coordinated species can
also be considered. A η3-η1-η3 movement of the allyl
groups at high temperature have to be excluded since
no averaging of the syn and anti protons of the allyl
groups is observed.
Finally, as a part of this study, the reactions of {[Pd-
(η3-allyl)Cl]2} with neutral bis-alkynyl platinum deriva-
tives were also examined. Treatment of an acetone
solution of the π-allyl palladium chloride dimer with 2
equiv of [cis-Pt(CtCR)2(PPh3)2] (R ) Ph, tBu) and with
an excess of NaClO4 leads to the corresponding cationic
heterobimetallic complexes [cis-(PPh3)2Pt(µ-η1:η2-CtCR)-
Pd(η3-C3H5)][ClO4] (R ) Ph 4a ; tBu 4b), consistent with
Scheme 2 (iv), which were isolated as white (4a ) and
pale yellow (4b) solids in good yields. The IR spectrum
of 4b in Nujol mulls shows two weak ν(CtC) bands at
2040 and 2020 cm-1 together with the typical absorption
of uncoordinated perchlorate at 1095 and 623 cm-1 16
.
Furthermore, consistent with the mutually cis disposi-
tion of the two PPh3 ligands,17 the spectrum shows four
bands at 544, 528, 516, and 501 cm-1. Unfortunately,
it was not possible to form an emulsion with Nujol for
complex 4a , and the expected absorption due to ν(CtC)
was not observed in CH2Cl2 solution.
The low temperature NMR spectra of both complexes
are very simple. The 31P NMR spectra show a singlet
with platinum satellites in keeping with the cis disposi-
tion of the PPh3 ligands, and in the 1H NMR spectra
the characteristic signals of only one η3-allyl moiety,
with separated resonances for syn and anti protons, are
observed. These spectroscopic data suggest the pres-
ence of only one isomer or alternatively that a very fast
equilibration between both rotamers (exo and endo) is
possible. Complex 4b crystallizes (see below), adopting
F igu r e 3. (a) Structure of the cation [cis-(PPh3)2Pt(µ-η1:
η2-CtCtBu)2Pd(η3-C3H5)]+ 4b with the atomic numbering
scheme. (b) Sandwiched view of the cation 4b showing the
π-interactions around the Pd atom.
probably the less hindered endo relationship with the
terminal allylic protons in a trans disposition to the
t
bulky Bu groups of the alkynyl ligands. Complex 4b
reveals similar spectra at room and high (50 °C)
temperature. For 4a , only a partial overlap of the
resonances due to syn and anti protons was observed
at room and high temperature. As expected, in the 13C
NMR spectra at low temperature (-50 °C) both the CR
(δ 84.7 4a ; δ 75.6 4b) and Câ (δ 102.8 4a ; δ 112.5 4b)
alkynyl bridging carbon resonances appear again to be
shifted highfield with respect to those observed in the
starting complexes [cis-Pt(CtCR)2(PPh3)2] [R ) Ph, δ
102.6 (CR), 109.8 (Câ); R ) tBu, δ 85.8 (CR), 117.1 (Câ)].
The structure of 4b has been determined by X-ray
diffraction. A view of the complex cation [cis-(PPh3)2-
Pt(µ-η1:η2-CtCtBu)2Pd(η3-C3H5)]+ is given in Figure 3a.
Selected bond distances and angles are collected in
Table 1. The structure is similar to that of the anion
in compound 1c,10 in which the Pd(η3-allyl) unit is
coordinated to the bis(alkynyl)platinum fragment through
an η2-side-on coordination of the two alkynyl ligands.
(15) For general reviews of allyl isomerization mechanism see: (a)
Vrieze, K. In Dynamic Nuclear Magnetic Resonance Spectroscopy;
J ackman, L. M., Cotton, F. A., Eds.; Academic Press: New York, 1975;
pp 441-487. (b) Mann, B. F. in ref 1c, vol. 3, chapter 20 and references
therein. For more recent work see: (c) Albinati, A.; Kunz, R. W.;
Ammann, C. J .; Pregosin, P. S. Organometallics 1991, 10, 1800. (d)
Grascall, L. E.; Spencer, J . L. J . Chem. Soc., Dalton Trans. 1992, 3445.
(e) Hampton, P. D.; Wu, S.; Alam, T. M.; Claverie, J . P. Organometallics
1994, 13, 2066. (f) Gogoll, A.; O¨ rnebro, J .; Grennberg, H.; Ba¨ckwall, J .
E. J . Am. Chem. Soc. 1994, 116, 3631 and refs therein. (g) De Munno,
G.; Bruno, G.; Rotondo, E.; Giordano, G.; Lo Schiavo, S.; Piraino, P.;
Tresoldi, G. Inorg. Chim. Acta 1993, 208, 67. (h) Hansson, S.; Norrby,
P. O.; Sjo¨gren, M. P. T.; Akermark, B.; Cucciolito, M. E.; Giordiano,
F.; Vitagliano, A. Organometallics 1993, 12, 4940. (i) J alo´n, F. A.;
Manzano, B. R.; Otero, A.; Rodr´ıguez-Pe´rez, M. C. J . Organomet. Chem.
1995, 494, 179. (j) Herrmann, J .; Pregosin, P. S.; Salzmann, R.;
Albinati, A. Organometallics 1995, 14, 3311. (k) Cesaroti, E.: Grassi,
M.; Prati, L. J . Chem. Soc., Dalton Trans. 1989, 161.
(16) Nakamoto, K. Infrared and Raman Spectra of Inorganic and
Coordination Compounds, 4th ed.; Wiley Interscience: New York, 1986;
p 138.
(17) (a) Mastin, S. H. Inorg. Chem. 1974, 13, 1003. (b) Furlani, A.;
Licoccia, S.; Russo, M. V.; Villa, A. Ch.; Guastini, C. J . Chem. Soc.,
Dalton Trans. 1984, 2197.

