New mono- and polynuclear alkynyl complexes containing phenylacetylide as terminal or bridging ligand. X-ray structures of the compounds NBu 4[Pt(CH2C6H4P(o-tolyl) 2-κC,P)(C=CPh)2], [Pt(CH2C 6H4P(o-tolyl)2-κC,P)(C=CPh)(CO)], [{Pt(CH2C6H4P(o-...

Article abstract of DOI:10.1021/om061102m

Full title: New mono- and polynuclear alkynyl complexes containing phenylacetylide as terminal or bridging ligand. X-ray structures of the compounds NBu ₄[Pt(CH₂C₆H₄P(o-tolyl) ₂-κC,P)(C=CPh)₂], [Pt(CH₂C ₆H₄P(o-tolyl)₂-κC,P)(C=CPh)(CO)], [{Pt(CH₂C₆H₄P(o-tolyl)₂-κC,P) (μ-C=CPh)}₂], and [{Pt(CH₂C₆H ₄P(o-tolyl)₂-κC,P)(C=CPh)₂Cu} ₂]. This work describes the synthesis of the compounds Q[Pt(CΛP) (C≡CPh)₂] (Q - Li⁺ (1), NBu₄⁺ (2). CΛP = CH₂C₆H₄P(o-tolyl)2-κC, P) and their use as precursors for the preparation of homo- and heteropolynuclear complexes by reactions with Lewis acid species of transition metals, M (M = Cu(I), Ag(I), Tl(I), Pd(II), Pt(II)). These reactions give rise to heteropolynuclear complexes that exhibit different bonding patterns for the bridging alkynyl ligands, depending on M. The reaction of 2 with readily available M⁺ (M = Cu, Ag) species affords the discrete tetranuclear clusters [{Pt(CΛP)(C≡CPh)₂M}₂] (M = Cu (3), Ag (4)). The X-ray structure of 3 shows that in this complex both "Pt(CΛP)(C≡CPh)₂" fragments are connected by two d¹⁰ metal centers and are stabilized by alkynyl bridging ligands, showing the stronger preference of the M^I centers (M^I = Cu, Ag) for the electron-rich alkynyl units than for the basic Pt(II) center. However, the reaction of 2 with TlPF₆ rendered the tentatively tetranuclear complex [{Pt(CΛP)-(C≡CPh)₂Tl}₂] (5), containing Pt→Tl dative bonds, which shows the higher affinity of thallium for the electron density of platinum(II) than for the alkynyl units. Moreover, the reaction of (NBu₄)[Pt(CΛP)-(C≡CPh) ₂] (2) with the neutral complex [Pd(C₆F₅) ₂(THF)₂] yields the compound (NBu₄) [Pt(CΛP)(C≡CPh)2Pd(C₆F₅)₂] (11), in which the two alkynyl ligands are η²-bonded to Pd(II) in such a way that the "cis-Pt(C≡CPh)₂" fragment acts as a chelate ligand toward Pd(II). Meanwhile the reactions with the cationic and neutral Pt(II) complexes [Pt(CΛP)(THF)₂]⁺ and [Pt(C₆F₅)₂(THF)₂] produce the complexes [{Pt(CΛP)-(μ-C≡CPh)}₂] (6) and (NBu ₄)[Pt(CΛP)(μ-C≡CPh)₂Pt(C₆F ₅)₂] (12), both containing the double μ₂- η²-(σ,π)-alkynyl bridging system "Pt ₂(μ-C≡CPh)₂" as a consequence of an alkynylating process. This bridging system "Pt₂(μ- C≡CPh)₂" can be broken by neutral ligands, L, to give mono(σ-alkynyl) complexes of Pt(II). Thus, the complexes [Pt(CΛP)(C≡CPh)L] (L = CO (7), py (8), tht (9), PPh₃ (10)) have been obtained by reaction of 6 with L in a 1:2 molar ratio. When L = PPh₃, the substitution reaction takes place with stereoretention, but not when L = CO, py, tht, as was conclusively established by an X-ray study on the complex [Pt(CH₂C₆H₄P(o-tolyl) ₂)(CCPh)(CO)] (7). The cis or trans disposition of the two σ-C-donor ligands (C(CΛP), σ-C≡CPh) around the Pt center in complexes 6-10 and 12 seems to depend as much on the transphobia of pairs of trans ligands (T) as on the steric requirements of those in the cis configuration.

Full text of DOI:10.1021/om061102m

1674
Organometallics 2007, 26, 1674-1685
New Mono- and Polynuclear Alkynyl Complexes Containing
Phenylacetylide as Terminal or Bridging Ligand. X-ray Structures
of the Compounds NBu4[Pt(CH2C6H4P(o-tolyl)2-KC,P)(CtCPh)2],
[Pt(CH2C6H4P(o-tolyl)2-KC,P)(CtCPh)(CO)],
[{Pt(CH2C6H4P(o-tolyl)2-KC,P)(µ-CtCPh)}2], and
[{Pt(CH2C6H4P(o-tolyl)2-KC,P)(CtCPh)2Cu}2]
Jose´ M. Casas,† Juan Fornie´s,*,† Sara Fuertes,† Antonio Mart´ın,† and Violeta Sicilia*,‡
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n, Facultad de
Ciencias, UniVersidad de Zaragoza-CSIC, Plaza. S. Francisco s/n 50009 Zaragoza, Spain, and
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Escuela UniVersitaria de Ingenier´ıa Te´cnica Industrial, UniVersidad de Zaragoza-CSIC,
Campus UniVersitario del Actur, Edificio Torres QueVedo, 50018 Zaragoza, Spain
ReceiVed December 4, 2006
This work describes the synthesis of the compounds Q[Pt(C∧P)(CtCPh)2] (Q ) Li+ (1), NBu4+ (2).
C∧P ) CH2C6H4P(o-tolyl)2-κC,P) and their use as precursors for the preparation of homo- and
heteropolynuclear complexes by reactions with Lewis acid species of transition metals, M (M ) Cu(I),
Ag(I), Tl(I), Pd(II), Pt(II)). These reactions give rise to heteropolynuclear complexes that exhibit different
bonding patterns for the bridging alkynyl ligands, depending on M. The reaction of 2 with readily available
M+ (M ) Cu, Ag) species affords the discrete tetranuclear clusters [{Pt(C∧P)(CtCPh)2M}2] (M ) Cu
(3), Ag (4)). The X-ray structure of 3 shows that in this complex both “Pt(C∧P)(CtCPh)2” fragments
are connected by two d10 metal centers and are stabilized by alkynyl bridging ligands, showing the stronger
preference of the MI centers (MI ) Cu, Ag) for the electron-rich alkynyl units than for the basic Pt(II)
center. However, the reaction of 2 with TlPF6 rendered the tentatively tetranuclear complex [{Pt(C∧P)-
(CtCPh)2Tl}2] (5), containing PtfTl dative bonds, which shows the higher affinity of thallium for the
electron density of platinum(II) than for the alkynyl units. Moreover, the reaction of (NBu4)[Pt(C∧P)-
(CtCPh)2] (2) with the neutral complex [Pd(C6F5)2(THF)2] yields the compound (NBu4)[Pt(C∧P)(CtCPh)2-
Pd(C6F5)2] (11), in which the two alkynyl ligands are η2-bonded to Pd(II) in such a way that the “cis-
Pt(CtCPh)2“ fragment acts as a chelate ligand toward Pd(II). Meanwhile the reactions with the cationic
and neutral Pt(II) complexes [Pt(C∧P)(THF)2]+ and [Pt(C6F5)2(THF)2] produce the complexes [{Pt(C∧P)-
(µ-CtCPh)}2] (6) and (NBu4)[Pt(C∧P)(µ-CtCPh)2Pt(C6F5)2] (12), both containing the double µ2-η2-
(σ,π)-alkynyl bridging system “Pt2(µ-CtCPh)2” as a consequence of an alkynylating process. This bridging
system “Pt2(µ-CtCPh)2” can be broken by neutral ligands, L, to give mono(σ-alkynyl) complexes of
Pt(II). Thus, the complexes [Pt(C∧P)(CtCPh)L] (L ) CO (7), py (8), tht (9), PPh3 (10)) have been
obtained by reaction of 6 with L in a 1:2 molar ratio. When L ) PPh3, the substitution reaction takes
place with stereoretention, but not when L ) CO, py, tht, as was conclusively established by an X-ray
study on the complex [Pt(CH2C6H4P(o-tolyl)2)(CCPh)(CO)] (7). The cis or trans disposition of the two
σ-C-donor ligands (C(C∧P), σ-CtCPh) around the Pt center in complexes 6-10 and 12 seems to depend
as much on the transphobia of pairs of trans ligands (T) as on the steric requirements of those in the cis
configuration.
in supramolecular chemistry and material science.3-6 Within
this field, square-planar platinum(II) σ-acetylide complexes have
attracted much attention in nonlinear optics,7 photochemical
devices,8-13 luminiscence,14-21 liquid crystals,22,23 molecular
wires,24-26 macrocycles,27,28 and dendritic molecules.10,29
Platinum σ-alkynyl complexes with linear Pt-CtCR groups
have been used as excellent precursors for the synthesis of
Introduction
The chemistry of transition-metal alkynyl complexes and
polymers has been intensively studied due to their structural
diversity and chemical reactivity.1,2 Interest has grown, par-
ticularly in recent years, because of their potential application
* To whom correspondence should be addressed. J.F.: fax, (+34)976-
761159; e-mail, juan.fornies@unizar.es. V.S.: fax, (+34)976-762189; e-mail,
sicilia@unizar.es.
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‡ Escuela Universitaria de Ingenier´ıa Te´cnica Industrial, Universidad de
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Publication on Web 02/20/2007

Mono- and Polynuclear Alkynyl Complexes
Organometallics, Vol. 26, No. 7, 2007 1675
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1676 Organometallics, Vol. 26, No. 7, 2007
Casas et al.
Scheme 1a
n
n
a Legend: (a) BuLi (excess); (b) NBu4Br; (c) [Cu(NCMe)4]PF6; (d) AgClO4; (e) TlPF6; (f) [Pt(C∧P)(THF)2]ClO4; (g) BuLi; (h) L ) CO, py,
tht; (i) PPh3; (j) cis-[Pd(C6F5)2(THF)2]; (k) cis-[Pt(C6F5)2(THF)2].
The reactions of the neutral complexes cis-[PtL2(CtCR)2]
with [M(C6F5)2(THF)2] (M ) Pd, Pt), which contain two weak
donor ligands (THF) in cis positions easily replaceable by other
ones, render dinuclear derivatives of types A65,66 and F66
meanwhile the anionic complexes Q2[cis-Pt(C6F5)2(CtCR)2] (R
“Pt(C∧P)” metallacycle and alkynyl ligands. As part of this
work, we have prepared the monoanionic bis(σ-alkynyl)-
platinum(II) complex [Pt(C∧P)(CtCPh)2]-, in which the alky-
nyl ligands and the platinum center are all electron density rich.
