Strong activation of the double bond in (PPh2)2C=CH2. Novel synthesis of gold(III) methanide complexes by michael addition reactions

Article abstract of DOI:10.1021/om9609832

Treatment of [Au(μ-Cl)(C₆F₅)²]² with vinylidenebis(diphenylphosphine), (PPh₂)₂C=CH₂, leads to the complex [Au(C₆F₅)₂Cl{PPh₂C(=CH

Full text of DOI:10.1021/om9609832

1130
Organometallics 1997, 16, 1130-1136
Str on g Activa tion of th e Dou ble Bon d in (P P h 2)2CdCH2.
Novel Syn th esis of Gold (III) Meth a n id e Com p lexes by
Mich a el Ad d ition Rea ction s
Eduardo J . Ferna´ndez,† M. Concepcio´n Gimeno,‡ Peter G. J ones,§
Antonio Laguna,*,‡ and Elena Olmos†
Departamento de Quı´mica, Universidad de la Rioja, Obispo Bustamante 3,
E-26001 Logron˜o, Spain, Departamento de Quı´mica Inorga´nica, Instituto de Ciencia de
Materiales de Arago´n, Universidad de Zaragoza-C.S.I.C., E-50009 Zaragoza, Spain, and
Institut fu¨r Anorganische und Analystische Chemie der Technischen Universita¨t,
Postfach 3329, D-38023 Braunschweig, Germany
Received November 21, 1996X
Treatment of [Au(µ-Cl)(C6F5)2]2 with vinylidenebis(diphenylphosphine), (PPh2)2CdCH2,
leads to the complex [Au(C6F5)2Cl{PPh2C(dCH2)PPh2}]. The coordination of the diphosphine
to a gold(III) center strongly activates the carbon-carbon double bond, and this complex,
therefore, undergoes Michael-type additions with several carbon-, sulfur-, or oxygen-based
nucleophiles. The complexes [Au(C6F5)2{(PPh2)2CCH2SPh}], [Au(C6F5)2{(PPh2)2CCH2S2-
CNEt2}], and [{Au(C6F5)2{(PPh2)2CCH2}}2O] have been structurally characterized by X-ray
diffraction analysis. They show that the addition has taken place at the terminal carbon
atom of the double bond, giving methanide-type complexes. Furthermore, the displacement
i
of the ether molecules in [Au(C6F5)2(OR2)2]ClO4 (R ) Et, Pr) by the diphosphine leads, in a
one pot synthesis, to the complexes [Au(C6F5)2{(PPh2)2CHCH2OR}]ClO4 as a consequence
of ether cleavage by water.
In tr od u ction
quaternization of vinylidenebis(diphenylphosphine) gave
an unexpected secondary reaction of cycloaddition at the
terminal carbon atom of the double bond, thus, affording
a cyclic methanide derivative.10,11
Although the double bond in uncoordinated vinyl-
idenebis(diphenylphosphine) is not normally susceptible
to nucleophilic attack, it has been shown that complex-
ation to a metal center activates the double bond in such
a manner that various nucleophiles can be added by
Michael-type reactions.1-9 In these processes, the nu-
cleophile HNu is added to complexes [M]-(PPh2)2CdCH2
to give the products [M]-(PPh2)2CH-CH2Nu. However,
reactions in which the addition takes place only at the
terminal carbon atom of the double bond, thus affording
species of the type [M]-(PPh2)2C-CH2Nu in which the
central carbon atom can be regarded as a methanide
carbon, are unknown. Furthermore, these species can
be regarded as intermediates in the addition reactions
to the double bond. This method would represent a
novel synthesis of gold methanide complexes. Only one
such example has been reported in the literature; the
As far as we are aware, the only previously reported
gold complexes with (PPh2)2CdCH2 are [Au2Cl2{µ-
(PPh2)2CdCH2}] and [AuCl{µ-(PPh2)2CdCH2}]2; the
latter undergoes reversible addition of methanol.3,4
Here, we report a strong activation of the carbon-
carbon double bond of the diphosphine upon coordina-
tion to a gold(III) center; stable methanide complexes
are obtained after partial addition to the double bond.
Furthermore, the displacement of the ether ligands in
[Au(C6F5)2(OR2)2]ClO4 by the diphosphine (PPh2)2CdCH2
leads, surprisingly, to the complex [Au(C6F5)2{(PPh2)2-
CHCH2OR}]ClO4. This reaction represents an example
of an extremely facile O-C bond cleavage.
Resu lts a n d Discu ssion
† Universidad de la Rioja.
‡ Universidad de Zaragoza.
The reaction of (PPh2)2CdCH2 with [Au(µ-Cl)(C6F5)2]2
in a molar ratio of 2:1 leads to the complex [Au(C6F5)2-
Cl{PPh2C(dCH2)PPh2}] (1, Scheme 1). Complex 1 is a
yellow solid that is nonconducting in acetone (Table 1).
Its IR spectrum shows bands from the diphosphine at
1100 (s), 1060 (s), 1075 (s), 791 (m), and 485-624 (s)
cm-1, bands characteristic of cis-bis(pentafluorophenyl)
§ Institut fu¨r Anorganische und Analystische Chemie der Technis-
chen Universita¨t.
X Abstract published in Advance ACS Abstracts, February 15, 1997.
(1) Cooper, G. R.; McEwan, D. M.; Shaw, B. L. Inorg. Chim. Acta
1983, 76, L165.
(2) Cooper, G. R.; Hassan, F.; Shaw, B. L.; Thornton-Pett, M. J .
Chem. Soc., Chem. Commun. 1985, 614.
(3) Schmidbaur, H.; Herr, R.; Mu¨ller, G.; Riede, J . Organometallics
1985, 4, 1208.
(4) Schmidbaur, H.; Pollok, Th.; Herr, R.; Wagner, F. E.; Bau, R.;
Riede, J .; Mu¨ller, G. Organometallics 1986, 5, 566.
(5) Hassan, F. S. M.; Shaw, B. L.; Thornton-Pett, M. J . Chem. Soc.,
Dalton Trans. 1988, 89.
