Monolayers porphyrins

Imahori H, Arimura M, Hanada T, et al. Photoactive three-dimensional monolayers porphyrin-alkanethiolate-stabilized gold clusters. J Am Chem Soc 2001 123 335-6. 

Hanada Y. Nishimura 1. Yamazaki Y. Sakata S. Fukuzumi, Photoactive Three-Dimensional Monolayers Porphyrin-Alkanethiolate-Stabilized Gold Clusters. J. Am. Chem. Soc. 2000,... 

Figure 6.6.7 Monolayer porphyrin leaflets in water made of 1. The leaflets are rolled...

Magnetic field effects on photoelectrochemical responses of modified electrodes with Langmuir-Blodgett monolayer containing porphyrin-viologen linked compounds. Mol. Cryst. Liq. Cryst., 294, 221-224. 

This research rests upon oxidative electrochemical polymerization (ECP) of solutions of the functionalized metallotetraphenylporphyrln monomers shown in Fig. 1. These oxidations lead to formation of thin, cross-linked polymeric films of the metallotetraphenylporphyrins on the electrode surface. The films contain from ca. 4 to 500 monolayer-equivalents of porphyrin sites, which are In high concentration (ca. 1M) since the polymer backbone consists solely of the porphyrins themselves as the backbone units. The polymeric films adhere to the electrode and... 

The ability, in a voltammetric experiment like Fig. 2B, to electrochemically charge the equivalent of many monolayers of porphyrin sites even though the individual sites are relatively immobile within the polymer, implies the existance of an efficient... 

Delmarre D., Meallet R., Bied-Charreton C., Pansu R., Heavy metal ions detection in solution, in sol-eel and with grafted porphyrin monolayers, J. Photochem. Photobiol. A 1999 124 23-28. 

As discussed in section 2.2, a mixture of AMP and AA showed two solid condensed phases above and below about 30 mN m- [5,10]. A loosely stacked structure of two porphyrins was proposed for LB films prepared at higher surface pressures than 30 mNmr1, which was caused by squeezing-out of a monomolecular structure formed at lower surface pressure [5,10]. In this section, photoelectric characteristics of LB films containing AMP and AA deposited at two solid condensed phases will be discussed in relation to multilayer structure and the anisotropic intermolecular tunneling rates [87]. Seven monolayers of 1 5 or 1 10 mixture of AMP and AA were deposited at 20 and 50 mN m-1 on an ITO plate at 18 °C to form stable Y-type LB films. Aluminum was vacuum evaporated onto LB films as sandwich-type electrodes at 10-6 Torr. Steady photocurrents were measured in a similar manner as mentioned above. 

SAMFETs have also been used in chemical sensing. The a-substituted quincpiethiophene SAMFETs were covered with a 10-nm pinhole-riddled iron tetraphenylporphyrin chloride layer, that acts as a receptor to nitric oxide (NO), an important biomarker [74]. The threshold voltage, measured by the FET transfer characteristics with the porphyrin receptor shifts upon increased exposure to NO. Annealing the monolayer FET in vacuum restores the initial FET behavior. Also, in the single monolayer HBC assembled FETs between metallic SWCNT source and drain electrodes increased current levels were measured in /d-Fds and Aj-Fg characteristics (Fig. 9) upon exposure to solutions of the electron acceptor TCNQ [68]. While the mechanism of response is not known, TCNQ has an affinity for coronene, and likely gives rise to charge transfer between electron-deficient TCNQ... 

Variations on the vertical dipping technique have been utilized to construct films containing divalent metal ions. For example, the quartz crystal microbalance (QCM) has been used to evaluate the horizontal lifting method of CdSt LB Film construction (26). In this method, the QCM quartz plate was touched to monolayers compressed on a subphase and lifted horizontally. Y-type transfer (transfer ratio of 1) was demonstrated with two centrosymmetric monolayers deposited for each cycle. A combination of the vertical and horizontal dipping techniques has been utilized to prepare multilayer films from an amphiphilic porphyrin compound (27). 

For formation of two porphyrin dye layers face-to-face on the support, the slide was simply dipped and then removed through the porphyrin film on the subphase. Deposition of surfactant porphyrins on the SnC OTE s for the photoelectric measurements was by vertical removal of the OTE (two slides at a time with the glass surfaces facing each other) through the porphyrin mixture on the aqueous subphase. Surfactant porphyrin (MT0APP) stearic acid octadecane monolayers in the ratio of 1 4 3 were held at a constant pressure of 25 dyne/cm for these depositions. 

Even 10 M porphyrin solution excitation spectra of these compounds show several additional bands in the Soret region due to intermolecular interactions. Also, the broadening and peak shifts are rather insensitive to dilution of the monolayers with SA, although fluorescence intensities do significantly decrease. 

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