Synthesis of Bis(η2-alkyne) trinuclear zwitterionic platinum hydride complexes by reaction of [trans-Pt(C6F5)2(C≡CR)2] 2- with the solvento species [trans-PtHL2(acetone)]

Article abstract of DOI:10.1021/om950827f

The alkynylation of trans-[Pt(C₆F₅)₂(tht)₂] (tht = tetrahydrothiophene) with LiC≡CR in diethyl ether (R = Ph, SiMe₃) or THF (R = ^tBu) leads to novel dianionic species [trans-Pt-(C₆F₅)₂(C≡CR)₂] ^2- (R = Ph (1), SiMe₃ (2), ^tBu (3)) which have been isolated as tetrabutylammonium salts. Treatment of (NBu₄)₂[trans-Pt(C₆F₅) ₂(C≡CR)₂] (R = Ph, SiMe₃, ^tBu) with 2 equiv of cationic hydride reagents of the type [trans-PtHL₂(acetone)]⁺ (L = PPh₃, PEt₃) in acetone form, via a ligand replacement, simple bis(η²-alkyne) trinuclear zwitterionic complexes trans,trans,trans-{[Pt(C₆F₅)₂(μ-η ¹:η²-C≡CR)₂](PtHL₂) ₂} (R = Ph, L = PPh₃ (4a), PEt₃ (4b); R = SiMe₃, L = PPh₃ (5a), PEt₃ (5b); R = ^tBu, L = PEt₃ (6b)). The structure of complex 4b has been determined by X-ray diffraction methods.

Full text of DOI:10.1021/om950827f

1820
Organometallics 1996, 15, 1820-1825
Syn th esis of Bis(η2-a lk yn e) Tr in u clea r Zw itter ion ic
P la tin u m Hyd r id e Com p lexes by Rea ction of
[tr a n s-P t(C6F 5)2(CtCR)2]2- w ith th e Solven to Sp ecies
[tr a n s-P tHL2(a ceton e)]+
Irene Ara,† J esu´s R. Berenguer,‡ J uan Fornie´s,*,† Elena Lalinde,*,‡ and
M. Teresa Moreno‡
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, and Departamento de Qu´ımica, Universidad de La Rioja,
26001 Logron˜o, Spain
Received October 17, 1995X
The alkynylation of trans-[Pt(C6F5)2(tht)2] (tht ) tetrahydrothiophene) with LiCtCR in
t
diethyl ether (R ) Ph, SiMe3) or THF (R ) Bu) leads to novel dianionic species [trans-Pt-
t
(C6F5)2(CtCR)2]2- (R ) Ph (1), SiMe3 (2), Bu (3)) which have been isolated as tetrabutyl-
ammonium salts. Treatment of (NBu4)2[trans-Pt(C6F5)2(CtCR)2] (R ) Ph, SiMe3, tBu) with
2 equiv of cationic hydride reagents of the type [trans-PtHL2(acetone)]+ (L ) PPh3, PEt3) in
acetone form, via a ligand replacement, simple bis(η2-alkyne) trinuclear zwitterionic
complexes trans,trans,trans-{[Pt(C6F5)2(µ-η1:η2-CtCR)2](PtHL2)2} (R ) Ph, L ) PPh3 (4a ),
t
PEt3 (4b); R ) SiMe3, L ) PPh3 (5a ), PEt3 (5b); R ) Bu, L ) PEt3 (6b)). The structure of
complex 4b has been determined by X-ray diffraction methods.
Ch a r t 1
In tr od u ction
A large number of transition σ-alkynyl complexes
have been described, and it is well-known that the
reactivity of the alkynyl ligand is a sensitive function
of the nature of the alkynyl substituent, the attached
metal and its ligands, and the overall charge of the
complex.1 It is well documented that alkynyl complexes
containing electron-donating transition metal fragments
generally undergo R-attack by nucleophiles and â-attack
by electrophiles.1bd,2 This reactivity has been rational-
ized on the basis of resonance forms A and B (Chart 1),
with form B becoming more important as the electron
density on the complex increases and as the ligands and
the alkynyl substituents become more electron releas-
ing.
compounds have been scarcely explored. The few cases
that have been published show quite a normal behavior
on the basis of the established trends in reactivity of
metal-alkynyl complexes and metal hydrides (Scheme
1). For example, Bullock et al. have shown that
relatively acidic transition-metal hydrides, such as Cp-
(CO)3MH (M ) Cr, Mo, W), protonate the â-carbon of
metal-alkynyl complex [Cp(PMe3)2RuCtCMe] render-
ing the cationic ruthenium vinylidene with a metal
anion as counterion (Scheme 1a).4 Opposite regiochem-
istry has been observed in the reaction of the same
alkynyl complex with the hydridic metal hydride [Cp2-
ZrHCl]n which provides the corresponding 1,2-dimetal-
loalkene (Scheme 1b).5 Lukehart and co-workers have
also nicely demonstrated that the Pt-H bond of [trans-
PtH(PEt3)2(acetone)]+ adds regioselectively across the
CtC triple bond of terminal alkynyl ligands to give
homo- or heterodinuclear complexes containing bridging
alkenylidene ligands (Scheme 1c).6 The mechanism for
these Pt-H addition reactions has not been fully proved,
although it has been pointed out that the regiochemistry
observed is that expected for having initial coordination
of the CtC multiple bond to the coordinatively unsatur-
ated complex [HPt(PEt3)2]+, followed by 1,2-addition of
the polarized bond Ptδ--Hδ+ across the unsaturated
The insertion of acetylenes into a M-H bond, which
is a fundamental step of many catalytic cycles, is a well-
known process;3 however, in spite of the similarity
between σ-alkynyl complexes and acetylenes, the reac-
tions of transition-metal hydrides with metal-alkynyl
† Universidad de Zaragoza.
‡ Universidad de La Rioja.
X Abstract published in Advance ACS Abstracts, March 1, 1996.
(1) (a) Nast, R. Coord. Chem. Rev. 1982, 47, 89. (b) Bruce, M. I.;
Swincer, A. G. Adv. Organomet. Chem. 1983, 22, 59. (c) Bruce, M. I.
Pure Appl. Chem. 1990, 62, 1021. (d) Bruce, M. I. Chem. Rev. 1991,
91, 197.
(2) (a) Davison, A.; Selegue, J . P. J . Am. Chem. Soc. 1980, 102, 2455.
(b) Davison, A.; Selegue, J . P. J . Am. Chem. Soc. 1978, 10, 7763. (c)
Wong, A.; Pawlick, R. V.; Thomas, Ch. G.; Leon, D. R.; Liu, L.-K.