(6) Hassan, F. S. M.; Higgins, S. J .; J acobsen,G. B.; Shaw, B. L.;
Thornton-Pett, M. J . Chem. Soc., Dalton Trans. 1988, 3011.
(7) Higgins, S. J .; Shaw, B. L. J . Chem. Soc., Dalton Trans. 1989,
1527.
groups bonded to gold(III), and ν(Au-Cl) at 336 cm-1
.
The 31P{1H} NMR spectrum of 1 confirms the coor-
dination of the diphosphine ligand through one of the
phosphorus atoms (Table 2). The uncoordinated phos-
phorus appears as a doublet, close to the resonance of
(8) King, G.; Higgins, S. J .; Hopton, A. J . Chem. Soc., Dalton Trans.
1992, 3403.
(9) Higgins, S. J .; McCart, M. K.; McElhinney, M.; Nugent, D. C.;
Pounds, T. J . J . Chem. Soc., Chem. Commun. 1995, 2129.
(10) Schmidbaur, H.; Herr, R.; Riede, J . Angew. Chem., Int. Ed. Engl.
1984, 23, 247.
(11) Schmidbaur, H.; Herr, R.; Pollok, T.; Schier, A.; Mu¨ller, G.;
Riede, J . Chem. Ber. 1985, 118, 3105.
S0276-7333(96)00983-1 CCC: $14.00 © 1997 American Chemical Society

Synthesis of Gold(III) Methanide Complexes
Organometallics, Vol. 16, No. 6, 1997 1131
Sch em e 1a
a
R ) C6F5. Legend: (i) AgCCPh; (ii) TlCp; (iii) Tl(acac); (iv) H2O, O2; (v) HBF4; (vi) NaSPh; (vii) NaS2CNR′2; (viii) 1/2 Ag2O; (ix)
NaOEt; (x) HClO4; (xi) AgClO4, OR′2; (xii) [AuR2(OR′2)2]ClO4.
Ta ble 1. Yield , An a lytica l Da ta , Meltin g P oin t, a n d Con d u ctivity for th e Com p lexes 1-14, R ) C6F 5
analytical dataa
melting point (°C)b
Λm
c
complex
yield (%)
% C
% H
% N
% S
1, [AuR2Cl{PPh2C(dCH2)PPh2}]
2, [AuR2{(PPh2)2CCH2CtCPh}]
3, [AuR2{(PPh2)2CCH2(η1-C5H5)}]
4, [AuR2{(PPh2)2CCH2(acac)}]
5, [AuR{PPh2CH(PPh2O)CH2(acac)}]
6, [AuR2{(PPh2)2CHCH2(acac)}]BF4
7, [AuR2{(PPh2)2CCH2SPh}]
8, [AuR2{(PPh2)2CCH2S2CNMe2}]
9, [AuR2{(PPh2)2CCH2S2CNEt2}]
10, [AuR2{(PPh2)2CCH2S2CNBz2}]
11, [{AuR2{(PPh2)2CCH2}}2O]
12, [AuR2{(PPh2)2CCH2OEt}]
88
47
59
82
70
86
61
79
78
68
52
75
82
86
47.4 (47.9)
52.85 (53.7)
51.75 (52.05) 3.1 (2.75)
50.1 (50.3)
49.9 (50.75)
45.8 (46.35)
51.0 (51.0)
47.25 (47.0)
48.5 (48.0)
2.3 (2.3)
3.1 (2.65)
156 (dec)
110 (dec)
95
140 (dec)
155 (dec)
76
3
34
3
6
1
102
23
1
30
11
2.75 (2.85)
3.0 (3.35)
2.2 (2.7)
3.1 (2.85)
2.5 (2.7)
2.6 (3.0)
3.1 (3.1)
6.1 (6.1)
5.45 (5.95)
75
1.2 (1.35)
1.35 (1.3)
90 (dec)
105 (dec)
60
110
130
52.85 (53.05) 3.25 (3.0)
0.95 (1.15) 5.4 (5.35)
48.9 (48.8)
49.35 (49.4)
43.95 (44.8)
45.2 (45.25)
2.3 (2.35)
3.25 (2.8)
2.45 (2.55)
2.85 (2.75)
20
159
149
13, [AuR2{(PPh2)2CHCH2OEt}]ClO4
182 (dec)
190 (dec)
14, [AuR2{(PPh2)2CHCH2OiPr}]ClO4
a
b
Calculated values are given in parentheses. Or decomposition. c In acetone, Ω-1 cm2 mol-1
.
the free diphosphine, and the phosphorus bonded to
gold(III) appears as a multiplet because of the coupling
with the phosphorus and the fluorine nuclei. The 19F
NMR spectrum shows two different pentaflurophenyl
groups; two multiplets and a triplet appear for the
ortho-, meta-, and para-fluorine nuclei, respectively, of
each C6F5 group. In the 1H NMR spectrum, the two
vinylidene protons are inequivalent, each appearing as
a multiplet that sharpens only as far as two broad
doublets at -55 °C.
Complex 1 is a suitable starting material because it
can react with nucleophiles to give the methanide-type
species, as a result of the partial addition to the double
bond. First, we investigated reactions with several
carbon-based nucleophiles, such as AgCtCPh, TlCp,
and Tl(acac) (acac ) acetylacetonate); these react with
1, with precipitation of AgCl or TlCl and addition of the
nucleophile to the CH2 group, giving the methanide
derivatives [Au(C6F5)2{(PPh2)2CCH2Nu}] (Nu ) CtCPh
(2), Cp (3), acac (4)). Complexes 2-4 are yellow solids
that are stable to air and moisture. They are noncon-
ducting in acetone. Their 31P{1H} NMR spectra show
in all of the cases a multiplet, because of the coupling
of the equivalent phosphorus atoms with the fluorine
nuclei; the resonances appear at very high field, as we
have previously observed in this type of four-membered
ring system.12,13 The 19F NMR spectra of 2-4 now show
In the positive-ion fast atom bombardment mass
spectrum (FAB+) of 1, the molecular ion peak appears
at m/ z ) 959 (100). Other fragmentation peaks at m/ z
)
927 and 593 are assigned to [Au(C6F5)2-
{(PPh2)2CdCH2}]+ and [Au{(PPh2)2CdCH2}]+, respec-
tively, which will also be present in the subsequent
spectra of the complexes synthesized from 1.

