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Metal-Assisted Organization rather than Preorganization for the Design of Macrocyclic Hosts.

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T. M. Garrett, T. J. McMurry, M. Wais Hosseini, 2. E. Reyes, F. E. Hahn,
K. N. Raymond, J. Am. Chem. Soc. 113 (1991) 2965.
J. L. Pierre, P. Baret, G. Gellon, Angew. Chem. 103 (1991) 75; Angew.
Chem. Inr. Ed. Engl. 30 (1991) 85; A.-M. Giroud-Godquin, P. M. Maitlis,
ibid. 103 (1991) 370 and 30 (1991) 375.
I
Chem. Soe. Dalron Trans. 1988.
M. T. Ahmet, C. S . Frampton, J. Silver. .
1159.
K. Schreiber, Mitreilungsbl. Chem. Ges. DDR 37 (1990) 1577; Nachr.
Chem. Tech. Lab. 37 (1990) 1577.
R. W. Saalfrank. C.-J. Lurz, J. Hassa, D. Danion, L. Toupet, Chem. Ber.
124 (1991) 595.
All the compounds gave satisfactory analytical and spectroscopic data.
For example, 2b: deep blue crystals, m.p. 155"C.--IR(KBr): v'[cm-'] =
2215 (CN). 'H NMR (270 MHz, CD,CI,): 6 = 3.82 (s, 9 H ; 30CH3), 5.81
(s, 6H , 3CH,), 7.44 (s, 15H; Phenyl-H) (simple set of signals, broad);
',C NMR (67.7 MHz, CD,CI,): 6 = 29.38 (=C), 29.89 (OCH,), 52.39
(CH,), 128.29, 128.56, 129.29, 131.41, 133.18 (Phenyl-C or CN), 133.55
(C=N), 137.72(=C-0) (simple set of signals, broad). El-MS (70 eV): m / z
824 (M'). UVjVlS (CHJN): ?.,,,[nm] ( E ) = 604(1230), 264 (38904). 208
(50119). 3a: colorless crystals, m.p. = 154°C (decomp.). - IR (KBr):
B [cm-'1 = 2210 (CN). ' H NMR (400 MHz, CDCI,): 6 = 1.00 (s, 9 H ;
3CH,), 1.02 (s, 18H; 6CH,, [ll]), 3.72, 3.80, 3.93 (s, 3H; OCH,), 4.33,
4.55 (each 3d, 3 H ; CH-N diastereotopic); ',CNMR (100.5 MHz,
CDCI,): 6 = 27.05 (CH,), 27.09 (2CH,, [ll]), 33.56 (3C. [Ill), 51.18,
51.61. 51.65 (=C), 53.81. 54.17. 54.29 (OCH,). 57.61. 57.63. 57.68
(CH,N), 116.34(CN), 116.42(2CN, [ll]), 151.17~'151.29,
151.45 (C=N),
173.27,173.36,173.84 (=C-0). El-MS (70 eV): m / z 735 (Mt).
4a: bright
green powder m.p. > 300°C (decomp.). - IR (KBr): i. [cm"] = 2190
(CN). - El-MS (70 eV): m / z 528 ( M t ) ;FAB-MS: m / z 529 [(FeL,), + HI+,
1056 [(FeL,), + HI+, 1584 [(FeL,), + HI'.
1111 Coincidental overlap.
1121 R. T. Chakrasali, H. Ila, H. Junjappa. Synthesis 1988, 453.
[13] W. M. Reiff in I. J. Gruverman, C. W. Seidel (Eds.): Mossbauer Effect
Methodology, Yo/. 8 , Plenum, New York, London 1973, p. 89ff.
[14] H. H. Wickman, M. P. Klein, D. A. Shirley, P/7ys. Rev. 152 (1966) 52.
[15] W. R . Hagen. Biochim. Biophjs. Acra 708 (1982) 82.
[16] J.-M. Lehn, A. Rigault, Angew. Chem. tOO(1988) 1121;Angew. Chem. In[.
Ed. EngL 27 (1988) 1095; R. W. Saalfrank, A. Stark, M. Bremer, H.-U.
Hummel, ibid. 102 (1990) 292 and 29 (1990) 311; J.-M. Lehn in H.-J.