Organometallics 1991, 10, 530. (d) Akita, M.; Terada, M.; Oyama, S.;
Moro-Oka, Y. Organometallics 1990, 9, 816 and references therein.
(e) Kelley, C.; Lugan, N.; Terry, M. R.; Geoffroy, G. L.; Haggerty, B.
S.; Rheingold, A. L. J . Am. Chem. Soc. 1992, 114, 6735 and references
therein. (f) For a theoretical treatment see: Kostic, N. M.; Fenske, R.
F. Organometallics 1982, 1, 974.
(3) (a) Crabtree, R. H. The Organometallic Chemistry of the Transi-
tion Metals; Wiley: New York, 1988; pp 142-162. (b) Masters, C.
Homogeneous Transition-Metal Catalysis. A Gentle Art; Chapman and
Hall: New York, 1981.
(4) Bullock, R. M. J . Am. Chem. Soc. 1987, 109, 8087.
(5) (a) Bullock, R. M.; Lemke, F. R.; Szalda, D. J . J . Am. Chem. Soc.
1990, 112, 3244. (b) Lemke, F. R.; Szalda, D. J .; Bullock, R. M. J . Am.
Chem. Soc. 1991, 113, 8466. (c) A similar Zr/Zr dimetalloalkene has
been obtained from [Cp′2Zr(CtCMe)Cl]: Erker, G.; Fro¨mberg, W.;
Angermund, K.; Schlund, R.; Kru¨ger, C. J . Chem. Soc., Chem. Com-
mun. 1986, 372.
(6) (a) Afzal, D.; Lukehart, C. M. Organometallics 1987, 6, 546. (b)
Afzal, D.; Lenhert, P. G.; Lukehart, C. M. J . Am. Chem. Soc. 1984,
106, 3050.
0276-7333/96/2315-1820$12.00/0 © 1996 American Chemical Society

Trinuclear Platinum Hydride Complexes
Organometallics, Vol. 15, No. 7, 1996 1821
Sch em e 1
[trans-Pt(C6F5)2(tht)2] +
LiCtCR + NBu4Br (excess) f
(NBu ) [trans-Pt(C F ) (CtR) ]
bond, with the H ligand adding to the â-carbon atom.
In the course of the last few years we have been
investigating the ability of the very reactive anionic
alkynyl substrates [Pt(CtCR)4]2- and [cis-Pt(C6F5)2-
(CtCR)2]2- to stabilize polynuclear platinum complexes
bearing alkynyl groups as unique bridging ligands.7
Continuing our work in this field, here we describe the
syntheses and characterization of the corresponding
dianionic [trans-Pt(C6F5)2(CtCR)2]2- species stabilized
with NBu4+ cations as counterions and also report their
reactions with [trans-PtHL2(acetone)]+ (L ) PPh3, PEt3)
in a 1:2 molar ratio. Surprisingly and in contrast with
Lukehart’s results, these reactions afford simple tri-
nuclear zwitterionic complexes trans,trans,trans-{[Pt-
(C6F5)2(µ-η1:η2-CtCR)2](PtHL2)2}, in which the starting
precursor [RCtCPtL2CtCR]2- (L ) C6F5) is only acting
as a bridging diyne ligand between two different cationic
[trans-PtHL2]+ fragments. The crystal structure of
tra ns,tra ns,tra ns-{[Pt(C6F5)2(µ-η1:η2-CtCPh)2][PtH-
(PEt3)2]2} (4b) is reported.
+ 2LiBr + 2tht (1)
2
4 2
6
5 2
t
R ) Ph (1), SiMe3 (2), Bu (3)
displacement of both tht ligands and leads to the
formation of the anionic species [trans-Pt(C6F5)2-
(CtR)2]2-, which, by addition of NBu4Br, can be crystal-
+
lized as NBu4 salts in excellent yields (eq 1; see
Experimental Section).
Their analytical and spectroscopic data are given in
the Experimental Section. In agreement with the trans
geometry (D2h) assigned to complexes 1-3, their IR
spectra show a single band (2077 cm-1 (1), 2014 cm-1
(2), 2091 cm-1 (3)) due to ν(CtC) (B2u) along with one
band due to the X-sensitive mode of the C6F5 group.10
As expected, the 19F NMR spectra exhibit signals due
to only one type of C6F5 ligand and the 1H NMR spectra
of 2 and 3 show only singlet resonances for the methyl
groups of the trimethylsilyl or tert-butylalkynyl ligands,
respectively. The 13C NMR spectra of 1 show, in
addition to the expected resonances due to phenyl and
NBu4 groups, two singlet signals at 103.9 and 121.5
ppm, which can be tentatively assigned to the acetylenic
carbon resonances CR and Câ, respectively. However,
Resu lts a n d Discu ssion
While heteroleptic neutral alkynyl mononuclear com-
plexes of platinum are relatively common,1a,8 similar
mixed organo-alkynyl anionic compounds are quite
rare.9 Recently, we have described the synthesis of
t
complexes 2 (R ) SiMe3) and 3 (R ) Bu) show only a
t
anionic (NBu4)2[cis-Pt(C6F5)2(CtCR)2] (R ) Ph, Bu,7b
singlet signal in the acetylenic region due to CR or Câ
atoms (δ 102.1, 2; δ 107.5, 3).
SiMe37e) and have shown that they are suitable precur-
sors for the synthesis of homo- and heterobinuclear
complexes stabilized through a doubly alkynyl bridging
system.7c,e,f In view of these results, we considered the
preparation of the isomeric trans anionic species [trans-
Pt(C6F5)2(CtCR)2]2- of interest since the presence of π
donor ligands in trans positions make them suitable
precursors to di- or trinuclear mono µ-CtCR complexes.
So, complexes (NBu4)2[trans-Pt(C6F5)2(CtCR)2] can
be synthesized by prolongated treatment (24 h) of trans-
[Pt(C6F5)2(tht)2] (tht )tetrahydrothiophene) with an
excess of LiCtCR in diethyl ether (R ) Ph, SiMe3) or
The trans-bis(alkynyl)bis(pentafluorophenyl)platinate-
(II) derivatives 1-3 can be regarded as simple metallo-
1,4-diynes and should be expected to be highly nucleo-
philic and reactive due to the negative charges on the
complexes. Since the Pt-H bond of the cationic hydride
reagents [trans-PtH(PEt3)2]+ is known to add, without
exception, across the alkynyl CtC triple bonds of
metallo6 or elementa (main group) substituted alkynyl
compounds,11 we decided initially to explore their
reactivity toward these anionic substrata (1-3) in order
to ascertain the nature of the resulting products, as well
as the mechanism involved in this type of process.
