Perhalophenyl(tetrahydrothiophene)gold(I) complexes as lewis bases in acid-base reactions with silver trifluoroacetate

Article abstract of DOI:10.1021/om700701m

Reaction of [Ag(CF₃CO₂)] with [Au(C₆X ₅)(tht)] (X = halogen, tht = tetrahydrothiophene) leads to the synthesis of complexes [AgAu(C₆F₅)(CF₃CO ₂)(tht)]_n (1), [Ag₂Au(C₆Cl ₂F₃)(CF₃CO₂)₂(tht)] _n (2), or [AgAu(C₆Cl₅)(CF₃CO ₂)(tht)]_n (3), confirming the capability of a neutral complex, such as a perhalophenyl-(tetrahydrothiophene)gold(I), to act as electron density donor when treated with a Lewis acid substrate. All three crystal structures have been established by X-ray diffraction; all display Au...Ag and Ag...Ag interactions and polymeric 1D (2, 3) or 2D (1) networks built by means of additional Au...Au, Ag-O...Ag, or Au-S...Ag interactions. Complexes 1-3 are luminescent in the solid state at room temperature, and at 77 K or in frozen solutions they show a different luminescence in the solid state, which seems to be related to the different number and types of metal-metal interactions present in each case. DFT and TDDFT calculations on simplified model systems of 1-3 have also been carried out.

Full text of DOI:10.1021/om700701m

Organometallics 2007, 26, 5931-5939
5931
Perhalophenyl(tetrahydrothiophene)gold(I) Complexes as Lewis
Bases in Acid-Base Reactions with Silver Trifluoroacetate†
Eduardo J. Ferna´ndez,*,§ Peter G. Jones,# Antonio Laguna,*,‡ Jose´ M. Lo´pez-de-Luzuriaga,§
Miguel Monge,§ M. Elena Olmos,§ and Raquel C. Puelles§
Departamento de Qu´ımica, UniVersidad de la Rioja, Grupo de S´ıntesis Qu´ımica de La Rioja, UA-CSIC,
Complejo Cient´ıfico Tecnolo´gico, 26006 Logron˜o, Spain, Departamento de Qu´ımica Inorga´nica, Instituto
de Ciencia de Materiales de Arago´n, UniVersidad de Zaragoza-CSIC, 50009 Zaragoza, Spain, and
Institut fu¨r Anorganische und Analytische Chemie der Technischen UniVersita¨t,
Postfach 3329, D-38023 Braunschweig, Germany
ReceiVed July 13, 2007
Reaction of [Ag(CF3CO2)] with [Au(C6X5)(tht)] (X ) halogen, tht ) tetrahydrothiophene) leads to
the synthesis of complexes [AgAu(C6F5)(CF3CO2)(tht)]n (1), [Ag2Au(C6Cl2F3)(CF3CO2)2(tht)]n (2), or
[AgAu(C6Cl5)(CF3CO2)(tht)]n (3), confirming the capability of a neutral complex, such as a perhalophenyl-
(tetrahydrothiophene)gold(I), to act as electron density donor when treated with a Lewis acid substrate.
All three crystal structures have been established by X-ray diffraction; all display Au‚‚‚Ag and Ag‚‚‚Ag
interactions and polymeric 1D (2, 3) or 2D (1) networks built by means of additional Au‚‚‚Au, Ag-
O‚‚‚Ag, or Au-S‚‚‚Ag interactions. Complexes 1-3 are luminescent in the solid state at room temperature,
and at 77 K or in frozen solutions they show a different luminescence in the solid state, which seems to
be related to the different number and types of metal-metal interactions present in each case. DFT and
TDDFT calculations on simplified model systems of 1-3 have also been carried out.
(I)7e,f salts in the presence or absence of ancillary ligands, which
demonstrates the capability of bis(perhalophenyl)aurate(I) anions
to act as Lewis bases.
Introduction
Aurophilic Au(I)‚‚‚Au(I) interactions have traditionally been
the most studied nonbonding contacts between closed-shell
metals,1 but complexes with metallophilic interactions between
gold(I) and other closed-shell metal atoms (Au‚‚‚M) have
attracted great interest over the past years because of their
theoretical interest,2 the photophysical properties of the com-
plexes,3 or their potential applications.4 A number of species
displaying Au(I)‚‚‚Ag(I) interactions have been described to
date, most of them containing bidentate ligands between AuI
and AgI,5 although there are also compounds in which such
interactions are supported only by an ylide,5j,k a phenylacetylide,6
or an aryl bridging ligand7 or even a number of examples that
display unsupported Au‚‚‚Ag interactions.8 In the last few years
the acid-base strategy has been shown to be an effective method
for the synthesis of heteropolynuclear compounds with unsup-
ported Au‚‚‚M contacts; a number of AuI/TlI or AuI/AgI species
displaying such interactions have been prepared by reaction of
NBu4[Au(C6X5)2] (X ) halogen) with thallium(I)4b,9 or silver-
The neutral derivatives [Au(C6X5)(tht)] (X ) halogen, tht )
tetrahydrothiophene) are well-known starting materials for the
synthesis of gold(I) complexes through displacement reactions
of the weakly coordinated ligand tht by other neutral or anionic
ligands, resulting in the formation of mononuclear [Au(C6X5)L]
or [Au(C6X5)X′]- (L, X′ ) monodentate ligands) or polynuclear
[{Au(C6X5)}nL] or [{Au(C6X5)}nX′]n- (L, X′ ) polydentate
ligands) compounds that often display aurophilic interactions.10
Moreover, the pentafluorophenyl derivative [Au(C6F5)(tht)] can
also act as a deprotonating agent when it is treated with Ph2P-
(O)H, affording the synthesis of [H(Ph2PO)2Au]2 with displace-
ment of tht and formation of C6F5H.11 Another perhalophenyl
gold(I) complex, [Au(3,5-C6Cl2F3)(tht)], has been found to be
a very efficient catalyst for the isomerization of trans-[Pd(3,5-
C6Cl2F3)2(tht)2] to cis-[Pd(3,5-C6Cl2F3)2(tht)2], in a reaction that
(5) (a) Ro¨mbke, P.; Schier, A.; Schmidbaur, H.; Cronje, S.; Raubenhe-
imer, H. Inorg. Chim. Acta 2004, 357, 235. (b) Ferna´ndez, E. J.; Lo´pez-
de-Luzuriaga, J. M.; Monge, M.; Rodr´ıguez, M. A.; Crespo, O.; Gimeno,
M. C.; Laguna, A.; Jones, P. G. Chem. Eur. J. 2000, 6, 636. (c) Wang,
Q.-M.; Lee, Y.-A.; Crespo, O.; Deaton, J.; Tang, C.; Gysling, H. J.; Gimeno,
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Chem. Soc. 2004, 126, 9488. (d) Olmos, M. E.; Schier, A.; Schmidbaur, H.
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Gimeno, M. C.; Jones, P. G.; Laguna, A.; Lo´pez-de-Luzuriaga, J. M.; Olmos,
M. E. J. Chem. Soc., Dalton Trans. 2002, 1319. (f) Catalano, V. J.; Horner,
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Vicente, J.; Chicote, M. T.; Lagunas, M. C.; Jones, P. G. J. Chem. Soc.,
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† Dedicated to Prof. Maria Pilar Garcia on the occasion of her 60th
birthday.
