Gold(I) macrocycles and topologically chiral [2]catenanes

Article abstract of DOI:10.1021/ja012006+

The design and synthesis of a new type of topologically chiral [2]catenane is reported. The compounds are formed easily by self-assembly on reaction of the oligomeric digold(I) diacetylide precursor complex [{4-BrC₆H₄CH(4-C₆

Full text of DOI:10.1021/ja012006+

Published on Web 03/21/2002
Gold(I) Macrocycles and Topologically Chiral [2]Catenanes
Christopher P. McArdle, Steve Van, Michael C. Jennings, and
Richard J. Puddephatt*
Contribution from the Department of Chemistry, UniVersity of Western Ontario, London,
Ontario N6A 5B7, Canada
Received August 20, 2001
Abstract: The design and synthesis of a new type of topologically chiral [2]catenane is reported. The
compounds are formed easily by self-assembly on reaction of the oligomeric digold(I) diacetylide precursor
complex [{4-BrC6H4CH(4-C6H4OCH2CCAu)2}n] with diphosphine ligands. Reactions with the diphosphines
PP ) bis(diphenylphosphinophoshino)acetylene, trans-1,2-bis(diphenylphosphino)ethylene, bis(diphe-
nylphosphino)ethane, and 1,1′-bis(diphenylphosphino)ferrocene yield simple ring complexes [4-BrC6H4-
CH(4-C6H4OCH2CCAu)2(µ-PP)] as the only products, since the spacer groups in the diphosphines are not
long enough or are too bulky to allow catenane formation. Reaction with PP ) bis(diphenylphosphino)-
propane or bis(diphenylphosphino)butane gave [2]catenane complexes [{4-BrC6H4CH(4-C6H4OCH2CCAu)2-
(µ-PP)}2], whose structures are confirmed crystallographically. The macrocyclic ring compounds have Cs
symmetry but, as a result of the presence of the unsymmetrical “hinge group” 4-BrC6H4CH, the [2]catenanes
have C2 symmetry and so are topologically chiral. In favorable cases, the formation of the [2]catenane can
be proved by NMR spectroscopy since catenane formation leads to nonequivalence of most ring atoms.
The formation of the [2]catenanes was successfully predicted based on the conformation of the precursor
bis(phenol), and it is argued that the methods used should be more generally applicable to the synthesis
of functionally substituted supermolecules of interest for application in molecular devices.
Introduction
organometallic catenanes by self-assembly from the components
[{X(C6H4OCH2CCAu)2}n], an oligomeric digold(I) diacetylide,
The chemistry of interlocked moleculesscatenanes, rotaxanes,
and knotssis enjoying a period of remarkable growth, since
the advent of new and improved synthetic strategies allows the
isolation and characterization of increasingly intricate structural
motifs.1,2 Self-assembly from simple precursor molecules is the
optimum synthetic method for these “supermolecules”, and so
a fundamental understanding of the self-assembly process is a
vital step with respect to the potential application of these new
molecules in the development of nanotechnology.3
and Ph2P(CH2)nPPh2, a diphosphine ligand.5 Systematic inves-
tigation of this unusual self-assembly system showed that the
number of methylene spacer groups n in the diphosphine ligand
Ph2P(CH2)nPPh2 and the nature of the hinge group X are key
factors in determining if the self-assembly will give a simple
ring by 1 + 1 assembly, a [2]catenane by 2 + 2 assembly, or
a doubly braided [2]catenane by 4 + 4 assembly (Scheme 1).6
The selectivity is determined by thermodynamic rather than
kinetic factors in most cases, and the molar masses are most
reliably determined by X-ray structure determinations though
Recent work on the synthesis of organogold(I) rings, oligo-
mers, and polymers4 led to the discovery of the first family of
* Address correspondence to this author. E-mail: pudd@julian.uwo.ca.
(1) For recent reviews see: (a) Molecular Catenanes, Rotaxanes and Knots;
Sauvage, J.-P., Dietrich-Buchecker, C. O., Eds.; Wiley-VCH: Weinheim,
Germany, 1999. (b) Fujita, M. Acc. Chem. Res. 1999, 32, 53. (c) Raymo,
F. M.; Stoddart, J. F. Chem. ReV. 1999, 99, 1643. (d) Leininger, S.; Olenyuk,
B.; Stang, P. J. Chem. ReV. 2000, 100, 853. (e) Batten, S. R.; Robson, R.
Angew. Chem., Int. Ed. Engl. 1998, 37, 1460. (f) Swiegers, G. F.; Malefetse,
T. J. Chem. ReV. 2000, 100, 3483. (g) Vo¨gtle, F.; Du¨nnwald, T.; Schmidt,
T. Acc. Chem. Res. 1996, 29, 451.
(2) (a) Reuter, C.; Wienand, W.; Schmuck, C.; Vo¨gtle, F. Chem. Eur. J. 2001,
7, 1728. (b) Safarowsky, O.; Nieger, M.; Fro¨hlich, R.; Vo¨gtle, F. Angew.
Chem., Int. Ed. 2000, 39, 1616. (c) Jimenez, M. C.; Dietrich-Buchecker,
C.; Sauvage, J.-P.; de Cian, A. Angew. Chem., Int. Ed. 2000, 39, 1295. (d)
Fujita, M.; Fujita, N.; Ogura, K.; Yamaguchi, K. Nature 1999, 400, 52. (e)
Roh, S.-G.; Park, K.-M.; Park, G.-J.; Sakamoto, S.; Yamaguchi, K.; Kim,
K. Angew. Chem., Int. Ed. Engl. 1999, 38, 638. (f) Zhang, Q.; Hamilton,
D. G.; Feeder, N.; Teat, S. J.; Goodman, J. M.; Sanders, J. K. M. New J.
Chem. 1999, 23, 897. (g) Wiseman, M. R.; Marsh, P. A.; Bishop, P. T.;
Brisdon, B. J.; Mahon, M. F. J. Am. Chem. Soc. 2000, 122, 12598. (h)
Cabezon, B.; Cao, J.; Raymo, F. M.; Stoddart, J. F.; White, A. J. P.;
Williams, D. J. Angew. Chem., Int. Ed. 2000, 39, 148.