Schneider, H. Durr (Eds.): Frontiers in Supramolecular Chemisrry and
Phorochemistrj, VCH, Weinheim 1991, p. 17ff.
[17] M. Hvastijova, J. Kohout, H. Kohler, G. Ondrejovic, Z. Anorg. Allg.
Chem. 566 (1988) 111.
[18] Note added in proof This is supported bya recent X-ray structure analysis
of an analogous [CuL,] complex, which shows that the coordination
sphere of the Cu" center is a slightly distorted tetragonal bipyramid with
CN groups of neighboring systems in apical positions [19].
1191 R. W. Saalfrank, 0. Stuck, C.-J. Lurz, K. Peters, H. G . von Schnering
unpublished.
[20] We will report elsewhere about the results achieved by us with 5cyanosemicorrins [20] and Fe'+/Fe*+ ions.
[21] H. Fritschi, U. Leutenegger, K. Siegmann, A. Pfaltz, W Keller, C. Kratky,
Helv. Chim. Aria 71 (1988) 1541.
- AGO, and large differences - AAGo can occur upon hostguest complexation. This is clearly demonstrated in a vast
number of publications, in which it is shown that stability and
selectivity generally increase along the series podands, coronands, and cryptands."] Nevertheless, there are also arguments against strategies with such nicely arranged hosts :
1) the synthesis of such well-organized hosts may not be
easy; 2) once synthesized, the hosts can be modified structurally only with difficulty; 3) a host with strong binding
generally decomplexes too slowly, and the efficiency of regeneration is low.
We would like to introduce here a new concept for the
design of macrocyclic hosts and cooperative metal binding
(Scheme 1). A host with two metal binding sites is synthe-
Scheme 1. Cooperative metal binding with influence of the M2 binding site by
binding of M i .
sized in which the binding of M' to the first site influences
the second site both electronically and conformationally,
converting it from an otherwise weak binding site into a
potent site for the cooperative binding of M2. Since the final
structure formation is completed with the aid of M', the synthesis of the parent host itself becomes much easier and various structural modifications become possible by appropriate
selection of M'. Moreover, the decomplexation of M' destroys the final ligand organization and regenerates the starting host. Therefore, all of the negative aspects cited above
can be avoided. In this report, the synthesis of hosts according to the above concept and their preliminary binding characteristics will be demon~trated.[~I
The catecholate group was chosen as the unit for the M'
binding site, since it shows the highest degree of chelating
ability towards a large variety of metal ions as a result of its
ortho-dianionic form;[41a neutral polyether group was used
as unit for the coordination of alkali metal ions MZ.Accordingly, both a podand (1) and a coronand (3) were synthesized
as parent hosts (Scheme 2). We employed a benzyl group for
protecting the catechol unit.
A n n
f o o o o
fBr
Metal-Assisted Organization rather than Preorganization for the Design of Macrocyclic Hosts
By Yoshiaki Kobuke,* Yasutaka Sumida, Minoru Hayashi,
and Hisanobu Ogoshi
1 (R=H), 2 (R=Bzl)
The strategy of preorganization of macrocyclic hosts
ensures the efficient as well as selective binding of guest
molecules.['] Here, the unfavorable entropy term for assembling ligands around the guest is already overcome during
the chemical synthesis so that large changes in free enthalpy,
[*I Prof. Dr. Y.Kobuke
Department of Materials Science, Faculty of Engineering
Shizuoka University
Johoku, Hamamatsu 432 (Japan)
Y. Sumida, M. Hayashi, Prof. Dr. H. Ogoshi
Department of Synthetic Chemistry, Faculty of Engineering
Kyoto University
Yoshida, Kyoto 606 (Japan)
1496
0 VCH
Verlagsgesellschaft mbH. W-6940 Weinheim, 1991
nnn
C0
5
O
O
OH
nnn
f o o o o
3 (R=H), 4 (R=Bzl)
Scheme 2. Synthesis of 1 and 3 via 2 and 4. a) Triethylene glycol, NaH, dioxane; 60%. b) Pd/C, THF; 95%. c) Triethylene glycol (excess), NaH, dioxane;
60%. d)5, NaH, dioxane; 30%. e) PdlC, EtOH; 95%. Bzl = benzyl.
