Rearrangement or C-H activation processes promoted by reaction with the solvate [cis-Pt(C6F5)2(thf)2]

Article abstract of DOI:10.1021/om060977y

A new series of functionalized (μ-hydride)(μ-acetylide) isomeric derivatives [trans-(PPh₃)(C₆F₅)Pt(μ-H)(μ- 1κC^α:η²-C≡CR)Pt(C₆F ₅)(PPh₃) (3) and [cis,cis-(PPh₃) ₂Pt(μ-H)(μ-1κC^α:η²- C≡CR)Pt(C₆F₅)₂] (4) (R = (4-CH ₃)C₆H₄, a; (4-CN)C₆H₄, b; CMe=CH₂, c; C(OH)Me₂, d; C(OH)EtMe, e; C(OH)Ph ₂, f) have been prepared by reaction in mild conditions of the disolvated [cis-Pt(C₆F₅)₂(thf)₂] with the corresponding Pt(II) [trans-PtH(C≡CR)(PPh₃) ₂] (1) or Pt(0) [Pt(η²-HC≡CR)(PPh ₃)₂] (2) isomers. The course of these reactions seems to be rather general, but in the case of the diphenylhydroxy precursors is strongly influenced by an easy gem (4f) to trans (3f) isomerization and the presence of water, which leads to the formation of the unexpected (μ-hydroxy)(μ-vinyl) complex [cis,cis-(PPh₃)₂Pt{μ-1κC ^α:η²-CH=CHC(OH)Ph₂}(μ-OH)Pt(C ₆F₅)₂] (5f). Control of the latter reaction has allowed us to detect the mixed-valence intermediate [cis,cis-(PPh ₃)₂Pt{μ-η²:η²- HC≡C(OH)Ph₂}Pt(C₆F₅)₂(thf)] (6f). Starting from [Pt(η²-HC≡C₅H ₄N-4)(PPh₃)₂] (2g) and [cis-Pt(C ₆F₅)₂(thf)₂] only the trinuclear mixed-valence adduct [{(PPh₃)₂Pt(μ-η²: 2κN-HC≡C₅H₄N-4)}₂{cis-Pt(C ₆F₅)₂}] (7g) is obtained.

Full text of DOI:10.1021/om060977y

Organometallics 2007, 26, 1161-1172
1161
Rearrangement or C-H Activation Processes Promoted by Reaction
with the Solvate [cis-Pt(C6F5)2(thf)2]
Jesu´s R. Berenguer, Mar´ıa Bernechea, and Elena Lalinde*
Departamento de Qu´ımica, Grupo de S´ıntesis Qu´ımica de La Rioja, UA-CSIC,
UniVersidad de La Rioja, 26006, Logron˜o, Spain
ReceiVed October 24, 2006
A new series of functionalized (µ-hydride)(µ-acetylide) isomeric derivatives [trans-(PPh3)(C6F5)Pt(µ-
H)(µ-1κCR:η2-CtCR)Pt(C6F5)(PPh3)] (3) and [cis,cis-(PPh3)2Pt(µ-H)(µ-1κCR:η2-CtCR)Pt(C6F5)2] (4) (R
) (4-CH3)C6H4, a; (4-CN)C6H4, b; CMedCH2, c; C(OH)Me2, d; C(OH)EtMe, e; C(OH)Ph2, f) have
been prepared by reaction in mild conditions of the disolvated [cis-Pt(C6F5)2(thf)2] with the corresponding
Pt(II) [trans-PtH(CtCR)(PPh3)2] (1) or Pt(0) [Pt(η2-HCtCR)(PPh3)2] (2) isomers. The course of these
reactions seems to be rather general, but in the case of the diphenylhydroxy precursors is strongly influenced
by an easy gem (4f) to trans (3f) isomerization and the presence of water, which leads to the formation
of the unexpected (µ-hydroxy)(µ-vinyl) complex [cis,cis-(PPh3)2Pt{µ-1κCR:η2-CHdCHC(OH)Ph2}(µ-
OH)Pt(C6F5)2] (5f). Control of the latter reaction has allowed us to detect the mixed-valence intermediate
[cis,cis-(PPh3)2Pt{µ-η2:η2-HCtC(OH)Ph2}Pt(C6F5)2(thf)] (6f). Starting from [Pt(η2-HCtC5H4N-4)(PPh3)2]
(2g) and [cis-Pt(C6F5)2(thf)2] only the trinuclear mixed-valence adduct [{(PPh3)2Pt(µ-η2:2κN-HCtC5H4N-
4)}2{cis-Pt(C6F5)2}] (7g) is obtained.
C-H activation, the (µ-hydride)(µ-alkynyl) diplatinum complex
[cis,cis-(PPh3)2Pt(µ-H)(µ-1κCR:η2-CtCPh)Pt(C6F5)2],22 while
the reaction of the same solvate substrate [cis-Pt(C6F5)2(thf)2]
with the hydride-alkynyl platinum(II) complex [trans-PtH-
(CtCPh)(PPh3)2] leads, also under very mild reaction condi-
tions, to the (µ-hydride)(µ-alkynyl) diplatinum isomer [trans-
(PPh3)(C6F5)Pt(µ-H)(µ-1κCR:η2-CtCPh)Pt(C6F5)(PPh3)].22,23 Al-
though many different structural types of dimeric hydride-
bridged platinum complexes have been reported,23-27 these two
acetylide-bridged diplatinum isomers belong to a rare class of
these compounds, which contains mixed bridging systems
consisting of a hydride and a hydrocarbon ligand. In fact,
as far as we are aware, the only other reported examples are
the analogous cationic (µ-alkylidene)(µ-hydride) complexes
[Pt2(L-L)2(µ-CHCH2Ar)(µ-H)]+ 28-31 and the cationic (µ-hy-
dride)(µ-carbonyl) or (µ-hydride)(µ-isocyanide) derivatives
[Pt2(L-L)2(µ-CX)(µ-H)]+ (X ) O32,33 or NR33), which are
Introduction
The use of transition metal complexes to activate carbon-
hydrogen bonds has become one of the most pursued goals of
organometallic chemistry.1-5 Nowadays, the activation of C-H
bonds in alkynes is one of the most active fields of research in
this area, mainly due to their implications in the alkyne/
vinylidene tautomerization, as well as in some catalytic
processes.6-21 In this context, we have recently reported that
[cis-Pt(C6F5)2(thf)2] reacts with the alkyne platinum(0) derivative
[Pt(η2-HCtCPh)(PPh3)2] to yield, through an unexpectedly easy
* Corresponding author. E-mail: elena.lalinde@dq.unirioja.es.
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10.1021/om060977y CCC: $37.00 © 2007 American Chemical Society
Publication on Web 02/01/2007

1162 Organometallics, Vol. 26, No. 5, 2007
Berenguer et al.
formally diplatinum(I) species. Our research group has also
reported the (µ-H)(µ-C6F5) platinum(II) derivative [trans-{Pt-
(C6F5)(PPh3)}2(µ-H)(µ-C6F5)], generated through an initial
adduct stabilized by a mixed (µ-H)(µ-κP:η2-PPh3) bridging
system, by reaction of [trans-PtH(C6F5)(PPh3)2] with [cis-Pt-
(C6F5)2(thf)2].23
Nevertheless, the course of the formation of the (µ-hydride)-
(µ-alkynyl) diplatinum(II) isomers can be influenced by the
nature of the substituent at the alkynyl or alkyne ligands in the
mononuclear substrates. Thus, we have observed that the
reaction of [cis-Pt(C6F5)2(thf)2] with the pyridylacetylide com-
plex [trans-PtH(CtC5H4N-2)(PPh3)2] affords the initial ad-
duct [trans,cis-(PPh3)2HPt(µ-1κCR:η2R,â:2κN-CtC5H4N-2)Pt-
(C6F5)2], which finally rearranges to form a tetranuclear platinum
cluster containing both an edge-bridging alkynyl group and a
face-capping vinyl ligand.34
These results prompted us to investigate the influence of the
functionalized substituents (R) at the alkynyl or alkyne ligand,
and we present here a systematic study of the reactivity of
several alkyne Pt(0) [Pt(η2-HCtCR)(PPh3)2] and alkynyl
Pt(II) [trans-PtH(CtCR)(PPh3)2] isomers (R ) (4-CH3)C6H4,
(4-CN)C6H4, CMe2dCH2, C(OH)Me2, C(OH)EtMe, C(OH)Ph2,
C5H4N-4) toward the disolvated substrate [cis-Pt(C6F5)2(thf)2].
This work has allowed us to obtain a good number of new
functionalized (µ-hydride)(µ-alkynyl) diplatinum complexes.
In addition, we also report the isolation of an unexpected
(µ-hydroxy)(µ-vinyl) diplatinum derivative in the reaction with
the R-diphenylpropinol Pt(0) complex.
Figure 1. ORTEP view of [trans-PtH{CtC(4-CN)C6H4}(PPh3)2]
(1b). Ellipsoids are drawn at the 50% probability level. Aromatic
hydrogen atoms have been omitted for clarity.
Table 1. Selected Bond Lengths (Å) and Angles (deg) for
[trans-PtH{CtC(4-CN)C6H4}(PPh3)2] (1b)a
Pt(1)-C(1) 2.018(5) Pt(1)-P(1) 2.2732(8) Pt(1)-H(1) 1.68(9)
C(1)-C(2) 1.224(7) C(2)-C(3) 1.425(6)
C(1)-Pt(1)-P(1)
C(1)-Pt(1)-H(1) 180.000(12) Pt(1)-C(1)-C(2)
C(1)-C(2)-C(3) 180.000(1)
95.60(2)
P(1)-Pt(1)-P(1)’ 168.81(4)
180.0
a Symmetry transformations used to generate equivalent atoms (′): -x
+ 1, y, -z + 1/2.
Results and Discussion
Scheme 1
With the aim of completing a series of alkynyl Pt(II) and
alkyne Pt(0) mononuclear isomers containing vinyl, propargyl,
or functionalized aryl groups as radicals in the alkynylic rest
(tC-R), we have synthesized, following previously re-
ported synthetic strategies,35 the precursors [trans-PtH(CtCR)-
(PPh3)2] (1) and [Pt(η2-HCtCR)(PPh3)2] (2) (R ) (4-CH3)-
C6H4, a; (4-CN)C6H4, b; CMedCH2, c; C(OH)Me2, d; C(OH)-
EtMe, e; C(OH)Ph2, f; C5H4N-4, g), from which 1a, 1b, and
2b are new complexes. We have not been able to obtain the
pyridyl-acetylide complex [trans-PtH(CtCC5H4N-4)(PPh3)2]
from the corresponding [trans-PtHCl(PPh3)2]/HCtCPy/NEt3
system, but the new Pt(0) isomer [Pt(η2-HCtCC5H4N-4)-
(PPh3)2] (2g) can be easily obtained by reaction of [Pt(C2H4)-
(PPh3)2] with HCtCPy (see Supporting Information). The
complete characterization of these new compounds, as well as
the spectroscopic data of the alkyne derivatives 2a, 2d, and 2e,
are collected in the Supporting Information. For complex 1b
(R ) (4-CN)C6H4), an X-ray diffraction structural analysis has
been also carried out (Figure 1 and Table 1), with the aim of
observing a possible intermolecular interaction between the
cyanide group of the acetylide and the hydride ligand. Unfor-
tunately, although the hydride (H(1)) has been located from
difference maps, the distance H(1)‚‚‚N(1)C-C6H4 (4.255 Å) is
too long to suggest the existence of any kind of interaction.
The rest of the structural features of the structure of complex
1b are similar to those described for other mononuclear
hydride-alkynyl platinum(II) complexes.36,37
Reaction of [cis-Pt(C6F5)2(thf)2] with [trans-PtH(CtCR)-
(PPh3)2] (1a-e) and [Pt(η2-HCtCR)(PPh3)2] (2a-e). As is
shown in Scheme 1 (i), the reaction of [trans-PtH(CtCR)-
(PPh3)2] (1a-e) with [cis-Pt(C6F5)2(thf)2] (after 30 min) causes
a complex ligand rearrangement, yielding the dinuclear (µ-
hydride)(µ-acetylide) complexes [trans-(PPh3)(C6F5)Pt(µ-H)(µ-
1κCR:η2-CtCR)Pt(C6F5)(PPh3)] (3a-e, “trans”-type) in high
yield (50-80%). On the other hand, treatment of the alkyne
substrates [Pt(η2-HCtCR)(PPh3)2] (2a-e) with an equimo-
lecular amount of [cis-Pt(C6F5)2(thf)2] (Scheme 1, ii) results in
C-H activation to generate the “gem”-type (µ-hydride)(µ-
acetylide) isomers [cis,cis-(PPh3)2Pt(µ-H)(µ-1κCR:η2-CtCR)-
Pt(C6F5)2] (4a-e) in moderate to good yields (50-66%, except
for 4c, 12%). It must be noted that, in spite of the presence of
oxygen or nitrogen atoms or vinylic groups on the functionalized
radicals of the alkynylic rest (tC-R), the course of the reaction
is the same as that previously described for the phenylacetylide-
or phenylalkyne-related precursors.22,23 In particular, it is
remarkable that in all the cases the activation reaction of the
(34) Berenguer, J. R.; Eguiza´bal, E.; Falvello, L. R.; Fornie´s, J.; Lalinde,
E.; Mart´ın, A. Organometallics 1999, 18, 1653.
(35) Furlani, A.; Licoccia, S.; Russo, M. V.; Chiesi-Villa, A.; Guastini,
C. J. Chem. Soc., Dalton Trans. 1982, 2449.
(36) Ara, I.; Berenguer, J. R.; Eguiza´bal, E.; Fornie´s, J.; Go´mez, J.;
Lalinde, E.; Saez-Rocher, J. M. Organometallics 2000, 19, 4385, and
references therein.
(37) Russo, M. V.; Furlani, A.; Licoccia, S.; Paolesse, R.; Chiesi-Villa,
A.; Guastini, C. J. Organomet. Chem. 1994, 469, 245.

