Stable η1-alkynyl-μ,η1:η2-alkenyl complexes from the reaction of terminal alkynes with encumbered dinuclear platinum compounds and their formyl, methoxycarbonyl, and hydride derivatives

Article abstract of DOI:10.1021/om020133o

A study was performed on the stepwise reaction of terminal alkynes with encumbered dinuclear platinum compounds and their formyl, methoxycarbonyl and hydride derivatives. The electrophilic carbonyl ligand was attacked by nucleophiles to give a rare platin

Full text of DOI:10.1021/om020133o

Organometallics 2002, 21, 2575-2577
2575
Sta ble η1-Alk yn yl-µ,η1:η2-Alk en yl Com p lexes fr om th e
Rea ction of Ter m in a l Alk yn es w ith En cu m ber ed
Din u clea r P la tin u m Com p ou n d s a n d Th eir F or m yl,
Meth oxyca r bon yl, a n d Hyd r id e Der iva tives
Simona Crementieri, Piero Leoni,* Fabio Marchetti, Lorella Marchetti, and
Marco Pasquali
Dipartimento di Chimica e Chimica Industriale, Universita` di Pisa, via Risorgimento 35.
I-56126 Pisa, Italy
Received February 19, 2002
Summary: The stepwise reaction of terminal alkynes
ecules before the product-forming σ-bond metathesis (or
with [(OC)Pt(µ-PBut ) Pt(H)(PBut H)]OTf yields inter-
reductive elimination) step may elongate the oligomer
2 2
2
mediate η1-alkynyl-hydride-bridged complexes, and
then stable η1-alkynyl/ alkenyl-bridged derivatives con-
taining an electrophilic carbonyl ligand. The latter is
attacked by nucleophiles (H- and MeO-) to give a rare
platinum formyl species, which is slowly converted into
a stable hydride or a stable methoxycarbonyl complex.
chain.1b
Polynuclear systems may offer alternative coordina-
tion modes and reaction paths to the various function-
alities,4 therefore providing new opportunities to cata-
lyst design. Indeed, most of the aforementioned single
steps have their well-established analogues in di- or
polynuclear complexes. However, up to now the obser-
vation of a sequence of such steps, gathering fragments
from two or more 1-alkyne molecules on the same poly-
nuclear framework, is sporadic. Relevant examples are
the isolation of vinyl-alkynyl-vinylidene,5 vinyl-,6
vinylidene-,7 or alkynyl-alkyne,8 bis(alkynyl)8,9 and
ene-diyne9b complexes, and the suggested intermediacy
of alkynyl-vinylidene or -allenylidene derivatives10
followed by CC coupling and the formation of dinuclear
metallacycles. To the best of our knowledge, the comple-
tion of an entire catalytic cycle has been demonstrated
only once.11
Linear oligomerizations of terminal alkynes to give
enynes or butatrienes are catalyzed by several mono-
nuclear metal complexes.1-3 The C-H bond is generally
activated through oxidative addition2j,k,m or σ-bond
metathesis1a,b,2c,l to give an alkynyl-hydride (or vi-
nylidene) or an alkynyl complex, respectively. This step
is followed by the formation of a C-C bond through the
insertion of a second alkyne into the metal-alkynyl or
-vinylidene bond1a,b,2a-f,l-n or, more rarely and after
alkyne insertion into the metal-hydride bond, by alkyn-
yl-vinyl coupling.2k Further insertions of alkyne mol-
Herein is described the stepwise reactions of 1-alkynes
with [(OC)Pt(µ-PBut ) Pt(H)(PBut H)]OTf (1; Tf ) CF3-
2 2
2
SO2),12 which eventually afford new η1-alkynyl-µ,η1:η2-
alkenyl derivatives, as well as some interesting aspects
of their reactivity. Complex 1 reacts reversibly with an
equimolar amount of PhCCH or with a 3/1 excess of
(1) (a) Hf: Yoshida, M.; J ordan, R. F. Organometallics 1997, 16,
4508. (b) Zr: Horton, A. D. J . Chem. Soc., Chem. Commun. 1992, 185.
(c) Ti: Varga, V. Petrusova, L.; Cejka, J .; Mach, K. J . Organomet.
Chem. 1997, 532, 251.
