Synthesis and reactivity of binuclear bis(μ-aryloxo) complexes of palladium and platinum. Crystal structure of [NBu4][Pt(C6F5)2(OC 6H4NO2-p)(CO)]

Article abstract of DOI:10.1021/om950409a

The hydroxo complexes [NBu₄]₂[{M(C₆F₅) ₂(μ-OH)}₂] (M = Pd, Pt) react with phenols ROH (1:2 molar ratio) to give the bis(μ-aryloxo) complexes [NBu₄]₂[{M(C₆F₅) ₂(μ-OR)}₂] (M = Pd, Pt; R = C₆H₅, p-MeC₆H₄, p-NO₂C₆H₄, C₆F₅). The reaction of bis(μ-aryloxo) complexes with PPh₃ (1:2 molar ratio) gives the aryloxo monomer complexes [NBu₄][M(C₆F₅)₂(OR)(PPh ₃)] (M = Pd, Pt; R = p-NO₂C₆H₄, C₆F₅). The platinum monocarbonyl complexes [NBu₄][Pt-(C₆F₅)₂(OR)(CO)] (R = p-NO₂C₆H₄, C₆F₅) have also been prepared by reaction of the corresponding bis(μ-aryloxo) complexes with carbon monoxide at room temperature and normal pressure. [NBu₄][Pd(C₆F₅)₃(CO)] is isolated in low yield from the reaction of [NBu₄]₂Pd(C₆F₅) ₂(μ-OC₆H₄NO₂-p)] with CO in the presence of water. The identity of the isolated complexes has been established by partial elemental analyses, conductance measurements, and spectroscopic (IR, ¹H, ¹⁹F, ³¹P) methods. A single-crystal diffraction study of [NBu₄][Pt(C₆F₅)₂(OC ₆H₄NO₂-p)(CO)] showed that coordination about platinum was approximately square-planar with the aryl rings tilted to avoid steric crowding.

Full text of DOI:10.1021/om950409a

1662
Organometallics 1996, 15, 1662-1668
Syn th esis a n d Rea ctivity of Bin u clea r Bis(µ-a r yloxo)
Com p lexes of P a lla d iu m a n d P la tin u m . Cr ysta l
Str u ctu r e of [NBu 4][P t(C6F 5)2(OC6H4NO2-p)(CO)]
J ose´ Ruiz, Venancio Rodr´ıguez, and Gregorio Lo´pez*
Departamento de Qu´ımica Inorga´nica, Universidad de Murcia, 30071-Murcia, Spain
Penny A. Chaloner and Peter B. Hitchcock
School of Chemistry and Molecular Sciences, University of Sussex, Brighton BN1 9QJ , U.K.
Received May 31, 1995X
The hydroxo complexes [NBu4]2[{M(C6F5)2(µ-OH)}2] (M ) Pd, Pt) react with phenols ROH
(1:2 molar ratio) to give the bis(µ-aryloxo) complexes [NBu4]2[{M(C6F5)2(µ-OR)}2] (M ) Pd,
Pt; R ) C6H5, p-MeC6H4, p-NO2C6H4, C6F5). The reaction of bis(µ-aryloxo) complexes with
PPh3 (1:2 molar ratio) gives the aryloxo monomer complexes [NBu4][M(C6F5)2(OR)(PPh3)]
(M ) Pd, Pt; R ) p-NO2C6H4, C6F5). The platinum monocarbonyl complexes [NBu4][Pt-
(C6F5)2(OR)(CO)] (R ) p-NO2C6H4, C6F5) have also been prepared by reaction of the
corresponding bis(µ-aryloxo) complexes with carbon monoxide at room temperature and
normal pressure. [NBu4][Pd(C6F5)3(CO)] is isolated in low yield from the reaction of
[NBu4]2[Pd(C6F5)2(µ-OC6H4NO2-p)] with CO in the presence of water. The identity of the
isolated complexes has been established by partial elemental analyses, conductance
measurements, and spectroscopic (IR, 1H, 19F, 31P) methods. A single-crystal diffraction study
of [NBu4][Pt(C6F5)2(OC6H4NO2-p)(CO)] showed that coordination about platinum was
approximately square-planar with the aryl rings tilted to avoid steric crowding.
In tr od u ction
and we have now examined the reactivity of [{M(C6F5)2-
(µ-OH)}2]2- (M ) Pd, Pt)14,15 toward some phenols in
order to form aryloxo-metal bonds. This paper deals
with the synthesis of a number of bis(µ-aryloxo) com-
plexes of palladium and platinum and their reactivity
toward the neutral π-aceptor ligands triphenylphos-
phine and carbon monoxide, which leads to the forma-
tion of monomeric aryloxo complexes containing these
ligands.
The chemistry of late transition metals alkoxides1 has
recently attracted growing attention partly because of
their relevance to organic synthesis, where late-transi-
tion-metal alkoxides are believed to be involved,2 and
partly because of their recently discovered unique
chemical reactions such as CO insertion into metal
alkoxide bonds3-6 and adduct formation with alcohols
through strong hydrogen bonding.7-11 Unfortunately,
the synthesis and reactivity of palladium and platinum
alkoxide and aryloxide complexes have been little
explored, probably because it was thought that Pd-O
and Pt-O bonds would be weak, but theoretical calcula-
tions have demonstrated that these bonds are of com-
parable strength to or stronger than the corresponding
metal-carbon bonds.12
Exp er im en ta l Section
In str u m en ta l Mea su r em en ts. C, H, and N analyses were
performed with a Carlo Erba Model EA 1108 microanalyzer.
Decomposition temperatures were determined with a Mettler
TG-50 thermobalance. Molar conductivities were measured
in acetone solution (c ≈ 5 × 10-4 mol dm-3) with a Crison 525
conductimeter. The NMR spectra were recorded on a Bruker
AC 200E (1H) or Varian Unity 300 (19F, 31P) spectrometer,
using SiMe4, CFCl3, and H3PO4 as standards, respectively.
We have recently reported13 on the synthesis of the
bis(µ-methoxo) complex [NBu4]2[{Pt(C6F5)2(µ-OMe)}2],
Infrared spectra were recorded on
spectrophotometer using Nujol mulls between polyethylene
sheets.
Ma ter ia ls. The precursors [NBu4]2[{M(C6F5)2(µ-OH)}2] (M
) Pd, Pt) were prepared as described elsewhere.14,15 Solvents
were dried by the usual methods.
