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Hypothetical Carbon Modifications Derived from Zeolite Frameworks.

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Experimental Procedure
All operations were carried out under a nitrogen atmosphere in dry, N,-saturated solvents. Compound 3 was prepared according to refs. [5,6]. Anhydrous
CoCI, was purchased from Merck-Schuchardt, Hohenbrunn near Munich.
To a suspension of 3 (7.625 g, 19.49 mmol) in toluene (75 mL). anhydrous
CoCI, (1.265 g, 9.74 mmol) was added. After the mixture had been heated and
stirred under reflux for 5 h, elemental magnetic cobalt and LiCl precipitated
from the dark red reaction mixture. The mixture was filtered and the filtrate
concentrated to a fifth of its volume. Compound 5, which precipitated as a
red-black, crystalline solid, was purified by recrystallization from hot toluene.
Finally. it was dried in vacuo for 48 h. Yield: 3.67 g (92%). Single crystals of
5 were obtained by layering a saturated solution of5 in CH,CI, with n-pentane
at room temperature. Correct elemental analysis (C,H,N,P,Co); decomposition
at 227 "C. 'H NMR (270 MHz. CD,CI,): 6 = 8.51 (s, 32H; C,H,), 7.70 (s, 4 H ;
C6H5). 7.37 (s, 12H; C,H,), 2.95 (br. s, 12H; C6HJ [12]; "C{'H} NMR
(67.94 MHz. CD,CI,): 6 =131.0 (s, C-ortho; C,H,), 128.2 (s, C-pura; C,H,),
127.2 (s, C-mera: C6H,), 119.5 (br s, C-ipso; C6H5) [12]; 3'P{lH) NMR
(109.38 MHz, CD,CI,; H,PO,): 6 = -150 (s, half-value width 125 ppm) [12].
IR(KBr):i.[cm-'][17] = 3070 w-m,3051 m[v(CH)], 1584 m, 1478 m-s, 1432 s
[v(CC)], 1303 m[b(CH)], 1192 vs, 1170s[v(P = N)]; 1132 vs[P-sens. q, Pv][18].
1093 s [P-sens. q, P"'] [18], 1046 m-s [v(P=N)]. 1026 m [S(CH)],997 m [C,H,ring vibration.]: 807 s [v(PN)]; 735 s [7(CH)]; 714 m-s [P-sens. r, P"] [18], 693 vs
[@(CC)l[18]. 676 m-s [v(PN)I, 568 m, 552 m-s [y(P-N-P)], 537 s [P-sens. y. P']
[18]. 515 s, 490 rn-s [P-sens. y. Pi"] [18], 427 m [P-sens. t, P-C,H,] [18]; 368 m,
br [S(NP,)I. FD-MS: mi; 1225 ( M ' ) .
The LiCl was extracted with T HF from the above-mentioned residue of LiCl
and pyrophoric cobalt metal and determined qualitatively. After the remaining
crude cobalt was dried it weighed 362 mg (6.14 mmol; corresponding to 63%
of the amount of Co used) and the content of pure Co was determined complexometrically to be 98.5% after transformation into CoSO,. Identification of 6 :
The volatile components of the combined filtrates of 5 were removed under
vacuum. The pale brown residue was eluted with toluene (25 mL) and the
solution was layered with n-pentane (35 mL), leading to a crystal conglomerate
of colorless, clear. square crystals of 6 , which were embedded in a microcrystalline thin layer of 5 . Crystals of 6 were removed mechanically, separated, and
analyzed [lo].
Received: November 12, 1992 [Z5679IE]
German version: Angen. Cliem. 1993. i05,763
[l] D. L. Herring, C. M. Douglas, Inorg. Chem. 1964.3, 428.
[2] H. W. Roesky. K. V. Katti, U. Seseke, M. Witt, E. Egert, R. Herbst, G. M.
Sheldrick, Angew. Chem. 1986,YX, 447; Angen. Chem. Int. Ed. Engl. 1986,
2s. 477.
[3] K. V. Katti, H. W. Roesky, M. Rietzel, Inorg. Chem. 1987, 26, 4032.
141 H. Schmidbaur, F. E. Wagner, A. Wohlleben-Hammer, Chem. Ber. 1979,
112, 496.
[5] J. Ellermann, M. Lietz, 2. Naturforsch. B 1980, 35, 64.
[6] A. Schmidpeter, F. Steinmuller, W. S. Sheldrick, 2. Anorg. Allg. Chem.
1989,579, 158.
[7] According to replacement nomenclature:[*]undecane.