(2) (a) Ru: Wakatsuki, Y.; Yamazaki, H.; Kumegawa, N.; Satoh, T.;
Satoh, J . Y. J . Am. Chem.. Soc. 1991, 113, 9604. (b) Ru: Yi, C. S.; Liu,
N. Organometallics 1996, 15, 3968. (c) Ru: Slugovc, C.; Mereiter, K.;
Zobetz, E.; Schmid, R.; Kirchner, K. Organometallics 1996, 15, 5275.
(d) Ru: Dahlenburg, L.; Frosin, K. M.; Kerstan, S.; Werner, D. J .
Organomet. Chem. 1991, 407, 115. (e) Ru: Bianchini, C.; Frediani, P.;
Masi, D.; Peruzzini, M.; Zanobini, F. Organometallics 1994, 13, 4616.
(f) Ru: Echavarren, A. M.; Lopez, J .; Santoz, A.; Montoya, J . J .
Organomet. Chem. 1991, 414, 393. (g) Ru: J imenez-Tenorio, M. A.;
J imenez-Tenorio, M.; Puerta, M. C.; Valerga, P. Organometallics 2000,
19, 1333. (h) Fe: Field, L. D.; Messerle, B. A.; Smernik, R. J .; Hambley,
T. W.; Turner, P. J . Chem. Soc., Dalton Trans. 1999, 2557. (i) Os:
Barbaro, P.; Bianchini, C.; Peruzzini, M.; Polo, A.; Zanobini, F.;
Frediani, P. Inorg. Chim. Acta 1994, 220, 5. (j) Rh: Boese, W. T.;
Goldman, A. S. Organometallics 1991, 10, 782. (k) Rh: Kovalev, I. P.;
Yerdakov, K. V.; Strelenko, Yu. A.; Vinogradov, M. G.; Nikishin, G. I.
J . Organomet. Chem. 1990, 386, 139. (l) Rh: Schaefer, M.; Mahr, N.;
Wolf, J .; Werner, H. Angew. Chem., Int. Ed. Engl. 1993, 32, 1315. (m)
Ir: Ohmura, T.; Yorozuya, S.; Yamamoto, Y.; Miyaura, N. Organome-
tallics 2000, 19, 365. (n) Pd: Trost, B. M.; Sorum, M. T.; Chan, C.;
Harmas, A. E.; Ruehter, G. J . Am. Chem. Soc. 1997, 119, 698.
(3) (a) Sc: Thompson, M. E.; Baxter, S. M.; Bulls, A. R.; Burger, B.
J .; Nolan, M. C.; Santarsiero, B. D.; Shaefer, W. P.; Bercaw, J . E. J .
Am. Chem. Soc. 1987, 109, 203. (b) Y: Schaverien, C. J . Organome-
tallics 1994, 13, 69. (c) Sc: St. Clair, M.; Schaefer, W. P.; Bercaw, J .
E. Organometallics 1991, 10, 525. (d) Th, U: Hasket, A.; Wang, J . Q.;
Straub, T.; Neyroud, T. G.; Eisen, M. S. J . Am. Chem. Soc. 1999, 121,
3025. (d) U: Wong, J . Q.; Dash, A. K.; Berthet, J . C.; Ephritikhine,
M.; Eisen, M. S.. Organometallics 1999, 18, 2407. (e) Sm: Evans, W.
J .; Keyer, R. A.; Ziller, J . W. Organometallics 1993, 12, 2618.
ButCCH to give the hydride-bridged [(η1-RCC)(But HP)-
2
Pt(µ-PBut )(µ-H)Pt(CO)(PBut H)]OTf, (2a , R ) Ph; 2b,
2
2
R ) But; Scheme 1).13 The reactions proceed through
the formation of a P-H bond by coupling of the hydride
and the adjacent phosphide14 and the oxidative addition
(4) Suss-Fink, G.; Meister, G. Adv. Organomet. Chem. 1993, 35, 41.
(5) Kuncheria, J .; Mirza, H. A.; Vittal, J . J .; Puddephatt, R. J . Inorg.
Chem. Commun. 1999, 2, 197.
(6) Rashidi, M.; Puddephatt, R. J . Organometallics 1988, 7, 1636.
(7) Torkelson, J . R.; McDonald, R.; Cowie, M. Organometallics 1999,
18, 4134.
(8) George, D. A. S.; McDonald, R.; Cowie, M. Organometallics 1998,
17, 2553.