P r ep a r a tion of Com p lexes 1-4, 7, a n d 8. To a solution
of [NBu4]2[{M(C6F5)2(µ-OH)}2] (0.071 mmol) in dichloromethane
a Perkin-Elmer 1430
X Abstract published in Advance ACS Abstracts, February 15, 1996.
(1) Bryndza, H. E.; Tam, W. Chem. Rev. 1988, 88, 1163.
(2) Heck, R. F. Palladium Reagents in Organic Syntheses; Aca-
demic: New York, 1985; p 341.
(3) Bennett, M. A.; Yoshida, T. J . Am. Chem. Soc. 1978, 100, 1750.
(4) Michelin, R. A.; Napoli, M.; Ros, R. J . Organomet. Chem. 1979,
175, 239.
(5) Bryndza, H. E.; Fong, L. K.; Paciello, R. A.; Tam, W.; Bercaw, J .
E. J . Am. Chem. Soc. 1987, 109, 1444.
(6) Bernard, K. A.; Atwood, J . D. Organometallics 1989, 8, 795.
(7) Kegley, S. E.; Schaverien, C. J .; Freudenberger, J . H.; Bergman,
R. G.; Nolan, S. P.; Hoff, C. D. J . Am. Chem. Soc. 1987, 109, 6563.
(8) Di Bugno, C.; Pasquali, M.; Leoni, P.; Sabatino, P.; Braga, D.
Inorg. Chem. 1989, 28, 1390.
(9) Kim, Y.-J .; Osakada, K.; Takenaka, A.; Yamamoto, A. J . Am.
Chem. Soc. 1990, 112, 1096.
(12) (a) Ba¨ckvall, J . E.; Bjorkman, E. E.; Peterson, L.; Siegbahn, R.
J . J . Am. Chem. Soc. 1984, 106, 4369. (b) Ibid. J . Am. Chem. Soc. 1985,
107, 7265.
(13) Lo´pez, G.; Ruiz, J .; Garc´ıa, G.; Vicente, C.; Rodr´ıguez, V.;
Sa´nchez, G.; Hermoso, J . A.; Martı´nez-Ripoll, M. J . Chem. Soc., Dalton
Trans. 1992, 1681.
(10) Osakada, K.; Kim, Y.-J .; Yamamoto, A. J . Organomet. Chem.
1990, 382, 303.
(11) Alsters, P. L.; Baesjou, P. J .; J anssen, M. D.; Kooijman, H.;
Sicherer-Roetman, A.; Spek, A. L.; van Koten, G. Organometallics 1992,
11, 4124.
(14) Lo´pez, G.; Ruiz, J .; Garc´ıa, G.; Vicente, C.; Casabo´, J .; Molins,
E.; Miravitlles, C. Inorg. Chem. 1991, 30, 2605.
(15) Lo´pez, G.; Ruiz, J .; Garc´ıa, G.; Vicente, C.; Mart´ı, J . M.;
Hermoso, J . A.; Vegas, A; Mart´ınez-Ripoll, M. J . Chem. Soc., Dalton
Trans. 1992, 53.
0276-7333/96/2315-1662$12.00/0 © 1996 American Chemical Society

Bis(µ-aryloxo) Complexes of Pd and Pt
Organometallics, Vol. 15, No. 6, 1996 1663
(6 cm3) was added the corresponding phenol, ROH (0.142
mmol), with constant stirring at room temperature for 1 h.
After partial evaporation of the solvent under reduced pres-
sure, addition of hexane caused the precipitation of white or
yellowish solids which were collected by filtration and crystal-
lized from dichloromethane-hexane. Complex 1: yield 93%;
mp 210 °C dec; ΛM 197 Ω-1 cm2 mol-1; IR (Nujol, cm-1) 775,
765 (Pd-C6F5). Anal. Calcd for C68H82N2F20O2Pd2: C, 52.6;
H, 5.3; N, 1.8. Found: C, 52.0; H, 5.4; N, 1.8. Complex 2:
yield 90%; mp 208 °C dec; ΛM 191 Ω-1 cm2 mol-1; IR (Nujol,
cm-1) 785, 770 (Pd-C6F5). Anal. Calcd for C70H86N2F20O2-
Pd2: C, 53.2; H, 5.5; N, 1.8. Found: C, 52.7; H, 5.5 N, 1.8.
Calcd for C35H36NF15O2Pt: C, 42.8; H, 3.7; N, 1.4. Found: C,
42.5; H, 3.9; N, 1.5.
R ea ct ion of Com p lex 3 w it h CO in t h e P r esen ce of
Wa ter . CO was passed through a dichloromethane (15 cm3)
solution of complex 3 (500 mg; 0.3045 mmol) and water (10.96
µL; 0.609 mmol) at room temperature for 20 min, and the
metallic palladium which formed was removed by filtration.
The resulting clear solution was vacuum-concentrated to ca.
one-third the original volume. On addition of hexane a yellow
solid formed which was collected by filtration and was identi-
fied as the starting complex 3. The solution was then
evaporated to dryness, and the residue was extracted with
2-propanol. On addition of a small amount of hexane a white
precipitate formed (60 mg). The analytical and IR data for
this white product [Anal. Found: C, 47.37; H, 4.32; N, 1.61.
Calcd: C, 47.85; H, 4.13; N, 1.60. IR (Nujol, cm-1): 2124 ν-
(CO), 1504, 1058, 1044, 952 (internal vibrations of C6F5), 790,
770 (“X-sensitive” mode of C6F5), 470 ν(Pd-CO)] were in
agreement with those previously reported16 for [NBu4][Pd-
(C6F5)3(CO)]. 19F NMR data (CFCl3, in (CD3)2CO), δ: -114.08
Complex 3: yield 88%; mp 203 °C dec; ΛM 199 Ω-1 cm2 mol-1
;
-
IR (Nujol, cm-1) 795, 780 (Pd-C6F5). Anal. Calcd for C68H80
N4F20O6Pd2: C, 49.7; H, 4.9; N, 3.4. Found: C, 49.1; H, 5.2;
N, 3.5. Complex 4: yield 95%; mp 230 °C dec; ΛM 212 Ω-1
cm2 mol-1; IR (Nujol, cm-1) 795, 780 (Pd-C6F5). Anal. Calcd
for C68H72N2F30O2Pd2: C, 47.2; H, 4.2; N, 1.6. Found: C, 46.7;
H, 4.5; N, 1.7. Complex 7: yield 93%; mp 183 °C dec; ΛM 227
Ω-1 cm2 mol-1; IR (Nujol, cm-1) 810, 795 (Pd-C6F5). Anal.