Treatment of the in situ generated cationic hydride
reagents [trans-PtHL2(acetone)](ClO4) (L ) PPh3, PEt3)
(see Experimental Section) with (NBu4)2[trans-Pt-
(C6F5)2(CtCR)2] (R ) Ph, SiMe3, tBu) in acetone solution
at room temperature for R ) Ph, or at low temperature
t
tetrahydrofuran (R ) Bu) (eq 1). This causes the
(7) (a) 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. (b) Espinet, P.; Fornie´s, J .; Mart´ınez, F.; Lalinde, E.;
Moreno, M. T.; Ruiz, A.; Welch, A. J . J . Organomet. Chem. 1991, 403,
253. (c) Fornie´s, J .; Go´mez-Saso, M. A.; Lalinde, E.; Mart´ınez, F.;
Moreno, M. T. Organometallics 1992, 11, 2873. (d) Fornie´s, J .; Lalinde,
E.; Mart´ın, A.; Moreno, M. T. J . Chem. Soc., Dalton Trans. 1994, 135.
(e) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.; Mart´ınez, F. J . Organomet.
Chem. 1994, 470, C15. (f) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.;
Mart´ın, A.; Moreno, M. T. J . Chem. Soc., Dalton Trans. 1994, 3343.
(g) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.; Mart´ınez, F. J . Chem.
Soc., Chem. Commun. 1995, 1227.
(10) Maslowsky, E., J r. Vibrational Spectra of Organometallic
Compounds; Wiley: New York, 1977; p 437 and references therein.
(11) (a) Lukehart, C. M.; McPhail, A. T.; McPhail, D. R.; Myers, J .
B., J r.; Soni, H. K. Organometallics 1989, 8, 1007. (b) Dema, A. C.; Li,
X.; Lukehart, C. M.; Owen, M. D. Organometallics 1991, 10, 1197 and
references therein. (c) Lukehart, C. M.; McPhail, A. T.; McPhail, D. R.
Organometallics 1991, 10, 372 and references therein. (d) Dema, A.
C.; Lukehart, C. M.; McPhail, A. T.; McPhail, D. R. J . Am Chem. Soc.
1989, 111, 7615. (e) Ibid. 1989, 112, 7229.
(8) Cross, R. J .; Davidson, M. F. J . Chem. Soc., Dalton Trans. 1986,
1987 and references therein.
(9) Sebald, A.; Wrackmeyer, B.; Theocharis, Ch. R.; J ones, W. J .
Chem. Soc., Dalton. Trans. 1984, 741.

1822 Organometallics, Vol. 15, No. 7, 1996
Ara et al.
t
(-10 °C) for R ) SiMe3 or Bu, in a 2:1 molar ratio,
afforded, unexpectedly, the simple bis(µ-alkyne) tri-
nuclear zwitterionic neutral complexes trans,trans,-
trans-{[Pt(C6F5)2(µ-η1:η2-CtCR)2](PtHL2)2} in moderate
(R ) Ph, L ) PPh3 (4a ), PEt3 (4b)) or low yield (R )
t
SiMe3, L ) PPh3 (5a ), PEt3 (5b); R ) Bu, L ) PEt3
(6b)), according to eq 2. However, all attempts to syn-
F igu r e 1. Molecular structure of complex 4b, showing the
atom-numbering scheme.
(2)
the typical pattern of three signals in a 2:1:2 ratio (2
Fo:Fp:2 Fm; 4b, 5b, and 6b) or two signals in a 2:3 ratio
(2 Fo:Fp and 2 Fm; 4a and 5a ) due to two equivalent C6F5
groups, for which the plane of coordination is a mirror
plane. Moreover, the 31P NMR spectra exhibit a singlet
with platinum satellites, consistent with the trans
arrangement of the phosphine ligands in the [PtHL2]
moieties. Finally, the presence of the hydride ligand is
evidenced by a triplet (-9.08 to -11.39 ppm) due to
thesize the analogue derivative 6a by treating
(NBu4)2[trans-Pt(C6F5)2(CtCtBu)2] with 2 equiv of [trans-
PtH(PPh3)2(acetone)]+ were unsuccessful, since the
reactions gave mixtures of products which have not been
further investigated.
Compounds 4a ,b,5a ,b, and 6b were characterized by
elemental analyses and spectroscopic methods (see
Experimental Section). The IR spectra showed a similar
pattern in the ν(Pt-H) and ν(CtC) regions for all
compounds. They exhibit one strong absorption in the
2145-2160 cm-1 range, which can be assigned to the
ν(Pt-H) vibrations and which is typical for terminal
hydride ligands.12 The values observed in our com-
plexes are lower than those reported for the chloride
coupling to two equivalent phosphine ligands (2J H-P
cis
= 13.5 Hz), accompanied by the expected platinum
1
satellites. The relatively high values of J Pt-H (1080-
1255 Hz) is indicative of the terminal nature of the
hydride ligand12 and the relatively low trans influence
of the π-bonded alkynyl ligands. The low stability in
solution of 4b, 5, and 6b and low solubility of 4a
prevented their characterization by 13C NMR spectros-
copy.
13
precursor trans-[PtHClL2] (2220 cm-1 for L ) PPh3
14
and 2210 cm-1 for L ) PEt3 ) but higher than those
reported for complexes of the type trans-[PtH(CtCR)-
L2]15 (2015-2050 cm-1), suggesting that the alkynyl
ligands bound in a π fashion exert a lower trans
influence than when they are σ-bonded but higher than
the Cl atom.
On the other hand, there is a very strong ν(CtC)
absorption (two for 4b and 5a ) in the expected region
(1836-1963 cm-1) for side-on µ-η1:η2-CtCR groups.7
The 19F and 31P NMR spectra give evidence of highly
symmetric systems. Thus, the 19F NMR spectra exhibit
The definitive characterization of 4-6 as bis(η2-
alkyne) trinuclear complexes came from a single-crystal
X-ray diffraction study on complex 4b. A view of the
molecular geometry of this complex is shown in Figure
1. A summary of the fundamental crystallographic data
and stuctural parameters is given in Table 1. Final
positional parameters appear in Table 2, and selected
interatomic distances and angles are listed in Table 3.
