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Dissertation Information for Jong Woo Han

NAME:
- Jong Woo Han

DEGREE:
- Ph.D.

DISCIPLINE:
- Chemistry

SCHOOL:
- Emory University (USA) (2006)

ADVISORS:
- Craig L. Hill

COMMITTEE MEMBERS:
- Karl S. Hagen
- Fred M. Menger

MPACT Status: Fully Complete

Title: Coordination polymers from redox-active bis(triester)hexavanadates and transition metal ions

Abstract: In our pursuit of developing catalytic porous coordination networks, we designed and prepared two redox-active bis(triester)hexavanadates, [V 6 O 13 {(CH 2 O) 3 CNHCO( 4 C 5 H 4 N)} 2 ] -2 and [V 6 O 13 {(CH 2 O) 3 CNHCO(4-C 6 H 4 COOH)} 2 ] -2 . These two bridging ligands readily react with transition metal ions to yield various redox-active open-framework materials. A pyridine-terminated bis(triester)hexavanadate, [V 6 O 13 {(CH 2 O) 3 CNHCO( 4 C 5 H 4 N)} 2 ] -2 , an analogue to 4,4\'-bipyridine, reacts with four divalent first-row transition metal ions (Mn II , Co II , Ni II or Zn II ) to produce one-dimensional (1D) coordination chains connected by hydrogen bonds. The materials can be chemically reduced and re-oxidized by dioxygen. However, the pyridine-terminated hexavanadate does not form stable open-framework structures. The benzoic acid-terminated hexavanadate assembled by d- (Co II ) and f-block (Gd III , Tb III , or Yb III ) elements form open framework materials. Lanthanides and the benzoic acid functional groups form paddle-wheel cluster moieties to generate two-dimensional layers interconnected by hydrogen bonds between a secondary amine moiety and a bridging oxo group of the POM.Among three f-block elements, only the Yb material maintains framework integrity. Thus, the coordination polymers assembled Yb catalyze aerobic oxidation of PrSH to its oxidized product PrSSPr in a heterogeneous fashion. More robust and sophisticated structures were fabricated by employing mixed-ligand approaches. In these approaches, the benzoic acid-terminated hexavanadate is mixed with conventional organic bridging ligands, such as 4,4\'-biphenyldicarboxylic acid, bis(4-carboxyphenyl)acetylene, or 4,4\'-bipyridine- N,N\' -oxide, and the combined ligand-mixtures are complexed with Co II , or Ln III (Ln = Tb, Gd, or Yb) to yield various open-framework materials. The combination of 4,4\'-bipyridine- N,N\' -dioxide, the benzoic acid-terminated bis(alkoxo)he xavanadate, and Tb III lead to pillared-layer type, three-dimensional net-work materials. Although the dimensions of channels are significantly diminished in the material, the network material successfully catalyzes two oxidation reactions: PrSH to PrSSPr by air and tetrahydrothiophene (THT) to tetrahydrothiophene oxide (THTO) by tert -butylhydroperoxide. This work show a new way of building up catalytic materials with well-defined catalytically active POM units.

MPACT Scores for Jong Woo Han

A = 0
C = 0
A+C = 0
T = 0
G = 0
W = 0
TD = 0
TA = 0
calculated 2008-02-24 22:22:27

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