Calcd for C68H80N4F20O6Pt2: C, 44.9; H, 4.4; N, 3.1. Found:
C, 44.7; H, 4.8; N, 3.1. Complex 8: yield 90%; mp 221 °C dec;
ΛM 202 Ω-1 cm2 mol-1; IR (Nujol, cm-1) 810, 795 (Pd-C6F5).
Anal. Calcd for C68H72N2F30O2Pt2: C, 42.8; H, 3.8; N, 1.5.
Found: C, 42.6; H, 4.2; N, 1.5.
(m, 4Fo), -114.40 (m, 2Fo), -163.11 (t, 2Fp, J
19.75 Hz),
19.75 Hz), -165.16 (m, 4Fm), -166.55
mp
-164.62 (t, 1Fp, J
mp
(m, 2Fm). The product behaved as a 1:1 electrolyte (ΛM 90 Ω-1
cm2 mol-1) in acetone solution (c ≈ 5 × 10-4 mol dm-3).
X-r a y Str u ctu r e Deter m in a tion . A crystal suitable for
a diffraction study was grown from dichloromethane-diethyl
ether. Details of data collection and refinement are given in
Table 1.
P r ep a r a tion of Com p lexes 5 a n d 6. To a solution of
[NBu4]2[{Pt(C6F5)2(µ-OH)}2] (0.063 mmol) in toluene (10 cm3)
was added the corresponding phenol, ROH (0.126 mmol). The
resulting solution was kept under reflux with constant stirring
for 7 h. The solvent was completely evaporated under vacuum,
the residue treated with 2-propanol, and then the solid
collected by filtration and air-dried. Both complexes were
recrystallized from dichloromethane-hexane. Complex 5:
yield 60%; mp 226 °C dec; ΛM 198 Ω-1 cm2 mol-1; IR (Nujol,
cm-1) 805, 790 (Pt-C6F5). Anal. Calcd for C68H82N2F20O2Pt2:
C, 47.2; H, 4.8; N, 1.6. Found: C, 46.8; H, 5.1; N, 1.5. Complex
6: yield 70%; mp 215 °C dec; ΛM 208 Ω-1 cm2 mol-1; IR (Nujol,
cm-1) 805, 790 (Pt-C6F5). Anal. Calcd for C70H86N2F20O2Pt2:
C, 47.8; H, 4.9; N, 1.6. Found: C, 47.3; H, 5.1; N, 1.6.
Resu lts a n d Discu ssion
The ready reactivity of [{MR2(µ-OH)}2]2--type com-
plexes (M ) Ni, Pd, Pt; R ) pentahalophenyl) toward
protic electrophiles is in agreement with the high-field
proton resonance of the OH bridges,17 and they have
been used for the synthesis of complexes of the types
[{MR2(µ-L-L)}2]2- (L-L ) exobidentate ligand),14,15,18
[{MR2(L-L)]- (L-L ) endobidentate ligand),13,19 or [{MR2-
(µ-X)}2]2- (X ) monodentate ligand).20 The hydroxo
complexes [NBu4]2[{M(C6F5)2(µ-OH)}2] (M ) Pd or Pt)
react with 2 molar equiv of phenols to give the corre-
sponding anionic bis(µ-aryloxo) complexes 1-8 shown
in Scheme 1, which are isolated as the tetrabutylam-
monium salts. The reaction occurs smoothly at room
temperature for complexes 1-4, 7, and 8, but reflux
temperature is required for the preparation of 5 and 6.
All the isolated complexes show the characteristic
infrared absorptions of the pentafluorophenyl group21
P r ep a r a tion of Com p lexes 9-12. To a solution of the
corresponding bis(µ-aryloxo) complex 3, 4, 7, or 8 (0.055 mmol)
in dichloromethane (6 cm3) was added triphenylphosphine
(0.110 mmol). After being stirred for 1 h at room temperature,
the solution was concentrated to dryness; the residue was
treated with hexane (9, 11) or ether/hexane (10, 12), and the
complexes were collected by filtration and air-dried. Complex
9: yield 77%; mp 180 °C dec; ΛM 86 Ω-1 cm2 mol-1; IR (Nujol,
cm-1) 785, 765 (Pd-C6F5). Anal. Calcd for C52H55N2F10O3-
PPd: C, 57.7; H, 5.1; N, 2.6. Found: C, 57.7; H, 5.4; N, 2.6.
Complex 10: yield 95%; mp 198 °C dec; ΛM 95 Ω-1 cm2 mol-1
;
IR (Nujol, cm-1) 785, 765 (Pd-C6F5). Anal. Calcd for C52H51
-
(16) Uso´n, R.; Fornie´s, J .; Toma´s, M.; Casas, J . M.; Navarro, R. J .
Chem. Soc., Dalton Trans. 1989, 169.
(17) Lo´pez, G.; Garc´ıa, G.; Ruiz, J .; Sa´nchez, G.; Garc´ıa, J .; Vicente,
C. J . Chem. Soc., Chem. Commun. 1989, 1045.
NF15OPPd: C, 55.4; H, 4.6; N, 1.2. Found: C, 54.8; H, 4.9; N,
1.3. Complex 11: yield 65%; mp 238 °C dec; ΛM 96 Ω-1 cm2
mol-1; IR (Nujol, cm-1) 880, 775 (Pt-C6F5). Anal. Calcd for
C52H55N2F10O3PPt: C, 53.3; H, 4.7; N, 2.4. Found: C, 52.9;
H, 5.1; N, 2.3. Complex 12: yield 65%; mp 226°C dec; ΛM 102
Ω-1 cm2 mol-1; IR (Nujol, cm-1) 800, 775 (Pt-C6F5). Anal.
Calcd for C52H51NF15OPPt: C, 51.3; H, 4.2; N, 1.2. Found: C,
51.8; H, 4.6; N, 1.1.
(18) (a) Lo´pez, G.; Garc´ıa, G.; Sa´nchez, G.; Santana, M. D.; Ruiz,
J .; Garc´ıa, J . Inorg. Chim. Acta 1991, 188, 195. (b) Lo´pez, G.; Ruiz, J .;
Garc´ıa, G.; Mart´ı, J . M.; Sa´nchez, G.; Garc´ıa, J . J . Organomet. Chem.
1991, 412, 435. (c) Lo´pez, G.; Sa´nchez, G.; Garc´ıa, G.; Ruiz, J .; Garc´ıa,
J .; Mart´ınez-Ripoll, M.; Vegas, A.; Hermoso, J . A. Angew. Chem., Int.