(9) (a) J imenez, M. V.; Sola, E.; Martinez, A. P.; Lahoz, F. J .; Oro,
L. A. Organometallics 1999, 18, 1125. (b) Matsuzaka, H.; Mizobe, Y.;
Nishio, M.; Hidai, M. J . Chem. Soc., Chem. Commun. 1991, 1011. (c)
Matsuzaka, H.; Hirayama, Y.; Nishio, M.; Mizobe, Y.; Hidai, M
Organometallics 1993, 12, 36.
(10) (a) Matsuzaka, H.; Koizumi, H.; Takagi, Y.; Nishio, M.; Hidai,
M. J . Am. Chem. Soc. 1993, 115, 10396. (b) Takagi, Y.; Matsuzaka,
H.; Ishii, Y.; Hidai, M. Organometallics 1997, 16, 4445. (c) Matsuzaka,
H.; Takagi, Y.; Hidai, M. Organometallics 1994, 13, 13.
(11) Matsuzaka, H.; Takagi, Y.; Ishii, Y.; Nishio, M.; Hidai, M.
Organometallics 1995, 14, 2153.
(12) Leoni, P.; Pasquali, M.; Cittadini, V.; Fortunelli, A.; Selmi, M.
Inorg. Chem. 1999, 38, 5257.
10.1021/om020133o CCC: $22.00 © 2002 American Chemical Society
Publication on Web 05/22/2002

2576 Organometallics, Vol. 21, No. 13, 2002
Communications
Sch em e 1
of the C-H bond of the alkyne. This is clearly demon-
characterized by elemental and spectroscopic analyses16
and by single-crystal X-ray diffraction.17 The structure
of cation 3+ is shown in Figure 1 together with some
relevant geometric parameters. Pt and P atoms, C(3),
and the carbonyl and phenylethynyl ligands approxi-
mately lie on a plane (maximum deviation 0.16 Å); the
phenyl group of the phenylethenyl ligand is perpen-
dicular (87°) to the same plane.
strated by the selective formation of [(η1-PhCC)(But -
2
HP)Pt(µ-PBut )(µ-D)Pt(CO)(PBut H)]OTf, (2a -D) in the
2
2
reaction of 1 with PhCCD.15
While 2b is stable indefinitely in the presence of an
excess of tert-butylacetylene, 2a , which decomposes
slowly to unidentified products on standing in solution,
reacts rapidly with an excess of phenylacetylene. In this
reaction the second alkyne unit is inserted into the Pt1-
Pt2(µ-H) moiety to give the alkenyl-bridged [(η1-PhCC)-
(But HP)Pt(µ-PBut )(µ,η1:η2-C(Ph)dCH2)Pt(CO)(PBut H)]-
Cation 3+ contains a single phosphide ligand bridging
two nonbonded platinum centers (Pt(1)‚‚‚Pt(2) ) 3.567-
2
2
2
(16) Complex 3 was isolated as a stable, colorless solid (65% yield)
by reacting an acetone solution of 1 with a 2.5-fold excess of PhCCH
at -30 °C. Anal. Calcd for C41H68F3O4P3Pt2S: C, 41.1; H, 5.72.
Found: C, 40.8; H, 5.76. Complex 3* was prepared analogously, by
starting from 1*. 3-D2 was prepared by starting from 1 and PhCCD.
