Fe(P)(NO), where P = TPP, TPC, or OEP, is reduced in three one-electron steps in nonaqueous solvents. The products of the first two waves (Fe(P)(NO)" and Fe(P)(NO)2") were stable, and the visible spectra were obtained by using OTTLE spectroelectrochemistry. The vibrational spectra of Fe(P)(NO) and its first reduction product obtained coulometrically were recorded. The porphyrin vibrations for both species were consistent with low-spin ferrous complexes. The vno and vfc-n bands could also be observed for both complexes, though i>n0 for Fe(TPP)(NO)" was quite weak. For Fe(TPP)(NO), vN0 (15N values in parentheses) was 1681 cm"1 (1647 cm"1) and vFe_N was 525 cm"1 (517 cm"1). Upon reduction, vN0 decreased to 1496 cm"1 (1475 cm"1) while vFe-N increased to 549 cm"1 (538 cm"1). These results were consistent with the addition of the electron to the half-filled d,2 + orbital, which is formed from * 0 and iron dz2 orbitals. Therefore, addition of an electron to this orbital would lead to a strengthening of the Fe-N bond and a weakening of the N-O bond. Dc polarography of Fe(TPP)(NO) and Fe(TPC)(NO) was carried out in the presence of several substituted phenols. The limiting current and half-wave potential of the first wave were unaffected by the presence of the phenols, except at high phenol concentrations. A new second wave appeared, though, in the presence of phenols, and the limiting current and half-wave potential for this wave depended strongly on the concentration and identity of the weak acid. The overall reduction appeared to involve three electrons on the polarographic time scale, to yield Fe(P)" and hydroxylamine. Further reduction to ammonia was observed on the coulometric time scale. Exhaustive electrolysis gave ammonia in nearly quantitative yield for 2-chlorophenol concentrations greater than 20 mM. No differences were observed in the polarographic behavior of Fe(TPP)(NO) and Fe(TPC)(NO), but somewhat higher concentrations of 2-chlorophenol were needed to generate ammonia coulometrically.

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An LCD (Liquid Crystal Display) is a standard display device for hand-held embedded systems. Today, color TFT (Thin-Film Transistor) LCDs are common even in cost-effective equipments. An LCD display system is composed of an LCD panel, a frame buffer memory, an LCD and frame buffer controller, and a backlight inverter and lamp. All of them are heavy power consumers, and their portion becomes much more dominant when running interactive applications. This is because interactive applications are often triggered by human inputs and thus result in a lot of slack time in the CPU and memory system, which can be effectively used for dynamic power management.In this paper, we introduce low-power LCD display schemes as a system-level approach. We accurately characterize the energy consumption at the component level and minimize energy consumption of each component without appreciable display quality degradation. We develop several techniques such as variable-duty-ratio refresh, dynamic-color-depth control and backlight luminance dimming with brightness compensation or contrast enhancement. Each method exhibits power reduction of 260mW, 250mW and 480mW, respectively. The aggregate energy reduction ratio is 28% out of total energy consumption including the CPU and the main memory system when we execute a document viewer. We also demonstrate that we can extend the battery life about 38% and 20% for a text editor and an MPEG4 player, respectively.

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