Rearrangement Promoted by the SolVate [cis-Pt(C6F5)2(thf)2]
Organometallics, Vol. 26, No. 5, 2007 1163
alkyne C-H bond occurs at room temperature within seconds,
except for the 1-cyano-4-ethynylbenzene complex 4b, the
formation of which takes about 24 h to complete. Probably, in
this case, the presence of the nitrogen atom of the cyano-phenyl
group influences the course of the reaction. Nevertheless, the
study of the evolution of the reaction mixture by multinuclear
NMR spectroscopy at room temperature shows only signals due
to the corresponding precursors and the final diplatinum complex
4b during the course of the reaction. At the end, when the alkyne
precursor 2b has been consumed (within 24 h), the NMR spectra
additionally show signals due to OPPh3 and other unidentified
decomposition products. It should be noted that the “gem”-type
complexes 4, which are stable in solution at room temperature,
isomerize to the “trans”-type derivatives 3 by prolonged heating
in acetone or toluene (ca. 20 or 2 h, respectively), although with
considerable decomposition. This fact seems to suggest that the
“trans”-type complexes are probably the most stable thermo-
dynamic species, but their formation starting from [trans-PtH-
(CtCR)(PPh3)2] does not occurs through the “gem”-type
derivatives (4) as intermediates. Moreover, complexes 4a-e are
more insoluble than complexes 3a-e, which precludes the
recording of their 13C{1H} NMR spectra.
Complexes 3a-e and 4a-e have been characterized by the
usual analytical and spectroscopic means (see Experimental
Section and Supporting Information). In addition, the structures
of complexes 3a, 3b, 4a, 4c, and 4e have been confirmed by
single-crystal X-ray diffraction. All the complexes present
structural features in the solid state similar to those observed
for the phenylethynyl-related complexes.22,23 Figure 2 shows
the structures of a “trans”- (3b) and a “gem”-type (4a) complex
as representative examples, which have been chosen because
the hydride ligands have been located directly from the final
difference Fourier map (selected bond distances and angles are
shown in Table 2 and details for 3a, 4c, and 4e derivatives can
be found in Figure S1 and Tables S1 and S2 in the Supporting
Information). In both complexes 3b and 4a, the hydride ligand
is bonded in an essentially symmetrical way to both platinum
centers, the Pt-H distances (Pt(1)-H(1) 1.83(6) Å 3b, 1.63(8)
Å 4a; Pt(2)-H(1) 1.72(6) Å 3b, 1.61(8) Å 4a), as well as the
Pt-Pt-H angles (Pt(1)-Pt(2)-H(1) 38.2(18)° 3b, 29(3)° 4a;
Pt(2)-Pt(1)-H(1) 35.6(18)° 3b, 28(3)° 4a), being identical
within experimental error, although some difference could be
expected due to the different trans influence of the C6F5 and
PPh3 ligands. The hydride is coordinated essentially trans to
the ipso-carbon atom, C(1), of one C6F5 group (C(1)-Pt(2)-
H(1) 160.1(18)° 3b, 167(3)° 4a) and to the phosphorus atom
P(1) (P(1)-Pt(1)-H(1) 168.1(18)° 3b, 169(3)° 4a).
Although the distribution of the PPh3 and C6F5 ligands is
different in both types of complexes, all derivatives (3a, 3b,
4a, 4c, and 4e) show a roughly planar central core formed by
the platinum and phosphorus atoms, the acetylenic carbons, and
the ipso-C atoms of the C6F5 rings (for complexes 3b and 4a,
the hydride ligand also lies in this plane), with the alkynyl ligand
σ-bonded to Pt(1) (Pt(1)-C(13) 1.935(15)-2.024(10) Å) and
unsymmetrically π-bonded to Pt(2) (Pt(2)-C(13) 2.186(5)-
2.249(7) Å, Pt(2)-C(14) 2.286(5)-2.325(6) Å). The presence
of the bridging hydride ligand causes a remarkable dissimilarity
in the angles around the Pt centers. The angles P(1)-Pt(1)-
Pt(2) (141.57(4)-157.92(6)°) and C(1)-Pt(2)-Pt(1) (160.96-
(14)-167.2(4)°) are substantially larger than the corresponding
angles P(2)-Pt-Pt (108.71(3)-112.88(5)°) and C(7)-Pt-Pt
(110.3(2)-112.49(13)°), thus reflecting a considerable bending
of both P(2)Ph3 and C6F5 (with C(7)) ligands toward the less
sterically demanding bridging hydride ligand. The Pt-Pt
Figure 2. Molecular structures of (a) [trans-(PPh3)(C6F5)Pt-
(µ-H){µ-1κCR:η2-CtC(4-CN)C6H4}Pt(C6F5)(PPh3)] (3b) and (b)
[cis,cis-(PPh3)2Pt(µ-H){µ-1κCR:η2-CtC(4-CH3)C6H4}Pt(C6F5)2] (4a).
Ellipsoids are drawn at the 50% probability level. Hydrogen atoms
have been omitted for clarity.
distances (2.8293(5)-2.8459(3) Å) compare to those found in
the phenylethynyl-related complexes22,23 and in other 30e-
diplatinum hydride species containing mixed (µ-H)(µ-X) bridg-
ing systems38,39 and are in accordance with theoretical calcula-
tions that suggest the existence of a through-ring platinum-
platinum bonding interaction.40
Although the hydride ligand has not been located in the
structures of complexes 3a, 4c, and 4e, the proton NMR spectra
of all complexes show the expected hydride resonance as a
doublet of doublets (between -7.11 (4b) and -7.68 (3d) ppm)
with two different sets of 195Pt satellites, in accordance with its
bridging nature, as can be seen in Figure 3, as an illustrative
example. In both types of complexes (3 and 4) the highest
(38) van Leeven, P. W. N. M.; Roobeek, C. F.; Frijns, J. H. G.; Orpen,
A. G. Organometallics 1990, 9, 1211.
(39) Leoni, P.; Manetti, S.; Pascuali, M. Inorg. Chem. 1995, 34, 749.
(40) Aullo´n, G.; Alemany, P.; Alvarez, S. J. Organomet. Chem. 1994,
478, 75.