3: 1H NMR (CD2Cl2, 293 K) δ (ppm)# 1.00, 1.31, 1.49, 1.59, 1.69, 1.185
OTf (3) in nearly quantitative yield. Complex 3 was
(13) An acetone solution of 1 yields rapidly and quantitatively 2a
or 2b after the addition of an equimolar amount of PhCCH at -60 °C
or a 3-fold excess of t-BuCCH at room temperature. When it is warmed
to room temperature, 2a decomposes to a mixture of products, while
2b can be isolated as a stable, pale yellow solid (53%) by adding
n-hexane. Anal. Calcd for C32H66F3O4P3Pt2S: C, 35.3; H, 6.13. Found:
C, 35.6; H, 6.17. Complex 2a * was prepared as 2a by starting from
[(O13C)Pt(µ-PBut2)2Pt(H)(PBut2H)]OTf (1*). In this and in all following
references, # denotes values of J XPt from 195Pt satellites.12,14 2a : 1H
3
1
2
(all d, J HP ) 14.5-15.7 Hz, 54 H, CH3), 3.35 (d, J HP ) 374, J HPt
)
22 Hz, 1 H, PH), 4.54 (d, 1J HP ) 340, 2J HPt ) 20 Hz, 1 H, PH), 4.53 (m,
2J HPt ) 17.3, 61.6 Hz, 1 H, PhCC(H)H), 5.02 (m, J HPt ) 47.5 Hz, 1 H,
2
PhCC(H)H), 7.25, 7.50, 7.89 (all m, 10 H, Ph); 31P{1H} NMR (CD2Cl2,
293 K) δ (ppm)# -52.0 (dd, 2J P ) 199, 2J P ) 323, 1J P
) 1630,
3Pt1
3P1
3P2
1J P
) 2046 Hz, P3), 43.6 (dd, 2J P
) 323, 3J P
) 7.2, 1J P
) 1797 Hz, P1),
1Pt1
)
2Pt2
3Pt2
2P3
2P1
NMR (acetone-d6, 213 K) δ (ppm)# -5.1 (ddd, J HP ) 11, 13, 52, 1J HPt
)
1875 Hz, P2), 72.7 (dd, 2J P ) 199, 3J P ) 7.2, 1J P
1P3
1P2
1
402, 591 Hz, 1 H, µ-H), 1.2-1.8 (m, 54 H, CCH3), 5.5 (d, J HP ) 374
further splitting in the H-coupled spectrum for the signals at 43.6 (ddd,
1
3
2
Hz, 1 H, PH), 6.1 (dd, J HP ) 376, J HP ) 12, J HPt ) 44 Hz, 1 H, PH),
1J P2H ) 340 Hz) and at 72.7 (ddd, 1J P ) 374 Hz); 195Pt{1H} NMR
1H
7.2-7.6 (m, 5 H, C6H5); 31P{1H} NMR (acetone-d6, 213 K)# δ (ppm)
(CD2Cl2, 293 K) δ (ppm) -4167 (dd, J Pt ) 2046, J Pt ) 1875 Hz,
1
1
2P3
2P2
23.9 (s, 1J P
) 3782, 2J P
) 373 Hz, P1), 39.4 (d, 2J P
) 150,
Pt2), -4406 (dd, J Pt ) 1630, J Pt ) 797 Hz, Pt1); 13C{1H} NMR
1
1
1Pt1
1Pt2
2P3
P
P
1
3
1
1
1J P
) 1970 Hz, P2), 212.3 (d, 2J P ) 150, 1J P
) 1963, 1J P
)
(CD2Cl2, 293 K) δ (ppm)# 30.5-31.5, 32.7, 33.9 (all br s, PCCH3), 33.3,
2Pt2
2P3
3Pt1
3Pt2
1260 Hz, P3), further splitting in the H-coupled spectrum for the signals
35.2, 35.8, 36.8, (w d, 1J CP ) 20 Hz, PCCH3), 38.8, 38.9 (w m, PCCH3),
at 23.9 (d, J HP ) ca. 375 Hz) and 39.4 (dd, J HP ) ca. 375); 195Pt{1H}
87.1 (w s, J CPt ) 770 Hz, PhCC), 88.2 (w s, J CPt ) 112, 77 Hz, PhCCH2
1
1
1
1
1
NMR (acetone-d6, 213 K) δ (ppm) -5559 (dd, J Pt ) 3782, J Pt
)
1P3
(t in the proton-coupled spectrum, J CH ) 158 Hz)), 117.6 (w s, J CPt
)
1P1
1
1
2
1963 Hz, Pt1), -5677 (ddd, J Pt ) 1970, J Pt ) 1260, J Pt ) 373
403 Hz, PhCC), 121.3 (q, 1J CF ) 320 Hz, CF3) 126.7, 128.4, 128.9, 130.1,
Hz, Pt2); IR (CHCl3) 2097 s (ν2CP2O) cm-1. 2a *: 31P{1H} and 1H NMR
130.3 (all s, Ph), 144.5 (w s, J CPt ) 22 Hz, PhCCH2), 181.9 (w s, J CPt )
2P2
2P1
spectra as for 2a ; 195Pt{1H} NMR (acetone-d6, 213 K) δ (ppm) -5559
1070 Hz, CO); IR (CHCl3) 2116 w (νCC), 2086 s (νCO) cm-1. 3*: same
signals as complex 3, except further splitting for the signal at -4167
1
(dd as for 2a , Pt1), -5677 (dddd, J PtP as for 2a and J Pt ) 1780 Hz,
3C
Pt2); 13C{1H} NMR (acetone-d6, 213 K) δ (ppm)# 28.1-33.5 (m, CCH3),
ppm (1J Pt ) 1070 Hz) in the 195Pt{1H} NMR, the intensity of the
2C
126.5-132.9 (all s, Ph), 175.6 (strong s, J CPt ) 1780 Hz, CO). 2b: 1H
signal at 181.9 ppm (strong s) in the 13C{1H} NMR, and a shift in the
νCO absorption (2036 cm-1) in the IR spectrum. 3-D2: same signals as
for 3, except those missing at 4.53 and 5.02 ppm in the 1H NMR.