[8] J. Ellermann, W. Wend, J Organomet. Chem. 1985,281, C29-C32.
[9] J. Ellermann, E. Kock, H. Zimmermann, M . Gomm, Acra Crystullogr.
S e a C 1987,43, 1795.
[lo] A correct C,H,N elemental analysis was obtained for the white crystals of
6. On the basis of MS, 'H{"P} NMR, 31P{'H} NMR, and IR spectra
(KBr) (3 v(PN): 873(w-m), 841 (s), 828(s) cm-') compound 6 is identical
with a sample of N(PPh,), prepared by a different route [XI and characterized by X-ray crystallography [9]. The IR spectrum allows a rapid and
clear distinction from the isomeric Ph,P-P(Ph),=N-PPh,;
1160(s)cm-'. See also: H. Noth, L. Meinel, Z. Anorg. ANg. Chem. 1967.
34Y. 225; H. Schmidbaur, S. Lauteschlager, F. H. Kohler, J . Organomet.
Cliem. 1984, 271, 173.
[11] Crystal structure analysis of5: red-black, prismatic single crystals with the
dimensions 0.4 x 0.4 x 0.3 mm obtained from CH,Cl,/n-pentane and measured at 293 K . Triclinic, space group P i ; Z = 2; u =1289.4(5), b =
1317.1(6), c = 2036.0(8) pm, OL = 82.86(3). 3! = 82.10(3), 7 = 63.44(31",
V = 3.040(3) nm3, pcalrd
=1.34 gem--'; w scan, 3.0 < w < 30"min-',
3' < 20 < 54' (Mo,,, 2. =71.073 pm, graphite monochromator). Of
13428 independent reflections 7247 have F < 4u(F). SHELXTL-PLUS,
direct methods. anisotropic refinement of the non-hydrogen atoms, the
positions of the hydrogen atoms of the phenyl groups were taken from the
difference Fourier synthesis and retained in the refinement, hydrogen
atoms with fixed isotropic temperature factor. R = 0.037, R, = 0.033.
Further details of the crystal structure investigation may be obtained from
the Fachinformationszentrum Karlsruhe, Gesellschaft fur wissenschaftlich-technische Information mbH, D-W-7514 Eggenstein-Leopoldshafen 2 (FRG) on quoting [he depository number CSD-320581, the names
of the authors, and the journal citation.
Angel!. Chem. Inr. Ed. Engl. 1993. 32, N o . S
[121 Magnetic moment: per,= 2.39(+0.15) {fix. The paramagnetism of the
cobaltfii) ion. corresponding to an unpaired electron, leads to paramagnetic shifts and line broadening in the NMR spectra (see Experimental Procedure), which make an interpretation more difficult.
[13] N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, Pergamon
Press, Oxford, 1984, p. 627.
[14] G . Dyer, D. W. Meek, J . Am. Chern. Soc. 1967,89, 3983.
[15] J. Ellermann, W. H. Gruber, Z. Anorg. Allg. Chem. 1969. 364, 55.
[16] The band assignment assumes an ideal C,, symmetry and refers to the
orbital and energy level diagram given in ref.[l4].
[17] Abbreviations: vs = very strong, s = strong, m = medium. w = weak,
br = broad.
[18] Designation according to D. H. Whiffen, J . Chem. S o [ . 1956, 1350.
Hypothetical Carbon Modifications Derived
from Zeolite Frameworks**
By Reinhard Nesper,* Karlheinz Vogel, and Peter E. Blochl*
Dedicated to Professor Hartmut Barnighausen
on the occasion of his 60th birthday
The discovery of fullerene modifications of carbon, in particular C,,, and their laboratory-scale production have stimulated a large number of theoretical and experimental investigations.['+1' Interest in the potential of carbon to form new,
exotic structures with surprising physical properties has
grown. Recent studiesr3- have concentrated on graphiterelated materials such as fullerenes, graphitic microtubules,
and negatively curved graphitic carbon--compounds composed of sp2-hybridized C atoms. Surprisingly, only few reports on modifications with sp3-hybridized C atoms have
appeared.['] Such compounds are likely to exhibit a structural variety rivaling that of the graphite-related materials
that are currently attracting a great deal of attention. The
stability of the C-C single bond is manifested in diamond; its
bond energy is only 0.02eV per atom less than that of
graphite. Compounds made up of tetrahedral building
blocks such as group 14 elements (C, Si, Ge, Sn, Pb) as well
as solid H,O and SiO, are known for their complex structural chemistry. The existence of amorphous silicon and carbon and of crystalline and glassy silicates indicates the enormous structural variety and kinetic stability of arrangements
of these building blocks.
