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Microfibrous self-aggregation of chromophoric groups of porphyrin and/or pyrene substituted by didodecyl L-glutamic acid in organic media is confirmed by transmission electron microscopic (TEM) observation. Chromophoric probes of porphyrin and pyrene moieties enable evaluation of their assembling behavior photophysically through UV-vis, circular dichroism (CD), and fluorescence spectroscopic characterization. This spectroscopic characterization was able to compensate the lack of TEM observation for the aggregation even at a low concentration below the critical gel concentration. The temperature affects the salient features of the photophysics of porphyrin or pyrene in the microfibrous assemblies. Highly oriented network structures were formed at low temperature since the CD intensities of the porphyrin and pyrene systems increased with lowering the temperature. Fluorescence spectroscopic characterization confirmed the monomer excitation of porphyrin itself, and efficient excimer formation for the pyrene-pyrene charge transfer was detected at low temperature. In particular, we also obtained the preliminary results of fluorescence spectroscopic measurement on singlet-singlet energy migration from pyrene to porphyrin in the mixed assemblies for mimicry of the efficient energy transfer process of the photosynthetic antenna complex.

The properties of a new class of chiral, room-temperature, ionic liquids (RTILs) are described. They are made from easily synthesized, readily available materials and can be transformed reversibly to their nonionic liquid states. The nonionic liquids consist of neat equimolar mixtures of a N′-alkyl-N,Ndimethylacetamidine (L) and an alkyl ester of a naturally occurring amino acid (n). When exposed to 1 atm of CO 2 gas, the L/n solutions become cationic-anionic pairs, amidinium carbamates. Of the 50 L/n combinations examined, all except those involving the methyl ester of tyrosine (which was immiscible with the amidines) form RTIL states under CO 2 atmospheres, and several remain liquids to at least -18 °C. Heating the ionic liquids in air at ca. 50 °C or bubbling N 2 gas through them at ambient temperatures for protracted periods displaces the CO 2 and re-establishes the nonionic L/n states. As an example of the changes effected by cycling between the two liquid states, a spectroscopic probe, 1-(pdimethylaminophenyl)-2-nitroethylene, senses a polarity like that of toluene before a mixture of N′octyl-N,N-dimethylacetamidine/isoleucine methyl ester is exposed to CO 2 and a polarity like that of N,Ndimethylformamide afterward; whereas a low-polarity solvent, decane, is solublized readily by the nonionic L/n mixture, it is immiscible with the RTIL. Thermal and spectroscopic properties of both the nonionic and ionic phases are reported and compared. Several possible applications for these RTILs can be envisioned because, unlike many other ionic liquids, these need not be prepared and handled under scrupulously dry conditions and they can be cycled repeatedly between high-and low-polarity states.

Variation in stable nitrogen isotope ratios (δ15N) was assessed for plants comprising two wetland communities, a bog‐fen system and a flood plain, in central Japan. δ15N of 12 species from the bog‐fen system and six species from the flood plain were remarkably variable, ranging from −5.9 to +1.1‰ and from +3.1 to +8.7‰, respectively. Phragmites australis exhibited the highest δ15N value at both sites. Rooting depth also differed greatly with plant species, ranging from 5 cm to over 200 cm in the bog‐fen system. There was a tendency for plants having deeper root systems to exhibit higher δ15N values; plant δ15N was positively associated with rooting depth. Moreover, an increasing gradient of peat δ15N was found along with depth. This evidence, together with the fact that inorganic nitrogen was depleted under a deep‐rooted Phragmites australis stand, strongly suggests that deep‐rooted plants actually absorb nitrogen from the deep peat layer. Thus, we successfully demonstrated the diverse traits of nitrogen nutrition among mire plants using stable isotope analysis. The ecological significance of deep rooting in mire plants is that it enables those plants to monopolize nutrients in deep substratum layers. This advantage should compensate for any consequential structural and/or physiological costs. Good evidence of the benefits of deep rooting is provided by the fact that Phragmites australis dominates as a tall mire grass.

The properties of reversible, room-temperature, chiral, ionic liquids (L-A-C) are reported. They are easily prepared by passing CO2 gas through equimolar mixtures of a simple amidine (L) and a chiral amino alcohol (A), L/A, derived from a naturally occurring amino acid, and they can be returned to their L/A states by passing a displacing gas, N2, through the ionic liquid; the process of passing from uncharged to charged states can be repeated several times without discernible degradation of each phase. All of the 40 L/A combinations examined form room-temperature ionic liquids (most to ca. 50 °C under 1 atm of CO2) and they remain liquids to at least −20 °C. The L-A-C phases are more viscous than their corresponding L/A phases, the conductivities are much higher in the L-A-C phases than in the L/A phases, and the solubility characteristics of the liquids can be modulated significantly by exposing them to either CO2 or N2 gas. The spectroscopic characteristics of the L/A and L-A-C phases have been compared also. Their reversibility, chirality, broad temperature ranges, tolerance to water, and ease of preparation should make the combination of L/A and L-A-C phases useful as solvents for several “green” applications.

Aggregation structures in organic gels and xerogels formed from l-glutamic acid-derived lipids were investigated by scanning and transmission electron microscopies, X-ray analyses, and 1 H NMR and IR spectroscopic methods. These analyses showed that the gels were produced through the formation of highly oriented aggregates based on a single layer and a remarkable development of their ® brous morphology. We also describe how the critical aggregation concentration can be observed at a concentration below the critical gel concentration by using a dye-complexation method with a cyanine dye, NK-77.