1132 Organometallics, Vol. 16, No. 6, 1997
Ta ble 2. 1H a n d 31P {1H} NMR Da ta for th e Com p lexes 1-6, R ) C6F 5
Ferna´ndez et al.
a
1H NMR
P-CH-CH2
C-CH2-C
CH2-CH
C5H5
2CH3
31P NMR
1, [AuR2Cl{(PPh2)2CdCH2}]
2, [AuR2{(PPh2)2CCH2CtCPh}]
3, [AuR2{(PPh2)2CCH2(η1-C5H5)}]
4, [AuR2{(PPh2)2CCH2(acac)}]
6.26 (d), 6.08 (d)b
[J (H-P) ) 5.4 Hz]
3.42 (t)
[J (H-P) ) 25.7 Hz]
3.15 (t)
[J (H-P) ) 18.6 Hz]
2.55 (td)
[J (H-P) ) 20.7 Hz],
[J (H-H) ) 6.2 Hz]
2.35 (m)
34.6 (m), -8.4 (d)
[J (P-P) ) 50.4 Hz]
-32.2 (m)
6.15 (m), 5.85 (m),
5.79 (m), 1.99 (m)
-33.7 (m)
-32.8(m)
3.46 (t)
1.63 (s)
1.90 (s),
1.67 (s)
2.11 (s)
5, [AuR{PPh2CH(PPh2O)CH2(acac)}]
3.25 (m)
5.95 (m)
3.14 (m)
4.61 (m)
40.7 (m), 28.5 (d)
[J (P-P) ) 12.9 Hz]
-11.3 (m)
6, [AuR2{(PPh2)2CHCH2(acac)}]BF4
2.26 (m)
a
b
Recorded in CDCl3, values in ppm; s ) singlet, d ) doublet, t ) triplet, m ) multiplet. Registered at -50 °C.
only one type of pentafluorophenyl group. The 1H NMR
spectrum of 2 shows, apart from the resonances of the
phenyl protons, a multiplet for the methylene group.
The spectrum of complex 3 has five resonances, with a
relative intensity of 1:1:1:2:2, at 6.15 (m), 5.85 (m), 5.79
(m), 3.15 (t), and 1.99 (m); the triplet corresponds to the
methylene protons and the four remaining resonances
to the cyclopentadienyl protons. The high field peak is
assigned to the CH2 group and the low field ones to the
CH protons of the cyclopentadienyl ring (see Scheme
ation of the methanide carbon leads to a downfield
displacement for the resonance of the phosphorus atoms
(∆ ) 21.5 ppm). In the 1H NMR spectrum, four
resonances at 2.11 (s), 2.26 (m), 4.61 (m), and 5.95 (m)
appear; the first corresponds to the two methyl protons
of the acetylacetonate group, and the rest were assigned
from the 1H-1H (COSY) spectrum. The multiplet at
2.26 comes from the methylene protons, the multiplet
at 4.61 from the -CH- of the acac group, and, finally,
the multiplet at 5.95, with the relative intensity of 1:2:
3:4:3:2:1, corresponds to the methine proton coupled to
the phosphorus atoms and the protons of the methylene
1
1). The H-1H two-dimensional (COSY) spectrum for
3 agrees with this assignment. The spectrum of com-
plex 4 contains three resonances in a ratio of 6:2:1; the
first one is a singlet (2 Me), the second is a triplet of
doublets (CH2), because of the coupling of the methylene
protons with the equivalent phosphorus atoms and the
CH proton of the acetylacetonate, and the third one
appears as a triplet (CH).
3
group in such a manner that 2J (PH) is twice J (HH).
In the FAB+ spectrum, the molecular ion peak does
-
not appear, but the fragment due to the loss of the BF4
ion, [M - BF4]+, is present at m/ z ) 1027 (100) and
also the fragment [M - BF4 - acac]+ is present at m/ z
) 594 (25).
In the FAB+ mass spectra of complexes 2-4 the
molecular ion peaks appear at m/ z ) 1028 (2, 45), 992
(3, 100) and 1027 (4, 100).
We have also studied Michel-type addition reactions
with sulfur-based nucleophiles, such as thiolates and
dithiocarbamates. The treatment of 1 with NaSPh or
NaS2CNR2 in diethyl ether gives NaCl and the com-
plexes [Au(C6F5)2{(PPh2)2CCH2SPh}] (7) or [Au(C6F5)2-
{(PPh2)2CCH2S2CNR2}] (R ) Me (8), Et (9), Bz (10)).
The methanide complex 4 is not very stable in solution
and slowly changes from yellow to colorless. We have
previously observed that gold(III) methanide complexes
are unstable in solution because of their high reactivity
toward traces of water, protic solvents, etc. On leaving
a diethyl ether solution of 4 in air for 1 day, a white
solid is isolated and identified as [Au(C6F5){PPh2CH-
(PPh2O)CH2(acac)}] (5). A redox reaction has taken
place, and the gold(III) atom has been reduced to gold(I),
whereas one of the phosphorus atoms has been oxidized.
Phosphine oxidation at a gold(III) center has been
previously reported in other gold(III) derivatives.14 The
IR and the 19F NMR spectra of 5 agree with the presence
of a pentafluorophenyl group bound to gold(I); the
31P{1H} NMR spectrum of 5 shows two different phos-
phorus environments, both with a positive shift: one is
a multiplet, by coupling to the phosphorus and the
fluorine nuclei, and the other is a doublet. We have also
carried out the protonation reaction of 4 with a solution
of HBF4 in diethyl ether, leading to the complex
[Au(C6F5)2{(PPh2)2CHCH2(acac)}]BF4 (6), which has
also been isolated as a white solid. It behaves as a 1:1
electrolyte in acetone. The IR spectrum shows, as the
main difference from the starting material, a broad band
at 1100 cm-1 arising from the BF4- anion. The proton-
Complexes 7-10 are deep yellow solids that are
nonconducting in acetone. The 31P{1H} and 19F NMR
spectra are similar to those of the derivatives discussed
1
above. In the H NMR spectra, the methylene protons
appear as a triplet and in compounds 8-10 the reso-
nances of the inequivalent dithiocarbamate subtituents
are present (Table 3).
