ORGN 111 |
| In this paper we will report small synthetic photo-driven molecular motors individually capable of directly converting chemical energy into mechanical work. The molecular motors are based on the photoisomerizable actuator, biindanylidene (biin) covalently connected to various molecular loads, including disulfide fragments, cyclobutene, etc, via difference linkers. Upon irradiation of the complex at 365 nm, isomerization of biin from cis to trans results in mechanical force of up to 1 nN applied on the substrate. This force leads to mechanochemical acceleration of substrate reactions, such as electrocyclic ring opening, disulfide/thiolate exchange, etc. Several routes to cis-biin/substrate complexes have been developed, starting with commercially available 6-hydroxyindanone. One strategy involves an initial assembly of the biin fragment by McMurry coupling followed by macrocyclic addition of the substrate. The other method relies on the synthesis of substrates modified at two properly selected points with 6-(Br(CH2)nO)indanone groups. Macrocyclization by McMurry coupling yields the actuator/substrate complex. Depending on the length of the linkers connecting the biin actuator and the substrate fragment, the lifetime of the trans-biin/substrate complex at room temperature varies between minutes and months, enabling us to correlate the degree of rate acceleration of the substrate fragment and the magnitude of mechanical force transduced from the biin actuator to the substrate. |
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Process R&D, Physical Organic Chemistry, Heterocycles, Aromatics, Metal-Mediated Reactions
8:00 PM-10:00 PM, Sunday, March 25, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Sci-Mix
Division of Organic Chemistry |