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Amorphous Zeolites.

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[I1 H . A. Szymanski. C. N . Slamires, G. R. Lynch, J . Opt. SOC.Am. 50, 1323
( 1960).
12) J. B. Uyfferhoeuen,L. C. Chrismer, W. K . Hall, J . Phys. Chem. 69, 2117
(1965): C H . Kuhl in J. B. Uyfterhoeuen: Molecular Sieves. Leuven Universty Press, Leuven 1973. p. 227; D. W. Breck, G. W. Skeeis, ACS Symp. Ser.
40, 271 (1977); P. A. Jacobs. H. K. Beyer, J . Phys. Chem 83, 1174 (1979): J.
V Smirh. Adv. Chem. Ser. 101, 183 (1971).
I31 G. T. Kerr, J . Catal. 15. 200 (1969).
[4] R. M. Millon, US-Pat. 2882244 (1959); D. W Breck, US-Pat. 3130007
(1964).
[ S ] R. Beoumonr, D. Barfhomeuf; Y. Trambonze, Adv. Chem. Ser. 102, 327
(1971).
Amorphous Zeolites
By John M . Thomas and Leslie A . Bursill"]
Crystalline zeolites possess a wide range of properties that
make them industrially important. It is less widely known
that imperfectly-ordered (quasi-crystalline or semiamorphous) zeolites also exist, and that these, too, possess potentially attractive properties. There is, however, some difficulty
in characterizing these amorphous variants; and it is rather
puzzling that a material which lacks long-range order can
nevertheless exhibit marked cation-exchange capacity and
catalytic activity, which in the case of the crystalline varieties, arise because of the unit-cell level porosity of the aluminosilicate. Our communication focuses on these two points;
and, in particular, describes how high resolution electron microscopy (h.r.e.m.) helps rationalize these problems.
We have recently shown"] that it is possible, notwithstanding their beam-sensitivity, :t record direct structural images,
at a resolution close to 3 A, of crystalline zeolites such as
Na-A, Na-X, Na-Y and ZSM 5. During the course of
examination the zeolites gradually become amorphous; but
advantage may be taken of this fact since both the course of
the process of amorphization as well as the various degrees of
quasicrystallinity may be analyzed by direct (real-space)
imaging. (The reliability of the images taken by h. r. e. m.,
both for crystalline and amorphous materials, is known from
computer simulation procedures that are described fully else~here[~.~I.)
Considerable insight is gained from the study of amorphous zeolites in this way. This is illustrated with reference
to Fig. 1 which is a high-resolution image of a dehydrated
crystal of Na-A (idealized formula Na12AI12Sii2048)
that has
been appreciably converted to an amorphous condition141.
There are several noteworthy features:
(i) A 'raft' (ca. lo4 A' in projected area) of crystalline material consisting of an ordered array of so-called supercaged'l-ca.
lo2 in all-is surrounded by essentially
amorphous a1uminosilicate.(ii) A smaller 'raft' (ca. 3 x lo3A' in area), less well-ordered
than the other and not in registry with it, consisting of
some 30 supercages, is also surrounded by amorphous
material.
(iii) Several isolated supercages, one of which is arrowed,
may be identified in the amorphized background.
Fig. 1. High resolution electron micrograph of a thin film ( ~ 4 A0 thick) of quasi-crystalline zeolite A, showing the supercages as white dots. For details see text
Prof. Dr. J . M Thomas, Dr. L. A. Bursill [**I
Department of Physical Chemistry, University of Cambridge
Lensfield Road, Cambridae. CB2 IEP (Enelandl
[**I On leave from Department of Physics, University of Melbourne (Australia)
['I
.
Angew. Chem. Inr. Ed. Engl. I9 (1980) No. 9
L
I
We may now appreciate how amorphous zeolites can retain
much of their cation-exchange capacity: even though clusters
of sodalite cages (which circumscribe the supercage-see inset) are detached from the parent crystal, thereby generating
0 Verlag Chemre, GmbH, 6940 Weinheim, 1980
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745
a structure the long-range order of which is disrupted, these
sub-unit cell fragments still possess the basic attribute that
confers upon them their exchange capacity and catalytic activity.
Clearly h. r. e. m. can play a useful role in the characterization of microcrystalline and amorphous zeolites, more so perhaps than other solids since the individual units (in this case
the cubo-octahedra) are more readily discernible, and hence
the interpretation of image detail more straightforward.
Received: June 13, 1980 [Z 566 IE]
German version: Angew. Chem. 92, 755 (1980)
CAS Registry numbers:
N o compounds indexed
[ I ] L. A. Bursill, E. A . Lodge, J. M . Thomas, Nature 286, 1 1 1 (1980); J . M. Thomas, G.R. Millward, L. A . Burs;//, Phil. Trans. Roy. Soc., in press; L. A. Burs;//, €. A. Lodge, J. M . Thomas, J . Chem. Soc. Chem. Commun., in press.
