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Cyclic Metal Complexes of Nucleobases and Other Heterocycles Molecular Boxes Rectangles and Hexagons.

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Gary, M. Meyer. New J. Chem. 1995, 19, 409; J.-C. Chambron, %-ChardonNoblat. A. Harriman, V. Heitz, J.-P. Sauvage, Pure Appl. Chem. 1993,65,2343,
N Solladie, J.-C. Chamhron, C. 0. Dietrich-Buchecker, J -P. Sauvage. Angew.
Chenz. 1996, 108, 951; Angew. Chem. In:. Ed. Engl. 1996, 35, 906.
[9] G. S . Hanan, C. R. Arana, J.-M. Lehn, D. Fenske, Angew. Chem. 1995. 107,
1191; Angew. Chem. Inr. Ed. Engl. 1995,34. 1122, G. S. Hanan, C R. Arana,
J.-M. Lehn, G . Baum, D. Fenske, Chem. Eur. J 1996,2, 1292.
[lo] H. Sleiman, P. N. W. Baxter, J.-M. Lehn, K. Rissanen, J. Clzem. SOC.Chem.
Commun. 1995,715.
Ill] P. N. W. Baxter, J.-M. Lehn, I. Fischer, M:T. Youinou, Angew. Chem. 1994,
106, 2432; Angew. Chcm. Inl. Ed. EngI. 1994,33,2284.
[12] C. 0. Dietrich-Buchecker, J.-P. Sauvage, Terruhedron 1990, 46, 503.
[I31 Crystal structure data for [I(H,0)](PF,),.3C6H,.CH,N0,, M, = 2979.346
(the crystallographically determined value for M, was 2977.24, since the positions of the H atoms of the included water molecules could not be located or
calculated), triclinic, space group PT (no. 2), a =18.239(3), b =19.766(2),
c = 20.572(2)
a = 69.53(1), B = 83.85(1), 7 = 85.22(1)i, V = 6915(2) A3,
2 = 2, pcllcd= 1.433 gcm-3, F(OO0) = 3079. T = 296+ 1 K. Crystals of 1 were
grown by slow diffusion ofbenzene into a CH,NO, solution of the complex at
293 K. Data was collected on a crystal of dimensions 0.40 x 0.40 x 0.50 mm
= 0.7107 A, graphite
(Enraf-Nonius CAD4 diffractometer, jc(MoKII)
monochromator). Of 17515 collected reflections 16 859 were unique
= 0.007), wi28-scan mode, 28 = 44” (h: 0-19.
k: -20-20,
-21 --t 2 1 ) ; 10912 reflections with I > 3u1 were used for refinement. Lp and
absorption corrections based on psi scans were applied, fl(MoKZ)
0.585 mm-’. The structure was solved by direct methods (SHELXS) [14] and
subjected to block-matrix refinement in seven blocks [15]. The H atoms were
calculated at theoretical positions (C-H 1.O 8.isotropic temperature factor
8.0 A’) and included in the final structure-factor calculations but not refined;
F,-parameter ratio = 6.09, final R value 0.055, R, = 0.064 for 1793 paramewhere w‘ is the Chebychev polynomial for F,
ters: w = d [ l . O - (AF/~CTF)~]’,
with three coefficients (12.9, -2.42, and 10.4); S E t . 1 5 , convergence, max.
shift/error 0.08. The final difference map displayed no electron density
higher than 0.77 e k ’. Crystallographic data (excluding structure factors) for
the structures reported in this paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication no. CCDC100241. Copies of the data can be obtained free of charge on application to The
Director, CCDC, 12 Union Road, Cambridge CB21E2, UK (fax: int. code
(1223)336-033; e-mail:
[14] G. M. Sheldrick in CrysrallographicComputing, Vol. 3 (Eds.: G. M. Sheldrick,
C. Kriiger, R. Goddard), Oxford University Press, Oxford, England, 1985,
p. 175.
1151 D. Watkin, J. R. Carruthers, P. W. Betteridge, CRYSTALS, Chemical Crystallography Laboratory, Oxford (UK), 1990.
[16] The deviation of the array of three Cu’ ions from linearity arises from the
curvature of 2, which in turn results from the summed effects of two types of
distortions. Firstly. when viewed perpendicular to its mean plane, the six nitrogen atoms of 2 describe a shallow arc, which stems from the fact that the
pyridazine ring is not a regular hexagon hut contracted along the N = N bond.
Secondly, the aromatic rings of 2 are bent and rotated with respect to each
other through each interring bond, which causes 2 to adopt a twisted crescent
shape when viewed along the ligand mean plane perpendicular to its long axis
(torsion angles Nl-C6-C7-N2 14.36, N3-ClO-Cll-N4 12.84, N5-C14-C15-N6
19.44”). A striking feature of the complex is the relative arrangement of the
phenanthroline moieties along 2 (Figure 1b). The three phenanthrolines from
3 are not eclipsed, but substantially staggered with respect to each other (torsional angles DI-Cul-Cu2-D2 35.56, D2-Cu2-Cu3-D3 76.90, Dl-Cuf-Cu3-D3
39.07”; D1, D2, and D3 are the centroids of the central fused C, rings in the
phenanthrolines coordinated to Cul, Cu2, and Cu3 respectively). When
viewed along the long axis of 2. one outer (coordinated to Cu3) and the inner
phenanthroline units lie on opposite sides of the mean plane through 2, whereas
the remaining outer phenanthroline sits approximately centrally Due to the
relatively short distances between the copper ions (Cul -Cu2 3.597, Cu2-Cu3
4.268, Cul-Cu3 7.753 A), the phenyl rings of the three ligands 3 cannot lie
simultaneously coplanar to 2. The relative staggering of the macrocyclic ligands about 2 is therefore a possible way of minimizing steric congestion hetween the phenyl rings. The relative displacements of 3 additionally introduce
five stabilizing face-to-face contacts between 2 and the phenyl rings of 3, and
a further two face-to-face and three edge-to-face interactions (that is, within
3 4 A) between the phenyl rings themselves. The highly dissymmetric environment of 3 is however not observed in the ‘H NMR sprectrum of 1, presumably
because of averaging by rapid rotational oscillations at room temperature. The
wide range of N(ligand 2)-Cu-N(ligand 3) bond angles (108.1(2)-134.9(2)”)
indicates that the Cut ions are located in a highly distorted tetrahedral coordination polyhedron, and results mainly from the staggering of ligands 3 along
2. On the other hand, the Cu-N bond lengths (1.973(4)-2 169(4) are unexceptional. A single water molecule is captured within the cation and hydrogen
bonded to three of the oxygen atoms of the central macrocyclic ligand 3,
(O(H,O)-O(3) 2.95-3.06 A).
