Angel Kaifer

Ph.D., University of Puerto Rico, 1984
Postdoctorate, University of Texas, 1984-85

E-mail: akaifer@miami.edu

Research in a Nugget

Brief description of research

Publications 2004-Present

Link to our laboratory website: Kaifer Group


Research in a Nugget


Brief description of 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.


Publications 2004-Present

2008

Cui, L.; Gadde, S.; Shukla, A. D.; Sun, H.; Mague, J. T.; Kaifer, A. E. “Dimerization of Aromatic Ureido Pyrimidinedione Derivatives: Observation of an Unexpected Tautomer in the Solid State”, Chem. Commun. 2008, 1446-1448.

Liu, S.; Shukla, A. D.; Gadde, S.; Wagner, B. D.; Kaifer, A. E.; Isaacs, L. “Ternary Complexes Comprising Cucurbit[10]uril, Porphyrins and Guests”, Angew. Chem. Int. Ed2008, 47, 2657-2660.

Podkoscielny, D.; Philip, I.; Gibb, C. L. D.; Gibb, B.; Kaifer, A. E. “Encapsulation of Ferrocene and Peripheral Electrostatic Attachment of Viologens to Dimeric Molecular Capsules Formed by an Octaacid, Deep-Cavity Cavitand”, Chem. Eur. J.2008, 14, 4704-4710.

Podkoscielny, D.; Hooley, R. J.; Rebek, J.; Kaifer, A. E. “Ferrocene Derivatives Included in a Water-Soluble Host:  Are They electroactive?”, Org. Lett. 200810, 2865-2868.

Bhattacharya, P.; Kaifer. A. E. “Preparation, Characterization and Electrochemical Properties of a New Series of Hybrid Dendrimers Containing a Viologen Core, Fréchet and Newkome Dendrimers”, J. Org. Chem200873, 5693-5698 (FEATURED ARTICLE).

Berbeci, L. S.; Wang, W.; Kaifer, A. E. “Drastically Decreased Reactivity of Thiols and Disulfides Complexes by Cucurbit[6]uril“, Org. Lett. 200810, 3721-3724.

Xu, D.; Wang, W.; Gesua, D.; Kaifer, A. E. “A New Series of Dendrimers Containing Two Ferrocenyl Units and a Fréchet Dendron around a Triazine Nucleus”, Org. Lett200810, 4517-4520.

Gadde, S.; Batchelor, E. K.; Weiss, J. P.; Ling, Y.; Kaifer, A. E. “Control of H- and J-Aggregate Formation via Host-Guest Complexation using Cucurbituril Hosts”, J. Am. Chem. Soc. 2008130, 17114-17119.

2007

Ling, Y.; Wang, W.; Kaifer, A. E. “A New Cucurbit[8]uril-Based Fluorescent Receptor for Indole Derivatives”, Chem. Commun. 2007, 610-612.

Moon, M.; Philip, I.; Sun, H.; Kaifer, A. E. “Electrochemistry of Hydrogen-Bonded Systems”, J. Solid State Electrochem2007, 11, 1635-1641.

Sindelar, V.; Silvi, S.; Parker, S. E.; Sobransingh, D.; Kaifer, A. E. “Proton and Electron Transfer Control on the Position of Cucurbit[n]uril Wheels in Stable Pseudorotaxanes”, Adv. Funct. Mater. 200717, 694-701 (FEATURE ARTICLE).

Sindelar, V.; Parker, S. E.; Kaifer, A. E. “Inclusion of Anthraquinone Derivatives By the Cucurbit[7]uril Host”, New. J. Chem. 200731, 725-728.

Brunet, E.; Alonso, M.; Cerro, C.; Juanes, O.; Rodríguez-Ubis, J. C.; Kaifer, A. E. “Luminescence and Electrochemical Study of the Photoinduced Electron Transfer within the Layers of Zirconium Phosphate”, Adv. Funct. Mater. 200717, 1603-1610.

Wang, W.; Sun, H.; Kaifer, A. E. “Redox Active, Hybrid Dendrimers Containing Fréchet- and Newkome-Type Blocks“, Org. Lett. 20079, 2657-2660.

Ling, Y.; Mague, J. T.; Kaifer, A. E. “Inclusion Complexation of Diquat and Paraquat by the Hosts Cucurbit[7]uril and Cucurbit[8]uril: A Study in Contrast”,Chem. Eur. J200713, 7908-7914.

Kaifer, A. E. “Electron Transfer and Molecular Recognition in Metallocene-Containing Dendrimers”, Eur. J. Inorg. Chem2007, 5015-5027. (Invited Microreview).

Rekharsky, M. V.; Mori, T.; Yang, C.; Ko, Y. H.; Selvapalam, N.; Kim, H.; Sobransingh, D.; Kaifer. A. E.; Liu, S.; Isaacs, L.; Chen, W.; Moghaddam, S.; Gilson, M. K.; Kim, K.; Inoue, Y. “A Synthetic Host-Guest System Achieves Avidin-Biotin Affinity by Overcoming Enthalpy-Entropy Compensation“, Proc. Natl. Acad. Sci. USA 2007104, 20737-20742.

2006

Sun, H.; Steeb, J.; Kaifer, A. E. “Efficient Electronic Communication between Two Identical Ferrocene Centers in a Hydrogen-Bonded Dimer”, J. Am. Chem. Soc.2006128, 2820-2821.

Sun, H.; Kaifer, A. E. “A Simple Method Based on NMR Spectroscopy and Ultramicroelectrode Voltammetry for the Determination of the Number of Electrons in a Faradaic Process”, Organometallics 200625, 1828-1830.