1164 Organometallics, Vol. 26, No. 5, 2007
Berenguer et al.
Table 2. Selected Bond Lengths (Å) and Angles (deg) for
[trans-(PPh3)(C6F5)Pt(µ-H){µ-1KCr:η2-CtC(4-CN)C6H4}-
Pt(C6F5)(PPh3)] (3b) and [cis,cis-(PPh3)2Pt(µ-H)-
{µ-1KCr:η2-CtC(4-CH3)C6H4}Pt(C6F5)2]‚CH2Cl2‚H2O
(4a‚CH2Cl2‚H2O)
splits into a doublet by the large expected coupling to the trans
bridging hydride (2JP1-H ) 75 Hz). For the “gem”-type
complexes 4 (Figure 4c) the signals, which exhibit two sets of
platinum satellites, have tentatively been assigned in accordance
with the solid-state structures. Thus, the doublet with the bigger
3b
4a‚CH2Cl2‚H2O
1
2
coupling constants (δ 13.2-11.0, JP1-Pt1 ≈ 3300 Hz, JP1-Pt2
) 61.4-51.3 Hz) is assigned to the phosphorus atom P1, with
the bigger angle P(1)-Pt(1)-Pt(2) (∼145°), while the other
Pt(1)-C(13)
Pt(1)-P(1)
Pt(2)-P(2)
Pt(1)-Pt(2)
Pt(1)-H(1)
Pt(2)-C(1)
Pt(1)-C(7)
Pt(2)-C(13)
Pt(2)-C(14)
Pt(2)-H(1)
C(13)-C(14)
1.984(5)
2.2622(12)
2.2521(13)
2.8409(3)
1.83(6)
2.039(5)
2.053(5)
2.230(5)
2.286(5)
1.72(6)
1.989(6)
2.2923(15)
2.3181(17)
2.8459(3)
1.63(8)
2.034(7)
2.043(7)
2.186(5)
2.325(6)
1.61(8)
Pt(1)-P(2)
Pt(2)-C(7)
1
2
signal (δ 13.1-11.0, JP2-Pt1 ) 2810-2696 Hz, JP2-Pt2
)
58.6-47.0 Hz) has been attributed to P(2) (P(2)-Pt(1)-Pt(2)
≈ 112°).
Reaction of [cis-Pt(C6F5)2(thf)2] with [trans-PtH{CtC-
(OH)Ph2}(PPh3)2] (1f) and [Pt{η2-HCtC(OH)Ph2}(PPh3)2]
(2f). The disolvate [cis-Pt(C6F5)2(thf)2] reacts with the mono-
nuclear complexes derived from 1,1-diphenyl-2-propyn-1-ol
[trans-PtH{CtC(OH)Ph2}(PPh3)2] (1f) and [Pt{η2-HCtC(OH)-
Ph2}(PPh3)2] (2f) in a different way (Scheme 2). As has been
shown,36 the hydride-acetylide complex 1f has still not been
prepared as a pure complex; it is always accompanied by
variable amounts of the Pt(0) isomer 2f. Thus, a mixture
containing the Pt(II) alkynyl 1f and the Pt(0) alkyne 2f substrates
(80/20 molar ratio, respectively) was reacted with an equimo-
lecular amount of [cis-Pt(C6F5)2(thf)2] at room temperature
(Scheme 2, i), and the reaction was studied by 31P{1H} NMR.
As expected, the orange solution obtained after 2 min consisted
of a mixture of the dinuclear (µ-hydride)(µ-acetylide) isomers
[trans-(PPh3)(C6F5)Pt(µ-H){µ-1κCR:η2-CtCC(OH)Ph2}Pt(C6F5)-
(PPh3)] (3f, “trans”-type) and [cis,cis-(PPh3)2Pt(µ-H){µ-1κCR:
η2-CtCC(OH)Ph2}Pt(C6F5)2] (4f, “gem”-type), from which pure
complex 3f can be isolated as a white complex with moderate
yield (42%). However, it must be noted that the molar ratio
observed in the reaction mixture (3f:4f, 85:15 vs 1f:2f, 80:20)
indicates that the “gem”-type isomer 4f probably isomerizes to
some extent to the “trans”-type 3f. As has been mentioned, this
kind of process has been observed in complexes 4a-e but only
at high temperature and with a considerable decomposition. The
confirmation of this mild isomerization process was obtained
in the study by 31P{1H} NMR of the reaction at room
temperature between the corresponding equimolecular amounts
of [cis-Pt(C6F5)2(thf)2] and [Pt{η2-HCtC(OH)Ph2}(PPh3)2] (2f)
(Scheme 2, ii). Surprisingly, after 2 min of reaction, the solution
was observed to contain the “trans”-type isomer 3f as the main
product (molar ratio 3f:4f 65:35), together with traces of the
(µ-hydroxy)(µ-vinyl) complex [cis,cis-(PPh3)2Pt{µ-1κCR:
η2-CHdCHC(OH)Ph2}(µ-OH)Pt(C6F5)2] (5f) (δP 22.8 (d), 8.1
(d)). Nevertheless, the low solubility of 4f allows its precipitation
from this solution mixture as a beige solid, although in low
yield (19%). For complexes 3f and 4f no adequate crystals for
X-ray diffraction studies have been obtained, but both of the
complexes have been fully characterized by the usual analytical
and spectroscopic means, with all the spectroscopic data being
similar to those previously described for complexes 3a-e and
4a-e (see Experimental Section and Supporting Information).
1.216(7)
1.213(9)
P(1)-Pt(1)-C(7)
C(13)-Pt(1)-Pt(2)
P(1)-Pt(1)-Pt(2)
C(7)-Pt(1)-Pt(2)
P(1)-Pt(1)-H(1)
C(7)-Pt(1)-H(1)
C(1)-Pt(2)-P(2)
C(1)-Pt(2)-C(13)
C(1)-Pt(2)-C(14)
C(1)-Pt(2)-Pt(1)
P(2)-Pt(2)-Pt(1)
C(1)-Pt(2)-H(1)
P(2)-Pt(2)-H(1)
91.21(13)
51.40(14)
156.24(3)
112.49(13)
168.1(18)
77.0(8)
89.78(14)
117.46(19)
86.41(19)
160.96(14)
108.71(3)
160.1(18)
70.5(18)
106.50(6)
50.00(15)
141.57(4)
111.93(4)
169(3)
P(1)-Pt(1)-P(2)
P(2)-Pt(1)-Pt(2)
84(3)
85.6(3)
P(2)-Pt(1)-H(1)
C(1)-Pt(2)-C(7)
119.8(2)
88.8(2)
163.80(18)
110.50(18)
167(3)
82(3)
166.5(5)
158.6(6)
C(7)-Pt(2)-Pt(1)
C(7)-Pt(2)-H(1)
Pt(1)-C(13)-C(14) 161.5(5)
C(13)-C(14)-C(15) 157.2(5)
coupling constant observed, 2JH-P1 (96.5-69.8 Hz), is assigned
to the phosphorus atom P1, which is seen practically trans to
the hydride ligand in the solid state. Thus, the other constant,
2JH-P2 (16.8-11.8 Hz), is attributed to the phosphorus atom
P2, located in a practically cis arrangement to the hydride
bridging ligand. For the “trans”-type derivatives, in which the
hydride atom bonds two “Pt(C6F5)(PPh3)” organometallic units,
1
two rather similar coupling JH-Pt are observed (1JH-Pt1 564-
1
550 Hz, JH-Pt2 515-510 Hz), which have been assigned on
the basis of the different trans influence of the C6F5 and PPh3
ligands (C6F5 > PPh3). The remarkable asymmetry of the “gem”
isomers (4) is clearly reflected in the greater difference of the
1
1JH-Pt coupling constants (1JH-Pt1 638-555 Hz, JH-Pt2 465-
448 Hz).
Nevertheless, the most significant spectroscopic difference
between both types of isomers is found in the 31P NMR spectra
(Figure 4). Both of them show the signals that are due to the
presence of two nonequivalent PPh3 ligands. However, while
the “gem”-type complexes display two sharp doublet resonances
(2JP-P ≈ 22 Hz) with the corresponding platinum satellites, the
“trans”-type derivatives show only two singlets with the
corresponding platinum satellites, and because of this, the three-
bond phosphorus-phosphorus coupling, 3JP-P, is not resolved.
In the “trans”-type complexes 3 (Figure 4a), the most deshielded
singlet resonance (δ 27.4-29.2), which exhibits larger short-
range (1JPt1-P1 ) 3853-3826 Hz) and long-range (2JPt2-P1
≈
Finally, the (µ-hydroxy)(µ-vinyl) complex 5f can be obtained
in good yield (77%) as a yellow solid by addition of two drops
of deoxygenated water to an anhydrous solution of [Pt{η2-
HCtC(OH)Ph2}(PPh3)2] (2f) in CH2Cl2, followed by the
immediate addition of a stoichiometric amount of [cis-Pt(C6F5)2-
(thf)2] (Scheme 2, iii). Under these conditions, the reac-
tion mixture is shown to contain (31P{1H} NMR) a mixture
of the (µ-hydroxy)(µ-vinyl) complex 5f and the “trans”-type
(µ-hydride)(µ-acetylide) derivative 3f (molar ratio 80:20, re-
spectively), together with traces of the “gem”-type (µ-hydride)-
(µ-acetylide) isomer 4f.
100 Hz) coupling constants, is assigned to the nucleus P1, in
accordance with the observed open angle P(1)-Pt(1)-Pt(2)
(141.57(4)-157.92(6)°). The low-frequency signal centered at
ca. 10 ppm, which exhibits only one set of platinum satellites
(1JPt2-P2 ) 3593-3401 Hz) except for 3a (R ) (4-CH3)C6H4,
2JPt1-P2 ) 30 Hz), is, therefore, assigned to the phosphorus atom
(P2) of the phosphine cis to the hydride ligand. The assignation
has been unambiguously confirmed by recording the spectrum
of complex 3a while decoupling only the phosphine protons
(Figure 4b). In this case, only the downfield signal (δP1 29.0)

Rearrangement Promoted by the SolVate [cis-Pt(C6F5)2(thf)2]
Organometallics, Vol. 26, No. 5, 2007 1165
1
Figure 3. High-field region of the H NMR spectra of 3a (a) and 4a (b).
In view of these results, we have tried to obtain some other
counterpart dinuclear hydroxy-vinyl derivatives, starting from
two representative Pt(0) mononuclear complexes, [Pt(η2-
HCtCR)(PPh3)2] 2a (R ) (4-CH3)C6H4) and 2d (R ) C(OH)-
Me2), although in spite of the presence of water in both reactions
only the “gem”-type complexes [cis,cis-(PPh3)2Pt-
(µ-H)(µ-1κCR:η2-CtCR)Pt(C6F5)2] (R ) (4-CH3)C6H4, 4a;
C(OH)Me2, 4d) have been detected and isolated.
Complex 5f has been characterized by an X-ray diffraction
structural analysis (Figure 5, Table 3), confirming the presence
of a mixed (µ-hydroxy)(µ-vinyl) bridging system. As far as we
know, this structural feature has no precedent in the literature,
the most similar examples being a (µ-hydroxy)(µ-alkyne)
bridging system in a pentanuclear ruthenium cluster41 and a (µ-
hydroxy)(µ-allenylidene) trinuclear osmium cluster.42 Notwith-
standing, a good number of vinyl groups acting as bridging
ligands between two transition metals have been reported,43-51
although the examples containing platinum are really scarce,52-58
in particular, those referring to homopolynuclear deriva-
tives.15,34,59 It should be noted that recently a (µ-hydride)-
(µ-vinyl) dinuclear intermediate species has been proposed in
the formation of the (µ-alkylidene) complex [Pt2(dppm)2(µ-H)-
(µ-CHCH2Ph)](BF4).28
In 5f both platinum centers present a practically square-planar
environment, the dihedral angle between the two platinum
coordination planes being 56.80(9)°. The loss of the planarity
of 5f, which contrasts to the planar cores shown by the (µ-
hydride)(µ-acetylide) complexes 3 and 4, is reflected in the
dihedral angle between the vectors defined by Pt(1)-Pt(2) and
(49) Dennet, J. N. L.; Knox, S. A. R.; Anderson, K. M.; Charmant, J. P.
H.; Orpen, A. G. Dalton Trans. 2005, 63.
(50) Hua, R.; Akita, M.; Moro-Oka, Y. Inorg. Chim. Acta 1996, 250,
177.
(51) Albano, V. G.; Busetto, L.; Marchetti, F.; Monari, M.; Zacchini,
S.; Zanotti, V. Organometallics 2003, 22, 1326.
(52) Cao, D. H.; Stang, P. J.; Arif, A. M. Organometallics 1995, 14,
2733.
(53) Tsutsuminai, S.; Komine, N.; Hirano, M.; Komiya, S. Organome-
tallics 2004, 23, 44.
(54) Fontaine, X. L. R.; Jacobsen, G. B.; Shaw, B. L.; Thornton-Pett,
M. J. Chem. Soc., Dalton Trans. 1988, 741.
(55) Awang, M. R.; Jeffery, J. C.; Stone, F. G. A. J. Chem. Soc., Dalton
Trans. 1986, 165.
(41) Lau, C. S.-W.; Wong, W.-T. J. Chem. Soc., Dalton Trans. 1999,
607.
(42) Aime, S.; Deeming, A. J.; Hursthouse, M. B. J. Chem. Soc., Dalton
Trans. 1982, 1625.
(43) Au, Y.-K.; Wong, K.-T. J. Chem. Soc., Dalton Trans. 1996, 899.
(44) Gao, Y.; Jennings, M. C.; Puddephatt, R. J. Dalton Trans. 2003,
261.
(45) Dennet, J. N. L.; Jacke, J.; Nilsson, G.; Rosborough, A.; Ferguson,
M. J.; Wang, M.; McDonald, R.; Takats, J. Organometallics 2004, 23, 4478.
(46) Liu, Y.-C.; Yeh, W.-Y.; Lee, G.-H.; Peng, S.-M. J. Organomet.
Chem. 2004, 689, 1944.
(47) Lau, J. P.-K.; Wong, K.-T. Inorg. Chem. Commun. 2003, 6, 174.
(48) Jin, S.-Y.; Wu, C.-Y.; Lee, C.-S.; Datta, A.; Hwang, W.-S. J.
Organomet. Chem. 2004, 689, 3173.
(56) Lukehart, C. M.; True, W. R. Organometallics 1988, 7, 2387.
(57) Willis, R. R.; Calligaris, M.; Faleschini, P.; Gallucci, J. C.; Wojcicki,
A. J. Organomet. Chem. 2000, 593-594, 465.
(58) Ashworth, T. V.; Berry, M.; Howard, J. A. K.; Laguna, M.; Stone,
F. G. A. J. Chem. Soc., Chem. Commun. 1979, 43.
(59) Boag, N. M.; Goodfellow, R. J.; Green, M.; Hessner, B.; Howard,
J. A. K.; Stone, F. G. A. J. Chem. Soc., Dalton Trans. 1983, 2585.