Its reactions with transition-metal species, M (M ) Cu(I),
Ag(I), Tl(I), Pd(II), Pt(II)) yielded new polynuclear complexes
exhibiting different bonding patterns for the bridging alkynyl
groups, depending on M.
t
) Ph, Q ) PMePh3; R ) Bu, Q ) NBu4)65 give compounds
of type G, as a consequence of an alkylating process of the
“M(C6F5)2” fragment. However, both the neutral complexes cis-
[PtL2(CtCR)2] and the anionic [cis-Pt(C6F5)2(CtCR)2]2- give
compounds of type A when they react with the cationic “Pd-
(η3-C3H5)+” species.67,69
Results and Discussion
Synthesis and Spectroscopic Characterization of the
Compounds Q[Pt(C∧P)(CtCPh)2] (Q ) Li+ (1), NBu4+ (2)).
The compound Li[Pt(C∧P)(CtCPh)2] (1) was prepared by
treating a suspension of the dinuclear chloro-bridged complex
[{Pt(C∧P)(µ-Cl)}2] with LiCtCPh in THF at low temperature
(Scheme 1a, see the Experimental Section for details).
If NBu4Br is added to a freshly prepared solution of 1 in
iPrOH (see the Experimental Section), the compound (NBu4)-
[Pt(C∧P)(CtCPh)2] (2) precipitates “in situ” (Scheme 1b).
Compounds 1 and 2 were obtained as air-stable solids and fully
characterized by the usual analytical and spectroscopic means
As part of our current research on polynuclear complexes,
we have recently described the synthesis of neutral Pt(II)
complexes of the formulas [Pt(C∧P)(L∧L)] (C∧P ) CH2C6H4P-
(o-tolyl)2-κC,P, L∧L ) S2CNMe2, S2COEt, acac-O,O′), [{Pt-
(C∧P)(µ-O2CCX3)}2] (X ) H, F), and [{Pt(C∧P)(µ-Rpz)}2]
(Rpz ) pz, 3,5-dmpz, 4-Mepz) and we demonstrated their ability
to form heteronuclear compounds containing PtfM donor-
acceptor bonds when they react with Lewis acids such as
Ag(I), Au(I), and Hg(II) species.71-76
With the aim of obtaining new polynuclear complexes, we
decided to prepare compounds that simultaneously contain the
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4238.

Mono- and Polynuclear Alkynyl Complexes
Organometallics, Vol. 26, No. 7, 2007 1677
Table 1. IR and 31P{1H} NMR Data for Compounds 1-13
complex
δ(P) (ppm)
32.0 (s)
1JPt-P (Hz)
∆P (ppm)e
∆JPt-P (Hz)f
ν
CtC (cm-1
)
Li[Pt(C∧P)(CtCPh)2] (1)a
NBu4[Pt(C∧P)(CtCPh)2] (2)a
[{Pt(C∧P)(CtCPh)2Cu}2] (3)a
[{Pt(C∧P)(CtCPh)2Ag}2] (4)b
[{Pt(C∧P)(CtCPh)2Tl}2] (5)a
[{Pt(C∧P)(CtCPh)}2] (6)c
[Pt(C∧P)(CtCPh)(CO)] (7)a
[Pt(C∧P)(CtCPh)(py)] (8)a
[Pt(C∧P)(CtCPh)(tht)] (9)d
[Pt(C∧P)(CtCPh)(PPh3)] (10)b
2746
2603
3056
3015
2681
4190
2448
2742
2696
2913
0.2
143
2078
31.8 (s)
30.2 (s)
29.2 (s)
29.3 (s)
25.1 (s)
33.6 (s)
35.4 (s)
31.9 (s)
32.6 (νA)
25.6 (νB)
JA-B ) 433 Hz
33.3 (s)
27.9 (s)
16.5 (s)
2098, 2081
2007, 1971
2019
2088, 2059
1962
2127
2102
2103
2094
-1.6
-2.6
-2.5
-6.7
+1.8
+3.6
+0.1
+0.8
453
412
78
1587
-155
139
93
310
(NBu4)[Pt(C∧P)(CtCPh)2Pd(C6F5)2] (11)a
(NBu4)[Pt(C∧P)(CtCPh)2Pt (C6F5)2] (12)a
(NBu4)[Pt(C6F5)2(CtCPh)(PPh3)] (13)b
3013
4223
2543
+1.5
-3.9
410
1620
2033
1957
2104
a Conditions: 300 MHz, CD2Cl2, 293 K. b Conditions: 400 MHz, CD2Cl2, 293 K. c Conditions; 300 MHz, CDCl3, 328 K. d Conditions: 300 MHz,
CDCl3, 293 K. e ∆P (ppm) ) δ(P)- δ(P(2)). f ∆JPt-P (Hz) ) JPt-P - JPt-P(2).
center is bonded to two alkynyl carbon atoms and to the
phosphorus and carbon donor atoms of the C,P-cyclometalated
phosphine ligand, showing a distorted-square-planar geometry.
Structural parameters concerning the five-membered metalla-
cycle are similar to those observed in other complexes containing
it.71-76,78 The Pt-Cacetylide bond lengths observed are identical
within experimental error, in spite of the different trans donor
atoms (C or P). These distances are similar to those observed
in (NBu4)[Pt(bzq)(CtCC5H4N-2)2]14 and slightly longer than
those reported for some neutral bis(acetylide) complexes.15,79-81
The alkynyl groups lie in the platinum coordination plane82 and
show the expected linear arrangement.
Heteropolynuclear complexes containing alkynyl bridging
ligands connecting metals and lithium centers have been
previously reported.38,83-86 In compound 1, the singlet observed
in its 7Li NMR spectrum proves the presence of the alkali metal.
For this compound a structure of the anion similar to that
described for 2 can be proposed on the basis of the analytical
and spectroscopic data. The observed small shift of the νCtC
absorption to a lower wavenumber, the small enlargement of
the Pt-P coupling constant with respect to compound 2 (Table
1), and the absence of Pt-Li coupling in the 7Li NMR spectrum
of 1, even at 193 K in CD2Cl2,38,83 denote that a very weak
interaction, if any, occurs between the Li+ and the alkynyl
fragments or platinum. In spite of the structural similarities of
these two compounds, 2 is stable in dichloromethane solution
at room temperature for a long time, while under the same
conditions, 1 decomposes in 1 h to give [{Pt(C∧P)(µ-Ct
CPh)}2] (6), which will be described in full below.
Figure 2. Molecular structure of the anion of compound 2.
Table 2. Selected Bond Distances (Å) and Angles (deg) for
NBu4[Pt(C∧P)(CtCPh)2] (2)
Pt-C1
Pt-C23
C(1)-C(2)
1.973(5)
2.097(4)
1.198(6)
Pt-C9
1.998(5)
2.2501(13)
1.213(5)
Pt-P(1)
C(9)-C(10)
C(1)-Pt-C(9)
C(9)-Pt-P(1)
Pt-C(1)-C(2)
Pt-C(9)-C(10)
91.66(18)
99.37(13)
174.7(4)
C(1)-Pt-C(23)
C(23)-Pt-P(1)
C(1)-C(2)-C(3)
C(9)-C(10)-C(11)
88.20(17)
80.82(12)
175.8(12)
178.9(6)
177.5(4)
(see the Experimental Section). Both complexes give the
expected negative ion [M - Q]- (∼100%) in their FAB mass
spectra, and conductivity measurements in acetone confirm their
behavior as 1:1 electrolytes.77 The observation of two νCtC
absorptions (Table 1) in the IR spectrum of compound 2 is
consistent with a cis arrangement of the σ-alkynyl ligands around
the Pt(II) center,14,16 which was later confirmed by X-ray
crystallography. In the 13C NMR spectrum of 2 the expected
signals for two alkynyl ligands are present. The signals due to
the CR and Câ atoms corresponding to the alkynyl group located
trans to the P atom are found at higher field. These sig-
nals appear as doublets because of the P-C coupling and
The anionic complex [Pt(C∧P)(CtCPh)2]- contains two
alkynyl groups and a basic metal center, all electron density
rich. Thus, it is capable of coordinating to acidic species through
(78) Fornie´s, J.; Mart´ın, A.; Navarro, R.; Sicilia, V.; Villarroya, P.
Organometallics 1996, 15, 1826.
(79) Chan, S. C.; Chan, M. C. W.; Wang, Y.; Che, C. M.; Cheung, K.
K.; Zhu, N. Chem. Eur. J. 2001, 7, 4180.
(80) McGarrah, J. E.; Kim, Y.-J.; Hissler, M.; Eisenberg, R. Inorg. Chem.
2001, 40, 4510.
(81) Whittle, C. E.; Weinstein, J. A.; George, M. W.; Schanze, K. S.
Inorg. Chem. 2001, 40, 4053.
(82) Nardelli, M. Comput. Chem. 1983, 7, 95.
(83) Sebald, A.; Wrackmeyer, B.; Theocharis, C. R.; Jones, W. J. Chem.
Soc., Dalton Trans. 1984, 747.
(84) Varga, V.; Mach, K.; Hiller, J.; Thewalt, U. J. Organomet. Chem.
1996, 506, 109.
(85) Vaid, T. P.; Veige, A. S.; Lobkovsky, E. M.; Glassey, W. V.;
Wolczanski, P. T.; Liable-Sands, L. M.; Rheingold, A. L.; Cundari, T. R.
J. Am. Chem. Soc. 1998, 120, 10067.
(86) Goldfuss, B.; Schleyer, P. V. R.; Hampel, F. J. Am. Chem. Soc.
1997, 119, 1072.
1
2
show larger values for JPt-C and JPt-C as a result of the
smaller trans influence of P with respect to the cyclometalated
C atom.14
The X-ray structure of 2 (Figure 2, Table 2) shows that in
the anionic complex [Pt(C∧P)(CtCPh)2]- the platinum(II)
(77) Geary, W. J. Coord. Chem. ReV. 1971, 81, 7.

1678 Organometallics, Vol. 26, No. 7, 2007
Casas et al.
Table 3. Selected Bond Distances (Å) and Angles (deg) for
[{Pt(C∧P)(CtCPh)2Cu}2] (3)
Pt(1)-C(1)
2.004(4)
2.090(4)
2.007(4)
2.105(4)
2.007(4)
1.996(4)
1.970(4)
2.005(4)
1.235(6)
1.222(6)
3.1793(5)
2.9436(6)
3.0358(7)
Pt(1)-C(9)
Pt(1)-P(1)
2.023(4)
2.2574(11)
2.018(5)
2.2654(11)
2.106(4)
2.132(4)
2.098(4)
2.128(4)
1.214(6)
1.245(6)
3.1569(5)
3.0413(5)
Pt(1)-C(23)
Pt(2)-C(38)
Pt(2)-C(60)
Cu(1)-C(1)
Cu(1)-C(46)
Cu(2)-C(9)
Cu(2)-C(38)
C(1)-C(2)
Pt(2)-C(46)
Pt(2)-P(2)
Cu(1)-C(2)
Cu(1)-C(47)
Cu(2)-C(10)
Cu(2)-C(39)
C(9)-C(10)
C(46)-C(47)
Pt(1)-Cu(2)
Pt(2)-Cu(2)
C(38)-C(39)
Pt(1)-Cu(1)
Pt(2)-Cu(1)
Cu(1)-Cu(2)
C(1)-Pt(1)-C(9)
C(9)-Pt(1)-P(1)
C(38)-Pt(2)-C(46)
C(46)-Pt(2)-P(2)
Pt(1)-C(1)-C(2)
Pt(1)-C(9)-C(10)
96.25(17) C(1)-Pt(1)-C(23)
95.28(12) C(23)-Pt(1)-P(1)
92.88(17) C(38)-Pt(2)-C(60)
96.71(13) C(60)-Pt(2)-P(2)
85.76(17)
82.82(12)
89.26(17)
81.31(13)
168.1(4)
172.9(4)
176.1(4)
C(1)-C(2)-C(3)
Figure 3. Molecular structure of compound 3.