0570-0833/91/flil-1496$3.5O+.25/0
Angew. Chem. Int. Ed. Engl. 30 (1991) No. 11
The precursor molecule for podand 2 was easily obtained
by treatment of 2,3-bis(benzyloxy)benzyl bromide with triethylene glycol. In the synthesis of the coronand precursor 4,
2,3-bis(benzyloxy)-l,4-bis(bromomethyl)bnzene (5) was first
treated with an excess of triethylene glycol and the resulting
intermediate was cyclized under high dilution conditions in
dioxane with 5 to give 4. The benzy1-O bonds of the aryl
benzyl ether units were cleaved by controlled hydrogenation
over palladium/carbon (5 %) without attack at the benzyl-O
bonds of the alkyl benzyl ether units in the main chain; this
led to quantitative formation of 1 and 3.
A buffer solution (pH 8.0, phosphate) of 1 was titrated
with boric acid to give a smooth change in absorption of the
catecholate-boron complex at 290 nm. The titration curve
was consistent with formation of a 1 :1 complex and the
equilibrium constant was estimated to be 3700 90 M - ' .
An ethanolic solution of 1 was treated with four equivalents of aqueous KOH and then with one equivalent of boric
acid. A colorless precipitate was formed, whose FAB mass
spectrum gave a peak at m/z 440, corresponding to the
ternary complex of the tetranion of 1, boron, and potassium
(1 - 4 H)4- . B 3 + . K + (6). In the NMR spectrum of 6 in
CDCI, the benzyl protons give rise to an AB quartet at
6 = 4.03 and 4.96 (J = 9.6 Hz), while those in the parent
podand 1 afford a sharp singlet at 6 = 4.52. When the complexation was undertaken in the presence of NaOH, the benzyl protons in the resulting complex 7 gave an AB pattern at
slightly different 6 values (4.10 and 4.97; J = 10.0 Hz). The
differences in the chemical shifts and in the coupling constants between 6 and 7 suggest that benzyl protons are close
enough to the cationic metal center to be influenced by even
the subtle change from K + to Na'. Upon treatment of the
Na complex 7 with excess KPF,, 6 was regenerated (NMR
spectroscopic detection). These results clearly indicate that
boron is complexed with two catecholate ligands in the same
molecule leading to formation of a boron-assisted coronand,
in which two anionic oxygen atoms from the catecholate
units and four neutral oxygen atoms from the polyether
chain are nicely arranged to afford an additional metal binding site. K + or Na+ may be entrapped in this monoanionic
crown-like cavity to give the respective neutral species
(1 - 4 H ) 4 - . B 3 + . K + or(1 - 4 H ) 4 - . B 3 + . N a C . Itshould
be noted that the parent podand possesses the basic structural
units for alkali-metal binding but it is inert unless the complexation with boron organizes them into a macrocyclic
structure which still bears an anionic charge.
I t is well established that boron is generally surrounded
tetrahedrally by ligands, and that the metal-assisted coronand is presumably a C , symmetric and should be a mixture
of A and A isomers. When 0.1 molar equivalents of europium
(111) tris[3-(hydroxyl)trifluoromethylmethylene)-( +)-camphorate] was added to 6 in CDCI, the AB quartet was separated into two sets of AB quartets, one at 6 = 4.04 and 5.07
(0
0-
@
2
1: 'H NMR (90 MHz, CDCI,): 6 = 3.73 (s, 12H, OCH,CH,O), 4.70 (s, 4H,
OCH,Ar), 6.02 (s, 2H, OH), 6.45-6.95(m, 6H, C,H,), 7.81 (s. 2H, OH); MS
(FAB): mlz 394 ( M + ) ;correct C,H,O analysis.
2 : 'H NMR (90 MHz, CDCI,): 6 = 3.44-3.78 (hr. s, 12H, OCH,CH,O). 4.56
( s , 4H, OCH,Ar), 5.05 (s, 4H, PhCH,OAr), 5.13 (s, 4H, PhCH,OAr), 7.01 (m,
6H. C,H,), 7.26-7.50 (br. S, 20H. C,H,); MS (FAB): m / z 754 ( M + ) ;correct
C,H,O analysis.
