Capacious Deep-Cavity Cavitand/Hydrophobic Guest Assemblies with Tunable Interior Volumes

Tulane University, New Orleans LA

Investigators

Abstract

PI: Ashbaugh, Henry Proposal Number: 1403167 Institution: Tulane University Title: Capacious Deep-Cavity Cavitand/Hydrophobic Guest Assemblies with Tunable Interior Volumes The hydrophobic effect (the tendency of nonpolar molecules to separate from water) affects many different fields: the pharmaceutical industry (formulation and drug affinity), life sciences (proteins and macromolecular structures), material sciences (properties of polymers, emulsions, and liposomes), and indeed any chemical engineering or chemical application involving aqueous solutions (e.g., natural gas liquid separations and reactions in aqueous solution). This collaborative proposal aims to advance foundational knowledge of the hydrophobic assembly of cavitands (molecular assemblies that contain a cavity for guest molecules) and quantify the various factors governing their assembly and stability. Achieving the goals of this project will provide valuable information to exploit the class of dimeric, tetrameric, and hexameric assemblies in a range of potential technological applications, such as drug delivery vehicles, using either direct drug encapsulation or entrapment within cavitand/polymer networks. In addition, graduate and undergraduates will gain valuable training in both simulation techniques and experimental experience. The PIs will also incorporate the results of their research into a public service course. Simulations will be carried out in the Ashbaugh lab to characterize the structures of cavitand/guest assemblies in solution in molecular detail, quantify the thermodynamic driving forces for capsular assembly, and determine the guest binding free energies that drive complex structural transitions with increasing guest size. Experiments will be carried out in the Gibb lab to synthesize cavitands with varying chemical functionalities and pocket sizes, determine the binding affinities of alkyl guests within the cavitand complexes, and characterize the aggregation state of the complex and conformational motifs of confined guests. These tasks will enable the investigators to determine the influence of alkane host size, cavitand chemical structure, and solution conditions on the aggregation state of the cavitand assembly, as well as enable them to determine the molecular structures associated with cavitand assembly.