Reactions of (σ-Alkynyl)platinum Complexes
Organometallics, Vol. 15, No. 21, 1996 4543
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 4b
P2)] with similar Pt-P [2.305(3) and 2.303(4) Å] and
Pt-C(alkynyl) distances [2.019(14) and 2.032(15) Å] to
those reported in the literature on related bonds.5a,g,19
Pt(1)-Pd(1)
Pt(1)-P(2)
Pt(1)-C(7)
Pd(1)-C(2)
Pd(1)-C(8)
Pd(1)-C(50)
C(1)-C(2)
3.026 (1)
2.305 (3)
Pt(1)-P(1)
Pt(1)-C(1)
Pd(1)-C(1)
Pd(1)-C(7)
Pd(1)-C(49)
Pd(1)-C(51)
C(2)-C(3)
2.303 (4)
2.032 (15)
2.245 (14)
2.286 (13)
2.130 (22)
2.159 (22)
1.467 (26)
1.496 (23)
1.366 (39)
Finally, the bond lengths and angles of the acetylene
skeletons are very similar to those found in the anion
1c.10 The PtsCRtCâ fragments are not very distorted
[171.5(12)° and 174.0(13)°] in cation 4b, whereas they
are distinctly bent in 1c (average 167.65(16)°], but the
bending-back angles at Câ [167.4(16) and 165.2(16)° in
4b versus 167.4(17) and 165.5(18)° in 1c] are practically
the same. The CtC bond lengths in 4b [1.187(20) Å
and 1.213(22) Å] and in 1c [1.201(25) Å and 1.238(27)
Å] are identical within experimental error.
2.019 (14)
2.439 (15)
2.487 (15)
2.118 (26)
1.213 (22)
1.187 (20)
1.396 (48)
C(7)-C(8)
C(8)-C(9)
C(49)-C(50)
C(50)-C(51)
Pd(1)-Pt(1)-P(1)
P(1)-Pt(1)-P(2)
P(1)-Pt(1)-C(7)
C(1)-Pd(1)-C(7)
C(7)-Pd(1)-C(49)
C(1)-Pd(1)-C(51)
C(49)-Pd(1)-C(51)
Pt(1)-C(1)-C(2)
Pt(1)-C(7)-Pd(1)
C(7)-C(8)-C(9)
125.2(1)
101.4(1)
91.2(4)
71.2(5)
105.8(9)
108.8(7)
67.5(10) Pt(1)-C(1)-Pd(1)
174.0(13) C(1)-C(2)-C(3)
89.1(5)
Pd(1)-Pt(1)-P(2)
P(2)-Pt(1)-C(1)
C(1)-Pt(1)-C(7)
C(2)-Pd(1)-C(8)
C(8)-Pd(1)-C(49)
C(2)-Pd(1)-C(51)
122.3(1)
86.2(4)
81.3(6)
108.1(5)
91.0(9)
92.9(7)
89.9(5)
165.2(16)
171.5(12)
It should be noted that in contrast with other well
known heterometallic tweezer like complexes [M]-
(CtCR)2M′Ln which display almost planar MC4M′
cores,6f-i,k the palladium atom is not embedded by the
bis-alkynyl platinum fragment but sandwiched between
the acetylenic fragments and the allyl moiety (see
Figure 3b), thus resulting in a central nonplanar
PtC7C8C1C2Pd core. A similar structural feature has
been found in the anion 1c,10 {[Pt(dppe)(CtCPh)2]Pt-
(C6F5)2}5a and [Cp*(PEt3)Ir(CtCPh)2Pt(C6F5)2],5g but
Pt(1)-C(7)-C(8)
167.4(16) C(49)-C(50)-C(51) 119.2(24)
The most remarkable difference is that the η2-pal-
ladium-alkynide linkages are clearly asymmetric in 4b,
the Pd-CR distances [Pd-C7 2.286(13) Å; Pd-C1 2.245-
(14) Å] being shorter than the corresponding Pd-Câ
ones [Pd-C8 2.487(15) Å; Pd-C2 2.439(15) Å] and
contrasting with the symmetrical η2-linkages found in
the anion 1c and in {[cis-(dppe)Pt(µ-CtCR)2]Pt(C6F5)2}.5a
It should be noted that this type of asymmetry, previ-
ously observed in platinum-silver alkynyl compounds,18
contrast with the asymmetry found in the anion {[cis-
Pt(C6F5)2(µ-CtCSiMe3)2]HgBr2}5d with shorter Hg-Câ
than Hg-CR distances. As expected, the distance
between the platinum and palladium atoms is slightly
shorter in the cation 4b [3.026(1) Å] than in the
binuclear anion 1c [3.049(2)],10 but this does not imply
a Pt-Pd bonding interaction.
5d
{[cis-Pt(µ-CtCSiMe3)2(C6F5)2]HgBr2]2 displays a pla-
nar Pt-C4-Hg core. Interestingly, in the trinuclear
cation {[cis-(PPh3)2Pt(µ-CtCPh)2]2Ag} the silver atom
is only well embedded by one of the two bis-alkynyl
platinum fragments.5h It is probable that steric effects
are responsible for this structural feature. For square-
planar coordination of the monomeric M′Ln building
block, a tweezer effect of the alkynyl substituents would
be more sterically hindered.
Con clu d in g Rem a r k s
Apart from the above considerations, all the other
bond distances and angles in the cation are within the
expected range. Thus, the geometry around the pal-
ladium atom is similar to that observed in the anion 1c
and in other Pd-allyl complexes.2a,c,g,3b,11a,15c,g,h,j In
particular, the allyl group is symmetrically bound [Pd-
C49 ) 2.130(22); Pd-C51 ) 2.159(22)] and forms a
dihedral angle of 118.44° with the plane defined by the
Pd atom and the midpoints of the CtC triple bonds,
close to the typical value found in η3-allyl Pd and Pt
complexes (110°).2a The acetylenic fragments are coor-
dinated almost perpendicularly to the palladium coor-
dination plane as would be expected from the geometry
of Pd(II)-alkyne: (i) the angles formed by the CtC
triple bonds and the corresponding vectors defined by
Pd and the midpoints of the CtC bonds are 80.5(26)°
(C1-C2) and 79.9(21)° (C7-C8) respectively, and (ii) the
triple bonds are inclined by 35.9(11)° (C1-C2) and 38.4-
(11)° (C7-C8) with respect to the normal to the
C49PdC51 plane.
