Liquid-crystalline, polycatenar complexes of silver(I): Dependence of the mesomorphism on the ligand and the anion

Article abstract of DOI:10.1039/a809320b

We have synthesised several series of poly(alkoxy)stilbazole ligands, and investigated the thermal behaviour of their complexes with some silver salts. Most of the complexes, with the general formula [AgL₂][X], where X = dodecyl sulfate (DOS) or trifluoromethanesulfonate (OTf), and L = poly(alkoxy)stilbazole, were found to be liquid-crystalline over a wide- temperature range, the vast majority of them being low-melting. The mesomorphic properties were mainly dominated by the formation of hexagonal columnar (Col(h)) phases and to a lesser extent, of bicontinuous Ia3d cubic phases; monotropic nematic and smectic C phases were also seen for one structural type of compound only. The mesophases were assigned on the basis of their optical textures under polarised optical microscope (POM) prior to being identified by X-ray diffraction (XRD). The temperatures and enthalpies of the transitions were determined by differential scanning calorimetry (DSC). The mesomorphism was found to be strongly dependent on the substitution pattern of the ligand, that is on the number, position and length of alkoxy chains, as well as on the type of the counter anion. We explain the mesomorphism in terms of ionic interactions and in terms of mean interfacial curvature between the hydrophobic, aliphatic chains and the rigid, aromatic, central core, by analogy to lyotropic systems.

Full text of DOI:10.1039/a809320b

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Liquid-crystalline, polycatenar complexes of silver(I): dependence of
the mesomorphism on the ligand and the anion
Bertrand Donnio¤ and Duncan W. Bruce*
School of Chemistry, University of Exeter, Stocker Road, Exeter, UK EX4 4QD.
E-mail: d.bruce=exeter.ac.uk
Received 30th November 1998, Accepted 7th January 1999
We have synthesised several series of poly(alkoxy)stilbazole ligands, and investigated the thermal behaviour of their
complexes with some silver salts. Most of the complexes, with the general formula [AgL ][X], where X \ dodecyl
2
sulfate (DOS) or triÑuoromethanesulfonate (OTf), and L \ poly(alkoxy)stilbazole, were found to be
liquid-crystalline over a wide-temperature range, the vast majority of them being low-melting. The mesomorphic
properties were mainly dominated by the formation of hexagonal columnar (Col ) phases and to a lesser extent, of
h
bicontinuous Ia3d cubic phases; monotropic nematic and smectic C phases were also seen for one structural type of
compound only. The mesophases were assigned on the basis of their optical textures under polarised optical
microscope (POM) prior to being identiÐed by X-ray di†raction (XRD). The temperatures and enthalpies of the
transitions were determined by di†erential scanning calorimetry (DSC). The mesomorphism was found to be
strongly dependent on the substitution pattern of the ligand, that is on the number, position and length of alkoxy
chains, as well as on the type of the counter anion. We explain the mesomorphism in terms of ionic interactions and
in terms of mean interfacial curvature between the hydrophobic, aliphatic chains and the rigid, aromatic, central
core, by analogy to lyotropic systems.
possess a common denominator, in that they are amphiphilic
in nature. Indeed, all the molecules listed above are made of
Introduction
For many years, thermotropic cubic phases were scarcely
studied, essentially due to their rare appearance in conven-
tional liquid-crystalline materials,1 and thus, very little infor-
mation was known about their structure. More recently, they
have been more extensively studied. The two general types of
cubic phases2,3 commonly found in lyotropic systems are now
being observed in many thermotropic systems. For instance,
micellar thermotropic cubic phases (analogous to the lyotro-
pic I and I phases) have been undoubtedly identiÐed in
some dendrimeric macromolecules,4 in several mesogens con-
taining a carbohydrate or a polyhydroxy moiety,5 and also,
most probably, in some polar, globular mesogens.6 Bicon-
tinuous thermotropic cubic phases (analogous to the lyotropic
two (or more) di†erent constituent blocks which are structur-
ally and chemically di†erent.
The concept of amphiphilicity and liquid-crystallinity was,
for a long time, used exclusively to describe the behaviour of
lyotropic liquid crystal systems. More recently, the amphi-
philic character of thermotropic mesogens has been taken into
account and is felt to be a very important driving force for
thermotropic mesophase formation.18 Consequently, it is now
common to remark on the similarities in the mesomorphism
of thermotropic and lyotropic mesogens, rather than look to
the di†erences. This approach, developed in two major
papers18 which emphasise the amphipatic character of the
molecules, should progressively set up the foundation of a new
concept unifying the description of mesophases on the one
hand, and leading to enhanced understanding of phase forma-
tions and transitions based on the evolution of the shape of
the interfaces on the other. This concept has been the subject
of an updated comprehensive review recently published, which
highlights the importance of micro-segregation in non-
conventional mesogens, and further extends the essential role
of amphipathy in liquid crystals.19
Indeed, an important property of amphiphilic molecules,
due to the di†erent nature of their block units, is the ability to
organise to form structures which divide the space into sub-
spaces with di†erent properties, the di†erent sub-spaces thus
being separated by interfaces. The degree of amphiphilic char-
acter, in addition to the degree of molecular anisometry, will
inÑuence the micro-segregation and a†ect the shape of the
surface (interface) separating the di†erent parts of the mol-
ecules. Bearing this in mind, a lamellar phase can, therefore,
be described as a succession of planar surfaces, and a colum-
nar phase as a two-dimensional arrangement of cylindrical
surfaces. However, since this is purely a geometrical approach,
care must be taken as these interfaces are not so precise and
well-deÐned, and in addition to thermal agitation, di†usion
1
2
V
phase) have been observed in some more conventional
2
systems, for instance in calamitic systems such as the 4-
alkoxy-3-nitro- (or -cyano) biphenyl-4@-carboxylic acids and
1,2-bis(4-alkoxybenzoyl)hydrazine,7 disc-like compounds such
as the hexa-O-pentanoylscyllo inositol and a few derivatives of
the ellagic acids,8 as well as in polyol and carbohydrate liquid
crystals,5a,9 silver stilbazole complexes,10 polycatenar and bi-
swallow-tailed mesogens,11 dialkylphosphate salts,12 oli-
goalkylene amides,13 rod-coil calamitic mesogens14 and,
probably, in some silver thiolate complexes.15 Other meso-
morphic systems have been found to form cubic phases in the
melt, such as diblock co-polymers16 in which the mesophases
occur as a function of the volume fraction of the two blocks,
and polyelectrolyteÈsurfactant systems.17 With such a variety
of molecular structures, it is not straightforward to predict the
occurrence of these three-dimensional mesophases and thus,
the possibility for molecular design remains low. However,
one can notice that most of the compounds listed above
¤ Present address: Institut fur Makromolekulare Chemie, Albert-
Ludwigs Universitat, Hermann-Staudinger-Haus, Stefan Meier
Strasse 31, Freiburg i. Br., 79104, Germany.
New J. Chem., 1999, 275È286
275

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occurs so that the interfaces can be modulated (smectic) or
undulating (columnar), i.e. the interfaces are not planar, rather
curved with a wave-like periodicity (see e.g. refs 11a and 12c).
Furthermore, transitions from smectic or columnar organis-
ation to nematic phases can be explained by molecular di†u-
sion from adjacent lamellar planes (S-to-N), or adjacent
columns (Col-to-N) until the interfaces have totally vanished.
In the last 15 years, there has been a growing attraction to
the study of metallomesogens, as evidenced by an abundant
literature.20 This interest arose because of the new properties
that may be expected on the introduction of metals into
liquid-crystalline materials. In addition, metals o†er wider
possibilities for structural variations (coordination, geometry)
than simple organic molecules, and a large number of metalÈ
ligand combinations can be envisaged to generate meso-
morphic materials.20 Another interesting aspect is the search
for the establishment of well deÐned structureÈproperty
relationships in order to be able to predict liquid-crystalline
properties in metallomesogens, as well as to enrich our under-
standing of phase formation and molecular organisation, since
additional parameters than those considered in organic liquid
crystals may have to be taken into account. Many such
studies have already been undertaken,20 and, in particular, an
important part of our work has concentrated on the silver(I)
complexes of alkoxystilbazoles.11,20b,21 In a previous study,
we described the mesomorphism of some bis(3,4-di-
alkoxystilbazole)silver(I) alkyl sulfate complexes, and were
particularly interested in determining the factors governing
the formation of the cubic mesophases present in these
systems.11a,21 A part of this work consisted of varying the
length of the alkyl sulfate anion only, and we remarked that
the mesophase range and type were dependent on whether or
not the (alkyl sulfate) alkyl chain crossed the aliphatic/
aromatic interface.21 This was explained in terms of contribu-
tion (or not) of the anion alkyl chain to the molecular chain
area, resulting in the modiÐcation (increase) of the aliphatic/
aromatic ratio, and hence, of the degree of curvature at the
coreÈchain interface. Thus, a possible way to obtain meso-
morphic materials with ““curved mesophasesÏÏ (cubic and
columnar phases) is to vary the aliphatic/aromatic ratio of
amphiphilic molecules in order to modify the associated inter-
face, by analogy with the lyotropic mesophases. As was pre-
viously shown,11a this can be achieved, for example, by
grafting more than one peripheral chain on the mesogen,
which can be approximated, in some ways, to the addition of
an apolar solvent to amphiphilic molecules. We now report a
further development of this work in which we focus primarily
on the structure of the ligand, and thus, we have synthesised
Ðve more series of polysubstituted stilbazoles in order to
observe and try to rationalise some e†ects on the thermal
behaviour of the resulting silver complexes. Furthermore, two
di†erent silver salts were used: silver(I) dodecyl sulfate
(AgDOS) and silver(I) triÑuoromethanesulfonate (AgOTf).
the etheriÐcation of methyl 3,5-di- and 3,4,5-tri-hydroxy-
benzoates with 1-bromoalkane. The resulting methyl
poly(alkoxy)benzoates were then reduced to the correspond-
ing benzyl alcohol using lithium tetrahydroborate (LiBH )
4
in a 5 : 1 EtOHÈTHF mixture, and the alcohols were Ðnally
oxidised by pyridinium chlorochromate (PCC) in dich-
loromethane to furnish the desired poly(alkoxy)-
benzaldehydes.22 The poly(alkoxy)stilbazoles were synthe-
sised, as described previously, by condensation of the poly-
(alkoxy)benzaldehydes with 4-methylpyridine using lithium
diisopropylamide (LDA23) in THF, and followed by the de-
hydration of the intermediate alcohols by pyridinium toluene-
p-sulfonate salt (PPTS) in toluene at reÑux, the water formed
being continuously removed from the reaction mixture by the
use of a DeanÈStark apparatus. The complexes were subse-
quently prepared by stirring two equivalents of stilbazole with
one equivalent of the silver salt in dichloromethane (for
AgDOS), or in acetone (for AgOTf), at ambient temperature
and with the vessel protected from light.