Ed. Engl. 1991, 30, 716. (d) Lo´pez, G.; Garc´ıa, G.; Sa´nchez, G.; Garc´ıa,
J .; Ruiz, J .; Hermoso, J . A.; Vegas, A.; Mart´ınez-Ripoll, M. Inorg. Chem.
1992, 31, 1518.
(19) (a) Lo´pez, G.; Sa´nchez, G.; Garc´ıa, G.; Garc´ıa, J .; Sanmart´ın,
A.; Santana, M. D. Polyhedron 1991, 10, 2821. (b) Lo´pez, G.; Sa´nchez,
G.; Garc´ıa, G.; Garc´ıa, J .; Mart´ınez, A. J . Organomet. Chem. 1992,
435, 193. (c) Lo´pez, G.; Ruiz, J .; Garc´ıa, G.; Vicente, C.; Mart´ı, J . M.;
Rodr´ıguez, V. J . Organomet. Chem. 1992, 436, 121. (d) Lo´pez, G.; Ruiz,
J .; Garc´ıa, G.; Vicente, C.; Mart´ı, J . M.; Hermoso, J . A.; Vegas, A.;
Mart´ınez-Ripoll, M. J . Chem. Soc., Dalton Trans. 1992, 53. (e) Sa´nchez,
G.; Mun˜oz, J . A.; Vidal, M. J .; Garc´ıa, G.; Lo´pez, G. J . Organomet.
Chem. 1993, 463, 239.
P r ep a r a tion of Com p lexes 13 a n d 14. Through a dichlo-
romethane solution (15 cm3) of the corresponding bis(µ-aryloxo)
complex 7 or 8 (0.055 mmol) at room temperature was passed
CO for 20 min. The mixture was evaporated to dryness under
vacuum, the residue treated with hexane, and the solid
collected by filtration. Crystals were obtained by recrystalli-
zation from dichloromethane-hexane. Complex 13: yield 95%;
mp 232 °C dec; ΛM 89 Ω-1 cm2 mol-1; IR (Nujol, cm-1): 2090
(ν(CO)), 810, 795 (Pt-C6F5). Anal. Calcd for C35H40N2F10O4-
Pt: C, 44.8; H, 4.3; N, 3.0. Found: C, 44.8; H, 4.6; N, 3.0.
(20) (a) Ruiz, J .; Mart´ınez, M. T.; Vicente, C.; Garc´ıa, G.; Lo´pez, G.;
Chaloner, P. A.; Hitchcock, P. B. Organometallics 1993, 12, 4321. (b)
Sa´nchez, G.; Ruiz, F.; Santana, M. D.; Garc´ıa, G.; Lo´pez, G.; Hermoso,
J . A.; Mart´ınez-Ripoll, M. J . Chem. Soc., Dalton Trans. 1994, 19.
(21) Deacon, G. B.; Green, J . H. S. Spectrochim. Acta 1968, 24, 1125.
Complex 14: yield 88%; mp 244 °C dec; ΛM 93 Ω-1 cm2 mol-1
IR (Nujol, cm-1): 2085 (ν(CO)), 810, 795 (Pt-C6F5). Anal.
;

1664 Organometallics, Vol. 15, No. 6, 1996
Ruiz et al.
Ta ble 1. Cr ysta l Str u ctu r e Deter m in a tion Deta ils
Sch em e 1
Crystal Data
formula
fw
C35H40F10N2O4Pt
937.8
cryst syst
space group
cell dimens
a (Å)
b (Å)
c (Å)
monoclinic
P21/c (No. 14)
8.771(1)
21.766(3)
20.249(5)
90
90.97(2)
90
3865(1)
4
1.61
R (deg)
â (deg)
γ (deg)
cell vol (Å3)
Z
D
calc (g cm-3
F(000)
)
1856
monochromated Mo KR
radiation
λ (Å)
0.710 73
37.5
µ (cm-1
)
Data Collection
cryst size (mm)
diffractometer
0.25 × 0.25 × 0.2
Enraf-Nonius CAD4
25; 7, 10
no. of reflns for calculating
cell; θmin, θmax (deg)
scan mode for data collcn
data refln ranges,
θ min and max (deg)
tot. no. of reflns measd
no. of unique reflns
Rint
θ-2θ
h, 0 f 10; k, 0 f 25;
l, -24 f 24, 2 f 25
7459
6997
0.01
no. of significant reflns,
4673
|F2| > 2σ(F2)a
max change in std reflns (%) -0.9
decay corr
The reaction of the bis(µ-aryloxo) complexes 3, 4, 7,
and 8 with PPh3 in 1:2 molar ratio leads to the
formation of the monomeric aryloxo complexes [M(C6F5)2-
(OR)(PPh3)] (9-12) (Scheme 1). Although the reaction
of 1 with 2 molar equiv of PPh3 was tried, the expected
phenoxo-phosphine compound was not formed; instead
a mixture of the previously known24 [Pd(C6F5)2(PPh3)2]
and the starting complex 1 was obtained.
no
max, min abs corr
1.00, 0.86 from ψ scans
Structure Solution and Refinement
non-H atoms located by heavy atom methods, SHELXS-86
refinement by
full-matrix least squares,
non-H atoms anisotropic,
Enraf-Nonius MolEN programs
fixed calcd posns, Uiso ) 1.3Ueq
for parent atom
H atoms
Complexes 9-12 behave as 1:1 electrolytes23 in
acetone solution, and the cis arrangement of the C6F5
groups is supported by the split band observed in their
IR spectra at ca. 800 cm-1, due to the “X-sensitive”
mode. The 1H, 19F, and 31P NMR data for these
complexes are listed in Table 3. The 19F NMR spectra
indicate the presence of two different pentafluorophenyl
groups.
R
R ′
S
0.035
0.036
1.1
469
4673
0.03
+0.39, -0.14
no. of variables
no. of obsd reflcns
max (∆/σ)
max, min (∆/F) (e Å-3
)
σ(F2) ) {σ2(I) + (0.04I)2}1/2/Lp, w ) σ-2(F), ∑w(|Fo| - |Fc|)2
a
minimized.
The reaction of the bis(µ-aryloxo)platinum complexes
7 and 8 with CO (1 atm) at room temperature, in
dichloromethane solution, yields the monocarbonyl com-
plexes 13 and 14 shown in Scheme 1. A wide range of
platinum(II) carbonyl derivatives are known.25 Com-
plexes 13 and 14 are air- and moisture-stable solids
which in their IR spectra show a strong absorption at
ca. 2090 cm-1 due to ν(CO) of a terminal carbonyl ligand.