C(9)-C(10)-C(11)
C(38)-C(39)-C(40) 165.8(4)
C(46)-C(47)-C(48) 164.6(5)
162.1(5)
Pt(2)-C(38)-C(39) 177.0(4)
Pt(2)-C(46)-C(47) 170.8(4)
different donor atoms. Since compound 2 is more stable and is
obtained with a better yield than 1, it has been used as the
starting material in the reactions of the complex anion
[Pt(C∧P)(CtCPh)2]- with Lewis acid species containing transi-
tion metals.
Cu π bonded to the CtC triple bond of two acetylide
groups.30,40,52,59,87-92
Each “Pt(C∧P)(CtCPh)2” fragment contains a Pt atom in a
slightly distorted square planar geometry, with Pt-C,71-76,78
Reactivity of (NBu4)[Pt(C∧P)(CtCPh)2] (2) toward Lewis
Acid Species of M(I) (M ) Cu, Ag, Au, Tl). The reactions of
2 with monovalent metal species such as [Cu(NCMe)4]PF6,
AgClO4, and TlPF6 in a 1:1 molar ratio (Scheme 1c-e) allowed
the compounds [{Pt(C∧P)(CtCPh)2M}2] (M ) Cu (3), Ag (4),
Tl (5)) to be obtained in moderate yields (55-69%) as air- and
temperature-stable solids. However, the reactions of 2 with
[Au(tht)2]ClO4 at different temperatures (-30, 0, 20 °C) render,
in all cases, mixtures of species from which we have not been
able to isolate and characterize any mixed-metal platinum-gold
alkynyl complex.
Pt-P,71-76,78 and Pt-Calkynyl
bond distances
14,21,79-81,48,56,93
similar to those observed in other complexes with the same kinds
of ligands. The alkynyl ligands mostly lie in their corresponding
platinum coordination planes with angles between the CRtCâ
vectors and the perpendicular to the platinum coordination
planes of 89.56° (C(1)-C(2)), 86.38° (C(9)-C(10)), 89.41°
(C(38)-C(39)), and 79.95° (C(46)-C(47)).82 The structural
details concerning the Pt-alkynyl units [Pt-CRtCâ-CPh] are
typical of µ2-η2(σ,π)-alkynyl bridging complexes.48,60,65,70 In
particular, these units deviate from linearity (Table 3), this
distortion being more remarkable at the Câ atom, with the
CRtCâ lengths being longer than those of typical terminal
alkynyl complexes and even somewhat longer than those
reported for other mixed-metal platinum-copper(I) complexes.20
The Pt‚‚‚Cu (2.944(1)-3.179(1) Å) and Cu‚‚‚Cu (3.036(1) Å)
intermetallic distances are long enough to exclude metal-metal
bonds.94
The new compounds [{Pt(C∧P)(CtCPh)2M}2] (M ) Cu (3),
Ag (4), Tl (5)) were characterized by the usual analytical and
spectroscopic means (see the Experimental Section).
The spectroscopic data for 3 and 4 are quite similar, indicating
that they display the same structure, represented in Scheme 1.
The IR spectra of 3 and 4 show νCtC absorptions shifted to
lower wavenumbers with respect to those of the starting material,
2; additionally, the 31P NMR spectra of 3 and 4 show a Pt-P
coupling constant that is more than 400 Hz greater than for 2
(Table 1). According to the literature, these variations in the
IR48,56,65 and NMR65 data with respect to the starting material,
2, suggest the interaction of the M(I) atoms with the π electron
density of the alkynyl ligands.
When we focus on the complex [{Pt(C∧P)(CtCPh)2Tl}2]
(5), it can be seen that its IR and NMR spectroscopic data are
different from those observed for 3 and 4, since the νCtC
absorptions and the Pt-P coupling constant scarcely differ from
those of the starting material, 2 (Table 1). A structure such as
that shown in Scheme 1 is tentatively proposed for 5, taking
into account that PtII-TlI-alkynyl clusters containing donor-
acceptor PtIIfTlI bonds have been described38,39,51 and that the
31P NMR at -80 °C shows one doublet with its corresponding
The structure of 3 has been established by an X-ray diffraction
study (Figure 3, Table 3). It is a tetranuclear complex formed
by two square-planar “Pt(C∧P)(CtCPh)2” fragments held
together by two copper atoms, each one π bonded to two
phenylethynyl groups, one from each fragment, in such a way
that the dihedral angle between the platinum coordination planes
is 56.3(1)°.
195Pt satellites as a consequence of a strong coupling of P to a
203,205
thallium center (400 MHz, CD2Cl2, δ 25.24 ppm, J
)
Tl-P
195
409.9 Hz, J Pt-P ) 2629.3 Hz). The proposed structure explains
(87) Carriedo, G. A.; Miguel, D.; Riera, V.; Solans, X.; Font-Altaba,
M.; Coll, M. J. Organomet. Chem. 1986, 299, C43.
The Cu atoms are bonded to the π electron density of the
CtC triple bond of two alkynyl ligands in a η2 coordination
mode. The Cu atoms can be considered to have a linear
coordination environment, since the C0-Cu-C0′ (C0 and C0′
are the midpoints of the CtC vectors bonded to each Cu) angles
are 160.7(1)° (Cu(1)) and 172.7(1)° (Cu(2)), respectively. The
η2 linkages are somewhat asymmetric, as the Cu-CR lengths
are shorter than the Cu-Câ ones, but all (ca. 2.0 Å) are in the
range of distances observed in other compounds containing
(88) Carriedo, G. A.; Miguel, D.; Riera, V.; Solans, X. J. Chem. Soc.,
Dalton Trans. 1987, 2867.
(89) Bruce, M. I.; Zaitseva, N. N.; Skelton, B. W.; Somers, N.; White,
A. H. Aust. J. Chem. 2003, 56, 509.
(90) Yam, V. W.-W.; Chong, S. H.-F.; Wong, K. M.-C.; Cheung, K.-K.
Chem. Commun. 1999, 1013.
(91) Churchill, M. R.; Bezman, S. A. Inorg. Chem. 1974, 13, 1418.
(92) Mihan, S.; Sunkel, K.; Beck, W. Chem. Eur. J. 1999, 5, 745.
(93) McAdam, C. J.; Blackie, E. J.; Morgan, J. L.; Mole, S. A.; Robinson,
B. H.; Simpson, J. J. Chem. Soc., Dalton Trans. 2001, 2362.
(94) Slater, J. C. J. Chem. Phys. 1964, 41, 3199.

Mono- and Polynuclear Alkynyl Complexes
Organometallics, Vol. 26, No. 7, 2007 1679
the spectroscopic data on the basis of the following consider-
ations: (a) the π coordination of the Pt-alkynyl units of 2 to
an acidic metal (Cu(I) and Ag(I)) causes the νCtC absorption
to shift to lower wavenumbers and the 1JPt-P value to increase
in about 400 Hz and (b) the existence of a PtfM donor-
acceptor bond in complexes containing the metallacycle
1
“Pt(C∧P)” causes a decrease in the value of JPt-P of about
300-700 Hz.71,73-75 If in complex 5 the Pt-alkynyl units are
π coordinated to an acidic metal atom (Tl) and the Pt center is
involved in a PtfTl donor-acceptor bond, the effect of both
facts would compensate one another, making the JPt-P value
not much different from that of the starting material, 2. Also,
the existence of PtfTl donor-acceptor bonds in complex 5
would cause the weakening of the π Tl-alkynyl interactions,
accounting for the small shift of the νCtC absorptions to lower
wavenumbers with respect to 2.
Figure 4. Molecular structure of compound 6 (50% probability
Reactivity of 2 toward the Lewis Acid Species [Pt(C∧P)-
(THF)2]+. Synthesis and Characterization of [{Pt(C∧P)(µ-
CtCPh)}2] (6). The bis(σ-alkynyl) complex (NBu4)[Pt(C∧P)-
(CtCPh)2] (2) reacts with the equimolar amount of the cationic
species [Pt(C∧P)(THF)2](ClO4), which is prepared “in situ”
from [{Pt(C∧P)(µ-Cl)}2]78 and AgClO4 to give the neutral
homodinuclear complex [{Pt(C∧P)(µ-CtCPh)}2] (6) (Scheme
1f). Complex 6 results from an alkynylating process of the
“Pt(C∧P)” fragment and was isolated as an air- and temperature-
stable solid in good yield. It can also be prepared straighfor-
wardly by treating the dinuclear chloro-bridged complex
[{Pt(C∧P)(µ-Cl)}2] with the stoichiometric amount of LiCt
CPh (1:2 molar ratio) in THF at low temperature (Scheme 1g).
This one-step synthetic process of 6 is noteworthy, since
reactions with organolithium compounds are not usually made
in stoichiometric relation to achieve partialy alkylated organo-
metallic compounds. In this case the synthesis of 6 could take
place through two reaction pathways: (a) monoalkynylation to
give the unsaturated fragment “Pt(C∧P)(σ-CtCPh)”, which
dimerizes to give [{Pt(C∧P)(µ-CtCPh)}2] (6) in good yield
(61%), or (b) the initial formation of 2 and subsequent reaction
with the unreacted [{Pt(C∧P)(µ-Cl)}2]. In fact, the reaction of
(NBu4)[Pt(C∧P)(CtCPh)2] (2) with [{Pt(C∧P)(µ-Cl)}2] in a
2:1 molar ratio in THF renders [{Pt(C∧P)(µ-CtCPh)}2] (6),
which was obtained in 78% yield after evaporation to dryness
and addition of methanol to the residue.95
ellipsoids).
Table 4. Selected Bond Distances (Å) and Angles (deg) for
[{Pt(C∧P)(µ-CtCPh)}2] (6)
Pt-C(1)
Pt-C(1′)
Pt-P
2.039(3)
2.368(3)
2.2600(7)
Pt-C(15)
Pt-C(2′)
C(1)-C(2)
2.150(3)
2.311(3)
1.255(4)
C(1)-Pt-P
C0′-Pt-C(1)
97.05(8)
83.1(1)
C(15)-Pt-P
C0′-Pt-C(15)
81.88(8)
97.5(1)
and Pt-C(2′) lengths are equal within experimental error,
indicating the symmetry of the platinum acetylide π-linkages.
Symmetrical65 and asymmetrical70 η2-acetylide-platinum link-
ages have been described previously. The structural details
concerning the Pt-alkynyl units [Pt-CRtCâ-CPh] are typical
of µ2-η2(σ,π)-alkynyl bridging complexes.48,60,65,70 In particular,
these units deviate from linearity, this distortion being more
pronounced at the Câ atom, and the CRtCâ lengths are slightly
elongated with respect to terminal alkynyl complexes.