The NMR spectroscopic data, 1H, 13C and 19F, were in
agreement with the proposed structures of the intermediates
and Ðnal substances, and the purity was conÐrmed by elemen-
tal analysis (C,H,N,S). All the stilbazoles were trans as evi-
denced by 1H NMR, in which the coupling constant of the AB
system was ca. 16È16.5 Hz. The complexes generate almost
identical spectra to the free ligands (for which the trans con-
Ðguration of the double bond was retained), although some
appreciable di†erences in chemical shifts (1H and 13C) indi-
cated that the complexation was achieved. 13C and 19F NMR
clearly showed that the triÑate complexes were formed, as in
the carbon spectra, a quartet was observed at d 121 corre-
sponding to the CÈF coupling, with a 1J \ 320 Hz, as well
CF
as a singlet (CF ) in the Ñuorine spectra at d ca. [80.
3
Thermal behaviour of the stilbazoles
The ligands will be abbreviated hereafter as St(n-x,y,z), where
n represents the number of carbon atoms in the Ñexible,
alkoxy chains, and x, y and z the position of the alkoxy chains
grafted on the terminal benzene ring [e.g. St(6-3,4) represents
3,4-dihexyloxystilbazole]. None of the stilbazoles was meso-
morphic.24 The loss of the liquid-crystalline properties was
nevertheless expected owing to the considerable reduction in
the molecular anisotropy resulting from the grafting of more
than one alkoxy chains in the 2- and/or 3-positions of the
terminal benzene ring. However, they were noticeable for their
low-melting temperatures (Table 6), some of them did even
not crystallise but remained as oils instead, a desired condi-
tion since when complexed to silver, the metal complexes
should equally show a substantial decrease in the transition
temperatures.
Thermal behaviour of the complexes
In general, the melting points of the complexes described here
were signiÐcantly lower than that of the “parentÏ complexes,
bis(4@-alkoxy-4-stilbazole)silver(I) dodecyl sulfate11b and tri-
Ñate,25 showing that the grafting of several alkoxy chains in
the periphery of the complex can be a productive approach to
obtain low-melting materials. A consequence of this important
depression in the melting temperatures of the mesomorphic
complexes is reÑected by the observation of larger meso-
morphic domains than in the corresponding parent systems,
since the clearing points remained almost unchanged. At Ðrst
glance, it seems that the type of mesophase was more depen-
dent on the substitution pattern of the ligand than the type of
anion (vide infra). However, appreciable di†erences between
the DOS series and the OTf series of polycatenar mesogens
were found for the melting points of the complexes, which
were higher in the triÑate series. This we largely attribute to a
greater degree of ionic character in the silverÈanion inter-
Results
Synthesis and characterisation of the ligands and their
complexes
The synthetic pathway used to prepare the ligands and the
silver complexes is shown in the scheme below. 2,4-Di-, 2,3,4-
tri- and 2,4,5-tri-alkoxybenzaldehydes were obtained directly
by etheriÐcation of the corresponding di- or tri-hydroxy-
benzaldehydes (Scheme 1, route 2) with the appropriate 1-
bromoalkane, under Williamsom ether conditions, in
butanone or pentan-2-one (the latter being found considerably
to ameliorate the yield of the O-alkylation reaction). However,
3,5-di- and 3,4,5-tri-alkoxybenzaldehydes were prepared di†er-
ently in three steps due to the high cost of the parent hydroxy-
benzaldehyde (Scheme 1, route 1). The Ðrst step consisted of
276
New J. Chem., 1999, 275È286

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Scheme 1 Synthesis of the stilbazoles and their complexes. i, C H
Br, K CO , butanone or pentan-2-one, reÑux, 24 h; ii, LiBH , THFÈ
n
2n`1
2
3
4
MeOH (5 : 1), N , reÑux, 12 h; iii, PCC, CH Cl , r.t., 4 h; iv, LDA, THF, [78 ¡C, N , 12 h; H OÈHCl, r.t., 2 h; PPTS, toluene, reÑux, 12 h; v,
2
2
2
2
2
AgX, CH Cl or acetone, r.t., 4 h.
2
2
action, thus requiring more energy to break down the lattice.
This is supported by the stronger tendency of the triÑate com-
plexes to crystallise on cooling, when compared to their
dodecyl sulfate analogues.11b,c,25 For all the mesomorphic
complexes described here, the mesophases were characterised
initially by optical microscopy, the nematic (N), smectic C
examples of mesomorphic tetracatenar mesogens having four
chains in the meta positions and only four aromatic rings.12
Thus, complexes with n \ 6È14 were mesomorphic showing
one type of mesophase from almost room temperature up to
90È120 ¡C (Fig. 2). The low-melting behaviour is likely con-
nected to the meta position of all the chains, and the absence
of chains in the para positions. On the basis of the optical
texture, the phase was assigned as columnar, and the presence
of large homeotropic areas further suggested the symmetry of
the mesophase to be hexagonal (uniaxial). Some of the com-
plexes were obtained as amorphous solids, and on cooling
from the isotropic liquid, they did not crystallise, although the
mesophase was not Ñuid below the temperature where the
compounds were expected to crystallise. In the following
heatÈcool cycles, no sign of crystal-to-columnar phase tran-
sition could be detected by DSC, and the optical texture of the
mesophase was preserved as seen in the optical microscope.
This peculiar thermal behaviour is consistent with the forma-
tion of anisotropic liquid-crystalline glasses (in the present
case columnar glasses),26 although we were not able to obtain
(S ), cubic (Cub) and columnar (Col) phases giving character-
C
istic textures1 and the transition temperatures detected by
DSC analysis.
Thermal behaviour of the silver(I) dodecyl sulfate complexes
The mesomorphism of the [AgSt(n-3,4) ][DOS] has already
2
be described,11a but will be recalled here in order to act as a
reference (Fig. 1). Thus, a bicontinuous Ia3d cubic phase (Cub)
was seen for 4 O n O 10 and a hexagonal columnar phase
(Col ) for 6 O n O 12. The domains of mesophase stability
h
were fairly large, especially those of the columnar phases, with
melting points in the range 55 to 70 ¡C, and clearing points
varying between 100 and 170 ¡C (Table 1).
Complexation of St(n-3,5) to silver(I) dodecyl sulfate also
T and *C from what turned out to be a poorly resolved
g
p
induced strongly mesomorphic materials, which are unique
DSC trace. The tetradecyloxy homologue presents two meso-
New J. Chem., 1999, 275È286
277

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Table 1 Transition temperatures and thermal data for [AgSt(n-3,5) ][DOS] and [AgSt(n-2,4) ][DOS]
2
2
Complex
n
Transition
T /¡C
*H/kJ mol~1
*S /J mol~1 K~1
m
[AgSt(n-3,5) ][DOS]
1
4
CrysÈI
160
98
119
32
95
34
93
29
113
32
107
41
76
123
61
71
(65)
57
È
È
2
CrysÈCrys@
8.4
22.6
99.0
15.6
4.0
CrysÈI
39.2
4.8
6
7
9
CrysÈCol
h
Col ÈI
1.5
h
gaÈCol
È
È
h
Col ÈI
0.3
0.8
5.0
h
gaÈCol
È
È
h
Col ÈI
1.9
h
12
14
CrysÈCol
14.3
1.8
94.9
14.8
1.9
28.1
18.9
È
90.3
([0.8)
([2.5)
46.9
4.8
302.6
42.5
4.8
83.9
54.9
h
Col ÈI
h
CrysÈCol
h1
Col ÈCol
h1
h2
Col ÈI
h2
[AgSt(n-2,4) ][DOS]
7
CrysÈCrys@
2
Crys@ÈI
(IÈN)
14
CrysÈI
(IÈN)
273.4
([2.6)
([7.6)
(53)
(50)
(NÈS )
C
a g stands for frozen mesophase or anisotropic glass.
phases (a reversible transition was clearly observed by DSC),
although no textural change was observed at the transition.
XRD studies corroborated the optical observations in the
sense that no structural change was detected. This may
suggest a transition between two hexagonal columnar phases
(the Ðrst order DSC transition is consistent with a transition
between two phases of the same symmetry), with a di†erent
type of order (or disorder) in the molecular organisation
within the columns, these columns being nevertheless associ-
ated according to a 2-D hexagonal array.
texture just before the transition). In both cases, crystallisation
occured on reaching room temperature.
Amongst the hexa-substituted substances, only the [AgSt(n-
3,4,5) ][DOS] complexes showed mesomorphic properties
2
(Table 2). All the complexes from n \ 4 to 14 showed the
expected columnar mesophase (Fig. 3), over an extended tem-
perature range (*T \ 100È120 ¡C). Most of them did not crys-
tallise on cooling, retaining the texture of the mesophase,
suggesting once more, the formation of anisotropic hexagonal
columnar glasses, although the glass transition could not be
observed by DSC.
In the second set of complexes, namely [AgSt(n-2,4) ]-
2
[DOS], only monotropic mesophases were observed (Table 1);
The complexes of the other two series of compounds,
[AgSt(n-2,3,4) ][DOS] and [AgSt(n-2,4,5) ][DOS], melted
for n \ 7 this was a nematic phase, while for n \ 14, both a
nematic and a smectic C phase were observed. Both phases
were recognised by their characteristic optical texture, and the
2
2
directly to the isotropic liquid without showing any meso-
phase on heating, nor any metastable phase on cooling. These
complexes showed strong supercooling e†ects, but they even-
tually crystallised after a few hours.
N-to-S transition was readily detected both by DSC and
C
optical microscopy (e.g. the formation of transition bars in the
Fig. 1 Phase diagram for the complexes [AgSt(n-3,4) ][DOS].