We investigated ordered carbon modifications with sp3 C
atoms which are derived from structures found in nature,
Zeolite frameworks consist of tetracoordinated MO,,, units (M = Si, Al, etc.). Formal replacement
of each MO,,? unit by one carbon atom and appropriate
rescaling provides the desired model structures. We took all
known zeolite structures"01 into account but have omitted
those containing three- and four-membered rings. Six candidates remained for further investigation.
In order to determine the energetic stability of these six
carbon allotropes we performed electronic structure calculations. We used the ab initio molecular dynamics method of
[*I Prof. Dr. R. Nesper, Dr. K. Vogel
Laboratorium fur Anorganische Chemie der Eidgenossischen Technischen
Universitatstrasse 6, CH-8092 Zurich (Switzerland)
Telefax: Int. code + (11252-8935
Dr. P. Blochl
IBM Research Division, Zurich Research Laboratory
Saumerstrasse 4, CH-8803 Ruschlikon (Switzerland)
[**I This work was supported by the Schweizerische Nationalfonds zur
Forderung der wissenschaftlicben Forschung.
Q VCH Verlug.~~e.~ellschuft
mbH, W-6940 Weinheim,1993
10.00+ ,2510
Car and Parrinello["] based on the local density approximation (LDA)'"] in combination with the projector-augmented (plane) wave (PAW) method developed by one of us
(P.E.B.).[201The PAW method overcomes the well-known
problems in the application of the pseudopotential method
to first-row and transition metal elements by expanding the
electronic wave functions in augmented plane waves. It has
been successfully applied to several systems such as small
and large molecules and surfaces," 31 and the solid-state systerns here. The accuracy of the PAW method is comparable
to that of state-of-the-art pseudopotential and linear augmented plane wave methods. The Car-Parrinello technique
was used here to optimize the trial structures without imposing symmetry or other constraints.
In the present study we used augmented plane waves up to
a kinetic energy of 25 Ry (1 Ry = 13.605804 eV). An increase to 35 Ry provided the same results. Our calculations
are based on supercells for which the product of the number
of atoms and the number of reciprocal lattice points k ( N
(atoms) x N(k-points)) is between 92 and 136. Table 1 contains selected calculated energies for the zeolite-derived carbon modifications.
Table 1 . Hypothetical carbon modifications. The columns contain the designation, the structure type. the energy difference A E [eV] in cohesive energy per
atom relative to diamond, and the LDA band gaps EG [eV].
Structure type
zeolite ZSM-39
zeolite ZSM-23
zeolite Theta-1
Fig. 2 . Structure of C,,,. which corresponds to the clathrate 1 structure (purple- C, pentagonal dodecahedra. orange: C,, cages.)
C,,, and C,, correspond to the well-known clathrate I
and clathrate I1 structures, respectively (Figs. 2 and 3),
which are found in a number of isoelectronic compounds
like [As,G~,,]I,,['~I [Ge46-xIx]18 with x = 8/3,1'61 and
Na,[Si,,,] with x = 3-11.1171[*1Both structures are space-
The energy-volume dependence is shown in Figure 1. All
but one of the structures investigated are energetically favored over C, ,which according to LDA calculations[61and
e ~ p e r i m e n t " ~is] higher in energy than diamond by 0.42 eV
and 0.38 eV per atom, respectively. C,,, and C,,
have the
Fig. 3. Structure of .,C
which corresponds to the clathrate I1 structure. The
large C2Hcages (yellow) form a superdiamond framework, the pentagonal
dodecahedra C,, (purple) a supertetrahedron.
V/V IDIA) ---+
Fig. I. Energy-volume diagram of hypothetical carbon modifications. Energy
differences and volumes are given per C atom and scaled relative to diamond.
