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Functionalized Oligocyclic Large Cavities Ч A Novel Siderophore.

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[ I ] a) K. Odashima, A. Itai, Y. Iitaka, Y. Arata, K. Koga, Tefrahedrun Left.
21 (1980) 4347; K. Odashima, K. Koga: Cyelophanes, Vu/. 2, Academic
Press, New York 1983, S. 629; b) F. Diederich, K. Dick, Angew. Chem. 95
(1983) 730; Angew. Chem. In[. Ed. Engl. 22 (1983) 715; Angew. Chem.
Supp/. 1983, 957; c) H . J. Schneider, personal communication; d) J.
Winkler, E. Coutouli-Argyropoulou, R. Leppkes, R. Breslow, J . Am.
Chem. Sue. 105 (1983) 7198; e) Y. Murakami, Top. Curr. Chem. 115
(1983) 107; f) cf. 1. Tabushi, K. Yamamura, ibid. l l 3 (1983) 145; g) cf.
also C. J. Suckling, J . Chem. SOC.Chem. Cummun. 1982, 661.
[2] Correct elemental analyses, ‘H-NMR, and mass spectra were obtained
for all the new compounds.
[31 The shifts arise from anisotropic effects between host and guest as well as
from the influences of the positive charges on the pyridinium groups; cf.
[Ib, cl.
141 Since 2 ( R = benzyl), in contrast to 2a-c, is not soluble in acids, analogous inclusions in water are ruled out; cf. F. Vogtle, H . Puff, E. Friedrichs, W. M. Miiller, J . Chem. Sue. Chem. Commun. 1982, 1398.
151 Prof. K . Koga, Kyoto, is thanked for this personal communication.
[6] Cf. G. W. Kirby, L. Ogunkoya, J. Chem. SUC.1965. 69 14, and references
cited thcrcin.
171 Attempts to hydrolyze lipophilic p-nitrophenyl esters in the presence of
2a, b as catalyst in aqueous acidic solution indicate an inhibition attributable either to a strong host/guest binding or to an unfavorable position of the nucleophilic centers of the host.
[Sl Cf. R. M. Kellogg, Top. Curr. Chem. I01 (1982) 1 11.
Functionalized, Oligocyclic Large CavitiesA Novel Siderophore“”
290 “C) dissolves remarkably readily in chloroform, but
less well in dichloromethane.
The ‘H-NMR spectrum reflects the symmetry of the mol e ~ u l e [The
~ ~ .singlet of the methoxy protons is shifted characteristically to high field. On the NMR time scale, the
OCH3 groups apparently rotate relatively unhindered
about the p-phenylene axis and thus gain access to the anisotropic region of the two I ,3,5-substituted benzene rings,
At - 109°C the high-field shift is still marked; all signals
are broadened. Inspection of space-filling models indicates that not all of the six methyl groups of l a can be accommodated simultaneously in the interior of the molecule.
Accordingly, this provides an explanation why la, unlike
other neutral ligands, is not able to solvate inorganic salts
into lipophilic phases.
Cleavage of the methoxy groups in l a by BBr, in dichloromethane liberates the hexahydroxy compound l b
(decomp. 285OC). l b fluoresces intensely bright blue in
light of wavelength 366 nm, both in the solid state and in
solution in dimethyl sulfoxide. Alkaline solutions are
scarcely air sensitive. The FAB mass spectrum of l b in a
glycerine matrix exhibits a significant [ M + HIe peak[61.
Examination of molecular models suggests that in the
hexaanion of l b an octahedral donor geometry for metal
cations is formed; upon complexation, a helical-chiral
configuration results (Fig. 1).
By Wolfgang Kiggen and Fritz Vogtle*
We have succeeded in synthesizing a novel complex ligand-type 1, which cannot be described as a crown ether,
cryptand, or spherand. Moreover, the new ligand is a cagelike macrooligocycle which exhibits a cavity bounded on
three sides and has functional groups suitable for complex
formation“].
52
(6-n)@
H
1
co
H!/
yNJ2+cH2
oc
\
I
Fig. 1. Octahedral metal complex 01’ Ib.
0
$oRO
R:
1
o:R:CH3
H2
b : R:H
COR‘
2
”
a:R=CH,
R’= CH$
c : R = CH3
R’= CI
b : R z CH3
R‘= NaO
d :RE H
R’= H O
The colorless hexalactam l a can be synthesized by two
routes using high dilution conditions[*]via Stetter cyclization131: a) from 2,3-dimethoxyterephthaloyl d i c h l ~ r i d e [ ~ ]
and 1,3,5-benzenetriyltris(methaneamine) in 1.5% yield;
and b) from the new tris(acid chloride) 2c and 1,3,5-benzenetriyltris(methaneamine) in 13% yield (790 mg per
charge!). The hexamethoxy compound l a (decomp.