117) Attempted further purification by column chromatography on silica gel or
alumina with a variety of eluant systems resulted in rapid dethreading and
extensive decomposition of 1(PF6),
i~oVCH Verlugsgesellschaft mhH. 0.69451
Cyclic Metal Complexes of
Nucleobases and Other Heterocycles:
Molecular Boxes, Rectangles, and Hexagons**
Holger Rauter, Ilpo Mutikainen,* Merja Blomberg,
Colin J. L. Lock, Pilar Amo-Ochoa, Eva Freisinger,
Lucio Randaccio,* Ennio Zangrando,
Elisabetta Chiarparin, and Bernhard Lippert*
In memory of Colin J. L. Lock
Spontaneous self-assembly of cyclic metal complexes with
right angles at their corners (“molecular squares”, “molecular
boxes”) represents an area of great current interest.” -41 In general, the metal unit provides the right-angular component,
whereas four bifunctional organic ligands, for example 4,4bipyridine, form the sides (Scheme la) .[’I In principle, it is possible to reverse this situation by placing the organic ligands at
the corners and the metal units along the edges.[6. This leads
to “squares” in the strict sense (Scheme 1b) .[*I Use of six-membered heterocycles with angles of 120” at the ligands and linear
metal units provides molecular hexagons instead of squares.
Scheme 1. Schematic representation of the basic structural types of molecular
Variations of this principle with simultaneous use of different
metal moities (such as cis-MX, and trans-MX, with M = Pt“,
Pd”; X = NH,, H,O, NO;, etc.) are also feasible (Scheme lc).
Here we report on relevant principles of this strategy utilizing
the two nucleobases uracil (U) and I-methylcytosine (1-MeC) as
well as 2-aminopyridine (Hampy ; Scheme 2).
We recently described a “molecular box” (open at the top and
bottom) consisting of four Pt”(en) units (en = 1,2-diaminoethane) and four bridging uracil nucle~bases.[~~
The cation 1
(UH = monoanion from uracil) resembles calix[4]arenes as
Dr. 1. Mutikainen
Department of Chemistry
University of Helsinki
SF-00100 Helsinki (Finland)
Prof. Dr. L. Randaccio, Dr. E. Zangrando, Dr. E. Chiarparin
Dipartimento di Scienze Chimiche
Universita di Trieste
1-34127 Trieste (Italy)
Fax: Int. code +(40)676-3903
Prof. Dr. B. Lippert, Dr. H. Rauter, Dr. P. Amo-Ochoa,
Dip].-Chem. E. Freisinger
Fachbereich Chemie der Universitat
D-44221 Dortmund (Germany)
Fax: Int. code +(231)755-3797
Dr. M. Blomberg
Department of Physics, University of Helsinki
This work is in memory of Prof. Dr. C. J. L. Lock (Laboratories of Inorganic
Medicine, Chemistry and Pathology, McMaster University, Hamilton, Ontario L8S4M1, Canada) who contributed to it but passed away too early. We
gratefully acknowledge financial support of the Deutsche Forschungsgemeinschaft, the Fonds der Chemischen Industrie, and MURST and CNR (Rome,
Italy). We thank Prof. Dr. W. S . Sheldrick and Mrs H. Mayer-Figge (Bochum,
Germany) for their help with the structure determination of Pt,Hg,. This
research was a part of HCM and COST projects.
Angew. Chem. Int Ed. Eng:. 19F7,36.No. 12
1 -Methylcytosin
Scheme 2. The ligands uracil. 1-methylcytosine, and 2-aminopyridine.
far as its structure and solution dynamics are concerned. This
analogy also includes the propensity of calix[4]arenes to complex metals."0. "1 For example, after deprotonation of U to the
uracil dianion (UH-,), 1 binds additional divalent cations to
yield octanuclear complexes 2 (M = cis-Pt"(NH,), (2a), Pt"(en)
(2b). Ni"(H,O), (2c), Pd"(en) (Zd), Cu" (2e)). With M = Ag'
[{Pt(en)(UH- ,-Nf,N3))4]4+ 1
[{Pt(en)Ag(UH-1)}4]*+(2f) is obtained. In all of the octanuclear compounds the basic structure of the open box 1 is retained,
but, instead of a single Ptii(en)residue, two metal units (Pt"(en)
and M) represent the corners of the boxes (Scheme 3).