Structural details concerning the “Pt(C∧P)” metallacycle are
similar to those observed in other complexes containing it.71-76,78
The best plane defined by the metallacycle atoms (Pt, P, C(9),
C(10), C(15)) and the platinum coordination plane, defined by
Pt, C(1), P, C(15), and C0 (C0 being the midpoint of the CtC
vector π-bonded), are almost coplanar, the dihedral angle being
19.0(1)°.82 The intermetallic distance, 3.446(1) Å, is long enough
to exclude any Pt-Pt bonding interaction.
Compound 6 was fully characterized by the usual analytical
and spectroscopic means and also by X-ray crystallography. Its
X-ray structure (Figure 4, Table 4) shows that it is a double
alkynyl bridged dinuclear complex formed by two identical
“Pt(CH2C6H4P(o-tolyl)2)(µ-CtCPh)” fragments held together
by the interaction of the Pt atom of one fragment with the π
electron density of the alkynyl ligand from the other. Each
platinum center shows a distorted-square-planar coordination
environment formed by the phosphorus and carbon donor atoms
of the C∧P ligand, the C of the σ-bonded alkynyl ligand, and
C0 (C0 being the midpoint of the CtC vector π-bonded), since
the angles between cis ligands deviate notably from 90°. The
alkynyl ligands adopt the bonding pattern depicted in G in
Figure 1, each one being trans with respect to the σ-C atom of
the C∧P. The central C4Pt2 core is not planar, and the best least-
squares planes defined for Pt, C(1′), C(2′), Pt′ and Pt, C(1),
C(2), Pt′ form a dihedral angle of 131.8(1)°. Similar nonplanar
structures have been found previously in [C6F5)2Pt(µ-Ct
CPh)2Pt(C6F5)2]2- 65 and [Ir(COD)(CtCPh)]2.96 The Pt-C(1′)
The IR spectrum of 6 shows one absorption in the CtC bond
region that is perceptibly shifted to lower wavenumbers
compared to those observed in complexes with terminal
σ-acetylide ligand (complexes 1 and 2) or even µ2-η2-σ,π-
acetylide ligands (complexes 3 and 4) attributable to the
“Pt(µ-CtC)2Pt” moiety.65,70 The 1H NMR and 31P NMR spectra
show the expected signals for a half of the molecule in
agreement with its symmetry; however, while the 1H NMR does
not show relevant changes with respect to that of compound 2,
the 31P NMR spectrum does, since it strongly depends on the
alkynyl bond pattern. Thus, the trans disposition of a π-alkynyl
ligand with the P atom causes the 31P signal to be shifted to
higher field by about 7 ppm with respect to complex 2 and the
JPt-P value to increase by almost 1600 Hz (Table 1), in
agreement with the smaller trans influence of the π-alkynyl with
respect to the σ-alkynyl ligand.
The spectroscopic and X-ray data indicate that the isomer
with a trans disposition of the σ-C bonds around the platinum
center is the only one obtained by each one of the two synthetic
methods described here. The treatment of [{Pt(C∧P)(µ-Cl)}2]
with LiCtCPh thus allows not only the monoalkynylation of
the platinum fragment “Pt(C∧P)” but also the selectivity of it,
(95) The reaction pathway (b) was suggested by one of the reviewers
and afterwards was confirmed experimentally.
(96) Mu¨ller, J.; Tschampel, M.; Pickardt, J. J. Organomet. Chem. 1988,
355, 513.

1680 Organometallics, Vol. 26, No. 7, 2007
Casas et al.
Scheme 2
affording the unit trans-“Pt(C∧P)(σ-CtCPh)”, which dimerizes
to [{Pt(C∧P)(µ-CtCPh)}2] (6). The high stability of 6 is also
evident, considering that it precipitates “in situ” when solutions
of 1 are stirred for 1 h or more.
Reactivity of [{Pt(C∧P)(µ-CtCPh)}2] (6) toward Mono-
dentate Ligands. Complex 6 reacts with several neutral
monodentate ligands such as CO, py, tht, and PPh3 in a 1:2
molar ratio (see the Experimental Section) to give the neutral
mononuclear complexes [Pt(C∧P)(CtCPh)L] (L ) CO (7), py
(8), tht (9), PPh3 (10)) as pure compounds (Scheme 1h,i).
Complexes 7-10 were characterized by common analytical and
spectroscopic means (see the Experimental Section). All of them
are neutral and exhibit one IR absorption of medium intensity
close to 2100 cm-1 assignable to the νCtC absorption of a
terminal σ-alkynyl group.14,16,21 For complex 7, the presence
of a terminal CO coordinated to platinum is reflected by an
absorption at 2079 cm-1 assignable to ν(CO). Similar values
have been reported in carbonyl complexes with the CO trans
to a σ-C donor ligand (νCO: 2086 cm-1, [Pt{C6H3(CH2NMe2)2-
o,o′}(CO)];97 2079 cm-1, [Pt(Et)(CO)(PEt3)2]+;98 2078-2092
cm-1, [(CO)(C6F5)2Pt(µ-η2-CtCR)Pt(CtCR)(PR3)2]99). The 31
P
NMR spectra of complexes 7-9 show one singlet with the
corresponding 195Pt satellites and the typical signals of an AB
system for complex 10. In agreement with their stoichiometry,
the 13C NMR spectra show the CR and Câ resonances of only
one alkynyl ligand, in addition to the signals due to the other
ligands. For these mononuclear compounds two isomers are
possible, depending on the trans or cis disposition of the two
σ-C-donor ligands [C(C∧P), σ-CtCPh] around the Pt center,
depicted as A and B in Scheme 2. The trans isomer, A, results
from complex 6 if the substitution of the π-acetylide by the
neutral ligand, L, in the coordination sphere of each Pt center
proceeds with stereoretention. If not, the cis isomer, B (Scheme
2), is formed. The 31P NMR signals strongly depend on the
ligand trans to the phosphorus atom. In complex 10, the
2
magnitude of JP-P (433 Hz) is consistent with the trans
disposition of the two P atoms (A).100 Considering the general
observation that a smaller JPt-P value corresponds to a larger
trans influence of the ligand trans to P, if all the complexes
(7-10) exhibited the same structure (A), the expected values
of JPt-P for complexes 7-9 would be larger than for complex
10. As complexes 7-9 show smaller Pt-P coupling than 10,
the structure depicted as B seems to be more plausible for them.
This assumption is supported by several facts. (a) The JPt-P
values in complexes 8 (L ) py) and 9 (L ) tht) are similar to
that observed in complex 2, in which the P is trans to a σ-alkynyl
group, and smaller than that expected for the A isomer.101 (b)
The observed P-C coupling for the CR and Câ atoms of the
alkynyl group (see 13C NMR data in the Experimental Section)
indicates the trans disposition of this ligand with respect to P;
this coupling is not observed for complex 10 (L ) PPh3). (c)
The values of δCO and JPt-C observed in the 13C NMR spectrum
of 7 indicate the trans disposition of CO to an alkyl ligand.102
The single-crystal X-ray diffraction study carried out on complex
7 (Figure 5, Table 5) confirmed the proposed structure for these
complexes (7-9).
Assuming the B structure for complexes 7-9 (L ) CO, py,
tht), when the values of JPt-CH in complexes 2 and 7-9 are
2
compared, it can be seen that they decrease in the order L )
py (8; 637.3 Hz) > tht (9; 630.6 Hz) > CO (7; 537.4 Hz) >
σ-CCPh (2; 458.8 Hz). Thus, the trans influence should increase
as follows: σ-CtCPh > CO > tht > py.
(97) Grove, D.; van Koten, G.; Louwen, J. N.; Noltes, J. G.; Spek, A.
L.; Ubbels, H. J. C. J. Am. Chem. Soc. 1982, 104, 6609.
(98) Clark, H. C.; Jablonski, C. R.; Wong, C. S. Inorg. Chem. 1975, 14,
1332.
(99) Berenguer, J. R.; Fornie´s, J.; Lalinde, E.; Mart´ınez, F.; Urriolabeitia,
E.; Welch, A. J. J. Chem. Soc., Dalton Trans. 1994, 1291.
(100) Pregosin, P. S.; Kunz, R. W. 31P and 13C NMR Transition Metal
Phosphine Complexes; Springer-Verlag: Berlin, 1979.
(101) Diez, A.; Fornie´s, J.; Garc´ıa, A.; Lalinde, E.; Moreno, M. T. Inorg.
Chem. 2005, 44, 2443.
(102) Mann, B. E.; Taylor, B. F. 13C NMR Data for Organometallic
Compounds; Academic Press: London, 1981.
Figure 5. Molecular structure of compound 7.

Mono- and Polynuclear Alkynyl Complexes
Organometallics, Vol. 26, No. 7, 2007 1681
Table 5. Selected Bond Distances (Å) and Angles (deg) for
lengths are in the range of those found in other four-coordinate
Pt(II) carbonyl complexes.103-110 No lengthening of the CO bond
as a consequence of the significant π back-donation to the
terminal CO ligand, inferred from the low νCO value, is
observed.
[Pt(C∧P)(CtCPh)(CO)]‚Me2CO (7‚Me2CO)
Pt-C(9)
Pt-C(16)
O(1)-C(9)
1.899(5)
2.096(4)
1.130(6)
Pt-C(1)
Pt-P
C(1)-C(2)
2.020(4)
2.2960(10)
1.192(6)
C(9)-Pt-C(1)
C(1)-Pt-C(16)
C(1)-Pt-P
87.39(18)
89.10(17)
171.53(12)
172.0(4)
C(9)-Pt-C(16)
C(9)-Pt-P
176.37(17)
100.97(14)
82.51(12)
176.2(4)
Reactivity of (NBu4)[Pt(C∧P)(CtCPh)2] (2) toward
[M(C6F5)2(THF)2] (M ) Pd, Pt). The reaction of equimolar
amounts of the neutral complexes [M(C6F5)2(THF)2] (M ) Pd,
Pt) and the bis(σ-alkynyl) complex (NBu4)[Pt(C∧P)(CtCPh)2]
(2) at room temperature gave the analytically pure compounds
(NBu4)[Pt(C∧P)(CtCPh)2M(C6F5)2] (M ) Pd (11), Pt (12))
in moderate to good yields as air- and temperature-stable solids
(Scheme 1j,k). In a solution of CH2Cl2, compound 11 decom-
poses after 1 h, but 12 is stable for a longer time. The two
compounds were characterized by elemental analysis, conduc-
tivity measurements, and IR and NMR (1H, 19F, 31P) spectros-
copy. Conductivity measurements in acetone are similar to those
for compound 2 and confirm their behavior as 1:1 electrolytes.77
Significant structural information can be extracted from the
IR and 31P NMR spectra of these complexes. Two absorptions
assignable to the X-sensitive vibration modes of the C6F5 groups
are observed in the IR spectra, indicating the cis arrangement
of the ”M(C6F5)2” moiety111 in both 11 and 12. The IR spectra
of compounds 11 and 12 also show νCtC absorptions, but at
quite different wavenumbers. Complex 11 shows one absorption
at 2033 cm-1, at wavenumbers similar to those of complexes
C(16)-Pt-P
C(2)-C(1)-Pt
O(1)-C(9)-Pt
C(1)-C(2)-C(3)
174.4(4)
Several spectroscopic facts concerning complex 7 are note-
worthy. (a) The low value observed for the νCO absorption (2079
cm-1) when compared with those of other neutral platinum(II)
carbonyl complexes103-110 suggests that the metal center in 7
is appreciably electron rich and that there is significant π back-
donation to the terminal CO ligand. (b) The high wavenumbers
for the νCtC absorption (2127 cm-1) compared with those in
the analogous complexes 8 and 9 and the notable shift of the
CR resonance (101.85 ppm) to a higher field with respect to
those in the starting complex, 2 (120.33 ppm, CR trans to P)
indicate the scarce π back-bonding from Pt to the alkynyl ligand
(in the remaining mononuclear complexes described in this
paper, the CR resonance appears at a lower field than the Câ
resonance, but not in complex 7), this spectroscopic feature
being commonly observed for the compounds cis-[Pt(C6F5)2-
(CtCR)2]2- 57
[{Pt(C6F5)2(µ-CtCtBu)2}{Cu(bipy)}2].30 (c) The value of
JPt-P(C is small in comparison with those in the analogous
,
[PtCu2(C6F5)2(CtCR)2(acetone)]2,30 and cis-
3-5, while compound 12 shows one absorption at 1957 cm-1
,
∧
comparable with that in complex 6, which contains a “Pt(µ-
CtCPh)2Pt” moiety. The 31P NMR spectra of 11 and 12 show
the expected singlet with the corresponding 195Pt satellites, being
JPt-P ) 3013 Hz for complex 11, similar to the values for
complexes 3 and 4, and 4223 Hz for complex 12, similar to the
value for complex 6 (Table 1). In keeping with the above
spectroscopic data, it seems sensible to assign to 11 and 12 the
molecular structures depicted in Scheme 1, with the bonding
patterns for the acetylide groups being A and G (Figure 1),
respectively.