1166 Organometallics, Vol. 26, No. 5, 2007
Berenguer et al.
Figure 4. 31P{1H} NMR spectra of 3a (a), 3a with selective decoupling of the aromatic protons only (b), and 4a (c).
C(13)-C(14) (57.11(24)°). The hydroxyl ligand connects both
platinum atoms symmetrically (Pt(1)-O(1) 2.115(2) Å,
Pt(2)-O(1) 2.107(3) Å), while the vinyl groups are σ-bonded
to the atom Pt(1) (Pt(1)-C(13) 2.041(3) Å) and π-bonded in a
slightly asymmetrical way to Pt(2) (Pt(2)-C(13), C(14) 2.216-
(3), 2.257(3) Å). These features, as well as the C(13)dC(14)
distance (1.373(5) Å), are similar to those observed for other
µ-vinyl platinum derivatives.15,34,52 In accordance with the
formation of a 32-electron complex, the distance Pt‚‚‚Pt of
3.06274(17) Å is larger than that observed for 3 and 4 (∼2.83
Å), indicating the absence of a Pt-Pt bond in this complex (in
(9) Å), in agreement with the greater trans influence of the
σ-vinyl group in relation to the hydroxy ligand. This structural
feature has also been used in the assignation of the two doublets
observed in the 31P{1H} NMR spectrum of 5f (δP1 8.1, 1JPt1-P1
) 4272 Hz; δP2 22.8, JPt1-P2 ) 1619 Hz; JP-P ) 14.5 Hz).
Its 19F NMR spectrum confirms the presence of two nonequiva-
lent pentafluorophenyl rings with different energetic barriers
for rotation around the corresponding Pt-C(ipso) bonds, as is
observed by the different pattern of the ortho-fluorine resonances
of both rings (see Experimental Section).
1
2
The 195Pt NMR spectrum has also been recorded. It shows
only the signal assigned to Pt1 as a doublet of doublets at -4240
2
addition, no JPt-P coupling constants are observed in the
31P{1H} NMR spectrum). Nevertheless, this distance is shorter
than the sum of van der Waals radii (3.50 Å),60 and the presence
of any weak interaction between the metal centers cannot be
excluded.61-64 Finally, it should be noted that both Pt-P
distances are quite different (Pt(1)-P(1), P(2) 2.2125(8), 2.3457-
(61) Yamazaki, S.; Taira, Z.; Yonemura, M.; Deeming, A. J. Organo-
metallics 2005, 24, 20.
(62) Herebian, D.; Bothe, E.; Neese, F.; Weyhevmu¨ller, T.; Wieghardt,
K. J. Am. Chem. Soc. 2003, 125, 9116.
(63) Itazaki, M.; Nishihara, Y.; Osakada, K. Organometallics 2004, 23,
1610.
(60) Winter, M. WebElementsTM, the periodic table on the www, http://
www.webelements.com; The University of Shefield: U.K.
(64) Albinati, A.; Leoni, P.; Marchetti, L.; Rizzato, S. Angew. Chem.,
Int. Ed. 2003, 42, 5990.

Rearrangement Promoted by the SolVate [cis-Pt(C6F5)2(thf)2]
Organometallics, Vol. 26, No. 5, 2007 1167
Scheme 2
1
ppm (1JPt1-P1 ≈ 4300 Hz, JPt1-P2 ≈ 1900 Hz). We have not
been able to observe the signal corresponding to Pt2, probably
due to its coupling with the four ortho-F of the C6F5 groups.
pling of Pt1 in the proton NMR spectrum, which shows no
modification in the signal at 5.85 ppm, and also previous
assignments in vinyl bridging ligands.15,34,45,50,52,55,56,65,66 The
CR and Câ vinylic signals appear at 117.6 and 105.0 ppm, as
has been confirmed by a C,H correlation experiment (see Figure
S2b).
1
Particularly significant is the H NMR spectrum of complex
5f, which shows the signals due to the vinylic protons at δ 6.46
(HR, dd, 3JP-H ) 14.0 Hz, JH-H ) 7.4 Hz, -CHRdCHâC(OH)-
Ph2) and 5.85 (Hâ, m) (see Figure S2a in the Supporting
Information). Hâ is also coupled to the platinum nucleus Pt2,
showing the corresponding platinum satellites (2JHâ-Pt2 ≈ 60
Hz). This assignation has been confirmed by selective decou-
With the aim of establishing the mechanism concerned with
the formation of 5f, we have carried out a series of experiments.
First, it was confirmed by 1H and 31P{1H} NMR spectroscopy
in CDCl3 that the alkyne precursor [Pt{η2-HCtC(OH)Ph2}-
(PPh3)2] (2f) does not react with H2O (2 drops for 2 weeks). It
was observed that water attacks only when [cis-Pt(C6F5)2(THF)2]
is present in the reaction mixture and has started to react
with the alkyne Pt(0) precursor. The reaction between [Pt{η2-
HCtC(OH)Ph2}(PPh3)2] (2f) and [cis-Pt(C6F5)2(THF)2] was
also monitored (1H, 19F, and 31P{1H} NMR), starting from 223
K. (This reaction was not carried out in anhydrous conditions,
but without addition of H2O. See Experimental Section and
Figure S3 in the Supporting Information for details.) On raising
the temperature, the resonances due to the starting materials
decreased in their relative intensity, while signals corresponding
to a unique, new compound, which has been identified spec-
troscopically as the mixed-valence intermediate [cis,cis-(PPh3)2-
Pt{µ-η2:η2-HCtC(OH)Ph2}Pt(C6F5)2(thf)] (6f), appeared and
grew in intensity until 263 K. Above this temperature, the sig-
nals due to 6f started to decrease in intensity, while the reso-
nances assigned to the (µ-hydroxy)(µ-vinyl) complex [cis,cis-
(PPh3)2Pt{µ-1κCR:η2-CHdCHC(OH)Ph2}(µ-OH)Pt(C6F5)2] (5f)
appeared. The signals corresponding to the (µ-hydride)-
(µ-acetylide) isomers [trans-(PPh3)(C6F5)Pt(µ-H){µ-1κCR:
η2-CtCC(OH)Ph2}Pt(C6F5)(PPh3)] (3f) and [cis,cis-(PPh3)2Pt-
Figure 5. ORTEP view of [cis,cis-(PPh3)2Pt{µ-1κCR:η2-CHd
CHC(OH)Ph2}(µ-OH)Pt(C6F5)2] (5f). Ellipsoids are drawn at the
50% probability level. Aromatic hydrogen atoms have been omitted
for clarity.
(65) Bamber, M.; Conole, G. C.; Deeth, R. J.; From, S. F. T.; Green, M.
J. Chem. Soc., Dalton Trans. 1994, 3569.
(66) Stang, P. J.; Huang, J. C.; Arif, A. M. Organometallics 1992, 11,
845.

1168 Organometallics, Vol. 26, No. 5, 2007
Berenguer et al.
Table 3. Selected Bond Lengths (Å) and Angles (deg) for [cis,cis-(PPh3)2Pt(µ-OH){µ-1KCr:η2-CHdCHC(OH)Ph2}Pt(C6F5)2] (5f)
Pt(1)-C(13)
Pt(1)-O(1)
Pt(2)-C(7)
C(13)-C(14)
Pt(1)-Pt(2)
2.041(3)
2.115(2)
2.021(3)
1.373(5)
3.06274(17)
Pt(1)-P(1)
2.2125(8)
2.107(3)
2.216(3)
1.523(5)
0.92(3)
Pt(1)-P(2)
Pt(2)-C(1)
Pt(2)-C(14)
O(1)-H(1)
C(14)-H(14)
2.3457(9)
1.998(4)
2.257(3)
0.63(4)
Pt(2)-O(1)
Pt(2)-C(13)
C(14)-C(15)
C(13)-H(13)
0.92(4)
C(13)-Pt(1)-P(1)
91.53(10)
P(1)-Pt(1)-P(2)
O(1)-Pt(1)-P(2)
P(2)-Pt(1)-Pt(2)
C(7)-Pt(2)-O(1)
C(1)-Pt(2)-Pt(1)
C(7)-Pt(2)-Pt(1)
C(13)-C(14)-C(15)
97.13(3)
C(13)-Pt(1)-O(1)
P(1)-Pt(1)-Pt(2)
80.01(12)
129.08(2)
88.35(14)
76.83
99.01
120.8(3)
91.32(8)
126.26(2)
95.77(13)
131.68(11)
120.89(10)
124.2(3)
C(1)-Pt(2)-C(7)
O(1)-Pt(2)-C(13,14)
C(1)-Pt(2)-C(13,14)
Pt(1)-C(13)-C(14)
Scheme 3
2
(µ-H){µ-1κCR:η2-CtCC(OH)Ph2}Pt(C6F5)2] (4f) were observed
for the first time at 283 K, showing that, although the C-H
activation process that is involved in their formation occurs in
smooth conditions, it does not work at low temperature. Finally,
at 293 K, the reaction mixture consists of a small amount (less
than 10%) of 4f, together with an approximately equimolecular
mixture of 3f and 5f, revealing that the formation of 5f is very
sensitive to the presence of small amounts of water, since when
the reaction is performed in anhydrous conditions (as previously
described), only traces of 5f can be detected.
resonance, also with platinum satellites (δH 5.97, JH-Pt ≈ 47
3
3
Hz, JH-Ptrans ≈ 24 Hz, JH-Pcis ≈ 7 Hz, see Figure S3b), that
is very similar to that observed for the acetylenic proton (t
C-H) in the precursor 2f (δH 6.46, 2JH-Pt ) 57.2 Hz, 3JH-Ptrans
) 22.7 Hz, 3JH-Pcis ) 9.6 Hz). Bearing in mind the intermediate
species 6f, the mechanism illustrated in Scheme 3 could be
tentatively proposed. It seems clear that in the absence of water,
the coordination of the electron-acceptor synthon “cis-Pt(C6F5)2-
(thf)” (Scheme 3, i) favors the activation of the acetylenic C-H
bond and its subsequent oxidative addition on the Pt(0) center
to give the “gem”-type derivative [cis,cis-(PPh3)2Pt(µ-H){µ-
1κCR:η2-CtCC(OH)Ph2}Pt(C6F5)2] (4f) (Scheme 3, ii) and the
“trans”-type isomer [trans-(PPh3)(C6F5)Pt(µ-H){µ-1κCR:η2-Ct
CC(OH)Ph2}Pt(C6F5)(PPh3)] (3f). Nevertheless, the coordination
of the synthon “cis-Pt(C6F5)2(thf)” should also decrease the
electron density over the fragment “cis-Pt(PPh3)2”, which could
allow the nucleophillic attack of the water on the Pt(0) center
(Scheme 3, iv), leading to the formation of the (µ-hydroxy)(µ-
vinyl) complex [cis,cis-(PPh3)2Pt{µ-1κCR:η2-CHdCHC(OH)-
Ph2}(µ-OH)Pt(C6F5)2] (5f) (Scheme 3, steps v and vi). Not-
withstanding, it must be noted that the substituent of the alkyne
ligand (R ) C(OH)Ph2) must also play a certain role in the
process, since we have not been able to obtain other related
The intermediate mixed-valence species 6f has been detected
1
by H, 19F, and 31P{1H} NMR spectroscopy, and its spectro-
scopic data are given at 263 K (see Experimental Section). Thus,
the 19F NMR spectrum shows the signals corresponding to the
presence of two nonequivalent C6F5 groups, while two doublet
resonances with platinum satellites are observed in the phos-
phorus NMR spectrum (see Figure S3a), their corresponding
coupling constants being similar to those observed for the
Pt(0) precursor [Pt{η2-HCtC(OH)Ph2}(PPh3)2] (2f) (δP 32.2,
1JPt-P ) 3665 Hz; δP 27.9, 1JPt-P ) 3571.8 Hz; 2JP-P ) 14 Hz
1
1
6f vs δP 26.9, JPt-P ) 3553 Hz; δP 24.9, JPt-P ) 3503 Hz;
2JP-P ) 27.5 Hz 2f). In the 1H NMR spectrum, the most
significant feature is the appearance of a doublet of doublets