The previously reported25 cis-[Pt(C6F5)2X(CO)]- com-
pounds (X ) Cl, Br, I) give a similar band at 2090-
2080 cm-1. The 19F NMR spectra show two nonequiv-
alent C6F5 groups corroborating the cis arrangement of
these groups, one trans to CO and one trans to OR; this
is also supported by the split band observed at ca. 800
cm-1. In the 19F NMR spectrum the resonance signals
at lower field are assigned to the C6F5 group trans to
CO because of the greater π-acceptor character of the
at ca. 1630 m, 1495 vs, 1050 s, 950 vs, and 800 cm-1
.
The absorption at 800 cm-1, which is related to the so-
called “X-sensitive mode” in C6F5X (X ) Cl, Br, I)
molecules, is observed as a split band suggesting that
the M(C6F5)2 moiety has cis geometry.22 Measurements
of the molar conductivity in acetone indicate that
complexes 1-8 behave as 2:1 electrolytes.23 The 1H and
19F NMR spectra (Table 2) are consistent with the
proposed formulae. The 19F NMR spectra show the
presence of four equivalent freely rotating C6F5 rings
giving three resonances with relative intensities of 8:4:8
due to the ortho-, para-, and meta-F atoms, respectively.
The spectra of complexes 4 and 8 show three additional
signals (relative intensities of 4:4:2) from the two
µ-C6F5O groups. As expected, the ortho-F signals of
complexes 5-8 are flanked by the satellites due to
coupling to 195Pt.
(24) Uso´n, R.; Fornie´s, J .; Espinet, P.; Mart´ınez, F.; Toma´s, M. J .
Chem. Soc., Dalton Trans. 1981, 463.
(25) Uso´n, R.; Fornie´s, J .; Toma´s, M.; Menjo´n, B. Organometallics
1986, 5, 1581.
(22) Maslowsky, E. Vibrational Spectra of Organometallic Com-
pounds; Wiley: New York, 1977; p 437.
(23) Geary, W. J . Coord. Chem. Rev. 1971, 7, 8.

Bis(µ-aryloxo) Complexes of Pd and Pt
Organometallics, Vol. 15, No. 6, 1996 1665
Ta ble 2. NMR Sp ectr oscop ic Da ta a ,b (J in Hz) for
Com p lexes 1-8
com-
plex
1Hc
19F
1
6.48 (m, 8 H, Ho + Hm
6.06 (t, 2 H, Hp, J 7.2)
)
-113.6 (d, 8 Fo, J 29.1)
-166.6 (t, 4 Fp, J 19.8)
-167.6 (m, 8 Fm
)
2
3
4
6.42 (d, 4 H, Ho, J 8.3)
6.24 (d, 4 H, Hm, J 8.3)
1.87 (s, 6 H, CH3)
7.54 (d, 4 H, Ho, J 9.0)
6.53 (d, 4 H, Hm, J 9.0)
-113.5 (d, 8 Fo, J 30.5)
-166.8 (t, 4 Fp, J 21.2)
-167.7 (m, 8 Fm
)
-114.5 (d, 8 Fo, J 27.4)
-164.5 (t, 4 Fp, J 19.8)
-166.6 (m, 8 Fm
)
-114.8 (d, 8 Fo, J 26.0)
-156.8 (dd, 4 Fo, C6F5O,
J om 20.0, J op 6.5)
-164.6 (t, 4 Fp, J 19.8)
-166.8 (m, 8 Fm
)
-171.8 (dd, 4 Fm, C6F5O,
J om ) J mp 20.0)
-178.6 (tt, 2 Fp, C6F5O,
J mp 20.0, J op 6.5)
5
6
7
8
6.71 (d, 4 H, Ho, J 7.5)
-117.8 (d, 8 Fo, J 26.0,
J PtF 536.0)
6.54 (dd, 4 H, Hm, J ) J ′ 7.5) -168.7 (to, 4 Fp, J 19.8)
6.19 (t, 2 H, Hp, J 7.5)
6.59 (d, 4 H, Ho, J 8.3)
-169.2 (m, 8 Fm)
-117.6 (d, 8 Fo, J 26.0,
J PtF 531.1)
6.33 (d, 4 H, Hm, J 8.3)
1.93 (s, 6 H, CH3)
7.63 (d, 4 H, Ho, J 9.0)
-168.8 (to, 4 Fp, J 19.8)
-169.2 (m, 8 Fm
)
F igu r e 1. Molecular structure of [Pt(C6F5)2(OC6H4NO2-
p)(CO)]-. The ORTEP diagram shows the non-H atoms as
20% thermal vibration ellipsoids.
-118.4 (d, 8 Fo, J 26.0,
J PtF 527.8)
6.78 (d, 4 H, Hm, J 9.0)
-166.5 (to, 4 Fp, J 18.3)
-168.0 (m, 8 Fm
)
-118.9 (d, 8 Fo, J 24.3,
the rhodium complex, the Pt-C6F5 bond trans to the
carbonyl (2.040(5) Å) is longer than than that trans to
the aryloxy group (2.006(5) Å), in accord with the
expected trans-influence, but both are within the normal
range for (pentafluorophenyl)platinum derivatives.
Mononuclear alkoxy- and (aryloxy)platinum complexes
are rare, and to the best of our knowledge, this is the
first to be characterized in a diffraction study.
J PtF 537.3)
o
-154.9 (d, 4 Fo, C6F5O,
J om 22.9)
-166.4 (t, 4 Fp, J 19.8)
-168.2 (m, 8 Fm
)
-171.0 (dd, 4 Fm, C6F5O,
J om ) J mp 22.9)
-175.4 (t, 2 Fp, C6F5O,
J mp 22.9)
The chemical behavior of the palladium complex 3
toward CO is quite different from that above described
for the platinum compounds. When CO (1 atm) was
passed through a dichloromethane solution of 3, a
mixture of palladium complexes, metallic palladium,
and p-nitrophenol was obtained. The 1H and 19F spectra
gave no evidence of the formation of C6F5CO2C6H4NO2-
p, the expected product from the insertion of carbon
monoxide into the Pd-C6F5 or Pd-OC6H4NO2-p bonds.28
However the formation of p-nitrophenol requires the
presence of water in the reaction mixture. Despite
precautions taken to avoid water, adventitious water
was always present and the experiment was therefore
carried out with controlled amounts of water. In a
typical experiment, CO was passed through a dichlo-
romethane solution containing a 1:2 molar mixture of
the bis(µ-aryloxo) complex 3 and water, respectively,
until the solvent was completely evaporated. The crude
material was then dissolved in (CD3)2CO to obtain the
1H and the19F NMR spectra which showed that 50% of
complex 3 had been transformed. Figure 2 shows the
a
Chemical shifts in ppm from TMS (1H) or from CFCl3 19F).
