Preparation and Structures of Metal Anion “Cubes” in Zeolites. Implications for Application Including Catalysis

Chemistry Department, University of Hawaii

Lead easily forms Pb₄O₄ cubes (distorted cubes with tetrahedral symmetry) in the sodalite cavities of zeolite X upon ion exchange with Pb²⁺ and vacuum dehydration at ca. 400 ^oC. Similarly La³⁺ and water form La₄O₄ cubes laced together at each La³⁺ corner by an oxide ion, leaving many H⁺ ions free for acid catalysis, which is important to the petrochemical industry. Cd₆S₄⁴⁺ cations with Cd₄S₄ cores have been prepared in zeolite A, as have the photosensitive Ag₄X₄ clusters (X = Cl^-, Br^-, I^-). Ni₈O₄⁸⁺ clusters with Ni₄O₄ cores have been found in zeolite Y, together with three-coordinate Ni²⁺. Ni-Y is effective in the oxidation of NO_x and both the hydrogenation and oxidation of CO. Cubic clusters of In₄(OH)₄⁸⁺ in zeolite Y may participate directly in catalysis by donating H⁺ ions and accepting them back later in a catalytic cycle, and they may do the same with pairs of electrons, much like the Fe₄S₄ cubes in enzymes. In zeolites, indium catalyzes alkylation and alkyl transfer in aromatics, the benzoylation of naphthalene, the conversion of methane to higher hydrocarbons, and the reduction of NO_x by hydrocarbons at practical conditions.

Autobiosketches

KARL SEFF, a curriculum vitae

Chemistry Department, University of Hawaii

2545 The Mall, Honolulu, Hawaii 96822-2275

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B. Education

1.	U.C.	Berkeley	1955 to 1959	B.S.	6/59	Physical Chemistry
2.	M.I.T.	Cambridge, Mass.	1959 to 1964	Ph.D. with D.P. Shoemaker	9/64	Physical Chemistry and crystallography
3.	M.I.T.	Cambridge, Mass.	1964	Postdoctoral work with D.P. Shoemaker	11/64	Zeolite powder crystallography
4.	U.C.	Los Angeles	1965 to 1967	Postdoctoral work with K.N. Trueblood	6/66	Single-crystal crystallography

C. Positions held

1.	7/66 - 1/68	Assistant Research Chemist	U.C.L.A.	Computer liaison X-ray crystallography
2.	2/68 - 6/73	Assistant Professor	U. Hawaii	Chemical crystallography
3.	7/73 - 6/75	Associate Professor with tenure	U. Hawaii	Chemical crystallography
4.	10/74 - 2/75	Visiting Scholar	Princeton	Zeolite catalysis
5.	7/75 - 12/06	Professor	U. Hawaii	Chemical crystallography
6.	10/81 - 5/82	Associate Researcher	U. Mexico	Crystallography
7.	7/88 - 12/88 6/89 -12/89	Visiting Scholar	Oxford,UK	Zeolite crystallography Rietveld refinement
8.	1/89 - 6/89	Visiting Professor	Dartmouth	Crystallography
9.	7/96 -12/96	Visiting Scholar	Korean Univs.	Zeolite crystallography
10.	1/00 - 6/00	Associate Chair, Chemistry	U. Hawaii
11. 12.	7/00 - 6/03 1/07 - present	Chair, Chemistry Professor Emeritus	U. Hawaii U. Hawaii	Zeolite chem. & crystallogr.

E. Membership in societies

American Crystallographic Association, since 1962
American Chemical Society, since 1972
International Zeolite Association, since 1973

F. Theses by students working under my direction: 12 Ph.D. and 19 M.S.

G. 3 US Patents and over 240 publications

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Preparation and Structures of Metal Anion “Cubes” in Zeolites. Implications for Application Including Catalysis