Fig. 2 Phase diagram for the complexes [AgSt(n-3,5) ][DOS].
2
2
278
New J. Chem., 1999, 275È286

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Table 2 Transition temperatures and thermal data for [AgSt(n-3,4,5) ]-
Table 3 Transition temperatures and thermal data for [AgSt(n-3,4) ]-
2
2
[DOS]
[OTf]
n
Transition
T /¡C
*H/kJ mol~1
*S /J mol~1 K~1
n
Transition
T /¡C
*H/kJ mol~1
*S /J mol~1 K~1
m
m
1
4
CrysÈI
180
42
53
127
38
133
34
125
34
141
30
141
28
141
32
È
È
4
6
7
CrysÈCrys@
Crys@ÈI
138
188
144
148
132
138
153
72
76
91
125
154
63
88
99
161
97
164
96
152
166
84
100
149
172
81
12.8
37.6
16.2
È
18.7
3.9
3.3
1.9
2.6
10.0
4.3
31.3
81.7
38.8
È
46.2
9.5
7.8
5.6
7.4
27.4
10.7
7.2
31.8
152.6
13.0
8.2
227.1
8.6
242.9
3.8
CrysÈCrys@
2.3
9.9
1.2
8.5
2.1
7.0
2.3
È
3.0
È
3.4
È
3.2
È
3.4
È
3.9
87.6
4.5
7.3
30.3
2.9
27.3
5.1
22.8
5.8
È
7.2
È
8.1
È
7.9
È
8.3
È
9.5
278.9
11.4
Crys@ÈCol
CrysÈCrys@
Crys@ÈI
h
Col ÈI
h
5
6
7
8
9
CrysÈCol
CrysÈCrys@
Crys@ÈCub
CubÈI
CrysÈCrys@
Crys@ÈCrysA
CrysAÈCrysÓ
CrysAÈCub
CubÈI
CrysÈCrys@
Crys@ÈCrysA
CrysAÈCub
CubÈI
h
Col ÈI
h
CrysÈCol
h
Col ÈI
8
h
gaÈCol
h
Col ÈI
h
gaÈCol
h
Col ÈI
3.1
h
gaÈCol
10
10.7
55.2
4.8
3.6
84.0
3.7
h
Col ÈI
h
10
11
14
gaÈCol
h
Col ÈI
137
37
133
41
h
gaÈCol
12
13
CrysÈCub
CubÈI
h
Col ÈI
h
CrysÈCol
CrysÈCub
89.7
1.6
h
Col ÈI
122
CubÈCol
h
h
Col ÈI
h
È
1.5
È
4.2
a g stands for frozen mesophase or anisotropic glass.
14
18
CrysÈCrys@
Crys@ÈCub
101.1
2.3
1.3
21.1
125.6
1.3
271.0
5.6
2.8
59.6
335.6
3.0
CubÈCol
h
Col ÈI
h
Thermal behaviour of the silver(I) triÑate complexes
CrysÈCrys@
Crys@ÈCol
101
151
The Ðrst series of triÑate complexes, [AgSt(n-3,4) ][OTf], dis-
played a very rich mesomorphism (Table 3), in a way very
h
2
Col ÈI
h
similar to the corresponding dodecyl sulfate complexes,11a
including both cubic and columnar mesophases (Fig. 4). The
cubic phase was seen for almost all homologues (7 O n O 14),
while the columnar phase appeared only for n P 13. XRD
studies conÐrmed these observations; the space group of the
cubic phase was assigned as Ia3d, and the columnar phase has
a 2-D hexagonal lattice. The temperature range of the cubic
phase was found to increase until n \ 12 (mainly on account
of a rather pronounced reduction in melting point with
increasing chain length) before it started to decrease, com-
pletely vanishing at the expense of the columnar phase at
n \ 14. For the compounds showing only the cubic phase, the
transition to the isotropic liquid was easily seen as the dis-
torted, imprisoned air-bubbles relaxed to a spherical shape, as
already seen in some lyotropic systems.27 The columnar phase
also exists over a wide temperature range, as it does in the
corresponding dodecyl sulfate series.
In the second series of complexes, [AgSt(n-3,5) ][OTf]
2
(Table 4), only the tetradecyloxy derivative was found to be
mesomorphic, the optical texture suggesting a hexagonal
columnar phase. The phase exists over a wide temperature
range (*T \ 70 ¡C), with a melting point slightly above
ambient (42 ¡C). On cooling, no crystallisation peak was seen
by DSC, but it did appear in the following heat (cold
crystallisation), followed by melting of the complex at 42 ¡C.
In the next series, [AgSt(n-2,4) ][OTf] (Table 4), the two
2
complexes synthesised (n \ 7 and 14) exhibited a monotropic
(metastable) nematic phase, in common with the analogous
dodecyl sulfate salts, though the smectic C found in the latter
Fig. 3 Phase diagram for the complexes [AgSt(n-3,4,5) ][DOS].
Fig. 4 Phase diagram for the complexes [AgSt(n-3,4) ][OTf].
2
2
New J. Chem., 1999, 275È286
279

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Table 4 Transition temperatures and thermal data for [AgSt(n-3,5) ][OTf] and [AgSt(n-2,4) ][OTf]
2
2
Complex
n
Transition
T /¡C
*H/kJ mol~1
*S /J mol~1 K~1
m
[AgSt(n-3,5) ][OTf]
6
9
CrysÈI
124
45
81
35
59
42
112
92
113
(88)
50
18.7
8.0
6.5
8.2
3.4
92.9
2.7
41.2
44.8
([1.2)
10.8
94.5
([0.9)
47.1
25.1
18.3
26.4
10.4
294.8
6.9
112.8
115.9
([3.3)
33.4
2
CrysÈCrys@
Crys@ÈI
12
14
7
CrysÈCrys@
Crys@ÈI
CrysÈCol
h
Col ÈI
h
[AgSt(n-2,4) ][OTf]
CrysÈCrys@
2
Crys@ÈI
(IÈN)
14
CrysÈCrys@
Crys@ÈI
(IÈN)
81
(78)
267.1
([2.7)
was absent here. The two compounds recrystallised a few
degrees below the isotropicÈnematic phase transition and
showed this behaviour reproducibly in the following heatÈ
cool cycles.
On heating, a Ðrst transition at 53 ¡C gave rise to a biphasic
region, comprising a cubic phase and a crystalline phase,
Crys@. The preparation was maintained at 60È62 ¡C for two
hours to see whether this phenomenom was due to the slow
kinetics of the crystal-to-cubic phase transition, thus, explain-
ing the delay in the melt of the crystal phase, or whether Crys@
was another thermodynamically stable crystalline structure.
No change was observed, suggesting that the initial bulk com-
pound contained two di†erent crystalline phases. On further
increasing the temperature, the crystalline phase, Crys@, melted
Of the hexacatenar complexes, [AgSt(n-2,3,4) ][OTf] and
2
[AgSt(n-2,4,5) ][OTf] melted to the isotropic liquid at 100È
2
120 ¡C for the octyloxy derivatives, and at 70È80 ¡C for the
tetradecyloxy derivatives, with no metastable phase being
detected on cooling from the isotropic liquid.
However, the complexes [AgSt(n-3,4,5) ][OTf] (Table 5)
2
exhibited a rather complicated thermal behaviour, and optical
to give a columnar mesophase, Col , at 65 ¡C, the phase being
h
microscopy suggested the following sequence (Fig. 5). The
butyloxy derivative melted at high temperature to the iso-
tropic liquid without showing any mesophase. The hexyloxy
and heptyloxy derivatives displayed a cubic phase, over a
narrow temperature range, the phase being assigned by the
growth of black, distorted domains until the whole area
became completely optically extinct. The phase this produced
was also rather viscous. The transitions were conÐrmed by
DSC, showing a broad peak at the crystal-to-cubic phase
transition, and another Ðrst order peak for the clearing point.
The octyloxy homologue showed a rather unusual meso-
morphism. Indeed, the optical observations, in addition to the
DSC traces, suggested that the silver complex crystallised as
two di†erent, thermodynamically stable polymorphic crystals.
recognisable by its optical texture. In this temperature range,
two mesophases were thus co-existing, a cubic and a columnar
phase. Here again, the preparation was left for two hours at
95 ¡C, but no change was observed. At 100 ¡C, the cubic phase
melted to a columnar phase, Col@ . Surprisingly, the two
h
columnar phases were not miscible as evidenced by large
boundaries between the two textures, although they displayed
identical defects. The mesophases did not mix when pressure
was applied on the cover-slip, nor when the temperature was
kept at 105 ¡C for two hours. Anyway, the non-miscibility of
the two columnar mesophases does not necessarily contradict
their possible identical nature. At 108 ¡C, the columnar phase
Col melted to the isotropic liquid, and the other Col even-
h
h{
tually melted at 127 ¡C. On cooling, the same mesophases and
biphasic regions were again observed, and this behaviour was
reproducible on subsequent heatÈcool cycles. The presence of
a cubic phase in this series was rather unexpected, and there is
Table 5 Transition temperatures and thermal data for
[AgSt(n-3,4,5) ][OTf]
2
T
*H
*S
m
n
Transition
/¡C /kJ mol~1 /J mol~1 K~1
4
6
CrysÈI
CrysÈCub
CubÈI
CrysÈCub
CubÈI
205
99 10.8
113
107
121
53
È
È
29.0
2.4
18.8
9.6
23.3
9.1
0.9
7.1
3.8
7.6
3.1
2.3
2.5
0.6
2.6
1.5
6.3
3.1
1.8
7
8a CrysÈCub ] Crys@
Cub ] Crys@ÈCub ] Col
65
h
Cub ] Col ÈCol ] Col
100
108
127
82
162
40
73
174
38 80.8
174
6.1
h
h{
h
Col ] Col ÈI ] Col
6.5
1.5
7.4
3.4
h{
h
h
I ] Col ÈI
h
CrysÈCol
h
9
Col ÈI
h
10
CrysÈCrys@
20.1
8.9
Crys@ÈCol
h
Col ÈI
4.1
h
11
12
14
CrysÈCol
259.8
4.0
230.3
5.0
126.4
246.4
5.5
h
Col ÈI
1.8
h
CrysÈCol
37 71.4
h
Col ÈI
h
170
2.2
50 40.9
62 82.6
CrysÈCrys@
Crys@ÈCol
h
Col ÈI
165
2.4
h
a Crys and Crys@: two crystalline phases of di†erent thermodynamic
stability; Col and Col : two immiscible hexagonal columnar phases
h
h{
with di†erent degree of ordering.