(3) (a) Sauvage, J.-P. Science 2001, 291, 2105. (b) Ashton, P. R.; Ballardini,
R.; Balzani, V.; Credi, A.; Dress, K. R.; Ishow, E.; Kleverlaan, C. J.; Kocian,
O.; Preece, J. A.; Spencer, N.; Stoddart, J. F.; Venturi, M.; Wenger, S.
Chem. Eur. J. 2000, 6, 3558. (c) Collier, C. P.; Mattersteig, G.; Wong, E.
W.; Luo, Y.; Beverly, K.; Sampaio, J.; Raymo, F. M.; Stoddart, J. F.; Heath,
J. R. Science 2000, 289, 1172. (d) Balzani, V.; Credi, A.; Raymo, F. M.;
Stoddart, J. F. Angew. Chem., Int. Ed. Engl. 2000, 39, 3348. (e) Collier, C.
P.; Wong, E. W.; Belohradsky, V.; Raymo, F. M.; Stoddart, J. F.; Kuekes,
P. J.; Williams, R. S.; Heath, J. R. Science 1999, 285, 391. (f) Blanco, M.
J.; Jimenez, M. C.; Chambron, V.; Heitz, V.; Linke, M.; Sauvage, J.-P.
Chem. Soc. ReV. 1999, 28, 293.
(4) (a) Hunks, W. J.; Jennings, M. C.; Puddephatt, R. J. Inorg. Chem. 1999,
38, 5930. (b) Puddephatt, R. J. J. Chem. Soc., Chem. Commun. 1998, 1055.
(c) Irwin, M. J.; Vittal, J. J.; Puddephatt, R. J. Organometallics 1997, 16,
3541. (d) Irwin, M. J.; Manojlovic-Muir, Lj.; Muir, K. W.; Puddephatt, R.
J.; Yufit, D. S. J. Chem. Soc., Chem. Commun. 1997, 219.
(5) McArdle, C. P.; Irwin, M. J.; Jennings, M. C.; Puddephatt, R. J. Angew.
Chem., Int. Ed. Engl. 1999, 38, 3376.
(6) (a) McArdle, C. P.; Vittal, J. J.; Puddephatt, R. J. Angew. Chem., Int. Ed.
2000, 39, 3819. (b) McArdle, C. P.; Jennings, M. C.; Vittal, J. J.;
Puddephatt, R. J. Chem. Eur. J. 2001, 7, 3572.
9
10.1021/ja012006+ CCC: $22.00 © 2002 American Chemical Society
J. AM. CHEM. SOC. 2002, 124, 3959-3965
3959

A R T I C L E S
McArdle et al.
Scheme 1
Figure 1. Top: Conformations of X(C6H4O)2 groups that, in the digold(I)
complexes [{X(4-C6H4OCH2CtCAu)2(µ-Ph2P(CH2)4PPh2)}x], favor [2]-
catenane (A and B), simple ring (C), or doubly braided catenane (D)
formation. Bottom: The structure of the precursor compound 1 in which
the corresponding angles are 85° and 54°, close to A and so expected to
favor [2]catenane formation.
MALDI-TOF or ESI MS can give useful data in favorable
instances.5,6
Formation of the [2]catenane was favored for n ) 3 or 4,
and for hinge groups X which gave conformations of the
X(C6H4O)2 units close to A or B (Figure 1, X ) CH2 or CMe2),
rather than C (simple ring formation, X ) O or S) or D (doubly
braided [2]catenane formation, X ) cyclohexylidene).6 A key
test of the value of this correlation is to determine if it can be
used predictively in the design of functional [2]catenanes. This
article reports the application to the design of chiral [2]catenanes.
Although there is intense interest in chiral supermolecules,7 the
first report of a topologically chiral [2]catenane still represents
the state of the art.8 In that work, the asymmetry resulted from
in-plane substitution in the macrocyclic ring E (Figure 2),
whereas in the present work, out-of-plane substitution is
introduced through the unsymmetrical hinge group 4-bromophe-
nylmethylene as shown in F (Figure 2). In both cases, the
resulting [2]catenane is C2 symmetric and chiral, whereas a
single ring is Cs symmetric and achiral. However, there are
important differences in terms of the symmetry of atoms in and
Figure 2. Two rings that can give topologically chiral [2]catenanes. E
and F each have Cs symmetry, but the mirror plane lies in the ring plane
in E and perpendicular to the ring plane in F. G and H are the corresponding
topologically chiral [2]catenanes, each with C2 symmetry. Nonequivalent
CH2 protons are indicated as a,b or, in the [2]catenanes, a,a′; b,b′.
(7) (a) Kihara, N.; Tanaka, T. J. Synth. Org. Chem. Jpn. 2001, 59, 206. (b)
Hubin, T. J.; Busch, D. H. Coord. Chem. ReV. 2000, 200, 5. (c) Reuter,
C.; Mohry, A.; Sobanski, A.; Vogtle, F. Chem. Eur. J. 2000, 6, 1674. (d)
Dietrich-Buchecker, C.; Rapenne, G.; Sauvage, J. P.; de Cian, A.; Fischer,
J. Chem. Eur. J. 1999, 5, 1432. (e) Ashton, P. R.; Heiss, A. M.; Pasini, D.;
Raymo, F. M.; Shipway, A. N.; Stoddart, J. F.; Spencer, N. Eur. J. Org.
Chem. 1999, 995.
(8) (a) Mitchell, D. K.; Sauvage, J.-P. Angew. Chem., Int. Ed. Engl. 1988, 27,
930. (b) Chambron, J.-C.; Mitchell, D. K.; Sauvage, J.-P. J. Am. Chem.
Soc. 1992, 114, 4625.
out of the ring plane as illustrated in Figure 2 for pairs of CH2
groups. The two ring types shown in Figure 2 are thus
complementary, and each represents a simple way to obtain
topologically chiral [2]catenanes.
