Fluorogenic and chromogenic chemosensors and reagents for anions.

The increasing energy demand in the near future will force us to seek environmentally clean alternative energy resources. The emergence of nanomaterials as the new building blocks to construct light energy harvesting assemblies has opened up new ways to utilize renewable energy sources. This article discusses three major ways to utilize nanostructures for the design of solar energy conversion devices:  (i) Mimicking photosynthesis with donor−acceptor molecular assemblies or clusters, (ii) semiconductor assisted photocatalysis to produce fuels such as hydrogen, and (iii) nanostructure semiconductor based solar cells. This account further highlights some of the recent developments in these areas and points out the factors that limit the efficiency optimization. Strategies to employ ordered assemblies of semiconductor and metal nanoparticles, inorganic-organic hybrid assemblies, and carbon nanostructures in the energy conversion schemes are also discussed. Directing the future research efforts toward utiliza...

Meeting the Clean Energy Demand: Nanostructure Architectures for Solar Energy Conversion

This tutorial review focuses on the recent development of rhodamine derivatives, in which the spirolactam (non-fluorescent) to ring-opened amide (fluorescent) process was utilized.

A new trend in rhodamine-based chemosensors: application of spirolactam ring-opening to sensing ions

3.2. Thienothiophenes 1216 3.2.1. Thieno[3,4-b]thiophene Analogues 1216 3.2.2. Thieno[3,2-b]thiophene Analogues 1217 3.2.3. Thieno[2,3-b]thiophene Analogues 1218 3.3. , ′-Bridged Bithiophenes 1219 3.3.1. Dithienothiophene (DTT) Analogues 1220 3.3.2. Dithieno[3,2-b:2′3′-d]thiophene-4,4-dioxides 1221 3.3.3. Dithienosilole (DTS) Analogues 1221 3.3.4. Cyclopentadithiophene (CPDT) Analogues 1221 3.3.5. Nitrogen and Phosphor Atom Bridged Bithiophenes 1222

Functional oligothiophenes: molecular design for multidimensional nanoarchitectures and their applications.

Recently, the use of phosphorescent heavy-metal complexes as chemosensors has attracted increasing interest due to their advantageous photophysical properties. This critical review focuses on the design principles and the recent development of phosphorescent chemosensors for metal cations, anions, pH, oxygen, volatile organic compounds and biomolecules based on some heavy-metal complexes (such as Pt(II)-, Ru(II)-, Re(I)-, Ir(III)-, Cu(I)-, Au(I)- and Os(II)-based complexes), in which the variation in phosphorescence signals induced by the interaction between heavy-metal complexes and analytes is utilized (217 references).

Phosphorescent chemosensors based on heavy-metal complexes

Expanded porphyrins are synthetic analogues of the porphyrins, and differ from these and other naturally occurring tetrapyrrolic macrocycles by containing a larger central core with a minimum of 17 atoms, while retaining the extended conjugation features that are a hallmark of these quintessential biological pigments. The result of core expansion is to produce systems with novel spectral and electronic features, interesting and, often unprecedented, cation-coordination properties, and, in many cases, an ability to bind anions in certain protonation states. Also adding to the appeal of expanded porphyrins is their central role in addressing issues of aromaticity. In many cases, they also display structural features, such as decidedly nonplanar "figure-eight" motifs, that have no antecedents in the chemistry of porphyrins or related macrocyclic compounds. In this Review, the various synthetic approaches now being employed to produce expanded porphyrins as well as their various applications-related aspects are discussed.

Synthetic expanded porphyrin chemistry.

Expandierte Porphyrine sind synthetische Analoga der Porphyrine und unterscheiden sich von diesen und anderen naturlichen makrocyclischen Tetrapyrrolen durch einen groseren zentralen Ring mit mindestens 17 Atomen, wobei die ausgedehnte Konjugation erhalten bleibt, die die biologischen Pigmente kennzeichnet. Durch die Erweiterung des zentralen Rings entstehen Verbindungen mit neuen spektralen und elektronischen Merkmalen, ungewohnlichen Komplexbildungseigenschaften und in vielen Fallen der Eigenschaft, in bestimmten Protonierungszustanden Anionen zu binden. Zum Interesse an den expandierten Porphyrinen tragt auch ihre Schlusselrolle bei der Klarung von Fragen zur Aromatizitat bei. In vielen Fallen weisen sie in der Chemie der Porphyrine einmalige Strukturmerkmale auf, z. B. die nichtplanaren Figure-Eight-Konformationen. Dieser Aufsatz beschreibt schwerpunktmasig die heute verwendeten Syntheseverfahren fur expandierte Porphyrine und geht daneben auf spezielle Anwendungsaspekte ein.

Synthesechemie expandierter Porphyrine

Cyclo[8]pyrrole: A Simple-to-Make Expanded Porphyrin with No Meso Bridges

A strong correlation among calculated Nucleus-Independent Chemical Shift (NICS) values, molecular planarity, and the observed two-photon absorption (TPA) values was found for a series of closely matched expanded porphyrins. The expanded porphyrins in question consisted of [26]hexaphyrin, [28]hexaphyrin, rubyrin, amethyrin, cyclo[6]pyrrole, cyclo[7]pyrrole, and cyclo[8]pyrrole containing 22, 24, 26, 28, and 30 pi-electrons. Two of the systems, [28]hexaphyrin and amethyrin, were considered to be antiaromatic as judged from a simple application of Huckel's [4n + 2] rule. These systems displayed positive NICS(0) values (+43.5 and +17.1 ppm, respectively) and gave rise to TPA values of 2600 and 3100 GM, respectively. By contrast, a set of congeners containing 22, 26, and 30 pi-electrons (cyclo[n]pyrrole, n = 6, 7, and 8, respectively) were characterized by a linear correlation between the NICS and TPA values. In the case of the oligopyrrolic macrocycles containing 26 pi-electron systems, a further correlation between the molecular structure and various markers associated with aromaticity was seen. In particular, a decrease in the excited state lifetimes and an increase in the TPA values were seen as the flexibility of the systems increased. Based on the findings presented here, it is proposed that various readily measurable optical properties, including the two-photon absorption cross-section, can provide a quantitative experimental measure of aromaticity in macrocyclic pi-conjugated systems.

Nonlinear optical properties and excited-state dynamics of highly symmetric expanded porphyrins.

Applications of actinide chemistry, whether for energy or defense purposes, have left a legacy of potential waste hazards. The new expanded porphyrin ligand 1 forms stable complexes with both uranyl (UO22+ ) and neptunyl (NpO2+ ) ions and presents a potential new avenue for waste remediation.

Daniel Seidel

Papers

Synthetic expanded porphyrin chemistry.

Synthesechemie expandierter Porphyrine

Cyclo[8]pyrrole: A Simple-to-Make Expanded Porphyrin with No Meso Bridges

Nonlinear optical properties and excited-state dynamics of highly symmetric expanded porphyrins.

Hexaphyrin(1.0.1.0.0.0): An Expanded Porphyrin Ligand for the Actinide Cations Uranyl (UO22+) and Neptunyl (NpO2+)