| The porphyrazines (pzs), a class of porphyrin derivatives, have shown potential as therapeutic and imaging agents due to a combination of their near-IR absorbance/fluorescence and their enhanced chemical flexibility. Cell viability/proliferation assays and fluorescence microscopy were carried out in both tumor and normal cells to characterize the biological activity of the pzs. Suites of structurally similar compounds, including ones with varying amphiphilicity and ones with different biological vectors are studied in order to develop structure-function relationships for the biological activity of pzs. The overall biological activity found for these compounds suggests that, as a class, these pzs offer tremendous potential as clinically-relevant diagnostic and therapeutic agents.; The preparation of novel pzs designed for attachment to surfaces is also presented. A series of multithiol-functionalized freebase and Zn pzs have been prepared and characterized as self-assembled monolayers (SAMs) on Au. The reduction potentials of the pzs were studied as a function of the film thickness using the angle-resolved X-ray photoelectron spectroscopy and the cyclic voltammetry. We found that pzs provide a unique opportunity to control electronic and chemical characteristics for such applications through heteroatom functionalization, while at the same time allowing us to control the mode of surface attachment. All pzs show large shifts in potential upon surface binding, with the magnitude of the shift depending on the proximity/orientation of the pz to the surface. These observed effects can be explained by image-charge energetics, which qualitatively explains our results and which indicates that quantitative studies of the fundamental thermodynamic aspects of heterogeneous electron transfer in this system will be very fruitful. |