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3960 J. AM. CHEM. SOC. VOL. 124, NO. 15, 2002

Gold(I) Macrocycles and Topologically Chiral[2] Catenanes
A R T I C L E S
Scheme 2
Figure 3. A view of the structure of the [2]catenane complex 5a. Selected
bond distances (Å) and angles (deg): Au(1)-Au(3) 3.1937(6); Au(2)-
Au(4) 3.1409(6); Au(1)-C(11) 2.02(1); Au(2)-C(21) 2.00(1); Au(3)-C(31)
2.01(1); Au(4)-C(41) 2.00(1); Au(1)-P(1) 2.272(4); Au(2)-P(2) 2.280-
(3); Au(3)-P(3) 2.270(3); Au(4)-P(4) 2.266(4) C; C(11)-Au(1)-P(1)
171.8(3); C(21)-Au(2)-P(2) 171.0(3); C(31)-Au(3)-P(3) 169.7(3); C(41)-
Au(4)-P(4) 174.3(3).
the gold(I) centers in 3. Compound 3 reacted with diphosphine
ligands to yield macrocyclic organogold(I) complexes (Scheme
2), by replacement of the gold-alkyne π-bonds by the stronger
phosphine donors. The challenge is to determine if the simple
ring, 4, or singly braided [2]catenane, 5, or other products are
formed by the self-assembly process.
Macrocyclic Complexes. Reaction of 3 with the diphosphines
bis(diphenylphosphino)acetylene, trans-1,2-bis(diphenylphos-
phino)ethylene, bis(diphenylphosphino)ethane, and 1,1′-bis-
(diphenylphosphino)ferrocene yield simple ring complexes
4a-d as the only products (Scheme 2). In these cases, the spacer
groups are not long enough or are too bulky to allow catenane
formation. In each case, the 31P NMR spectrum contains only
a singlet resonance, and the 1H and 13C NMR spectra are
consistent with the expected Cs symmetry. For example,
complex 4c gave single resonances for the alkynyl carbon atoms
at δ(13C) ) 97.53 [CtC-Au] and 132.00 [CtC-Au] and the
observation of phosphorus-carbon coupling proves the presence
of PAuCC units. However, the expected nonequivalence of out-
of-ring-plane atoms (Figure 2) was not resolved. For example,
the OCHaHb protons gave a single resonance δ(1H) ) 4.78 [s,
4H, OCH2] and only one set of phenyl resonances was observed
for the PPhaPhb groups in the 13C NMR spectrum. The structure
of 4a was confirmed by a partial structure determination, but
poor quality data did not allow a full refinement.
[2]Catenanes. Reaction of 3 with bis(diphenylphosphino)-
propane gave a mixture of products: a simple ring 4e, a [2]-
catenane 5a, and a small amount of a third complex 6, whose
structure is unknown. The (CH2)3 spacer-group is only just long
enough to allow catenation to occur, and an equilibrium exists
between the three products. Recrystallization of the reaction
mixture gave pure [2]catenane 5a, whose structure is shown in
Figure 3. The two-component 24-membered rings of the
catenane are tightly entwined, as evidenced by the presence of
two strong intramolecular aurophilic interactions [Au(1)-Au-
(3) ) 3.1937(6) Å; Au(2)-Au(4) ) 3.1409(6) Å].11 The phenol
twist angles in the catenane [84.1 and 45.3° in one ring, 93.6
and 47.3° in the other] are comparable to those in the parent
bisphenol 1. This provides further support for the proposal that
it is the aryl conformations that direct the self-assembly process
and not vice versa. The solid-state structure also illustrates the
Results
The Precursor Complexes. The bisphenol derivative (4-
bromophenyl)bis(4-hydroxyphenyl)methane (1) was synthesized
by the acid catalyzed condensation of phenol and 4-bromoben-
zaldehyde.9 The structure of 1 is shown in Figure 1. It adopts
a propeller conformation, with the two phenol rings twisted at
angles of 54 and 85° with respect to the hinge plane (plane
defined by the hinge carbon atom and its two bonded ipso
carbon atoms, Figure 1). On the basis of the empirical correlation
previously established,6 the orientation of the phenol groups in
this parent bis(phenol) is close to the ideal conformation A
(Figure 1) for the formation of singly braided [2]catenanes from
the propargylgold(I) derivatives which are formed as shown in
Scheme 2. Another important feature of bis(phenol) 1 is the
presence of nonequivalent groups on the hinge carbon atom [H
and 4-C6H4Br], which will give a catenated product with C2
symmetry.
The synthesis of the bis(propargyl) derivative 4-BrC6H4CH-
(4-C6H4OCH2CCH)2, 2, and then the oligomeric digold(I)
diacetylide [{4-BrC6H4CH(4-C6H4OCH2CCAu)2}n], 3, was
straightforward.5,6 Such gold(I) acetylides are oligomeric or
polymeric, with both σ and π bonds from gold to the alkynyl
groups, and the resulting insolubility makes structural charac-
terization difficult.10 Evidence for the proposed structural type
is seen in the IR spectrum which shows ν(CtC) ) 2010 cm-1
,
a reduction of 113 cm-1 compared to the parent bis(alkyne) 2,
as a consequence of the alkynyl group acting as a π-donor to
(9) Driver, J. E.; Lai, T. F. J. Chem. Soc. 1958, 3219.
(10) Mingos, D. M. P.; Yau, J.; Menzer, S.; Williams, D. J. Angew. Chem., Int.
Ed. Engl. 1995, 34, 1894.
(11) (a) Schmidbaur, H.; Grohmann, A.; Olmos, M. E. In Gold: Progress in
Chemistry, Biochemistry and Technology; Schmidbaur, H., Ed.; Wiley:
Chichester, 1999. (b) Pyykko¨, P. Chem. ReV. 1997, 97, 597.
9
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A R T I C L E S
McArdle et al.