* Authors to whom correspondence should be addressed. E-mail:
alaguna@unizar.es; eduardo.fernandez@unirioja.es.
§ Universidad de la Rioja.
‡ Universidad de Zaragoza-CSIC.
# Technische Universita¨t Braunschweig.
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10.1021/om700701m CCC: $37.00 © 2007 American Chemical Society
Publication on Web 10/24/2007

5932 Organometallics, Vol. 26, No. 24, 2007
Ferna´ndez et al.
Scheme 1. Synthesis of Complexes 1-3
takes place through a novel reversible aryl exchange between
Pd(II) and Au(I).12 Thus, [Au(C6X5)(tht)] have been mainly
employed in displacement reactions, but their behavior as Lewis
bases, similarly to [Au(C6X5)2]- anions, has not been reported
to date.
Considering all these precedents, we wondered if the neutral
derivatives [Au(C6X5)(tht)] could act as electron density donors
when treated with a Lewis acid, such as a silver(I) salt. We
therefore treated various [Au(C6X5)(tht)] complexes with silver
trifluoroacetate, which has been previously employed in acid-
base reactions with the neutral complex mesitylgold(I),7e in order
to obtain heterometallic AuI/AgI systems with Au‚‚‚Ag interac-
tions. In principle, the products could display a different Au/
Ag ratio depending on the halogen atoms present in the gold
precursor. The crystal structures of the resulting complexes have
been determined by X-ray diffraction methods, and their optical
properties have been experimentally and theoretically studied
in order to rationalize the results.
neutral arylgold(I) derivative is also able to act as electron
density donor toward the acid silver(I) salt. The same product
is also obtained when the reaction is carried out in different
molar ratios, such as 1:2 or 1:4, which indicates that the Au/
Ag ratio depends on the perhalophenyl group and not on the
molar ratio employed in the reaction. It is isolated as an air-
stable white solid, whose analytical and spectroscopic data agree
with the proposed formulation and that is nonconducting in
acetone solution. Its IR spectrum shows, among others, absorp-
tions at 1504 (vs), 981 (vs), and 796 (vs) cm-1 arising from the
presence of a pentafluorophenyl group bonded to gold(I), at 1627
(vs, br) and 1192 (vs, br) cm-1 from trifluoroacetate, and at
1264 (s) characteristic of the tht molecule. The presence of tht
is also confirmed in its 1H NMR spectrum, which displays two
multiplets at 2.21 and 3.44 ppm, and its 19F NMR spectrum
shows the typical pattern of a pentafluorophenyl group bonded
to gold(I) and a singlet at -73.1 ppm due to trifluoroacetate.
The mass spectrum of 1 using MALDI-TOF (matrix-assisted
laser desorption/ionization-time of flight) technique displays
peaks at m/z ) 865 (100%, [Ag3(CF3CO2)4(tht)]-) and 531
(65%, [Au(C6F5)2]-), which suggests a certain degree of
association.
Results and Discussion
Synthesis and Characterization. As mentioned in the
Introduction, we tried to study the influence of the perhalophenyl
groups in the resulting Au/Ag complexes in order to rationalize
their basic character. As expected, the gold(I) derivatives [Au-
(C6X5)(tht)] (C6X5 ) C6F5, 3,5-C6Cl2F3, C6Cl5) react with
[Ag(CF3CO2)] in a dissimilar manner, leading to products with
different stoichiometry depending on the aryl group present in
the starting material (see Scheme 1).
Treatment of [Au(C6F5)(tht)] with equimolecular amounts of
[Ag(CF3CO2)] in diethyl ether leads to the synthesis of a
complex of stoichiometry [AgAu(C6F5)(CF3CO2)(tht)]n (1),
according to the molar ratio employed, confirming that the
When the aryl group present in the starting complex is 3,5-
C6Cl2F3, treatment of [Au(3,5-C6Cl2F3)(tht)] with [Ag(CF3CO2)]
in dichloromethane leads to the synthesis of a complex with a
lower Au/Ag ratio: [Ag2Au(C6Cl2F3)(CF3CO2)2(tht)]n (2). When
the reaction is carried out in diethyl ether, the same complex is
obtained, but in lower yield. Complex 2 is the product of the
reaction independent of the molar ratio of the starting materials,
which suggests that the substitution of two fluorine atoms by
the less electronegative halogen chlorine leads to a more basic
gold(I) reagent that binds two silver centers per gold atom.
Complex 2 is isolated as a pale yellow solid stable to air and
moisture and is nonconducting in acetone solutions. The
analytical and spectroscopic data agree with the proposed
formulation, and thus its FT-IR spectrum in Nujol mulls shows,
besides the bands arising from tht and trifluoroacetate, absorp-
tions at 1586 (s), 1556 (m), 1061 (vs), and 771 (vs) cm-1 due
to the aryl group bonded to gold(I). Its 1H NMR spectrum shows
two multiplets at 2.21 and 3.43 ppm, corresponding to tht, and
the resonances of the fluorine atoms of the trifluoroacetate and
3,5-dichlorotrifluorophenyl groups are observed in its 19F NMR
spectrum at -73.1 ppm, and at -89.8 and -115.9 ppm,
respectively. Again, a certain degree of association in solution
is suggested by the mass spectrum of 2 (MALDI-TOF),
which shows peaks at m/z ) 997 (27%), 865 (13%), and 597
(100%), corresponding to the fragments [Au2(3,5-C6Cl2F3)3]-,
[Ag3(CF3CO2)4(tht)]-, and [Au(C6Cl2F3)2]-, respectively.
Finally, when all the fluorine atoms of the gold(I) starting
complex are substituted by chlorine, an even lower Au/Ag would
be expected in the resulting product in accordance with a more
basic character of the substrate. Notwithstanding, the reaction
of [Au(C6Cl5)(tht)] with [Ag(CF3CO2)] in diethyl ether leads
to a new complex of stoichiometry [AgAu(C6Cl5)(CF3CO2)-
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M.; Montiel, M.; Olmos, M. E. Inorg. Chem. 2007, 46, 2953. (b) Ferna´ndez,
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Perhalophenyl(tetrahydrothiophene)gold(I) Complexes
Organometallics, Vol. 26, No. 24, 2007 5933
Figure 1. Asymmetric unit of the crystal structure of complex 1
(30% probability level) with the labeling scheme of the atom
positions. Hydrogen atoms have been omitted for clarity.
(tht)]n (3), even when it is not carried out with equimolecular
amounts of the reagents. Compound 3 is isolated as a white
air-stable powder, and it behaves as a nonconductor in acetone
solution. Its IR spectrum shows bands from the aryl group
bonded to gold(I) at 843 (vs) and 628 (s) cm-1, from the tht
ligand at 1259 (s) cm-1, and from the trifluoroacetate anion at
1643 (vs, br) and 1202 (vs, br) cm-1. Its 1H NMR spectrum is
very similar to those of 1 and 2 and confirms the presence of
tht with two multiplets at 2.20 and 3.40 ppm. The 19F NMR of
3, which shows a singlet at -73.1 ppm, indicates a similar
behavior of the trifluoroacetate anion in the three complexes.