In agreement with these proposed structures, the 19F NMR
spectra of 11 and 12 at room temperature exhibit two sets of
signals (2:1:2, typical of a AA′MXX′ system in which the two
ortho fluorine atoms, as well as the meta atoms, are isochronous
or become equivalent) in a 1:1 ratio, indicating the inequivalence
of the two C6F5 groups.
The reaction of complex 11 with PPh3 (Scheme 3) in a 1:2
molar ratio was carried out in CD2Cl2 and monitored by NMR.
The 31P NMR spectra, registered at several interval times, show
the presence of [Pd(C6F5)2(PPh3)2]112 and (NBu4)[Pt(C∧P)(Ct
CPh)2] (2) as the major products and remain invariable even
24 h later. The reaction of compound 12 with PPh3 (Scheme 3)
in a 1:2 molar ratio gave [Pt(C∧P)(CtCPh)(PPh3)] (10) and
(NBu4)[Pt(C6F5)2(CtCPh)(PPh3)] (13). The two compounds
could be easily separated, because of their very different
solubilities in methanol (see the Experimental Section).
Cis/Trans Disposition of the σ-C Bonds in Complexes
6-10 and 12. Two isomers are possible for each one of
complexes 6-10 and 12, depending on the cis or trans
disposition of the two σ-C-donor ligands (C(C∧P), σ-CtCPh)
around the Pt center (Scheme 2 and Chart 1). Compounds 6
and 12 are each formed by selective transfer of an alkynyl group
from complex 2 to the cationic and neutral Pt(II) complexes
[Pt(C∧P)(THF)2]+ and cis-[Pt(C6F5)2(THF)2]. Complex 6 is also
P)
complexes 8 and 9. All of these spectroscopic facts can be
explained by considering that in complex 7, the richer π-acceptor
character of CO, with respect to σ-alkynyl (2), pyridine (8), or
tht (9), is responsible for the scarce π back-bonding to the
alkynyl and PC∧P ligands.
The X-ray structure of compound 7 (Figure 5) shows that it
is a mononuclear complex in which the center of Pt(II) shows
a distorted-square-planar environment mainly due to the small
bite angle of the C∧P ligand (82.5(1)°). The trans disposition
of the σ-alkynyl and P ligands unambiguously indicates that
the substitution of π-alkynyl by CO in complex 6 takes place
with isomerization. The Pt-P,71-76,78 Pt-CC∧P
,
and
71-76,78
14,15,79-81
Pt-Calkynyl
distances are all in the range of those
observed in complexes of Pt(II) with the same kinds of ligands.
While the Pt-P and Pt-Calkynyl distances are longer with respect
to those in complex 2, the Pt-CC∧P distance remains invariable.
This fact seems to be logical, taking into account that the neutral
nature of complex 7 and the presence of a good π acceptor
ligand (CO) will reduce the π back-bonding from Pt(II) to the
phosphine and the alkynyl ligand, in agreement with the
observed spectroscopic facts for it. The Pt-CCO and C-O
(103) Bagnoli, F.; Belli Dell’Amico, D.; Calderazzo, F.; Englert, U.;
Marchetti, F.; Herberich, G. E.; Pasqualetti, N.; Ramello, S. J. Chem. Soc.,
Dalton Trans. 1996, 4317.
(104) Andreini, B. P.; Belli Dell’Amico, D.; Calderazzo, F.; Venturi,
M. G.; Pelizzi, G.; Segre, A. J. Organomet. Chem. 1988, 354, 357.
(105) von Ahsen, B.; Wartchow, R.; Willner, H.; Jonas, V.; Aubke, F.
Inorg. Chem. 2000, 39, 4424.
(106) Willner, H.; Bodenbinder, M.; Bro¨chler, R.; Hwang, G.; Rettig,
S. J.; Trotter, J.; von Ahsen, B.; Westphal, U.; Jonas, V.; Thiel, W.; Aubke,
F. J. Am. Chem. Soc. 2001, 123, 588 and references therein.
(107) Bagnoli, F.; Belli Dell’Amico, D.; Calderazzo, F.; Englert, U.;
Marchetti, F.; Merigo, A.; Ramello, S. J. Organomet. Chem. 2001, 622,
180.
(108) Lin, G.; Jones, N. D.; Gossage, R. A.; McDonald, R.; Cavell, R.
G. Angew. Chem., Int. Ed. 2003, 42, 4054.
(109) Berenguer, J. R.; Fornie´s, J.; Mart´ın, L. F.; Mart´ın, A.; Menjo´n,
B. Inorg. Chem. 2005, 44, 7265.
(110) Casas, J. M.; Fornie´s, J.; Mart´ınez, F.; Rueda, A. J.; Toma´s, M.
Inorg. Chem. 1999, 38, 1529.
(111) Uso´n, R.; Fornie´s, J. AdV. Organomet. Chem. 1988, 28, 219.
(112) Uso´n, R.; Fornie´s, J.; Espinet, P.; Mart´ınez, F.; Toma´s, M. J. Chem.
Soc., Dalton Trans. 1981, 463.

1682 Organometallics, Vol. 26, No. 7, 2007
Casas et al.
Scheme 3
has been assumed to be related to the trans influence in such a
way that two ligands with large trans influence will suffer a
great transphobia. However, the steric requirements of the
ligands involved can also play a significant role in determining
the geometries of these complexes.116,117
Recent studies on the factors that promote the stability of
cis- or trans-diarylplatinum(II) complexes concluded that
“complexes cis-[Pt(aryl)2L2] are more stable than the trans
isomers if L ligands are N, O, or S donor ligands because
T[Aryl/Aryl]>> T[Aryl/L(N,O,S)] unless the aryl or L ligands
are highly voluminous. However, because T[Aryl/Aryl] is similar
to T[Aryl/L(C,P)], the complexes trans-[Pt(aryl)2{L(C,P)}2] can
be more stable than the cis isomers if interligand repulsions
are important, in such a way that the cis isomers can isomerize
to their trans ones by heating if the temperature required is below
their decomposition temperatures and the ligands are sufficiently
bulky.”117
Taking into account these assumptions, from the observed
J
Pt-P(C∧P) and JPt-C(alkynyl) values in complexes 2, 6, 10, and 12
the trans influence order must be σ-CtC > PPh3> π-CtC and
the trans influence of σ-C(C∧P) must be greater than that of
P(C∧P); then, T[C(σ-CtC)/C(C∧P)] is expected to be greater
than T[C(σ-CtC)/P(C∧P)] and T[C(C∧P)/C(σ-CtC)] >
T[C(C∧P)/L(PPh3)] > T[C(C∧P)/L(π-CtC)]. Thus, the trans
disposition of the σ-C-donor ligands (C(C∧P), σ-CtC) around
the Pt center observed in complexes 6 and 12, despite the
expected electronic preferences, can be attributed to the steric
hindrance between P(o-tolyl)2 and the Ph group of σ-CtCPh
in the cis isomer. The same applies to the other stable trans
complex [Pt(C∧P)(CtCPh)PPh3] (10), which is formed instead
of the cis isomer, probably because of the crowding associated
with the cis disposition of P(o-tolyl)2 and PPh3.
Chart 1
However, the substitution reactions at room temperature on
complex 6 with the nonbulky ligands CO, py, and tht do not
proceed with stereoretention, giving rise to the complexes cis-
[Pt(C∧P)(CtCPh)L] (L ) CO (7), py (8), tht (9)), in agreement
with T[C(C∧P)/C(σ-CtC)] > T[C(C∧P)/C(CO)] > T[C(C∧P)/
L(py,tht)]. This order in the transphobia (T) of pairs of trans
ligands is in agreement with the trans influence order deduced
from the JPt-C(C
> CO > py ≈ tht.
∧
values in complexes 2 and 7-9: σ-CtC
P)
Summary
This paper describes the synthesis of the monoanionic bis-
(σ-alkynyl) complex [Pt(C∧P)(CtCPh)2]-, that has been
isolated as its Li+ (1) and (NBu4) (2) salts, and its reactivity
toward Lewis acid species of transition metals, M (M ) Cu(I),
Ag(I), Au(I), Tl(I), Pd(II), Pt(II)). These reactions give rise, in
many cases, to heteropolynuclear complexes and exhibit dif-
ferent bonding patterns for the bridging alkynyl ligands depend-
ing on M.
The reactions with [Cu(NCMe)4]PF6 and AgClO4 show the
preference of the MI centers (M ) Cu, Ag) for the electron-
rich alkynyl units and give tetranuclear compounds (Pt2M2, 3
and 4) of type C (Figure 1). However, the reaction with TlPF6
rendered a new Pt-Tl complex (5) likely to contain PtfTl
dative bonds, which shows the higher affinity of thallium for
the electron density of platinum(II). In agreement with the scarce
number of mixed platinum-gold alkynyl compounds, the
reactions of compound 2 with Au(I) species proceed with
obtained by selective monoalkynylation of a “Pt(C∧P)” fragment
with LiCtCPh. Complexes 7-10 are obtained by reaction of
6 with 2 equiv of L (L ) CO, py, tht, PPh3) (Scheme 1). In all
of these cases, only one of the two possible isomers is formed
selectively (Schemes 2 and 3). In an attempt to explain the
factors that influence the formation of one isomer instead of
the other, we have used the term transphobia (T) of pairs of
trans ligands, which has been accepted by many authors to
explain the geometries of stable square-planar complexes of d8
transition metals.113-117 The degree of T of pairs of trans ligands
(113) Vicente, J.; Arcas, A.; Bautista, D.; Jones, P. G. Organometallics
1997, 16, 2127.