Fig. 5 Phase diagram for the complexes [AgSt(n-3,4,5) ][OTf].
2
280
New J. Chem., 1999, 275È286

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still no rational explanation so far for its occurence in the
phase diagram.
epitaxial relationships between the two mesophases, it was
concluded that the transition Col-to-Cub occured with rather
small structural changes, and a model based on undulated
columns was proposed. In the case of the triÑate compounds,
However, the most remarkable feature of the meso-
morphism of this homologue is that the biphasic behaviour
described was observed on cooling from the isotropic liquid
and on subsequent reheating cycles. This means that the
species giving rise to the two sets of mesomorphism are
somehow di†erent, and that this di†erence is not “annealedÏ
out in the isotropic phase. What we know is that the “as-
preparedÏ and “as-crystallisedÏ complex gives an elemental
preliminary X-ray results suggest
a completely di†erent
mechanism, since an important jump in the variation of the
lattice parameters of the two phases was recorded. The results
of this study will be reported in due course.29
Interestingly, the cubic phase-to-isotropic liquid transition
shows by DSC a fairly broad di†use endotherm which may
suggest a clearing process involving several steps. This pecu-
liar phenomenom has been attributed by others to the break-
down of the molecular order of the cubic lattice.30 This may
further explain the supercooling observed on cooling of the
isotropic liquid.
analysis consistent with the formulation [AgSt(8-3,4,5) ]-
2
[OTf], and so the initial supposition is that the species can
exist in more than one form, and these forms are not simply
related as di†erent crystal polymorphs. One possibility is
that the complex could exist as a mixture of monomer and
dimer. Recall that in the single crystal X-ray structure of
[AgSt(1-4) ][C H OSO ], the complex was found to exist as
Four alkoxy chains in the positions 3 and 5. The di†erence in
thermal behaviour as a function of the counter anion is more
evident here, and clearly shows the crucial role of the dodecyl
sulfate chain in stabilising mesophases. While only the tetra-
decyloxy homologue of the OTf series is mesomorphic
showing a columnar phase, all members of the DOS series are
mesomorphic for n [ 4. As mentioned above, these complexes
are virtually unique examples of mesomorphic 3,5-disub-
stituted tetracatenar materials with only four rings in the struc-
ture.12a,b For the DOS salts, the minimum requirement for
mesomorphism (six methylene groups per chain) is probably
linked to the absence of the alkoxy chains in the 4-position,
that is a minimum volume of aliphatic chains is required to be
able to generate an aliphatic matrix of sufficient density and in
an appropriate position to stabilise the columns and to com-
pensate the void created by the absence of chains in the 4-
position.
2
8
17
3
a dimer with two silver complex cations being held together
by bridging sulfate groups from the octyl sulfate chains.28 It is
conceivable that the triÑate salts have a similar structure, and
that a monomeric form can also exist. Thus, it is possible that
the behaviour is explained by the presence of non-
interconverting monomer and dimer.
The higher homologues (n P 9) behaved as typical hexa-
catenar mesogens do, in that they all showed an enantiotropic
columnar phase, with large anisotropic domains, increasing
from n \ 9 to 11, and then decreasing for n P 12. Compounds
with n \ 9 to 12 did not recrystallise on cooling, and did not
show a melting behaviour on subsequent heating. Similarly to
the previous compounds showing anisotropic glasses, it was
not possible to measure the *C and the T of the glass tran-
p
g
sition.
This reinforces the important role of the DOS chain in the
promotion of mesomorphism in these systems. Thus, on cross-
ing the aromatic/paraffinic boundary, the DOS chain interacts
sterically with the meta chains causing them to adopt a spatial
disposition di†erent to that in the triÑate salts where no such
steric interactions take place, as well as contributing positively
to the interfacial curvature. Thus, we propose that in addition
to enhancing the alkyl chain density, the DOS chain modiÐes
the spatial distribution and allows the void of the 4-position
chain to be more readily addressed. A test of this idea will be
available when the X-ray data are considered as there should
be no appreciable interdigitation of columns if this model is
correct.
Discussion
Systems containing four Ñexible alkoxy chains
Four alkoxy chains in the positions 3 and 4. The complexes
having this substitution pattern behave typically as tetra-
catenar mesogens, showing cubic and columnar phases,
although N and S phases are not seen.12a,b Slight di†erences
in the mesomorphism of the triÑate and dodecyl sulfate salts
were observed and while both showed enantiotropic cubic and
columnar mesophases with a wide temperature range, the tri-
Ñate salts had slightly higher transition temperatures.
C
However, the most important contrast is that in the triÑate
salts, the cubic phase appeared to longer chain length (n \ 7
to 14) than in the related DOS salts (n \ 4 to 10). This is
explained by recalling that in the DOS salts, the alkyl sulfate
chain adds to the curvature at the paraffinic/aromatic inter-
face whereas in the triÑate systems, this is not the case. Thus,
for a given chain length on the stilbazole, the interfacial curva-
ture will always be greater in the DOS salts, resulting in the
onset of columar mesophases at shorter chain lengths. A
related factor is likely to be due to the fact that mesophase
formation is goverened by the interfacial curvature which, in
turn, depends on the relative volumes of the core and the
chains. In the triÑate salts, not only does the anion not con-
tribute to the aliphatic chain density, but in fact it can act to
the opposite e†ect, increasing the volume of the core relative
to the chains. Thus, phases with more strongly curved inter-
faces will require longer chain lengths.
That the triÑate complexes are likely to be more ionic is
supported by their higher melting points, but the fact that the
clearing points of the two salts series are essentially the same
points to the fact that the global breakdown in ionic inter-
actions is not responsible for clearing, not inconsistent with a
lattice melting model.28
By XRD and dilatometry,11a a linear variation of the lattice
parameters and of the speciÐc volume of both phases of the
DOS series as a function of n was observed, even during the
cross-over from one phase to the other. After deduction of the
Four alkoxy chains in the positions 2 and 4. The complexes
having this substitution pattern showed only monotropic
behaviour, consisting of nematic and, in one case only, smectic
C phases. It is likely that the destabilisation of the liquid-
crystalline properties results from the alkoxy chain in the 2-
position which, it is assumed, acts as an additional lateral
group. This behaviour is consistent with that shown by some
organic liquid crystals having one or two lateral chain(s),
although in the latter, the nematic phases showed a higher
thermodynamic stability than in the present situation.
Systems containing six Ñexible alkoxy chains
Six alkoxy chains in the positions 3, 4 and 5. Almost all the
complexes having this substitution pattern showed a colum-
nar phase typical for such systems, although it appeared at
smaller values of n in the DOS salts (n \ 4) than in the OTf
salts (n \ 8), indicating once more the positive e†ect of the
dodecyl sulfate chains on the chain density and interfacial cur-
vature. The melting points are also much lower in the former
(28È53 ¡C) than in the latter (40È60 ¡C), although the phase
exists over a much wider temperature in the triÑate series
because of higher clearing temperatures.
One particularly striking feature is the rather unsual
thermal behaviour of the short homologues of the triÑate salts
New J. Chem., 1999, 275È286
281

View Article Online
(n \ 6, 7, 8). Indeed, the cubic phase displayed by these homo-
logues was not at all expected primarily owing the strong cur-
vature at the interface generated by the three periphal alkoxy
chains. However, recall the argument above which related the
enhanced volume of the core of these complexes to the pres-
ence of the triÑate anion. This argument is also consistent
with the observation of cubic phases in these hexacatenar
materials as the increased core volume will reduce the inter-
facial curvature increasing the likelihood of a cubic phase
being seen.
microscopy using a Zeiss Labpol microscope equipped with a
Linkam TH600 hot-stage and PR600 temperature controller.
All of the mesophases were characterised by their optical tex-
tures, and then conÐrmed by XRD. The spectroscopic and
analytical data of all the intermediate substances (aldehydes,
esters and alcohols) were good and in agreement with the pro-
posed structures.
Preparation of the poly(alkoxy)benzaldehydes
2,4-Di-, 2,3,4-tri- and 2,4,5-tri-alkoxybenzaldehydes were syn-
thesised as described previously, although for the trisubsti-
tuted benzaldehydes, pentan-2-one was prefered due to its
higher boiling point, and the reaction was carried out under
an inert atmosphere (N ). Two equivalents of K CO were
Six alkoxy chains in the positions 2, 3, 4 and 2, 4, 5. In these
systems, liquid-crystal properties were not expected because of
the location of two chains in the positions 2 and 3/5. Lateral
interactions were not favoured, as evidenced by the low tran-
sition temperatures, and the non-efficient packing of the
chains, both reasons excluding mesomorphism.
2
2
3
systematically used per hydroxy group. They were obtained in
good yields, ranging from 66 to 89%, and of analytical purity
after puriÐcation by Ñash column chromatography (silica gel,
CH Cl ). IR(CsI/Nujol, cm~1): 2,4-didecyloxybenzaldehyde:
Conclusions
2
2
l
l
l
1680s, l
2715w; 2,3,4-trioctyloxybenzaldehyde:
2730w; 2,4,5-trioctyloxybenzaldehyde:
2730w.
(C/O)
(C/O)
(C/O)
(HhC/0)
(HhC/0)
New low-melting metallomesogens have been obtained by
simple reaction of a silver fragment with various poly-
substituted stilbazole ligands. Furthermore, the wide collec-
tion of substances herein prepared allowed us to be able to
predict the liquid-crystalline properties, and thus to propose
some structureÈproperty relationships. Interestingly, the com-
plexation of the non-mesomorphic ligands to some silver salts
induced mesomorphism in many ligand/metal combinations,
proving in this case, that the mesomorphism is not necessarily
the result of molecular anisotropy itself, but depends on the
molecular aggregation and on the shape of these aggregates.
This highlights a very interesting analogy to lyotropic liquid
crystals, and can allow speculation about a general descrip-
tion of liquid crystalline mesophases. It seems indeed clearer
that similar principles of phase descriptions used in lyotropic
systems can be used here.