Palladium(II) forms a very rich chemistry involving
the allyl ligand, and in addition exhibits potential for
access to unusual molecules arising from reactions with
alkynes. It is generally accepted that the first step in
the palladium(II) catalyzed polymerization of alkynes,
as well as in the insertion of an alkyne into a Pd-C
bond, is the formation of a complex in which the alkyne
is η2-coordinated to the metal center.20 However, only
a few of these proposed alkyne coordination complexes
have been reported,5a,21 and none have been character-
ized by X-ray diffraction. Due to the analogy of alkynes
and metallo acetylides (MCtCR) and the peculiar
ability of the anionic [PtX2(CtCR)2]2- (X ) C6F5 or
CtCR) and neutral [cis-Pt(CtCR)2(PPh3)2] substrates
to act as chelate metallodiyne ligands, it has been
possible to isolate, for the first time, several bis-η2-
alkyne Pd(II) complexes containing the very electro-
philic cationic [Pd(allyl)]+ unit.
(19) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.; Mart´ınez, F.; Urrio-
labeitia, E.; Welch, A. J . J . Chem. Soc., Dalton Trans. 1994, 1291.
(20) (a) Maitlis, P. M.; Espinet, P.; Russel, M. J . H. in ref 1c, vol. 6,
chapters 38.5 and 38.9. (b) Maitlis, P. M. Acc. Chem. Res. 1976, 9, 93.
(c) Maitlis, P. M. J . Organomet. Chem. 1980, 200, 161. (d) Huggins, J .
M.; Bergman, R. G. J . Am. Chem. Soc. 1981, 103, 3002. (e) Samsel, E.
G.; Norton, J . R. J . Am. Chem. Soc. 1984, 106, 5505.
On the other hand, in the organometallic platinum
fragment “cis-Pt(PPh3)2(CtCtBu)2”, the Pt atom is in a
slightly distorted square planar environment [angles
ranging from 81.3(6)° (C7-Pt-C8) to 101.4(1)° (P1-Pt-
(18) (a) Fornie´s, J .; Go´mez-Saso, M. A.; Mart´ınez, F.; Lalinde, E.;
Moreno, M. T.; Welch, A. J . New J . Chem. 1992, 16, 483. (b) Fornie´s,
J .; Lalinde, E.; Mart´ınez, F.; Moreno, M. T.; Welch, A. J . J . Organomet.
Chem. 1993, 455, 271. (c) Ara, I.; Fornie´s, J .; Lalinde, E.; Moreno, M.
T.; Toma´s, M. J . Chem. Soc., Dalton Trans. 1994, 2735. (d) Ara, I.;
Fornie´s, J .; Lalinde, E.; Moreno, M. T.; Toma´s, M. J . Chem. Soc., Dalton
Trans. 1995, 2397.
(21) (a) [Pd2Cl4(tBuCtCtBu)2]: Hosokawa, T.; Moritani, I.; Nishioka,
S. Tetrahedron Lett. 1969, 3833. (b) [cis-Pd(C6F5)2(PhCtCPh)2]: Uson,
R.; Fornie´s, J .; Toma´s, M.; Menjo´n, B.; Welch, A. J . J . Organomet.
Chem. 1986, 304, C24. (c) Recently, several palladium(II) complexes
containing η1-metallacarbyne ligands (including X-ray and theoretical
studies) have been reported: Engel, P. F.; Pfeffer, M.; Dedieu, A.
Organometallics 1995, 14, 3423.

4544 Organometallics, Vol. 15, No. 21, 1996
Berenguer et al.
t
Hz); 106.1 (s, CH, allyl); 80.5 (s, CR, -CRtCâ Bu; 1J Pt-C ) 820.2
Hz); 63.1 (s, -CH2, allyl); 57.9 (s, N-CH2-, NBu4); 32.9 (s,
-C(CH3)3); 29.8 (s, -CMe3); 23.2 (s, -CH2-, NBu4); 19.2 (s, -CH2-,
NBu4); 13.4 (s, -CH3, NBu4).
Exp er im en ta l Section
Gen er a l Con sid er a tion s. All the manipulations were
carried out under a nitrogen atmosphere. Acetone was treated
with KMnO4, distilled, and stored over molecular sieves.
Q2[cis-Pt(C6F5)2(CtCR)2] (Q ) PMePh3, R ) Ph; Q ) NBu4,
R ) tBu),8 (NBu4)2[Pt(CtCR)4]‚nH2O) (n ) 0, R ) Ph;9 n ) 2,
The 13C NMR spectrum of the starting complex (NBu 4)2-
[cis-P t(C6F 5)2(CtCtBu )2] in CDCl3 at room temperature (15
°C) was also registered: 149.6 (d), 146.7 (d), 137.6-132.7 (m)
R ) Bu,9 SiMe35c), [cis-Pt(CtCR)2(PPh3)2] (R ) Ph,22 tBu5a),
t
t
(C6F5); 110.1 (s, Câ, -CRtCâ Bu, 2J Pt-C ) 293.4 Hz); 98.2 (s, CR,
and {[Pd(η3-C3H5)Cl]}23 were prepared by published methods.
Proton, 13C, 19F, and 31P NMR spectra were recorded on a
Bruker ARX 300 spectrometer. Chemical shifts are reported
in ppm relative to external standards (Me4Si, CFCl3, and 88%
H3PO4). Infrared spectra were recorded with a Perkin-Elmer
883 spectrometer using Nujol mulls between polyethylene
sheets. C, H, and N analyses were carried out with a Perkin-
Elmer 240C microanalyzer or a Perkin-Elmer 2400 CHNS/O
analyzer. Conductivities were measured in acetone solutions
(ca. 5 × 10-4 mol dm-3) using a Phillips 9501/01 conductimeter.
(P MeP h 3)[cis-(C6F5)2P t(µ-η1:η2-CtCP h )2P d(η3-C3H5)] (1a).
A stirred suspension of (PMePh3)2[cis-Pt(C6F5)2(CtCPh)2] (0.23
g, 0.18 mmol) in 15 mL of acetone was treated with 0.0327 g
(0.09 mmol) of {[Pd(η3-C3H5)Cl]2}, and the reaction mixture
was stirred at room temperature for 10 min. The resulting
deep yellow solution was concentrated to ca. 2 mL, and the
slow addition of EtOH (4 mL) gave a yellow microcrystaline
solid characterized as compound 1a (yield 46%). Anal. Calcd
for C50F10H33PPtPd: C, 51.94; H, 2.87. Found: C, 51.47; H,
2.80. ΛM: 89 Ω-1 cm2 mol-1. IR (cm-1): ν(CtC) 2016 (s with
t
1
-CRtCâ Bu; J Pt-C ) 1048.2 Hz); 58.8 (s, N-CH2-, NBu4); 33.0
(s, -C(CH3)3); 29.5 (s, -CMe3); 24.2 (s, -CH2-, NBu4); 19.6 (s,
-CH2-, NBu4); 13.6(s, -CH3, NBu4).