V (DIA) refers to the experimentally determined volume of diamond.
lowest energies ever calculated for any hypothetical carbon
modification^.[^-'^ In the following discussion we will concentrate on these two compounds.
f.3 VCH VerlagsgesellcrAaft m6H. W-6940 Weinhrim. 1993
filling arrangements of face-sharing fullerene-like cages with
twelve pentagons and zero, two, or four hexagons. It is interesting that the structural patterns in C,,, and C,,
are similar to those in the fullerenes despite the grossly different
bonding (sp3 vs. sp2 hybridization). In these polymeric allotropes the minimal difference between the bond angle in a
Framework atoms in brackets; the counterions
0570-0833~93/0505-0702h' 10.00
+ .25/0
1- and N a + occupy the
Angew. Chem. h r . Ed. Engl. 1993. 32, N o . 5
five-membered ring (108 ") and in an ideal tetrahedron
(109.47 ',) accounts for the stability. An ideal structure composed of sp3 C atoms would therefore contain solely facesharing pentagonal dodecahedra. However, as it is impossible to build an infinite structure from pentagonal dodecahedra alone, six-membered rings are required even though
they introduce greater ring strain. With this general building
principle, namely face-sharing fullerene-like cages, it is possible to construct a large class of polymorphic solids that are
expected to be similar in energy to the ones we have studied.
Recently Guo et al. proposed structures for transition metal
carbide clusters forming face-sharing pentagonal dodecahedrd."81 The structures of C,,, and C,,
can be considered
extensions of these clusters to bulk structures (cf. Figs. 2,3).
C,,, and C,,, exhibit large band gaps that are even 6 and
23 o/o smaller than that of diamond. (These numbers should
be taken with a grain of salt as the LDA does not in principle
allow the prediction of excitation energies. Trends, however,
are usually well reproduced.) These hypothetical carbon
modifications have a number of interesting characteristics.
The large cages might accommodate interstitial dopant
atoms providing a means to engineer their electronic and
optical properties. The nearest-neighbor distances for the
interstitial sites within the various fullerene-like cages are
207 and 255 pm for C,,, and 215 and 223 pm for C,,,,
compared to 153 pm in diamond. The first value always
refers to the nearest-neighbor distance in pentagonal dodecahedron. The average volume per atom is increased by
about 2 5 % over diamond but considerably less than in
graphite (1 53 Yo) and in solid C,, (205 YO).
We expect C,,, and C,,, to exhibit high mechanical stability once they are formed, as a result of their low energy
difference compared t o C,,, , the large energy required to
break a C-C bond, and the three-dimensional linkage of the
network C atoms.
Currently we are investigating whether the new structures
can be identified in the products formed by the Kratschmer
process. High-pressure experiments on C,, are being performed as ~ e 1 l . I An
' ~ ~alternate synthetic route would the
epitaxial growth of these solids on, for example, the carbide
clusters of Guo et aI.[''l
Received: May 19, 1992
Revised version: February 1. 1993 [Z5361 IE]
German version: Anxeu. Chem. 1993. 105, 786
[ l ] H. W. Kroto. J. R. Heath, S. C. O'Brien, R. F. Curl, R F. Smalley, Nuture
1985. 318, 162.
[2] W. Krdtschmer, L. D. Lamb, K. Fostiropoulos, D. R. Huffman, Nature
1990. 347, 354.
131 T. Lenosky. X. Gonze, M . Teter, V Elser, Nulure 1992, 355, 333.
141 D. Vanderbilt. I Tersoff. Ph?.s. Rev. LEI!. 1992, 68,511.
[5] M O'Keeffe. G . B. Adams, 0 . F. Sankey, Phyr. Rev. Lett. 1992, 68.
161 G. B. Adains. 0. F. Sankey, J. B. Page, M. O'Keeffe, D. A. Drabold. SCIc m c 1992. 2%. 1792.
171 S. J. Townsend. T. J. Lenosky. D. A . Muller, C. S. Nichols, V. Elser. Plrys.
Rri.. Lctt. 1992, 6Y. 921.
[XI N. Hamada. S. Sawada, A. Oshiyama, Pliw R e v Lett. 1992, 68.
[9] R . L. Johnston, R. Hoffmann. J. .Am. Chem. Soc. 1989, 111, 810; R.
Bhuas. R. M. Martin, R. J. Needs, 0. H. Nielsen, P/IJ.T. Rev. B 1987, 35,
9550; ihid. 1984, 30. 3210; M. T. Ym. ibid. 1984, 30, 1773.
[lo] W M Meier. D. H. Olson, Atlu.5 of Zeolite Srrucrurr ~ ~ p e Butterworths,
London. 1987. The carbon modifications are designated by C,,,,, where
ABC refers to the notation of the corresponding zeolitc.
[I 11 R. Car. M. Parrinello. P ~ I J ARev.
. L ~ f r 1985.
55. 2471.
[13] Wc used the results of D. M. Ceperly and B. J. Alder (Pliys. Rev. Letr. 1980.
45. 566) for the homogeneous electron gas in the parametrization of J. P.
Perdew and A. Zunger (Pi7y.s. Rev. B 1981, /O. 504X).