(114) Vicente, J.; Abad, J. A.; Frankland, A. D.; Ram´ırez de Arellano,
M. C. Chem. Eur. J. 1999, 5, 3066.
(115) Vicente, J.; Abad, J. A.; Herna´ndez-Mata, F. S.; Jones, P. G. J.
Am. Chem. Soc. 2002, 124, 3848.
(116) Vicente, J.; Abad, J. A.; Mart´ınez-Vicente, E.; Jones, P. G.
Organometallics 2002, 21, 4454.
(117) Vicente, J.; Arcas, A.; Ga´lvez-Lo´pez, M. D.; Jones, P. G.
Organometallics 2006, 25, 4247.

Mono- and Polynuclear Alkynyl Complexes
Organometallics, Vol. 26, No. 7, 2007 1683
[{Pt(C∧P)(µ-Cl)}2] (0.667 g, 0.62 mmol) was added and allowed
to react at room temperature for 15 h. The resulting mixture was
air-evaporated to dryness. CHCl3 (3 × 30 mL) was added to the
residue at 0 °C, the mixture was filtered through Celite, and the
resulting solution was evaporated to dryness. The oily residue was
treated with iPrOH (15 mL) and n-hexane (30 mL) and the resulting
solution evaporated to dryness. Addition of n-hexane gave 1 as a
brown solid. Yield: 0.385 g, 49%. Anal. Calcd for C37H30LiPPt:
C, 62.86; H, 4.24. Found: C, 62.60; H, 4.40. Negative FAB-MS
(m/z (%)): 700 (90) [M - Li] -. IR (Nujol, cm-1): ν 2078 (m,
CtC). 1H NMR (300 MHz, CD2Cl2, 293 K): δ 6.7-7.7 (m, 22H,
alkylation of the gold center, and no mixed platinum-gold
alkynyl compounds could be isolated.
In addition, the reactivity of (NBu4)[Pt(C∧P)(CtCPh)2] (2)
toward the neutral cis-[Pd(C6F5)2(THF)2] renders the compound
(NBu4)[Pt(C∧P)(CtCPh)2Pd(C6F5)2] (11), with a bonding pat-
tern of type A (Figure 1), which has a very limited stability in
solution. However, the reactions with the cationic and neutral
Pt(II) complexes [Pt(C∧P)(THF)2]+ and cis-[Pt(C6F5)2(THF)2]
render compounds 6 and 12 of type G (Figure 1) as a
consequence of an alkynylating process. These reactions proceed
selectively to give only one of the two possible isomers for
compounds 6 and 12. These compounds are highly stable, even
in solution. The cleavage of the bridging system “Pt2(µ-Ct
CPh)2” can be achieved by some neutral ligands, L. Thus, the
reactions of 6 with L at room temperature in a 1:2 molar ratio
give the mono(σ-alkynyl) complexes [Pt(C∧P)(CtCPh)L] (L
) CO (7), py (8), tht (9), PPh3 (10)). When L ) PPh3, the
substitution reaction takes place with stereoretention, but not
when L ) CO, py, and tht.
Two isomers are possible for each one of complexes 6-10
and 12, depending on the cis or trans disposition of the two
σ-C-donor ligands (C(C∧P), σ-CtCPh) around the Pt center,
but only one has been obtained in each case. This seems to
depend as much on the transphobia of pairs of trans ligands as
on the steric requirements of cis ligands.
Thus, the cis isomer should be observed on the basis of
electronic preferences (T[C(σ-CtC)/C(C∧P)] g T[C(σ-CtC)/
P(C∧P)]; T[C(C∧P)/C(σ-CtC)] > T[C(C∧P)/L(PPh3)] >
T[C(C∧P)/L(π-CtC)]; T[C(C∧P)/C(σ-CtC)] > T[C(C∧P)/
C(CO)] > T[C(C∧P)/L(py, tht)). However, the trans disposition
of the σ-C-donor ligands (C(C∧P), σ-CtC) around the Pt center
is observed in complexes 6, 12, and 10, which can be attributed
to the steric hindrance between P(o-tolyl)2 and the Ph group of
σ-CtCPh in the cis isomer (complexes 6 and 12) or P(o-tolyl)2
and PPh3 in complex 10.
2
Ph groups), 3.1 (s, 2H, CH2, JPt-H ) 63.9 Hz), 2.64 (s, 6H, Me).
1
31P NMR (300 MHz, CD2Cl2, 293 K, ppm): δ 32.0 (s, JPt-P
)
2746 Hz). 7Li NMR (400 MHz, CD2Cl2, 293 K, ppm): δ 0.43 (s).
ΛM ) 32.31 Ω-1 cm2 mol-1 (solution 2.5 × 10-4 M in acetone).
NBu4[Pt(C∧P)(CtCPh)2] (2). A solution of nBuLi (5.0 mmol)
in THF (15 mL) was added to a solution of HCtCPh (0.566 mL,
5.0 mmol) in THF at low temperature (ca. -20 °C) under an
argon atmosphere. The mixture was stirred for 15 min, and then
[{Pt(C∧P)(µ-Cl)}2] (1.067 g, 1.00 mmol) was added and allowed
to react at room temperature for 15 h. The resulting mixture was
air-evaporated to dryness. CHCl3 (3 × 30 mL) was added to the
residue at 0 °C, the mixture was filtered through Celite, and the
i
solution was evaporated to dryness. PrOH (50 mL) and NBu4Br
(1.210 g, 3.75 mmol) were added to the residue to give a light
brown solid of 2, which was filtered and washed with n-hexane
(10 mL) and Et2O (10 mL). Yield: 1.49 g, 79%. Anal. Calcd for
C53H66NPPt: C, 67.52; H, 7.06; N, 1.48. Found: C, 67.48; H, 6.94;
N, 1.60. Negative FAB-MS (m/z (%)): 700 (100) [M - NBu4]-.
1
IR (Nujol, cm-1): ν 2098 (m, CtC), 2081(m, CtC). H NMR
(300 MHz, CD2Cl2, 293 K, ppm): δ 6.7-7.5 (m, 22 H, Ph groups),
3.09 (m, 8 H, CH2, NBu4+), 2.96 (s, 2 H, CH2, 2JPt-H ) 64.8 Hz),
2.75 (s, 6 H, CH3), 1.43 (m, 8 H, CH2, NBu4+), 1.26 (m, 8 H,
CH2, NBu4+), 0.83 (t, JH-H ) 6.9 Hz, 12 H, CH3, NBu4+). 13C
3
NMR (400 MHz, CD2Cl2, 293 K, ppm): δ 165-123 (CPh, CRtC
trans to C), 120.33 (d, 2JP-C ) 160.0 Hz, JPt-C ) 1260.0 Hz, CRtC
trans to P), 107.86 (s, 2JPt-C ) 231.8 Hz, CâtC trans to C), 105.69
When L ligands are the nonbulky CO, py, and tht, the
expected more stable cis isomers were obtained.
3
2
(d, JP-C ) 39.6 Hz, JPt-C ) 354.0 Hz CâtC trans to P), 23.40
(s, JPt-C ) 458.8 Hz, CH2), 23.67 (s, broad, Me). 31P NMR (300
MHz, CD2Cl2, 293 K, ppm): δ 31.8 (s, JPt-P) 2603 Hz). ΛM
45.53 Ω-1 cm2 mol-1 (solution 5.1 × 10-4 M in acetone).
1
)
Experimental Section
[{Pt(C∧P)(CtCPh)2Cu}2] (3). 2 (0.208 g, 0.22 mmol) was
added to a colorless solution of [Cu(NCMe)4]PF6 (0.082 g, 0.22
mmol) in CH2Cl2 (10 mL) under an argon atmosphere in a ice bath,
giving rise to a dark orange solution. The mixture was allowed to
react for 30 min, and then the solvent was evaporated to dryness.
Addition of MeOH (20 mL) to the residue gave 3, which was
filtered, washed with MeOH (10 mL), and air-dried. Yield: 0.117
g, 69%. Anal. Calcd for C74H60Cu2P2Pt2: C, 58.17; H, 3.92.
Found: C, 57.86; H, 3.55. IR (Nujol, cm-1): ν 2007 (w, CtC),
General Procedures and Materials. Elemental analyses were
carried out in a Perkin-Elmer 240-B microanalyzer. IR spectra were
recorded on a Perkin-Elmer 599 spectrophotometer (Nujol mulls
between polyethylene plates in the range 350-4000 cm-1). NMR
spectra were recorded on Varian Unity-300 and Bruker 400
spectrometers by using the standard references: TMS for 1H,
7
H3PO4 for 31P, and LiCl in H2O for Li. All of the 31P and 13C
NMR esperiments were proton-decoupled. Mass spectral analyses
were performed with a VG Austospec instrument. THT and
phenylacetylene were purchased from Merck, TlPF6 from Strem
Chemicals, and PPh3 from Fluka. [Cu(MeCN)4]PF6,118 PPN-
[Au(acac)2],119 [Au(tht)2]ClO4,120 AgClO4,121 [{Pt(C∧P)(µ-Cl)}2],78
[cis-Pd(C6F5)2(THF)2],122 and [cis-Pt(C6F5)2(THF)2],122 were pre-
pared as described elsewhere.
Li[Pt(C∧P)(CtCPh)2] (1). A solution of nBuLi (2,5 mmol) in
THF (15 mL) was added to a solution of HCtCPh (0.283 mL,
2.50 mmol) in THF at low temperature (ca -20 °C) under an
argon atmosphere. The mixture was stirred for 15 min, and then
1
1971 (w, CtC). H NMR (300 MHz, CD2Cl2, 293 K, ppm): δ
2
6.7-7.6 (m, 44 H, Ph groups), 3.28 (s, 4 H, CH2, JPt-H ) 66.0
Hz), 2.45 (s, 12 H, Me). 31P NMR (300 MHz, CD2Cl2, 293 K,
1
ppm): δ 30.2 (s, JPt-P) 3056 Hz).
[{Pt(C∧P)(CtCPh)2Ag}2] (4). A solution of 2 (0.2055 g,
0.2179 mmol) in CH2Cl2 (15 mL) was added to a colorless solution
of AgClO4 (0.0452 g, 0.2180 mmol) in diethyl ether (8 mL) at
room temperature, giving rise to a dark orange solution. The mixture
was allowed to react for 2 h in the dark; then the solvent was
evaporated to dryness and MeOH (20 mL) was added to the residue.
The solid was recrystallized from diethyl ether/methanol to give 4
as an orange solid. Yield: 0.1091, 62%. Anal. Calcd for Ag2C74H60P2-
Pt2: C, 54.96; H, 3.71. Found: C, 55.08; H, 3.87. IR (Nujol, cm-1):
ν 2019 (w, CtC). 1H NMR (300 MHz, CD2Cl2, 293 K, ppm): δ
(118) Kubas, G. J. Inorg. Synth. 1990, 19, 90.