(NBu 4)[cis-(C6F 5)2P t (µ-η1:η2-CtCSiMe3)2P d (η3-C3H 5)]
(1c).10 1H NMR (CDCl3): at -50 °C, 5.28 (m, CH, allyl); 4.48
(d, 2 Hsyn, J syn ) 5.22 Hz, allyl); 3.06 (m, 10 H, overlapping: 2
H
anti, allyl and 8 H, NCH2-, nBu); 1.49 (br, 8H, -CH2-, nBu);
1.26 (br, 8H, -CH2-, nBu); 0.86 (br, 12H, CH3, nBu); 0.05 (t,
18H, -SiMe3). 19F NMR (CDCl3): at -50 °C: -115.2 (dm, o-F,
3J Pt-o-F ) 397 Hz); -166.4 (m, m-F and p-F). 13C NMR
(CDCl3): at -50 °C 149.1 (m), 146.1 (m), 136.7 (m), 133.8 (m)
(C6F5); 117.6 (s, CR, -CRtCâSiMe3); 107.9 (s, CH, allyl); 94.2
(s, Câ, -CRtCâSiMe3); 65.4 (s, -CH2, allyl); 58.1 (s, N-CH2-,
NBu4); 23.4 (s, -CH2-, NBu4); 19.3 (s, -CH2-, NBu4); 13.5 (s,
-CH3, NBu4); 1.5 (s, SiMe3).
The 13C NMR spectrum of the starting complex (NBu 4)2-
[cis-P t(C6F 5)2(CtCSiMe3)2] in CDCl3 at room temperature
(15 °C) was also registered: 149.3 (d), 146.4 (d), 137.5 -132.9
(m) (C6F5); 140.7 (s, CR, -CRtCâSiMe3, J Pt-C ) 997 Hz); 104.0
(s, Câ, -CRtCâSiMe3; J Pt-C ) 270.7); 58.6 (s, N-CH2-, NBu4);
1
2
+
shoulder); an internal absorption of PMePh3 precludes un-
24.1 (s, -CH2-, NBu4); 19.4 (s, -CH2-, NBu4); 13.5(s, -CH3, NBu4);
2.0 (s, SiMe3).
ambiguous assignment of the x-sensitive modes of C6F5 groups;
three bands at 796 (s), 787 (s), and 775 (s) cm-1 are observed.
1H NMR (CDCl3): at 15°C 7.73, 7.59, 7.19, 7.12 (m, 25H, Ph);
5.52 (m, CH, allyl); 3.98 (d, 2 Hsyn, J syn ) 6.5 Hz, allyl); 3.35
(NBu 4)[(CtCP h )2P t(µ-η1:η2-CtCP h )2P d (η3-C3H5)] (2a ).
(NBu4)2[Pt(CtCPh)4] (0.2 g, 0.18 mmol) was added to a pale
yellow solution of {[Pd(η3-C3H5)Cl]2} (0.034 g, 0.09 mmol) in
15 mL of acetone. The solution immediately turned deep
yellow and in a few minutes (∼2) a yellow solid began to
precipitate. After 45 min of stirring at room temperature the
yellow solid was separated by filtration and identified as the
neutral trinuclear derivative {Pt(CtCPh)4[Pd(η3-C3H5)2} 3a
(yield 9%). Evaporation of the filtrate to dryness and treat-
ment with cold EtOH (∼4 mL) afforded complex 2a as a yellow
solid (yield 11%). Anal. Calcd for C51H61NPtPd: C, 61.90; H,
6.21; N, 1.42. Found: C, 61.65; H, 6.61; N, 1.34. ΛM: 84 Ω-1
cm2 mol-1. IR (cm-1, in CH2Cl2 solution): ν(CtC) 2098 (vs,
sh); 2026 (s). 1H NMR (CDCl3): at 15 °C 7.43, 7.16 (m, 20 H,
Ph); 5.46 (m, CH, allyl); 3.88 (d, 2 Hsyn, J syn ) 6.04 Hz, allyl);
3.41 (m, 8 H, NCH2-, nBu); 3.28 (d, 2 Hanti, J anti ) 12.1 Hz);
1.54 (m, 8H, -CH2-, nBu); 1.37 (m, 8H, -CH2-, nBu); 0.8 (t, 12H,
-CH3, nBu).
2
(d, 2 Hanti, J anti ) 12.2 Hz, allyl); 3.11 (d, 3H, J P-H ) 13 Hz,
PMePh3+). At -50 °C 7.75 (m), 7.57 (m), 7.13 (d) (25H, Ph);
5.62 (m, CH, allyl); 4.02 (d, 2 Hsyn, J syn ) 6.25 Hz, allyl); 3.36
2
(d, 2 Hanti, J anti ) 12.2 Hz, allyl); 3.09 (d, 3H, J P-H ) 13.12
Hz, PMePh3+). 19F NMR (CDCl3). At 15 °C -116.03 (d, o-F,
3J Pt-o-F ) 399 Hz); -166.44 (m, p-F and m-F). At -50 °C
3
-116.1 (dd, o-F, J Pt-o-F ) 399 Hz); -165.4 (t, p-F); -165.7
(m, m-F). Due to the low solubility and stability of 1a in
solution, its 13C NMR spectrum could not be registered.
(NBu 4)[cis-(C6F 5)2P t(µ-η1:η2-CtCtBu )2P d (η3-C3H5)] (1b).
To a pale yellow solution of {[Pd(η3-C3H5)Cl]2} (0.0233 g, 0.064
mmol) in acetone (10 mL) was added (NBu4)2[cis-Pt(C6F5)2(CtCt-
Bu)2] (0.15 g, 0.128 mmol), and the mixture was stirred for 25
min. The resulting deep yellow solution was evaporated to
dryness, and treatment of the residue with deoxygenated water
afforded 1b as a yellow solid which was repeatedly washed
with deoxygenated water and air-dried (yield 78%). Anal.