(
Abbreviations: s, singlet; d, doublet; t, triplet; m, multiplet; dd,
doublet of doublets; tt, triplet of triplets. In (CD3)2CO. c Addi-
b
tional peaks of [NBu4]+ are found at δ ca. 3.43 (t, NCH2), 1.80 (m,
NCH2CH2), 1.40 (m, CH2CH3), and 0.95 (t, CH3), the relative
intensities being 16:16:16:24, respectively.
CO ligand, and this is in agreement with the higher
value of the coupling constant J (PtFo) which should
correspond to the C6F5 group trans to the ligand with
the lower trans influence.
The structure of 14 in the solid state has been
determined by a single-crystal X-ray diffraction study
Figure 1). The coordination about platinum is ap-
proximately square planar with small deviations which
might be attributed to the low steric demand of the
carbonyl ligand. There have been two previous reports
of structures containing the {Pd(C6F5)2(CO)} moiety.
The Pt-CO bond length is similar to those found for
cis-[Pt(C6F5)2(CO){SC(dS)P(C6H11)3}] (1.910(9) Å)26 and
[Pt(C6F5)2(CO)}{Rh (CO)2Cp}] (1.860(9) Å).27 However,
the carbon-oxygen bond length is shorter (1.115(8) Å
against 1.128(10) and 1.162(10) Å for the betaine and
the rhodium derivatives, respectively), which is slightly
surprising, since the formal negative charge might have
been expected to lead to greater back-bonding. As in
(28) The reaction of CO with alkylpalladium aryloxides has previ-
ously been studied. CO inserts into the alkyl-palladium bonds to give
acylmetal aryloxides which in turn undergo reductive elimination with
formation of metal and the corresponding aryl ester in high yield:
Komiya, S.; Akai, Y.; Tanaka, K.; Yamamoto, T.; Yamamoto, A.
Organometallics 1985, 4, 1130. However in the reaction of CO with
the phenoxide complexes cis-[PdMe(OPh)(PMe3)2] and [PdMe(OPh)-
(dppe)] insertion of CO into the Pd-OPh bond was suggested, and the
resulting methylpalladium complex having the phenoxycarbonyl ligand
reductively eliminates the ester in low yield.9
(26) Uso´n, R.; Fornie´s, J .; Uso´n, M. A.; Yagu¨e, J . F.; J ones, P. G.;
Meyer-Ba¨se, K. J . Chem. Soc., Dalton Trans. 1986, 947.
(27) Uso´n, R.; Fornie´s, J .; Espinet, P.; Fortun˜o, C.; Toma´s, M.; Welch,
A. J . J . Chem. Soc., Dalton Trans. 1988, 3005.

1666 Organometallics, Vol. 15, No. 6, 1996
Ta ble 3. NMR Sp ectr oscop ic Da ta a ,b (J in Hz) for Com p lexes 9-14
Ruiz et al.
complex
1Hc
19F
31P
9
7.60 (m, 8 H, Ho PPh3 + Ho ArO)
7.33 (m, 9 H, Hm + Hp PPh3)
6.49 (d, 2 H, Hm ArO, J 9.3)
-114.2 (m, 4 Fo)
-164.3 (t, 1 Fp, J 19.8)
-165.5 (m, 2 Fm
-165.7 (t, 1 Fp, J 19.2)
20.3 (s)
)
-166.1 (m, 2 Fm
)
10
7.81 (m, 6 H, Ho PPh3)
7.36 (m, 9 H, Hm + Hp PPh3)
-113.6 (d, 2 Fo, J 27.7)
-114.3 (br, 2 Fo)
-162.7 (m, 2 Fo, C6F5O)
-164.7 (t, 1 Fp, J 19.8)
20.6 (s)
-165.8 (m, 2 Fm
)
-166.3 (m, 1 Fp + 2 Fm
)
-172.8 (dd, 2 Fm, C6F5O, J ) J ′ 21.4)
-186.1 (m, 1 Fp, C6F5O)
11
12
7.61 (m, 8 H, Ho PPh3 + Ho ArO)
7.32 (m, 9 H, Hm + Hp PPh3)
6.63 (d, 2 H, Hm ArO, J 9.3)
-117.3 (d, 2 Fo, J 25.4, J PtF 497.8)
-117.7 (dd, 2 Fo, J om )J PF 22.0, J PtF 338.1)
-165.0 (t, 1 Fp, J 19.8)
19.1 (s, J PPt 2671)
20.3 (s, J PPt 2748)
-166.2 (m, 2 Fm
)
-167.7 (m, 2 Fm +1Fp)
7.82 (m, 6 H, Ho PPh3)
7.36 (m, 9 H, Hm + Hp PPh3)
-116.7 (d, 2 Fo, J 26.0, J PtF 500.6)
-117.5 (dd, 2 Fo, J om ) J PF 21.4, J PtF 369.7)
-161.5 (m, 2 Fo, C6F5O)
-165.5 (t, 1 Fp, J 20.0)
-166.7 (m, 2 Fm
)
-168.0 (m, 2 Fm + 1 Fp)
-172.2 (dd, 2 Fm, C6F5O, J om ) J mp 21.2)
-183.9 (m, 1 Fp, C6F5O)
13
14
7.94 (d, 2 H, Ho, J 9.3)
6.89 (d, 2 H, Hm, J 9.3)
-118.2 (d, 2 Fo, J 23.4, J PtF 381.0)
-119.5 (d, 2 Fo, J 24.3, J PtF 338.6)
-162.2 (t, 1 Fp, J 19.8)
-162.9 (m, 1 Fp)
-165.6 (m, 4 Fm
)
-117.7 (d, 2 Fo, J 24.3, J PtF 431.8)
-119.6 (d, 2 Fo, J 24.8, J PtF 366.9)
-162.5 (m, 2 Fo (C6F5O) + 1 Fp (C6F5))
-163.1 (t, 1 Fp, J 18.3)
-165.8 (m, 4 Fm
)
-170.5 (dd, 2 Fm, C6F5O, J om ) J mp 21.2)
-180.8 (m, 1 Fp, C6F5O)
a
b
Chemical shifts from TMS (1H), from CFCl3 (19F), or from H3PO4 (31P). In (CD3)2CO. c Additional peaks of [NBu4]+ are found at δ ca.