Figure 5. A view of the structure of the [2]catenane complex 5b. Selected
bond distances (Å) and angles (deg): Au(1)-C(11) 2.02(1); Au(2)-C(21)
2.02(1); Au(3)-C(31) 2.01(1); Au(4)-C(41) 1.99(1); Au(1)-P(1) 2.279-
(2); Au(2)-P(2) 2.270(2); Au(3)-P(3) 2.271(2); Au(4)-P(4) 2.270(2) C;
C(11)-Au(1)-P(1) 174.1(3); C(21)-Au(2)-P(2) 178.1(3); C(31)-Au(3)-
P(3) 178.3(3); C(41)-Au(4)-P(4) 171.0(3).
Figure 4. 31P NMR spectra of complexes 5a and 5b. (a) The analogy
between chiral allene and topologically chiral [2]catenane and the non-
equivalence of phosphorus atoms P, P′ in the [2]catenane 5a. (b) The
variable-temperature 31P NMR spectra of [2]catenane 5bsevidence for two
easily equilibrating conformers, one giving a singlet and the other giving
two singlets.
atoms are sufficiently remote from the source of asymmetry
that the two different phosphorus environments are effectively
degenerate. The increased flexibility compared to 5a might be
a factor and, in an attempt to slow these molecular motions,
low-temperature 31P NMR of 5b were recorded in 50:50 CD2-
Cl2/CHFCl2 and are illustrated in Figure 4b. As the solution of
5b is cooled the singlet broadens but, even at -120 °C, the
main resonance does not split. However, at the lowest temper-
atures two new peaks δ 38.09 and 32.83 grow in, and the
original singlet sharpens at -120 °C. It is likely that the new
resonances are due to another catenane “conformer”, perhaps
one that is similar to the structure of 5a, with closer Au‚‚‚Au
interactions that help to differentiate the 31P environments. The
relative intensities of the 31P resonances in the temperature range
-100 to -120 °C were independent of the concentration of
5b, thus showing that the two forms have the same molecular
approximate C2 symmetry of the catenane, a result of the
presence of inequivalent groups on the hinge carbon atom. The
lack of mirror symmetry in 5a is expected to lead to nonequiva-
lence of ring atoms that would be equivalent in a simple
macrocyclic structure, and this is most simply illustrated by the
31P NMR spectrum (Figure 4a). In a solution containing both
4e and 5a, a singlet was observed at δ 35.90 for the simple
ring 4e (Cs symmetry) and an AB quartet at δ 31.80 and 32.15
(4JPP ) 6 Hz) for the [2]catenane 5a (C2 symmetry). This
splitting of the phosphorus resonances on [2]catenane formation
is not observed when there is a symmetrical hinge such as CMe2
and so, when it is resolved, the effect confirms that the [2]-
catenane structure is maintained in solution. However, in the
1H NMR spectrum, the expected nonequivalence of OCHaHb
protons or PPhaPhb resonances was not resolved. For example,
the OCHaHb protons appeared as a broad resonance in the 600
1
weight. In the H NMR spectrum of 5b, the OCHaHb protons
2
appeared as a closely spaced AB quartet, J(HaHb) ) 17 Hz,
and so it seems that [2]catenane formation causes the resolution
since it was not observed for any of the simple ring complexes
4. However, the further splitting expected for the [2]catenane
(Figure 2) was not resolved.
1
MHz H NMR spectrum.
The reaction of complex 3 with bis(diphenylphosphino)butane
was expected to give a [2]catenane selectively since the (CH2)4
spacer group in the diphosphine and the conformation of the
phenol groups are both optimized for this reaction. Indeed, the
reaction occurred selectively to give complex 5b in high yield,
and a structure determination confirmed that the [2]catenane
was formed selectively by the self-assembly process (Figure
5). Once again the phenol twist angles (Figure 1) are essentially
maintained from the parent bisphenol [84.9 and 35.3° in one
ring, 76.2 and 36.5° in the other]. In 5b, the interlocking of the
larger 25-membered rings occurs without formation of any very
short Au‚‚‚Au contacts [the shortest is shown in Figure 5 with
Au(1)‚‚‚Au(4) ) 3.47 Å and corresponds to a weak aurophilic
attraction11 while Au(1)‚‚‚Au(2) ) 5.15 Å, Au(2)‚‚‚Au(3) )
6.54 Å, and Au(3)‚‚‚Au(4) ) 6.54 Å are clearly nonbonding]
and so the driving force for [2]catenane formation arises
primarily from aryl-aryl attractive forces in this case. The
symmetry of the [2]catenane is approximately C2 and so, as
discussed for 5a, there are expected to be two 31P NMR
resonances, as well as a doubling of other ring resonances in
the 1H and 13C NMR spectra for 5b. However, the room
temperature 31P NMR spectrum (Figure 4b) contained only one
singlet at δ 38.86, not the two signals expected for the C2
structure. One interpretation of this observation is that the ring
Complexes 5a and 5b are chiral and are formed as racemic
mixtures. In principle, it should be possible to resolve resonances
of the enantiomers by using a chiral shift reagent. However,
the NMR spectra were not changed in the presence of the
lanthanide shift reagent tris[3-{(trifluoromethyl)hydroxymeth-
ylene}-+-camphorato]europium(III). It is likely that the phenol
oxygen atoms are too sterically hindered to coordinate to the
europium ion and so no paramagnetic shifts are observed.
The structures of 5a and 5b indicate that aryl-aryl attractions
are important in favoring [2]catenane formation.5,6 In 5b, there
are two phenyl-phenyl offset face-to-face (off) interactions,
with participating phenyl groups almost parallel, and four
phenyl-aryl vertex-to-face (vf) interactions, with participating
aryl groups essentially orthogonal.12 The closest gold‚‚‚gold
contact is Au(1)-Au(4) ) 3.47 Å, which is probably only
weakly attractive, and so the aryl-aryl interactions are the key
to [2]catenane formation in this case. In 5a, the gold‚‚‚gold
attractions are much stronger (Figure 3) but the aryl-aryl
attractions appear less favorable. There are again two phenyl-
phenyl offset face-to-face (off) interactions,12 with parallel aryl
rings separated by 4.0 Å, but four additional weaker aryl-aryl
(12) Dance, I.; Scudder, M. J. Chem. Soc., Dalton 2000, 1579.