Rearrangement Promoted by the SolVate [cis-Pt(C6F5)2(thf)2]
Organometallics, Vol. 26, No. 5, 2007 1169
Scheme 4
(µ-hydroxy)(µ-vinyl) species starting from 2a and 2d, as
previously mentioned. In fact, it should be also noted that the
formation of 3f under these mild conditions in this system is
rather surprising, and it is unclear at this moment whether 3f
comes from isomerization of the final 4f (Scheme 3, iii) or,
more likely, by isomerization of a previous 32e- intermediate
species such as A (Scheme 3, vii).
polymetallic mixed-bridged (µ-hydride)(µ-acetylide) complexes.
Thus, a good number of new functionalized isomeric derivatives
[trans-(PPh3)(C6F5)Pt(µ-H)(µ-1κCR:η2-CtCR)Pt(C6F5)-
(PPh3)] (3, “trans”-type) and [cis,cis-(PPh3)2Pt(µ-H)(µ-1κCR:
η2-CtCr)Pt(C6F5)2] (4, “gem”-type) (R ) (4-CH3)-C6H4, a; (4-
CN)C6H4, b; CMedCH2, c; C(OH)Me2, d; C(OH)EtMe, e;
C(OH)Ph2, f) have been prepared by reaction of the disolvated
[cis-Pt(C6F5)2(thf)2] with the corresponding Pt(II) [trans-PtH-
(CtCR)(PPh3)2] (1) or Pt(0) [Pt(η2-HCtCR)(PPh3)2] (2)
isomers. The most thermodynamically stable of the two di-
nuclear isomers seem to be the “trans”-type derivatives 3, since
continuous heating of solutions of the “gem”-type complexes 4
leads to their isomerization to 3, although with abundant
decomposition. In spite of being such different processes, the
first involves a deep reorganization of the ligands around the
metal centers, while the second occurs through a C-H activation
of the acetylenic proton, the formation of both of the (µ-
hydride)(µ-acetylide) compounds occurs in mild conditions, and
they seem to be rather general. Notwithstanding, the course of
the reaction with the alkyne Pt(0) precursors can be influ-
enced by the nature of the same radicals at the alkynylic rest
(tC-R). Thus, the use of [Pt{η2-HCtC(OH)Ph2}(PPh3)2] (2f)
in the presence of water leads to the formation of the unexpected
(µ-hydroxy)(µ-vinyl) complex [cis,cis-(PPh3)2Pt{µ-1κCR:
η2-CHdCHC(OH)Ph2}(µ-OH)Pt(C6F5)2] (5f), while the re-
action with [Pt(η2-HCtC5H4N-4)(PPh3)2] (2g) produces the
stable trinuclear mixed-valence adduct [{(PPh3)2Pt(µ-η2:
2κN-HCtCC5H4N-4)}2{cis-Pt(C6F5)2}] (7g).
Reaction of [cis-Pt(C6F5)2(thf)2] with [Pt(η2-HCtCC5H4N-
4)(PPh3)2] (2g). As commented on in the Introduction, some
time ago we reported that the treatment of the pyridylacetylide
complex [trans-PtH(CtCC5H4N-2)(PPh3)2] with [cis-Pt(C6F5)2-
(thf)2] affords the initial adduct [trans,cis-(PPh3)2HPt(µ-1κCR:
η2R,â:2κN-CtCC5H4N-2)Pt(C6F5)2], which finally rearranges to
form an unexpected tetranuclear platinum cluster containing a
vinyl group capping three platinum atoms.34 This reaction, which
reveals the influence of the donor nitrogen atom at the pyridyl-
acetylide ligand in the course of this type of reactions, has
encouraged us to explore the reactivity of the Pt(II) isomer
[trans-PtH(CtCC5H4N-4)(PPh3)2], with the nitrogen atom in
the para position. Unfortunately, we have not succeeded in
obtaining this complex, although the new Pt(0) isomer [Pt(η2-
HCtCC5H4N-4)(PPh3)2] (2g) is easily synthesized.
A completely different reaction route has been found in the
reaction of [cis-Pt(C6F5)2(thf)2] with [Pt(η2-HCtCC5H4N-4)-
(PPh3)2], 2g. Thus, the equimolecular reaction leads only to
complex mixtures, from which we have not been able to isolate
a pure complex. Nevertheless, when the reaction is carried out
using 2 equiv of the Pt(0) substrate 2g (Scheme 4), a stable
yellow solid, identified as the trinuclear mixed-valence adduct
[{(PPh3)2Pt(µ-η2:2κN-HCtCC5H4N-4)}2{cis-Pt(C6F5)2}] (7g),
is obtained in good yield (76%). This complex is also stable in
solution for a long time if it is stored cold.
Experimental Section
All reactions were carried out under an atmosphere of dry argon,
using standard Schlenk techniques. Solvents were dried by standard
procedures and distilled under dry Ar before use. 1-Cyano-4-
ethynylbenzene67 was prepared by literature methods, while the rest
of the alkynes and NEt2H were used as received. NMR spectra
were recorded at 293 K on a Bruker ARX 300 or ARX 400
spectrometer. Chemical shifts are reported in ppm relative to
external standards (SiMe4, CFCl3, 85% H3PO4, or Na2PtCl6 in D2O
for 195Pt), and all coupling constants are given in Hz. The NMR
spectral assignments of the alkynyl ligands containing substituted
aryl and pyridyl groups follow the numbering scheme shown in
Figure 6. IR spectra were obtained on Perkin-Elmer 883 or Perkin-
Elmer FT-IR Spectrum 1000 spectrometers, using Nujol mulls
between polyethylene sheets. Elemental analyses were carried out
with a Perkin-Elmer 2400 CHNS/O or Carlo Erba EA1110
CHNS-O microanalyzer. Mass spectra were recorded on a HP-
5989B (ES) or a VG Autospec double-focusing (FAB) mass
spectrometer. [trans-PtHCl(PPh3)2],68 [trans-PtH(CtCR)(PPh3)2]
(R ) CMedCH2, 1c; C(OH)Me2, 1d; C(OH)EtMe, 1e),35 [η2-Pt-
(HCtCCMe2dCH2)(PPh3)2] (2c),69 [Pt{η2-HCtCC(OH)Ph2}-
7g has been fully characterized by the usual analytical and
spectroscopic means, and all the spectroscopic data are in
agreement with the proposed structure (see Experimental
Section). In accordance with the presence of the Pt(0) fragments
“cis-Pt(PPh3)2” bonded in a η2-fashion to the triple bond of the
alkynes, the IR spectrum shows a medium-intensity absorption
at 1685 cm-1 and in the proton NMR spectrum the signal
due to the acetylenic proton is observed as a doublet of doublets
3
at 7.51 ppm (3JPtrans-H ) 21.1 Hz, JPcis-H ) 12.0 Hz). The
31P{1H} and 13C{1H} spectra display resonances corresponding
to the presence of two types of nonequivalent PPh3 ligands,
these signals being very similar to those observed for the
mononuclear Pt(0) precursor 2f (e.g., δP 27.3, 1JPt-P ) 3477.8
1
2
Hz; δP 25.8, JPt-P ) 3587.8 Hz; JP-P ) 26.8 Hz 7g vs δP
1
1
2
28.8, JPt-P ) 3499.6 Hz; δP 26.0, JPt-P ) 3527.5 Hz; JP-P
) 29.8 Hz 2f). Finally, the symmetry of the molecule is well
established by the presence of only three signals (δF -120.48,
3JPt-F ≈ 470, 4ortho-F; δF -163.66, 2para-F; δF -165.52,
4meta-F) in the 19F NMR spectrum, which indicates that both
of the C6F5 rings are chemically equivalent.
Conclusions
In this paper we explore the influence of the nature of the
radicals in the alkynylic rest (tC-R) in two easy entries to
Figure 6.