3.43 (t, NCH3), 1.80 (m, NCH2CH2), 1.40 (m, CH2CH3), and 0.95 (t, CH3), the relative intensities being 8:8:8:12, respectively.
1
low-field region of the H NMR spectrum. It consists
of four pairs of doublets at δ 8.04 and 6.85, 7.81 and
6.82, 7.78 and 6.92, and 7.56 and 6.54 with approximate
relative intensities of 2:1:1:4. By comparison with
genuine samples, the first and fourth pairs of doublets
(a and d) could unambiguously be assigned to p-O2-
NC6H4OH and the unreacted complex 3, respectively.
The second and third pairs (b and c) could not be
confidently assigned, but their spectral positions strongly
suggest the presence of two additional palladium species
containing Pd-OC6H4NO2 bonds (the monomeric [cis-
Pt(C6F5)2(OC6H4NO2-p)(CO)]- gives two doublets at δ
7.94 and 6.89). Scheme 2 shows the suggested mech-
anism to explain the experimental results. The cleavage
of the aryloxo bridges in complex 3 by CO should
produce [Pd(C6F5)2(OR)(CO)]- (R ) OC6H4NO2-p) in a
similar manner as that described above for platinum.
Under rigourously anhydrous conditions the isolation
of [Pd(C6F5)2(OR)(CO)]- should be difficult because of
the well-known reluctance of palladium to be involved
in bonding to CO.29 The presence of this complex is
supported by two 19F-NMR signals with relative inten-
sities of 1:1 in the o-fluorine region at δ -115.4 and
-116.0, respectively, and a weak CO stretching band
assigned to this species by analogy with the correspond-
ing platinum complex. The next step involves the
nucleophilic attack of coordinated CO by an OH- ion,30
forming a -CO(OH) ligand, which subsequently loses
CO2. p-Nitrophenol is also formed in this step. During
the decomposition of the undetected hydroxycarbonyl
complex to give metallic palladium and carbon dioxide,
in the presence of unreacted [Pd(C6F5)2(OR)(CO)]-, a
C6F5 transfer reaction occurs to form [Pd(C6F5)3(CO)]-
(spectroscopic data in Experimental Section), as shown
in Scheme 2. Any comment on this C6F5 transfer
reaction would be speculative, but a palladium complex
containing both terminal and bridging C6F5 is known.31
1
Since the H NMR spectrum gives no indication of the
presence of free RO-, this group should be trapped by
some palladium complex present in the solution to form
a new (aryloxo)palladium complex. Thus the formation
of [Pd(C6F5)2(OR)2]2- by reaction between [Pd(C6F5)2-
(OR)(CO)]- and RO- is suggested, which is supported
by the observation of the pair b of 1H-NMR signals
(Figure 2). Further evidence is provided by the 19F
NMR spectrum which shows a single resonance in the
(30) This is the well-known oxidation reaction of the CO ligand in
the presence of the strongly basic ligand OH-, the net outcome being
the reduction of the metal center; see, for example, Shriver, D. F.;
Atkins, P. W.; Langford, C. H. Inorganic Chemistry, 2nd ed.; Oxford:
Oxford, U.K., 1994; p 717.
at 2020 cm-1. The pair c of H-NMR signals can be
1
(29) The low stability of the palladium complexes is not due to an
intrinsically thermodynamic instability but to the lability of the Pd-
(II)-CO bond: Dell’Amico, D. B.; Calderazzo, F.; Zandona, N. Inorg.
Chem. 1984, 23, 137.
(31) The synthesis of [(C6F5)2Pd(µ-C6F5)2Pd (C6F5)2]2- was previously
reported.16 This binuclear complex reacts with CO yielding [Pd-
(C6F5)3(CO)]-.

Bis(µ-aryloxo) Complexes of Pd and Pt
Organometallics, Vol. 15, No. 6, 1996 1667
Ta ble 4. F r a ction a l Atom ic Coor d in a tes a n d
Equ iva len t Isotr op ic Th er m a l P a r a m eter s (Å2)
x
y
z
Ueq
Pt
F1
F2
F3
F4
F5
F6
F7
F8
F9
F10
O1
O2
O3
O4
N1
N2
C1
C2
C3
C4
C5
C6
C7
C8
0.07648(2)
0.1668(5)
0.2331(6)
0.2277(6)
0.1498(6)
0.11529(1)
-0.0255(2)
-0.0950(2)
-0.0457(2)
0.0733(3)
0.1429(2)
0.0189(2)
-0.0433(2)
-0.0315(3)
0.0432(2)
0.1048(2)
0.1728(2)
0.1414(2)
0.2202(3)
0.1825(2)
0.1799(3)
0.3047(2)
0.0618(3)
0.0004(3)
-0.0354(3)
-0.0113(3)
0.0483(3)
0.0834(3)
0.1732(3)
0.1282(3)
0.1306(3)
0.1776(3)
0.2233(3)
0.2211(3)
0.0663(3)
0.0281(3)
-0.0050(4)
0.0002(4)
0.0379(4)
0.0696(3)
0.1583(3)
0.2512(3)
0.2432(3)
0.1941(3)
0.1769(4)
0.3655(3)
0.3805(3)
0.4403(5)
0.4411(7)
0.2991(3)
0.2420(3)
0.2471(4)
0.1891(4)
0.3020(3)
0.3463(3)
0.3379(3)
0.3768(4)
0.23180(1)
0.2196(2)
0.1162(3)
-0.0068(2)
-0.0244(2)
0.0786(2)
0.3432(2)
0.3673(3)
0.2875(3)
0.1801(3)
0.1547(2)
0.3093(2)
0.5687(2)
0.5939(2)
0.2023(3)
0.5552(2)
0.1635(2)
0.1534(3)
0.1590(3)
0.1073(4)
0.0455(4)
0.0358(3)
0.0904(3)
0.3664(3)
0.3869(3)
0.4481(3)
0.4898(3)
0.4717(3)
0.4112(3)
0.2485(3)
0.3014(3)
0.3152(4)
0.2755(5)
0.2222(4)
0.2090(3)
0.2140(3)
0.1152(3)
0.0788(3)
0.0262(3)
-0.0030(4)
0.1288(3)
0.0703(4)
0.0376(5)
-0.0008(7)
0.2166(3)
0.2577(3)
0.3184(4)
0.3604(4)
0.1920(3)
0.2465(3)
0.2689(3)