[13] A. J. Fisher. P. E. Blochl. Phvs. Rev. Lett., submitted.
[14] H:D. Beckhntis. C. Riichardt, M. Kao, F. Diederich, C. S. Foote, Anxrw.
C'hivn. 1992. 104, 69: Angeii.. Chem. Inr Ed. EnxI. 1992, 31, 63.
Angcw. C'iirm. In/. Ed. Engi.
1993,32, No 5
1151 H Menke, H. G. von Schnering, Nuturni.ssmsch~/ten1972, 59. 420.
1161 R. Nesper. J. Curda, H. G. von Schnering, Angew. Chew. 1986, Y8, 369;
Angen. Chem. h t . Ed. Engl. 1986, 25, 350.
[17] C. Cros, M. Pouchard, P. Hagenmuller, C. R. Hehd. Srunces Acud. Sci
1965. 260,4764; J. Solid Slule Chem. 1970, 2, 570.
1181 B. C. GUO,K. P. Kerns, A. W. Castleman, Science 1992, 25S, 1411; B. C.
Guo, S. Wei, J. Purnell, S. Buzza, A. W. Castleman, ibid. 1992.256,515: S.
Wei, B. C. Guo, J. Purnell, S. Buzza, A. W. Castleman, ihrd. 1992.256.818.
1191 M. Worle. K . Syassen, R. Nesper, unpublished.
[20] P. E. Blochl, P h w Rev. B, submitted.
Self-Assembly, Structure, and Spontaneous
Resolution of a Trinuclear Triple Helix from
an Oligobipyridine Ligand and Ni" Ions **
By Roland Kramer, Jean-Marie Lehn,* Andrk De Cian, and
Jean Fischer
Double-helical metal complexes, termed helicates, have
been shown to form by the spontaneous assembly of oligo2,2'-bipyridine (bpy) strands and metal ions that favor tetrahedral coordination geometry, such as Cu' and Ag'." -31
Complexes containing from two to five metal centers, that is,
di- to pentahelicate species, have been obtained thus." -41
Helicate formation is a self-organization processr5]displaying positive cooperativity.[61It results from the tetrahedral
coordination imposed by each Cu(bpy),+ site and from the
design of the ligands. These two features constitute, respectively, the recognition event and the molecular steric "instruction" that lead to the preferential generation of doublehelical structures. In the general context of programmed
supramolecular systems,"] helicate formation may be described as the result of the reading by metal ions of the
molecular information stored in the oligo(bpy)strands following a tetrahedral coordination algorithm.[s.
A number of double helical complexes involving other
ligand molecules and presenting two metal centers have been
reported.['- l 3 I When the hgand contains two['4or
three[171terpyridine units, double-helical complexes with
two or three octahedral metal centers, respectively, may be
The steric information contained in the oligo(bpy)strands
yielding double helicates resides in the disposition of the
nitrogen sites and in the 6,6-disubstitution of the bpy
units." -'I The latter hinders the binding of metal ions that
prefer octahedral coordination geometry, which would be
expected to yield triple helicates. This might, however, become possible through a slight modification of the steric
instruction by shifting from a 6,6- to a 5,S-disubstitution.
We now report that the trinuclear triple-helical complex 1 is
indeed formed spontaneously by self-assembly from three
5,5'-disubstituted tris(bpy) strands 5 and three Ni" ions.
A triply bridged dinuclear Fe" complex of a bis(bpy) ligand" and probably also a related bis(Fe") complex possess
triple-helical features." 21 A triple-helical arrangement has
been assigned to dinuclear Fe"' complexes of tripodal ligands
on the basis of NMR and circular dichroism (CD) data.'"]
[*] Prof. Dr. J.-M. Lehn, Dr. R. Kramer
Laboratoire de Chimie Supramoleculaire
lnstitut Le Bel, Universite Louis Pasteur
4. rue Blaise Pascal, F-67000 Strasbourg (France)
Telefax: Int. code + (88) 41-1020
Prof. Dr. J. Fischer, Dr. A. DeCian
Laboratoire de Cristallochimie el de Chimie Structurale
Institut Le Bel, Universite Louis Pasteur, Strasbourg
This work was supported by the CNRS (URA 422 and URA 424). R. K.
thanks the Deutscher Akademischer Austauschdienst for a post-doctoral
research fellowship. We thank Dr. Masayuki Takahashi and Matthias
John for help with circular dichroism measurements.
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hypothetic, framework, zeolites, modification, derived, carbon
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