The positive-ion fast atom bombardment mass spectra
show the molecular ion peaks at m/ z ) 1037 (7, 22),
1046 (8, 100), 1076 (9, 100), and 1119 (10, 32).
The structures of complexes 7 and 9 have been
established by X-ray diffraction studies. The molecular
structure of 7 is shown in Figure 1, and selected bond
lengths and angles are given in Table 4. The gold(III)
center has a planar geometry, being bonded to the two
pentafluorophenyl groups and chelated by the diphos-
phine ligand; the ligand plane is coplanar with that of
the four-membered ring (mean deviation for six atoms
is 0.03 Å). The bite angle is very narrow, 69.87(9)°, and
is the main factor responsible for the deviation from
ideal (square planar) geometry.
The Au-C, 2.087(10) and 2.099(13) Å, and Au-P
distances, 2.322(3) and 2.355(2) Å, are similar to those
found in bis(pentafluorophenyl)diphosphine gold(III)
derivatives, such as [Au(C6F5)2{(PPh2)2CPPh2}]15 or
(12) Appleton, T. G.; Bennet, M. A.; Tomkins, I. B. J . Chem. Soc.,
Dalton Trans. 1981, 439.
(13) Garrou, P. G. Chem. Rev. 1981, 81, 229.
(14) Paul, M.; Schmidbaur, H. Chem. Ber. 1996, 129, 77.

Synthesis of Gold(III) Methanide Complexes
Organometallics, Vol. 16, No. 6, 1997 1133
a
Ta ble 3. 1H a n d 31P {1H} NMR Da ta for th e Com p lexes 7-14, R ) C6F 5
1H NMR
P-CH-CH2
C-CH2-O/S
3.59 (t)
[J (H-P) ) 20.7 Hz]
4.01 (t)
[J (H-P) ) 22.6 Hz]
4.00 (t)
[J (H-P) ) 23.0 Hz]
4.08 (t)
[J (H-P) ) 23.0 Hz]
3.43 (t)
[J (H-P) ) 25.7 Hz]
3.75 (t)
[J (H-P) ) 24.3 Hz]
3.97 (t)
[J (H-P) ) 23.1 Hz]
O/N-CH2-R
O/N-CH2-CH3 N-CH3 31P NMR
-31.5 (m)
7, [AuR2{(PPh2)2CCH2SPh}]
8, [AuR2{(PPh2)2CCH2S2CNMe2}]
9, [AuR2{(PPh2)2CCH2S2CNEt2}]
10, [AuR2{(PPh2)2CCH2S2CNBz2}]
11, [{AuR2{(PPh2)2CCH2}}2O]
12, [AuR2{(PPh2)2CCH2OEt}]
3.35 (s), -31.2 (m)
2.99 (s)
3.84 (m), 3.38 (m)
5.15 (s), 4.53 (s)
1.13 (m),
0.99 (m)
-31.0 (m)
-30.7 (m)
-32.2 (m)
-32.9 (m)
-21.8 (m)
3.06 (c)
[J (H-H) ) 6.2 Hz]
3.18 (q)
0.95 (t)
1.11 (t)
13, [AuR2{(PPh2)2CHCH2OEt}]ClO4 7.10 (t)
[J (H-P) ) 11.1 Hz],
[J (H-H) ) 2.0 Hz]
14, [AuR2{(PPh2)2CHCH2OiPr}]ClO4 7.12 (t)
[J (H-P) ) 11.1 Hz]
[J (H-H) ) 7.1 Hz]
3.99 (t)
[J (H-P) ) 23.1 Hz]
3.07 (sept)
[J (H-H) ) 6.1 Hz]
0.86 (d)
-23.9 (m)
a
Recorded in CDCl3, values in ppm; s ) singlet, d ) doublet, t ) triplet, q ) quartet, m ) multiplet, sept ) septet.
F igu r e 2. Molecular structure of complex 9 in the crystal
(50% ellipsoids), with the atom labeling scheme. H atoms
are omitted for clarity.
F igu r e 1. Molecular structure of complex 7 in the crystal
showing the atom numbering scheme. Displacement pa-
rameter ellipsoids represent 50% probability surfaces.
Carbon atoms are spheres of arbitrary radius. The H atoms
are omitted for clarity.
1.728(12) Å, shorter than those found in complexes with
the diphosphine, such as [AuCl{PPh2C(dCH2)PPh2}]2
(1.828(6) and 1.833(6) Å), or in other derivatives where
a Michael addition has taken place, such as [PdI2{(PPh2)2-
CHCH2OCH2CH2(3-SC4H3)}] (1.84(2) and 1.90(1) Å).
This indicates that the negative charge of the methanide
carbon is delocalized over the P-C bonds, conferring on
them a degree of multiple bonding. The C(1)-C(2) bond
distance, 1.52(2) Å, now corresponds to a single bond,
in contrast to that in the free phosphine (1.327(6) Å)17
or in [AuCl{PPh2C(dCH2)PPh2}]2 (1.326(9) Å).