3.036(2) A. Therefore, the shortest Pt-Pt separation is about
0.1 A longer than that in related dinuclear complexes cis[Pt(a),L,Pt(a),]'
(a = NH,; head-to-head orientation of
bridging uracil nucleobases L) .I1 The dihedral angle between
the planes of the Pt(en) and cis-Pt(NH,), moities (Pt(1) and
Pt(2)) is also rather large (40.9(6)"). Uracil rings at opposite
sides of the box are not exactly parallel, which leads to different
O(2)-O(2c) and C(5)-C(Sc) distances (5.92 and 4.27 A, respectively). Considering the spatial requirements of the 71 electron
clouds of the uracil rings, the openings of the box at the top and
bottom, which are rotated by 90" with respect to each other,
are about 1 x 2.5 A. There are no significant intermolecular
Pt . . . Pt contacts, as frequently seen for dinuclear cis[Pt"(a),L,Pt"(a),]'+ cations (L = UH - or cyclic amidate).[',
The composition of 2 b (M = Pti1(en))i'2h1is analogous to
that of 2a. Within the Pt, pairs, metal-metal separations differ
slightly: 2.998(2) and 3.023(3) A. The cations of the Pt,Ni, compound 2 ~ " ' "is~ also of similar composition, but the NI" centers
display distorted octahedral coordination spheres of five oxygen
atoms (0(4), 0(2), and three OH, groups) and a Pt atom. All
four Pt-Ni distances within 2c vary slightly (2.652(2)2.700(5) A). The structure of the Pt,Ag, complex 2f proves that
the cone conformation can also be stabilized by metal ions and
demonstrates that the 1,3-a/ternate cone rearrangement can
take place even in strongly acidic medium with the help of a
suitable metal ion. Considering the close structural similarities
of related di- and trinuclear PtM and Pt,M complexes
(M = Pt", Pd", Cu") with uracil nucleobases,f'51we propose
that the compositions of the Pt,Pd, and Pt,Cu, cations 2d and
2 e are analogous to those of 2a-2c.
Cations 2 a and 2b are inert in D,O (see Experimental Section) and only decompose at pH* = 0. In the presence of excess
NaC1, loss of the Pt units bound to O(4) and O(2) takes place
over a period of several days at 40 'C. The cations react with
excess CN- within minutes to give 1 and [Pt(CN),I2-. In a slow
secondary reaction (1 d, 22 "C) an equilibration of 1,3-a/ternate
and cone forms of 1 occurs (see Experimental Section). These
findings confirm earlier observations that, despite the high thermodynamic stability of [Pt(CN),]'-, N(3)-platinated uracil
(and thymine) is inert with respect to CN-."'] Only those Pt
residues bound to the exocyclic oxygens are readily displaced.
The reaction 1 4 M"+ + 2 can, therefore, be reversed; this fur+
A e h
[{Pt (en)(UH-2)M}4I8' 2a - 2e
Scheme 3. Schematic representation of the molecular boxes 1 and 2.
The complex cations were isolated as their nitrate salts, and
crystals suitable for X-ray crystallography were obtained for
2a-2c and 2f. Although the octanuclear composition of the
cation was established in all cases, a complete crystallographic
analysis was only possible for 2a.[""] For 2bJ12bl2 ~ , [ ' ~and
disorder of the NO; anions and water molecules was so
severe that, despite repeated attempts and data collection at low
temperature, no satisfactory refinement was achieved.'' 2b3c1
The structure of the cation in 2 a is depicted in Figure 1. The
basic feature of 1, the 1,3-a/ternate arrangement of the four
uracil nucleobases, is evident. The acidic protons of the UHligands in 1, located between the O(2) and O(4) atoms of adjacent nucleobases, have been replaced with cis-Pt"(NH,), units
in 2a. As a consequence, each uracil ring carries a metal ion at
four positions (N(I), N(3), 0(2), O(4)). Compared to the free
base['31 and platinum complexes coordinated at N(l) and
there are no significant changes in the ring geometry.
The Pt(l)(en) units, which link the N(l) and N(3) positions,
display normal geometries, as do the cis-Pt"(NH,), moities. The
Pt-Pt distances are Pt(1)-Pt(1c) 8.31, Pt(l)-Pt(2a) 7.51,
Pt(1)-Pt(1 b) 5.88, Pt(l)-Pt(2b) 4.75, and Pt(1)-Pt(2)
Anguu,. Chrm J I I I . Ed. Engl 1997. 36, No. I 2
Verlugsgesellschujt mbH, 0.69451 Weinheim,I997
0570-0833197;3612-1297$17.j O i .jO'0
ther corroborates the analogy with the metal-coordinating
properties of suitably modified calix[4]arenes.
The crystal structure determinations of 2a and of its precursor 1 demonstrate that, irrespective of the 120" angle between
the Pt-N1 and Pt-N3 vectors, molecular boxes are formed as
long as the metal units are of czs geometry. As shown for 6
[IPt(CH,NH,),(I-MeCH-,),Hg,(OH)},ltNO,),.4H,O 6
(1 -MeCH - = dianion of 1-MeC) trans geometry at the metal
units leads to formation of a molecular hexagon (Scheme 4).
To suppress formation of open-chain oligomers, fixation of the
two cytosine nucleobases in 3['*,191 in a head-to-head arrangement is advantageous. This can be accomplished by metal binding at the deprotonated exocyclic aminogroupsr'81by, among
others, Hg".r191
Electrophilic attack of excess Hg(NO,), or Hg(OAc), at the
C5 positions of the two cytosine ligands in 4 leads, presumably
via 5, to 6 (Scheme 4). Metalation reactions at C5 are known for
Figure 2 View of thecation [{Pt(CH3NH,),(C,H,N,0)2Hg3(OH)(N0,)J,141
Selected bond lengths [A] and angles I"]: Pt-N(3) 2.05(2), Pt-N(3') 2.07(2),
Hg(4)-N(4) 2.08(2), Hg(4)-N(4) 2.08(2), C(5)-Hg(5) 2.05(2), Hg(5)-O(5)
2.09(1). C(5')-Hg(5') 2.04(2), Hg(5')-0(5') 2.06(1); N(3)-Pt-N(3') 172.8(5), N(4)Hg(4)-N(4') 162.3(6), C(5)-Hg(5)-0(5) 175.0(6). For intermetallic distances see
Figure 3.
Figure 3. Dimensions and intermetallic distances in the cation of 6.