Finally, its mass spectrum (MALDI-TOF) displays peaks at m/z
) 1140 (10%) and 694 (100%), which correspond to the
fragments [Au2(C6Cl5)3]- and [Au(C6Cl5)2]-, respectively.
Crystal Structures. The crystal structures of complexes 1-3
were determined by X-ray diffraction methods from single
crystals obtained by slow diffusion of n-hexane into a solution
of the complex in dichloromethane. They are shown in Figures
1-6; Table 1 contains details of the data collection and
refinement methods, and selected bond lengths and angles are
shown in Tables 2-4. Although the three crystal structures are
different, they display some common features: all of them are
polymers formed by the association of linear [Au(C6X5)(tht)]
units and eight-membered [Ag2(CF3CO2)2] rings, assembled
through Au‚‚‚Ag contacts and various other interactions that
depend on the aryl group.
Figure 2. (a) Two-dimensional structure of complex 1. Hydrogen,
fluorine, and the carbon atoms of tht have been omitted for clarity.
(b) Schematic drawing of the polymeric structure of 1. Ag‚‚‚Ag,
Au‚‚‚Ag, Au‚‚‚Au, and Ag-O‚‚‚Ag contacts responsible for the
polymerization are highlighted in purple, blue, orange, and red,
respectively.
Complex 1 crystallizes in the space group P21/n of the
monoclinic system, with two [Au(C6F5)(tht)] units and an
[Ag2(CF3CO2)2] cycle in the asymmetric unit connected through
short metal-metal contacts (Figure 1). Au(1) is bonded to both
silver atoms of the [Ag2(CF3CO2)2] fragment in the asymmetric
unit and also to Au(2), with Au-Ag and Au-Au bond distances
of 2.8792(5) and 2.9029(5) Å, and 3.0845(3) Å, respectively,
all intermetallic contacts being unsupported. By contrast, Au-
(2) is bonded to Au(1) and to only one silver center of a
neighboring dimetallacycle (via the 21 screw axis) with an Au-
Ag distance of 2.8963(6) Å. This last interaction is bridged by
the ipso carbon atom of the aryl group bonded to Au(2) (Ag-C
) 2.684(6) Å), although this fact does not influence the
intermetallic distance. These are in general comparable to those
found in the related derivatives [AuAg4(mes)(CF3CO2)4(tht)]n
(mes ) mesityl) (2.8226(4) and 2.8993(4) Å), [AuAg4(mes)(CF3-
CF2CO2)4(tht)3]n (2.8540(6), 2.8845(6), and 3.0782(6) Å), {-
[AuAg4(mes)(CF3CO2)4(tht)(H2O)]‚H2O‚CH2Cl2}n (2.8505(6),
2.8708(6), and 3.1347(7) Å),7e or (NBu4)2[Au(3,5-C6F3Cl2)2-
Ag4(CF3CO2)5] (2.9010(6)-3.0134(6) Å)7f and longer than in
Figure 3. Asymmetric unit of the crystal structure of complex 2
(30% probability level) with the labeling scheme of the atom
positions. Hydrogen atoms have been omitted for clarity.
[AuAg4(mes)(CF3CF2CO2)4(tht)]n (2.8140(8) and 2.8166(8) Å)7e
or in most of the complexes containing aryl bridging ligands
between gold and silver (2.7758(8)-2.8245(6) Å).7
The Ag(I) atoms of the dimeric [Ag2(CF3CO2)2] unit display
an Ag‚‚‚Ag contact of 2.8963(6) Å, similar to those found in
most analogous structures of complexes of the type [Ag2-
(RCO2)2Ln] (n ) 1, 2) (from 2.8669(9) to 3.3813(6) Å)13 but
slightly shorter than those described in the related mesityl
derivatives [AuAg4(mes)(RCO2)4(tht)x]n (R ) CF3, x ) 1; R )

5934 Organometallics, Vol. 26, No. 24, 2007
Ferna´ndez et al.
Figure 4. (a) One-dimensional structure of complex 2. Hydrogen,
chlorine, and fluorine atoms have been omitted for clarity. (b)
Schematic drawing of the polymeric structure of 2. Au‚‚‚Ag,
Ag‚‚‚Ag, and Ag-O‚‚‚Ag contacts responsible for the polymeri-
zation are highlighted in blue, purple, and red, respectively.
Figure 6. (a) One-dimensional structure of complex 3. Hydrogen
and chlorine atoms have been omitted for clarity. (b) Schematic
drawing of the polymeric structure of 3. Au‚‚‚Ag, Ag‚‚‚Ag, and
Au-S‚‚‚Ag contacts responsible for the polymerization are high-
lighted in blue, purple, and yellow, respectively.
The above-mentioned unsupported Au‚‚‚Au and Au‚‚‚Ag
interactions are responsible for the polymerization of these units
into infinite chains with backbone (-Au2-Au1-Ag2-)n paral-
lel to the y-axis. The chains are interconnected through cross-
links consisting of trifluoroacetates and central, inversion-
symmetric four-membered rings Ag(1)2O(3)2, thus resulting in
a two-dimensional polymer parallel to 101h, as shown in Figure
2. The bridging Ag1-O3#2 distance of 2.382(4) Å is slightly
longer than the Ag-O lengths within the dimeric [Ag(CF3CO2)]2
unit and nearly identical to one of the Ag-O distances (2.398-
(6) Å) found in {[Ag2(CH3CN)2][LIr]2(OTf)2}n (LIr ) [Cp*Ir-
(η4-benzoquinone)]), where Ag2O2 rings are also responsible
for the polymerization of the complex.14
As noted in the Synthesis and Characterization section, the
Au/Ag ratio in 2 is lower than in 1, and thus the asymmetric
unit of the crystal structure of 2 (Figure 3) contains only one
(instead of two) [Au(3,5-C6Cl2F3)(tht)] fragment together with
an [Ag2(CF3CO2)2] ring. These units are connected through
unsupported Au‚‚‚Ag interactions of 2.8784(5) and 3.0221(6)
Å, the latter somewhat longer than in complex 1 (2.8792(5),
2.9029(5), and 2.8963(6) Å) and both of them in general longer
than those observed for other complexes displaying unsupported
Au‚‚‚Ag contacts.8 The Ag-Ag distance within the [Ag2(CF3-
CO2)2] unit is 2.8623(6) Å, slightly shorter than in 1 (2.8963-
(6) Å) and also shorter than in the related Au/Ag mesityl
derivatives [AuAg4(mes)(RCO2)4(tht)x]n (R ) CF3, x ) 1; R )
CF3CF2, x ) 1,3) or {[AuAg4(mes)(CF3CO2)4(tht)(H2O)]‚
H2O‚CH2Cl2}n (2.9149(5)-3.0958(7) Å).7e Thus, the three metal
centers form a nearly equilateral triangle.
Figure 5. Crystal structure of complex 3 (30% probability level)
with the labeling scheme of the atom positions. Hydrogen atoms
have been omitted for clarity.
