Confirmation of Complex Formation Between Ethylene and Mercury Halides by Matrix-Isolation Infrared Spectroscopy

Since DeKock¹ first prepared the Ni(CO)_n (n = 1,2,3 and 4) series in argon matrices, a number of unstable and transient coordination compounds have been synthesized by reacting metal vapor directly with the ligand in inert gas matrices at low temperatures. These include metals such as Pt, Pd and Ni, and ligands such as CO, N₂′ NO, O₂ and PF₃. Van Leirsburg and DeKock² prepared the MX₂-L type complexes by reacting metal halide vapor such as NiF₂ and NiCl₂ directly with ligands such as CO, NO and N₂ in argon matrices. Thus far, no reports are available on the synthesis of metal halid-ethylene complexes in inert gas matrices. In this letter, we wish to report the confirmation of such complex formation by matrix-isolation infrared spectroscopy.     

Study on the spin crossover transition and glass transition for Fe(II) complex film, [Fe(II)(H-triazole) 3 ]@Nafion, by means of M?ssbauer spectroscopy

[Fe(II)(H-trz)₃]@Nafion (trz = triazole) is a transparent spin crossover complex film, where the spin crossover transition between the low-spin (S = 0) and the high-spin (S = 2) states takes place between 225?K and 300?K. In this film, two doublets corresponding to the low-spin and high-spin states were observed in the ⁵⁷Fe M?ssbauer spectra, reflecting the spin crossover transition. From the analysis of ⁵⁷Fe M?ssbauer spectra, the Debye temperatures of the low-spin and high-spin sites were estimated at 185?K and 176?K, respectively, in the temperature range between 10?K and 150?K. In this film, the total intensity of the M?ssbauer spectra corresponding to the low-spin and high-spin sites drastically decreases above 200?K, reflecting the glass transition of Nafion, where the lattice vibration of [Fe(H-trz)₃] $_{\rm n}^{\,\,\rm 2n+}$ is softened just as in solution due to micro-Brown motion of the segment of Nafion polymer membrane.     

Alternative medicine safety: agaricus blazei and propolis

All medicines pose a potential health risk, be they Eastern or Western medicines. Newly developed Western drugs must undergo rigorous testing to ensure their efficacy and safety, while with Eastern drugs, safety has generally been established because of their long histories of safe usage as traditional medicines. The regulation of Western medicines is much stronger than that of Eastern medicines, partly as pure chemicals are used and their effects and side effects are more likely to be acute. Eastern medicines consist of multiple components, generally extracted from a single or several plants or other natural sources, and their effects are not so acute, with delayed onset of side effects. However, the chronic usage of many Eastern medicines may result in the gradual accumulation of toxic compounds in the body. For example, Agaricus blazei extracts have been used as alternative medicines for cancer, but contain the known carcinogen agaritine (this carcinogen is also present in Agaricus bisporus). To ensure the safety of this alternative medicine, agaritine should be removed or its content reduced if the extract is to be taken chronically. Clearly, the safety of not only pure medicines, but also alternative medicines and daily foods, should be carefully controlled.     

Photoisomerization of perfluoroaryltetrahedranes to perfluoroarylcyclobutadienes

Two perfluoroaryl-substituted cyclobutadiene derivatives, 6 and 7, were prepared as air- and moisture-sensitive red solids by the photochemical isomerization of the corresponding tetrahedranes (4 and 5, respectively). Remarkably, the 9,10-dicyanoanthracene-sensitized photochemical reaction of 4 also proceeded, giving 6, and the mechanism of this reaction is also discussed. The first aryl-substituted cyclobutadienes were characterized by spectroscopic data as well as by X-ray crystallography for 6, showing a distorted rectangular structure with extremely long C-C single bonds.     

Absolute Configuration of 4-α-D-Glucopyranosyl-myo-inositol,Enzymatic Transglycosylation Product

Abstract

The absolute configuration of 4-α-D-glucopyranosyl-myo-inositol, one of the enzymatic transglycosylation products from cyclodextrin to myo-inositol, was confirmed by chemical synthesis. The glycosylation was shown to proceed in a highly diastereoselective manner by HPLC analysis of the chemically synthesized racemic glycoside.     

The detection of glycosphingolipids in brain tissue sections by imaging mass spectrometry using gold nanoparticles

Glycosphingolipids (GSLs) are amphiphilic molecules consisting of a hydrophilic carbohydrate chain and a hydrophobic ceramide moiety. They appear to be involved primarily in biological processes such as cell proliferation, differentiation, and signaling. To investigate the mechanism of brain function in more detail, a more highly sensitive method that would reveal the GSL distribution in the brain is required. In this report, we describe a simple and efficient method for mapping the distribution and localization of GSLs present in mouse brain sections using nanoparticle-assisted laser desorption/ionization imaging mass spectrometry (IMS). We have developed and tested gold nanoparticles (AuNPs) as a new matrix to maximize the detection of GSLs. A matrix of AuNPs modified with alkylamine was used to detect various GSLs, such as minor molecular species of sulfatides and gangliosides, in mouse brain sections; these GSLs were hardly detected using 2,5-dihydroxybenzoic acid (DHB), which is the conventional matrix for GSLs. We achieved approximately 20 times more sensitive detection of GSLs using AuNPs compared to a DHB matrix. We believe that our new approach using AuNPs in IMS could lead to a new strategy for analyzing basic biological mechanisms and several diseases through the distribution of minor GSLs.     

Diagonal Transformations of Graphs and Dehn Twists of Surfaces

In this paper we shall show that any two bipartite quadrangulations of a closed surface can be transformed into each other by diagonal slides and diagonal rotations, up to isotopy, if they have the same and sufficiently large number of vertices. Also, we show the same fact for triangulations of a closed surface.     

The links of 3‐dimensional singularities defined by Brieskorn polynomials

In this paper, we completely determine the diffeomorphism types of the 5‐dimensional links of 3‐dimensional log‐canonical singularities defined by Brieskorn polynomials. Moreover, we show that if k is an integer with 1 ≤ k < 611, then there is no link K defined by a Brieskorn polynomial in ?⁴ such that the order of H₂(K) is 6k. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spirophosphoranide (10-P-4) with Hexafluoro-2-Phenyl-2 - Propanol: X-Ray Structure,Stereomutation and Substitution

Abstract

J. C. Martin and I. Granoth reported observation of a stable spirophosphoranide 2-Li[l]. Here we confirmed the structure of 2-Li by X-ray analysis and the stereomutational behavior was examined. The X-ray analysis of 2-Li shows slightly distorted pseudo-trigonal bipyramidal structure with equatorial lone pair electrons.