[2] J. M. Cowky, Diffraction Physics. North-Holland, Amsterdam 1975.
[3] D.A . Jefferson, G R. Millward, J. M. Thomas, Acta Cryst. A 32, 823 (1976);
J. M. Thomas, D.A. Jefferson, Endeavour (New Series) 2. 127 (1978).
141 R. M. Bower, Zeolites and Clay Minerals as Sorbents and Catalysts. Academic Press, New York 1978.
Bis(rl-cyclopentadienyliron-~,q-thiadiborolene)ironStructure of a q-C5H5Tetradecker Sandwich
Complex[**'
By Walter Siebert, Christian Bohle, and Carl Kriiger[*l
the compound [(C5HS)Fe(C8H,2)]2Zn,
recently described by
Jonas et
with 1,2,5-thiadiborolene to give the trinuclear
complex (1) (58% yield) we have now found a route for the
synthesis of the long-sought sandwich anion (2)f41.We report
tetrahere on the first 9-cyclopentadienyl-p-thiadiborolene
decker sandwich complexes (4) and (5) which we obtained in
53 and 42% yield, respectively, from the anion (2) and FeC12
and CoCl2.
Direct reaction of ( I ) with C0C12 leads, as a result of ligand exchanges, to (C5Hs)Co(C2B2S)(83%), (C5H&Fe (70%)
and traces of (3). Reaction of (1) with FeCI2 in boiling tetrahydrofuran (THF) affords besides (3) and (4) (19%) the hydride complex [(C,H,)Fe(H) (C2B2S)], which contains a
Fe-H-B
3z/2e bond [6"B(CS2)=0.3 (br. s, I), 34.7 (s, l)].
This compound is also obtained on reaction of ( I ) with HClgas; the isomeric hydride complex [(C5H5)(C2B2S)Fe-H]
[G1'B(CS2)=25.3(s, 1), 38.7 (s, 1); 6'H(CS2)= -7.4 (Fe-H)]
is formed initially and is then converted thermally into the
compound with the Fe-H-B
bridgec4'.
The constitution of (4) follows from the spectroscopic data
[6'H(CS2)=3.52 (s, lo), 3.1 (m, 4), 1.9 (rn,4), 1.79 (s, 12),
1.22 (t, 12); 6"B(CS2)= 19.2; MS: m/e=630 ( M + , 100%)(70
eV)]. The "B signal indicates four equivalent boron atoms as
well as bifacial coordination of the thiadiborolene ligands.
The B-CH3 signal is consistent with a trans arrangement of
the p-ligands, which, as for the trinuclear complexes
is
[(CO)3Mn(C2B2S)]2Fe151
and [(C2B2S)Co(C2B2S)]2Fe1'1,
confirmed by the crystal structure analysis['] (Fig. 1).
Dedicated to Professor Karl Dimroth on the occasion of
his 70th birthday
Triple-decker complexes with terminal carbon monoxide
or thiaborolene ligands are cleaved by cyclopentadienide
into anionic mononuclear compounds which form tetradecker complexes with transition-metal halides'']. An analogous
cleavage of the q-cyclopentadienyl triple-decker sandwich
(3)l2] fails because of its short Fe.. .Fe distance. By reacting
Fe
Fe
,
6
-
9 -B,
Fe
Ct2
AC1
Fig I . Molecular structure of the complex (4) in the crystal
[*] Prof. Dr W. Siebert, Dr. C. Bohle
Fachbereich Chemie der Universitat
Hans-Meerwein-Strasse, D-3550 Marburg 1 (Germany)
Present addressAnorganisch-Chemisches Institut der Universitat
Im Neuenheimer Feld 270
D-6900 Heidelberg 1 (Germany)
Priv.-Doz. Dr C. Kruger
Max-Planck-lnstitut fur Kohlenforschung
Lembkestrasse 5 . D-4330 Mulheim-Ruhr 1 (Germany)
[**I Tetradecker Complexes, Part 3. This work was supported by the Deutsche
Forschungsgemeinschaft and the Fonds der Chemischen Industrk-Part 2: [r].
746
0 Verlag Chemie, GmbH, 6940 Weinherm, 1980
The distances between the ring atoms in the fi-ligands
are C-C= 1.461(3), B-C= 1.564(3), 1.556(3) and
B-S=1.909(2),
1.913(2) A, and in the 9-ligands
C-C= 1.405(4)-1.417(4) A. Fel ocFupies an inversion center, the Fel-Fe2 distance (3.272(1) A) is only slightly longer
than in (3) (3.236(1) A).
The distances between the metal atoms and the best
planes of
the ligands (D) [Fe-D(C,H,) = 1.67,
Fe-D(C,B,S) = 1.63, and Fel-D(C,B,S) = 1.64 A] are similar. I? contrast, strongly deviating distances (1.69, 1.60, and
1.93 A) were found in the tetradecker sandwich complex
0570-0833/80/0909-0746
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Angew. Chem. Int Ed. Engl 19 (1980) No. 9
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