Synthesis of organic compounds for two-photon initiated polymerization and molecular recognition
In section I, three-dimensional polymeric objects were fabricated using two-photon initiated polymerization (TPIP) with a two-photon absorbing chromophore and an acrylate resin. The feasibility of fabricating polymeric features on the nanoscale was explored using an enhanced field generated at the apex of a gold tip as the excitation source, as used in near-field excitation (NFE). In section II, C3-symmetric chiral receptors were used to direct enantioselective enolate alkylation. A series of host compounds was synthesized and 1:1 host to enolate binding was observed by 1 H NMR titration experiments. A moderate increase in the enantioselectivity of the alkylation of 2-acetylcyclohexanone was observed in the presence of host 2.22. Also in section II, the use of enolate stabilization via charge-pairing was investigated for the reduction of the pKa of 2- acetylcyclopentanone. In the presence of host 3.12, the pKa of 2- acetylcyclopentanone was reduced by 10 pKa units. In comparison with the 2.9 pKa unit shift observed with host 3.11, this result suggests that charge-pairing is more effective in stabilizing enolates in enzyme active sites than traditional hydrogen bonding.