Alejandro O. Cuello

Education:

Ph.D. University of Massachusetts, MA; 1995-

M.S., University of Puerto Rico, Mayaguez, PR, 1995

B.S., (Organic and Analytical Chemistry) National University of Cordoba, Cordoba, Argentina, 1986

Research Interests:

Computational chemistry, organic electrochemistry, molecular recognition, EPR spectroscopy

Current Research

It is known that introducing different substituents on the isoalloxazine ring of the flavin changes its redox behavior. We wanted to explore the influence of N(3) substitution on the redox characteristics of flavins. Although N(3)-methyl and N(3)-ethyl flavins can be obtained by a simple SN2 reaction, this approach restricts the N(3) substitution to primary carbon alkylation. To overcome this limitation, we developed another strategy based on the Mitsunobu reaction1 . This approach allows us to introduce a larger variety of primary and secondary substituents at the N(3) position. The redox potential data obtained by CV (cyclic voltammetry) on different N(3) substituted flavins indicates that the substituent changes the redox properties of flavins via two different effects: electronic and steric. A different set of substitutions at the N(3) position will be done to explore the influence of field effect (through space electronic interaction). We also observed that the solvent used for running the CV is an important factor in the measurement of the redox properties. Preliminary results indicates that N(3) substitution has only a minor effect on the redox properties of flavins in solvents with high ability to form hydrogen bonding. This suggests that the activity of flavoenzymes can be regulated by the protein itself, changing the environment in which the flavin is immersed. Different levels of calculations (AM1, HF, B3LYP, etc.) with and without solvent effects are being run to observe the effect of the solvent interaction on the electronic densities and energies of substituted flavins.

Publications:

"Communication of Electronic Information over Extended Distances. An Experimental and Density Functional Investigation" R. Deans, A. Cuello, T. Galow, M. Ober and V. Rotello, J. Chem. Soc. Perkin Trans., submitted for publication.

"Electronic Communication in Structurally Constrained Cyclopenta-Fused Polyaromatics. An Experimental and Density Functional Investigation" A. Niemz, L. Steffen, B. Plummer, A. Cuello, V. Rotello, J. Am. Chem. Soc., in press.

"Model Systems for Flavoenzyme Activity. The Role of N(3)-H Hydrogen Bonding in Flavin Redox Processes" A. Cuello, C. McIntosh, V. Rotello, J. Am. Chem. Soc., in press.

"The Plausible Aromaticity of 1,8 Naphthalimides: The Enthalpy of Formation of N-Methyl-1-8 Naphthalimide" M. Roux, P. Jimenez, J. Davalos, M. Martin-Luengo, V. Rotello, A. Cuello, J. Liebman, J. Struct Chem. in press.

"4-Ethoxycarbonyl-4'5,5'trimethyltetrathiafulvene: Langmuir-Blodgett Film Studies, ESR Spectra and the X-Ray Crystal Structure of (Me3TTFCO2Et)2.TCNQ Complex" M. Bryce, A. Moore, A. Batsanov, J. Howard, M. Petty, L. Goldenberg, G. Williams, A. Cuello, V. Rotello, J. Mater. Chem., 1999, 9, 2973-2978.

"Synthesis and Intramolecular Charge-Transfer Properties of New Tetrathiafulvalene-s-Tetracyanoanthraquinodimethane Diad (TTF-s-TCNAQ) and Triad (TTF-s-TCNAQ-s-TTF Molecules)", P. Miguel, M. Bryce, L. Goldenberg, A. Beeby, V. Khodorkovsky, L. Shaipiro, A., Niemz, A., Cuello, V. Rotello, J. Mater. Chem., 1998, 71-77.

"Model Systems for Flavoenzyme Activity. A Versatile Synthesis of N(3) Alkylated Flavins" J. Dutra, A. Cuello, V. Rotello, Tetrahedron Lett., 1997, 4003-4006.

Presentations:

1998: "Redox Control of Recognition Processes", 216th National Meeting of the American Chemical Society, Boston, MA August, 1998.

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