Scheme 4. Synthesis of 6.
free cytosine[201and various uracil derivatives!211 Following the
formation of 6 by 'H NMR spectroscopy indicates that reaction
of the head-to-head rotamer[221of 3 via an intermediate (5?)
takes place with a drop in pH. Compound 6 was isolated from
acidic solutions (pH = 1.8-3) and characterized by elemental
analysis, X-ray crystal structure d e t e r m i n a t i ~ n , ' and
~ ~ ] NMR
Figure 2 shows the structure and Figure 3 schematic views
of the cyclic cation [{Pt(CH,NH2),(C,H,N30)2Hg,(OH)of 6. The basic form of the centrosymmetric cation
is that of a compressed hexagon (sides 7 and 5.5 A) with four
Hg" and two Pt" atoms at the edges, and four nucleobases and
two OH groups representing the corners. Two additional Hg"
0 VCH Verlugsgesellschufi mbH, 0.69451
ions, which bridge pairs of deprotonated exocyclic N(4) groups
of the cytosine bases, are located along the Pt-Pt vector. All
metal ions and OH groups are almost coplanar. The cation of 6
is made up of two units of4, which are linked by two Hg-OH-Hg
units. Apart from the Pt-Hg(4) distances (2.727(1)A in 6,
2.785(1) A in 4) and the additional Hg(5) ions, there are no
major differences between the structures of 4 and 6. Even the
NO; groups bridging the dinuclear PtHg units in 6 are present.
In the crystal Pt,Hg, cations form infinite, interlacing staircases. Thus the four O(2) oxygen atoms of the cytosine bases
each form pairs of two hydrogen bonds with the amino protons
of the CH3NH2 groups of the adjacent cations (0-N 2.85(2)
and 2.89(2) A). The intermolecular separation between the Pt
ions is 4.929(2) A. The steps in the second direction are formed
by two intermolecular OH. . . OH hydrogen bonds (O(5)-O(5)'
2.773(23) A) and four weak intermolecular Hg-ONO, bonds
between the bridging nitrate groups and the Hg(5) or Hg(5')
center of the adjacent cations (Hg-0 2.68(2)-2.94(2) A). The
Hg ions located at the sides of the hexagon exhibit different
coordination geometries.
0570-0833/97/3612-1298$ 1 7 . S O i .SO10
Angew. Chem. Int. Ed. Engl. 1997, 36, No. I 2
A special structural feature of 6 is the arrangement of the six Hg" ions
(Figure 4). It is feasible
that in solution, as in the
solid state with weakly
bonded nitrate anions and
water molecules, interactions between the Lewis
acidic Hg centers and nucleophiles occur, which
could lead to specific substrate binding and catalyFigure 4 Space-filling model of the
sis.[26,271 This arrangecation in 6 , bridging NO; groups have
ment bears some resembeen omitted
blance to the surface of a
Reaction of Hampy with first trans-[Pt"(CH3NH,),(H,0),1(NO,), and then [PdC1,l2-/AgNO, leads to a species that can
be considered as a hybrid between a rectangle and an open box
containing both trans-MX, and cis-MX, units. Complex 9 was
obtained from 7 upon reaction with K,[PdC1,] and excess
AgNO,. Initially 7 reacts with K,PdCI, with a drop in pH to
give a poorly soluble orange product (S), which redissolves with
red coloring upon addition of AgNO,. Dark red cubes of 9
crystallize from the solution. X-ray structure a n a l y s i ~ [reveals
that 9 consists of two crystallographically independent hexanuclear cations (A and B), nitrate anions, and water of crystallization. The two cations have a crystallographic C, axis, which
passes through the two Pt centers in the case of A and is perpendicular to the Pt-Pt vector in B. Consequently, adjacent cations
are mutually perpendicular in the crystal lattice. Cation A is
depicted in Figure 5. Each trans-[Pt(CH,NH,),] unit carries two
coplanar aminopyridonate rings that are bound to Pt through
the endocyclic ring N atoms and adopt, unlike in 7, a head-tohead orientation. The two Pd, units each bridge the four deprotonated exocyclic amide nitrogen atoms to give a p3-qzcoordination pattern for the ampy ligand~.[~*]
All four Pd ions have cis
geometries: the four remaining coordination sites are occupied
by oxygen atoms (three from NO; and one from H,O). The
resulting Pd,N, rings are folded along the N-N vectors, which
leads to short Pd-Pd distances (2.877(2) and 2.855(2) A). In
planar Pd,N, rings, metal-metal distances are usually much
The edges of the two cations are 4.07
longer (3.0633(9) A).1321
(NI . . . NI') by 7.18 (NI . . N4) (A) and 7.23 A (B), respectively. Pt . . .Pt distances are 6.949(1) (A) and 6.990(1) A (B), and
the separations between the midpoints between the pairs of oppositely placed Pd, units are 6.276(1) (A) and 6.270(1) A (B). In
both cations the two Pt(ampy), units are slightly twisted (Figure 6). The roughly coplanar orientation of the four NH protons of the exocyclic amide groups could be of interest with
respect to receptor properties.
Figure 6. Side view of cation A in 9. The two Pt(ampy), units are slightly twisted
with respect to each other
Experimental Section
2: In a typical experiment, 1 (0.058 mmol) was dissolved in 15 mL
of an aqueous solution of the respective me~alsalt (Ni(NO,),,
Cu(NO,),, AgNO,, c~$-[M(a)~(H,0),]~'
with M = Pt", Pd";
four- to tenfold excess). The solution was concentrated under
vacuum to about 5 mL and then exposed to air. The pH values of
the solutions were typically between 1 . 5 and 2.5. In the case of the
Ag compound Z f the pH was adjusted to 0 with HNO,. Within
2 - 7 d yellow (Za, 2b, Ze), green/yellow ( t c ) , orange (Zd), or
colorless (2f) crystals formed, which were isolated by filtration,
washed with a minimum amount ofwater, and dried in air. Yields
15-30%. Higher yields were not possible since further concentration resulted in cocrystallization of the metal-salt reagent. Satisfactory elemental analyses (C. H, N) were obtained for
~ ( ~ z ~ R ~ 2 ) ~ ( ~ ~ 3 ~ R ~ t , ( ~ ~ (W.