(119) Vicente, J.; Chicote, M. T. Inorg. Synth. 1998, 32, 175.
(120) Uso´n, R.; Laguna, A.; Laguna, M.; Jime´nez, J.; Go´mez, M. P.;
Sainz, A.; Jones, P. G. J. Chem. Soc., Dalton Trans. 1990, 3457.
(121) Brauer, G. Handbuch der Pra¨paratiVen Anorganischen Chemie,
3rd ed.; Ferdinand Enke Verlag: Stuttgart, Germany, 1978; p 997.
(122) Uso´n, R.; Fornie´s, J.; Toma´s, M.; Menjo´n, B. Organometallics
1985, 4, 1912.
2
6.7-7.6 (m, 44 H, Ph groups), 3.33 (s, 4 H, CH2, JPt-H ) 65.0
Hz), 2.54 (s, 12 H, Me). 31P NMR (400 MHz, CD2Cl2, 293 K,
1
ppm): δ 29.2 (s, JPt-P ) 3015 Hz).

1684 Organometallics, Vol. 26, No. 7, 2007
Casas et al.
[{Pt(C∧P)(CtCPh)2Tl}2] (5). A solution of TlPF6 (0.093 g,
0.266 mmol) in MeOH (10 mL) was added to a solution of 2 (0.250
g, 0.265 mmol) in CH2Cl2 (20 mL) and the mixture stirred for 1 h
in a ice bath. Then, the solvent was evaporated to dryness and
acetone (15 mL) was added to the residue. The resulting solution
was evaporated to dryness and MeOH (30 mL) added to the resi-
due, to give a solid of 5, which was washed with Et2O (30 mL)
and MeOH (15 mL), Yield: 0,1310 g, 55%. Anal. Calcd for
C74H60P2Pt2Tl2: C, 49.11; H, 3.31. Found: C, 49.02; H, 3.55. IR
(Nujol, cm-1): ν 2088 (m, CtC), 2059 (m, CtC). 1H NMR (300
MHz, CD2Cl2, 293 K, ppm): δ 6.6-7.6 (m, 44 H, Ph groups),
3.21 (s, 4 H, CH2, 2JPt-H ) 59.4 Hz), 2.38 (s, 6 H, Me). 31P NMR
the residue, giving a yellow solid of 9. Yield: 0.1442 g, 70%. Anal.
Calcd for C33H33SPPt: C, 57.66; H, 4.80; S, 4.66. Found: C, 57.44;
1
H, 4.90; S, 4.25. IR (Nujol, cm-1): ν 2103 (w, CtC). H NMR
(300 MHz, CDCl3, 293 K, ppm): δ 6.8-7.6 (m, 17 H, Ph groups),
3.64 (s, 2 H, CH2, 2JPt-H ) 84.0 Hz), 3.31 (m, 4 H, tht), 2.56 (s, 6
H, Me), 2.07 (m, 4 H, tht). 13C NMR (400 MHz, CD2Cl2, 293 K,
2
ppm): δ 160-125 (CPh), 117.16 (d, JP-C ) 179.3 Hz, CRtC),
3
103.53 (d, JP-C ) 32.3 Hz, CtCâ), 38.07 (s, tht), 30.44 (s, tht),
22.95 (s, Me), 17.32 (s, JPt-C ) 630.6 Hz, CH2). 31P NMR (300
1
MHz, CDCl3, 293 K, ppm): δ 31.9 (s, JPt-P ) 2696 Hz).
[Pt(C∧P)(CtCPh)(PPh3)] (10). PPh3 (0.070 g, 0.267 mmol)
was added to a stirred solution of 6 (0.16 g, 0.267 mmol) in
CH2Cl2 (15 mL) and the mixture allowed to react for 1 h. The
resulting solution was evaporated to dryness and MeOH (20 mL)
added to the residue, giving a white solid of 10, which was filtered
and washed with Et2O (30 mL). Yield: 0.095 g, 41%. Anal. Calcd
for C47H40P2Pt: C, 65.52; H, 4.64. Found: C, 65.37; H, 4.38. IR
1
(300 MHz, CD2Cl2, 293 K, ppm): δ 29.3 (s, JPt-P ) 2681 Hz).
[{Pt(C∧P)(µ-CtCPh)}2] (6). Method A. A solution of
[Pt(C∧P)(THF)2]ClO4 (0.513 mmol), preparated “in situ” from
[{Pt(C∧P)(µ-Cl)}2] (0.2736 g, 0.256 mmol) and AgClO4 (0.1060
g, 0.5113 mmol) in THF, was evaporated to dryness and the residue
treated with CHCl3 (20 mL). Compound 2 (0.4834 g, 0.5126 mmol)
was added to the resulting solution. After 2 h of stirring at room
temperature, the solvent was evaporated to dryness and MeOH (20
mL) added to the residue to give a solid of 6, which was filtered
and washed with Et2O (30 mL). Yield: 0.4315 g, 70%. Anal. Calcd
for C58H50P2Pt2: C, 58.12; H, 4.17. Found: C, 58.11; H, 4.53. IR
1
(Nujol, cm-1): ν 2094 (w, CtC). H NMR (300 MHz, CD2Cl2,
255 K, ppm): δ 6.3-7.9 (m, 32 H, Ph groups), 2.85 (s, 3 H, Me),
2.69 (s, 2 H, CH2), 2.64 (s, 3 H, Me). 13C NMR (400 MHz, CD2-
Cl2, 293 K, ppm): δ 163-124 (CPh, C∧P, PPh3, 116.04 (m, CRt
C), 110.32 (s, CtCâ), 26.41 (s, JPt-C ) 452.6 Hz, CH2) , 23.44 (s,
Me). 31P NMR (400 MHz, CD2Cl2, 293 K, ppm): δ 32.6 (νA),
1
(Nujol, cm-1): ν 1962 (m, CtC). H NMR (300 MHz, CDCl3,
2
1
25.6 (νB, JP
) 433 Hz, JPt-P ) 2913 Hz).
A-PB
328 K, ppm): δ 6.7-7.5 (m, 34 H, Ph groups), 2.93 (s, 4 H, CH2,
(NBu4)[Pt(C∧P)(CtCPh)2Pd(C6F5)2] (11). [Pd(C6F5)2(THF)2]
(0.0815 g, 0.139 mmol) was added to a solution of 2 (0.1314 g,
0.139 mmol) in CH2Cl2 (20 mL) under an Ar atmosphere. After
25 min of stirring, the solvent was evaporated to dryness and
n-hexane (15 mL) added to the residue to give 11. Yield: 0.16 g,
83%. Anal. Calcd for C65 F10H66NPPdPt: C, 56.43; H, 4.81; N,
1.01. Found: C, 55.94; H, 4.34; N, 0.92. IR (Nujol, cm-1): ν 2033
(m, CtC), 788 (s, C6F5 , X-sensitive), 775 (s, C6F5 , X-sensitive).
1H NMR (300 MHz, CD2Cl2, 293 K) δ (ppm): 6.8-7.7 (m, 22 H,
2JPt-H ) 72.6 Hz), 2.64 (s, 12 H, Me). 31P NMR (300 MHz, CDCl3,
1
328K, ppm): δ 25.1 (s, JPt-P ) 4190 Hz).
Method B. A solution of nLiBu (1.375 mmol) in THF (15 mL)
was added to a solution of HCCPh (0.1555 mL, 1.374 mmol) in
THF at low temperature (ca. -20 °C) under an argon atmosphere.
After 15 min of stirring, [{Pt(C∧P)(µ-Cl)}2] (0.667 g, 0.625 mmol)
was added to it and allowed to react at room temperature for 15 h.
The resulting mixture was evaporated to dryness. MeOH (60 mL)
was added to the residue to give a solid of 6, which was filtered
and washed with Et2O (50 mL) and air-dried. Yield: 0.454 g, 61%.
[Pt(C∧P)(CtCPh)(CO)] (7). CO(g) was bubbled through a
stirred solution of 6 (0.1130 g, 0.1885 mmol) in CHCl3 for 2 h.
The resulting solution was evaporated to 3 mL, and CO(g) was
additionally bubbled for 30 min. Addition of Et2O (20 mL) to the
resulting solution gives a white solid of 7. Yield: 0.0795 g; 67%.
Anal. Calcd for C30H25OPPt: C, 57.42; H, 3.98. Found C, 57.26;
H, 4.00. IR (Nujol, cm-1): ν 2079 (w, CtO), 2127 (w, CtC). 1H
NMR (300 MHz, CD2Cl2, 293 K, ppm): δ 6.8-7.7 (m, 17 H, Ph
2
Ph groups), 3.34 (s, 2 H, CH2, JPt-H ) 67.5 Hz), 2.98 (m, 8 H,
CH2, NBu4+), 2.83 (s, br, 3 H, CH3), 2.60 (s, br, 3 H, CH3), 1.48
(m, 8 H, CH2, NBu4+), 1.33 (m, 8 H, CH2, NBu4+), 0.94 (t, 3JH-H
) 7.2 Hz, 12 H, CH3, NBu4+). 19F NMR (300 MHz, CD2Cl2, 293
K): δ -113.06 (d, 2 Fo, Jo-m ) 210.05 Hz). -114.03 (d, 2 Fo,
Jo-m ) 210.05 Hz), -165.51 (t, 1 Fp, Jp-m ) 20.08 Hz), -165.76
(t, 1 Fp, Jp-m ) 20.08 Hz), -166.59 (m, 2 Fm), -166.97 (m, 2 Fm)
1
ppm. 31P NMR (300 MHz, CD2Cl2, 293 K): δ 33.3 (s, JPt-P
)
3013 Hz). ΛM ) 47.92 Ω-1 cm2 mol-1 (solution 5.06 × 10-4 M in
acetone).
2
groups), 3.64 (s, 2 H, CH2, JPt-H ) 71.4 Hz), 2.52 (s, 6 H, Me).
(NBu4)[Pt(C∧P)(CtCPh)2Pt(C6F5)2] (12). [Pt(C6F5)2(THF)2]
(0.0885 g, 0.131 mmol) was added to a solution of 2 (0.1240 g,
0.131 mmol) in CH2Cl2 (20 mL) under an Ar atmosphere. After
30 min of stirring, the solvent was evaporated to dryness and MeOH
(15 mL) added to the residue. The MeOH solution was evaporated
to dryness and diethyl ether added to the residue to give 12. Yield:
0.0635 g, 41%. Anal. Calcd for C65H66F10NPPt2: C, 53.03; H, 4.48;
N, 0.95. Found: C, 53.16; H, 4.29; N, 0.90. IR (Nujol, cm-1): ν
1957 (m, CtC), 800 (s, C6F5, X-sensitive), 789 (s, C6F5, X-
sensitive). 1H NMR (300 MHz, CD2Cl2, 293 K, ppm): δ 6.5-7.6
(m, 22 H, Ph groups), 3.04 (m, 10 H, CH2, C∧P and NBu4+), 2.75
(s, 6 H, Me, C∧P). 1.52 (m, 8 H, CH2, NBu4+), 1.37 (m, 8 H,
13C NMR (400 MHz, CD2Cl2, 273 K, ppm): δ 177.72 (d, CO,
2JP-C ) 5.9 Hz, JPt-C ) 967.0 Hz), 160-125 (CPh), 106.82 (d,
2
3JP-C ) 29.3 Hz, CâtC), 101.85 (d, JP-C ) 134.2 Hz, CRtC),
29.55 (s, JPt-C ) 537.4 Hz, CH2), 23.34 (s, Me), 22.43 (s, Me).