1688s, l
1660s, l
(HhC/0)
3,5-Di and 3,4,5-tri-alkoxybenzaldehydes were obtained dif-
ferently, and the preparation of one example is given. Methyl
3,5-dihydroxybenzoate (3.5 g, 20.2 mmol), K CO (11.2 g, 81.0
2
3
mmol) and 1-bromooctane (8.7 g, 44.4 mmol) were placed in a
Ñask Ðlled with pentan-2-one (100 cm3), and the reaction
mixture was heated at reÑux for 24 h. When cooled to room
temperature, the mixture was Ðltered through a pad of Celite
and the solvent evaporated under reduced pressure. The
product was puriÐed by column chromatography (SiO ,
2
CH Cl Èhexane 4 : 1). The yield was 84% (6.7 g). All of the
2
2
esters were puriÐed similarly, and obtained in good yields
ranging from 75 to 94%. IR(CsI/Nujol, cm~1): l 1730s,
(C/O)
The reduction was carried out under an atmosphere of
l
1300m.
(ChOMe)
In order to probe this analogy to lyotropic systems, we will
study the e†ects of aliphatic apolar solvents on the meso-
morphism of these silver(I) complexes, as several other groups
have already done.31 Preliminary results from simple contact
preparations between some silver(I) compounds and dodecane
look very promising, conÐrming the amphiphilic character of
these complexes. In this case, they behave typically as the so-
called amphotropic systems.6a,19,32
nitrogen. Methyl 3,5-dioctyloxybenzoate (6 g, 15.3 mmol) was
dissolved in THF (50 cm3), and LiBH (0.83 g, 38.2 mmol) was
4
added by portions to the solution; the mixture was heated at
reÑux for 1 h. Then, dry methanol (10 cm3) was added drop-
wise to the reÑuxing mixture over a period of 1 h. The mixture
was left 6 h at reÑux and under vigorous stirring, and was
then allowed to cool to room temperature. A solution of
dilute HCl (20 cm3, 3% v/v) was added until the pH was
neutral. The alcohol was extracted in diethyl ether (2 ] 250
cm3), washed with water (2 ] 200 cm3), rinsed with brine (100
Experimental procedures
All the solvents were distilled prior to use according to stan-
cm3), and the organic layer was dried over MgSO . The sol-
4
vents were removed under reduced pressure and the alcohol
dard procedures:33 CH Cl was distilled over calcium
puriÐed
by
Ñash-column
chromatography
(SiO ,
2
2
hydride, methanol from magnesium and iodine, tetra-
hydrofuran (THF) from sodium and benzophenone, toluene
from sodium, acetone from potassium permanganate. Diethyl
ether was dried and stored over sodium wire. 4-
Methylpyridine was distilled from sodium hydroxide and
stored over sodium hydroxide pellets. Potassium carbonate
was kept in the oven. All other chemicals were used as sup-
plied.
2
CH Cl ÈMeOH 99:1 to 90:10). The yield was e†ectively
2
2
quantitative (97%, 5.4 g). All of the benzyl alcohols were puri-
Ðed similarly, and obtained in good yields ranging from 85 to
97%. IR(CsI/Nujol, cm~1) l
3340br, s.
(OhH)
The oxidation of the alcohols was carried out in the air and
at room temperature. 3,5-Dioctyloxybenzyl alcohol (4 g, 11.0
mmol) was dissolved in CH Cl (10 cm3), and added to a sus-
2
2
pension of pyridinium chlorochromate (3.6 g, 16.5 mmol) in
1H, 13C and 19F NMR spectra were recorded on a Bruker
ACL250 or AM400 spectrometer and referenced to external
tetramethylsilane. The coupling constants were measured by
the use of a program Window NMR (1D-Win NMR, Bruker,
CH Cl (40 cm3). The mixture immediately turned dark as the
2
2
solution of alcohol was added, and was left stirred for 4 h. The
product was directly recovered following Ðltration over a pad
of silica gel and after evaporation of the solvent to give the
aldehyde in good yield (85%, 3.4 g). When necessary, the alde-
hydes were once more puriÐed by Ñash-column chromatog-
raphy (SiO , CH Cl ). All of the benzaldehydes were puriÐed
MS Window). One-bond (1J ) and multiple-bond (2J
,
CH
CH
3J , and 4J ) CÈH correlation spectra were recorded to
CH
CH
allow a correct and full assignment of the proton and carbon
peaks of all the substances. Microanalysis was performed by
the University of Sheffield micro-analytical service. Infrared
spectra were recorded on a PerkinÈElmer 684 spectrophoto-
meter. The study of the thermal behaviour was achieved by
DSC analysis, carried out using a PerkinÈElmer DSC7 instru-
ment using various heating rates (2, 5 and 10 K min~1) and
the mesomorphism was studied by hot-stage, polarising
2
2 2
similarly, and obtained in good yields ranging from 70 to
95%. IR(CsI/Nujol, cm~1): l 1705s, l 2710w.
(C/O) (HhC/0)
Preparation of the poly(alkoxy)stilbazoles
The Ðve new series of ligands were prepared and puriÐed in
the identical manner as the already given detailed procedure
282
New J. Chem., 1999, 275È286

View Article Online
for the preparation of 3,4-dialkoxy-4-stilbazole.11a All the
ligands were found to be analytically pure (Table 6), except for
some homologues of the 3,5-disubstituted series which were
found difficult to purify, and were used as such. Nevertheless,
the structure of all the ligands were conÐrmed by NMR spec-
troscopy, for which no extra signals or impurities were
observed. The NMR data of one derivative of each series are
given below, and the CÈH correlation spectra were made
available to the referees. The lettering of the hydrogen and
carbon atoms follows the same system as already used.12c The
protons of the double bond (k, l) and those of the pyridine
ring (n, o) were studied as a AB system and as a AA@XX@
system respectively.
St(8-3,4,5). d (250.13 MHz, CDCl ): 0.96 (a, t, 3J 6.5 Hz,
H
3
HH
3 H), 0.98 (a@, t, 3J 6.5 Hz, 6 H), 1.37 (b, b@, m, 30 H), 1.74 (c,
HH
c@, m, 6 H), 3.98 (d, t, 3J 6.5 Hz, 2 H), 4.02 (d@, t, 3J 6.5 Hz,
HH
HH
4 H), 6.72 (g, s, 2 H), 6.86 (l, AB, transJ 16.2 Hz, 1 H), 7.19 (k,
lk
AB, transJ 16.2 Hz, 1 H), 7.32 (n, AA@XX@, o J ] J o 6.4 Hz,
kl
no
no{
2 H), 8.54 (o, AA@XX@, o J ] J o 6.4 Hz, 2 H). d (62.9 MHz,
on
on{
C
CDCl ): 14.0 (a@), 14.1 (a), 22.6, 22.7, 25.8, 29.4, 29.7, 30.3, 31.6,
3
31.8 (b, b@, c, c@), 68.9 (d@), 73.5 (d), 105.7 (g), 120.8 (n), 124.8 (l),
131.3 (e), 133.4 (k), 139.2 (h), 144.8 (m), 150.1 (o), 153.4 (f).
St(8-2,3,4). d (250.13 MHz, CDCl ): 0.88, 0.90 (a, a@, aA, 2 t,
H
3
3J 6.7 Hz, 9 H), 1.39 (b, b@, bA, m, 30 H), 1.80 (c, c@, cA, m, 6
HH
H), 3.97, 3.98, 4.04 (d, d@, dA, 3 t, 3J 6.7 Hz, 6 H), 6.67 (j, d,
HH
lk
3J 9.0 Hz, 1 H), 6.90 (l, AB, transJ 16.6 Hz, 1 H), 7.28 (i, d,
ji
3J 9.0 Hz, 1 H), 7.32 (n, AA@XX@, o J ] J o 6.4 Hz, 2 H),
ij
7.58 (k, AB, transJ 16.6 Hz, 1 H), 8.52 (o, AA@XX@, o J ] J
kl on on{
6.4 Hz, 2 H). d (62.9 MHz, CDCl ): 14.0, 14.1 (a, a@, aA), 22.6,
no
no{
Spectroscopic and analytical data for the ligands [St(n-x,y,z)]
St(6-3,5). d (250.13 MHz, CDCl ): 0.90 (a@, t, 3J 6.6 Hz, 6
o
C
3
22.7, 25.8, 26.0, 29.3, 30.3, 30.4, 31.6, 31.7 (b, b@, bA, c, c@, cA),
68.8, 73.7, 74.3 (d, d@, dA), 108.6 (j), 120.6 (n), 120.9 (i), 123.2 (h),
124.4 (l), 128.1 (k), 141.9 (f), 145.5 (m), 150.0 (o), 151.8 (g), 154.1
(e).
H
3
HH
H), 1.41 (b@, m, 12 H), 1.78 (c@, m, 4 H), 3.96 (d@, t, 3J 6.6 Hz,
HH
4 H), 6.43 (e, t, 4J 2.3 Hz, 1 H), 6.67 (g, d, 4J 2.3 Hz, 2 H),
eg
ge
6.97 (l, AB, transJ 16.2 Hz, 1 H), 7.27 (k, AB, transJ 16.2 Hz, 1
lk
H), 7.33 (n, AA@XX@, o J ] J o 6.4 Hz, 2 H), 8.56 (o, AA@XX@,
no no{
kl
St(8-2,4,5). d (250.13 MHz, CDCl ): 0.86, 0.88 (a, a@, aA, 2 t,
o J ] J o 6.7 Hz, 2 H). d (62.9 MHz, CDCl ): 14.0 (a@), 22.6,
H
3
on
on{
C
3
3J 6.7 Hz, 9 H), 1.38 (b, b@, bA, m, 30 H), 1.80 (c, c@, cA, m, 6
25.7, 29.2, 31.6 (b@, c@), 67.8 (d@), 101.9 (e), 105.6 (g), 120.9 (n),
HH
H), 3.97, 3.98, 4.00 (d, d@, dA, 3 t, 3J 6.7 Hz, 6 H), 6.49 (f, s, 1
126.3 (l), 133.3 (k), 137.9 (h), 144.5 (m), 150.1 (o), 160.6 (f).