Calcd for C43F10H59NPtPd: C, 47.76; H, 5.50; N, 1.30. Found:
C, 47.8; H, 5.40; N, 1.36. ΛM: 93 Ω-1 cm2 mol-1. IR (cm-1):
ν(CtC) 2015 (m); ν(C6F5)x-sensitive 788 (s), 778 (s). 1H NMR
(CDCl3): at 15 °C, 5.3 (m, CH, allyl); 4.43 (d, 2 Hsyn, J syn ) 6.5
Hz, allyl); 3.06 (m, 10 H, overlapping: 2 Hanti, allyl and 8 H,
NCH2-, nBu); 1.54 (m, 8H, -CH2-, nBu); 1.31 (m, 8H, -CH2-, nBu);
1.15 (s, 18H, tBu); 0.89 (t, 12H, -CH3, nBu). The same pattern
(NBu 4)[(CtCtBu )2P t(µ-η1:η2-CtCtBu )2P d (η3-C3H5)] (2b).
{[Pd(η3-C3H5)Cl]2} (0.0352 g, 0.096 mmol) was added to a
colorless solution of (NBu4)2[Pt(CtCtBu)4]‚2H2O (0.2 gr, 0.19
mmol) in acetone (30 mL), and the mixture was stirred for 10
min at room temperature. The resulting deep yellow solution
was concentrated to small volume (∼5 mL) and cooled over-
night to -30 °C, yielding 2b as a yellow solid which was
filtered and washed with cold EtOH (yield 34%). Anal. Calcd
for C43H77NPtPd: C, 56.78; H, 8.53; N, 1.54. Found: C, 56.2;
H, 8.23; N, 1.95. ΛM: 76 Ω-1 cm2 mol-1. IR (cm-1): ν(CtC)
2095 (s); 2020 (s). IR (cm-1, in CH2Cl2 solution): ν(CtC) 2097-
(m); 2009(s). 1H NMR (CDCl3): at 15 °C, 5.23 (m, CH, allyl);
4.37 (d, 2 Hsyn, J syn ) 6.5 Hz, allyl); 3.56 (m, 8 H, NCH2-, nBu);
3.08 (d , 2 Hanti, J anti ) 12.2 Hz); 1.66 (m, 8H, -CH2-, nBu); 1.54
was found at -50 °C: 5.3 (m, CH, allyl); 4.45 (d, 2 Hsyn, J syn
)
4.95 Hz, allyl); 2.98 (br, 10 H, overlapping: 2 Hanti, allyl and
8 H, NCH2-, nBu); 1.47 (br, 8H, -CH2-, nBu); 1.22 (br, 8H, -CH2-,
t
nBu); 1.13 (s, 18H, Bu); 0.85 (br, 12H, -CH3, nBu). 19F NMR
(CDCl3): at 15 °C -115.0 (dm, o-F, 3J Pt-o-F ) 416 Hz); -167.5
(m, m-F); -167.9 (t, p-F). The same pattern was found at -50
°C: -115.1 (d, o-F, 3J Pt-o-F ) 412 Hz); -166.8 (m, m-F); -167.3
(t, p-F). 13C NMR (CDCl3): at -50 °C 149.3 (d), 146.3 (d), 136.8
(m, 8H, -CH2-, nBu); 1.17 (s, 36 H, Bu); 0.99 (t, 12H, -CH3,
t
nBu). At -50 °C: 5.25 (m, CH, allyl); 4.40 (d, 2 Hsyn, J syn
)
n
6.1 Hz, allyl); 3.50 (br, 8 H, NCH2-, Bu); 3.07 (d , 2 Hanti, J anti
t
2
) 12.1 Hz); 1.66 (br, 8H, -CH2-, nBu); 1.52 (m br, 8H, -CH2-,
(m), 133.6 (m) (C6F5); 106.4 (s, Câ, -CRtCâ Bu, J Pt-C ) 281.7
nBu); 1.13 (s, 36 H, Bu); 0.97 (t, 12H, -CH3, nBu). 13C NMR
t
(22) Cross, R. J .; Davidson, M. F. J . Chem. Soc., Dalton Trans. 1986,
1987.
(23) (a) Tatsuno, Y.; Yoshida, T.; Otsuka, S. Inorg. Synth. 1979, 19,
220. (b) Dent, W. T.; Long, R.; Wilkinson, A. J . J . Chem. Soc. 1964,
1585. (c) Harley, F. R.; J ones, S. R J . Organomet. Chem. 1974, 66,
465.
(CDCl3): at -50 °C 110.2 (s), 107.4 (s), 106.1 (s), 90.3 (s), 84.3
t
(s) (2CR, 2Câ, -CRtCâ Bu; CH, allyl); 63.9 (s, -CH2, allyl); 58.2
(s, N-CH2-, NBu4); 32.9 (s, -C(CH3)3); 32.5 (s, -C(CH3)3); 29.7
(s, -CMe3); 29.0 (s, -CMe3); 23.9 (s, -CH2-, NBu4); 19.7 (s, -CH2-,
NBu4); 13.9 (s, -CH3, NBu4).

Reactions of (σ-Alkynyl)platinum Complexes
Organometallics, Vol. 15, No. 21, 1996 4545
The 13C NMR spectrum of the starting complex (NBu 4)2-
[P t(CtCtBu )4]‚2H2O in CDCl3 at room temperature (15 °C)
MgSO4, and, after filtration, the filtrate was evaporated to
dryness. Addition of n-hexane to the residue afforded 3b as a
yellow solid (yield 60%). Anal. Calcd for C30H46PtPd2: C,
44.24; H, 5.69. Found: C, 44.64; H, 6.29. IR (cm-1): ν(CtC)
2016 (vs). 1H NMR (CDCl3): at 15 °C 5.24 (m, 2H, CH, allyl);
4.46 (d, 4Hsyn, J syn ) 6.3 Hz); 2.95 (d, 4Hanti, J anti ) 11.1 Hz),
t
was also registered: 108.4 (s, Câ, -CRtCâ Bu, 2J Pt-C ) 279 Hz);
t
98.9 (s, CR, -CRtCâ Bu, 1J Pt-C ) 975 Hz); 58.6 (s, NCH2-, NBu4);
32.6 (s, -C(CH3)3); 28.9 (s, -CMe3); 24.2 (s, -CH2-, NBu4); 19.5
(s, -CH2-, NBu4); 13.5 (s, -CH3, NBu4).
