| Attributs | Valeurs |
|---|
| type
| |
| Is Part Of
| |
| Subject
| |
| Title
| - Partial Stacking of a Water-Soluble Porphyrin in ComplexMonolayers with Insoluble Lipid
|
| has manifestation of work
| |
| related by
| |
| Author
| |
| Abstract
| - Mixed monolayers of a water-soluble tetracationic porphyrin(TMPyP) and an insoluble lipid matrixwith anionic head groups (DMPA) were formed by the cospreading method.A ratio TMPyP:DMPA = 1:4was selected by investigation of π−area isotherms and stability ofthe cospread monolayer. Reflectionspectroscopy has been used to infer the molecular organization of theporphyrin molecules in the complexmonolayer at the air−water interface. A blue shift in the Soretband was observed with increasing surfacepressure. The mixed monolayer of TMPyP:DMPA = 1:4 wastransferred onto a glass substrate, and themolecular organization of the porphyrin was studied by transmissionspectroscopy with plane polarizedlight (s and p) under various angles of incidence. The analysis ofthe reflection spectra at the air−waterinterface and absorption spectrum of the mixed monolayer on glass leadsto a model of partial stackingof the porphyrin molecules in the monolayer at the air−waterinterface when the surface pressure isincreased. On the glass substrate, the TMPyP molecules attached toDMPA are monomeric. Further,indirect evidence for the partial stacking model in the case of themixture TMPyP:DMPA = 1:4 wasobtained from the investigation of the mixed monolayer TMPyP:DMPA:PME= 1:4:16 (PME, methylpalmitate) at the air−water interface and transferred on glass.The presence of the neutral lipid moleculesfacilitates dense packing of the insoluble monolayer matrix and thematching of surface charge densitiesof the matrix and the porphyrin moiety. In this way, theintermolecular interactions between porphyrinmolecules at the air−water interface under high surface pressure arereduced and the stacking is avoided.
|
| article type
| |
| is part of this journal
| |