HH
H), 6.87 (l, AB, transJ 16.5 Hz, 1 H), 7.12 (i, s, 1 H), 7.32 (n,
lk
AA@XX@, o J ] J o 6.1 Hz, 2 H), 7.61 (k, AB, transJ 16.5 Hz,
St(7-2,4). d (250.13 MHz, CDCl ): 0.89, 0.90 (a, aA, 2 t, 3J
no
no{
kl
H
3
HH
1 H), 8.52 (o, AA@XX@, o J ] J o 6.1 Hz, 2 H). d (62.9 MHz,
6.4 Hz, 6 H), 1.40 (b, bA, m, 16 H), 1.82 (c, cA, m, 4 H), 3.96,
3.99 (d, dA, 2 t, 3J 6.4 Hz, 4 H), 6.45 (f, d, 4J 2.0 Hz, 1 H),
on
on{
C
CDCl ): 14.1 (a, a@, aA), 22.7, 26.1, 26.3, 29.3, 29.4, 29.6, 31.8 (b,
3
HH
fj
b@, bA, c, c@, cA), 69.3, 69.7, 70.7 (d, d@, dA), 100.4 (f), 113.5 (i),
6.49 (j, dd, 3J 8.5 Hz, 4J 2.0 Hz, 1 H), 6.95 (l, AB, transJ 16.5
ji
Hz, 1 H), 7.31 (n, AA@XX@, o J ] J o 6.1 Hz, 2 H), 7.47 (i, d,
no no{
3J 8.5 Hz, 1 H), 7.58 (k, AB, transJ 16.5 Hz, 1 H), 8.51 (o,
ij kl
jg
lk
117.5 (h), 120.6 (n), 123.6 (l), 127.9 (k), 143.3 (j), 145.7 (m), 150.0
(o), 151.3 (e), 152.4 (g).
AA@XX@, o J ] J o 6.1 Hz, 2 H). d (62.9 MHz, CDCl ): 14.1
Preparation of the silver complexes
on
on{
C
3
(a, aA), 22.6, 26.0, 26.2, 29.1, 29.2, 29.3, 31.8 (b, bA, c, cA), 68.2,
68.5 (d, dA), 99.8 (f), 105.8 (j), 118.1 (h), 120.6 (n), 123.7 (l), 128.2
(i), 128.3 (k), 145.9 (m), 150.0 (o), 158.2 (g), 160.9 (e).
The preparation of the silver(I) dodecyl sulfate was achieved as
previously described.11a In the case of the silver(I) triÑate com-
Table 6 Microanalytical data for the stilbazolesa
St(n-x,y,z)
Yield (%)
MP/¡C
C
H
N
St(13-3,4)
St(14-3,4)
St(18-3,4)
St(1-3,5)
St(4-3,5)b
St(6-3,5)
St(7-3,5)
St(9-3,5)
St(11-3,5)
St(12-3,5)
St(14-3,5)
St(7-2,4)
St(10-2,4)
St(14-2,4)
St(1-3,4,5)
St(4-3,4,5)
St(5-3,4,5)b
St(6-3,4,5)b
St(7-3,4,5)
St(8-3,4,5)
St(9-3,4,5)
St(10-3,4,5)
St(11-3,4,5)
St(12-3,4,5)
St(14-3,4,5)
St(6-2,3,4)b
St(8-2,3,4)b
St(10-2,3,4)
St(12-2,3,4)
St(14-2,3,4)
St(8-2,4,5)
St(14-2,4,5)
89
70
78
58
89
80
75
62
53
86
85
40
77
82
58
67
85
90
85
86
78
82
76
66
90
74
90
76
61
89
84
86
89
91
94
92
È
36
49
55
51
55
64
64
44
55
97
64
È
È
49
48
41
44
48
51
57
È
È
41
51
63
66
65
80.7 (81.0)
80.5 (81.3)
81.2 (81.9)
74.5 (74.7)
75.4 (77.5)
78.1 (78.7)
78.5 (79.2)
79.5 (80.0)
79.6 (80.6)
79.8 (80.8)
80.6 (81.3)
78.9 (79.2)
80.0 (80.3)
81.3 (81.3)
70.4 (70.8)
75.7 (75.5)
76.5 (76.5)
76.6 (77.3)
77.9 (78.0)
78.6 (78.5)
78.9 (79.0)
79.6 (79.4)
79.8 (79.8)
79.9 (80.2)
80.5 (80.7)
76.8 (77.3)
78.3 (78.5)
79.6 (79.4)
79.9 (80.2)
80.8 (80.7)
78.5 (78.5)
80.3 (80.7)
11.1 (11.0)
11.3 (11.1)
12.0 (11.6)
6.4 (6.3)
8.1 (8.4)
9.2 (9.2)
2.3 (2.4)
2.7 (2.3)
1.8 (1.9)
5.8 (5.8)
3.9 (4.3)
4.0 (3.7)
3.7 (3.4)
2.8 (3.0)
2.4 (2.7)
2.7 (2.5)
2.5 (2.3)
3.3 (3.4)
3.0 (2.8)
2.3 (2.3)
5.1 (5.2)
3.5 (3.5)
3.2 (3.2)
2.7 (2.9)
2.6 (2.7)
2.5 (2.5)
2.0 (2.3)
2.1 (2.1)
2.1 (2.0)
1.7 (1.9)
1.6 (1.7)
2.9 (2.9)
2.4 (2.5)
2.4 (2.1)
1.8 (1.9)
1.4 (1.7)
2.6 (2.5)
1.4 (1.7)
9.8 (9.6)
10.3 (10.2)
11.0 (10.6)
10.9 (10.8)
11.2 (11.1)
9.8 (9.6)
10.4 (10.4)
11.4 (11.1)
6.2 (6.3)
9.0 (8.9)
9.5 (9.4)
9.8 (9.8)
10.1 (10.2)
10.7 (10.5)
11.1 (10.8)
11.1 (11.0)
11.3 (11.2)
11.3 (11.4)
11.8 (11.7)
9.4 (9.8)
10.8 (10.5)
11.0 (11.0)
11.4 (11.4)
11.8 (11.7)
10.6 (10.5)
12.0 (11.7)
a Calculated values in parentheses (%). b Obtained as oils.
New J. Chem., 1999, 275È286
283

View Article Online
plexes, the reactions were carried out in dry acetone. When
cooled, the resulting yellow precipitate was Ðltered, crys-
tallised from hot acetone (once or twice), recovered by Ðl-
tration and dried under high vacuum. The complexes were
obtained in satisfying yields, with good analytical purity
(Tables 7 and 8). The NMR data (1H, 13C and 19F) were in
agreement with the expected structures, and are given below
for one homolog of each series.
42 H), 1.67 (q, m, 2 H), 1.76 (c@, m, 8 H), 3.90 (d@, t, 3J 6.7 Hz,
HH
8 H), 4.13 (p, t, 3J 6.7 Hz, 2 H), 6.41 (e, t, 4J 2.1 Hz, 2 H),
HH
eg
6.57 (g, d, 4J 2.1 Hz, 4 H), 6.87 (l, AB, transJ 16.2 Hz, 2 H),
ge
7.17 (k, AB, transJ 16.2 Hz, 2 H), 7.39 (n, AA@XX@, o J ] J
kl no no{
lk
o
6.4 Hz, 4 H), 8.69 (o, AA@XX@, o J ] J o 6.4 Hz, 4 H). d (62.9
on
on{
C
MHz, CDCl ): 14.1 (a@, s), 22.7, 25.8, 26.1, 29.3, 29.5, 29.6, 29.7,
3
31.9 (b@, c@, r, q), 68.1 (p), 69.2 (d@), 102.6 (e), 105.7 (g), 121.7 (n),
124.6 (l), 135.8 (k), 137.1 (h), 146.9 (m), 151.8 (o), 160.5 (f).
Spectroscopic and analytical data for the complexes [AgSt(n-
[AgSt(7-2,4) ] [DOS]. d (250.13 MHz, CDCl ): 0.84 (s, t,
2
H
3
x,y,z) ] [DOS]
3J 6.7 Hz, 3 H), 0.89 (a, aA, t, 3J 6.7 Hz, 12 H), 1.35 (b, bA,
2
HH
HH
[AgSt(6-3,5) ] [DOS]. d (250.13 MHz, CDCl ): 0.84 (s, t,
r, m, 50 H), 1.67 (q, m, 2 H), 1.81 (c, cA, m, 8 H), 3.94 (d, dA, t,
3J 6.7 Hz, 8 H), 4.11 (p, t, 3J 6.7 Hz, 2 H), 6.39 (f, d, 4J
2
H
3
3J 6.7 Hz, 3 H), 0.91 (a@, t, 3J 6.7 Hz, 12 H), 1.34 (b@, r, m,
HH
HH
HH
HH
fj
Table 7 Microanalytical data for the AgDOS complexesa
Complex
n
Yield (%)
C
H
N
S
[AgSt(n-3,5) ][DOS]
1
4
6
7
9
12
14
7
14
1
4
5
6
7
8
9
10
11
14
8
14
8
74
28
58
38
69
51
67
67
74
76
56
15
32
68
64
51
58
55
64
53
79
52
45
58.5 (58.9)
63.1 (63.3)
66.1 (65.5)
66.7 (66.5)
68.1 (68.1)
70.2 (70.1)
71.5 (71.2)
65.8 (66.5)
71.1 (71.2)
57.6 (57.7)
63.5 (63.7)
65.6 (65.2)
66.6 (66.5)
67.4 (67.6)
68.8 (68.6)
69.4 (69.5)
70.5 (70.3)
71.3 (71.1)
72.7 (72.9)
68.6 (68.6)
73.4 (72.9)
68.6 (68.6)
72.8 (72.9)
6.5 (6.5)
7.8 (7.8)
8.6 (8.4)
8.5 (8.7)
9.4 (9.2)
9.8 (9.8)
10.2 (10.1)
8.8 (8.7)
10.2 (10.1)
6.5 (6.5)
8.2 (8.2)
8.9 (8.6)
9.0 (9.0)
9.3 (9.3)
9.7 (9.6)
10.0 (9.8)
10.2 (10.1)
9.5 (10.3)
10.8 (10.8)
9.5 (9.6)
10.9 (10.8)
9.7 (9.6)
3.2 (3.3)
2.8 (2.7)
2.4 (2.5)
2.4 (2.3)
2.2 (2.1)
1.9 (1.9)
1.6 (1.8)
2.2 (2.3)
1.7 (1.8)
3.0 (3.1)
2.3 (2.4)
2.4 (2.2)
2.1 (2.1)
2.2 (2.0)
1.8 (1.9)
1.9 (1.8)
1.6 (1.7)
2.0 (1.6)
1.7 (1.4)
1.8 (1.9)
1.4 (1.4)
1.8 (1.9)
1.6 (1.4)
2.7 (3.7)
3.2 (3.1)
2.8 (2.8)
2.8 (2.7)
2.6 (2.5)
2.4 (2.2)
2.2 (2.0)
2.8 (2.7)
2.0 (2.0)
3.5 (3.5)
2.6 (2.7)
2.6 (2.5)
2.7 (2.4)
2.4 (2.3)
2.1 (2.1)
2.1 (2.0)
2.0 (1.9)
1.8 (1.8)
1.5 (1.6)
2.1 (2.1)
1.4 (1.6)
2.2 (2.1)
1.6 (1.6)
2
[AgSt(n-2,4) ][DOS]
2
[AgSt(n-3,4,5) ][DOS]
2
[AgSt(n-2,3,4) ][DOS]
2
[AgSt(n-2,4,5) ][DOS]
2
14
10.9 (10.8)
a Calculated values in parentheses (%).