CF3CF2, x ) 1, 3) or {[AuAg4(mes)(CF3CO2)4(tht)(H2O)]‚
H2O‚CH2Cl2}n (2.9149(5)-3.0958(7) Å).7e
The gold(I) centers display their usual linear environment by
coordination to the ipso carbon atom of an aryl group with
typical Au-C bond lengths of 2.050(6) and 2.039(6) Å and to
the sulfur of a tht molecule with Au-S distances of 2.3260-
(19) and 2.3184(16) Å, shorter than in [AuAg4(mes)(CF3CF2-
CO2)4(tht)3]n (2.3423(16) Å) or in {[AuAg4(mes)(CF3CO2)4-
(tht)(H2O)]‚H2O‚CH2Cl2}n (2.3386(19) Å),7e where the S-donor
ligand has a similar structural disposition. If the Ag‚‚‚Ag contact
is not considered, each silver center displays a pyramidal
environment (see Table 2) by coordination to Au(1) and two
oxygen atoms of the trifluoroacetate anions with Ag-O
distances in the range 2.258(5)-2.339(4) Å. The pyramidal
geometry within the asymmetric unit is extended to distorted
tetrahedral by the additional bonds Au2‚‚‚Ag2#1 and Ag1-
O3#2 (see below).
(13) (a) Powell, J.; Horvath, M. J.; Lough, A.; Phillips, A.; Brunet, J. J.
Chem. Soc., Dalton Trans. 1998, 637. (b) Che, C.-M.; Tse, M-C.; Chan,
M. C. W.; Cheung, K.-K.; Phillips, D. L.; Leung, K.-H. J. Am. Chem. Soc.
2000, 122, 2464. (c) Tsuchiya, T.; Shimizu, T.; Hirabayashi, K.; Kamigata,
N. J. Org. Chem. 2002, 67, 6632. (d) Brandys, M. C.; Puddephatt, R. J. J.
Am. Chem. Soc. 2002, 124, 3946. (e) Brammer, L.; Burgard, M. D.;
Eddleston, M. D.; Rodger, C. S.; Rath, N. P.; Adams, H. Cryst. Eng.
Commun. 2004, 44, 239. (f) Djordjevic, B.; Schuster, O.; Schmidbaur, H.
Inorg. Chem. 2005, 44, 673. (g) Zhong, J. C.; Munakata, M.; Maekawa,
M.; Kuroda-Sowa, T.; Suenaga, Y.; Konaka, H. Inorg. Chim. Acta 2003,
342, 202. (h) Schultheiss, N.; Powell, D. R.; Bosch, E. Inorg. Chem. 2003,
42, 5304. (i) Bosch, E.; Barnes, C. L. Inorg. Chem. 2002, 41, 2543. (j)
Awaleh, M. O.; Badia, A.; Brisse, F.; Bu, X.-H. Inorg. Chem. 2006, 45,
1560.
The [Au(3,5-C6Cl2F3)(tht)] unit shows a linear environment
for gold with Au-C and Au-S bond lengths of 2.024(6) and
2.3159(15) Å, respectively, both of them shorter than in complex
1, and the latter also shorter than in the related compounds
[AuAg4(mes)(CF3CF2CO2)4(tht)3]n (2.3423(16) Å) and
{[AuAg4(mes)(CF3CO2)4(tht)(H2O)]‚H2O‚CH2Cl2}n (2.3386(19)
(14) Moussa, J.; Guyard-Duhayon, C.; Boubekeur, K.; Amouri, H.; Yip,
S.-K.; Yam., V. W. W. Cryst. Growth Des. 2007, 7, 962.

Perhalophenyl(tetrahydrothiophene)gold(I) Complexes
Organometallics, Vol. 26, No. 24, 2007 5935
Table 1. Data Collection and Structure Refinement Details for Complexes 1-3
1
2
3
chemical formula
cryst habit
cryst size/mm
cryst syst
space group
a/Å
C24H16Ag2Au2F16O4S2
pale yellow prism
0.25 × 0.25 × 0.15
monoclinic
P21/n
12.432(2)
15.526(3)
16.748(4)
90
92.464(10)
90
3229.69(11)
4
C14H8Ag2AuCl2F9O4S
yellow prism
0.20 × 0.20 × 0.18
triclinic
P1h
10.280(2)
10.444(2)
11.073(2)
97.187(10)
104.066(10)
104.095(10)
1096.84(4)
2
C12H8AgAuCl5F3O2S
colorless tablet
0.20 × 0.16 × 0.07
triclinic
P1h
8.6735(6)
9.4223(6)
12.1291(8)
77.492(3)
73.345(3)
82.557(3)
924.70(11)
2
b/Å
c/Å
R/deg
â/deg
γ/deg
V/Å3
Z
Dc/g cm-3
M
2.769
1346.16
2480
2.806
926.87
856
2.713
755.33
700
F(000)
T/°C
-173
-173
-173
2θmax/deg
µ(Μo KR)/mm-1
no. of reflns measd
no. of unique reflns
Rint
56
56
62
10.506
26 327
7580
0.0490
0.0368
0.0756
480
132
8.874
18 076
5225
0.0452
0.0348
0.0835
328
37
9.851
38 148
5983
0.0223
0.0122
0.0304
226
18
Ra (I > 2σ(I))
wRb (F2, all reflns)
no. of params
no. of restraints
Sc
1.032
1.835
1.040
2.977
1.097
2.229
max. ∆F/e Å-3
b
2
2
2
2
2
2
a R(F)) ∑|| Fo | - |Fc||/∑|Fo|. wR(F2) ) [∑{w(Fo - Fc )2}/∑{w(Fo )2}]0.5; w-1 ) σ2(Fo ) + (aP)2 + bP, where P ) [Fo + 2Fc ]/3 and a and b are
c
2
2
constants adjusted by the program. S ) [∑{w(Fo - Fc )2}/(n - p)]0.5, where n is the number of data and p the number of parameters.
Table 2. Selected Bond Lengths [Å] and Angles [deg] for
Complex 1a
Table 3. Selected Bond Lengths [Å] and Angles [deg] for
Complex 2a
Au(1)-C(1)
Au(1)-S(1)
Au(1)-Ag(1)
Au(1)-Ag(2)
Au(1)-Au(2)
Au(2)-C(11)
Au(2)-S(2)
Au(2)-Ag(2)#1
Ag(1)-O(1)
Ag(1)-O(3)
Ag(1)-O(3)#2
Ag(1)-Ag(2)
Ag(2)-O(2)
Ag(2)-O(4)
Ag(2)-C(11)#3
2.050(6)
2.3260(19)
2.8792(5)
2.9029(5)
3.0845(3)
2.039(6)
2.3184(16)
2.8135(5)
2.258(5)
2.334(4)
2.382(4)
2.8963(6)
2.303(5)
2.339(4)
2.684(6)
Au-C(1)
2.026(6)
2.3158(16)
2.8784(5)
3.0221(6)
2.8623(6)
2.247(4)
2.324(4)
2.401(4)
2.191(4)
2.301(4)
2.390(4)
Au-S
Au-Ag(1)
Au-Ag(2)
Ag(1)-Ag(2)
Ag(1)-O(4)
Ag(1)-O(1)
Ag(1)-O(1)#1
Ag(2)-O(2)
Ag(2)-O(3)
Ag(2)-O(3)#2
C(1)-Au-S
177.58(15)
132.66(17)
98.34(12)
111.38(10)
137.89(19)
116.57(13)
89.13(13)
O(4)-Ag(1)-O(1)
O(4)-Ag(1)-Au
O(1)-Ag(1)-Au
O(2)-Ag(2)-O(3)
O(2)-Ag(2)-Au
O(3)-Ag(2)-Au
C(1)-Au(1)-S(1)
C(11)-Au(2)-S(2)
O(1)-Ag(1)-O(3)
O(1)-Ag(1)-Au(1)
O(3)-Ag(1)-Au(1)
O(2)-Ag(2)-O(4)
O(2)-Ag(2)-Au(1)
O(4)-Ag(2)-Au(1)
174.95(15)
174.93(18)
135.18(17)
96.59(14)
114.67(11)
106.1(2)
a Symmetry transformations used to generate equivalent atoms: #1
-x+1,-y+1,-z; #2 -x+1,-y+1,-z+1.