Sindelar, V.; Silvi, S.; Kaifer, A. E. “Switching a Molecular Shuttle On and Off: Simple, pH-Controlled Pseudorotaxanes Based on Cucurbit[7]uril”, Chem Commun.2006, 2185-2187.

Sobransingh, D.; Kaifer, A. E. “Electrochemically Switchable Cucurbit[7]util-Based Pseudorotaxanes”, Org. Lett. 20068, 3247-3250.

Sobransingh, D.; Kaifer, A. E. “New Dendrimers Containing a Single Cobaltocenium Unit Covalently Attached to the Apical Position of Newkome Dendrons: Electrochemistry and Guest Binding Interactions with Cucurbit[8]uril”, Langmuir 200622, 10540-10544.

Wang, W.; Kaifer, A. E. “Electrochemical Switching and Size Selection in Cucurbit[8]uril-Mediated Dendrimer Self-Assembly“, Angew. Chem. Int. Ed.200645, 7042-7046.

Ling, Y.; Kaifer, A. E. “Complexation of Poly(phenylenevinylene) and Some of Its Precursor Monomers by Cucurbituril Hosts”, Chem. Mater. 200618, 5944-5949.

2005

Ying, J.-W., Sobransingh, D.; Xu, G.-L.; Kaifer, A. E.; Ren, T. “Sulfide-Capped, Wire-Like Metallaynes as Connectors for Au Nanoparticle Assemblies”, Chem. Commun. 2005, 357-359.

Sindelar, V.; Cejas, M.; Raymo, F. M.; Kaifer, A. E. “Tight Inclusion Complexation of 2,7-Dimethyldiazapyrenium in cucurbit[7]uril”, New. J. Chem. 200529, 280-282.

Philip, I.; Kaifer, A. E. “Noncovalent Encapsulation of Cobaltocenium Inside Resorcinarene Molecular Capsules”, J. Org. Chem200570, 1558-1564.

Ong, W.; Grindstaff, J.; Sobransingh, D.; Toba, R.; Quintela, J. M.; Peinador, C.; Kaifer, A. E. “Electrochemical and Guest Binding Properties of Fréchet- and Newkome-Type Dendrimers with a Single Viologen Unit Located at Their Apical Positions”, J. Am. Chem. Soc2005127, 3353-3361.

Jeon, W. S.; Moon, K.; Park, S. H.; Chun, H.; Ko, Y. H.; Lee, J. Y.; Lee, E. S.; Samal, S.; Selvapalam, N.; Rekharsky, M. V.; Sindelar, V.; Sobransingh, D.; Inoue, Y.; Kaifer, A. E.; Kim, K. “Complexation of Ferrocene Derivatives by the Cucurbit[7]uril Host:  A Comparative Study of the Cucurbituril and Cyclodextrin Host Families”, J. Am. Chem. Soc. 2005127, 12984-12989.

Sun, H.; Kaifer, A. E. “Unsymmetric Dendrimers Containing a Single Ureidopyrimidine Unit: Generation-Dependent Dimerization”, Org. Lett. 20057, 3845-3848.

Sobransingh, D.; Kaifer, A. E. “Binding Interactions Between the Host Cucurbit[7]uril and Dendrimer Guests Containing a Single Ferrocenyl Residue”,Chem. Commun. 2005, 5071-5073.

Sindelar, V.; Cejas, M. A.; Raymo, F. M.; Chen, W.; Parker, S. E.; Kaifer, A. E. “Supramolecular Assembly of 2,7-Dimethyldiazapyrenium and Cucurbit[8]uril: A New Fluorescent Host for Detection of Catechol and Dopamine”, Chem. Eur. J.200511, 7054-7059.

2004

Mendoza, S.; Godinez, L. A.; Kaifer, A. E. “Tetrathiafulvalene-Functionalized Cavitands as Building Blocks for Redox Active Hemicarcerands”, Supramolecular Chem. 200416, 165-169.

Moon, K.; Kaifer, A. E. “Modes of Binding Interaction between Viologen Guests and the Cucubit[7]uril Host”, Org. Lett20046, 185-188.

Ong, W.; Kaifer, A. E. “Salt Effects on the Apparent Stability of the Cucurbit[7]uril-Methylviologen Inclusion Complex”, J. Org. Chem. 2004, 69, 1383-1385.

Pandey, S.; Redden, R. A.; Fletcher, K. A.; Sasaki, D. Y.; Kaifer, A. E.; Baker, G. A. “Generation and pH dependent superquenching of poly(amido) carboxylate dendrons hosting a single “focal point” pyrene”, Chem. Commun2004, 1318-1319.

Ong, W.; Gomez-Kaifer, M.; Kaifer, A. E. “Dendrimers as Guests in Molecular Recognition Phenomena”, Chem. Commun2004, 1677-1683 (FEATURE ARTICLE).

Sindelar, V.; Moon, K. Kaifer, A. E. “Binding Selectivity of Cucurbit[7[uril: Bis(pyridinium)-1,4-xylylene versus 4,4’-Bipyridinium Guest Sites”, Org. Lett.20046, 2665-2668.

Mendoza, S.; Castaño, E.; Meas, Y.; Godínez, L. A.; Kaifer, A. E. “Analysis of the Voltammetric Response of Electroactive Guests in the Presence of Non-Electroactive Hosts at Moderate Concentrations”, Electroanalysis 200416, 1469-1477.

Moon, K.; Grindstaff, J.; Sobransingh, D.; Kaifer, A. E. “Redox Controlled Self-Assembly of Viologen-Containing Dendrimers Mediated by Cucurbit[8]uril”,Angew. Chem. Int. Ed2004, 43, 5496-5499.

Moon, K.; Kaifer, A. E. “Dimeric Molecular Capsules Under Redox Control”, J. Am. Chem. Soc. 2004126, 15016-15017.