It is extremely important for chemists to establish the structure of new compounds. A more accurate understanding of the structure leads to the construction of appropriate reaction systems. For example, although the well-known platinum complex, [PtCl2(NH3)2], has two geometrical isomers (cis and trans in Fig. 1), only the cis-isomer (so-called cisplatin) exhibits prominent antitumor activity (R...

We report on a supramolecular self-assembly system that displays coupled light switching, biocatalytic condensation/hydrolysis and gelation. The equilibrium state of this system can be regulated by light, favouring in situ formation, by protease catalysed peptide synthesis, of self-assembling trans- in ambient light; however, irradiation with UV light gives rise to the cis-isomer, which readily...

molecular structure, isomerism, conformational stability and intramolecular hydrogen bonding (ihb) of cis-enol forms of 1-(n-pyridyl)butane-1,3-diones (npbd) (n = 2, 3, or 4) have been investigated by means of density functional theory (dft) calculations. energy differences for all possible npbd cis-enol forms of isomers with respect to the most stable form of the corresponding isomer have been...

The title compound, [Ni(N(3))(2)(C(6)H(6)N(2)O)(2)], was obtained as the first crystalline product from the reaction of Ni(NO(3))(2)·6H(2)O, picolinamide and NaN(3) in aqueous media. After a few days in the mother liquor, crystals of the cis isomer transformed into the trans isomer [Đaković & Popović (2007 ▶). Acta Cryst. C63, m507-m509]. The Ni atom exhibits a distorted octa-hedral environment...

New antibiotics, miyakamides A1, A2, B1, and B2, were isolated from the cultured broth of Aspergillus flavus Link var. columnaris FKI-0739 together with known compounds, parasiticolide A, hydroxyaspergillic acid, and kojic acid. The structure of miyakamide A1 is N-acetyl-L-phenylalanyl-N-methyl-L-phenylalanyl-(alphaZ)-alpha,beta-didehydrotryptamine, and miyakamide A2 is E isomer of A1 at didehy...

An understanding of the photoisomerization mechanism of molecules bound to a metal surface at the molecular scale is required for designing photoswitches at surfaces. It has remained a challenge to correlate the surface structure and isomerization of photoswitches at ambient conditions. Herein, the photoisomerization of a self-assembled monolayer of azobenzene-thiol molecules on a Au surface wa...

A series of alkyl- and aryl-substituted derivatives of cis,cis-1,2,5,6-tetrasilacycloocta-3,7-diene were prepared. Isomerization of these compounds to the corresponding trans,trans-1,2,5,6-tetrasilacycloocta-3,7-dienes by exposure to Ru and Zr hydride complexes was explored. Experimental probes of the isomerization were consistent with a stepwise mechanism involving metal hydride addition/elimi...

A series of benzyl propargyl ethers were synthesized and tested as inhibitors of 5-lipoxygenase, the key enzyme involved in leukotriene biosynthesis. Among these, optimum activity was displayed by 1-(2-heptynyloxymethyl) benzene 12 (IC50 1.2 microM). Addition of carboxyl group at the end of the alkyl side chain attached to the acetylenic group abolished the inhibition. Selective reduction of th...

Photo-induced molecular motion in a liquid crystal polymer film including azobenzene was studied by the heterodyne transient grating method. The film was confined in a liquid crystal cell, where it is a photomobile film under free-standing conditions. By observation of the refractive index change induced by a laser pulse, contraction of the film was observed on the order of several hundreds of ...

Fluorescent protein (FP) variants that can be reversibly converted between fluorescent and nonfluorescent states have proven to be a catalyst for innovation in the field of fluorescence microscopy. However, the structural basis of the process remains poorly understood. High-resolution structures of a FP derived from Clavularia in both the fluorescent and the light-induced nonfluorescent states ...