[*I Prof. Dr. F. Vogtle, Dip].-Chem. W. Kiggen
lnstitut Fiir Organische Chemie und Biochemie der Universitat
Gerhard-Domagk-Strasse 1, D-5300 Bonn 1 (FRG)
[**I
This work was supported by the Minister fur Wissenschaft und Furschung des bandes Nordrhein-Westfalen.
714
0 Verlag Chemie GmbH, D-6940 Weinheim, 1984
“Siderovhores” (iron carriers) which contain catechol’
moieties form octahedral complexes with Fe3QL71.
That l b
is a remarkably stronger complexing ligand emerges from
the observation that moist Ib attacks 1818 stainless steel,
producing a blue-black coloration. Iron and nickel powder
are dissolved in minutes, and chromium powder is dissolved within a few hours to form blue-green, green-grey,
and pink solutions, respectively, on exposure to air.
Addition of Fe3@salts to a solution of the novel ligand
l b in water at pH 11 leads to the characteristic red-violet
tint (Amax = 544 nm, E = 4680). For comparison, we prepared from 2a the colorless, open-chained, hexadentate ligand 2d, whose solution in water at p H 11-in contrast to
l b -becomes red-brown (ilmax
= 508 nm, E = 5120) upon
addition of Fe3Qsalts. Titrations of the two ligands against
Fe3@,with UV/VIS monitoring, indicate a 1 : 1 stoichiometry. Upon acidification of the Fe3@-complexsolutions of
l b and 2d, blue-black compounds precipitate out. The occurrence of a [(lig)H3Fe + HI@ peak in the FAB mass spectrum of the Fe3@complex of l b in a diethanolamine matrixr61corroborates the 1:1 stoichiometry, which suggests
the presence of one cation in the cavity, as shown in Figure
1[81
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Angcw. Chem. I n t . Ed. Engl. 23 (1984) No. 9
Extinction measurements indicate that EDTA, even
when present in 1000 fold excess (pH 1l), cannot compete
with the Fell'-complexes of l b and 2d, although the formation constant Kf for the Fe"'-EDTA complex is 102s[91.
Finally, the superiority of the ligand l b becomes clear
from competition experiments with 2d, in which ca. 70% of
the iron(ir1) ions are complexed by l b ; however, in order
to establish equilibria, the solutions require to be heated
for several hours at 100°C.
Our synthetic methodology allows construction of even
roomier cavities by using spacers larger than the two 1,3,5substituted benzene nuclei, e.g. 1,3,5-triphenylbenzene
building blocks, as we have previously employed in another connection (cyclophanes)["I. In this respect, these
macrooligocycles are also of interest for chemical reactions
in cavity interiors as well as for model studies of receptors
with larger guests['].
are predominantly formed, whereby the Au"' compounds
are reduced. Upon addition of Ph4AsC1, 1 precipitates
quantitatively from these solutions as light yellow crystalline needlesLa1.
1 forms intensely yellow solutions in dimethylformamide and dimethyl sulfoxide; columnular single crystals of 1
precipitate out from dimethyl sulfoxide when the solution
slowly takes up H 2 0 from exposure to an atmosphere of
water vapor. 1 is light sensitive and upon irradiation decomposes with a dark coloration. Decomposition also occurs at the melting point (230°C). In the mass spectrum,
only fragments of the cation can be detected. Apart from
the shoulder for v(Au-S) at 330 cm-', the IR spectrum exhibits only the characteristic bands of the cation. The Xray structure investigations were carried out at - 60°C191.
Compound 1 is isotypic with the thiocuprate(1)
I~h4p14[c~,2~xl"01.
Received: May 3, 1984;
revised: June 25, 1984 [Z 818 IE]
German version: Angew. Chem. 96 (1984) 712
[I] Cf. F. Mgtle, W. M. Miiller, ~ufurw1;ssenschQ~ten
71 (1984) 148, and literature cited therein.
[2] Cf. L. Rossa, F. Vogtle, Top. Curr. Chem. 113 (1983) 1.
131 H. Stetter, E.-E. Roos, Chem. Ber. 88 (1955) 1390.
[4] F. Dallacker, W. Korb, Justus Liebigs Ann. Chem. 694 (1966) 98.
[5] la, 'H-NMR (CD,CI,) at 27°C: 6=2.90 (s, OCH3), 4.43 (d, J - 6 Hz,
Aryl-CH2), 7.41 (s, Aryl-H, 2,4,6), 7.83 (5, Awl-H, 5,6), 7.88 (t, NH, J = 6
Hz);at - 109°C: 3.37, 4.58, 7.44, 7.79, 8.17.