This study supports the spectroscopic data and confirms
that the starting dianionic fragment [trans-Pt(C6F5)2-
(CtCPh)2]2- is acting only as a bridging diyne ligand
between two identical cationic [trans-PtH(PEt3)2]+ units
[related by an inversion center located on Pt(1)], which
indicates that the trans geometries around the platinum
centers have been preserved throughout the reaction.
The central Pt(1) atom is located in an approximately
square-planar environment formed by the two Cipso
atoms of C6F5 groups (mutually trans) and one CR
carbon atom of each CtCPh ligand, the Pt(1)-C dis-
tances being similar to those found in the anions {cis-
[Pt(C6F5)2(µ-η1:µ2-CtCPh)2]Ag(PPh3)}- 16 or [cis-Pt-
(C6F5)2(µ-η1:η2-CtCSiMe3)2MLn]- [MLn ) Pd(η3-C3H5),7e
HgBr27f]. The coordination of the terminal platinum
atoms Pt(2) and Pt(2a) can be described as distorted
(12) (a) Michelin, R. A.; Ros, R. J . Chem. Soc., Dalton Trans. 1989,
1149 and references therein. (b) Packett, D. L.; Syed, A.; Trogler, W.
C. Organometallics 1988, 7, 159. (c) Clark, H. C.; Ferguson, G.;
Hampden-Smith, M. J .; Ruegger, H.; Ruhl, B. L. Can. J . Chem. 1988,
66, 310. (d) Michelin, R. A.; Bertani, R.; Mozzon, M.; Zanotto, L;
Benetollo, F.; Bombieri, G. Organometallics 1990, 9, 1449. (e) Cowan,
R. L.; Trogler, W. C. J . Am. Chem. Soc. 1989, 111, 4750. (f) Michelin,
R. A.; Ros, R.; Guadalupi, G.; Bombieri, G.; Benetollo, F.; Chapuis, G.
Inorg. Chem. 1989, 28, 840. (g) Minghetti, G.; Cinellu, M. A.; Stoccoro,
S.; Chelucci, G.; Zucca, A. Inorg. Chem. 1990, 29, 5138. (h) Mullica, D.
F.; Sappenfield, E. L.; Hampden-Smith, M. J . Polyhedron 1991, 10,
867. (i) Lalif, L. A.; Eaborn, C.; Pidcock, A. D.; Weng, Ng. S. J .
Organomet. Chem. 1994, 474, 217. (j) Leoni, P.; Manetti, S.; Pasquali,
M. Inorg. Chem. 1995, 34, 749.
(13) (a) Chatt, J .; Shaw, B. L. J . Chem. Soc. A 1962, 5075. (b) Bailar,
J . C.; Itatani, H. Inorg. Chem. 1965, 4, 1618. (c) Parshall, G. W. Inorg.
Synth. 1970, 12, 28.
(14) (a) Bergamini, P.; Sostero, S.; Traverso, O.; Venanzi, L. M.
Inorg. Chem. 1990, 29, 4376. (b) Church, M. J .; Mays, M. J . J . Chem.
Soc. A 1968, 3074.
(15) (a) Furlani, A.; Licoccia, S.; Russo, M. V.; Chiesi Villa, A.;
Guastini, C. J . Chem. Soc., Dalton Trans. 1982, 2449. (b) Glockling,
F.; Hooton, K. A. J . Chem. Soc. A 1967, 1066.
(16) Fornie´s, J .; Lalinde, E.; Mart´ınez, F.; Moreno, M. T.; Welch, A.
J . J . Organomet. Chem. 1993, 455, 271.

Trinuclear Platinum Hydride Complexes
Organometallics, Vol. 15, No. 7, 1996 1823
Ta ble 1. Cr ysta llogr a p h ic Da ta a n d Str u ctu r e
Refin em en t P a r a m eter s for tr a n s,tr a n s,tr a n s-
{[P t(C6F 5)2(µ-η1:η2-CtCP h )2][P tH(P Et3)2]2} (4b)
Ta ble 2. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t Coefficien ts
(Å2 × 103) for tr a n s,tr a n s,tr a n s-
{[P t(C6F 5)2(µ-η1:η2-CtCP h )2][P tH(P Et3)2]2} (4b)
empirical formula
fw
C52H72F10P4Pt3
1596.30
x
y
z
U(eq)a
cryst system
space group
unit cell dimens
triclinic
Ph1
a ) 10.438(3) Å, R ) 89.98(2)°
b ) 11.863(4) Å, â ) 73.88(2)°
c ) 13.071(4) Å, γ ) 69.68(2)°
1449.81 Å3
Pt(1)
Pt(2)
P(1)
P(2)
F(2)
F(3)
F(4)
F(5)
F(6)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
0
5000
5000
32(1)
44(1)
52(1)
56(1)
56(2)
552(1)
-1620(3)
2583(3)
-3038(5)
-3690(7)
-1573(8)
1205(7)
1897(5)
-507(9)
-1927(11)
-2296(11)
-1244(14)
166(11)
3116(1)
3117(2)
2948(3)
4902(5)
3495(7)
1694(8)
1431(7)
2854(5)
3943(7)
4056(9)
3320(11)
2421(11)
2298(9)
3067(8)
3488(7)
2466(8)
1261(9)
1082(11)
15(15)
2360(1)
3344(2)
1022(2)
6458(4)
7914(6)
8452(7)
7537(7)
6081(5)
6191(7)
6691(8)
7436(9)
7722(10)
7263(9)
6517(8)
4013(7)
3551(7)
3359(8)
3787(9)
3605(12)
3033(13)
2604(12)
2756(9)
4467(11)
5015(20)
4453(26)
3950(10)
3080(13)
2559(13)
1912(17)
-20(11)
444(14)
240(12)
-143(14)
1394(9)
458(11)
V
Z
89(4)
2
126(5)
105(4)
61(3)
40(4)
55(5)
64(5)
80(6)
65(5)
47(4)
36(3)
44(4)
60(5)
86(6)
118(8)
116(9)
104(8)
78(6)
D(calc)
abs coeff
F(000)
cryst size
temp
wavelength
2θ range for data collcn
index ranges
1.10 Mg/m3
7.39 mm-1
768.0
0.23 × 0.34 × 0.11 mm
200(1) K
0.710 73 Å
4-47°
-12 e h e 12, -13 e k e 13,
0 e l e 15
484(10)
1069(9)
1797(9)
reflcns collcd
indepdt reflcns
4329
3863 (Rint ) 0.0347)
2999/0/324
1.131
C(9)
2906(11)
4077(13)
5182(16)
5159(19)
4041(18)
2881(14)
-1521(12)
-2935(25)
-804(31)
-2961(10)
-3296(14)
-2508(15)
-1704(24)
2234(15)
1532(18)
3447(16)
2550(18)
4024(11)
5384(14)
data/restraints/params
goodness-of-fit indicatora
R indices [2999 reflcns with
I > 2σ(I)]a
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(16′)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
R ) 0.0325, wR ) 0.0437
-911(14)
-794(12)
319(8)
R indices (all 3863 data)a
mean, max |shift/esd|,
final cycle
R ) 0.0462, wR ) 0.0473
0.000, 0.000
2196(10)
2069(24)
938(27)
4612(9)
5451(11)
2537(14)
1400(16)
3948(17)
5304(14)
1428(14)
941(15)
3132(13)
3052(18)
74(6)
78(12)
105(15)
67(5)
95(7)
98(8)
146(13)
109(10)
105(9)
105(8)
125(10)
77(6)
largest diff peak and hole
1.15 and -0.91 e/Å3
R ) ∑(|Fo| - |Fc|)/∑|Fo|. wR ) [∑w (|Fo| - |Fc|)2/∑w |Fo| ]1/2
.