107.29(13)
115.24(11)
only through Ag-O-Ag bridges between the silver dimers,
forming inversion-symmetric four-membered Ag2O2 rings and
resulting in chains that run parallel to the crystallographic z-axis
(Figure 4). The Ag-O distances responsible for the polymer-
ization, of 2.401(4) and 2.390(4) Å, are longer than those within
the [Ag(CF3CO2)]2 unit (2.191(4) to 2.324(4) Å).
The stoichiometry of complex 3 was unequivocally estab-
lished in its crystal structure, which, as in 1, shows a 1:1 gold:
silver ratio. Nevertheless, the structure is different from that of
complex 1; it crystallizes in the space group P1h with one [Au-
(C6Cl5)(tht)] unit and a half of an [Ag2(CF3CO2)2] cycle in the
asymmetric unit (Figure 5). The gold center in 3 binds only
one silver(I) atom, whereas in 2 there are two Au‚‚‚Ag
interactions, and in 1 two Au‚‚‚Ag and one Au‚‚‚Au contact
are present. The Au-Ag distance of 2.96615(19) Å is longer
than most of the Au-Ag distances in 1 and 2 and also longer
a Symmetry transformations used to generate equivalent atoms: #1
-x+1/2,y-1/2,-z+1/2; #2 -x,-y+2,-z; #3 -x+1/2,y+1/2,-z+1/2.
Å),7e which also contain terminal tht ligands. As in the crystal
structure of compound 1, each Ag(I) center displays a pyramidal
environment without considering the Ag‚‚‚Ag contact (see Table
3) by coordination to a gold center and to two oxygen atoms of
the CF3 anions with Ag-O distances ranging from 2.191(4) to
2.324(4) Å. The coordination geometry is extended to distorted
tetrahedral by the additional Ag-O bonds to other asymmetric
units (see below).
The main difference between this structure and the one
described above for 1 is the absence of aurophilic interactions
in this species, the shortest Au-Au distance being greater than
7 Å. Consequently, the polymerization in this case takes place

5936 Organometallics, Vol. 26, No. 24, 2007
Ferna´ndez et al.
Table 4. Selected Bond Lengths [Å] and Angles [deg] for
Complex 3a
Au-C(1)
Au-S
2.0296(15)
2.3109(4)
2.96615(19)
2.2026(12)
2.2421(12)
2.7033(4)
3.0071(3)
Au-Ag
Ag-O(1)
Ag-O(2)#1
Ag-S#2
Ag-Ag#1
C(1)-Au-S
176.09(4)
159.97(4)
109.91(3)
85.50(3)
O(1)-Ag-O(2)#1
O(1)-Ag-S#2
O(2)#1-Ag-S#2
O(1)-Ag-Au
O(2)#1-Ag-Au
S#2-Ag-Au
92.25(3)
101.92(3)
85.560(10)
122.104(16)
Au-S-Ag#2
a Symmetry transformations used to generate equivalent atoms: #1 -x,-
y,-z+1; #2 -x+1,-y,-z+1.
Figure 7. Emission spectra for complexes 1-3 in the solid state
at room temperature.
than most of the unsupported Au‚‚‚Ag contacts observed for
other complexes.8
Table 5. Spectroscopic and Photophysical Properties of 1-3
complex
medium (T [K])
λem (λexc) [nm]/τ (µs)
The gold(I) atom is again linearly coordinated to the ipso
carbon atom of an aryl group with a typical Au-C bond length
of 2.0296(15) Å and to the sulfur of a tht molecule with an
Au-S distance of 2.3109(4) Å. A significant difference between
the crystal structure of 3 and those described for 1 and 2 is that
the sulfur atom of the tht in 3 acts as electron density donor
not only to a Au(I) center of the [Au(C6Cl5)(tht)] unit but also
to an Ag(I) atom of an adjacent [Ag2(CF3CO2)2] dimer, thus
forming, together with the Au‚‚‚Ag contacts, hexanuclear Ag2-
Au2S2 rings (see Figure 6) similar to those recently reported by
us in complexes [AuAg4(mes)(RCO2)4(tht)]n (R ) CF3, CF3-
CF2).7e However, the Au-S bond length is shorter than in both
mesityl derivatives (2.3195(11) Å for R ) CF3, 2.347(2) Å for
R ) CF3CF2) or in other complexes with gold(I) bonded to a
terminal tht (2.237-2.335(6) Å),15 slightly shorter than in
complex 1 (2.3260(19) and 2.3184(16) Å), and similar to that
in 2 (2.3159(15) Å), although in these last cases the tht molecule
acts as a terminal instead of a bridging ligand and a stronger
interaction would be expected. The Ag-S distance of 2.7033-
(4) Å is in this case shorter than in [AuAg4(mes)(CF3CF2CO2)4-
(tht)]n (2.888(2) Å),7e but longer than in other complexes, such
as [AuAg4(mes)(CF3CO2)4(tht)]n (2.6877(11) Å),7e [Ag4(CF3-
CO2)4(tht)2] (2.4420(8) Å),7e [Ag(O3SCF3)(SC4H8)]n16 (2.4897-
(9) and 2.4963(9) Å), and [{(Ph3P)Au(µ-mes)Ag(SC4H8)}2][SO3-
1
CH2Cl2 (77)
solid (298)
solid (77)
CH2Cl2 (77)
solid (298)
solid (77)
485 (390)
473 (378)/8.3
430, 480 (385)/11.6, 12.1
495 (370)
570 (410)/7.9
590 (490)
2
3
CH2Cl2 (77)
solid (298)
505 (350)
447 (307)/57.0
564 (423) pressure
495 (300)
solid (77)
550 (405) pressure
Table 6. Spectroscopic and Photophysical Properties of Gold
Precursors
complex
medium (T [K])
λ
em (λexc) [nm]
[Au(C6F5)(tht)]
CH2Cl2 (77)
solid (298)
solid (77)
CH2Cl2 (77)
solid (298)
solid (77)
CH2Cl2 (77)
solid (298)
solid (77)
482 (370)
414 (300)
460 (360)
484 (370)
428 (300)
443 (360)
481 (380)
467 (300)
477 (363)
[Au(C6F3Cl2)(tht)]
[Au(C6Cl5)(tht)]
three complexes, but not in the solid state. Thus, for example,
the experimental emission values for compounds 1-3 in
dichloromethane at 77 K appear in the same region of energy,
at 485 (exc. 390) for 1, 495 (exc. 370) for 2, and 505 (350 nm)
for 3, similar also to the three precursor gold complexes [AuR-
(tht)], which show emissions at 485 (exc. 370; R ) C6F5), 495
(exc. 370; R ) C6Cl2F3), and 505 nm (exc. 380; R ) C6Cl5)
(Table 6).