(17) Crystal structure analysis of 3‚OC4H8: C46H76F3O5P3Pt2S,
Mr ) 1281.22, triclinic, space group P1h, a ) 9.184(1) Å, b ) 11.799(2)
Å, c ) 25.968(5) Å, R ) 88.69(1)°, â ) 89.73(1)°, γ ) 72.54(1)°, V )
2683.6(7) Å3, Z ) 2, F(000) ) 1272, Dc ) 1.586 Mg m-3, T ) 293 K,
crystal dimensions 0.76 × 0.48 × 0.09 mm3. Intensity data were
collected on a Bruker P4 diffractometer with graphite-monochromated
Mo KR radiation (λ ) 0.710 73 Å); 5070 nonzero (2σ) out of 6945
independent reflections were collected (Rint ) 0.0655) with 2.32 e θ e
22.50°. The structure was solved by standard Patterson and Fourier
methods (SHELX-97) and refined by least squares on F 2 (SHELXTL).
R1 ) 0.0814, wR2 ) 0.1868; 463 parameters were refined. Pt, S, P,
and F are anisotropic, O and C are generally anisotropic, except for
some tert-butyl groups and those of the solvent thf molecule, and H is
isotropic. The final difference Fourier map showed residuals of electron
density high up to 3.166 e Å-3. This residuals may be due to the
disorder in tert-butyl groups or, possibly, to an incomplete absorption
correction.
1
NMR (acetone-d6, 293 K) δ (ppm)# -5.1 (ddd, J HP ) 11, 12, 52, 1J HPt
)
406, 600 Hz, 1 H, µ-H), 1.2 (s, 9 H, CC-CCH3), 1.4-1.7 (three d,
3J HP ) 16 Hz, 54 H, PCCH3), 5.56 (d, 1J HP ) 370 Hz, 1 H, PH), 6.0 (dd,
1J HP ) 367, 3J HP ) 14, 2J HPt ) 42 Hz, 1 H, PH); 31P{1H} NMR (acetone-
d6, 293 K) δ (ppm)# 24.7 (s, 1J P
) 3838, 2J P
) 382 Hz, P1), 40.7
1Pt2
1Pt1
(d, 2J P ) 150, 1J P
) 1966 Hz, P2), 211.2 (d, 2J P ) 150, 1J P
)
3Pt1
2P3
2Pt2
2P3
1934, 1J P
) 1263 Hz, P3); 195Pt{1H} NMR (acetone-d6, 293 K) δ
1 1
3Pt2
(ppm) -5514 (dd, J Pt ) 3838, J Pt ) 1934 Hz, Pt1), -5623 (ddd,
1P1
1P3
1J Pt ) 1966, J Pt ) 1263, J Pt ) 382 Hz, Pt2); IR (CHCl3) 2092
1
2
2P2
2P3
2P1
s (νCO) cm-1
.
(14) (a) Fortunelli, A.; Leoni, P.; Marchetti, L.; Pasquali, M.; Sbrana,
F.; Selmi, M. Inorg. Chem. 2001, 40, 3055. (b) Leoni, P.; Manetti, S.;
Pasquali, M.; Albinati, A. Inorg. Chem. 1996, 35, 6045-6052.
(15) Complex 2a -D was prepared as for 2a , starting from 1 and
PhCCD. 2a -D: 1H NMR (acetone-d6, 213 K) as for 2a , except the
hydride signal is missing at -5.1 ppm; 31P{1H} and 31P NMR (acetone-
d6, 213 K) as for 2a ; 195Pt{1H} NMR (acetone-d6, 213 K) δ (ppm) -5559
1
1
1
(ddt, J Pt
and J Pt
2P3
as for 2a , J Pt ) 62 Hz, Pt1), -5677 (dddt,
1P1
1P3
1D
2
1
1J Pt
,
1J Pt and J Pt as for 2a , J Pt ) 91 Hz, Pt2).
