Synthetic hosts by monomolecular imprinting inside dendrimers.
Synthetic host systems capable of selectively binding guest molecules are of interest for applications ranging from separations and chemical or biological sensing to the development of biomedical materials. Such host systems can be efficiently prepared by 'imprinting' polymers or inorganic materials with template molecules, which, upon removal, leave behind spatially arranged functional groups that act as recognition sites. However, molecularly imprinted polymers have limitations, including incomplete template removal, broad guest affinities and selectivities, and slow mass transfer. An alternative strategy for moulding desired recognition sites uses combinatorial libraries of assemblies that are made of a relatively small number of molecules, interconverting in dynamic equilibrium; upon addition of a target molecule, the library equilibrium shifts towards the best hosts. Here we describe the dynamic imprinting of dendritic macromolecules with porphyrin templates to yield synthetic host molecules containing one binding site each. The process is based on our general strategy to prepare cored dendrimers, and involves covalent attachment of dendrons to a porphyrin core, cross-linking of the end-groups of the dendrons, and removal of the porphyrin template by hydrolysis. In contrast to more traditional polymer imprinting, our approach ensures nearly homogeneous binding sites and quantitative template removal. Moreover, the hosts are soluble in common organic solvents and amenable to the incorporation of other functional groups, which should facilitate further development of this system for novel applications.
Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, USA. sczimmer@uiuc.edu
Steven C
SC
Zimmerman
Michael S
MS
Wendland
Neal A
NA
Rakow
Ilya
I
Zharov
Kenneth S
KS
Suslick
D001554:Benzene / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D003432:Cross-Linking Reagents / Q000378:metabolism; D005663:Furans / Q000378:metabolism; D006860:Hydrogen Bonding; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D015335:Molecular Probes / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D015394:Molecular Structure; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D011166:Porphyrins / Q000737:chemistry / Q000378:metabolism*; D012995:Solubility; D012997:Solvents / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity; D013698:Templates, Genetic; D013816:Thermodynamics
D003432:Cross-Linking Reagents; D005663:Furans; D046911:Macromolecular Substances; D015335:Molecular Probes; D011108:Polymers; D011166:Porphyrins; D012997:Solvents; C018674:tetrahydrofuran; D001554:Benzene