By contrast, the mixed-metal complexes and the gold precur-
sors show different emissions in the solid state. In the latter, a
bathochromic shift is observed at room temperature as the
electronegativity of the aryl substituents decreases (Table 6),
but for complexes 1-3 (see Figure 7) the same sequence is not
observed, suggesting different origins. In addition, complex 1
displays two emissions at 77 K, which is not observed for the
rest of the derivatives or for complex 3, whose emission is red-
shifted under pressure to 564 nm, a fact that could be related to
a phase exchange.17 The lifetimes of the emissions in the solid
state at room temperature are in the microsecond range,
suggesting phosphorescent processes in all cases.
7a
CF3]2 (2.8245(6) Å).
As in the crystal structures of 1 and 2, the Ag(I) atoms of
the dimeric [Ag2(CF3CO2)2] units in 3 show Ag‚‚‚Ag contacts
of 3.0071(3) Å, weaker than in 1 and 2. The Ag-O distances
within the dimer, of 2.2026(12) and 2.2421(12) Å, are compa-
rable to those found in complexes 1 and 2. The trifluoroacetate
anions and the argentophilic contacts link neighboring Ag2Au2S2
rings, leading to the formation of a monodimensional polymer
parallel to the x-axis, as shown in Figure 6.
Optical Properties. All the presented gold-silver complexes
are luminescent in solid state at room temperature and at 77 K
or in frozen solutions (dichloromethane or acetone) (see Table
5). The optical behavior in frozen solution is similar for the
(15) (a) Ahrland, S; Noren, B.; Oskarsson, A. Inorg. Chem. 1985, 24,
1330. (b) Friedrichs, S.; Jones. P. G. Acta Crystallogr., Sect. C: Cryst.
Struct. Commun. 2000, 56, 56. (c) Lo´pez de Luzuriaga, J. M.; Schier, A.;
Schmidbaur, H. Chem. Ber. 1997, 130, 647. (d) Ahrens, B.; Jones, P. G. Z.
Naturforsch., B: Chem. Sci. 2000, 55, 803. (e) Ahrland, S.; Dreisch, K.;
Noren, B. Oskarsson, A. Mater. Chem. Phys. 1993, 35, 281. (f) Abdou, H.
E.; Mohammed, A. A.; Fackler, J. P., Jr. Inorg. Chem. 2005, 44, 166.
(16) Bardaj´ı, M.; Crespo, O.; Laguna, A.; Fischer, A. K. Inorg. Chim.
Acta 2000, 304, 7.
(17) (a) Moses, D.; Feldblum, A.; Ehrenfreund, E.; Heeger, A. J.; Chung,
T. C.; MacDiarmid, A. G. Phys. ReV. B 1982, 26, 3361. (b) Zhao, X.;
Schroeder, J.; Bilodeau, T. G.; Hwa, L. Phys. ReV. B 1989, 40, 1257.

Perhalophenyl(tetrahydrothiophene)gold(I) Complexes
Organometallics, Vol. 26, No. 24, 2007 5937
the influence of these groups in the transitions responsible for
the emissions.
The fact that the luminescence in the solid state is different
for complexes 1-3 seems to be related to the different number
and types of metal-metal interactions that appear in the
complexes. For instance, while complex 1 shows one
Au(I)‚‚‚Au(I) and two Au(I)‚‚‚Ag(I) interactions, complex 2
displays just two Au(I)‚‚‚Ag(I) and complex 3 shows only one
Au(I)‚‚‚Ag(I) interaction. Therefore the presence in the solid
state at 77 K for complex 1 of two emissions at 430 and 480
nm could be related to the two different types of metallophilic
interactions. Both of them have lifetimes of ca. 12 µs, in
accordance with emissions arising from states of triplet parent-
age. Thus, we have carried out TDDFT calculations of the two
lowest triplet excitations on a simplified model system, [Au2-
Ag2(C6F5)2(CF3CO2)2(tht)2], which includes all the metal-metal
interactions. In this way we can estimate the orbitals involved
in the transitions responsible for the luminescence observed for
1. The lowest triplet excitation T1 involves HOMO and LUMO
orbitals that display a (pentafluorophenyl-gold)2 character and
gold-silver character, respectively (Figure 9). Therefore, this
transition can be considered as a charge transfer between the
Au(C6F5) groups and the metal centers. In this regard, a similar
result was obtained for Au2M2 (M ) Ag, Cu) tetranuclear
systems, in which the presence of two adjacent gold centers
contributes jointly to the origin of the electronic transition, the
heterometals bonded to them acting as receptors for this
electronic density.18 The second lowest triplet excitation T2
involves mainly orbitals HOMO-3 and HOMO-5 as occupied
orbitals with a high contribution from the pentafluorophenyl
and trifluoroacetate groups and LUMO orbital which is placed
at the metal centers. In this case ligands to metal charge transfer
is suggested (see Supporting Information). Previously reported
studies on luminescent Au-Ag complexes point out that the
presence of metal-metal interactions influences the emission
energies, intensities, and behavior at different temperatures of
the isolated derivatives.19
Figure 8. Theoretical model systems [Au2Ag2(C6F5)2(CF3CO2)2-
(tht)2] (1a) and [AuAg2(C6F3Cl2)2(CF3CO2)2(tht)] (2a).
Figure 9. Most important contributions to the lowest triplet
transitions (T1) for model systems [Au2Ag2(C6F5)2(CF3CO2)2(tht)2]
(1a) and [AuAg2(C6F3Cl2)2(CF3CO2)2(tht)] (2a).
We have also carried out DFT and TDDFT calculations on
simplified model systems for complexes 1-3. For complex 1
we have chosen the model [Au2Ag2(C6F5)2(CF3CO2)2(tht)2] (1a),
and for complexes 2 and 3 we have used model systems
[AuAg2R(CF3CO2)2(tht)] (R ) C6F3Cl2 (2a) and C6Cl5 (2b))
(Figure 8). In all cases we have included all the metallophilic
interactions observed experimentally. From DFT calculations
the nature of the frontier orbitals can be analyzed. In general,
the highest occupied molecular orbitals are mostly placed at
the perhalophenyl groups with some contribution from the gold
centers, especially for model 1a, in which a gold‚‚‚gold
interaction is involved. The lowest unoccupied molecular orbitals
are mainly located at gold and silver centers (see Supporting
Information).
TDDFT calculations permit an estimate of the energy of the
lowest triplet excitations and the orbitals that contribute to them.