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Gold(I) Macrocycles and Topologically Chiral[2] Catenanes
A R T I C L E S
mL) was cooled to 0 °C and a mixture of sulfuric acid (3 mL) and
acetic acid (10 mL) was added dropwise with stirring. The mixture
was kept at 0 °C for 72 h, and the product was precipitated by addition
of ice water, separated by filtration, washed with water, and vacuum-
dried overnight, then recrystallized from benzene. Yield: 1.56 g, 54%.
IR (Nujol): ν(OH) ) 3200-3500 cm-1. NMR (CD3CN, 25 °C): δ-
(1H) ) 5.38 [s, 1H, CH], 6.72 [m, 4H, C6H4O], 6.82 [s, 2H, OH], 6.90
[m, 4H, C6H4O], 7.00 [m, 2H, C6H4Br], 7.42 [m, 2H, C6H4Br]; δ(13C)
) 54.4 [s, CH], 115.3 [s, C6H4O], 119.6 [s, C6H4Br], 130.4 [s, C6H4O],
131.3 [s, C6H4Br], 131.4 [s, C6H4Br], 135.5 [s, C6H4O], 144.8 [s, C6H4-
Br], 155.6 [s, C6H4O]. Mass spectrum: m/z 356, 354 (M), 275 (loss of
Br), 199 (loss of C6H4Br).
(4-BrC6H4)CH(4-C6H4OCH2CtCH)2, 2. Finely ground KOH (0.25
g, 4.50 mmol) and BrCH2CtCH (0.50 g, 4.22 mmol) were added to a
solution of 4-BrC6H4CH(4-C6H4OH)2 (0.50 g, 1.41 mmol) in acetone
(10 mL). The mixture was refluxed for 16 h and the solution was
decolorized by activated charcoal and filtered. An oily, viscous yellow
liquid was obtained after solvent removal under reduced pressure.
interactions have nonideal orientations intermediate between
offset face-to-face (off) and edge-to-face (ef) interactions.12
Typical aryl-aryl attractions have energies of about 2 kcal/
mol, compared to 7-11 kcal/mol for Au‚‚‚Au interactions. In
5b, the aryl-aryl attractions are optimized whereas, in 5a, the
weaker aryl-aryl attractions are balanced by the presence of
two strong Au‚‚‚Au attractions. In either case, the sum of these
attractive forces is evidently sufficient to overcome the unfavor-
able entropy associated with [2]catenane formation. Any strain
in the macrocyclic rings in 5a or 5b is expected to be reflected
in distortion at the hinge carbon atoms defined by C(9)-C(8)-
C(16) ) 107.9° in the precursor bis(phenol) 1 (Figure 1). The
corresponding angles in 5a are 113.8° and 113.6° and in 5b
they are 114.1° and 111.2° in the two rings, only slightly opened
up from the natural tetrahedral angle. Thus, there is little angle
strain involved in the formation of the [2]catenanes.
The reaction of 3 with bis(diphenylphosphino)pentane gave
Yield: 0.46 g, 75%. IR (Nujol): ν(CtC) 2123 (m), 2047 (w) cm-1
.
a single complex. The 31P NMR spectrum contained only a
NMR (CD2Cl2, 25 °C): δ(1H) ) 2.56 [t, 4J(HH) ) 2 Hz, 2H, CtCH],
1
4
single resonance and the H NMR spectrum contained an AB
4.67 [d, J(HH) ) 2 Hz, 4H, OCH2], 5.42 [s, 1H, CH], 6.89 [m, 4H,
quartet for the OCHaHb protons, very similar to the observations
for 5b. Hence, the structure is expected to be the [2]catenane
5c, with effectively degenerate 31P NMR chemical shifts as for
5b, but the data do not disprove the simple ring structure.
Attempted characterization of the molar mass by MALDI-TOF
MS was unsuccessful in this case.
C6H4O], 6.99 [m, 2H, BrC6H4], 7.01 [m, 4H, C6H4O], 7.41 [m, 2H,
BrC6H4]; δ(13C) ) 54.8 [s, CH], 56.0 [s, OCH2], 75.6 [s, CtCH], 78.9
[s, CtCH], 114.9 [s, C6H4O], 120.3 [s, C6H4Br], 130.4 [s, C6H4O],
131.3 [s, C6H4Br], 131.6 [s, C6H4Br], 136. 9 [s, C6H4O], 143.8 [s, C6H4-
Br], 156.4 [s, C6H4O]. Mass spectrum: m/z 432, 430 (M), 393 and
391 (loss of CH2CtCH), 377 and 375 (loss of OCH2CtCH), 301 and
299 (loss of C6H4OCH2CtCH).
4-BrC6H4CH(4-C6H4OCH2CtCAu)2, 3. To a solution of [AuCl-
(SMe2)] (0.60 g, 2.03 mmol) in methanol (50 mL) and THF (100 mL)
was added a solution of 4-BrC6H4CH(4-C6H4OCH2CtCH)2 (0.44 g,
1.01 mmol) and NaOAc (0.25 g, 3.05 mmol) in methanol (20 mL) and
THF (20 mL). The mixture was stirred for 7 h, then the yellow
precipitate of the product was filtered and washed with THF, methanol,
diethyl ether, and pentane successively. CAUTION: The product is
shock sensitive. Yield: 0.58 g, 69%. IR (Nujol): ν (CtC) ) 2010
cm-1. Anal. Calcd for C25H17Au2BrO2: C, 36.5; H, 2.1; Br, 9.7.
Found: C, 36.1; H, 2.1; Br, 9.4.