a
2
Goodness-of-fit ) [∑w (|Fo| - |Fc|)2/(Nobs - Nparam)]1/2
.
w ) 1/σ2
(F) + 0.001051 F2.
square-planar. The Pt(2) atom is linked to two phos-
phine ligands (mutually trans) and π bonded to the
carbon-carbon triple bond of the C(7)-C(8)-Ph alkynyl
group with the fourth position occupied by the hydrido
ligand. This latter atom has not been directly located
by this analysis, but its position (trans to the η2-alkyne
interaction) can be inferred from the NMR data and
from the arrangement of the heavy atoms. The Pt(2)-P
distances, 2.274(3) and 2.289(3) Å, fall in the range of
distances usually observed in Pt(II) phosphine com-
plexes.12b-f,15 The coordination of the alkynyl fragment
to Pt(2) causes, as expected, the reduction of the P(1)-
Pt(2)-P(2) angle to the value of 165.5(1)° due to the
lesser steric demand of the hydride ligand.
115(10)
a
Equivalent isotropic U defined as one-third of the trace of the
orthogonalized Uij tensor.
Ta ble 3. Selected In ter a tom ic Dista n ces (Å) a n d
An gles (d eg) for tr a n s,tr a n s,tr a n s-
{[P t(C6F 5)2(µ-η1:η2-CtCP h )2][P tH(P Et3)2]2}(4b)
Pt(1)-C(1)
Pt(2)-P(1)
Pt(2)-C(7)
C(7)-C(8)
2.068(9)
2.274(3)
2.443(10)
1.232(11)
Pt(1)-C(7)
Pt(2)-P(2)
Pt(2)-C(8)
C(8)-C(9)
1.984(8)
2.289(3)
2.265(10)
1.462(12)
The µ-η1:η2-C(7)-C(8)-Ph ligand is unsymmetrically
bonded to Pt(2) with the Câ atom closer to Pt(2) [Pt(2)-
C(8) ) 2.265(10) Å] than the CR atom [Pt(1)-C(7) )
2.443(10) Å]. This contrasts with the symmetrical π
linkage found in the dinuclear derivative cis,trans-[(CO)-
(C6F5)2Pt(µ-η1:η2-CtCPh)Pt(CtCPh)(PPh3)2] (7)17 and
suggests some degree of participation of the metal-
substituted vinylidene resonance structure B (Chart
2B), in addition to the dominant contribution of the
π-complex A (Chart 2A).2d,18
C(1)-Pt(1)-C(7)
P(1)-Pt(2)-C(7)
P(1)-Pt(2)-C(8)
C(7)-Pt(2)-C(8)
Pt(1)-C(7)-C(8)
Pt(2)-C(8)-C(7)
C(7)-C(8)-C(9)
87.7(3)
89.6(2)
99.5(2)
30.0(3)
169.1(8)
83.0(7)
P(1)-Pt(2)-P(2)
P(2)-Pt(2)-C(7)
P(2)-Pt(2)-C(8)
Pt(1)-C(7)-Pt(2)
Pt(2)-C(7)-C(8)
Pt(2)-C(8)-C(9)
165.5(1)
104.8(2)
92.1(2)
123.4(4)
66.9(6)
120.3(7)
156.6(11)
Ch a r t 2
In accord with this consideration, (i) the Pt(1)‚‚‚Pt(2)
distance of 3.904(2) Å is longer than that observed in
the related monoalkynyl bridged complex 717 and (ii)
the acetylenic skeleton Pt(1)-C(7)-C(8)-C(9) acquires
a cis-bent arrangement in such a way that the deviation
from linearity is more pronounced at Câ [C(7)-C(8)-
C(9) ) 156.6(11)°] than at the CR [Pt-C(7)-C(8) )
169.1(8)°]. As expected, the C(7)-C(8) vector is oriented
essentially perpendicular to the local coordination plane
of Pt(2) [the angle formed by the vector defined by Pt-
(2) and the midpoint of the CtC bond and the C(7)-
C(8) vector is 81.4(5)°] and is inclined by 1.01(8)° to this
(17) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.; Mart´ınez, F.; Urrio-
labeitia, E.; Welch, A. J . J . Chem. Soc., Dalton Trans. 1994, 1291.
(18) (a) Kolobova, N. E.; Skripkin, V. V.; Rozantseva, T. V.; Struch-
kov, Yu. T.; Aleksandrov, G. G.; Andrianov, V. G. J . Organomet. Chem.
1981, 218, 351. (b) Frank, K. G.; Selegue, J . P. J . Am. Chem. Soc. 1990,
112, 6414. (c) Akita, M.; Ishii, N.; Takabuchi, A.; Tanaka, M; Moro-
Oka, Y. Organometallics 1994, 13, 258 and references therein.

1824 Organometallics, Vol. 15, No. 7, 1996
Ara et al.
deoxygenated water (50 mL). The aqueous solution was
filtered and added dropwise to a solution of NBu4Br (0.570 g,
1.532 mmol) in water (10 mL), causing the precipitation of 1
as a white solid, which was filtered off, washed repeatedly with
deoxygenated water, and, finally, air dried (0.443 g, 87% yield).
Anal. Calcd for C60H82F10N2Pt: N, 2.30; C, 59.25; H, 6.79.