~ ~ ~ ~ ~ z ~ ~ l (
[ ( C Z H R N ~ ) ~ P ~ R ( C ~ H ~ N ~ O , ) , J ( N O(Zb),
1 5 H,O ( 2 ~ ) ~
( 2 e ) . and
[(C,HsN,),Pt,(C,H,N,O,),Ag,l(NO,)s(HzO), (2f).
2a: ' H N M R (200 MHz, D,O, TSP, pH* =1.5-7)- 6 = 8.01 (d,
J = 7 . 4 H z , H 6 ) , 590(d.H5).2.8(en)
Figure 5. Structure of the crystallographically independent cation A in 9. Selected bond lengths [A]
and angles [ 1. Ptl-Nl 2.04(1), Pt2-N4 2.01(2), Pdl-N2 2.03(2), Pdl-N5 2.03(1), Pd2-N2
2.07(1). Pd2-N5 2.08(1); N1-Ptl-Nl' 172.0(6). N4-Pt2-N4 175.1(7). Pdl-N2-Pd2 89.2(6). Pdl-N5Pd2, 88.9(6). N2-PdI-NS 77.4(6), N2-Pd2-N5 75.4(5).
Angm,. C'hmn. Inr. Ed. Engl 1997, 36. No 12
2b: ' H N M R (200 MHz, D,O, TSP, pH" =1.5-7): 6 =7.95 (d.
J = 7 . 4 H z , H6), 5.87 (d, H5), 2.7 (en). IYSPt NMR (D,O,
pD = 4): 6 = - 2484 (PtN,), -1570 (Pt20,); immediately after
addition of CN- (20 equiv per Pt atom, pD = 12): 6 = - 2613 ( I ,
PtN,, 1,3-ulternure), -4720 ([Pt(CN),j*-); after 6-18 h:
6 = - 2613 (1, PtN,. 1.3-ulternure). --2647 (1, PtN,, cone),
-4720 ([Pt(CN)J-). Assignment ofthe conformers of 1 bycomparison of 195Ptand 'H NMR spectra [9a] of 1 in the presence of
CN- (pD = 8.2)
Verlugsgesellschufr mhH, D-69451 Wernheim. 1997
OS70-0833/97/3612-r299S 17 .iO+ .50:0
6: Method 1 . Hg(NO,), (324 mg, 0.95 mmol) was added to a solution of trans[Pt(CH3NH2),(1-MeC),](NO,), (3) I181 (200 mg, 0.32 mmo1)in water (13 mL), and
the solution stirred at 22'C. After 7 h a colorless precipitate was isolated by filtration, washed with a minimum amount of H,O and MeOH, and dried in the air.
Colorless crystals of 6 form in the filtrate (pH = 2-2.5) within 3 d. The precipitate
and the single crystals are identical (IR and 'H NMR spectroscopy). Yield 223 mg
(51 YO).Method 2: Hg(NO,), (53 mg, 0.15 mmol) was added to a solution of trans[Pt(CH3NH,),(1-MeC.,),Hg](NO,),(4)
[19](64 mg,O 07 mmol)inwater(l3 mL),
and the solution stirred at 22 "C. Precipitation of 6 started after 4 h. The yield of the
isolated product after 19 h is 18% and increases to that of Method 1 with higher
concentrations (NMR). Elemental analysis data (C, H, N) agree with the composition determined by X-ray analysis. ' HNMR (200 MHz, D,O , NMef internal
standard, TSP) 6 =7.25 (s. H(6); 199Hgsatellites: ' J = 196 Hz). 7.47, 7.56, 7.61
(three weak singlets; intensities increase with time and after addition of DNO,
(pD = 1.7) at the expense of the signal at 6 =7.25). 195PtNMR (D,O , [PtCl,]'-):
6 = - 2195.
7: Reaction of truns-[Pt(CH,NH,),C12] with Hampy (2 equiv) in the presence of
AgNO, (2equiv) in H,O (pH =7, 1 d, S O T ) , removal of AgCl and little Pto by
filtration, and crystallization results in colorless cubes of 7 in 84% yield Satisfactory elemental analysis (C, H, N). '95Pt NMR (42.95 MHz, [PtCI,]*-): 6 = - 2681;
'HNMR (200MHz, D,O, pD =7. TSP): 6 = 8.40 (m, H6; "'Pt satellites:
3Jz34 Hz), 7.66 (m, H4), 6.82 (m. H5, H3), 2.14 (s, CH,: '95Pt satellites:
,J=43 Hz). Derivative 7' was prepared analogously with AgC10, instead of
AgNO,. IR (KBr, cm-I): = 3500 s, 3380 s, 3260, 3220, 3160 8 , 1680 s, 1650 s,
1615s, 1555 s, 1500 s,138Ovs, 1310m, 1220m, 1140m, 1060m,810s,650m,565 s,
510 m, 480 m. Crystal structure analyses of 7 and 7' confirmed the compositions.
8: Compound 7 (0.5 mmol) was dissolved in H,O (20 mL), and the pH value of the
solution (6.3) adjusted to 12.2 with NaOH. K,[PdCI,] (1 mmol) dissolved in water
(5 mL) was added dropwise with stirring. Precipitation of red-orange 8 started
immediately. The pH value of the solution, which dropped to 4, was repeatedly
adjusted to 7 until it remained constant. After the solution had been stirred for 1 h
at 22'C, the precipitate was isolated by filtration, washed with water, and dried
at 40°C. Elemental analysis (C, H, N, Cl) approximately corresponded to
Yield 90%. 1R (KBr, cm-I).
i = 3530s,b,3280s,1680~,1660s,1610s,1520s,1490s,1330m,1230m,1250m.
