Angel E. Kaifer

Professor

Phone:
(305) 284-4036
Locator Code:
0431

 
Career

Education

1984-85Post Doctoral University of Texas
1984Ph.D. University of Puerto Rico
Research

Our group's research interests focus on the general area of Supramolecular Electrochemistry.  For more than twenty years we have been investigating the electrochemical properties of a number of supramolecular systems, from host-guest complexes to self-assembled monolayers and dendrimers.  In particular, we have been especially interested in the idea of using redox conversions to control the structure of supramolecular assemblies.  This possibility is very relevant to the design of molecular devices.  We are also interested on the effects that supramolecular structure may exert on the kinetics and thermodynamics of electron transfer reactions.  Illustrative examples of specific systems in which we are currently exploring these general ideas are:

Cucurbit[n]uril Complexes:  The cucurbit[n]uril (CB) hosts constitute a fascinating family of molecular containers with outstanding binding affinity and selectivity.  We are developing mechanisms to switch and control the binding ability of CB hosts on demand.  We have recently discovered that CB hosts can be used to control the extent of aggregation of dyes and porphyrins in aqueous media.  We are particularly interested in the development of analytical applications based on the controlled formation of highly fluorescent J-aggregates.

Molecular Capsules:  The electrochemical properties of encapsulated redox active centers are unusual and attractive because little is known on the properties and reactivity of encapsulated molecules.  Our efforts in this area are geared to understand electron transfer processes involving species trapped inside molecular capsules of variable sizes. 

Functionalized Dendrimers: We still continue our long-standing research effort on the properties of redox active and fluorescent dendrimers.  We are also working on dendrimer functionalization to facilitate effective DNA delivery to cells.

Graduate students in our research group learn to use physical/analytical techniques (mainly electrochemical and spectroscopic) for the characterization of molecular structures, supramolecular assemblies and binding interactions.  Many students in the group also have an opportunity to gain significant expertise in preparative organic chemistry.

LIST OF SPECIALTIES: Electrochemistry, supramolecular chemistry, functionalized dendrimers

Publications

Kaifer, A. Portal Effects on the Stability of Cucurbituril Complexes 244-24958,3 (Israel Journal of Chemistry. 2018). [Link]

SUMMARY: This work is concerned with the properties of cucurbit[n]uril (CBn) host portals. The carbonyl oxygens lining each of the cavity openings on these hosts give rise to a rim of negative charge density, which often has strong effects on guest binding processes. The negative effect that carboxylates exert on guest binding to cucurbit[7]uril (CB7) is described in detail, as well as the fact that the protonation state of terminal −COO/COOH groups can be utilized to control CB7 shuttling on suitably designed pseudorotaxanes. Carboxylates can also slow down the kinetics of CB7 complex formation and dissociation. Finally, the electrostatic properties of the portals are useful ‐with suitable molecular design‐ to develop strong cooperativity effects, resulting from attractive side‐by‐side interactions, on the assembly of multi‐component supramolecular complexes.

Dong, N., He, J., Li, T., Peralta, A., Avei, M. R., Ma, M. & Kaifer, A. Synthesis and Binding Properties of Monohydroxy-cucurbit[7]uril: A Key Derivative for the Functionalization of Cu-curbituril Hosts 5467–547383 (10) (J. Org. Chem.,. 2018). [Link]


Zilio, S., Vella, J. L., De La Fuente, A. C., Daftarian, P. M., Weed, D., Kaifer, A., Marigo, I., Leone, K., Bronte, V. & Serafini, P., 4PD functionalized dendrimers: A flexible tool for in vivo gene silencing of tumor-educated myeloid cells 4166-4177198, 10 (Journal of Immunology. 2017). [Link]


Iglesias, V., Avei, M. R., Bruña, S., Cuadrado, I. & Kaifer, A., Binding Interactions between a Ferrocenylguanidinium Guest and Cucurbit[n]uril Hosts 415-41982, 1 (Journal of Organic Chemistry. 2017). [Link]


Sleziakova, K., Avei, M. R., Kaifer, A. & Sindelar, V. Binding of bambusuril with bipyridinium guests in water 832-837 (Supramolecular Chemistry. 2017). [Link]

SUMMARY: Bambusurils are a family of receptor molecules related to the cucurbit[n]urils and appreciated for their high affinities to inorganic anions. Here we show that a bambusuril macrocycle bearing carboxylate functional groups on its portals can form external complexes with bipyridinium cationic guests in aqueous solution. The apparent binding affinities of the complex can be modulated by the addition of potassium cations, which compete with the guests for the carboxylate portals of the macrocycle. We further illustrate that the binding mode of these host-guest systems varies depending on the choice of bipyridinium guests.

Moutsiopoulou, A., Hunt, E., Broyles, D., Pereira, C. A., Woodward, K., Dikici, E., Kaifer, A., Daunert, S. & Deo, S. K., Bioorthogonal Protein Conjugation: Application to the Development of a Highly Sensitive Bioluminescent Immunoassay for the Detection of Interferon-γ 1749-175728, 6 (Bioconjugate Chemistry. 2017). [Link]


Kaifer, A. Electrochemical properties of cucurbit[7]uril complexes of ferrocenyl derivatives 77-81468 (Inorganica Chimica Acta.. 2017). [Link]


Kaifer, A. Luis Echegoyen - Trailblazer in physical organic chemistry 1-2468 (Inorganica Chimica Acta.. 2017). [Link]


Mikulu, L., Michalicova, R., Iglesias, V., Yawer, M. A., Kaifer, A., Lubal, P. & Sindelar, V. pH Control on the Sequential Uptake and Release of Organic Cations by Cucurbit[7]uril 2350-235523 (Chemistry - A European Journal. 2017). [Link]


Avei, M. R. & Kaifer, A. Through-Space Communication Effects on the Electrochemical Reduction of Partially Oxidized Pillar[5]arenes Containing Variable Numbers of Quinone Units 8590-859782, 16 (Journal of Organic Chemistry. 2017). [Link]