t
(N B u 4 )[(C tC S iMe 3 )2 P t (µ-η1 :η2 -C tC S iMe 3 )2 P d (η3 -
C3H5)] (2c). To a solution of (NBu4)2[Pt(CtCSiMe3)4]‚2H2O
(0.4 gr, 0.36 mmol) in 25 mL of acetone {[Pd(η3-C3H5)Cl]2}
(0.0662 g, 0.18 mmol) was added, and the mixture was stirred
for 5 min. The resulting dark solution was treated with
charcoal and filtered through kieselguhr. Evaporation of the
resulting yellow filtrate to dryness produced 2c as a yellow
solid which was filtered and washed with deoxygenated H2O
(yield 85%). Anal. Calcd for C39H77Si4NPtPd: C, 48.10; H,
7.97; N, 1.44. Found: C, 47.87; H, 7.94; N, 1.51. ΛM: 82 Ω-1
cm2 mol-1. IR (cm-1): ν(CtC) 2042 (s); 2027 (vs); 1953 (vs);
1938 (s). IR (cm-1, in CH2Cl2 solution): ν(CtC) 2042 (vs); 2027
(vs); 1952 (vs); 1941 (sh). 1H NMR (CDCl3): at 15 °C 5.23 (m,
CH, allyl); 4.41 (d 2 Hsyn, J syn ) 6.4 Hz, allyl); 3.50 (m, 8 H,
NCH2-, nBu); 3.01 (d, 2 Hanti, J anti ) 12.6 Hz, allyl); 1.68 (m,
8H, -CH2-, nBu); 1.51 (s, 8H, -CH2-, nBu); 0.98 (t, 12H, -CH3,
nBu); 0.05 (s, 36 H, SiMe3). At -10 °C: see text. At -50 °C
5.24 (m, CH, allyl); 4.42 (d 2 Hsyn, J syn ) 5.9 Hz, allyl); 3.45
(br, 8 H, NCH2-, nBu); 2.99 (d, 2 Hanti, J anti ) 12.2 Hz, allyl);
1.62 (br, 8H, -CH2-, nBu); 1.45 (s, 8H, -CH2-, nBu); 0.95 (t br,
1.16 (s, Bu). The same spectra pattern was observed at -50
°C 5.27 (m, 2H, CH, allyl); 4.47 (d, 4Hsyn, J syn ) 5.7 Hz); 2.93
t
(d, 4Hanti, J anti ) 12 Hz), 1.11 (s, Bu). 13C NMR (CDCl3): at
t
2
-50 °C 107.6 (s, CH, allyl); 107.4 (s, Câ, -CRtCâ Bu, J Pt-C
)
t
1
297.3 Hz); 73.4 (s, CR, -CRtCâ Bu, J Pt-C ) 906.5 Hz); 65.2 (s,
-CH2, allyl); 32.7 (s, -C(CH3)3); 29.97 (s, -CMe3).
{[P t(µ-CtCSiMe3)4][P d (η3-C3H5)]2} (3c). The synthesis
was performed as described for 3b starting from (NBu4)2[Pt-
(CtCSiMe3)4]‚2H2O (0.2 g, 0.18 mmol) and {[Pd(η3-C3H5)Cl]2}
(0.066 gr, 0.18 mmol) (yield 40%). Anal. Calcd for C26H46
-
Si4PtPd2: C, 35.53; H, 5.28. Found: C, 35.6; H, 5.4. IR (cm-1):
ν(CtC) 1954 (vs); 1919 (sh). 1H NMR (CDCl3): at 50 °C 5.34
(m, 2 H, CH, allyl); 4.54 (d , 4 Hsyn, J syn ) 6.7 Hz); 3.09 (d, 4
H
anti, J anti ) 12.3 Hz); 0.14 (s, 36 H, SiMe3). At 15 °C 5.32 (m,
2 H, CH, allyl); 4.53 (d br, 4 Hsyn, J syn ) 4.2 Hz); 3.12 (d, J anti
) 12.6 Hz), 3.06 (d, J anti ) 12.5 Hz) (4 Hanti); 0.13 (s, 36 H,
SiMe3). At -50 °C 5.32 (m, 2 H, CH, allyl); 4.52 (t br, 4 Hsyn);
3.11 (d), 3.04 (d) (4 Hanti, ca. 1:1.4 ratio, J anti ) 12.3 Hz); 0.10
(s), 0.09 (s) (36 H, SiMe3). 13C NMR (CDCl3): at -50 °C 112.6
1
(s, CR, -CRtCâSiMe3, J Pt-C ) 876.7 Hz); 110.0 (s, CR, -CRtCâ-
n
1
12H, -CH3, Bu); 0.03 (s, 18 H, SiMe3), 0.002 (s, 18 H, SiMe3).
SiMe3, J Pt-C ) 875.8 Hz); 109.5 (s, CH, allyl); 109.1 (s, CH,
13C NMR (CDCl3): at -50 °C 130.5 (s, CRterm., -CRtCâSiMe3,
allyl); 96.6 (s, Câ, -CRtCâSiMe3, J Pt-C ) 267.5 Hz); 96.3 (s,
2
1
2
1J Pt-C ) 990.3 Hz); 119.2 (s, CRbridg., -CRtCâSiMe3, J Pt-C
)
Câ, -CRtCâSiMe3, J Pt-C ) 267 Hz); 66.8 (s, -CH2, allyl); 66.7
724.2 Hz); 108.2 (s, CH, allyl); 106.2 (s, Câterm., -CRtCâSiMe3,
(s, -CH2, allyl); 1.37 (s, SiMe3); 1.26 (s, SiMe3).
2J Pt-C ) 267 Hz); 93.9 (s, Câbridg., -CRtCâSiMe3, J Pt-C ) 244.8
2
[cis-(P P h 3)2P t(µ,η1:η2-CtCR)2P d (η3-C3H5)](ClO4) (R )
t
Hz); 66.0 (s, -CH2, allyl); 58.2 (s, N-CH2-, NBu4); 23.9 (s, -CH2-,
NBu4); 19.6 (s, -CH2-, NBu4); 14.0 (s, -CH3, NBu4); 1.42 (s,
SiMe3); 1.37 (s, SiMe3).