Found: N, 2.06; C, 58.96; H, 6.68. IR (cm-1): ν(CtC) 2077
(vs); ν(C6F5)X-sensitive 765 (s). 19F NMR (CD3COCD3): δ -111.5
(d, Fo, 3J Pt-Fo ) 415 Hz); -170.5 (t, Fp, 3J F-F ) 20.5 Hz); -168.5
(m, Fm). 13C NMR (CD3COCD3): δ 150-135 (br, C6F5); 132.0
(Cipso, Ph); 130.4, 126.8, 121.5 (s, Ph); 120.1 (s, Câ, platinum
satellites not observed); 103.9 (s, CR, platinum satellites not
observed); 58.0 (s, N-CH2, nBu); 23.2 (s, -CH2-, nBu); 19.0
(s, -CH2-CH3, nBu); 12.6 (s, CH3, nBu). ΛM (in acetone) )
plane [least-squares plane defined by Pt(2), P(1), P(2),
and the midpoint of C(7)-C(8)].
Con clu d in g Rem a r k s
As noted in the Introduction, metallo or elementa
(main group) substituted alkynyl substrates insert
easily into the Pt-H bond of [trans-PtH(PEt3)2(solvento)]+
to give cis addition complexes as the kinetic products.
It has been suggested that the first step in these
reactions, as well as in the insertion of alkynes into a
Pt-H bond of related complexes,19 is the formation of a
complex in which the CtC triple bond of the alkyne (or
alkynyl fragment) is η2-coordinated to the metal center.
In this context, the synthesis of the trinuclear complexes
4-6 is unexpected and the structure of 4b provides a
strong indication that such species exist. The dianionic
nature of the starting precursors [trans-Pt(C6F5)2-
(CtCR)2]2-, and perhaps the presence of C6F5 groups,
seems to be influential on the behavior of 1-3 as simple
3-platinapenta-1,4-diyne ligands toward the very reac-
tive species [trans-PtHL2(acetone)]+. However, it should
be noted that the influence of the electronic factor is
not clear. We have recently found20 that the reaction
between cis-[Pt(C6F5)2(CO)(THF)] (THF ) tetrahydro-
furan) and trans-[PtH(CtCPh(PPh3)2] affords the bi-
nuclear µ-phenylethenylidene complex [(OC)(C6F5)2Pt-
(µ-CtC(Ph)H)Pt(PPh3)2] (8). The formation of this
complex 8 could be the result of an initial alkynylation
of the cis-[Pt(C6F5)2(CO)] fragment and simultaneous
formation of a binuclear zwitterionic species cis,trans-
[(OC)(C6F5)2Pt-(µ-CtCPh)Pt+H(PPh3)2], which probably
evolves via cis,cis isomerization and cis 1,2 addition to
yield the final µ-phenylethenylidene complex 8.
182 Ω-1 cm2 mol-1
.
Complexes 2 and 3 were obtained similarly but using a
larger excess of LiCtCR (LiCtCR/Pt ) 8/1), and in the case
of 3, THF was used as solvent.
2: LinBu (2.36 M, 2.40 mL, 5.67 mmol), SiMe3CtCH (0.56
g, 5.67 mmol), trans-[Pt(C6F5)2(tht)2] (0.5 g, 0.7 mmol); 0.400g,
78% yield. Anal. Calcd for C54H90F10N2PtSi2: N, 2.32; C,
53.67; H, 7.51. Found: N, 2.27; C, 53.61; H, 8.07. IR (cm-1):
ν(CtC) 2014 (s, sh); ν(C6F5)X-sensitive 759 (s). 1H NMR (CDCl3):
δ -0.16 (s, SiMe3); 0.89 [t, -CH3, nBu]; 1.29 [m, -CH2, nBu];
1.59 [m, -CH2-, nBu]; 3.35 [m, NCH2, nBu]. 19F NMR
(CDCl3): δ -112.1 (d, Fo, 3J Pt-Fo ) 339 Hz); -169.8 (t, Fp, 3J F-F
) 19.3 Hz); -169.2 (m, Fm). 13C NMR (CD3COCD3, -50 °C):
δ 102.1 (s, CR or Câ); 57.3 (s, N-CH2, nBu); 22.7 (s, -CH2-,
nBu); 18.7 (s, -CH2-CH3, nBu); 12.5 (s, CH3, nBu); 0.81 (s,
SiMe3). ΛM (in acetone) ) 142 Ω-1 cm2 mol-1
.
3: LinBu (2.36 M, 1.83 mL, 4.31 mmol), BuCtCH (0.35 g,
4.31 mmol), trans-[Pt(C6F5)2(tht)2] (0.38 g, 0.54 mmol); 0.335
g, 90% yield. Anal. Calcd for C56H90F10N2Pt: N, 2.38; C, 57.18;
H, 7.71. Found: N, 2.20; C, 56.91; H, 8.01. IR (cm-1): ν(CtC)
2091 (vs); ν(C6F5)X-sensitive 756 (s). 1H NMR (CD3COCD3): δ 0.97
t
t
(s, Bu); 0.89 [t, -CH3, nBu]; 1.35 [m, -CH2, nBu]; 1.78 [m,
-CH2-, nBu]; 3.54 [m, NCH2, nBu]. 19F NMR (CD3COCD3):
3
3
δ -110.0 (d, Fo, J Pt-Fo ) 398 Hz); -171.8 (t, Fp, J F-F ) 19.5
Hz); -169.8 (m, Fm). 13C NMR (CD3COCD3): δ 107.5 (s, CR or
Exp er im en ta l Section
n
t
n
Câ); 59.2 (s, N-CH2, Bu); 33.4 (s, Bu); 24.3 (s, -CH2-, Bu);
19.8 (s, -CH2-Me, nBu); 13.4 (s, CH3, nBu). ΛM (in acetone)
All manipulations were performed under N2 atmosphere
using standard Schlenk techniques. All solvents were distilled
from appropriate drying agents. Elemental analyses of C, H,
and N and IR spectra were obtained as described elsewhere.7
1H, 19F, 13C, and 31P NMR spectra were recorded on either a
Varian XL-200 or a Bruker ARX 300 instrument. Chemical
shifts are reported in ppm relative to external standards
(SiMe4, CFCl3, and 85% H3PO4). Conductivities were mea-
sured in ca. 5 × 10-4 M acetone solutions using a Phillips 9501/
01 conductimeter, and mass spectra were obtained in a VG
Autospec spectrometer. Starting materials trans-[Pt(C6F5)2-
(tht)2]21 and trans-[PtHClL2] (L ) PPh3,13b PEt313c) were
prepared according to literature procedures. AgClO4 was
prepared by following a method previously described22 but
using Ag2CO3 as precursor.