3: 'H NMR (90 MHz, CDCI,): 6 = 3.72 ( s , 24H, OCH,CH,O). 4.61 (s. 8H.
OCH,Ar), 6.64 (s, 4H, C6H,), 7.13 (br. s, 4H. OH); MS (FAB): mi; 569
(M' + H), 591 ( M * Na), 607 ( M + + K).
4: 'H NMR (90MHz, CDCI,): 6 = 3.63 (s, 24H, OCH,CH,O). 4.52 (s, 8H,
OCHAr), 5.03 (s, 8H. PhCH,OAr), 7.16 (s, 4H, C6H,), 7.34 (s, 20H, C,H,);
MS (FAB): m / z 928 ( M + ) ;correct C,H,O analysis.
6 : 'H NMR (90 MHz, CDCI,): 6 = 3.37-3.77 (m, 12H. OCH,CH,O), 4.03
and 4.96 (q, 4H, / = 9.6 Hz, OCH,Ar), 6.47-6.88 (m, 6H. C,H,); UV
(CHCI,): A,,, [nm] = 290, MS (FAB): m / z 440 (Mt); correct C,H analysis.
7: 'H NMR (90 MHz, CDCI,): 6 = 3.51-3.78 (m. 12H, OCH,CH,O), 4.10
MS(FAB):
and4.97(q,4H,/ = 10.0 Hz,0CH,Ar),6.44-6.87(m,6H,C,H3):
m / z 424 (M')
8: MS (FAB): m / z 615 (M'
H), 637 (M' + Na), 653 ( M + K)
+
+
+
with J = 9.6Hz and the other at 6 = 4.09 and 5.24 with
J = 10.2 Hz. Further addition of the shift reagent gave a
larger downfield shift and a larger broadening of the latter
set of signals selectively at the lower field. This observation
is in complete agreement with the expectation. Therefore the
structures of the complexes may safely be formulated as
shown in Scheme 3.
When 3, which already has a coronand structure, was
treated with boric acid in the presence of KOH, a similar
neutral triple complex, (3 - 4H)4- . B3+ . K + (8) was obtained. The FAB mass spectrum showed a peak corresponding to (8 + H)+ together with peaks for (8 Na)' and
(8 + K)+ . The latter two ions must therefore be formed from
a quaternary complex [(3 - 4 H . B . K . MI+, with M = Na
or K. Presumably an additional monovalent metal cation
had been entrapped in the vacant coronand cavity of 8
(Scheme 4).
+
P
0
8
0-0
& \ B ( o/
O b '0
6 (M=K)
7 (M=Na)
Scheme 3. Probable structures of 6 and 7; right: drawn schematically for one
enantiomer.
Anxew. Chem. Int. Ed. Engl. 30 (1991) No. I t
6-8.
Scheme 4. Probable structure 8 ; right: drawn schematically for one enantiomer.
r?,
r-0
Table 1. ' H NMR, massspectrometric, and elemental analysis data of 1 -4and
0 VCH
In summary, the achiral parent podand or coronand was
converted upon complexation with boron into the respective
chiral coronand or a chiral bicyclic coronand with a C,-symmetry. Alkali-metal ions are bound in this newly organized monoanionic cavity. This is a successful example of
positive cooperativity for the binding of different metal ions
in a single host. It shows a clear distinction from previous
reports in which attempts at
binding showed no
erativity or if so, in negative or only marginally positive
Verlagsgesellschafi m b H , W-6940 Weinheim, 1991
0570-083319ijllll-1497 $3.50+.25/0
1497
The use of anionic ligation seems essential for
achieving positive cooperativities so that the occurrence of a
positive charge in the structure through the first metal cation
is carefully avoided.
Received: June 26, 1991 [Z 4749 IE]
German version: Angen. Chem. 103 (1991)1513
CAS Registry numbers:
1,137003-58-8:2,137003-59-9;
3.137003-60-2;4,137003-61-3:s.
137003-62-4;
6, 137003-64-6;6 (M = K'), 137003-65-7;7 (M = Na+), 137003-66-8;8
(M = K'), 137003-67-9;8 (M = Na'), 137003-68-0;
HO(CH,CH,O),H, 1122,3-bis(benzyl27-6;2,3-bis(benzyloxy)-l-(bromomethyl)benzene, 8 1464-85-9;
oxy)-l,4-bis[(2-~2-(2-hydroxyethoxy)ethoxy]ethoxy}methyl]benzene,13700363-5.
