Langmuir−Blodgett Films of Stearic Acid Containing Octakis((methoxycarbonyl)methyl)-meso- tetrakis(((eicosanyloxy)carbonyl)phenyl)porphyrin

Molecular mechanics calculations are coupled with a knowledge of properties of porphyrins in solution and available synthetic strategies to computer-designed a lipoporphyrin, [2,3,7,8,12,13,17,18-octakis((methoxycarbonyl)methyl)-5,10,15,20-tetrakis(((eicosanyloxy)carbonyl)phenyl)porphyrin] (LipoP), for future electron-transfer studies and biosensor applications. To prevent separation of the porphyrin and stearic acid phases in the films, the head group was chosen on the basis of earlier studies that showed that its nickel(II) derivative does not π−π aggregate in aqueous solution. The lack of aggregation of the porphyrin unit results from the high degree of nonplanarity of the macrocycle and the steric constraints of the twelve bulky peripheral acid substituents. Nonpolar tails consisting of 20-carbon long linear alkanes were attached to the head group to anchor the LipoP head group into the stearic acid films. Metal derivatives of LipoP have been synthesized and characterized by NMR, resonance Raman, and ...