I currently have three ongoing research projects under the umbrella of host-guest chemistry. The importance of this research is in understanding the structure and function relationship that is ubiquitous in biological systems. Interactions between a given guest molecule and its host molecule result in new physical and chemical properties that are characteristic of the host-guest complex.
The three projects are described below:
Project 1: Host/guest chemistry of cyclodextrin/spiropyran and cyclodextrin/merocyanine complexes-Photochromic conversion of spiropyran (closed ring form) into merocyanine (open ring form) allows for on-and-off optical switching applications. Photochromism is the color conversion of a solution due to presence or absence of light. Spiropyrans may potentially be used in the development of new materials for photochromic switches, photochromic lenses (optometry), fluorescent biomarkers, and drug delivery devices. We are interested in the chemical kinetics of spiropyran to merocyanine in neat solvents and aqueous binary media.
Project 2: Host/guest chemistry of cyclophane/spiropyran and cyclophane/aromatic compound complexes– This project is analogous to project 1 except that we have replaced the host molecule cyclodextrin with cyclophane. Moreover, we are interested in studying the interactions of cyclophane with several guest molecules: i.e., spiropyran, merocyanine, and aromatic compounds. The purpose of the cyclophane/aromatic compound project is to identify sensors for polycyclic aromatic hydrocarbons (PAHs) such as benzene, anthracene, etc, so that they can be detected and removed from the environment. PAHs result from the incomplete combustion of coal, oil, gas and other organic substances. PAHs are ubiquitous pollutants in the environment. In high concentrations, they constitute potential health hazards. Several PAHs either have mutagenic and carcinogenic properties or are precursors to carcinogenic compounds. Because of their potential health threats, remediation of PAHs from the environment is crucial.
Project 3: Host/guest chemistry of cyclodextrin/drug in neat and aqueous binary media – This project is also similar to project 1 except that the guest molecule is replaced with a drug. Meloxicam is a drug that has very low water solubility and it is used for treatment of various arthritic conditions including other joint diseases. Cyclodextrins are used extensively to enhance water solubility of hydrophobic drugs thus reducing the drug’s prescription concentration. This drug dose reduction also leads to decreased toxicity. We are interested in investigating optimum media conditions that will favor water solubility of meloxicam. Anticipated results from the proposed system may potentially be used for (1) improving drug delivery and (2) understanding the interaction chemistry of drugs and their receptors.
Tennis, walking, and Scrabble
Ph.D., University of Florida, Gainesville
B.A., Williams College
Katheryn Burke, Caterina Riccardi, and Thandi Buthelezi, “Thermosolvatochromism of nitrospiropyran and merocyanine free and bound to cyclodextrin” J. Phys. Chem. B, 2012, 116 (8), 2483.
Kamia K. Smith, Amanda V. Iwunze, Kathryn A. Burke, Pillhun Son, Malgorzata Sroweic, and M. Thandi Buthelezi, “Spectroscopic investigations of molecular association of cyclophanes with anthracene”, Arkivoc, (vii) 2010, 179. Invited commemorative issue for Prof. Richard A. Bartsch.
Christopher Davies, Li Ren, Ryan Gustafson, Thandi Buthelezi*, Richard A.Bartsch, Malgorzata Surowiec; “Molecular association of benzene with a new cyclophane receptor”; Journal of Inclusion Phenomena and Macrocyclic Chemistry, 61, 2008, 347.
Chemistry: Matter and Change, Thandi Buthelezi , Laurel Dingrando, Nicholas Hainen, Cheryl Wistrom, Dinah Zike; Glencoe/McGraw-Hill, ©2008
Molecular association of benzene with a new cyclophane receptor. Davies, Christopher; Ren, Li; Gustafson, Ryan; Buthelezi, Thandi; Bartsch, Richard A.; Surowiec, Malgorzata. Journal of Inclusion Phenomena and Macrocyclic Chemistry 61, 2008, 347.
Characterization of modified carbon nanotubes by TG-MS and pyrolysis-GC/MS. Lineberry, Quentin; Buthelezi, Thandi; Pan, Wei-Ping. Chemistry Department, Western Kentucky University, Bowling Green, KY, USA. Journal of ASTM International, 2006, 3(9).
Spectroscopic Properties of Cyclophane/Anthracene and Cyclophane/9-Fluorenone Complexes in Dichloromethane, Mark O≠Brien, Rachelle Smalley, Augustine Amonge, Scott Raber, Andrew Starosota, Thandi Buthelezi*, Richard A. Bartsch and Malgorzata Wegiel, Microchemical Journal, 80, 2005, 55.
Complexation Studies of Chlorophyll a with Trinitro Substituted Fluorene Derivates, R. Smalley, M. O’Brien, S. Raber, A. Amonge, J. Pedigo and T. Buthelezi*, J.Photobiol. and Photochem. Chem, 17,2005, 113.