2P2
2P1
2D

Communications
Organometallics, Vol. 21, No. 13, 2002 2577
alkynyl complex 3, obtained in the stepwise activation
of 1-alkynes, and its neutral acyl and hydride deriva-
tives 4-6 are interesting polyfunctional dinuclear com-
pounds. Further studies are in progress aimed at
comparing the reactivities of the various functions and
promoting C-C coupling reactions.
Ack n ow led gm en t. The Consiglio Nazionale delle
Ricerche (CNR) and MURST, Programmi di Interesse
Nazionale (2000-2001), are gratefully acknowledged for
financial support.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data, positional parameters for non-hydrogen and hydrogen
atoms, bond distances and angles, and anisotropic thermal
parameters and an ORTEP view with the full numbering
scheme for the structure of complex 3. This material is
available free of charge via the Internet at http://pubs.acs.org.
Figu r e 1. Molecular structure of the cation [(η1-PhCC)(But -
2
HP)Pt(µ-PBut )(µ,η1:η2-C(Ph)dCH2)Pt(CO)(PBut H)]+ ((3)+).
2
2
Only the Pt and P atoms are represented by 30% ellipsoids,
and most of the hydrogens are omitted for clarity. Main
bond distances (Å) and angles (deg): Pt(1)-C(10), 1.96(3);
Pt(1)-P(1), 2.340(7); Pt(1)-P(3), 2.352(7); Pt(1)-C(2), 2.25-
(2); Pt(1)-C(3), 2.37(2); Pt(2)-C(3), 2.07(2); Pt(2)-P(3),
2.361(7); Pt(2)-C(1), 1.92(2); Pt(2)-P(2), 2.365(7); C(2)-
C(3), 1.39(3); C(3)-C(4), 1.50(3); C(10)-Pt(1)-C(2), 162.1-
(10); C(10)-Pt(1)-P(1), 87.7(9); C(2)-Pt(1)-P(1), 86.8(7);
C(10)-Pt(1)-P(3), 94.3(9); C(2)-Pt(1)-P(3), 91.9(7); P(1)-
Pt(1)-P(3), 177.2(2); C(10)-Pt(1)-C(3), 162.4(10); C(2)-
Pt(1)-C(3), 35.0(8); P(1)-Pt(1)-C(3), 102.9(6); P(3)-Pt(1)-
C(3), 74.8(6); C(1)-Pt(2)-C(3), 177.3(9); C(1)-Pt(2)-P(3),
97.7(7); C(3)-Pt(2)-P(3), 80.3(7); C(1)-Pt(2)-P(2), 93.4-
(7); C(3)-Pt(2)-P(2), 88.4(7); P(3)-Pt(2)-P(2), 167.7(2);
C(3)-C(2)-Pt(1), 77.4(13); C(2)-C(3)-C(4), 119(2); C(2)-
C(3)-Pt(2), 118.5(16); C(4)-C(3)-Pt(2), 120.2(17); C(2)-
C(3)-Pt(1), 67.6(13); C(4)-C(3)-Pt(1), 108.6(15); Pt(2)-
C(3)-Pt(1), 106.5(10).
OM020133O
(18) Complex 4 was isolated (58% yield) as a pale yellow, unstable
solid by reacting 3 with a 10-fold excess of NaBH4 in methanol. 4*
was prepared analogously by starting from 3*. 4: 1H NMR (C6D6, 293
3
K) δ (ppm)# 0.73, 1.18, 1.33, 1.36, 1.92, 1.93 (all d, J HP ) 13.7-14.3
Hz, 54 H, PCCH3), 3.77 (d, 1J HP ) 330, 2J HPt ) 22 Hz, 1 H, P2H), 4.91
2
2
1
2
(d, J HP ) 410, J HPt ) 13 Hz, 1 H, P1H), 4.12 (m, 1 H, PhCC(H)H),
1
1
2
5.74 (m, J HPt ) 43 Hz, 1 H, PhCC(H)H), 7.09 (m, 6 H, Ph), 7.51 (d, 2
3
2
H, Ph), 7.79 (d, 2 H, Ph), 15.4 (dd, J HP ) 4.3, 12.9, J HPt ) 334 Hz, 1
H, CHO); 31P{1H} NMR (C6D6, 293 K) δ (ppm)# -35.3 2(dd, 2J P
)
3P1
324, 2J P
) 237, 1J P
) 2167, 1J P
2Pt2
) 2633 Hz, P3), 46.9 (dd,
3Pt2
3P2
3Pt1
2J P ) 237, 3J P ) 7.8, 1J P
) 2168 Hz, P2), 55.4 (dd, 2J P ) 324,
2P3
2P1