[l]a) D. J. Cram, Ange". Chem. 98 (1986)1041;Angew. Chem. Int. Ed. Engl.
25 (1986) 1039; b) D. N. Reinhoudt, P. J. Dijkstra, Pure Appl. Chem. 60
(1988)477.
[2]a) C. J. Pedersen, J. Am. Chem. Sor. 89 (1967)2495;b) J. M. Lehn, Angew.
Chem. f00 (1988)91;Angew. Chem. Inr. Ed. Engl. 27 (1988)90;c) F. Vogtle
(Ed.): Host Guest Complex Chemistry Vol. I-Ill, Springer, Berlin 1981 1984;d) R.M. Izatt, J. J. Christensen (Ed.): Synthesis of Macrocyrles, Wiley, New York 1987.
[3] Scheparrr et al. developed an idea of self-assembling ionophores and reported the complexation of two different cations in the assembly: a) A. Schepartz, J. P. McDevitt. J. Am. Chem. Soc. If1 (1989)5976.Cocomplexation of
a neutral guest and an electrophilic cation immobilized in the macrocycle
was reported by Reinhoudt et al.: b) C. J. van Staveren, D. E. Fenton, D. N.
Reinhoudt, J. van Eerden, S. Harkema, ibid. 109 (1987)3456;c) C. J. van
Staveren, J. van Eerden, F. C. J. M. van Veggel, S. Harkema, D. N. Reinhoudt, [bid. I f 0 (1988)4994.
[4]a) K.N. Raymond, T. J. MacMurry, T. M. Garrett, Pure Appl. Chem. 60
(1988)545,and references cited therein; b) P. Stutte, W Kiggen, E Vogtle,
Terrahedron 43 (1987)2065; c) J. L. Pierre, P. Baret, G. Gellon, Angew.
Chem. 103 (1991)75;Angew. Chem. Int. Ed. Engl. 30 (1991)85.
[S] a) J. Rebek, Jr., J. D. Trend, R. V. Wattley, S. J. Chakravosti, J. Am. Chem.
Sor. fO1 (1979)4333;b) J. Rebek, Jr., R. V. Wattley, ibid. 102 (1980)4853;
c) J. Rebek, Jr., R. V. Wattley, T. Costello, R. Gadwood, L. Marshall, ibid.
102 (1980)7398: d) Angew. Chem. 93 (1981)584; Angew. Chem. Int. Ed.
€ng/. 20 (1981)605;e) J. Rebek, Jr., L. Marshall, J. Am. Chem. SOC.I05
(1983)6668;f ) J. Rebek, Jr., ibid. 107 (1985) 7481; g) T. Nabeshima, T.
Inaba. N. Furukawa, Tetrahedron Lerr. 28 (1987)6211;h) F. Caviiia, S. V.
Luis, A. M. Costero, M. I. Burguete, J. Rebek, Jr.. J. Am. Chem. Sor. If0
(1988)7140.
Antiperovskite Structure with Ternary
TetrathiafulvaleniumSalts: Construction,
Distortion, and Antiferromagnetic Ordering **
By Patrick Batail,* Carine Livage, Stuart S. P . Parkin,
Claude Coulon, James D . Martin, and Enric Canadell
Our present ability to rationally design and prepare molecular solids within a predicted structure type is still in its
[*I
Dr. P. Batail, Dr. C. Livage
Laboratoire de Physique des Solides Associe au CNRS
Universite de Paris-Sud
F-91405Orsay (France)
Dr. S. S . P. Parkin
IBM Research Division, Almaden Research Center
San Jose, CA 95120 (USA)
Dr. C. Coulon
Centre de Recherche Paul Pascal, CNRS
Avenue Dr. Schweitzer, F-33600Pessac (France)
Dr. J. D. Martin, Dr. E. Canadell
Laboratoire de Chimie Theorique Associe au CNRS
Universiti de Paris-Sud
[**I This work was supported by the Ministere de la Recherche et de la Technologie (The "Ingenierie Moleculaire" Program and Research Fellowship
to C . L.), the Centre National de la Recherche Scientifique (France), and
the National Science Foundation Office of International Programs (postdoctoral fellowship for J.D.W.We thank P. Auban for her contribution to
the ESR experiments.