For model 1a we have calculated the two lowest triplet
excitations since two phosphorescent emissions are observed
experimentally. Thus, the calculated energy for T1 is 380 nm
and for T2 is 369 nm, meanwhile the observed excitation spectra
for complex 1 at room temperature displays a band at 385 nm,
in agreement with the theoretical results. We have also
calculated the lowest triplet excitation for models 2a and 3a,
displaying theoretical values of 385 and 406 nm, in close
agreement with the experimental values of 410 and 423 nm,
respectively (Figure 9). As we can observe, such theoretical
excitations as the experimental ones follow the same trend in
energy (1 > 2 > 3) in accordance with the higher attracting
abilities of C6F5 > C6F3Cl2 > C6Cl5 groups, indicating, perhaps,
In the case of the other two complexes, 2 and 3, the triplet
transition shows a similar charge transfer character from the
Au(C6F5) unit to the metals. In this case the observation of a
single triplet emission can be in accordance with the presence
of Au(I)‚‚‚Ag(I) interactions and the absence of Au(I)‚‚‚Au(I)
ones and in agreement with the experimental one (Figure 9).
According to these results, it seems plausible that, in addition
to the triplet emission that appears as a consequence of the
Au‚‚‚Ag interaction, when an additional aurophilic interaction
is present (e.g., complex 1), both gold centers cooperatively
contribute to another, different transition to the acidic silver
atom(s), leading to another triplet emission.
It is worth mentioning that these theoretical model systems,
which include the repetition units of the extended structures of
1-3, give a qualitative explanation of the photophysical
properties in the solid state, although the calculations on tetra-
(18) Ferna´ndez, E. J.; Laguna, A.; Lo´pez-de-Luzuriaga, J. M.; Monge,
M.; Montiel, M.; Olmos, M. E.; Rodr´ıguez-Castillo, M. Organometallics
2006, 25, 3639.
(19) (a) Ferna´ndez, E. J.; Laguna, A.; Lo´pez-de-Luzuriaga, J. M. Dalton
Trans. 2007, 1969. In particular, the following gives an example of the
luminescence thermochromism due to the Au‚‚‚Ag interactions present: (b)
Mohammed, A. A.; Burini, A.; Fackler, J. P., Jr. J. Am. Chem. Soc. 2005,
127, 5012. The following reports an example of enhanced intensity of the
emissions due to the presence of Au‚‚‚Ag interactions: (c) Catalano, V. J.;
Malwitz, M. A.; Etogo, A. O. Inorg. Chem. 2004, 43, 5714. (d) Wang,
Q.-M.; Lee, Y.-A.; Crespo, O.; Deaton, J.; Tang, C.; Gysling, H. J.; Gimeno,
M. C.; Larraz, C.; Villacampa, M. D.; Laguna, A.; Eisenberg, R. J. Am.
Chem. Soc. 2004, 126, 9488.

5938 Organometallics, Vol. 26, No. 24, 2007
Ferna´ndez et al.
complexes [AuR(tht)] (R ) C6F5, C6Cl2F3,C6Cl5) were obtained
according to literature procedures.22
and trinuclear compounds may not reflect the electronic
structures for the more highly associated systems in the solid
state. In this regard, complex 2 shows a very low-energy
emission compared to those observed for complexes 1 and 3.
Although the calculations point out the same type of orbitals
as responsible for the transition that leads to the emissions, the
reason for this difference could be related to the different
extended structures observed in the solid state. Thus, while in
the case of complexes 1 and 3 the [Au(C6X5)(tht)] units are
involved in the extension of the structures through additional
Au(I)‚‚‚Au(I) (1) and S‚‚‚Ag (2) interactions in complex 2, the
[Au(C6X5)(tht)] units act as donors only through the gold
centers. In fact, very different emissions in compounds with
the same perhalophenyl groups, metal atoms, and ancillary
ligands have been recently reported and justified in terms of
the very different structural arrangements found in the solid
state.20
Synthesis of [AuAg(C6F5)(CF3CO2)(tht)]n (1). To a solution
of [Au(C6F5)(tht)] (0.090 g, 0.2 mmol) in diethyl ether (20 mL)
was added [Ag(CF3CO2)] (0.044 g, 0.2 mmol). After 30 min of
stirring the solution was concentrated under vacuum to ca. 5 mL.
Addition of n-hexane (10 mL) led to precipitation of complex 1 as
a white solid. Yield: 0.110 g (81.9%). Anal. (%) Calcd for 1 (C12H8-
AuAgF8O2S): C 21.41, H 1.20, S 4.76. Found: C 21.35, H 1.20,
S 4.61. 1H NMR (75.5 MHz, CDCl3, ppm): δ 3.44 (m, 4H,
S-CH2-CH2-) and 2.21 (m, 4H, S-CH2-CH2-). 19F NMR
(282.4 MHz, CDCl3, ppm): δ -115.6 (m, 2F, Fo), -157.7 (t, 1F,
3
Fp, J(Fp-Fm) ) 18.4 Hz), -162.0 (m, 2F, Fm), -73.1 (s, 3F,
CF3CO2-). (MALDI-TOF -): m/z 865 ([Ag3(CF3CO2)4(tht)]-
100%), 531 ([Au(C6F5)2]- 52%). FT-IR (Nujol): ν(C6F5) at 1504,
981 and 796 cm-1, ν(tht) at 1264 cm-1 and ν(CF3CO2) at 1627
and 1192 cm-1
.
Synthesis of [AuAg2(C6Cl2F3)(CF3CO2)2(tht)]n (2). A solution
of [Au(C6Cl2F3)(tht)] (0.097 g, 0.2 mmol) and [Ag(CF3CO2)] (0.088
g, 0.4 mmol) in dichloromethane (20 mL) was stirred for 30 min.
The colorless solution was concentrated under vacuum to ca. 5 mL.
Addition of n-hexane (10 mL) was added to precipitate complex 2
as a pale yellow solid. Yield: 0.162 g (87.3%). Anal. (%) Calcd
for 2 (C14H8 AuAg2Cl2F9O4S): C 18.14, H 0.87, S 3.45. Found:
The behavior in solution is completely different since, as we
have commented on, the complexes 1-3 and the gold precursors
show similar emission energies at 77 K in dichloromethane,
but at room temperature none of them show luminescence. This
fact could be related to the rupture of the metal-metal
interactions in solution, which are responsible for the lumines-
cent behavior in the solid state and are not recovered even at
77 K. An increase of the concentrations for the three complexes
does not affect the luminescence energy, and only an increase
of the intensity of the emissions is observed, which is indicative
of the absence of aggregation in solution.
1
C 17.99, H 0.93, S 3.29. H NMR (75.5 MHz, CDCl3, ppm): δ
3.42 (m, 4H, S-CH2-CH2-) and δ 2.21 (m, 4H, S-CH2-CH2-
). 19F NMR (282.4 MHz, CDCl3, ppm): δ -89.8 (s, 2F, Fo),
-115.92 (s, 1F, Fp) and -73.1 (s, 3F, CF3CO2-). (MALDI-TOF
-): m/z 997 ([Au2(C6Cl2F3)3]-, 27%), 865 ([Ag3(CF3CO2)4(tht)]-,
13%), 597 ([Au(C6Cl2F3)2]-, 100%). FT-IR (Nujol): ν(C6Cl2F3)
at 1586, 1556, 1061, and 771 cm-1, ν(tht) at 1255 cm-1, and ν(CF3-
CO2) at 1647 and 1204 cm-1
.