Table 8 Microanalytical data for the AgOTf complexesa
Complex
n
Yield (%)
C
H
N
S
[AgSt(n-3,4) ][OTf]
4
6
7
8
10
12
13
14
18
6
82
88
75
80
64
94
80
89
88
56
66
40
79
61
87
54
50
64
80
53
51
60
61
78
85
92
75
76
56.5 (59.6)
59.6 (60.0)
60.9 (61.4)
61.8 (62.6)
64.9 (64.7)
66.4 (66.4)
67.0 (67.2)
67.4 (67.9)
71.1 (70.2)
59.1 (60.0)
63.4 (63.7)
66.4 (66.4)
67.6 (67.9)
61.3 (61.4)
67.3 (67.9)
57.8 (58.2)
61.7 (62.0)
63.3 (63.5)
64.7 (64.9)
66.1 (66.0)
66.8 (67.1)
67.7 (68.1)
68.3 (68.9)
70.3 (70.4)
65.3 (64.9)
69.6 (70.4)
64.4 (64.9)
70.6 (70.4)
5.8 (6.0)
6.9 (6.9)
7.2 (7.3)
7.7 (7.7)
8.4 (8.3)
8.6 (8.8)
8.9 (9.0)
9.5 (9.2)
10.2 (9.9)
6.9 (6.9)
8.1 (8.0)
8.7 (8.8)
9.3 (9.2)
7.4 (7.3)
9.2 (9.2)
6.7 (6.7)
7.6 (7.8)
8.2 (8.2)
8.6 (8.6)
8.9 (8.9)
9.1 (9.2)
9.6 (9.5)
9.5 (9.7)
10.3 (10.1)
8.6 (8.6)
10.4 (10.1)
8.7 (8.6)
10.6 (10.1)
3.2 (3.1)
2.8 (2.7)
2.6 (2.6)
2.8 (2.5)
2.1 (2.2)
1.9 (2.1)
2.0 (2.0)
1.9 (1.9)
1.9 (1.6)
2.6 (2.7)
2.6 (2.3)
2.0 (2.1)
1.7 (1.9)
2.8 (2.6)
1.9 (1.9)
2.7 (2.7)
2.3 (2.3)
2.2 (2.1)
2.0 (2.0)
1.9 (1.9)
1.7 (1.8)
1.4 (1.7)
1.6 (1.6)
1.3 (1.5)
2.0 (2.0)
1.6 (1.5)
2.0 (2.0)
1.4 (1.5)
4.0 (3.5)
3.7 (3.1)
3.7 (3.0)
2.7 (2.8)
3.0 (2.6)
2.7 (2.4)
2.2 (2.3)
2.4 (2.2)
(1.9)
3.7 (3.1)
2.9 (2.7)
2.4 (2.4)
2.8 (2.2)
3.3 (3.0)
1.8 (2.2)
3.1 (3.0)
2.9 (2.6)
2.6 (2.5)
2.7 (2.3)
2.5 (2.2)
2.3 (2.1)
1.8 (1.9)
1.9 (1.9)
1.8 (1.7)
2.4 (2.3)
1.8 (1.7)
2.5 (2.3)
2.0 (1.7)
2
[AgSt(n-3,5) ][OTf]
2
9
12
14
7
14
4
6
7
[AgSt(n-2,4) ][OTf]
2
[AgSt(n-3,4,5) ][OTf]
2
8
9
10
11
12
14
8
14
8
[AgSt(n-2,3,4) ][OTf]
2
[AgSt(n-2,4,5) ][OTf]
2
14
a Calculated values in parentheses (%).
284
New J. Chem., 1999, 275È286

View Article Online
2.1 Hz, 2 H), 6.41 (j, dd, 3J 8.3 Hz, 4J 2.1 Hz, 2 H), 6.87 (l,
ji jg
AB, transJ 16.5 Hz, 2 H), 7.33 (n, AA@XX@, o J ] J o 6.4 Hz,
lk no no{
4 H), 7.38 (i, d, 3J 8.3 Hz, 2 H), 7.58 (k, AB, transJ 16.5 Hz, 2
ij kl
8.59 (o, AA@XX@, o J ] J o 6.4 Hz, 4 H). d (62.9 MHz,
on
on{
C
CDCl ): 14.1 (a@), 22.7, 26.1, 29.3, 29.5, 29.6, 31.9 (b@, c@), 68.1
3
(d@), 102.8 (e), 105.6 (g), 120.8 (CF , q, J 320 Hz), 121.9 (n),
3
CF
H), 8.64 (o, AA@XX@, o J ] J o 6.4 Hz, 4 H). d (62.9 MHz,
124.3 (l), 136.2 (k), 136.9 (h), 147.3 (m), 152.0 (o), 160.5 (f).
on
on{
C
CDCl ): 14.1 (a, aA, s), 22.6, 26.0, 26.1, 29.0, 29.1, 29.3, 29.5,
d (235.36 MHz, CDCl ): [78 (CF , s).
3
F
3
3
29.7, 31.8, 31.9 (b, bA, c, cA, r, q), 68.0 (p) 68.1, 68.4 (d, dA), 99.5
(f), 105.7 (j), 117.5 (h), 121.3 (n), 122.3 (l), 128.6 (i), 130.6 (k),
148.1 (m), 152.1 (o), 158.5 (g), 161.4 (e).
[AgSt(7-2,4) ] [OTf]. d (250.13 MHz, CDCl ): 0.90 (a, aA,
2
H
3
t, 3J 6.7 Hz, 12 H), 1.40 (b, bA, m, 32 H), 1.81 (c, cA, m, 8 H),
HH
3.95, 3.96 (d, dA, 2 t, 3J 6.7 Hz, 8 H), 6.39 (f, d, 4J 2.1 Hz, 2
HH
fj
[AgSt(8-3,4,5) ] [DOS]. d (250.13 MHz, CDCl ): 0.84 (s, t,
H), 6.41 (j, dd, 3J 8.3 Hz, 4J 2.1 Hz, 2 H), 6.88 (l, AB, transJ
2
H
3
ji
16.5 Hz, 2 H), 7.35 (n, AA@XX@, o J ] J o 6.7 Hz, 4 H), 7.37
no no{
(i, d, 3J 8.3 Hz, 2 H), 7.60 (k, AB, transJ 16.5 Hz, 2 H), 8.56 (o,
ij kl
jg
lk
3J 6.7 Hz, 3 H), 0.85 (a, t, 3J 6.4 Hz, 6 H), 0.88 (a@, t, 3J
HH
HH
HH
6.4 Hz, 12 H), 1.35 (b, b@, r, m, 78 H), 1.67 (q, m, 2 H), 1.78 (c,
c@, m, 12 H), 3.97 (d, t, 3J 6.4 Hz, 4 H), 3.98 (d@, t, 3J 6.4
AA@XX@, o J ] J o 6.4 Hz, 4 H). d (62.9 MHz, CDCl ): 14.1
HH
HH
on
on{
C
3
Hz, 8 H), 4.09 (p, t, 3J 6.7 Hz, 2 H), 6.70 (g, s, 4 H), 6.81 (l,
(a, aA), 22.6, 26.0, 26.1, 29.1, 29.3, 31.8, 31.9 (b, bA, c, cA), 68.2,
68.5 (d, dA), 99.6 (f), 105.8 (j), 117.4 (h), 120.8 (CF , q, J 320
HH
AB, transJ 16.2 Hz, 2 H), 7.22 (k, AB, transJ 16.2 Hz, 2 H),
lk
kl
3
CF
7.42 (n, AA@XX@, o J ] J o 6.4 Hz, 4 H), 8.67 (o, AA@XX@,
Hz), 121.5 (n), 122.0 (l), 128.9 (i), 131.4 (k), 148.9 (m), 151.0 (o),
no no{
o J ] J o 6.4 Hz, 4 H). d (62.9 MHz, CDCl ): 14.1 (a, a@, s),
158.7 (g), 161.6 (e). d (235.36 MHz, CDCl ): [78 (CF , s).
on
on{
C
3
F
3
3
22.6, 22.7, 25.8, 26.1, 29.1, 29.3, 29.4, 30.4, 31.8, 31.9 (b, b@, c, c@,
r, q), 68.1 (p), 69.2 (d@), 73.6 (d), 106.0 (g), 121.7 (n), 123.4 (l),
130.6 (e), 135.9 (k), 139.8 (h), 147.2 (m), 151.8 (o), 153.4 (f).