[4-BrC6H4CH(4-C6H4OCH2CtCAu)2(µ-Ph2PCtCPPh2)], 4a. A
mixture of 4-BrC6H4CH(4-C6H4OCH2CtCAu)2 (0.15 g, 0.18 mmol)
and Ph2PCtCPPh2 (0.06 g, 0.16 mmol) in CH2Cl2 (50 mL) was stirred
at room temperature in a darkened reaction flask for 2 h. Activated
charcoal was added and the mixture was stirred for another 0.5 h. The
mixture was filtered, and the solvent was removed under reduced
pressure to give the product, which was recrystallized from CH2Cl2/
pentane. Yield 62%. IR (CH2Cl2): ν(CtC) ) 2137 cm-1. NMR (CD2-
Cl2, 25 °C): δ(1H) ) 4.80 [s, 4H, OCH2], 5.41 [s, 1H, CH], 6.99 [m,
2H, C6H4Br], 7.03 [m, 8H, C6H4O], 7.40 [m, 2H, C6H4Br], 7.48-7.76
[m, 20H, Ph]; δ(31P) ) 18.7 [s]; δ(13C) ) 55.1 [s, CH], 56.6 [s, OCH2],
97.8 [s, CtCAu], 101.5 [m, CtC], 115.3 [s, C6H4O], 120.2 [s, C6H4-
Discussion
This work has demonstrated that, for this series of organogold
macrocycles, it is possible to predict the topology of the self-
assembly products through consideration of both the starting
organic bis(phenol) fragment and the choice of phosphine ligand.
Furthermore, the catenanes are topologically chiral and the
synthesis by self-assembly is particularly easy. Topologically
chiral [2]catenanes have been prepared previously by the
Sauvage group,8 and this work is complementary since the
symmetry planes of the individual rings in the two classes of
compounds are perpendicular to one another, and so the NMR
properties of the [2]catenanes are distinct. In the case of complex
5a, the [2]catenane can be identified by 31P NMR spectroscopy
in solution as a result of the dissymmetry induced by catenane
formation.
The factors that control the self-assembly processes are subtle
but this work has shown that, at least within closely related
series of compounds, it is possible to predict the nature of the
self-assembly and so to use it to prepare functional materials.
It is anticipated that further application of the principles outlined
here will allow the design and synthesis of more complex
molecular structures, in particular, functionalized [2]catenanes
and poly-[2]catenanes.
1
2
Br], 128.2 [d, J(PC) ) 62 Hz, Ph], 129.9 [d, J(PC) ) 12 Hz, Ph],
130.3 [s, C6H4O], 131.4 [s, C6H4Br], 131.5 [s, C6H4Br], 132.5 [d, 2J(PC)
) 155 Hz, CtCAu], 132.8 [s, Ph], 133.6 [d, J(PC) ) 11 Hz, Ph],
3
136.3 [s, C6H4O], 144.4 [s, C6H4Br], 156.7 [s, C6H4O]. Anal. Calcd
for C48H35Au2BrO2P2: C, 48.9; H, 3.0; Br, 6.8. Found: C, 48.3; H,
2.5; Br, 6.4.
Experimental Section
All gold complexes were protected from light by using darkened
reaction flasks. NMR spectra were recorded by using Varian Mercury
400 MHz and Inova 600 MHz spectrometers. 1H and 13C NMR chemical
shifts are reported relative to tetramethylsilane, and 31P chemical shifts
relative to the 85% H3PO4 as an external standard. IR spectra were
recorded by using a Perkin-Elmer 2000 FTIR as Nujol mulls on KBr
plates or as CH2Cl2 solutions in solution cells. Mass spectra were
recorded with a Finnigan MAT 8200 spectrometer.
Similarly prepared were the following:
[4-BrC6H4CH(4-C6H4OCH2CtCAu)2(µ-trans-Ph2PCHd
CHPPh2)], 4b. Yield 60%. IR (CH2Cl2): ν(CtC) ) 2137 cm-1, ν
(CdC) ) 1600 cm-1. NMR (CD2Cl2, 25 °C): δ(1H) ) 4.79 [s, 4H,
OCH2], 5.41 [s, 1H, CH], 6.87 [m, 2H, CHdCH], 7.00 [m, 2H, C6H4-
Br], 7.04 [m, 8H, C6H4O], 7.40 [m, 2H, C6H4Br], 7.52 [m, 20H, Ph];
δ(31P) ) 39.50 [s]; δ(13C) ) 55.1 [s, CH], 56.6 [s, OCH2], 97.6 [m,
CtCAu], 115.4 [s, C6H4O], 120.2 [s, C6H4Br], 128.2 [m, Ph], 129.9
[s, Ph], 130.3 [s, C6H4O], 130.6 [m, CbtCAu], 131.4 [s, C6H4Br], 131.5
[s, C6H4Br], 132.6 [s, Ph], 134.3 [s, Ph], 136.3 [s, C6H4O], 141.0 [m,
(4-BrC6H4)CH(4-C6H4OH)2, 1. A solution of p-bromobenzaldehyde
(1.50 g, 8.1 mmol) and phenol (1.72 g, 18 mmol) in acetic acid (3
9
J. AM. CHEM. SOC. VOL. 124, NO. 15, 2002 3963

A R T I C L E S
McArdle et al.
Table 1. Crystal and Structure Refinement Data
1‚1.5C H
5a‚C H ‚H O
5b‚1/2C H O‚3/2CH Cl2
4 10 2
6
6
5
12
2
formula
fw
C28H24BrO2
472.38
C57H54.5Au2BrO3P2
1323.29
C56.5H53Au2BrCl3O2.5P2
1414.12
temp/K
200(2)
150(2)
150(2)
λ/Å
0.71073
monoclinic
P2(1)/c
13.8604(4)
18.4059(8)
9.3622(3)
90
102.925(2)
90
2327.9(1), 4
1.348
0.71073
monoclinic
P2(1)/n
20.1462(4)
12.8256(2)
39.3165(7)
90
99.197(1)
90
0.71073
triclinic
P1h
crystal system
space group cell dimens.
a/Å
11.2137(3)
20.7128(7)
24.6213(7)
104.052(2)
93.098(2)
102.873(2)
5372.7(3), 4
1.748
b/Å
c/Å
R/deg
â/deg
γ/deg
V/Å3, Z
10028.3(3), 8
1.753
6.749
d(calcd)/mg/m3
abs. coeff./mm-1
F(000)
1.787
972
6.449
2744
5148
θ range/deg
no. of reflcns/ind. reflcns
abs. corr.
no. of data/restr/param
goof
2.64-27.48
24120/5310
Integration
5310/0/282
0.893
2.56-27.50
81751/22888
Integration
22888/14/1015
0.933
2.58-27.50
52288/23138
Integration
23138/41/1108
0.946
R1, wR2 [I>2σ(I)]
R1, wR2 (all data)
0.041, 0.086
0.111, 0.101
0.059, 0.146
0.149, 0.165
0.057, 0.132
0.112, 0.148
CdC], 144.2 [s, C6H4Br], 156.7 [s, C6H4O]. Anal. Calcd for C48H37-
Au2BrO2P2: C, 48.8; H, 3.2; Br, 6.8. Found: C, 48.8; H, 3.0; Br, 6.5.