1170 Organometallics, Vol. 26, No. 5, 2007
Berenguer et al.
(PPh3)2] (2f) and its mixture with [trans-PtH{CtCC(OH)Ph2}-
(PPh3)2] (1f),36 and [cis-Pt(C6F5)2(thf)2]70 were prepared by published
methods. The syntheses of the rest of the complexes 1 and 2, as
well as the derivatives 3b-e and 4b-e, are included in the
Supporting Information.
-115.00 (d, 3JPt-F ) 362.6, 2ortho-F); -115.98 (dd, 3JPt-F ) 286.5,
2ortho-F); -162.60 (m, 1para-F); -163.45 (m, 2meta-F); -164.41
(t, 1para-F); -165.01 (m, 2meta-F). 31P NMR (CDCl3, δ): 29.4
(s, 1JPt1-P1 ) 3811.2, 2JPt2-P1 ) 99.6, P1 trans to hydride); 10.1 (s,
1JPt2-P2 ) 3441.8, P2 trans to CtC).
Synthesis of [trans-(PPh3)(C6F5)Pt(µ-H){µ-1κCR:η2-CtC(4-
CH3)C6H4}Pt(C6F5)(PPh3)] (3a). [cis-Pt(C6F5)2(thf)2] (0.15 g, 0.22
mmol) was added to a CH2Cl2 solution (20 mL) of [trans-PtH-
{CtC(4-CH3)C6H4}(PPh3)2]‚CHCl3 (1a) (0.20 g, 0.21 mmol), and
the mixture was stirred at room temperature for 30 min. The
resulting pale orange solution was evaporated to dryness, and
the residue was treated with hexane, yielding 3a as a white
solid. Yield: 0.25 g (87%). Anal. Calcd for C57F10H38P2Pt2: C,
50.15; H, 2.81. Found: C, 49.72; H, 3.04. MS ES(+): m/z 1474
[M + Ag + H]+ 100% (sample ionizated with Ag+). IR (cm-1):
Synthesis of [cis,cis-(PPh3)2Pt(µ-H){µ-1κCR:η2-CtC(4-CH3)-
C6H4}Pt(C6F5)2] (4a). [cis-Pt(C6F5)2(thf)2] (0.10 g, (0.15 mmol)
was added to a CH2Cl2 solution (10 mL) of [Pt{η2-HCtC(4-CH3)-
C6H4}(PPh3)2] (2a) (0.13 g, 0.16 mmol), and the mixture was stirred
at room temperature for 5 min. The resulting orange solution was
evaporated to dryness, and the residue was treated with cold
EtOH, yielding 4a as a beige solid. Yield: 0.10 g (65%). Anal.
Calcd for C57F10H38P2Pt2: C, 50.15; H, 2.81. Found: C, 50.47; H,
2.50. MS ES(-): m/z 736 [Pt(CCTol)(C6F5)(PPh3) - 3]- 20%;
563 [Pt(PPh2)2 - 2]- 100%; 530 [Pt(C6F5)2 + 1] 15%. IR (cm-1):
1
1
ν(CtC) 2018 (w); ν(C6F5)x-sensitive 820 (m), 794 (m). H NMR
ν(CtC) 2019 (w); ν(C6F5)x-sensitive 803 (m), 794 (m). H NMR
(CDCl3, δ): 7.61 (m, 6H), 7.33 (m, 24H) (Ph, PPh3); 6.93, 6.82
(AB, JH-H ) 7.4, 4H, C6H4, Tol); 2.20 (s, 3H, CH3, Tol); -7.42
(dd, 2JP1-H ) 74.6, 2JP2-H ) 13.9, 1JPt1-H ) 564.0, 1JPt2-H ) 510.0,
Pt-µH-Pt). 13C NMR (CDCl3, δ): 148-134.5 (C6F5); 138.6 (s,
(CDCl3, δ): 7.39, 7.27, 7.15 (m, 30H, Ph, PPh3); 6.73 (d, JH-H
)
7.3, 2H), 6.55 (d, JH-H ) 7.3, 2H) (C6H4, Tol); 2.19 (s, 3H, CH3,
Tol); -7.21 (dd, 2JP1-H ) 96.5, 2JP2-H ) 13, 1JPt1-H ) 638, 1JPt2-H
3
) 448, Pt-µH-Pt). 19F NMR (CDCl3, δ): -116.86 (dm, JPt-F
C4); 134.3 (d, 2JC-P ) 12.0, ortho-C, Ph, PPh3); 133.8 (d, 2JC-P
)
) 406.2, 2ortho-F); -118.78 (d, 3JPt-F ) 458.4, 2ortho-F); -164.48
(t, 1para-F); -164.52 (t, 1para-F); -165.32 (m, 2meta-F); -165.65
11.1, ortho-C, Ph, PPh3); 131.0 (d, 4JC-P ) 2.6, para-C, Ph, PPh3);
130.8 (d, 4JC-P ) 2.5, para-C, Ph, PPh3); 131.4, 131.2, 130.4, 130.2,
1
(m, 2meta-F). 31P NMR (CDCl3, δ): 13.2 (d, JPt1-P1 ) 3364.9,
3
129.3 (C2, C3, 2ipso-C of Ph); 128.1 (d, JC-P ) 7.3, meta-C, Ph,
2JPt2-P1 ) 55.8, 2JP-P ) 22.4, P1 trans to hydride); 11.5 (d, 1JPt1-P2
) 2701.0, 2JPt2-P2 ) 48.5, 2JP-P ) 22.4, P2 trans to σ-CtC). The
complex is not soluble enough for 13C NMR.
PPh3); 128.0 (d, 3JC-P ) 7.3, meta-C, Ph, PPh3); 121.7 (d, 4JC-P
)
3.5, 3JPt-C ) 21.4, C1); 110.4 (d, 2JC-P ) 20.8, CR); 21.3 (s, CH3).
3
19F NMR (CDCl3, δ): -116.33 (dd, JPt-F ) 288.0, 2ortho-F);
Synthesis of [cis,cis-(PPh3)2Pt(µ-H){µ-1κCR:η2-CtCC(OH)-
Ph2}Pt(C6F5)2] (4f). [cis-Pt(C6F5)2(thf)2] (0.14 g, 0.21 mmol) was
added to a solution of 0.20 g (0.21 mmol) of [Pt{η2-HCtC(OH)-
Ph2}(PPh3)2] (2f) in CH2Cl2 (∼20 mL), and the reaction was studied
by 31P{1H} NMR. After 2 min, the orange solution obtained
consisted of a mixture of the isomers [trans-(PPh3)(C6F5)Pt(µ-H)-
{µ-1κCR:η2-CtCC(OH)Ph2}Pt(C6F5)(PPh3)] (3f) and [cis,cis-
(PPh3)2Pt(µ-H){µ-1κCR:η2-CtCC(OH)Ph2}Pt(C6F5)2] (4f) (molar
ratio ∼65:35, respectively) and traces of the (µ-hydroxy)(µ-vinyl)
complex [cis,cis-(PPh3)2Pt{µ-1κCR:η2-CHdCHC(OH)Ph2}(µ-OH)-
Pt(C6F5)2] (5f). The solution was evaporated to small volume (∼4
mL), and 5 mL of EtOH was added. On cooling the mixture, 4f
was obtained as a beige solid. Yield: 0.06 g (19%). Anal. Calcd
for C63F10H42OP2Pt2: C, 51.93; H, 2.91. Found: C, 51.41; H, 3.60.
MS ES(+): m/z 1052 [M - (C6F5) - (PPh3) + Na + 2H]+ 16%;
833 [Pt(CCCPh2OH)(C6F5)(PPh3) + 2H]+ 14%; 791 [M - (C6F5)
- 2(PPh3) + Na + 3H]+ 100%; 721 [Pt(PPh3)2 + 2H]+ 20%; 628
[Pt(C6F5)(PPh3) + 4H]+ 18% (sample ionized with Na+). IR (cm-1):
ν(OH) 3592 (w); ν(CtC) 1987 (w); ν(C6F5)x-sensitive 802 (s), 793
(s). 1H NMR (CDCl3, δ): 7.26, 7.14, 6.87, 6.80 (m, 40H, Ph, PPh3,
and C(OH)Ph2); 3.13 (s, 1H, OH); -7.74 (dd, 2JP1-H ) 91.1, 2JP2-H
) 11.7, 1JPt1-H ≈ 640, 1JPt2-H ≈ 460, Pt-µH-Pt). 19F NMR (CDCl3,
3
-118.62 (d, JPt-F ) 346.1, 2ortho-F); -163.87 (tt, 1para-F);
-164.39 (m, 2meta-F); -164.68 (t, 1para-F); -165.30 (m, 2meta-
1
2
F). 31P NMR (CDCl3, δ): 29.0 (s, JPt1-P1 ) 3845.7, JPt2-P1
)
≈
1
2
97.4, P1 trans to hydride); 11.5 (s, JPt2-P2 ) 3593.0, JPt1-P2
30, P2 trans to CtC).
Synthesis of [trans-(PPh3)(C6F5)Pt(µ-H){µ-1κCR:η2-CtCC-
(OH)Ph2}Pt(C6F5)(PPh3)] (3f). To a solution of 0.14 g (0.15 mmol)
of a mixture of [trans-PtH{CtCC(OH)Ph2}(PPh3)2] (1f) and [Pt-
{η2-HCtC(OH)Ph2}(PPh3)2] (2f) (molar ratio ∼80:20, respectively)
in CH2Cl2 (∼15 mL) was added 0.10 g (0.15 mmol) of [cis-Pt-
(C6F5)2(thf)2], and the reaction was studied by 31P{1H} NMR. After
2 min the orange solution obtained consisted of a mixture of
complex 3f and its isomer [cis,cis-(PPh3)2Pt(µ-H){µ-1κCR:η2-Ct
CC(OH)Ph2}Pt(C6F5)2] (4f), in a molar ratio ∼85:15, respectively.
The solution was evaporated to dryness and the solid residue treated
with MeOH to give an orange solid. Its recrystallization from
CHCl3/hexane afforded pure 3f as a white solid. Yield: 0.09 g
(42%). Anal. Calcd for C63F10H42OP2Pt2: C, 51.93; H, 2.91.
Found: C, 51.50; H, 2.36. MS ES(+): m/z 1313 [M - (C6F5) +
Na + H]+ 1%; 1052 [M - (C6F5) - (PPh3) + Na + 2H]+ 28%;
831 [Pt(CCCPh2OH)(C6F5)(PPh3)]+ 5%; 791 [M - (C6F5) -
2(PPh3) + Na + 3H]+ 100%; 628 [Pt(C6F5)(PPh3) + 4H]+ 37%;
(sample ionized with Na+). IR (cm-1): ν(OH) 3598 (m); ν(CtC)
3
3
δ): -115.55 (m, JPt-F ≈ 486, 2ortho-F); -118.57 (dm JPt-F
≈
414, 2ortho-F); -163.34 (t, 1para-F); -163.59 (t, 1para-F);
-164.28 (m, 2meta-F); -164.84 (m, 2meta-F). 31P NMR (CDCl3,
1
2019 (w); ν(C6F5)x-sensitive 794 (m). H NMR (CDCl3, δ): 7.43,
7.34, 7.12, 6.91, 6.86 (m, 40H, Ph, PPh3, and C(OH)Ph2); 2.71 (s,
1H, OH); -7.57 (dd, 2JP1-H ) 72.4, 2JP2-H ) 13.6, 1JPt1-H ≈ 550,
1JPt2-H ≈ 505, Pt-µH-Pt). 13C NMR (CDCl3, δ): 150-135 (C6F5);
145.5 (tentatively attributed to ipso-C, Ph, C(OH)Ph2); 134.3 (d,
2JC-P ) 12.2, ortho-C, Ph, PPh3); 133.8 (d, 2JC-P ) 11.5, ortho-C,
Ph, PPh3); 131.1 (s), 130.9 (s) (para-C, Ph, PPh3; the signals due
to ipso-C of both PPh3 overlap with the para-C); 128.1, 128.0 (s,
meta-C, Ph, PPh3); 127.5 (s, ortho-C, Ph, C(OH)Ph2); 126.8 (s,
para-C, Ph, C(OH)Ph2); 124.9 (s, meta-C, Ph, C(OH)Ph2); C(OH)-
Ph2, CR and Câ are not seen in the spectrum. 19F NMR (CDCl3, δ):
1
2
2
δ): 15.3 (d, JPt1-P2 ) 2849.0, JPt2-P2 ≈ 60, JP1-P2 ) 22.4, P2
1
2
trans to CtC); 14.1 (d, JPt1-P1 ≈ 3250, JP1-P2 ) 22.4, P1 trans
to hydride). The complex is not soluble enough for 13C NMR.
Synthesis of [cis,cis-(PPh3)2Pt{µ-1κCR:η2-CHdCHC(OH)-
Ph2}(µ-OH)Pt(C6F5)2] (5f). Two drops of deoxygenated water were
added to a solution of 0.05 g (0.05 mmol) of [Pt{η2-HCtC(OH)-
Ph2}(PPh3)2] (2f) in CH2Cl2 (∼15 mL), and then 0.04 g (0.05 mmol)
of [cis-Pt(C6F5)2(thf)2] was also added to the mixture, which was
studied by 31P{1H} NMR. After 2 min the orange solution obtained
consists of a mixture of the (µ-hydride)(µ-alkynyl) complex [trans-
(PPh3)(C6F5)Pt(µ-H){µ-1κCR:η2-CtCC(OH)Ph2}Pt(C6F5)(PPh3)] (3f)
and the (µ-hydroxy)(µ-vinyl) complex [cis,cis-(PPh3)2Pt{µ-1κCR:
η2-CHdCHC(OH)Ph2}(µ-OH)Pt(C6F5)2] (5f) (molar ratio ∼20:80,
respectively) and traces of [cis,cis-(PPh3)2Pt(µ-H){µ-1κCR:η2-Ct
CC(OH)Ph2}Pt(C6F5)2] (4f). The solution was evaporated to small
volume (∼1 mL), and 5 mL of cold hexane was added, causing
(67) Takahashi, S.; Kuroyama, Y.; Sonogashira, K.; Hagihara, N.
Synthesis 1980, 627.
(68) Bailar, J. C.; Itatani, H. Inorg. Chem. 1965, 5, 1618.
(69) Saito, S.; Tando, K.; Kabuto, C.; Yamamoto, Y. Organometallics
2000, 19, 3740.
(70) Uso´n, R.; Fornie´s, J.; Toma´s, M.; Menjo´n, B. Organometallics 1985,
4, 1912.