[AgSt(7-3,4,5) ] [OTf]. d (250.13 MHz, CDCl ): 0.88 (a, t,
2
H
3
3J 6.7 Hz, 6 H), 0.89 (a@, t, 3J 6.7 Hz, 12 H), 1.39 (b, b@, m,
HH
HH
48 H), 1.78 (c, c@, m, 12 H), 3.95 (d@, t, 3J 6.7 Hz, 8 H), 3.97
HH
[AgSt(8-2,3,4) ] [DOS]. d (250.13 MHz, CDCl ): 0.85 (s, t,
(d, t, 3J 6.7 Hz, 4 H), 6.67 (g, s, 4 H), 6.79 (l, AB, transJ 16.2
2
H
3
HH
lk
3J 6.7 Hz, 3 H), 0.86, 0.87 (a, a@, aA, 2 t, 3J 6.7 Hz, 18 H),
Hz, 2 H), 7.21 (k, AB, transJ 16.2 Hz, 2 H), 7.40 (n, AA@XX@,
HH
HH
kl
1.35 (b, b@, bA, r, m, 78 H), 1.66 (q, m, 2 H), 1.80 (c, c@, cA, m, 12
o J ] J o 6.4 Hz, 4 H), 8.58 (o, AA@XX@, o J ] J o 6.4 Hz,
no
no{
on
on{
H), 3.96, 3.97, 4.03 (d, d@, dA, 3 t, 3J 6.7 Hz, 12 H), 4.10 (p, t,
4 H). d (62.9 MHz, CDCl ): 14.1 (a, a@), 22.6, 26.1, 29.1, 29.3,
HH
C
3
3J 6.7 Hz, 2 H), 6.62 (j, d, 3J 8.7 Hz, 2 H), 6.86 (l, AB,
29.4, 30.4, 31.9 (b, b@, c, c@), 69.2 (d@), 73.6 (d), 105.9 (g), 120.8
HH
ji
transJ 16.5 Hz, 2 H), 7.22 (i, d, 3J 8.7 Hz, 2 H), 7.39 (n,
(CF , q, J 320 Hz), 121.8 (n), 123.0 (l), 130.4 (e), 136.3 (k),
lk
AA@XX@, o J ] J o 6.4 Hz, 4 H), 7.61 (k, AB, transJ 16.5 Hz,
no no{ kl
ij
3
CF
139.9 (h), 147.5 (m), 152.0 (o), 153.4 (f). d (235.36 MHz,
CDCl ): [78 (CF , s).
F
2 H), 8.67 (o, AA@XX@, o J ] J o 6.4 Hz, 4 H). d (62.9 MHz,
on
on{
C
3
3
CDCl ): 14.1 (a, a@, aA, s), 22.6, 26.0, 26.1, 26.2, 29.3, 29.4, 29.6,
3
29.7, 30.3, 31.8, 31.9 (b, b@, bA, c, c@, cA, r, q), 68.0 (p), 68.7, 73.7,
[AgSt(8-2,3,4) ] [OTf]. d (250.13 MHz, CDCl ): 0.85, 0.89
2
H
3
74.4 (d, d@, dA), 108.4 (j), 121.3 (i), 121.5 (n), 122.6 (h), 123.0 (l),
130.5 (k), 141.8 (f), 147.8 (m), 152.0 (o), 152.1 (g), 154.6 (e).
Thermal data [T /¡C (*H/kJ mol~1)]: n \ 8, Crys Æ 98 (23) Æ I;
n \ 14, Crys Æ 41 (77) Æ Crys@ Æ52 (37) Æ I.
(a, a@, aA, 2 t, 3J 6.7 Hz, 18 H), 1.39 (b, b@, bA, m, 60 H), 1.78
HH
(c, c@, cA, m, 12 H), 3.95, 3.96, 4.02 (d, d@, dA, 3 t, 3J 6.7 Hz, 12
HH
H), 6.56 (j, d, 3J 8.8 Hz, 2 H), 6.81 (l, AB, transJ 16.5 Hz, 2 H),
ji
lk
7.15 (i, d, 3J 8.8 Hz, 2 H), 7.33 (n, AA@XX@, o J ] J o 6.7
ij
no
no{
Hz, 4 H), 7.59 (k, AB, transJ 16.5 Hz, 2 H), 8.59 (o, AA@XX@,
kl
[AgSt(8-2,4,5) ] [DOS]. d (250.13 MHz, CDCl ): 0.84 (s, t,
o J ] J o 6.7 Hz, 4 H). d (62.9 MHz, CDCl ): 14.1 (a, a@, aA),
2
H
3
on
on{
C
3
3J 6.7 Hz, 3 H), 0.87, 0.88 (a, a@, aA, 2 t, 3J 6.7 Hz, 18 H),
22.7, 26.2, 29.3, 29.4, 29.5, 29.6, 30.4, 31.8, 31.9 (b, b@, bA, c, c@,
cA), 68.7, 73.7, 74.4 (d, d@, dA), 108.4 (j), 120.8 (CF , q, J 320
HH
HH
1.35 (b, b@, bA, r, m, 78 H), 1.66 (q, m, 2 H), 1.82 (c, c@, cA, m, 12
3
CF
H), 3.93, 3.94, 3.99 (d, d@, dA, 3 t, 3J 6.7 Hz, 12 H), 4.10 (p, t,
Hz), 121.3 (i), 121.5 (n), 122.5 (h), 122.9 (l), 130.7 (k), 141.8 (f),
HH
3J 6.7 Hz, 2 H), 6.43 (f, s, 2 H), 6.83 (l, AB, transJ 16.5 Hz, 2
147.9 (m), 152.0 (o), 152.1 (g), 154.6 (e). d (235.36 MHz,
HH
lk
F
H), 7.06 (i, s, 2 H), 7.39 (n, AA@XX@, o J ] J o 6.6 Hz, 4 H),
CDCl ): [78 (CF , s). Thermal data [T /¡C (*H/kJ mol~1)]:
no
7.64 (k, AB, transJ 16.5 Hz, 2 H), 8.64 (o, AA@XX@, o J ] J
kl on on{
6.6 Hz, 4 H). d (62.9 MHz, CDCl ): 14.1 (a, a@, aA, s), 22.7, 26.0,
no{
3
3
o
n \ 8, Crys Æ 119 (24) Æ I; n \ 14, Crys Æ 65 (44) Æ Crys@ Æ72
(27) Æ I.
C
3
26.1, 26.2, 29.3, 29.4, 29.6, 29.7, 31.8 (b, b@, bA, c, c@, cA, r, q), 68.0
(p), 69.2, 69.5, 70.6 (d, d@, dA), 99.8 (f), 113.5 (i), 116.6 (h), 121.5
(n), 122.0 (l), 130.5 (k), 143.2 (j), 148.2 (m), 151.8 (o), 151.9 (e),
152.9 (g). Thermal data [T /¡C (*H/kJ mol~1)]: n \ 8,
Crys Æ 88 (78) Æ I; n \ 14, Crys Æ 64 (55) Æ Crys@ Æ78 (89) Æ I.
[AgSt(8-2,4,5) ] [OTf]. d (250.13 MHz, CDCl ): 0.88, 0.89
2
H
3
(a, a@, aA, t, 3J 6.7 Hz, 18 H), 1.39 (b, b@, bA, m, 60 H), 1.81 (c,
HH
c@, cA, m, 12 H), 3.92, 3.93, 3.99 (d, d@, dA, 3 t, 3J 6.7 Hz, 12
HH
H), 6.42 (f, s, 2 H), 6.83 (l, AB, transJ 16.5 Hz, 2 H), 7.04 (i, s, 2
lk
H), 7.39 (n, AA@XX@, o J ] J o 6.4 Hz, 4 H), 7.64 (k, AB,
no
no{
transJ 16.5 Hz, 2 H), 8.57 (o, AA@XX@, o J ] J o 6.4 Hz, 4 H).
Spectroscopic and analytical data for the complexes [AgSt(n-
kl
on
on{
d (62.9 MHz, CDCl ): 14.1 (a, a@, aA), 22.7, 26.1, 26.2, 29.3,
x,y,z) ] [OTf]
C
3
2
29.4, 29.6, 31.8 (b, b@, bA, c, c@, cA), 69.2, 69.4, 70.6 (d, d@, dA), 99.7
[AgSt(7-3,4) ] [OTf]. d (250.13 MHz, CDCl ): 0.90 (a, a@, t,
(f), 113.5 (i), 116.4 (h), 120.8 (CF , q, J 320 Hz), 121.5 (n),
2
H
3
3
CF
3J 6.7 Hz, 12 H), 1.40 (b, b@, m, 32 H), 1.81 (c, c@, m, 8 H),
121.6 (l), 130.8 (k), 143.2 (j), 148.6 (m), 151.9 (o), 152.0 (e), 152.9
HH
3.94, 3.98 (d, d@, 2 t, 3J 6.7 Hz, 8 H), 6.69 (l, AB, transJ 16.5
(g). d (235.36 MHz, CDCl ): [78 (CF , s). Thermal data
HH
lk
F
3
3
Hz, 2 H), 6.71 (j, d, 3J 8.5 Hz, 2 H), 6.88 (i, dd, 3J 8.5 Hz,
[T /¡C (*H/kJ mol~1)]: n \ 8, Crys Æ 58 (10) Æ Crys@ Æ110
(60) Æ I; n \ 14, Crys Æ 67 (41) Æ Crys@ Æ80 (40) Æ I.
ji
4J 1.8 Hz, 2 H), 6.96 (g, d, 4J 1.8 Hz, 2 H), 7.18 (k, AB,
ig ig
transJ 16.5 Hz, 2 H), 7.29 (n, AA@XX@, o J ] J o 6.4 Hz, 4 H),
kl no no{
ji
8.56 (o, AA@XX@, o J ] J o 6.4 Hz, 4 H). d (62.9 MHz,
on
on{
C
CDCl ): 14.1 (a, a@), 22.7, 26.0, 29.2, 29.3, 31.9 (b, b@, c, c@), 69.0,
3
References
69.2 (d, d@), 111.5 (g), 113.0 (j), 120.8 (CF , q, J 320 Hz),
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CF
121.4 (n), 121.5 (i), 121.8 (l), 128.1 (h), 135.9 (k), 147.5 (m), 149.1
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H
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3J 6.7 Hz, 12 H), 1.34 (b@, m, 24 H), 1.75 (c@, m, 8 H), 3.86 (d@,
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t, 3J 6.7 Hz, 8 H), 6.38 (e, t, 4J 2.1 Hz, 2 H), 6.52 (g, d, 4J
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eg
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Paper 8/09320B
286
New J. Chem., 1999, 275È286