1150 m, 1140 m, 820 m, 500 m, 360 m, b.
9: Excess AgNO, (8-IOequiv) was added in small portions to a suspension of 8
(0.133 mmol) in H,O ( 5 mL) until 8 had completely dissolved. The now dark red
solution was filtered to remove AgCl and concentrated at 22 ' C Within two weeks,
dark red cubes of 9 formed. Only the first fraction (10- 15% yield) was not contaminated with AgNO, and other products. Elemental analysis (C, H, N) of a freshly
isolated sample was in agreement with a septa- or octahydrate (Pt-Pd = 1 :2 (scanning electron microscopy)). The X-ray structure analysis indicated six positions for
water molecules, five of which display occupancies of only 0.5 '"Pt NMR (D,O):
6 = - 2594; 'HNMR (D,O, pD = 3 7). 6 = 9.09 (d, I H ) , 9.02 (d, l H ) , 8.20 (t,
1 H). 7.53 (t, 1 H), 2.02 (s, 3H). The signals for the aromatic protons could not be
unambiguous assigned, even with a 'H- ' H COSY experiment; coupling constants
were determined from the 2-D, J-resolved NMR spectrum (3J-6-7, 4J-1.31.4 Hz); IR (KBr, cm-'1: i = 3500s, vb, 3160 s, 1615 s, sp, 1565 s, sp, 1480 vs,
1440vs. 1 3 8 0 ~ s .1270vs, 1245s, 1200s, 1160m, 1100. 1090m, 1OOOs.b. 850m,
825m, sp, 790m; UV/Vis (H,O): i.[nm] (&[molL-'cm-']) = 218 (43790),
275 (sh), 300 (32720), 380 (6106), 437 (7514).
Received: November 7, 1996 [Z9740, 29741, Z9740IEl
German version: Angew. Chem. 1997, 109. 1353-1357
Keywords: macrocycles * nanostructures
platinum - supramolecular chemistry
[l] Reviews: D. Philp, J. F. Stoddart, Angew. Chem. 1996, 108. 1243; Angew.
Chem. I n / . Ed. Engl. 1996,35, 1154, C. A. Hunter, ibid. 1995, 107, 1181 and
1995.34, 1079.
[2] M. Fujita, J. Yazaki, K. Ogura, J Am. Chem. SOC.1990,112,5645, Chem. L p t t .
1991, 1031.
[3] P. J. Stang, D. H.Cao, J A m . Chem. Sue 1994, 116,4981; P. J. Stang, D. H.
Cao, S. Saito, A. M. Arif, ibid 1995,117,6273; P. J. Stang, B. Olenyuk, Angeiv.
Chenz. 1996, 108, 798; Angew. Chem. I n t . Ed. Engl. 1996,3S, 732.
[4] Additional examples: R. W. Saalfrank, 0. Struck, D Danion, J. Hassa, L.
Toupet, Materials 1994, 6, 1432; W. S. Sheldrick, H. S. Hagen-Eckhard, S.
Heeb. Inorg. Chim. Actu 1993, 206, 15; X. Chi. A. J. Guerin. R. A. Haycock,
C. A. Hunter, L. D. Sarson, J. Chenz. Sue. Chem. Conznzun. 1995, 2567, M.
Ohba, H. Okawa, T. Ito, A. Ohto, ihid. 1995, 1545; T. Kajiwara. T. Ito, ihid.
1994, 1773; P. Chaudhuri, I. Karpenstein, M. Winter, M. Lengen. C. Butziaff.
E. Bill, A. X. Trautwein, U. Florke, H.-J. Haupt, Inurg. Chem. 1993, 32, 888.
151 The term "molecular square" [3] is somewhat misleading in that it ignores the
three-dimensional structure (with the organic ligand perpendicular to the plane
created by the metal ions). Therefore, the term "open box" is better.
[61 A. Schreiber, E. C. Hillgeris, B. Lippert, 2. Nururforsch. 5 1993, 48, 1603.
[71 C. M. Drain, J:M. Lehn, J Chem. Suc. Chem. Cummun. 1994.2313; ihid. 1995,
0 VCH Veriugsgeselischuft mbH, 0-69451 Weinheim. 1997
Coplanar arrangement of the organic ligand and metal center.
a) H. Rauter, E. C. Hillgeris, A. Erxleben, B. Lippert, J. Am. Chem. Sue. 1994,
116,616; b) H. Rauter, E. C. Hillgeris, B. Lippert, J Chem. Soc. Chem. Cummun. 1992, 1385.
Review: V. Bohmer, Angew. Chern 1995,107,785, Angew. Chenz Int. Ed. Engi.
1995, 34, 713.
Other examples of multiply metalated species: W. Xu, J. P. Rourke, J. J. Vittal,
R. J. Puddephatt, Inorg. Chem. 1995,34, 329; X. Delaigne, J. McB. Harrowfield. M W. Hosseini, A. De Cian, J. Fischer, N. Kyritsakas, J. Chem. Sue
Chem. Cummun. 1994, 1579; E. Solari, W Lesueur, A. Klose, K Schenk, C.
Floriani, A. Chiesi-Villa, C. Rizzoli, Chem. Cummun. 1996, 807.
( M , = 2945.86); tetragoCrystal structure analyses: a) 2a: C,,H,,N,,O,,Pt,
nal, space group 14,ja (no. 88), u = h = 28.356(5), c = 8.630(5) A, V =
6939(4) A', 2 = 4, pcalcd
= 2 82 g ~ m - F(O00)
~ ; = 5408; 2168 observed reflections with 1>2o(I); R1 = 0.0698; Rigaku ACF-7S diffractometer, Mo,,
radiation ( 2 = 0.71069 A), T = 193 K;the structure was refined with full-mamix, least-squares methods [30]. b) Zb: monoclinic, space group C2/c,
u = 33.728(7), h = 8.941(2), c = 30.140(6) A, B = 125.90(3)", V =7363(3) A3,
2 = 4. c) 2c: monoclinic, space group f2(l)/n, a = 8.578(5), h = 24.278(10),
c = 32.186(12)A, 4, = 92.24(4)'. V = 6698(5) .A3, 2 = 4.