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 7
Au-C(51)
Au-P(1)
2.087(10)
2.322(3)
1.716(11)
1.819(7)
1.819(7)
1.763(7)
1.52(2)
Au-C(61)
Au-P(2)
P(1)-C(11)
P(2)-C(1)
P(2)-C(41)
S-C(2)
2.099(13)
2.355(2)
1.801(7)
1.728(12)
1.830(7)
1.829(12)
P(1)-C(1)
P(1)-C(21)
P(2)-C(31)
S-C(71)
C(1)-C(2)
C(51)-Au-C(61)
C(61)-Au-P(1)
C(61)-Au-P(2)
C(1)-P(1)-C(11)
C(11)-P(1)-C(21)
C(11)-P(1)-Au
C(1)-P(2)-C(31)
C(31)-P(2)-C(41)
C(31)-P(2)-Au
C(71)-S-C(2)
90.7(4)
173.9(3)
104.3(3)
114.7(5)
104.8(4)
114.4(3)
115.2(5)
106.9(4)
114.0(3)
104.7(5)
131.0(9)
114.7(9)
121.5(8)
121.7(8)
C(51)-Au-P(1)
C(51)-Au-P(2)
P(1)-Au-P(2)
C(1)-P(1)-C(21)
C(1)-P(1)-Au
C(21)-P(1)-Au
C(1)-P(2)-C(41)
C(1)-P(2)-Au
C(41)-P(2)-Au
C(2)-C(1)-P(1)
P(1)-C(1)-P(2)
C(52)-C(51)-Au
C(62)-C(61)-Au
95.2(3)
164.8(3)
69.87(9)
114.2(5)
94.8(4)
114.2(3)
113.6(5)
93.3(4)
113.8(3)
126.9(9)
102.1(6)
120.6(8)
121.8(8)
The molecular structure of 9 is shown in Figure 2,
and selected bond lengths and angles are given in Table
5. Again, the gold(III) center has a square planar
geometry, distorted by the ligand bite angle, P-Au-P
) 69.97(6)°, and the ligand plane and four-membered
ring are coplanar (mean deviation of 0.04 Å). The bond
distances and angles around the methanide carbon C(1)
fit well to sp2 hybridization and are similar to those
discussed for complex 7. The C(2)-S(1) distance, 1.830(7)
Å, is of the same order as that in complex 7 (1.829(12)
C(2)-C(1)-P(2)
C(1)-C(2)-S
C(56)-C(51)-Au
C(66)-C(61)-Au
(15) Ferna´ndez, E. J .; Gimeno, M. C.; J ones, P. G.; Ahrens, B.;
Laguna, A.; Laguna, M.; Lo´pez de Luzuriaga, J . M. J . Chem. Soc.,
Dalton Trans. 1994, 3487.
(16) Uso´n, R.; Laguna, A.; Laguna, M.; Fernandez, E.; Villacampa,
M. D.; J ones, P. G.; Sheldrick, G. M. J . Chem. Soc., Dalton Trans. 1983,
1679.
[Au(C6F5)2{(PPh2)2CH2}]ClO4.16 The methanide carbon
atom displays a trigonal planar geometry with angles
of 131.0(9)°, 126.9(9)°, and 102.1(6)°; the smallest is the
P-C-P angle. The P-C distances are 1.716(11) and
(17) Schmidbaur, H.; Herr, R.; Riede, J . Chem. Ber. 1984, 117, 232.

1134 Organometallics, Vol. 16, No. 6, 1997
Ferna´ndez et al.
Ta ble 5. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 9
Au-C(11)
Au-P(2)
2.082(6)
2.335(2)
1.719(7)
1.826(7)
1.812(7)
1.771(8)
1.669(9)
1.471(12)
1.536(9)
Au-C(21)
Au-P(1)
2.086(7)
2.339(2)
1.825(8)
1.711(7)
1.817(8)
1.830(7)
1.329(9)
1.478(10)
P(1)-C(1)
P(1)-C(31)
P(2)-C(51)
S(1)-C(3)
S(2)-C(3)
N-C(6)
P(1)-C(41)
P(2)-C(1)
P(2)-C(61)
S(1)-C(2)
N-C(3)
N-C(4)
C(1)-C(2)
C(11)-Au-C(21)
C(21)-Au-P(2)
C(21)-Au-P(1)
C(1)-P(1)-C(41)
C(1)-P(1)-Au
C(31)-P(1)-Au
C(41)-P(1)-P(2)
Au-P(1)-P(2)
C(1)-P(2)-C(61)
C(51)-P(2)-Au
C(1)-P(2)-P(1)
C(61)-P(2)-P(1)
C(3)-S(1)-C(2)
C(3)-N-C(4)
88.2(3)
100.7(2)
169.7(2)
116.6(3)
93.4(2)
117.0(2)
128.9(2)
54.94(5)
112.8(3)
113.9(2)
38.7(2)
124.1(2)
103.7(3)
121.8(8)
127.2(6)
107.9(5)
113.8(6)
121.2(5)
120.7(6)
C(11)-Au-P(2)
C(11)-Au-P(1)
P(2)-Au-P(1)
C(1)-P(1)-C(31)
C(41)-P(1)-Au
C(1)-P(1)-P(2)
C(31)-P(1)-P(2)
C(1)-P(2)-C(51)
C(1)-P(2)-Au
C(61)-P(2)-Au
C(51)-P(2)-P(1)
Au-P(2)-P(1)
C(3)-N-C(6)
C(2)-C(1)-P(2)
P(2)-C(1)-P(1)
N-C(3)-S(2)
S(2)-C(3)-S(1)
C(16)-C(11)-Au
C(22)-C(21)-Au
170.9(2)
101.0(2)
69.97(6)
114.3(3)
112.2(2)
38.5(2)
126.5(2)
115.1(4)
93.7(2)
115.4(3)
128.9(3)
55.08(5)
123.7(7)
130.0(5)
102.8(4)
123.9(6)
122.2(4)
121.9(5)
123.6(6)
F igu r e 3. The structure of complex 11 in the crystal.
Displacement parameter ellipsoids represent 50% prob-
ability surfaces. C, F, and O atoms are spheres of arbitrary
radius. Hydrogen atoms are omitted for clarity.
Ta ble 6. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 11
Au-C(51)
Au-P(1)
P(1)-C(1)
P(1)-C(21)
P(2)-C(41)
C(1)-C(2)
2.03(3)
2.346(8)
1.79(4)
1.80(2)
1.77(2)
1.42(4)
Au-C(61)
Au-P(2)
P(1)-C(11)
P(2)-C(31)
P(2)-C(1)
C(2)-O
2.08(3)
2.363(8)
1.797(14)
1.76(2)
1.78(3)
1.49(3)
C(2)-C(1)-P(1)
C(1)-C(2)-S(1)
N-C(3)-S(1)
C(12)-C(11)-Au
C(26)-C(21)-Au
C(51)-Au-C(61)
C(61)-Au-P(1)
C(61)-Au-P(2)
C(1)-P(1)-C(11)
89.9(8)
101.2(6)
170.5(6)
C(51)-Au-P(1)
C(51)-Au-P(2)
P(1)-Au-P(2)
168.9(6)
99.0(6)
69.9(3)
115.6(13) C(1)-P(1)-C(21) 109.1(13)
Å). The C(3)-S(1) and C(3)-S(2) bond lengths are
1.771(8) and 1.669(9) Å, respectively, which indicates
the presence of double bond character for S(2)-C(3).
