Synthesis, crystal structure, and nonlinear optical behavior of beta-unsubstituted meso-meso E-vinylene-linked porphyrin dimers

[structure: see text] A vinylene-linked porphyrin dimer, with no substituents at the beta-positions, has been synthesized by CuI/CsF promoted Stille coupling. In the crystal structure of this dimer, the C(2)H(2) bridge is twisted by 45 degrees relative to the plane of the porphyrins. The absorption, emission spectra, and electrochemistry reveal substantial porphyrin-porphyrin pi-conjugation. The triplet excited-state absorption spectrum of this dimer makes it suitable for reverse saturable absorption at 710-900 nm.     

Versatile organic (fullerene)-inorganic (CdTe nanoparticle) nanoensembles

Novel organic (positively charged fullerene)-inorganic (negatively charged CdTe nanoparticle) nanoensembles were devised through electrostatic interactions and probed as versatile donor-acceptor hybrids. Photoirradiation of their homogeneous solutions, containing the electrostatically packed components, let to very long-lived (1.3 ms) charge separated states.     

Humic substances of surface waters : Litter and soil throughflow relationships in two forested ecosystems

Humic substances were isolated from the vegetation throughfall, soil drainage waters and adjacent stream waters at two forested sites in the Central Region of Scotland. Fractionation on XAD-8 hydrophobic resin gave three humic substance components and one hydrophilic acid fraction. Norway spruce generally gave 2–3 times more dissolved organic carbon in the litter drainage compared with Sitka spruce, although there was little qualitative difference in organic acidity between the two litterflows. The humic substances in the drainage at ca. 1 m depth (BC horizon) showed considerable differences between sites, reflecting the types of soils and sources of soil water. Phenolic acids released on hydrolysis confirm the differences between sites and may indicate the sources of subsoil water and their relationships with the stream outputs.     

(Fe(III)(OH(2))(2))(3)(A-alpha-PW(9)O(34))(2)](9-) on cationic silica nanoparticles,a new type of material and efficient heterogeneous catalyst for aerobic oxidations

Polyoxometalates (POMs) electrostatically bind to silica nanoparticles coated with cationic aluminum oxide "(Si/AlO2)n+" to form a new type of material (the anionic POMs replace Cl- counterions associated with the cationic surface sites). Association of a new approximately D3h POM of formula [(FeIII(OH2)2)3(A-alpha-PW9O34)2]9- (1) with the cationic nanoparticles (to form "K81/(Si/AlO2)") was studied in detail. Elemental analysis, particle sizes from both laser light scattering and TEM before and after association of 1, the size of 1 from X-ray crystallography, and other methods provide mutually consistent data that indicate about 58 K8[(FeIII(OH2)2)3(A-alpha-PW9O34)2]- monoanions associate with the average nanoparticle (diameter of the K81/(Si/AlO2) product = approximately 17 nm). While heterogeneity of the cationic sites and roughness of the (Si/AlO2)n+ surfaces make the associated POMs structurally nonuniform, the equivalent of approximately 1 monolayer of 1 is present in K81/(Si/AlO2). Remarkably, while 1, the precursor (Si/AlO2)n+, and the components of 1, each alone, are inactive as catalysts for O2/air-based oxidation of sulfides or aldehydes in solution, K81/(Si/AlO2) is an active catalyst for both reactions (facile reaction with air at low temperature).     

Oxygen isotope corrections for online delta(34)S analysis

Elemental analyzers have been successfully coupled to stable-isotope-ratio mass spectrometers for online measurements of the delta(34)S isotopic composition of plants, animals and soils. We found that the online technology for automated delta(34)S isotopic determinations did not yield reproducible oxygen isotopic compositions in the SO(2) produced, and as a result calculated delta(34)S values were often 1-3 per thousand too high versus their correct values, particularly for plant and animal samples with high C/S ratio. Here we provide empirical and analytical methods for correcting the S isotope values for oxygen isotope variations, and further detail a new SO(2)-SiO(2) buffering method that minimizes detrimental oxygen isotope variations in SO(2).     

Rapid synthesis of acyl transfer auxiliaries for cysteine-free native glycopeptide ligation

[reaction: see text] Rapid, facile routes to the TFA-cleavable 4,5,6-trimethoxy-2-mercaptobenzyl and 1-(2,4-dimethoxyphenyl)-2-mercaptoethyl classes of auxiliaries for cysteine-free native chemical ligation are described. Rapid synthesis, coupled with mild cleavage conditions will undoubtedly broaden the utility of such auxiliaries, particularly where chemically fragile peptide modifications such as glycosylation are present.     

MUTATIONS IN SACCHAROMYCES CEREVISIAE AFFECTING SENSITIVITY TO PHOTODYNAMIC INACTIVATION

Abstract— Mutants of Saccharomyces cerevisiae with varying photodynamic sensitivities were isolated in an attempt to help identify the cytoplasmic targets of photodynamic action in yeast.     

First Synthesis of 3-Mercapto-2(1H)-pyridinone, a Simple Disubstituted Pyridine Useful for Synthesis of the 4-Azaphenoxathiine Ring System and Its Novel Diazaphenoxathiine Analogs: 1,6-Diazaphenoxathiine and 2,6-Diazaphenoxathiine(1)

3-Mercapto-2(1H)-pyridinone (1) can be synthesized in three simple high-yielding steps from readily available 2-tert-butylthiazolo[4,5-b]pyridine (2). Its disodium salt condenses with o-chloronitrobenzene, 2-chloro-3-nitropyridine, and 3-chloro-4-nitropyridine 1-oxide to give respectively 4-azaphenoxathiine (10), 1,6-diazaphenoxathiine (12), and 2,6-diazaphenoxathiine 2-oxide (14) which reduces to 2,6-diazaphenoxathiine (15). The structures of these previously unreported azaphenoxathiine systems were confirmed by assignment of their respective (13)C NMR spectra.     

Cupric decamolybdodivanadophosphate. A coordination polymer heterogeneous catalyst for rapid, high conversion, high selectivity sulfoxidation using the ambient environment

A new type of coordination network polymer involving the redox-active polyanion, PV(2)Mo(10)O(40)(5)(-), and bridging -Cu(II)(OH(2))(4)- units, [[(Cu(II)(OH(2))(4))(3)(OH)]PV(2)Mo(10)O(40)](n)() (1), has been characterized by X-ray crystallography and several other methods. It is the first efficient heterogeneous (insoluble) catalyst for selective and rapid sulfoxidation using only the ambient environment (air at room temperature). Catalytic activity is enhanced by soluble nitrate in nontoxic perfluoropolyether (PFPE) media.