The trend of the emissions in solution is consistent with a
lower energy difference in the HOMO-LUMO gap as the
electronegativity of the perhalophenyl substituents decrease
(C6F5 > C6F3Cl2 > C6Cl5), and therefore, these transitions are
likely to be related to ππ* transitions at the perhalophenyl
groups or charge transfer transitions between these groups and
the gold center. The possibility of the tht ligand being
responsible for this luminescent behavior can be ruled out since
it is luminescent at a different energy (400 nm) as a consequence
of a n f σ* transition.21
Synthesis of [AuAg(C6Cl5)(CF3CO2)(tht)]n (3). To a diethyl
ether (20 mL) solution of [Au(C6Cl5)(tht)] (0.107 g, 0.2 mmol) was
added [Ag(CF3CO2)] (0.044 g, 0.2 mmol). The solution turned pale
yellow, and a solid started to precipitate. After 30 min of stirring
the solution was concentrated under vacuum to ca. 5 mL. Addition
of n-hexane (10 mL) led to precipitation of complex 3 as a white
solid. Yield: 0.106 g (70.1%). Anal. (%) Calcd for 3 (C12H8
AuAgCl5F3O2S): C 19.08, H 1.07, S 4.24. Found: C 19.06, H 0.91,
S 3.81. 1H NMR (75.5 MHz, CDCl3, ppm): δ 3.20 (m, 4H,
S-CH2-CH2-) and δ 2.20 (m, 4H, S-CH2-CH2-). 19F NMR
(282.4 MHz, CDCl3, ppm): δ -73.0 (s, 3F, CF3CO2-). (MALDI-
TOF -): m/z 1140 ([Au2(C6Cl5)3]- 10%), 694 ([Au(C6Cl5)2]-
100%). FT-IR (Nujol): ν(C6Cl5) at 843 and 628 cm-1, ν(tht) at
Experimental Section
1256 cm-1, and ν(CF3CO2) at 1643 and 1202 cm-1
.
Instrumentation. Infrared spectra were recorded in the 4000-
200 cm-1 range on a Nicolet Nexus FT-IR using Nujol mulls
between polyethylene sheets. C, H, S analyses were carried out
with a Perkin-Elmer 240C microanalyzer. MALDI-TOF spectra
were recorded in a Microflex MALDI-TOF Bruker spectrometer
operating in the linear and reflector modes using dithranol as matrix.
1H and 19F NMR spectra were recorded on a Bruker ARX 300 in
CDCl3 solutions. Chemical shifts are quoted relative to SiMe4 (1H,
external) and CFCl3 (19F, external). Excitation and emission spectra
were recorded with a Jobin-Yvon Horiba Fluorolog 3-22 Tau-3
spectrofluorimeter. Phosphorescence lifetime was recorded with a
Fluoromax phosphorimeter accessory containing a UV xenon flash
tube with a flash rate between 0.05 and 25 Hz. The lifetime data
were fitted using the Jobin-Yvon software package and the Origin
6.1 program.
Crystallography. The crystals were mounted in inert oil on glass
fibers and transferred to the cold gas stream of a Nonius Kappa (1
and 2) or a Bruker APEX2 (3) CCD area-detector diffractometer
equipped with an Oxford Instruments low-temperature attachment.
Data were collected by graphite-monochromated Mo KR radiation
(λ ) 0.71073 Å). Scan type: ω and φ. Absorption corrections:
numerical (based on multiple scans). The structures were solved
by direct methods and refined on F2 using the program SHELXL-
97.23 All non-hydrogen atoms were anisotropically refined (with
the exception of the fluorine atoms of the disordered CF3 groups
in 1 and 2), and hydrogen atoms were included using a riding model.
Further details on the data collection and refinement methods can
be found in Table 1. Selected bond lengths and angles are shown
in Tables 2-4, and crystal structures of 1-3 can be seen in Figures
1-6. CCDC-652861-652863 contain the supplementary crystal-
lographic data for this paper. These data can be obtained free of
General Comments. Silver trifluoroacetate is commercially
available and was purchased from Sigma-Aldrich. The precursor
(22) (a) Uso´n, R.; Laguna, A.; Vicente, J. J. Chem. Soc., Chem. Commun.
1976, 353. (b) Casado, A. L.; Espinet, P. Organometallics 1998, 17, 3677.
(c) Uso´n, R.; Laguna, A.; Vicente, J.; Garc´ıa, J.; Bergareche, B. J.
Organomet. Chem. 1979, 173, 349.
(23) Sheldrick, G. M. SHELXL-97; University of Go¨ttingen: Go¨ttingen,
Germany, 1997.
(20) Ferna´ndez, E. J.; Laguna, A.; Lo´pez-de-Luzuriaga, J. M.; Olmos,
M. E.; Pe´rez, J. Dalton Trans. 2004, 1801.
(21) Unpublished results

Perhalophenyl(tetrahydrothiophene)gold(I) Complexes
Organometallics, Vol. 26, No. 24, 2007 5939
charge via www.ccdc.cam.ac.uk/conts/retrieving.html (or from the
Cambridge Crystallographic Data Centre, 12 Union Road, Cam-
bridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail:
deposit@ccdc.cam.ac.uk).
perturbation theory approach (TD-DFT),26 which is a DFT gener-
alization of the Hartree-Fock linear response (HF-LR) or random-
phase approximation (RPA) method.27 In all calculations, the
Karlsruhe split-valence quality basis sets28 augmented with polar-
ization functions29 were used (SVP). The Stuttgart effective core
potential in TURBOMOLE was used for Au and Ag.30
Special Details. In complexes 1 and 2 one of the carbon atoms
of a tht molecule (C(8) in 1 and C(9) in 2) is disordered over two
different positions (55:45). Both CF3 groups in 1 and one of them
in 2 are highly disordered, and the positions of their fluorine atoms
have been modeled to a tetrahedral geometry and refined isotro-
pically.
Acknowledgment. This work was supported by the DGI-
(MEC)/FEDER (CTQ2004-05495). R.C.P. thanks MEC for a
grant.
Supporting Information Available: CIF files and TD-DFT
results. This material can be obtained, free of charge, via the Internet
at http://pubs.acs.org.
Computational Details. The model systems used in the theoreti-
calstudiesof[Au2Ag2(C6F5)2(CF3CO2)2(tht)2](1a)and[AuAg2R2(CF3-
CO2)2(tht)] (R ) C6F3Cl2 (2a) and C6Cl5 (3a)) were taken from
the X-ray diffraction data for complexes 1, 2, and 3, respectively.
Keeping all distances, angles, and dihedral angles frozen, single-
point DFT calculations were performed on model systems. In both
the ground-state calculations and the subsequent calculations of the
electronic excitation spectra, the B3LYP functional24 as imple-
mented in TURBOMOLE25 was used. The excitation energies were
obtained at the density functional level by using the time-dependent
OM700701M
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