[4-BrC6H4CH(4-C6H4OCH2CtCAu)2(µ-Ph2P(CH2)2PPh2)], 4c.
Yield: 73%. IR (CH2Cl2): ν(CtC) 2136 cm-1. NMR (CD2Cl2, 25
°C): δ(1H) ) 2.51 [m, 4H, CH2], 4.79 [s, 4H, OCH2], 5.40 [s, 1H,
CH], 7.01 [m, 2H, C6H4Br], 7.03 [m, 4H, C6H4O], 7.09 [m, 4H, C6H4O],
7.39 [m, 2H, C6H4Br], 7.44-7.52 [m, 20H, Ph]; δ(31P) ) 40.4 [s];
δ(13C) ) 23.9 [m, CH2], 55.2 [s, CH], 56.6 [s, OCH2], 97.5 [m, Ct
CAu], 115.5 [s, C6H4O], 120.2 [s, C6H4Br], 129.3 [m, Ph], 129.7 [m,
Ph], 130.2 [s, C6H4O], 131.3 [s, C6H4Br], 131.5 [s, C6H4Br], 132.0
[m, CtCAu], 132.4 [s, Ph], 133.6 [m, Ph], 136.4 [s, C6H4O], 144.0 [s,
C6H4Br], 156.6 [s, C6H4O). Anal. Calcd for C48H39Au2BrO2P2: C, 48.7;
H, 3.3; Br, 6.7. Found: C, 48.6; H, 3.4; Br, 6.4.
2J(HH) ) 17 Hz, 8H, OCH2], 5.40 [s, 2H, CH], 6.99 [m, 4H, C6H4Br],
7.02 [m, 8H, C6H4O], 7.07 [m, 8H, C6H4O], 7.39 [m, 4H, C6H4Br],
7.45-7.62 [m, 40H, Ph]; δ(31P) ) 38.9 [s]; δ(13C) ) 27.6 [m, CH2],
28.0 [d, 1J(PC) ) 34 Hz, CH2], 55.1 [s, CH], 56.8 [s, OCH2], 97.5 [d,
3J(PC) ) 27 Hz, CtCAu], 115.3 [s, C6H4O], 120.1 [s, C6H4Br], 129.5
1
[m, Ph], 130.3 [s, C6H4O], 130.6 [d, J(PC) ) 54 Hz, Ph], 131.3 [s,
C6H4Br], 131.5 [s, C6H4Br], 131.9 [s, Ph], 132.2 [d, 2J(PC) ) 143 Hz,
CtCAu], 133.6 [m, Ph], 136.2 [s, C6H4O], 144.4 [s, C6H4Br], 156.8
[s, C6H4O]. Anal. Calcd for C100H86Au4Br2O4P4: C, 49.6; H, 3.6; Br,
6.6. Found: C, 49.8; H, 3.6; Br, 7.0.
[4-BrC6H4CH(4-C6H4OCH2CtCAu)2(µ-Ph2P(CH2)5PPh2)], 5c.
Yield 77%. IR (CH2Cl2): ν(CtC) ) 2134 cm-1. NMR (CD2Cl2, 25
°C): δ(1H) ) 1.54 [m, 12H, CH2], 2.34 [m, 8H, CH2], 4.76, 4.78 [AB
q, 2J(HH) ) 18 Hz, 8H, OCH2], 5.42 [s, 2H, CH], 7.01 [m, 4H, C6H4-
Br], 7.03 [m, 16H, C6H4O], 7.40 [m, 4H, C6H4Br], 7.45-7.65 [m, 40H,
[4-BrC6H4CH(4-C6H4OCH2CtCAu)2{µ-(Ph2PC5H4)2Fe}], 4d. Yield
70%. IR (CH2Cl2): ν(CtC) ) 2134 cm-1. NMR (CD2Cl2, 25 °C):
δ(1H) ) 4.38 [m, 10H, C5H4], 4.84 [s, 4H, OCH2], 5.40 [s, 1H, CH],
7.02 [m, 2H, C6H4Br], 7.07 [m, 8H, C6H4O], 7.40 [m, 2H, C6H4Br],
7.44-7.54 [m, 20H, Ph]; δ(31P) ) 37.1 [s]; δ(13C) ) 55.1 [s, CH],
2
Ph]; δ(31P) ) 37.5 [s]; δ(13C) ) 25.8 [d, J(PC) ) 5 Hz, CH2], 28.1
[d, 1J(PC) ) 34 Hz, CH2], 33.0 [m, CH2], 55.0 [s, CH], 56.8 [s, OCH2],
97.5 [d, 3J(PC) ) 26 Hz, CtCAu], 115.3 [s, C6H4O], 120.1 [s, C6H4-
3
3
Br], 127.5 [d, J(PC) ) 11 Hz, Ph], 130.3 [s, C6H4O], 130.9 [m, Ph],
57.0 [s br, OCH2], 72.1 [m br, C5H4], 75.1 [d, JPC ) 8 Hz, C5H4],
2
2
131.4 [s, C6H4Br], 131.5 [s, C6H4Br], 131.8 [s, Ph], 132.1 [d, J(PC)
75.4 [d, JPC ) 13 Hz, C5H4], 97.8 [s, CtCAu], 115.3 [s, C6H4O],
) 143 Hz, CtCAu], 133.6 [d, 2J(PC) ) 13 Hz, Ph], 136.2 [s, C6H4O],
144.4 [s, C6H4Br], 156.9 [s, C6H4O]. Anal. Calcd for C102H90Au4-
Br2O4P4: C, 50.0; H, 3.7; Br, 6.5. Found: C, 48.1; H, 3.7; Br, 7.5.
