A Compact All-Carbon Tripodal Tether Affords High Coverage of Porphyrins on Silicon Surfaces
摘要:
Redox-active molecules designed to give high charge density on electroactive surfaces are essential for applications in molecular information storage. To achieve a small molecular footprint and thereby high surface charge density, a compound consisting of a triallyl tripod attached via a p-phenylene unit to a porphyrin (1) has been synthesized. The zinc chelate of 1 (Zn-1) was attached to Si(100). Electrochemical measurements indicate that the molecular footprint (75 A) in the monolayer is only similar to 50% larger than the minimum achievable, indicating high surface coverage. IR spectroscopy indicates that the bands due to the nu(C=C) (1638 cm(-1)) and gamma(CH) (915 cm-1) vibrations present in the solid sample (KBr pellet) are absent from the spectra of the monolayers of Zn-1, consistent with saturation of the double bond in each of the three legs of the tripod upon the hydrosilylation process accompanying attachment. Comparison of the relative intensities of the in-plane (998 cm-1) versus out-of-plane (797 cm-1) porphyrin modes indicates the average tilt angle (a) of the porphyrin ring with respect to the surface normal is similar to 46 degrees, a value also observed for analogous porphyrins tethered to Si(100) via monopodal carbon linkers. Accordingly, the higher packing densities afforded by the compact tripodal linker are not due to a more upright orientation on the surface. The charge-retention half-lives (t(1/2)) for the first oxidation state of the Zn-1 monolayers increase from 10 to 50 s at low surface coverage (1-5 x 10(-11) mol(.)cm(-2)) to near 200 s at saturation coverage (similar to 2 x 10(-10) mol(.)cm(-2)). Taken together, the high surface charge density (despite the lack of upright orientation) of the triallyl-tripodal porphyrin makes this construct a viable candidate for molecular information storage applications.
Substituted benzazoloporphyrazines for polymerization and surface attachment and articles formed therefrom
申请人:Youngblood W. Justin
公开号:US20110015388A1
公开(公告)日:2011-01-20
The present invention provides an article of manufacture formed from a substrate and a benzazoloporphyrazine bound to the substrate. The article may take a variety of different forms and may be for example an electrochromic display, a molecular capacitor, a battery, a solar cell, or a molecular memory device. Methods of making such articles, along with compounds, methods and intermediates useful for making such benzazoloporphyrazines, are also described.
SUBSTITUTED BENZAZOLOPORPHYRAZINES FOR POLYMERIZATION AND SURFACE ATTACHMENT AND ARTICLES FORMED THEREFROM
申请人:Youngblood W. Justin
公开号:US20120101243A1
公开(公告)日:2012-04-26
The present invention provides an article of manufacture formed from a substrate and a benzazoloporphyrazine bound to the substrate. The article may take a variety of different forms and may be for example an electrochromic display, a molecular capacitor, a battery, a solar cell, or a molecular memory device. Methods of making such articles, along with compounds, methods and intermediates useful for making such benzazoloporphyrazines, are also described.