R. F. Stewart, L H Jensen, Actu Crystullugr 1967,23,1102; G. S. Parry, hid.
1954, 7 , 313.
R. Faggiani, B. Lippert, C J. L. Lock, Inorg. Chem. 1980, 19, 295.
B. Lippert. f r o g . Inurg. Chem. 1989, 37, 1 ; E, Zangrando, F. Pichierri, L.
Randaccio. B. Lippert, Cuurd. Chem Rev. 1996, 156, 275.
H. Schollhorn, U. Thewalt, B. Lippert, Znurg. Chim. Actu 1984, 93, 19, and
references therein; L. S. Hollis, S. J. Lippard, Inorg Chem. 1983,22,2600; J.-P.
Laurent, P. Lepage, F. Dahan, J Am. Chem. SUC.1982, 104, 7335.
G. Raudaschl-Sieber, B. Lippert, Inorg. Chem. 1985,24,2426: G. Frommer, B.
Lippert, hid. 1990, 29, 3259; M. Schmulling, B. Lippert, R van Eldik, ibid.
1994. 33, 3276.
M. Krumm, E. Zangrando, L Randaccio, S. Menzer, B. Lippert, Inurg. Chem.
1993, 32, 700; D. Holthenrich, M. Krumm, E. Zangrando, F. Pichierri, L.
Randaccio, B. Lippert, J. Chem. SUC.Duiton Trans. 1995,3275; G. Fusch, E. C.
Fusch, A. Erxleben. J. Huttermann, H. J. Scholl, B. Lippert, Inorg. Chinz. Act0
1996, 252, 167.
M Krumm, E. Zangrando, L. Randaccio, S. Menzer, A. Danzmann, D.
Holthenrich, B. Lippert, Inurg. Chem. 1993, 32, 2183.
R. M. K. Dale, E. Martin, D. C Livingston, D. C. Ward, Blochemisfry 1995,
14, 2447.
P. H TOmd, I. M. Dalla Riva Toma, D. E. Bergstrom, Acta Crystuilugr Sect.
C 1993,49,2047; M. Hopp, A. Erxleben, I. Rombeck, B. Lippert, Inurg. Chem.
1996,35, 397; F. Zamora, M. Sabat, B. Lippert, ibid. 1996, 35, 4858.
D. Holthenrich, 1. Sovigo, G. Fusch, A. Erxleben, E. C. Fusch, 1. Rombeck.
2. Nuturfursch. B 1995, 50, 1767.
B. Lippert,
[23] Crystal structure analysis of 6: SiemensP4 four-circle diffractometer, Mo,
radiation, room temperature, [C,,H,,N,,O,,PtHg, .2H,0],. M , = 2688.58,
triclinic. space group Pi, u =7.712(2), b =13.369(3), c =13.749(3)A,
3 = 84.02(3),
=78.77(3), y = 83.65(3)', V = 1376.9(6)A3, 2 =1, pCalid=
F(O00) =1208, ~ ( M o , , ) = 21.821 mm-I, w-scan with
3.242 gcm-',
4 1 20<42.5", absorption correction: 9-scan/DIFABS, of 3320 reflections
measured 3034 were independent, and 2253 observed (F,24a(F,)), max./min.
residual electron density = 1.20 and - 1.21 e A - 3 , R, = 0.0435 and wRI =
0.0965 (observed reflections), R , = 0 0647 and wR2 = 0.1095 (all reflections).
The structure was solved with Patterson and Fourier methods (SHELXS86) [24] and refined with least-squares methods (SHELXL-93) [25].Anisotropic temperature factors were used for all non-hydrogen atoms except disordered
nitrate oxygen atoms (061, 061A. 063, 063A). The dimer is on a crystallographic inversion center. and two anions and two water molecules are independent. Two nitrate oxygens are disordered with occupancies of 0.25 and 0.75
(061, 061A) and 0.8 (063, 063A) [30].
[24] G. M. Sheldrick, SHELXS-86, Universitat Gottingen, 1990.
1251 G. M. Sheldrick, SHELXS-93, Universitit Gottingen, 1993.
[26] The fact that 3-(trimethyIsilyl)-l-propanesulfonate(TSP) cannot be used as a
'H NMR standard is possibly due to such an interaction
[27] Multidentate Lewis acids: Z Zheng, C. B. Knobler, M. F. Hawthorne, J Am.
Chem. Sue. 1995, 117, 5105; X. Yang. C. B. Knobler, Z. Zheng, M. F.
Hawthorne, ihid. 1994, 116, 7142; M. Simard, J. Vaugeois, J. D. Wuest, ihid.
1993, If5. 370; X. Yang, S. E. Johnson. S. I. Khan, M. F Hawthorne, Angew.
Chem. 1992, 104,886; Angea.. Chem. I n [ . Ed. Engi. 1992,31,893.
[28] R. G Raptis, J P. Fackler, Jr., Inurg. Chem. 1988, 27, 4179.
[29] Crystal structureanalysis of9: C,,H,,N,,0,,Pd,Pt,~3.5H20 ( M . = 1907.57);
monoclinic, space group C2/c; u = 21 722(2), h = 22.013(5). c = 23.909(4) A,
B = 100.576(91", V =11238(7) A', 2 = 4, psll.d = 2.25 gem-,; R = 0.052,
R,. = 0.061 [for 4571 reflections with I>3u(I)]; Enraf-Nonius-CAD4 diffractometer, Mo,, radiation ( . = 0.71069 A), graphite monochromator. The
structure was solved by a combination of direct methods and Fourier techniques and refined with full matrix. least-squares methods. The metal ions were
anisotropically refined, and contributions of H atoms were included at calculated positions in the refinement (except of H,O molecules); Pd, units in cation
A are disordered (0 85 : 0.15)[30].