X-ray Structure Determinations. Crystals of [(4-BrC6H4)CH(4-
C6H4OH)2]‚3/2benzene, 1, were grown from benzene solution. An orange
prism was mounted on a glass fiber. Data were collected at low
temperature (-73 °C) by using a Nonius Kappa-CCD diffractometer
with COLLECT (Nonius, 1998) software. The unit cell parameters were
calculated and refined from the full data set. Crystal cell refinement
and data reduction was carried out with use of the Nonius DENZO
package. The data were scaled by using SCALEPACK (Nonius, 1998)
and no other absorption corrections were applied. The crystal data and
refinement parameters are listed in Table 1. The reflection data and
systematic absences were consistent with the monoclinic space group
P2(1)/c. The SHELXTL 5.1 (Sheldrick, G. M., Madison, WI) program
package was used to solve the structure by direct methods, followed
by successive difference Fouriers. All non-hydrogen atoms were refined
with anisotropic thermal parameters.
120.2 [s, C6H4Br], 129.0 [m, Ph], 129.3 [d, 3J(PC) ) 11 Hz, Ph], 130.4
2
[s, C6H4O], 131.4 [s, C6H4Br], 131.5 [s, C6H4Br], 131.7 [d, J(PC) )
2
56 Hz, CtCAu], 131.8 [s, Ph], 134.0 [d, J(PC) ) 15 Hz, Ph], 136.3
[s, C6H4O], 144.3 [s, C6H4Br], 157.0 [s, C6H4O]. Anal. Calcd for C56H43-
Au2BrFeO2P2: C, 50.2; H, 3.2; Br, 6.0. Found: C, 50.3; H, 3.0; Br,
5.9.
[{4-BrC6H4CH(4-C6H4OCH2CtCAu)2(µ-Ph2P(CH2)3PPh2)}2], 5a.
Yield 64%. IR (CH2Cl2): ν(CtC) ) 2134 cm-1. The initial product is
a mixture of isomers but recrystallization gave the pure [2]catenane,
whose data are given. NMR (CD2Cl2, 25 °C): δ(1H) ) 1.68 [m, 8H,
CH2], 2.20 [m, 4H, CH2], 4.57 [m br, 8H, OCH2], 5.26 [s, 2H, CH],
6.09 [m, 4H, C6H4O], 6.11 [m, 4H, C6H4O], 6.54 [m, 8H, C6H4O],
6.63 [m, 4H, BrC6H4], 7.18 [m, 4H, BrC6H4], 7.26-7.50 [m, 40H, Ph];
δ(31P) ) 31.98 [AB quartet, J(PP) ) 6 Hz]. Anal. Calcd for C98H81-
Au4Br2O4P4: C, 49.1; H, 3.4; Br, 6.7. Found: C, 49.2; H, 3.6; Br, 6.3.
The 31P NMR spectrum of the initial product contained additional
resonances at δ(31P) ) 35.90 [s, simple ring 4e], and weaker peaks at
δ(31P) ) 31.80, 32.15 [br, unknown complex 6]; the pure catenane in
solution reverted to the equilibrium mixture over a period of 2 days.
[{4-BrC6H4CH(4-C6H4OCH2CtCAu)2(µ-Ph2P(CH2)4PPh2)}2], 5b.
Yield 72%. IR (CH2Cl2): ν(CtC) 2134 cm-1. NMR (CD2Cl2, 25 °C):
δ(1H) ) 1.73 [m, 8H, CH2], 2.35 [m, 8H, CH2], 4.76, 4.80 [AB q,
Crystals of [{4-BrC6H4CH(4-C6H4OCH2CtCAu)2(µ-Ph2P(CH2)3-
PPh2)}2] ‚2pentane‚2H2O were grown by slow diffusion of pentane into
a CH2Cl2 solution, and a colorless crystal was mounted on a glass fiber.
Data were collected at low temperature (-123 °C) and treated as above.
9
3964 J. AM. CHEM. SOC. VOL. 124, NO. 15, 2002

Gold(I) Macrocycles and Topologically Chiral[2] Catenanes
A R T I C L E S
The reflection data and systematic absences were consistent with the
monoclinic space group P2(1)/n. All the non-hydrogen atoms were
refined anisotropically. The two pentanes of solvation were modeled
isotropically with fixed C-C bond lengths. The hydrogen atoms were
calculated geometrically and were riding on their respective carbon
atoms. The two water molecules were modeled as isotropic oxygen
atoms.
Crystals of [{4-BrC6H4CH(4-C6H4OCH2CtCAu)2(µ-Ph2P(CH2)4-
PPh2)}2]‚1Et2O‚3CH2Cl2 were grown by slow diffusion of ether into a
CH2Cl2 solution. A colorless plate was cut and mounted on a glass
fiber. Data were collected at -123 °C and treated as above. The
reflection data were consistent with the triclinic space group P1h. All
the non-hydrogen atoms were refined anisotropically. The ether of
solvation was modeled anisotropically with fixed C-C and C-O bond
lengths. Two of the methylene chlorides were modeled anisotropically
with fixed C-Cl bond lengths [1.65 Å]. The third methylene chloride
was disordered over two sites and was modeled as a 50/50 isotropic
mixture with fixed C-Cl bond lengths [1.65 Å] and Cl-Cl bond lengths
[2.74 Å]. The hydrogen atoms were calculated geometrically and were
riding on their respective carbon atoms.
Acknowledgment. We thank the NSERC (Canada) for
financial support and R.J.P. thanks the Government of Canada
for a Canada Research Chair.
Supporting Information Available: Tables of X-ray data for
compounds 1, 5a,and 5b (PDF). This material is available free
of charge via the Internet at http://pubs.acs.org.
JA012006+
9
J. AM. CHEM. SOC. VOL. 124, NO. 15, 2002 3965