The 13C NMR spectrum of the starting complex (NBu 4)2-
P h (4a ), Bu (4b)). A typical preparation (complex 4a ) was
as follows: To a solution of {[Pd(η3-C3H5)Cl]2} (0.04 g, 0.11
mmol) in acetone (15 mL) was added [cis-Pt(CtCPh)2(PPh3)2]
(0.2 g, 0.22 mmol). After 5 min of stirring, the reaction mixture
was treated with an excess of NaClO4 and stirred for 20 min.
The resulting dark mixture was evaporated to dryness and
the product extracted with CH2Cl2 (15 mL). The dichloro-
methane solution was treated with charcoal and filtered
through kieselguhr. Evaporation of the filtrate to dryness and
addition of EtOH yielded 4a as a white solid (yield 75%).
Complex 4b was prepared as a pale yellow solid in a similar
way to 4a using [cis-Pt(CtCtBu)2(PPh3)2] as the starting
material (yield 60%).
[P t(CtCSiMe3)4]‚2H2O in CDCl3 at room temperature (15
1
°C) was also registered: 140.4 (s, CR, -CRtCâSiMe3, J Pt-C
)
2
924 Hz); 104.4 (s, Câ, -CRtCâSiMe3; J Pt-C ) 250.4 Hz); 58.7
(s, N-CH2-, NBu4); 24.3 (s, -CH2-, NBu4); 19.5 (s, -CH2-, NBu4);
13.7 (s, -CH3, NBu4); 1.3 (s, SiMe3).
{[P t(µ-CtCP h )4][P d (η3-C3H5)]2} (3a ). A solution of (N-
Bu4)2[Pt(CtCPh)4] (0.25 g, 0.23 mmol) in 10 mL of acetone
was treated with 0.084 g (0.23 mmol) of {[Pd(η3-C3H5)Cl]2}
immediately producing a yellow precipitate (3a ) which was
filtered off and washed with acetone (yield 78%). Anal. Calcd
for C38H30PtPd2: C, 51.02; H, 3.38. Found: C, 50.9; H, 3.46.
IR (cm-1): ν(CtC) 2023 (vs). 1H NMR (CDCl3): at 40 °C 7.55,
Data for 4a : Anal. Calcd for C55H45P2ClO4PtPd: C, 56.52;
H, 3.88. Found: C, 56.28; H, 3.85. ΛM: 128 Ω-1 cm2 mol-1
.
IR (cm-1): ν(CtC) not observed. 1H NMR (CDCl3): at 15 °C
7.39 (m, 36 H, overlap Ph (PPh3) with p-H and m-H (CtCPh)];
6.7 (d, 4H, o-H (CtCPh), J H-H ) 7.31 Hz); 5.63 (m, CH, allyl);
3.82 (m overlapping of doublets, 2 Hanti, 2 Hsyn, allyl). A similar
pattern was observed at -50 °C 7.34 [m, 36 H, overlap Ph
(PPh3) with p-H and m-H (CtCPh)]; 6.62 (d, 4H, o-H (CtCPh),
J H-H ) 7.2 Hz); 5.65 (m, CH, allyl); 3.86 (d, 2 Hanti, J anti ) 12.2
Hz, allyl); 3.78 (d 2 Hsyn, J syn ) 6.14 Hz, allyl). 31P NMR
7.32 (m, 20 H, Ph); 5.50 (m, 2 H, CH, allyl); 3.93 (d, 4 Hsyn
,
J syn ) 6.5 Hz, allyl); 3.39 (d, 4 Hanti, J anti ) 12.1 Hz). At 30 °C
the allyl resonances show a similar sharp pattern. At 15 °C
7.55, 7.31 (m, 20 H, Ph); 5.51 (br hump, 2 H, CH, allyl); 3.93
(br, 4 Hsyn, allyl); 3.41 (d br, 4 Hanti, J anti ) 11.1 Hz, allyl). At
10 °C the CH and the syn and anti protons resonances remain
broad but at 0 °C the central proton appears again as a
multiplet and the syn and anti protons split in different signals
(ca. 1:1.4 ratio). At -30 °C 7.52, 7.33 (m, 20 H, Ph); 5.45 (m,
2 H, CH, allyl); 3.99 (d, J syn ) 6.4 Hz), 3.90 (d, J syn ) 6.5 Hz)
1
(CDCl3): at 15 °C 12.7, J Pt-P ) 2652 Hz. At -50 °C 12.7,
1J Pt-P ) 2647 Hz. 13C NMR (CDCl3): at -50 °C 134.0 (m, Ph,
1
PPh3, o-C); 131.8 (s, Ph), 131.1 (s, Ph); 129.2 (AXX′, J C-P
+
[4 Hsyn, 1:1.16 ratio]; 3.43 (d, J anti ) 12.3 Hz), 3.41 (d, J anti
)
3J C-P′ ) 59.7 Hz, Ph, PPh3, ipso-C); 128.8 (s, Ph); 128.5 (t, J P-C
12.2 Hz) (4 Hanti). At -50 °C 7.52, 7.25 (m, 20 H, Ph); 5.62
(overlapping of two multiplets, 2 H, CH, allyl); 4.02 (d), 3.92
(d) [4 Hsyn, 1.16:1 ratio, J syn ) 6.3 Hz]; 3.43 (overlapping of
two doublets, 4 Hanti, J anti ) 12.2 Hz, allyl). The 13C NMR
spectrum could not be obtained due to the low solubility of
the complex.
) 5.3 Hz, Ph, PPh3, m-C); 128.0 (s, Ph), 123.9 (s, Ph, ipso-C);
3
113.1 (s, CH, allyl); 102.8 (AXX′, Câ, -CRtCâPh, J Ptrans-C
+
3J Pcis-C ) 30.6 Hz); 84.7 (dd, CR, -CRtCâPh, J Ptrans-C ) 134.6
2
2
Hz, J Pcis-C ) 18.8 Hz); 76.5 (s, CH2, allyl).
Data for 4b: Anal. Calcd for C51H53P2ClO4PtPd: C, 54.26;
H, 4.73. Found: C, 53.97; H, 4.72. ΛM: 126 Ω-1 cm2 mol-1
.