P r ep a r a tion of (NBu 4)2[tr a n s-P t(C6F 5)2(CtCR)2] (R )
P h (1), SiMe3 (2), tBu (3)). A typical preparation for complex
1 was as follows: A solution of LinBu in hexane (2.36 M, 1.47
mL, 3.47 mmol) was added dropwise during 5 min to a diethyl
ether solution (30 mL) of PhCtCH (0.36 g, 3.48 mmol) at -10
°C. After 20 min of stirring, trans-[Pt(C6F5)2(tht)2] (0.491 g,
0.696 mmol) was added and the mixture stirred for 24 h at
room temperature. The resulting white suspension was
evaporated to dryness, and the residue was treated with
) 169 Ω-1 cm2 mol-1
.
P r ep a r a tion of tr a n s,tr a n s,tr a n s-{[P t(C6F 5)2(µ-η1:η2-
CtCP h )2](P tHL2)2} (L ) P P h 3 (4a ), P Et3 (4b)). To a
filtered solution of 0.198 mmol of [trans-PtH(PPh3)2(acetone)]-
(ClO4) (prepared from 0.15 g (0.198 mmol) of trans-[PtHCl-
(PPh3)2] and AgClO4 (0.041 g, 0.198 mmol) in 30 mL of acetone)
was added 0.115 g (0.095 mmol) (0.95 molar equiv) of 1, giving
a deep yellow solution. After 10 min of stirring at room
temperature, a yellow solid precipitated. The mixture was
stirred for 30 min and then concentrated to ca. 10 mL. The
solid was filtered off, washed with acetone (1 mL), and air dried
(0.119 g, 58% yield). Anal. Calcd for C100H72F10P4Pt3: C,
55.28; H, 3.34. Found: C, 54.96; H, 3.69. IR (cm-1): ν(Pt-
H) 2145 (s); ν(CtC) 1932 (vs); ν(C6F5)X-sensitive, this absorption
can not be assigned unambiguously. FAB mass spectrum:
1
molecular peak not observed, m/z 719, [Pt(PPh3)2]+, 100%. H
NMR (CDCl3): δ 7.27 (m, 60 H, PPh3); 6.70 (t, 2 Hp, Ph), 6.44
1
(t, 4 Hm, Ph); 5.70 (d, 4 Ho, Ph); -9.08 (t, 2 H, Pt-H, J Pt-H
)
1088 Hz, J P-H ) 13.4 Hz). 19F NMR (CDCl3): δ -109.2 (d,
2
Fo, J Pt-Fo ) 351 Hz); -165.7 (m, Fp and Fm). 31P NMR
3
1
(CDCl3): δ 24.11 (s, J Pt-P ) 2986 Hz).
Using a similar procedure, the reaction between trans-
[PtHCl(PEt3)2] (0.120 g, 0.256 mmol), AgClO4 (0.053 g, 0.256
mmol), and (NBu4)2[trans-Pt(C6F5)2(CtCPh)2] (0.148 g, 0.122
mmol) gave 4b as a yellow solid (0.101 g, 52% yield). Anal.
Calcd for C52H72F10P4Pt3: C, 39.13; H, 4.55. Found: C, 39.46;
H, 4.60. IR (cm-1): ν(Pt-H) 2151 (s); ν(CtC) 1989 (m), 1949
(vs). FAB mass spectrum: molecular peak not observed, m/z
431, [Pt(PEt3)2]+, 100%. 1H NMR (CDCl3): δ 7.29, 7.10 (m,
10 H, Ph); 1.64 (m, 24 H, CH2, PEt3), 0.95 (m, 36 H, CH3, PEt3);
(19) (a) Attig, T. G.; Clark, H. C.; Wong, C. S. Can. J . Chem. 1977,
55, 189. (b) Clark, H. C.; J ablonski, C. R.; Wong, C. S. Inorg. Chem.
1975, 14, 1332. (c) Clark, H. C.; Wong, C. S. J . Organomet. Chem. 1975,
92, C31.
(20) Ara, I.; Berenguer, J . R.; Fornie´s, J .; Lalinde, E.; Toma´s, M.
Organometallics, in press.
(21) Uso´n, R.; Fornie´s, J .; Mart´ınez, F.; Toma´s, M. J . Chem. Soc.,
Dalton Trans. 1980, 888.
(22) Smith, G. F.; Ring, F. J . Am. Chem. Soc. 1937, 59, 1889.
1
2
-9.6 (t, 2 H, Pt-H, J Pt-H ) 1255 Hz, J P-H ) 13.5 Hz). 19F

Trinuclear Platinum Hydride Complexes
Organometallics, Vol. 15, No. 7, 1996 1825
3
t
NMR (CDCl3): δ -113.0 (d, Fo, J Pt-Fo ) 346 Hz; -166.8 (t,
PEt3); 0.98 (m, 36 H, CH3, PEt3); 0.84 (s, 18 H, Bu); -9.90 (t,
Fp, 3J F-F ) 20 Hz); -166.1 (m, Fm). 31P NMR (CDCl3): δ 20.44
2 H, Pt-H, J Pt-H ) 1147 Hz, J P-H ) 13.5 Hz). 19F NMR
(CDCl3): δ 112.5 (d, Fo, J Pt-Fo ) 378 Hz); -168.2 (t, Fp, J F-F
) 20.3 Hz; -167.1 (m, Fm). 31P NMR (CDCl3): δ 19.48 (s, J Pt-P
) 2708 Hz).
2
1
3
3
(s, J Pt-P ) 2640 Hz).
P r ep a r a tion of tr a n s,tr a n s,tr a n s-{[P t(C6F 5)2(µ-η1:η2-
CtCSiMe3)2](P tHL2)2} (L ) P P h 3 (5a ), P Et3 (5b)). To an
acetone solution (40 mL) of trans-[PtHCl(PPh3)2] (0.222 g, 0.29
mmol) was added 0.060 g (0.290 mmol) of AgClO4, and the
mixture was stirred at room temperature for 1 h. The
resulting AgCl was removed by filtration through Celite, and
the filtrate was concentrated to ca. 15 mL and cooled to -10
°C. Then, 0.178 g (0.140 mmol) of 2 was added, resulting in
the formation of a yellow solution. The mixture was stirred
for 20 min, and the white solid formed was filtered off and
recrystallized from CH2Cl2/hexane. Under these conditions 5a
crystallizes with one molecule of CH2Cl2 (observed by 1H NMR)
(0.038 g, 12% yield). Anal. Calcd for C95H82F10P4Pt3Si2Cl2: C,
50.71; H, 3.67. Found: C, 50.75; H, 3.19. IR (cm-1): ν(Pt-
H) 2160 (m); ν(CtC) 1872 (sh), 1836 (s, br). FAB mass
spectrum: molecular peak not observed, m/z 719, [Pt(PPh3)2]+,
100%. 1H NMR (CDCl3): δ 7.52 (m, 24 H, Ph, PPh3); 7.38 (m,
36 H, Ph, PPh3); -1.09 (s, 18 H, SiMe3); -10.39 (t, 2 H, Pt-H,
X-r a y Cr yst a l St r u ct u r e Det er m in a t ion of tr a n s,-
tr a n s,tr a n s-{[P t(C6F5)2(µ-η1:η2-CtCP h )2][P tH(P Et3)2]2} (4b).