Finally, we have carried out addition reactions of 1
with oxygen-based nucleophiles, such as Ag2O (molar
ratio of 2:1) or NaOEt, affording the complexes
[{Au(C6F5)2{(PPh2)2CCH2}}2O] (11) or [Au(C6F5)2{(PPh2)2-
CCH2OEt}] (12). Both are deep yellow solids that are
nonconducting in acetone. Their 31P{1H} NMR spectra
show one multiplet arising from the coupling of the
equivalent phosphorus atoms with the fluorine nuclei.
In the 19F NMR spectra, both pentafluorophenyl groups
are equivalent. In the 1H NMR spectrum of 11, the
methylene protons are coupled to both phosphorus
atoms and appear as a triplet; the spectrum of 12 shows,
besides the triplet for the methylene group, the reso-
nances of the CH3-CH2- protons that appear as a
triplet and a quartet, respectively.
C(11)-P(1)-C(21) 103.9(9)
C(11)-P(1)-Au 115.5(7)
C(1)-P(1)-Au
C(21)-P(1)-Au
95.6(12)
117.4(7)
C(31)-P(2)-C(41) 107.0(10) C(31)-P(2)-C(1) 110(2)
C(41)-P(2)-C(1)
C(41)-P(2)-Au
C(2)-C(1)-P(2)
P(2)-C(1)-P(1)
C(2*)-O-C(2)a
116.9(13) C(31)-P(2)-Au
111.4(7)
95.4(12)
130(3)
115.5(8)
132(3)
98(2)
C(1)-P(2)-Au
C(2)-C(1)-P(1)
C(1)-C(2)-O
109(2)
106(3)
a
Symmetry transformations used to generate equivalent atoms
(designated by *): -x + 1, -y + 1, z.
C(1)-C(2) of 1.42(4) Å, although imprecise, is not
inconsistent with a carbon-carbon single bond. The
P-C distances are 1.78(3) and 1.79(4) Å, shorter than
those in [PdI2{(PPh2)2CHCH2OCH2CH2C4H5S-3}] (1.84(2)
and 1.85(2) Å) where the carbon was protonated.
When complex 12 is treated with a solution of HClO4,
the color changes inmediately from yellow to colorless
with the formation of the protonated species [Au-
(C6F5)2{(PPh2)2CHCH2OEt]ClO4 (13). In order to carry
out further addition reactions, we have tried to prepare
the derivative [Au(C6F5)2{(PPh2)2C(dCH2)}]+, which
could be used to add several nucleophiles. The treat-
ment of 1 with AgClO4 in diethyl ether led surprisingly
to complex 13, and furthermore, the reaction of [Au-
(C6F5)2(OR2)2]ClO4 with (PPh2)2CdCH2 gave the same
derivatives, [Au(C6F5)2{(PPh2)2CHCH2OR}]ClO4 (R )
In the positive-ion fast atom bombardment mass
spectra, the molecular ion peak is present for complex
12 at m/ z ) 973 (100) and for 11 the fragment [M -
C6F5]+ appears at m/ z ) 1703 (15).
The structure of complex 11 has been established by
X-ray diffraction studies and is shown in Figure 3, and
selected bond lengths and angles are given in Table 6.
The molecule has crystallographic 2-fold symmetry. The
precision was limited by the weak diffraction and the
noncentrosymmetry. The one independent gold atom
again shows a distorted square planar geometry (mean
deviation of five atoms is 0.03 Å), with a diphosphine
bite angle of 69.9(3)°. In contrast to 7 and 9, the four-
membered ring is slightly folded (by 9°) about the P‚‚‚P
axis. The distances Au-C and Au-P are of the same
order as those found in other methanide complexes,15,18
and the methanide carbon is trigonal, with angles of
132(3)°, 130(3)°, and (P-C-P) 98(2)°. The distance
i
Et (13), Pr (14)).
We believe that in this reaction the first step could
be the formation of the expected complex [Au(C6F5)2-
{(PPh2)2CdCH2}]ClO4; this should be very reactive
toward Michael addition reactions and react even with
a weak nucleophile, such as an ether, giving the
complexes [Au(C6F5)2{(PPh2)2CCH2OR2}]ClO4 (Scheme
2). The following step could be the nucleophilic attack
of H2O, affording complexes 13 and 14 and one molecule
of alcohol. We have detected ethanol or 2-propanol in
1
the H NMR spectra; furthermore, we have carried out
(18) Ferna´ndez, E. J .; Gimeno, M. C.; J ones, P. G.; Laguna, A.;
Laguna, M.; Lo´pez de Luzuriaga, J . M. J . Chem. Soc., Dalton Trans.
1992, 3365.
the same reaction of [Au(C6F5)2(OEt2)2]ClO4 with
(PPh2)2CdCH2 under a nitrogen atmosphere and with

Synthesis of Gold(III) Methanide Complexes
Organometallics, Vol. 16, No. 6, 1997 1135
Sch em e 2a
p-F, J (FF) ) 19.9 Hz), -161.9 (m, m-F); 4 -121.5 (m, o-F),
-158.1 (t, p-F, J (FF) ) 20.0 Hz), -162.0 (m, m-F).
Syn t h esis of [Au (C6F 5){P P h 2CH (P P h 2O)CH2(a ca c)}]
(5). A solution of complex 4 (0.206 g, 0.2 mmol) in diethyl
ether (20 mL) was stirred at room temperature for 1 day. The
solution turned colorless, and a white precipitate was formed.
Concentration of the solvent in vacuo (10 mL) and addition of
hexane completed the precipitation of the white solid of
complex 5. 19F NMR, δ: -116.4 (m, o-F), -158.4 (t, p-F, J (FF)
) 20.0 Hz), -162.5 (m, m-F).