Rearrangement Promoted by the SolVate [cis-Pt(C6F5)2(thf)2]
Organometallics, Vol. 26, No. 5, 2007 1171
the precipitation of 5f as a yellow solid. Yield: 0.06 g (77%). Anal.
Calcd for C63F10H44O2P2Pt2: C, 51.30; H, 3.01. Found: C, 51.09;
H, 2.99. MS ES(+): m/z 1052 [M - (C6F5) - (PPh3) - (H2O) +
Na + 2H]+ 13%; 910 [Pt(CCCPh2)(PPh3)2]+ 7%; 791 [M - (C6F5)
- 2(PPh3) - (H2O) + Na + 3H]+ 100% (sample ionized with
Na+). IR (cm-1): ν(OH) 3580 (m), 3562 (m); ν(CdC) 1603 (w);
ν(C6F5)x-sensitive 806 (m), 794 (m). 1H NMR (CDCl3, δ): 7.67, 7.46,
7.28, 7.15, 7.00, 6.89 (m, 40H, Ph, PPh3, and C(OH)Ph2); 6.46
(dd, 3JH-P ) 14.0, 3JH-H ) 7.4, 1H, µ-CRHdCâH); 5.85 (m, JH-Pt
≈ 60, 3JH-H ) 7.4, 1H, µ-CRHdCâH); 1.34 (s, 1H, OH); -0.33 (s,
1H, OH). 13C NMR (CDCl3, δ): 140-135 (C6F5); 146.2, 146.1 (s,
ipso-C, Ph, C(OH)Ph2); 134.4 (d, 2JC-P ) 11.2, ortho-C, Ph, PPh3);
intermediate [cis,cis-(PPh3)2Pt{µ-η2:η2-HCtC(OH)Ph2}Pt(C6F5)2-
(thf)] (6f) appeared and grew in intensity until 263 K (showing in
the 31P{1H} NMR spectrum the same relative intensity as that
observed in the study mentioned before without addition of water).
Above this temperature the signals due to 6f started to decrease in
intensity, while the resonances assigned to the (µ-hydroxy)(µ-vinyl)
complex 5f started to appear, which are the main signals observed
at 293 K. At this temperature the spectra also show the signals
assigned to 3f (3f:5f, 20:80 approximately) and 4f (trace).
Synthesis of [{(PPh3)2Pt(µ-η2:2κN-HCtCC5H4N-4)}2{cis-Pt-
(C6F5)2}] (7g). A suspension of 0.11 g (0.13 mmol) of [Pt(η2-HCt
CC5H4N-4)(PPh3)2] in 10 mL of CH2Cl2 was treated with 0.05 g
(0.07 mmol) of [cis-Pt(C6F5)2(thf)2], and the mixture was stirred at
room temperature for 5 min. The resulting yellow solution was
evaporated to dryness, and the residue was treated with hexane to
yield 4e as a yellow solid. Yield: 0.11 g (76%). Anal. Calcd for
C98F10H70N2P4Pt3: C, 54.12; H, 3.24; N, 1.29. The best analyses
found (C, 52.93; H, 2.74; N, 1.36) fit well with C98F10H70N2P4-
Pt3‚CH2Cl2: C, 52.62; H, 3.21; N, 1.24. MS ES(+): m/z 673
[Pt(C6F5)(HCtC5H4N)3 + 2H]+ 35%; 625 [Pt(C6F5)(PPh3) + H]+
100%; 568 [Pt(C6F5)(HCtC5H4N)2]+ 40%. IR (cm-1): ν(CtC)
1688 (m); ν(C6F5)x-sensitive 808 (m), 798 (m). 1H NMR (CDCl3, δ):
2
134.2 (d, JC-P ) 11.7, ortho-C, Ph, PPh3); 131.2 (s), 131.0 (s),
1
(para-C, Ph, PPh3); 129.2(d, JP-C ≈ 60, ipso-C, Ph, PPh3; this
signal, with the appearance of an overlapped doublet of doublets,
overlaps with the next signal); 128.8 (d, 3JP-C ) 10.2, meta-C, Ph,
3
PPh3); 128.5 (d, JP-C ) 11.6, meta-C, Ph, PPh3; This signal
probably overlaps with a signal due to para-C of C(OH)Ph2); 128.2,
127.6, 127.0, 126.1 (para-C); 126.0 (s, Ph, C(OH)Ph2); 117.6 (CR,
4
CdC); 105.0 (Câ, CdC); 77.9 (d, JP-C ) 6.7, C(OH)Ph2). 19F
NMR (CDCl3, δ): -114.94 (d, 3JPt-F ≈ 400, 1ortho-F); -118.76
3
3
(d, JPt-F ≈ 400, 1ortho-F); -119.26 (d, JPt-F ≈ 420, 2ortho-F);
-162.04 (t, 1para-F); -162.74 (t, 1para-F); -164.53 (m, 2meta-
F); -164.85 (m, 1meta-F); -165.34 (m, 1meta-F). 31P NMR
(CDCl3, δ): 22.8 (d, 1JPt-P2 ) 1619.0, 2JP1-P2 ) 14.5, P2 trans to
3
3
7.86 (d, JH-H ) 5.7, 4H3, C5H4N); 7.51 (dd, JPtrans-H ) 21.1,
3JPcis-H ) 12.0, 2H, tCH; this signal partially overlaps with the
next one; platinum satellites are observed, but JPt-H cannot be
2
1
2
unambiguously calculated); 7.24, 7.13, 7.00 (m, 60H, PPh3); 6.57
CHdCH); 8.1 (d, JPt-P1 ) 4272.0, JP1-P2 ) 14.5, P1 trans to
3
(d, JH-H ) 5.7, 4H2, C5H4N). 13C NMR (CDCl3, δ): 151-137
hydroxy). 195Pt NMR (CDCl3, δ): -4240 (dd, JPt1-P1 ≈ 4300,
1
3
(m br, C6F5); 150.0 (s, C3, C5H4N); 143.5 (“t”, 3JPtrans-C ≈ JPcis-C
1JPt1-P2 ≈ 1900, Pt1); the signal due to Pt2 is not observed probably
≈ 9, C1, C5H4N); ∼136 (overlapping of two doublets of doublets
due to the ipso-C of PPh3); 133.9 (d, 2JC-P ) 13.1, 3JC-Pt ) 20.2,
overlapping of two practically isochronous doublets, with similar
because of the coupling with the ortho-F of the C6F5 groups.
Study of the Reaction between [Pt{η2-HCtCC(OH)Ph2}-
(PPh3)2] (2f) and [cis-Pt(C6F5)2(thf)2] at NMR Scale. This reaction
was not done in anhydrous conditions. [cis-Pt(C6F5)2(thf)2] (0.013
g, 0.02 mmol) was added, at 223 K, to a solution of [Pt{η2-HCt
C(OH)Ph2}(PPh3)2] (2f) (0.019 g, 0.02 mmol) in 1 mL of CDCl3,
and the mixture was studied by multinuclear NMR spectroscopy
(1H, 19F, and 31P{1H}). On raising the temperature, the resonances
due to the starting materials decreased in their relative intensity,
while signals corresponding to a unique, new compound, which
has been identified as the mixed-valence intermediate [cis,cis-
(PPh3)2Pt{µ-η2:η2-HCtC(OH)Ph2}Pt(C6F5)2(thf)] (6f), appeared,
and they grew in intensity until 263 K. Above this temperature,
the signals due to 6f started to decrease in intensity, while the
resonances assigned to the (µ-hydroxy)(µ-vinyl) com-
plex [cis,cis-(PPh3)2Pt{µ-1κCR:η2-CHdCHC(OH)Ph2}(µ-OH)Pt-
(C6F5)2] (5f) appeared. The signals corresponding to the (µ-hydride)-
(µ-acetylide) isomers [trans-(PPh3)(C6F5)Pt(µ-H){µ-1κCR:η2-Ct
CC(OH)Ph2}Pt(C6F5)(PPh3)] (3f) and [cis,cis-(PPh3)2Pt(µ-H){µ-
1κCR:η2-CtCC(OH)Ph2}Pt(C6F5)2] (4f) were observed for the first
time at 283 K. At 293 K, the reaction mixture consists of an
approximately equimolecular mixture of 3f and 5f, together with a
small amount (less than 10%) of 4f. At this temperature there are
also still signals due to the alkyne Pt(0) precursor 2f. Spectroscopic
data for 6f at 263 K: 1H NMR (CDCl3, δ): 5.97 (dd, 2JH-Pt ≈ 47,
3JH-Ptrans ≈ 24, 3JH-Pcis ≈ 7, tCH). 19F NMR (CDCl3, δ): -117.4
4
J, due to the ortho-C of PPh3); 129.61 (d, JP-C ≈ 2.5, para-C,
4
3
PPh3); 129.57 (d, JP-C ≈ 2.4, para-C, PPh3); 128 (d“t”, JC-P
≈
10,5JC-P ≈ 1.4, overlapping of two practically isochronous doublets,
4
with similar J, due to the meta-C of PPh3); 125.4 (“t”, JP-C ≈ 4,
3JPt-C ≈ 30, C2, C5H4N). The signals due to CR and Câ are not
observed. 19F NMR (CDCl3, δ): -120.48 (d, 3JPt-F ≈ 470, 4ortho-
F); -163.66 (t, 2para-F); -165.52 (m, 4meta-F). 31P NMR (CDCl3,
δ): 27.3 (d, 1JPt-P ) 3477.8, 2JP-P ) 26.8); 25.8 (d, 1JPt-P ) 3587.8,
2JP-P ) 26.8).
X-ray Crystallography. Table 4 reports details of the structural
analyses for all complexes studied. Pale yellow (1b), colorless (3a,
4c, 5f), yellow (3b, 4a), or orange (4e) crystals were obtained by
slow diffusion of n-hexane into chloroform (3a, 4e, and 5f, room
temperature), dichloromethane (3b, 4a, and 4c, room temperature),
or acetone (1b, -30 °C) solutions of each compound. For complex
4a one molecule of CH2Cl2 and one of water, for complex 4c one
and a half molecules of CH2Cl2, and for complex 4e one molecule
of CHCl3 were found in the asymmetric unit. X-ray intensity data
were collected with a NONIUS κCCD area-detector diffractometer,
using graphite-monochromated Mo KR radiation. Images were
processed using the DENZO and SCALEPACK suites of pro-
grams,71 carrying out the absorption correction at this point for
complexes 1b, 3a, and 3b. For the rest of the complexes, the
absorption correction was performed using SORTAV.72 The
structures of 4e‚CHCl3 and 5f were solved by Patterson or direct
methods, respectively, using the SHELXL-97 program,73 while the
rest of the structures were solved by Patterson and Fourier methods
using the DIRDIF92 program.74 All structures were refined by full-
3
3
(d, JPt-F ≈ 360, 2ortho-F); -119.6 (d, JPt-F ≈ 400, 2ortho-F);
-161.4 (t, 1para-F); -161.9 (t, 1para-F); -163.3 (m, 2meta-F);
-164.2 (m, 2meta-F). 31P NMR (CDCl3, δ): 32.2 (d, 1JPt-P ) 3665,
2JP-P ) 14); 27.9 (d, JPt-P ) 3571.8, JP-P ) 14).
1
2
Study of the Reaction between [Pt{η2-HCtCC(OH)Ph2}-
(PPh3)2] (2f) and [cis-Pt(C6F5)2(thf)2] with Addition of Water
at NMR Scale. [cis-Pt(C6F5)2(thf)2] (0.013 g, 0.02 mmol) was added
at 223 K to a solution of [Pt{η2-HCtC(OH)Ph2}(PPh3)2] (2f) (0.019
(71) Otwinowski, Z.; Minor, W. In Methods in Enzymology; Carter, C.
V., Jr., Sweet, R. M., Eds.; Academic Press: New York, 1997; Vol. 276A,
p 307.
(72) Blessing, R. H. Acta Crystallogr. 1995, A51, 33.
(73) Sheldrick, G. M. SHELX-97, a program for the refinement of crystal
structures; University of Go¨ttingen: Germany, 1997.
(74) Beursken, P. T.; Beursken, G.; Bosman, W. P.; de Gelder, R.; Garc´ıa-
Granda, S.; Gould, R. O.; Smith, J. M. M.; Smykalla, C. The DIRDIF92
program system; Technical Report of the Crystallography Laboratory;
University of Nijmegen: The Netherlands, 1992.
g, 0.02 mmol) and two drops of water in
1 mL of
CDCl3, and the mixture was studied by multinuclear NMR
spectroscopy (1H, 19F, and 31P{1H}). On raising the temperature,
the resonances due to the starting materials decreased their relative
intensity, while the signals corresponding to the mixed-valence

