Event Title

Spontaneous Dehydration and Polycatenation of Benzene-1,3,5-tricarboxylic Acid Lattices: AModel System for Understanding the Crystallization of 1,3,5-tris(4-carboxyphenyl)benzene

Presenter Information

Andrea Goltz, Oberlin College

Location

Science Center, Bent Corridor

Start Date

10-2-2015 12:00 PM

End Date

10-2-2015 1:20 PM

Poster Number

5

Abstract

The crystallization of 1,3,5-tris(4-carboxyphenyl)benzene, tcpb, has proven challenging for past research groups. Only recently has single-crystal X-ray diffraction (XRD) revealed that the difficulties with crystallization likely stem from a complicated pattern of polycatenated hydrogen-bonded hexagonal sheets. The structure of tcpb is of interest to crystal engineers as it exhibits nanoporosity in the solid state and to crystallographers as one of its polymorphs has a Z’ of 56 independent molecules. Examples of organic crystals that retain their pore architectures upon evacuation of trapped solvent are rare; however tcpb is an exception, making it a promising material for gas storage and separations. In this project, we hope to elucidate the fundamental challenges underlying the crystallization mechanism of tcpb by studying solvated, kinetically-stable, and non-catenated crystallization intermediates of benzene-1,3,5-tricarboxylic acid, H3btc. H3btc, a simpler analogue of tcpb lacking phenylene extensions between the central benzene ring and carboxylic acid groups, displays polycatenation patterns similar to those of tcpb and can thus be used as a simplified structural model for tcpb. Additionally, we seek to determine the appropriate crystallization conditions to reliably select for each H3btc crystal form and most importantly, to control polycatenation in H3btc crystal structures with the goal of isolating the non-catenated porous H3btc polymorph.

Major

Chemistry; Geology

Project Mentor(s)

Ren Wiscons, Chemistry and Biochemistry
Jesse Rowsell, Chemistry and Biochemistry

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Oct 2nd, 12:00 PM Oct 2nd, 1:20 PM

Spontaneous Dehydration and Polycatenation of Benzene-1,3,5-tricarboxylic Acid Lattices: AModel System for Understanding the Crystallization of 1,3,5-tris(4-carboxyphenyl)benzene

Science Center, Bent Corridor

The crystallization of 1,3,5-tris(4-carboxyphenyl)benzene, tcpb, has proven challenging for past research groups. Only recently has single-crystal X-ray diffraction (XRD) revealed that the difficulties with crystallization likely stem from a complicated pattern of polycatenated hydrogen-bonded hexagonal sheets. The structure of tcpb is of interest to crystal engineers as it exhibits nanoporosity in the solid state and to crystallographers as one of its polymorphs has a Z’ of 56 independent molecules. Examples of organic crystals that retain their pore architectures upon evacuation of trapped solvent are rare; however tcpb is an exception, making it a promising material for gas storage and separations. In this project, we hope to elucidate the fundamental challenges underlying the crystallization mechanism of tcpb by studying solvated, kinetically-stable, and non-catenated crystallization intermediates of benzene-1,3,5-tricarboxylic acid, H3btc. H3btc, a simpler analogue of tcpb lacking phenylene extensions between the central benzene ring and carboxylic acid groups, displays polycatenation patterns similar to those of tcpb and can thus be used as a simplified structural model for tcpb. Additionally, we seek to determine the appropriate crystallization conditions to reliably select for each H3btc crystal form and most importantly, to control polycatenation in H3btc crystal structures with the goal of isolating the non-catenated porous H3btc polymorph.