[6] Prof. Dr. F. Rollgen and Dipl.-Chem. S. S. Wong, Bonn, are gratefully
thanked for recording the mass spectra and for discussions.
171 K. N. Raymond, F. L. Weitl, P. W. Durbin, J. Med. Chem. 24 (1981) 203;
K. N. Raymond, G. Miiller, B. F. Matzanke, Top. Curr. Chem. I23 (1984)
49.
(81 Elemental analyses and spectra are consistent with the synthesized compounds.
[9] 1. G. O'Brien, G. B. Cox, F. Gibson, Biochim. Biophys. Actu 237 (1971)
537.
[lo] F. Vogtle, G. Hohner, Angew. Chem. 87 (1975) 522; Angew. Chem. Int.
Ed. Engl. 14 (1975) 497; G. Hohner, F. Vbgtle, Chem. Ber. 110 (1977)
3052; S. Karhach, F. Vbgtle, ibid. 115 (1982) 427.
Synthesis and Crystal Structure of
[P~,As]~[Au,~S~],
a Distorted Cubane-Like
Thioaurate(I)**
By Gerolf Marbach and Joachim Strahle*
In aqueous solutions of polysulfides, gQld salts form
thio- or polysulfidoaurates(r); the thioaurates(1) [AuS]"
and [ A u S ~as] ~well
~ as the trisulfidoaurate(1) [AuS31e were
reported in the older literature[']. Recently, we reported the
synthesis and structure of [Ph4As][AuS9],a cyclic nonasulfidoaurate(r)[21.This species is formed from ethanolic solutions of K[Au(SCN),] and tetraphenylarsonium polysulfide. Depending on the sulfur content of the polysulfide
solution, salts of the cyclic anion [Au2Sa12' are also obtainedL3.'I. Thioaurates should be important for the chemical sensitization of photographic silver halide layers15], in
which A~[AuS]~~,']
and Ag3[AuS,]['I may occur. We have
now obtained the thioaurate(1) [Ph4Asl4[Aul2SX]
1.
The gold sulfides Au2S and Au2S3as well as tetrachloroaurates(iI1) can be dissolved in concentrated aqueous solutions of Na,S; presumably, thioaurate(1) ions [AuS2I3"
[*] Prof. Dr. J. Strahle, DipLChem. G. Marhach
[**I
lnstitut fur Anorganische Chemie der Universitat
Auf der Morgenstelle 18, D-7400Tubingen 1 (FRG)
This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie.
Angew. Chem. Int. Ed. Engl. 23 (1984) No. 9
A
Au6
Au2
Fig. 1. Structure of the thioaurate(1)
in the crystal of 1. For clarity,
the Au and S atoms are each represented by circles of the same diameter. Selected distances [pm] and angles ["I: Au-S 223.7(5)-234.6(5); Au-Au
317.9(I)-335.1(1), S-Au-S 177.8(2)- 179.4(2), Au-S-Au 86.7(2)-93.1(2).
In the crystal, the anion of 1, [Au12S8J4',adopts a distorted cubic structure whose corners and edge midpoints
are occupied by sulfur and gold atoms, respectively (Fig.
1). Gold(1) thus achieves its preferred linear coordination
with bond angles S-Au-S between 177.8 and 179.4'. The
average distance Au-S (230.6 pm) suggests a covalent single bond; the S atoms each bridge three Au atoms and enclose Au-S-Au angles of between 86.7 and 93.1'. A comparable arrangement occurs in the complex ion
[S(AUPP~,)~]@
(Au-S: 230.2-234.2 pm, Au-S-Au 82.995.0 O)[''I.
In the anion [AuI2Ssl4",the Au atoms are arranged cluster-like in the form of an almost ideal cuboctahedron. The
Au-Au distances are between 318 and 335 pm. No Au-Au
or Au-S contacts occur between the individual anions.
In contrast to 1, in the analogous thiocuprate
[Ph4P]4[C~12S8]1'01
the Cu atoms are displaced towards the
center of the cuboctahedron. Accordingly, the shorter CuCu distances give rise to a marked bending of the S-Cu-S
moiety.
Received: May 21, 1984;
supplemented: June 15, 1984 [Z 842 IE]
Germdn version: Angew. Chem. 96 (1984) 695
CAS Registry number:
I, 91742-15-3
[I] Gmelin Handbuch der Anorganischen Chemie, 8th edition, System-No.
62: Gold, Verlag Chemie, Weinheim 1954.
0 Verlag Chemie GmbH, 0-6940 Weinheim, 1984
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715
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