Syn th esis of [Au (C6F 5)2{(P P h 2)2CHCH2(a ca c)}]BF 4 (6).
To a solution of complex 4 (0.206 g, 0.2 mmol) in 20 mL of
diethyl ether was added HBF4 (0.2 mmol, 54% in diethyl
ether). The solution turned colorless, and a white precipitate
was formed. After 15 min of stirring, the solid was filtered
off to yield complex 6. 19F NMR, δ: -121.3 (m, o-F), -153.7
(t, p-F, J (FF) ) 19.9 Hz), -159.0 (m, m-F).
a
R ) C6F5. Legend: (i) AgClO4, -AgCl; (ii) R′2O; (iii) H2O,
-R′OH.
Syn th esis of [Au (C6F 5)2{(P P h 2)2CCH2Nu }] (Nu ) SP h
(7), S2CNMe2 (8), S2CNEt2 (9), S2CNBz2 (10)). To a solution
of 1 (0.193 g, 0.2 mmol) in diethyl ether (20 mL) was added
NaSPh (0.027 g, 0.2 mmol), NaS2CNMe2‚2H2O (0.036 g, 0.2
mmol), NaS2CNEt2‚3H2O (0.045 g, 0.2 mmol), or NaS2CNBz2
(0.059 g, 0.2 mmol), and the suspension was stirred for 1 h.
The solid NaCl was filtered off, and the yellow solution was
evaporated to 5 mL. Addition of hexane (10 mL) gave
complexes 7-10 as yellow solids. 19F NMR δ: 7 -121.2 (m,
o-F), -157.6 (t, p-F, J (FF) ) 19.9 Hz), -161.7 (m, m-F); 8
-121.2 (m, o-F), -157.6 (t, p-F, J (FF) ) 19.9 Hz), -161.7 (m,
m-F); 9 -121.2 (m, o-F), -157.6 (t, p-F, J (FF) ) 19.8 Hz),
-161.7 (m, m-F); 10 -121.2 (m, o-F), -157.6 (t, p-F, J (FF) )
19.8 Hz), -161.6 (m, m-F).
Syn th esis of [{Au (C6F 5)2{(P P h 2)2CCH2}}2O] (11). To a
tetrahydrofuran solution (20 mL) of complex 1 (0.193 g, 0.2
mmol) was added Ag2O (0.023 g, 0.12 mmol). The mixture was
stirred for 6 h, the white precipitate of AgCl was filtered off,
and the yellow solution was concentrated to 5 mL; addi-
tion of hexane gave complex 11 as a yellow solid. 19F NMR,
δ: -120.9 (m, o-F), -157.5 (t, p-F, J (FF) ) 19.9 Hz), -161.6
(m, m-F).
dry ether, leading to a new, unstable complex whose
spectroscopic data correspond to the intermediate
[Au(C6F5)2{(PPh2)2CCH2OEt2}]ClO4. Thus, it seems
clear that traces of water are necessary to give the
alcohol.
Exp er im en ta l Section
In str u m en ta tion a n d Ma ter ia ls. IR spectra were re-
corded on a Perkin-Elmer 883 spectrophotometer, over the
range 2000-200 cm-1, using Nujol mulls between polyethylene
sheets. 1H, 19F, and 31P NMR spectra were recorded on a
Varian UNITY 300 and Bruker ARX 300 spectrometers in
CDCl3 solutions; chemical shifts are quoted relative to SiMe4
(1H, external), CFCl3 (19F, external), and H3PO4 (31P, external).
C, H, N, and S analyses were performed with a Perkin-Elmer
2400 microanalyzer. Conductivities were measured in ca. 5
× 10-4 mol dm-3 acetone solutions with a J enway 4010
conductimeter, and ΛM is given in Ω-1 cm2 mol-1
. Mass
spectra were recorded on a VG Autospec using FAB techniques
and nitrobenzyl alcohol as the matrix. The starting materials
Syn th esis of [Au (C6F 5)2{(P P h 2)2CCH2OEt}] (12). To a
solution of complex 1 (0.193 g, 0.2 mmol) in diethyl ether (20
mL) was added an ethanol solution of NaOEt (2.06 mL, 0.097
M, 0.2 mmol). The mixture was stirred for 30 min and then
filtered to remove NaCl. Concentration to ca. 2 mL and
addition of hexane (15 mL) afforded complex 12 as a yellow
solid.
19
20
(PPh2)2CdCH2 and [Au(µ-Cl)(C6F5)2]2 were prepared as
described earlier; [Au(C6F5)2(OR2)2]ClO4 was prepared from
trans-[Au(C6F5)2Cl2] and 2 equiv of AgClO4 in ether. The
syntheses of the methanide complexes were carried out under
a nitrogen atmosphere and with freshly distilled solvents.
Sa fety Note! Perchlorate salts of metal complexes with
organic ligands are potentially explosive. Only small amounts
of the material should be prepared, and these should handled
with great caution.
Syn th esis of [Au (C6F 5)2Cl{P P h 2C(dCH2)P P h 2}] (1). To
a solution of (Ph2P)2CdCH2 (0.079 g, 0.2 mmol) in dichloro-
methane (20 mL) was added [Au(µ-Cl)(C6F5)2]2 (0.113 g, 0.1
mmol); the solution turned yellow. After the solution was
stirred for 1 h, the solvent was concentrated to 5 mL and
addition of hexane gave complex 1 as a yellow solid. 19F NMR,
δ: -122.1 (m, o-F), -123.2 (m, o-F), -156.7 (t, p-F, J (FF) )