1498
0 VCH
Verlagsgesellschafr mbH, W-6940 Weinheim. 1991
infancy.['] Here we report that a series of ternary tetrathiafulvalenium salts of large, divalent all-inorganic hexanuclear
molybdenum halides, formulated as (TTF'+),[(Y -)(Mo,X:,)]
(X = Y = CI; X = Br, Y = C1, Br, I), has been
electrochemically assembled and shown to actually adopt a
perovskite-type[21 structure. The latter features a unique
three-dimensional arrangement of tetrathiafulvalene (TTF)
cation radicals, located at the oxygen sites of the BaTiO,
prototypical structure. Thus, a rhombohedrally distorted
antiperovskite network is identified, in which, in all four
compounds, the unpaired K-electron spins ( S = l/2) for each
of the tetrathiafulvalenium HOMOS, centered at the vertices
of vertex-sharing {Y -(TTF'+),} octahedra, undergo sharp,
long-range antiferromagnetic ordering at roughly 6- 8 K. In
fact, the initial discovery that antiferromagnetic ordering
occurs in (TTF),[(CI)(Mo,CI,,)] 1 prompted the preparation of (TTF),[(Y)(Mo,Br,,)], Y = C1 (2), Br (3), and I (4)
with the two-fold anticipation that they would form the same
antiperovskite structure and indeed order antiferromagnetically.
These observations suggest that significant molecular information can be expressed and manipulated by substitution into
a predicted target structure in order to design highly ordered,
specialized three-dimensional molecular solids. These structures act as efficient receptors for halides with unique magnetic properties, very much along the same approach that
has proven so successful in solid state inorganic chemistry. In
this respect, such a unique family of compounds bridges the
gap between organic and inorganic materials: it is indeed a
novel simple structure type recognized[31in complex molecular solids in the CSC~,[~"I
NaC1,[4b. and CdCI, structures.[4d]
It is also suggested that the three-dimensional nature of the
perovskite structure has played a role in preventing the occurrence of the spin-Peierls transition commonly 0bserved1~1
in other cation radical salts, albeit of lower dimensionality,
thereby providing a particularly simple example of geometric control of the electronic structure in the solid state. An
exchange mechanism by direct, through-space coupling of
the organic spins inside the octahedron-unprecedented in
the molecular solid state-ould
be revealed by consideration of structural and antiferromagnetic resonance data
and MO calculations.
The electrochemical assembling of the units [Mo,Cl,,]' -,
TTF", and C1- was purposely attempted in order to
demonstrate that the formation of the perovskite framework
is a consequence of the divalent character of the large cluster
anion (site A). This assumption was based on recent evidence
that (a) such associations with the monovalent, isoelectronic,
and isostructural hexarheniate cluster anions [Re,Q,C19](Q = S, Se)r6] result in the formation of 2 : l binary phases
with discrete mixed-valence [(TTF);+] d i m e r ~ ; [ and
~ l (b)
that the monovalent rhenium cluster-based, paramagnetic
perovskite previously obtained by serendipity,[61was actually a disordered material with only a fraction of the monovalent anions on the A site. Indeed, we have shown that in the
latter phase, now formulated as {(TTF'+),(TTF)}((Cl-),){(Re,Se,CI~-)(Re,Se,C1,-)) one spin fails per TTF
octahedron and no antiferromagnetic ordering occurs.[71
Black, rhombohedrally-shaped single crystals of 1-4 were
grown on a platinum wire anode upon constant low current
density (1.3 KAcm-') oxidation of TTF (0.067 mmol) in anhydrous acetonitrile in the presence of equimolecular amounts
(0.045 mmol) of the tetrabutylammonium (TBA) salts of the
hexanuclear halomolybdatersl and of the appropriate halide.
The proportions and amounts of the two anionic components in the 30 mL electrochemical cells proved to be critical
for the formation of the proper 3 : 1 :1 stoichiometry. While
OS7O-OS33~91Jll~1-f498
S 3.50+.2510
Angew. Chem. Int. Ed. Engl. 30 (1991) No. 11
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