1172 Organometallics, Vol. 26, No. 5, 2007
Berenguer et al.
Table 4. Crystallographic Data for 1b, 3a, 3b, 4a, 4c, 4e, and 5f
1b
3a
3b
empirical formula
fw
C42H35NP2Pt
846.77
C57H37F10P2Pt2
1363.99
C57H35F10NP2Pt2
1375.98
temperature (K)
cryst syst
space group
a (Å)
b (Å)
c (Å)
123(1)
monoclinic
C2/c
15.5902(3)
16.2396(4)
15.3325(4)
90
113.620(1)
90
3556.65(14)
4
1.581
4.0696
1680
293(2)
monoclinic
P21/c
23.6302(2)
14.7458(3)
28.5730(5)
90
150.658(1)
90
4878.72(14)
4
1.857
5.872
2620
293(2)
monoclinic
P21/c
23.2380(1)
14.8000(2)
28.1530(2)
90
149.6591(6)
90
4891.02(8)
4
1.869
5.858
2640
R (deg)
â (deg)
γ (deg)
volume (Å3)
Z
D
calcd (Mg/m3)
abs coeff (mm-1
F(000)
)
cryst size (mm)
0.70 × 0.40 × 0.40
2.95 to 27.90
4197/0/223
1.018
0.50 × 0.05 × 0.05
5.13 to 25.68
9174/0/641
0.999
0.60 × 0.10 × 0.075
4.12 to 27.10
10 743/0/653
1.003
θ range for data collection (deg)
no. of data/restrains/params
goodness-of-fit on F2
final R indices [I > 2σ(I)]
R1 ) 0.0273,
wR2 ) 0.0671
R1 ) 0.0305,
wR2 ) 0.0698
1.440 and -1.497
R1 ) 0.0504,
wR2 ) 0.0771
R1 ) 0.1186,
wR2 ) 0.0938
0.805 and -0.687
R1 ) 0.0344,
wR2 ) 0.0620
R1 ) 0.0634,
wR2 ) 0.0702
1.089 and -0.705
R indices (all data)
largest diff peak and hole (e‚A-3
)
4a‚CH2Cl2‚H2O
4c‚1.5CH2Cl2
54.5H38Cl3F10P2Pt2
4e‚CHCl3
5f
empirical formula
fw
C58H40Cl2F10OP2Pt2
1465.92
C
C55H40Cl3F10OP2Pt2
1465.34
C63H44F10O2P2Pt2
1475.10
1441.32
temperature (K)
cryst syst
space group
a (Å)
b (Å)
c (Å)
293(2)
triclinic
P1h
173(1)
orthorhombic
Pcab
17.3760(2)
24.1390(2)
25.1940(2)
90
293(2) K
triclinic
P1h
173(1)
monoclinic
P2/c
22.44670(1)
10.9348(1)
24.7410(2)
90
116.5999(4)
90
5429.92(7)
4
1.804
5.286
2856
12.4140(3)
13.7921(3)
17.2697(5)
79.742(1)
74.228(1)
73.240(1)
2708.64(12)
2
13.7330(5)
14.6640(5)
16.6710(7)
64.420(2)
88.728(2)
64.725(2)
2683.61(17)
2
R (deg)
â (deg)
90
90
γ (deg)
volume (Å3)
Z
10567.35(17)
8
1.812
5.573
5536
D
calcd (Mg/m3)
1.797
5.391
1412
1.813
5.490
1410
abs coeff (mm-1
F(000)
)
cryst size (mm)
0.15 × 0.10 × 0.05
4.11 to 27.87
12 838/0/682
1.041
0.15 × 0.10 × 0.075
4.08 to 25.68
9996/8/639
1.007
0.25 × 0.25 × 0.10
4.10 to 24.43
8292/0/661
1.026
0.35 × 0.27 × 0.25
2.12 to 28.72
14 048/0/724
1.028
θ range for data collection (deg)
no. of data/restrains/params
goodness-of-fit on F2
final R indices [I > 2σ(I)]
R1 ) 0.0480,
wR2 ) 0.0995
R1 ) 0.0845,
wR2 ) 0.1089
1.075 and -1.121
R1 ) 0.0456,
wR2 ) 0.1163
R1 ) 0.0714,
wR2 ) 0.1286
2.614 and -1.724
R1 ) 0.0683,
wR2 ) 0.1621
R1 ) 0.1106,
wR2 ) 0.1901
1.761 and -2.214
R1 ) 0.0302,
wR2 ) 0.0610
R1 ) 0.0479,
wR2 ) 0.0659
0.850 and -1.094
R indices (all data)
largest diff peak and hole (e‚A-3
)
matrix least-squares on F2 with SHELXL-97,73 and all non-
hydrogen atoms were assigned anisotropic displacement parameters.
The hydride ligand H(1) in 1b, 3b, and 4a‚CH2Cl2‚H2O, as well as
the hydroxyl H(1) and the vinyl H(13,14) protons in 5f, have been
located from difference maps and assigned isotropic parameters.
The rest of the hydrogen atoms were constrained to idealized
geometries fixing isotropic displacement parameters of 1.2 times
the Uiso value of their attached carbon for the aromatic and CH2
hydrogens and 1.5 times Uiso for the methyl groups. For complex
4c‚1.5CH2Cl2, the methyl and methylenic groups of the vinylic
fragment present positional disorder, which could be refined over
two positions with partial occupancy factors of 0.50. In this
structure, the CH2Cl2 was also disordered and modeled adequately.
Complex 4e possesses a chiral center at the Cγ atom of the acetylide
ligand with both of the enantiomers, R and S, present in the unit
cell (Figure S1c in the Supporting Information shows the enantiomer
S). Finally, for complexes 1b, 3b, 4a‚CH2Cl2‚H2O, 4c‚1.5CH2Cl2,
and 4e‚CHCl3 some residual peaks larger than 1 e Å-3 were
observed in the vicinity of the heavy atoms or the disorder solvents,
but with no chemical significance.
Acknowledgment. We wish to thank the Ministerio de
Ciencia y Tecnolog´ıa, Spain, and the European Regional
Development Fund (Project CTQ2005-08606-C02-02/BQU) for
financial support. M.B. wishes to thank the CAR for a grant.
We would like to thank Professor J. Fornie´s for helpful
discussions and encouragement.
Supporting Information Available: Selected bond lengths and
angles for complexes 3a, 4c, and 4e and the view of their molecular
structures. 1H and 31P{1H} NMR spectra of complexes 3a and 4a.
1H NMR and heteronuclear C,H correlation spectra of 5f. Study of
the reaction of [Pt{η2-HCtC(OH)Ph2}(PPh3)2] with [cis-Pt(C6F5)2-
(THF)2] without addition of water by NMR at different tempera-
tures. Further crystallographic data of 1b, 3a, 3b, 4a‚CH2Cl2‚H2O,
4c‚1.5CH2Cl2, 4e‚CHCl3, and 5f are given in CIF format. This
material is available free of charge via the Internet at http://
pubs.acs.org.
OM060977Y