0.3268(4)
0.057(1)
0.096(3)
0.149(4)
0.164(4)
0.144(4)
0.103(3)
0.135(3)
0.192(4)
0.206(5)
0.174(4)
0.106(3)
0.073(2)
0.122(4)
0.131(4)
0.110(3)
0.098(4)
0.061(3)
0.058(3)
0.075(4)
0.096(5)
0.102(5)
0.093(5)
0.074(4)
0.065(3)
0.070(4)
0.077(4)
0.074(4)
0.080(4)
0.076(4)
0.059(3)
0.087(4)
0.114(5)
0.128(6)
0.108(5)
0.078(4)
0.074(4)
0.065(3)
0.076(4)
0.094(5)
0.118(6)
0.077(4)
0.111(6)
0.171(8)
0.329(16)
0.072(4)
0.076(4)
0.099(5)
0.129(6)
0.066(4)
0.080(4)
0.092(5)
0.126(6)
0.0784(5)
-0.0118(5)
-0.2634(7)
-0.5130(5)
-0.4978(5)
-0.2445(4)
0.0222(4)
0.4046(6)
0.2682(6)
0.3663(5)
0.3076(6)
-0.1861(5)
0.1176(6)
0.1572(7)
0.1943(8)
0.1929(9)
0.1524(8)
0.1162(7)
0.0933(6)
0.1985(7)
0.2679(7)
0.2352(7)
0.1340(7)
C9
C10
C11
C12
C13
C14
C15
C16
C17
C18
C19
C20
C21
C22
C23
C24
C25
C26
C27
C28
C29
C30
C31
C32
C33
C34
C35
F igu r e 2. (A) Partial 1H NMR spectrum of the crude
material obtained from the reaction between complex 3 and
CO in the presence of water (see text). (B) Partial 1H NMR
spectrum of the crude material after elimination of metallic
palladium and partial precipitation with hexane. This
spectrum shows that the pseudotriplet at ca. δ 7.8 and the
multiplet at δ 7.0-6.8 in (A) are related to two and three
different complexes, respectively.
0.0651(7)
-0.1174(6)
-0.1322(7)
-0.2602(9)
-0.3829(8)
-0.3771(7)
-0.2450(6)
0.2580(7)
-0.1976(6)
-0.3491(7)
-0.3380(8)
-0.4899(9)
-0.2153(7)
-0.1185(10)
-0.1691(14)
-0.2709(21)
-0.3036(6)
-0.2953(7)
-0.3915(8)
-0.3888(10)
-0.0250(6)
0.0147(7)
Sch em e 2
0.1794(7)
0.2204(10)
a
Ueq is defined as one-third of the trace of the orthogonalized
Uij tensor.
Ta ble 5. Selected In tr a m olecu la r Dista n ces (Å)
a n d An gles (d eg) for [P t(C6F 5)2(OC6H4NO2-p)(CO)]-
w ith Estim a ted Sta n d a r d Devia tion s in
P a r en th eses
Bonds
Pt-O1
Pt-C13
O4-C19
2.070(4)
2.040(5)
1.115(8)
Pt-C1
Pt-C19
2.006(5)
1.887(6)
Angles
O1-Pt-C1
O1-Pt-C19
C1-Pt-C19
Pt-C19-O4
176.3(2)
92.9(2)
88.5(2)
178.0(6)
O1-Pt-C13
C1-Pt-C13
C13-Pt-C19
89.3(2)
89.4(2)
177.8(2)
o-fluorine region at δ ca. -114.4 ppm (this signal, which
is partially overlapped with the signal provided by the
C6F5 group trans to CO in [Pd(C6F5)3(CO)]-, could be
discernible in the spectrum only when it was obtained
at low temperature in d6-acetone; at room temperature
the signal was completely masked by the 19F peak from
the C6F5 group trans to CO in [Pd(C6F5)3(CO)]-) and two
additional peaks at δ -166.2 and -167.4 corresponding
to the p- and m-fluorine atoms, respectively. The
correctness of this assignment was confirmed by com-

1668 Organometallics, Vol. 15, No. 6, 1996
Ruiz et al.
parison with an authentic sample of [NBu4]2[Pd(C6F5)2-
A 1:1 ratio should lead to the formation of [Pd(C6-
F5)3(CO)]- and [Pd(C6F5)2(OR)2]2- in 2:1 ratio, respec-
tively, and the concomitant liberation of 2 mol of C6F5H;
however, only traces of C6F5H are observed in the 19F
NMR spectrum. The chemical behavior of complex 4
toward carbon monoxide was similar to that just de-
scribed for complex 3.
1
(OR)2] prepared by a different method.32 The H NMR
spectrum, taken in conjunction with the 19F NMR
spectrum, demonstrated that the amounts of [Pd(C6-
F5)3(CO)]-, p-O2NC6H4OH, and [Pd(C6F5)2(OR)2]2- are
in the molar ratio 4:4:1, respectively, as required by the
proposed reaction pathway of Scheme 2. Furthermore
the experimental Pd/CO2 molar ratio is 1:1 (carbon
dioxide was controlled as BaCO3 by bubbling the
released gas through baryta water). It is worth noting
that the C6F5 transfer reaction occurs with the reactants
(the hydroxycarbonyl complex and [Pd(C6F5)2(OR)-
(CO)]-) in the 1:2 mol ratio which leads to the actual
4:4:1 ratio above mentioned for the reaction products.
Ack n ow led gm en t. Financial support of this work
by the DGICYT (Project PB94-1157), Spain, is acknowl-
edged. V.R. thanks The Direccio´n Regional de Educa-
cio´n y Universidad de Murcia, Murcia, Spain, for a
research grant.
Su p p or tin g In for m a tion Ava ila ble: Tables of intramo-
lecular distances and angles, hydrogen atom coordinates,
anisotropic temperature factors in the form exp[-2π2(U11h2a*2
(32) [NBu4]2[{Pd(C6F5)2(µ-OH)}2] was reacted with p-O2NC6H4OH
and [NBu4]OH in the molar ratio 1:4:2, respectively, in acetone; after
being stirred for ca. 1 h, the solution was evaporated to dryness and
the residue was treated with MeOH-H2O and filtered off to yield a
yellow solid which was identified as [NBu4]2[Pd(C6F5)2(OC6H4NO2-p)2].
Its 1H and 19F NMR data were coincident with those given in the text.
+ U22k2b*2 + U33l2c*2 + 2U12hka*b* + 2U13hla*c* + 2U23
-
klb*c*)], and least squares planes for 13 (8 pages). Ordering
information is given on any current masthead page.
OM950409A