19.3 Hz), -160.0 (m, m-F), -160.1 (m, m-F).
Syn th esis of [Au (C6F5)2{(P P h 2)2CCH2Nu }] (Nu ) CtCP h
(2), Cp (3), a ca c (4)). To a solution of 1 (0.193 g, 0.2 mmol)
in diethyl ether (20 mL) was added AgCtCPh (0.050 g, 0.24
mmol), TlCp (0.065 g, 0.24 mmol), or Tl(acac) (0.073 g, 0.24
mmol); the suspension was stirred for 1 h. The AgCl or TlCl
was filtered off, and the yellow solution was evaporated to 5
mL. Addition of hexane (10 mL) gave complexes 2-4 as yellow
solids. 19F NMR, δ: 2 -121.0 (m, o-F), -157.5 (t, p-F, J (FF)
) 19.9 Hz), -161.6 (m, m-F); 3 -121.1 (m, o-F), -158.1 (t,
19F NMR, δ: -120.9 (m, o-F), -157.8 (t, p-F, J (FF) )
19.8 Hz), -161.7 (m, m-F).
Syn th esis of [Au (C6F 5)2{(P P h 2)2CHCH2OR}]ClO4 (R )
Et (13), iP r (14)). To a freshly prepared solution of [Au(C6F5)2-
(OR2)2]ClO4 (0.2 mmol) in OR2 (20 mL) was added
(PPh2)2CdCH2 (0.079 g, 0.2 mmol), and the mixture was
stirred for 4 h. Complexes 13 (62%) and 14 (70%) precipitated
and were filtered off. 19F NMR, δ: 13 -119.7 (m, o-F), -153.7
(t, p-F, J (FF) ) 19.8 Hz), -158.8 (m, m-F); 14 -119.3 (m, o-F),
-153.4 (t, p-F, J (FF) ) 20.0 Hz), -158.7 (m, m-F).
X-r ay Str u ctu r e Deter m in ation s. Crystals were mounted
in inert oil on glass fibers. Data were collected using mono-
chromated Mo KR radiation (λ ) 0.710 73). Diffractometer
type: Siemens P4 equipped with a Siemens or Oxford low-
temperature attachment. Scan type: ω (7, 11) or ω/θ (9). Cell
constants were refined from setting angles of ca. 50 reflections
in the range 2θ ) 10-25°. Absorption corrections were applied
on the basis of Ψ-scans. Structures were solved by the heavy-
atom method and refined on F2 (program SHELXL-93).21
Special refinement details: The structure of complex 7 has a
marked pseudosymmetry; the gold atom lies on a pseudo-
special position (z ) 0.5), and this results in weak reflections
with l odd. The structure was extended slowly by successive
(19) Colquhoun, I. J .; McFarlane, W. J . Chem. Soc., Dalton Trans.
1982, 1915.
(20) Uso´n, R.; Laguna, A.; Laguna, M.; Abad, A. J . Organomet.
Chem. 1983, 249, 437.
(21) Sheldrick, G. M. SHELXL-93,
Structure Refinement; University of Go¨ttingen: Go¨ttingen, Germany,
1993.
A Program For Crystal

1136 Organometallics, Vol. 16, No. 6, 1997
Ferna´ndez et al.
Ta ble 7. Deta ils of Da ta Collection a n d Str u ctu r e Refin em en t for th e Com p lexes 7, 9, a n d 11
7
9‚1.5C2H4Cl2
11‚4C2H4Cl2
chem form
cryst habit
cryst size/mm
cryst syst
space group
a/Å
C44H27AuF10P2S
yellow prism
0.40 × 0.30 × 0.30
monoclinic
P21/c
10.208(2)
18.298(2)
21.198(3)
102.582(12)
3864.4(10)
4
1.782
1036.62
2024
-100
50
4.025
0.589-0.732
7101
6711
0.074
0.054
0.157
C46H38AuCl3F10NP2S2
yellow tablet
0.70 × 0.40 × 0.10
monoclinic
P21/c
14.9010(10)
13.7600(10)
23.985(2)
92.966(7)
4911.2(6)
4
1.656
1224.15
2412
-100
50
3.380
0.549-1.0
11920
8570
0.043
0.044
0.132
C84H60Au2Cl8F20OP4
yellow plate
0.20 × 0.20 × 0.10
tetragonal
P4h21c
19.574(3)
b/Å
c/Å
19.574(3)
22.569(6)
â/deg
U/Å3
8647(3)
4
Z
Dc/Mg m-3
M
1.741
2266.73
4424
-100
45
3.799
0.45-0.48
3310
3237
0.31
0.071
0.107
226
99
0.84
F(000)
T/°C
2θmax/deg
µ(Mo KR)/mm-1
transmission
no. of reflns measd
no. of unique reflns
Rint
Ra(F, F>4σ(F))
wR(F2, all reflns)b
no. of params
no. of restraints
Sc
243
143
0.98
1.28
588
0
0.91
1.40
max ∆F/eÅ-3
0.90
a
b
2
2
R(F) ) ∑||Fo| - |Fc||/∑|Fo|. wR (F2) ) [∑{w(Fo - Fc2)2}/∑{w(Fo2)2}]0.5; w-1 ) σ2(Fo2) + (aP)2 + bP, where P ) [Fo + 2Fc2]/3 and a
and b are constants adjusted by the program. c S ) [∑{w(Fo - Fc2)2}/(n - p)]0.5, where n is the number of data and p the number of
parameters.
2
difference maps, the double images being gradually resolved.
An anisotropic refinement of the light atoms was not consid-
ered suitable. The crystals of complex 11 were small and
diffracted weakly (the complex crystallizes with two molecules
of 1,2-dichloroethane in the asymmetric unit, one of which is
badly resolved). Heavy atoms (Au, P, Cl) were refined aniso-
tropically, others isotropically. Pentafluorophenyl rings were
restrained to a local 2-fold symmetry. Phenyl rings were
idealized. Other H atoms were included using a riding model.
The absolute structure was determined by an x refinement;22
x ) -0.02(2). Further details are given in Table 7.
Ack n ow led gm en t. We thank the Direccio´n General
de Investigacio´n Cient´ıfica y Te´cnica (No. PB94-0079),
the Fonds der Chemischen Industrie for financial sup-
port, and the Instituto de Estudios Riojanos for a grant
to E.O.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data, data collection, and solution and refinement parameters,
bond distances and angles, and anisotropic thermal param-
eters (22 pages). Ordering information is given on any current
masthead page.
(22) Flack, H. D. Acta Crystallogr. 1983, A39, 876.
OM9609832