Single crystals of 4b in the form of pale yellow plates were
obtained by slow diffusion of n-hexane into a CHCl3 solution
of the bulk solid at room temperature. A representative crystal
was fixed with epoxy on top of a glass fiber and transferred to
the cold gas stream (200 K) of a Siemens STOE/AED2 four-
circle diffractometer (graphite-monochromated Mo KR radia-
tion). Cell constants were obtained from setting angles of 25
carefully measured reflections in the range 20 < 2θ < 28°. Data
were collected by the ω/2θ method in the range 4 < 2θ < 47°.
Three check reflections, measured after every 360 min of beam
exposure, showed no systematic variations in decay. Data
were corrected for Lorentz and polarization effects. An
absorption correction based on ψ-scans (9 reflections) was
applied, with transmission factors of 1.000 and 0.498. The
structure was solved by the heavy-atom method, which
revealed the positions of the Pt atoms. The remaining non-
hydrogen atoms were located in succeeding difference Fourier
syntheses and subjected to anisotropic full-matrix least-
squares refinement. One of the C atoms, C(16), was found to
be disordered at half-occupacy over two sites. Hydrogen atoms
were included at calculated positions (C-H ) 0.96 Å). A total
of 2999 reflections with I > 2σIo were used to refine 324
parameters. Final residuals were R ) 0.0325 and wR )
0.0437. The highest peaks in the final difference map (e1.15
e Å-3) are close to one of the Pt atoms and have no chemical
significance.
1J Pt-H ) 1088.6 Hz, J P-H ) 13.5 Hz). 19F NMR (CDCl3): δ
2
-111.5 (dm, Fo, J Pt-Fo ) 360 Hz); -165.2 (m, Fp and Fm). 31P
3
1
NMR (CDCl3): δ 22.90 (s, J Pt-P ) 3006 Hz).
Complex 5b was prepared by following a similar procedure
using trans-[PtHCl(PEt3)2] (0.161 g, 0.344 mmol), AgClO4 (0.07
g, 0.344 mmol), and 2 (0.200 g, 0.165 mmol) as starting
materials. The white solid was not recrystallized (0.052 g, 20%
yield). Anal. Calcd for C46H80F10P4Pt3Si2: C, 34.78; H, 5.07.
Found: C, 35.05; H, 5.22. IR (cm-1): ν(Pt-H) 2148 (s); ν(CtC)
1886 (vs). FAB mass spectrum: m/z 1587 ([M]+, 20%), 1420
([M - C6F5]+, 15%), 1009 ([Pt2(C6F5)(PEt3)3(CtCSiMe3)]+,
51%), 890 ([Pt2(C6F5)(PEt3)2(CtCSiMe3)]+, 47%), 695 ([Pt-
(C6F5)(PEt3)2(CtCSiMe3)]+, 54%), 597 ([Pt(C6F5)(PEt3)2]+, 90%),
431 ([Pt(PEt3)2]+, 100%). 1H NMR (CDCl3): δ 1.67 (m, 24 H,
CH2, PEt3), 0.94 (m, 36 H, CH3, PEt3); -0.13 (s, 18 H, SiMe3),
All calculations were performed on a local area VAX cluster
(VAX/VMS V5.5) with the Siemens SHELXTL PLUS software
package.23
-11.12 (t, 2 H, Pt-H, J Pt-H ) 1249 Hz, J P-H ) 13.6 Hz). 19F
1
2
3
NMR (CDCl3): δ -113.2 (dm, Fo, J Pt-Fo ) 371 Hz; -167.4 (t,
Ack n ow led gm en t. We thank the Comisio´n Inter-
ministerial de Ciencia y Tecnolog´ıa (Spain; Project PB
92-0364) for financial support and for a grant (to J .R.B.).
E.L. and M.T.M. thank the Instituto de Estudios Rio-
janos for financial support.
Fp, 3J F-F 19.9 Hz); -166.7 (m, Fm). 31P NMR (CDCl3): δ 19.80
1
(s, J Pt-P ) 2683 Hz).
P r ep a r a tion of tr a n s,tr a n s,tr a n s-{[P t(C6F 5)2(µ-η1:η2-
CtCtBu )2][P tH(P Et3)2]2} (6b). To a cooled (-10 °C) solution
(4 mL) of [trans-PtH(PEt3)2(acetone)](ClO4), prepared from
0.200 g (0.428 mmol) of trans-[PtHCl(PEt3)2] and AgClO4
(0.089 g, 0.428 mmol) in acetone (40 mL), was added an
acetone solution (5 mL) of 3 (0.201 g, 0.171 mmol). The
mixture was stirred for 15 min, and then the resulting yellow
solid was filtered off, washed with cold acetone (1 mL,
-20 °C), and air dried (0.101 g, 38% yield). Anal. Calcd for
Su p p or tin g In for m a tion Ava ila ble: Tables of anisotro-
pic thermal parameters, hydrogen atom positional parameters
and U values, and complete bond lengths and angles for 4b (4
pages). Ordering information is given on any current mast-
head page.
C
48H80F10P4Pt3: C, 37.04; H, 5.18. Found: C, 36.70; H, 5.15.
OM950827F
IR (cm-1): ν(Pt-H) 2147 (s); ν(CtC) 1955 (s, br). FAB mass
spectrum: molecular peak not observed, m/z 593 ([Pt(CtCt-
Bu)2(PEt3)2]+, 38%), 511 ([Pt(CtCtBu)(PEt3)2]+, 35%), 431 ([Pt-
(PEt3)2]+, 100%). 1H NMR (CDCl3): δ 1.70 (m, 24 H, CH2,
(23) SHELXTL-PLUS, Software Package for the Determination of
Crystal Structures, Release 4.0; Siemens Analytical X-ray Instruments,
Inc.: Madison, WI, 1990.