1P3
3J P ) 7.8, 1J P
) 2203 Hz, P1), further splitting in the H-coupled
1P2
1Pt1
spectrum for the signals at 43.9 (ddd, 1J P ) 330 Hz) and at 55.4 (ddd,
2H
1J P ) 410 Hz); 195Pt{1H} NMR (C6D6, 293 K) δ (ppm) -3700 (dd,
1H
1J Pt
) 2633, J Pt
) 2168 Hz, Pt2), -4254 (dd, J Pt
) 2167,
1P3
1
1
2P3
2P2
1J Pt
) 2203 Hz, Pt1), further splitting in the H-coupled spectrum
1P1
for the signals at -3700 ppm (ddd, J Pt ) 334 Hz); 13C{1H} NMR
1
2H
(C6D6, 293 K) δ (ppm)# 29.9-34.5 (m, PCCH3), 35.5, 35.9, 36.1, 36.5,
37.0, 37.9 (w s, PCCH3), 93.6 (w s, PhCCH2), 102.2 (w br s, J CPt ) 770
Hz, PhCC), 124.7, 127.3, 128.4, 130.1, 130.8 (all s, Ph), 217.0 (w s,
(2) Å), which are also terminally bonded to a secondary
phosphine (pseudo-trans with respect to the bridging P
nucleus) and a carbonyl (Pt(2)-C(1) ) 1.92(2) Å) or a
linear η1-alkynyl (Pt(1)-C(10) ) 1.96(3) Å) in a pseudo-
cis fashion to Pµ. The coordination spheres are com-
pleted by a bridging PhCCH2 vinyl group σ-bonded to
Pt(2) and π-bonded to Pt(1) (Pt(2)-C(3) ) 2.07(2) Å,
Pt(2)‚‚‚C(2) ) 3.00(2) Å, Pt(1)-C(2) ) 2.25(2) Å, Pt(1)-
C(3) ) 2.37(2) Å). All NMR spectra suggest that the
structure is maintained in solution. Complex 3 is air-
and moisture-stable and does not reductively eliminate
on warming the ene-yne by coupling of the carbyl
moieties. The more electrophilic center of the cation is
the carbonyl ligand, as indicated by the reactions with
nucleophiles. Actually, complex 3 reacts with NaBH4
and CH3OLi to give the corresponding acyl derivatives
CdO), further splitting in the H-coupled spectrum for the signals at
1
217.0 ppm (d, J CH ) 158 Hz); IR (KBr, Nujol) 1639 s (νCdO) cm-1
.
(19) 4*: same signals as 4 except those at 15.4 ppm (ddd) in the 1H
1
NMR, which split further due to J HC ) 158 Hz, and at 217.0 ppm in
the 13C{1H} (strong s, 1J CPt ) 1021 Hz) and 13C (strong d, 1J HC ) 158,
1J CPt ) 1021 Hz) NMR spe2ctra. The νCdO absorption is shifted to 1607
2
cm-1 in the IR spectrum.
(20) Leoni, P.; Marchetti, F.; Marchetti, L.; Pasquali, M.; Quaglierini,
S. Angew. Chem., Int. Ed. 2001, 40, 3617.
(21) Complex 5 was isolated (64% yield) as a colorless, stable solid
by reacting 3 with a 5-fold excess of LiOCH3 in methanol. Anal. Calcd
for C42H71O2P3Pt2: C, 46.2; H, 6.56. Found: C, 45.8; H, 6.72. 5: 1H
NMR (C6D6, 293 K) δ (ppm) 0.86, 1.28, 1.30, 1.38, 2.01, 2.06 (all d,
3J HP ) 14.3-16.0 Hz, 54 H, PCCH3), 3.47 (s, 3 H, OCH3), 3,71 (d,
1
1J HP ) 340 Hz, 1 H, PH), 4.63 (d, J HP ) 392 Hz, 1 H, PH), 4.92 (m,
1
1 H,2PhCC(H)H), 5.65 (m, 1 H, PhCC(H)H), 7.11 (m, 6 H, Ph), 7.69 (d,
2 H, Ph), 7.81 (d, 2 H, Ph); 31P{1H} NMR (C6D6, 293 K) δ (ppm)# -45.3
(dd, 2J P ) 318, 2J P ) 262, 1J P
) 2318, 1J P
) 1750 Hz, P3),
3Pt1
3P1
3P2
3Pt2
47.1 (d, 2J P
) 262, 1J P
) 1861 Hz, P2), 55.5 (d, 2J P
) 318,
1P3
2P3
2Pt2
1J P
) 2168 Hz, P1); IR (KBr, Nujol) 1652 s (νCdO) cm-1
.