0570-0833i97/3612-1300$ 17.S0+ .50j0
Angew. Chem. I n i . Ed. Engl. 1997, 36. Nu. I2
[30] Crystallographic data (excluding structure factors) for the structures reported
in this paper have been deposited with the Cambridge Crystallographic Data
Centre as supplementary publication no. CCDC-100021 (Za). -100020 (6).
and -100025 (9) Copies of the data can be obtained free of charge on apphcation to The Director, CCDC. 12 Union Road, Cambridge CB2 1EZ. UK (fax:
int. code + (1223) 336-033; e-mail:
[31] For other examples of this binding pattern, see P. L. Andreu, J. A. Cabeza, A.
Llamazares. V. Riera, S. Garcia-Granda, 3. F. van der Maelen, J Orgunomer.
Deeming, R. Peters, M. B. Hursthouse, J. D. BackChem. 1992.434. 123; A. .I.
er-Dirks. J Chfwn. Soc Dulron Trans 1982, 1205.
[32] M. Kita. M. Nonoyamd, Polyhedron 1993. 12, 1027.
tals (containing 62.2 % DMSO) proved to be stable in the presence of the mother liquor at higher temperatures and could be
completely redissolved only at 80- 100 "C.
The resorcarene 1 indeed adopts the C,, symmetrical chair
conformation (Figure
in which two opposite aryl rings of
the macrocyclic framework are almost coplanar (the deviation
Quasi-Complete Solvation of Organic Molecules
in the Crystalline State**
Alexander Shivanyuk, Erich F. Paulus,
Volker Bohmer,* and Walter Vogt
The solvation of biologically important molecules with water
has been intensively studied by X-ray diffraction. The structural
information obtained from such studies provides valuable insights into the role of solute-solvent interactions for crucial
processes like protein folding or DNA double helix formation."] Examples of crystal structures of more simple compounds like cyclodextrinsrZ1and calixarenesr3]containing many
water molecules per unit cell are also known. In the latter case
bilayers of the sulfonated calixarene anion held together by
hydrophobic forces are separated by water-rich layers containing the cations. However, these structures, dubbed "organic
clays", provide little or no information on the solvation of the
single molecules in solution. Here we describe the quasicomplete solvation of resorcarene 1 '] by dimethyl sulfoxide
(DMSO) and pyridine (Pyr) in the crystalline state.
Acid-catalyzed condensation of resorcinol with 4-hydroxybenzaldehyde in EtOH
at room temperature led to a
mixture(61from which the rctt
isomer by
could berecrystalisolated
lization. The rigidity of its
macrocyclic skeleton comD,.*s
pletely excludes the formation
of intramolecular hydrogen
groups, contrary to the rccc
isomer.'*l We therefore expected that 1 would form supramolecular structures in the crystalline state, held together by intermolecular hydrogen bonds
between different resorcarene molecules.[91
Slow recrystallization of 1 from DMSO at room temperature
(20-23 "C) gave colorless crystals of the composition
1.18 DMSO which, although extremely unstable without solvent, were suitable for X-ray structure
These crysno
Dr. V. Bohmer, Dr A. Shivanyuk, Prof. Dr. W. Vogt
lnstitut fur Organische Chemie der Universitit
J.-J.-Becher-Weg 3 SB1, 0-55099 Mainz (Germany)
Fax. Int code +(6131)395419
e-mail: bboehmer(u
Dr E. F Paulus
Hoechst AG. D-65926 FrankfurtiMain (Germany)
This work was supported by the Deutsche Forschungsgemeinschaft and by the
European Community.
A n w . . (%em. In!. Ed. Engl. 1997, 36, N o . 12
Figure 1 Molecular conformation and numbering scheme of resorcarene 1 (20%
thermal elipsoids are shown)
between their planes is 0.35
and two others are nearly perpendicular to this plane (dihedral angle: 85.9?) with their hydroxy groups pointing in opposite directions. (Since molecule 1
has a crystallographic inversion center, opposite aryl rings must
be parallel.) The phenolic rings connected to the bridging carbon atoms assume the axial positions; two of them point up and
two down leading to dihedral angles of 83.0 and 88.8" with the
coplanar resorcinol rings. These pairs of cis-oriented phenolic
rings are almost parallel (dihedral angle: 8.4 ), and their hydroxy groups (03H and 06AH) together with those of the vertically oriented resorcinol ring (01H and 02H) form a polar
"cap" of the molecule.
The distances between neighboring oxygen atoms of the reand of
sorcinol rings (01-04A = 4.00 and 0 2 - 0 5 = 4.02
the cis-oriented phenolic moieties (06-03A = 4.54 A) are too
long to allow intramolecular hydrogen bonding and therefore
twelve intermolecular hydrogen bonds pointing in all directions
are formed to twelve DMSO molecules. Six additional DMSO
molecules fill voids in the crystal lattice (Figure 2). The distances between the oxygen atoms of hydroxy groups and the
hydrogen-bonded DMSO molecules are between 2.58-2.81 A.
Both the shortest and the longest distances were found for the
para-hydroxy groups 0 3 H and 06H.
All 18 (nine crystallographically independent) DMSO molecules are located at definite positions; however, their sulfur
atoms are disordered between two sites above and below the
triangle formed by the oxygen and the two carbon atoms (Figure 2 top). The site occupation probabilities for those two positions could be exactly determined for each sulfur atom. They
vary between 0.51 and 0.93. Four of them arc within 0.51-0.57
(Sl, S3, S6, S7), suggesting that there is almost no preference for
any position. Values between 0.73 and 0.93 for S9, S8, S2, S4,
and S5 demonstrate an increasing preference for one site.
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molecular, cyclic, rectangles, metali, boxes, nucleobases, complexes, heterocyclic, othet, hexagons
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