1
31P NMR (300 MHz, CD2Cl2, 293 K, ppm): δ 33.6 (s, JPt-P
2448 Hz).
)
[Pt(C∧P)(CtCPh)(py)] (8). Py (1 mL, 12.41 mmol) was added
to a stirred solution of 6 (0.10 g, 0.1668 mmol) in CHCl3. After 1
h of stirring, the solvent was removed and Et2O (20 mL) was added
to the residue to give 8. Yield: 0.0683 g, 60%; Anal. Calcd for
C34H30NPPt: C, 60.20; H, 4.42; N, 2.06. Found: C, 60.10; H, 4.36;
N, 2.13. IR (Nujol, cm-1): ν 2102 (w, CtC). 1H NMR (300 MHz,
CDCl3, 293 K, ppm): δ 8.73 (d, 3JH -H ) 4.8 Hz, 2 H, Ho (py)),
CH2, NBu4+), 0.95 (t, JH-H ) 7.2 Hz, 12 H, Me, NBu4+). 19F
3
o
m
3
NMR (300 MHz, CD2Cl2, 293 K, ppm): δ -116.69 (d, 2 Fo, Jo-m
) 23.7 Hz, JPt-F ) 492.8 Hz), -116.98 (d, 2 Fo, Jo-m ) 23.7 Hz,
JPt-F ) 359.6 Hz), -166.991 (t, 1 Fp, Jp-m ) 20.08 Hz), -167.49
(m, 2 Fm), -167.72 (t, 1 Fp, Jp-m ) 20.08 Hz), -168.29 (m, 2
Fm). 31P NMR (300 MHz, CD2Cl2, 293 K, ppm): δ 27.9 (s, 1JPt-P
7.62 (t, JH -H ) 7.4 Hz, 1 H, Hp (py)), 6.8-7.7 (m, 19 H, Ph
p
m
2
groups, Hm (py)), 3.75 (s, 2 H, CH2, JPt-H ) 84.0 Hz), 2.59 (s, 3
H, Me), 1.89 (s, 3 H, Me). 13C NMR (400 MHz, CD2Cl2, 300 K,
2
ppm): δ 162-123 (CPh, C∧P, py), 121.25 (d, JP-C ) 152.3 Hz,
CRtC), 100.51 (d, 3JP-C ) 31.7 Hz, CtCâ), 23.14 (s, Me), 21.87
(s, Me), 5.85 (s, JPt-C ) 637.3 Hz, CH2). 31P NMR (300 MHz,
) 4223 Hz). ΛM ) 45.11 Ω-1 cm2 mol-1 (solution 5.5 × 10-4
M
1
in acetone).
CD2Cl2, 293 K, ppm): δ 35.4 (s, JPt-P ) 2742 Hz).
(NBu4)[Pt(C6F5)2(CtCPh)(PPh3)] (13). PPh3 (0.088 g, 0.335
mmol) was added to a stirred solution of (NBu4)[Pt(C∧P)(CtCPh)2-
Pt(C6F5)2] (12; 0.16 g, 0167 mmol) in distilled CH2Cl2 (15 mL),
and the mixture was allowed to react for 1 h. The solvent was
[Pt(C∧P)(CtCPh)(tht)] (9). THT (0.3 mL, 3.40 mmol) was
added to a stirred solution of 6 (0.1807 g, 0.3015 mmol) in CHCl3
(15 mL) and the mixture allowed to react for 2 h. The resulting
solution was evaporated to dryness and MeOH (20 mL) added to

Mono- and Polynuclear Alkynyl Complexes
Organometallics, Vol. 26, No. 7, 2007 1685
Table 6. Crystal Data and Structure Refinement for [NBu4][Pt(C∧P)(CtCPh)2] (2), [{Pt(C∧P)(CtCPh)2Cu}2] (3),
[{Pt(C∧P)(µ-CtCPh)}2] (6), and [Pt(C∧P)(CtCPh)(CO)]‚Me2CO (7‚Me2CO)
2
3
6
7‚Me2CO
empirical formula
unit cell dimens
a (Å)
b (Å)
c (Å)
C53H66NPPt
C74H60Cu2P2Pt2
C58H50P2Pt2
C30H26OPPt‚Me2CO
13.0788(7)
24.1198(12)
15.2094(7)
108.200(1)
6020.0(4), 4
12.3290(4)
12.3290(4)
39.6043(17)
90
13.7767(4)
7.8071(3)
22.3544(6)
99.827(2)
23.401(4)
14.738(2)
6.089(2)
101.186(3)
5443.4(14), 8
â (deg)
V (Å3), Z
6020.0(4), 4
2369.07(13), 2
0.710 73
100(1)
wavelength (Å)
temp (K)
radiation
cryst syst
graphite monochromated Mo KR
monoclinic
P21/n
tetragonal
P41
monoclinic
monoclinic
C2/c
space group
cryst dimens (mm)
P2/n
0.39 × 0.31 × 0.21
0.40 × 0.40 × 0.28
0.39 × 0.12 × 0.02
0.42 × 0.38 × 0.12
abs coeff (mm-1
diffractometer
)
3.149
5.426
6.004
5.243
Bruker SMART
3.28-50.08
25 060
Bruker SMART
3.30-50.02
33 378
Oxford Diffraction Xcalibur
3.92-49.34
14 214
Bruker SMART
3.18-50.02
14 621
2θ range for data collecn (deg)
no. of rflns collected
no. of indep rflns (R(int))
refinement method
goodness of fit on F2 b
final R indices (I > 2σ(I))a
R1
8050 (0.0347)
10 293 (0.0218)
3984 (0.0211)
4788 (0.0190)
full-matrix least squares on F2
1.007
1.023
1.023
1.023
0.0319
0.0487
0.0188
0.0454
0.0180
0.0398
0.0274
0.0726
wR2
R indices (all data)
R1
wR2
0.0467
0.0506
0.0194
0.0455
0.0206
0.0407
0.0305
0.0745
2
2
2
2
2
a R1 ) ∑(|Fo| - |Fc|)/∑|Fo|. wR2 ) [∑w(Fo - Fc )2/∑w(Fo )2]1/2
. .
b Goodness of fit ) [∑w(Fo - Fc )2/(nobservns - nparams)]1/2
evaporated to dryness and MeOH (20 mL) added to the residue, to
eliminate the solid (10). From the filtered solution, the evaporat-
ion of the solvent to dryness and addition of Et2O (20 mL) rendered
a white solid of 13. Yield: 0.1170 g, 62%. Anal. Calcd for
C54H56F10NPPt: C, 57.14; H, 4.97; N, 1.23. Found: C, 56.94; H,
4.40; N, 1.13. IR (Nujol, cm-1): ν 2104 (m, CtC), 800 (s, C6F5,
X-sensitive), 777 (s, C6F5, X-sensitive). 1H NMR (300 MHz,
CD2Cl2, 293 K, ppm): δ 7.74 (m, 6 H, PPh3), 7.32 (m, 9 H, PPh3),
6.97 (m, 3 H, CtCPh), 6.74 (m, 2 H, CtCPh), 3.0 (m, 8 H, CH2,
NBu4+), 1.51 (m, 8 H, CH2, NBu4+), 1.37 (m, 8 H, CH2, NBu4+),
0.99 (t, 3JH-H ) 7.2 Hz, 12 H, Me, NBu4+). 19F NMR (300 MHz,
CD2Cl2, 293 K): δ -116.49 (m, 2 Fo, JPt-F ) 422.4 Hz), -116.82
(d, 2 Fo, Jo-m ) 27.9 Hz, JPt-F ) 349.4 Hz), -166.77 (m, 2 Fm),
The structures were solved by Patterson and Fourier methods.
All refinements were carried out using the program SHELXL-97.125
All non-hydrogen atoms were assigned anisotropic displacement
parameters and refined without positional constraints, except as
noted below. All hydrogen atoms were constrained to idealized
geometries and assigned isotropic displacement parameters 1.2 times
the Uiso value of their attached carbon atoms (1.5 times for methyl
hydrogen atoms). For 2, during the refinement of the structure it
was found that one of the acetylide groups and the o-tolyl groups
of the phosphine ligand are disordered over two positions with 0.5
occupancy. Several models were tested, and finally the one that
gave the best results was kept. In this model, the pairs of homo-
logous atoms of the two sets were refined with the same anisotropic
displacement parameters. It was also found that a -CH2CH3
-166.99 (m, 1 Fp), -167.41 (m, 2 Fm), -168.09 (t, 1 Fp, Jp-m
)
19.9 Hz). 31P NMR (400 MHz, CD2Cl2, 293 K, ppm): δ 16.5 (s,
1JPt-P ) 2543 Hz).
+
fragment of the NBu4 cation was disordered over two positions
with partial occupancy 0.7/0.3. The interatomic distances of these
disordered fragments were constrained to sensible values. Full-
matrix least-squares refinement of these models against F2 con-
verged to the final residual indices given in Table 6.
X-ray Structure Determination. Crystal data and other details
of the structure analysis are presented in Table 6. Suitable crystals
of 2, 3, 6, and 7‚Me2CO were obtained by slow diffusion of
n-hexane into a CH2Cl2 solution at 5 °C of complexes 2 and 6, by
slow diffusion of methanol in a CHCl3 solution of complex 3 (at 5
°C), and by slow diffusion of methanol in an acetone solution of
complex 7 (at -30 °C). Crystals were mounted at the end of a
glass fiber. For 2, unit cell dimensions were determined from the
positions of 6094 reflections from the main data set. For 3, unit
cell dimensions were determined from the positions of 7887
reflections from the main data set. For 6, unit cell dimensions were
determined from the positions of 17 793 reflections from the main
data set. For 7‚Me2CO, unit cell dimensions were determined from
the positions of 914 reflections from the main data set. The
diffraction frames were integrated using the SAINT package59 for
2, 3, and 7‚Me2CO and the CrysAlis RED package123 for 6 and
corrected for absorption with SADABS124 in the three cases. Lorentz
and polarization corrections were applied for the three structures.
Acknowledgment. This work was supported by the Spanish
MCYT (DGI)/FEDER (Project CTQ2005-08606-C02-01) and
the Gobierno de Arago´n (Grupo de Excelencia: Qu´ımica
Inorga´nica y de los Compuestos Organometa´licos). We thank
Prof. J. Vicente (University of Murcia) for helpful discussions.
Supporting Information Available: CIF files giving X-ray
structural data for 2, 3, 6, and 7‚Me2CO. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM061102M
(124) Sheldrick, G. M. SADABS, Empirical Absorption Correction
Program; University of Go¨ttingen, Go¨ttingen, Germany, 1996.
(125) Sheldrick, G. M. SHELXL-97, a Program for Crystal Structure
Determination; University of Go¨ttingen, Go¨ttingen, Germany, 1997.
(123) CrysAlis RED, CCD Camera Data Reduction Program; Oxford
Diffraction, Oxford, U.K., 2004.