1Pt1
(22) Complex 6 was isolated (70% yield) as a yellow, stable solid
after stirring for 3 days at room temperature a toluene solution of 4.
Anal. Calcd for C40H69P3Pt2: C, 46.5; H, 6.73. Found: C, 46.8; H, 6.68.
4 and 5, respectively. The formyl complex (η1-PhCC)(But -
2
HP)Pt(µ-PBut )(µ,η1:η2-C(Ph)dCH2)Pt(CHO)(PBut H)
2
2
6: 1H NMR (CD2Cl2, 293 K) δ (ppm)# -9.75 (dd, J HP ) 4.4, 18.0,
2
(4),18 whose structure was unambiguously confirmed by
the spectra of the labeled 13CHO species (4*),19 exhibits
a remarkably high thermal stability (τ1/2(dec) ) 5 h); it
is worth noting that formyl complexes of platinum were
unknown until recently.20 The methoxycarbonyl com-
pound (η1-PhCC)(But HP)Pt(µ-PBut )(µ,η1:η2-C(Ph)d
1J HPt ) 1415 Hz, 1 H, PtH), 0.81, 1.27, 1.31, 1.41, 1.56, 1.62 (all d,
2
J HP ) 13.3-14.1 Hz, 54 H, PCCH3), 2.75 (d, 1J HP ) 332 Hz, 1 H, PH),
3
1
3
2
4.10 (dd, J HP ) 314, J HP ) 4.2, J HPt ) 19 Hz, 1 H, PH), 4.17 (m,
J HPt ) 47 Hz, 21 H, PhCC(H3)H), 4.90 (d, J HP ) 3, J HPt ) 24, 38 Hz, 1 H,
2
PhCC(H)H), 7.0-7.2, 7.4, 7.7 (m, 10 H, Ph).; 31P{1H} NMR (C6D6, 293
K): δ (ppm)# -34.2 (dd, 2J P
) 318, 2J P
) 278, 1J P
) 2160,
3Pt1
3P1
3P2
1J P
) 2293 Hz, P3), 64.6 (dd, 2J P
) 278, 3J P
) 8.2, 1J P
)
2Pt2
3Pt2
2P3
2P1
2020 Hz, P2), 58.2 (dd, 2J P ) 318, 3J P ) 8.2, 1J P
) 2139 Hz),
2
2
1P3
1P2
1Pt1
CH2)Pt(COOCH3)(PBut H) (5)21 is stable for weeks both
further splitting in the H-coupled spectrum for the signals at 64.6 (ddd,
2
1J P ) 300 Hz) and 58.2 (ddd, 1J P ) 314 Hz); 195Pt{1H} NMR (C6D6,
293 K) δ (ppm) -4628 (dd, 1J Pt )2H2293, 1J Pt ) 2020 Hz, Pt2), -4249
2H
in solution and in the solid state. On warming at room
2P3
2P2
temperature complex 4 rapidly loses CO and is quan-
1
1
(dd J Pt
) 2160, J Pt
) 2139 Hz, Pt1), further splitting in the
1P1
1
1P3
titatively converted into the hydride (η1-PhCC)(But HP)-
H-coupled spectrum for the signals at -4628 (ddd, J Pt ) 1412 Hz);
2H
2
13C{1H} NMR (CD2Cl2, 293 K) δ (ppm) 30.0, 31.1, 32.7, 33.6 (all br s,
PCCH3) 34.0-37.0 (w br m, PCCH3), 93.6 (w s, J CPt ) 65 Hz, PhCCH2),
117.3 (s, J CPt ) 267 Hz, PhCC), 124.1, 126.5, 126.9, 128.0, 129.5, 130.3
(all s, Ph), 151.3 (w br s, J CPt ) 20 Hz, PhCCH2); IR (KBr, Nujol) 2120
Pt(µ-PBut )(µ,η1:η2-C(Ph)dCH2)Pt(H)(PBut H) (6).22
2
2
The present study confirms the ready accessibility of
the protected diplatinum site in 1. The cationic alkenyl-
w (νCC), 2096 s (νPtH) cm-1
.