{[P t(µ-CtCtBu )4][P d (η3-C3H5)]2} (3b). To a stirred sus-
pension of (NBu4)2[Pt(CtCtBu)4]‚2H2O (0.3 g, 0.29 mmol) in
acetone (10 mL) {[Pd(η3-C3H5)Cl]2} (0.105 g, 0.29 mmol) was
added immediately giving a deep yellow solution. After 10 min
of stirring the solution was evaporated to dryness and the
resulting residue was treated with deoxygenated water, giving
a yellow solid which was filtered and washed with water. The
yellow product was dissolved in CH2Cl2 (20 mL), dried with
IR (cm-1): ν(CtC) 2040 (w), 2020 (sh). 1H NMR (CDCl3): at
15 °C 7.30, 7.23 (m, 30 H, Ph); 5.5 (m, CH, allyl); 4.64 (d 2
H
syn, J syn ) 6.2 Hz, allyl); 3.34 (d 2 Hanti, J anti ) 12.3 Hz, allyl);
0.80 (s, 18 H, Bu). 31P NMR (CDCl3): at 15 °C 12.62, J Pt-P
) 2671 Hz. The same spectra patterns were observed at -50
°C. 1H NMR (CDCl3): 7.30 (m, 30 H, Ph); 5.46 (m, CH, allyl);
4.63 (d 2 Hsyn, J syn ) 6 Hz, allyl); 3.35 (d 2 Hanti, J anti ) 12.2
t
1
Hz, allyl); 0.77 (s, 18 H, Bu). 31P NMR (CDCl3) 12.68, J Pt-P
t
1

4546 Organometallics, Vol. 15, No. 21, 1996
Berenguer et al.
) 2659 Hz. 13C NMR (CDCl3): at -50 °C 134.0 (t, J P-C ) 5.4,
used. A total of 8175 reflections were collected in the range
of 4° < 2θ < 48° (h,k,l: 0 to 24, 0 to 18, -33 to 33) using ω-θ
scans. Absorption correction was based on ψ-scan solutions
(maximum and minimum transmission factors: 0.4840 and
0.3574, respectively). The structure was solved by the Patter-
son method and refined with all atoms (except for disordered
ClO4- anion) with anisotropic displacement parameters. Hy-
drogen atoms were not included in the structural model. The
highest peak on the final difference Fourier map corresponds
to 0.93 e Å-3 (largest hole -1.27 e Å-3).
1
Ph, o-C); 130.8 (s, Ph, p-C), 129.6 (AXX′, J C-P+3J C-P′ ) 59
Hz, Ph, ipso-C); 128.3 (t, J P-C ) 5.1 Hz, Ph, m-C); 112.5 (AXX′,
t
3
3
Câ, -CRtCâ Bu, J Ptrans-C + J Pcis-C ) 29.4 Hz); 111.0 (s, CH,
t
2
2
allyl); 75.6 (dd, CR, -CRtCâ Bu, J Ptrans-C ) 135.1 Hz, J Pcis-C
) 19.2 Hz); 31.5 (s, -C(CH3)3); 29.9 (s, -CMe3).
[cis-P t(CtCP h )2(P P h 3)2]. 13C NMR (CDCl3): at -50 °C
134.4 (t, o-C, J P-C ) 5.6, Ph, PPh3); 131.3 (s, Ph), 131.4 (AXX′,
1
3
ipso-C, J C-P + J C-P′ ) 55.3 Hz); 129.7 (s, Ph), 127.5 (t, J P-C
) 5.2 Hz, Ph, m-C); 126.7 (s, Ph, -CtCPh); 124.6 (s, ipso-C,-
3
3
Ph, -CtCPh); 109.8 (AXX′, Câ, -CRtCâPh, J Ptrans-C + J Pcis-C
2
) 34 Hz); 102.6 (dd, CR, -CRtCâPh, J Ptrans-C ) 149.9 Hz,
Ack n ow led gm en t. We would like to thank the
Comisio´n Interministerial de Ciencia y Tecnolog´ıa
(Spain, Project PB 92-0364) for its financial support and
for a grant (to J .R.B.). E. Lalinde also thanks the
University of La Rioja for its financial support.
2J Pcis-C ) 21 Hz).
[cis-P t(CtCtBu )2(P P h 3)2]. 13C NMR (CDCl3): at -50 °C
1
134.5 (t, o-C, J P-C ) 5.6, Ph); 132.2 (AXX′, J C-P
+ )
3J C-P′
53.6 Hz, Ph, ipso-C); 129.3 (s, Ph, p-C), 127.2 (t, J P-C ) 5.3
t
3
Hz, Ph, m-C); 117.1 (AXX′, Câ, -CRtCâ Bu, J Ptrans-C + 3J Pcis-C
t
) 33.9 Hz, 2J Pt-C ) 305 Hz); 85.8 (dd, CR, -CRtCâ Bu, 2J Ptrans-C
2
1
Su p p or tin g In for m a tion Ava ila ble: Tables of refined
cell constants with the most relevant data, anisotropic thermal
parameters, atom positional parameters, and complete list of
bond lengths and angles for 4b (8 pages). Ordering informa-
tion is given on any current masthead page.
) 152 Hz, J Pcis-C ) 21 Hz, J Pt-C ) 1132.5 Hz); 31.2 (s,
4
3
-C(CH3)3, J Pt-C ) 7.7 Hz); 29.87 (s, -CMe3, J Pt-C ) 21.2 Hz).
X-r a y Cr ysta l Str u ctu r e Deter m in a tion of [cis-(P P h 3)2-
P t(µ,η1:η2-CtCtBu )2P d (η3-C3H5)](ClO4) (4b). Suitable crys-
tals of complex 4b were obtained by slow diffusion of n-hexane
over a concentrated solution of the complex in CH2Cl2. Dif-
fraction data were collected on a Siemens/STOE-AED2 dif-
fractometer with graphite-monochromated Mo KR radiation
and were corrected for Lorentz and polarization effects.
SHELXTL-PLUS24 crystallographic software package was
OM9603326
(24) SHELXTL-PLUS, Software Package for the Determination
Crystal Structure, Release 4.0, Siemens Analytical X-Ray Instrument,
Inc., Madison, WI, 1990.