Synthesis Derivatives of 2‐Amino‐4‐quinolones from 1,2,3,4‐Tetrahydroquinoline‐8‐carboxylic acids

A simple and efficient method is developed. Novel 2‐amino‐4‐quinolone derivatives are synthesized. The products that have several functional groups for possible future modifications are described.     

Alkali-metal-supported bismuth polyhedra-principles and theoretical studies

We have quantum chemically investigated the structure, stability, and bonding mechanism in highly aggregated alkali-metal salts of bismuthanediide anions [RBi](2-) using relativistic density functional theory (DFT, at ZORA-BP86/TZ2P) in combination with a quantitative energy decomposition analysis (EDA). Our model systems are alkali-metal-supported bismuth polyhedra [(RBi)(n)M(2n-4)](4-) with unique interpenetrating shells of a bismuth polyhedron and an alkali-metal superpolyhedron. Furthermore, we have analyzed the trianionic inclusion complexes [M'@{(RBi)(n)M(2n-4)}](3-) involving an additional endohedral alkali-metal ion M'. The main objective is to assist the further development of synthetic approaches toward this class of compounds. Our analyses led to electron-counting rules relating, for example, the number of bonding orbitals (N(bond)) of the cage molecules [(RBi)(n)M(2n+Q)](Q) to the number of bismuth atoms (n(Bi)), alkali-metal atoms (n(M)), and net charge Q as N(bond) = n(Bi) + n(M) - Q (R = one-electron donor ligand; M = alkali metal; n = 4-12; Q = -4, -6, -8). Finally, on the basis of our findings, we predict the next members in the 5-fold symmetrical row of alkali-metallobismaspheres with a macroicosahedral arrangement.     

Oligomer orientation in vapor-molecular-layer-deposited alkyl-aromatic polyamide films

The surface-limited molecular-layer deposition of alkyl-aromatic polyamide films using sequential doses of 1,4-butane diamine (BDA) and terephthaloyl dichloride (TDC) is characterized using in situ quartz crystal microbalance and ex situ spectroscopy analysis. For the first time, near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is used to offer insight into molecular orientation in films deposited via molecular-layer deposition (MLD). The results show that the oligomer units are lying nearly parallel to the surface, which differs from the linear vertical growth mode often used to illustrate film growth.     

Red‐Emitting Rhodamines with Hydroxylated,Sulfonated, and Phosphorylated Dye Residues and Their Use in Fluorescence Nanoscopy

Fluorescent dyes emitting red light are frequently used in conventional and super‐resolution microscopy of biological samples, although the variety of the useful dyes is limited. We describe the synthesis of rhodamine‐based fluorescent dyes with absorption and emission maxima in the range of 621–637 and 644–660 nm, respectively and demonstrate their high performance in confocal and stimulated emission depletion (STED) microscopy. New dyes were prepared by means of reliable chemical transformations applied to a rhodamine scaffold with three variable positions. They feature polarity, water solubility, variable net charges, improved stabilities of N‐hydroxysuccinimidyl (NHS) esters, as well as large fluorescence quantum yields in dye solutions and antibody conjugates. The photophysical and imaging properties of dyes containing three different polar groups, namely primary phosphate, sulfonic acid (in two different positions), and hydroxyl were compared. A dye with two primary phosphate groups was explored as a valuable alternative to dyes with “classical” sulfonic acid groups. Due to the increased net charge of the phosphorylated dye (q=?4 at pH 8), it demonstrated a far better electrophoretic mobility compared with analogues with two sulfonic acid groups (q=?2). As an example, one fluorescent dye was designed to be especially convenient for practical use. It is characterized by sufficiently high chemical stability of the NHS ester, its simple isolation, handling, and solubility in aqueous buffers, as well as in organic solvents. All these features, accompanied by a zero net charge in conjugates, were accomplished by the introduction of hydrophilic groups of two types: two hydroxyl groups and one sulfonic acid residue.     

Design and Application of In Vivo FRET Biosensors to Identify Protein Prenylation and Nanoclustering Inhibitors

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Highlights? Cellular FRET biosensors for Ras, Rho, and Rab membrane anchorage were developed ? We provide evidence for Rab protein nanoclustering on cellular membranes ? Two FRET biosensors were demonstrated to be suitable for high-throughput screening ? Macrotetrolides were identified as nanoclustering and MAPK signaling disruptors     

Heterogeneous addition of H2 to double and triple bonds over supported Pd catalysts: a parahydrogen-induced polarization technique study

In this work, the contribution of the pairwise H(2) addition to the overall reaction mechanism was studied under the systematic variation of both the Pd particle size and the properties of the catalyst support using the hydrogenation of propene and propyne over supported Pd catalysts as representative examples. For Pd supported on alumina, silica and zirconia, only propene formed upon hydrogenation of propyne with para-H(2) exhibits hyperpolarization. In contrast, propane formed in hydrogenation of propyne or propene is not hyperpolarized. This demonstrates the existence of different routes of H(2) addition to double and triple bonds on supported Pd catalysts. The unique ability of Pd/TiO(2) catalysts to add H(2) in a pairwise manner not only to the triple but also to the double bond is demonstrated. This finding indicates that the Pd-support interaction is of primary importance in determining not only the magnitude of the hyperpolarization of the NMR lines of the reaction products but even the involvement of the pairwise H(2) addition and hence the mechanism of heterogeneous hydrogenation. The comparative analysis of the selectivities toward pairwise H(2) addition suggested the existence of different surface active sites responsible for all three reaction routes: the direct total hydrogenation of propyne into propane, its selective hydrogenation into propene, and hydrogenation of propene into propane. A reaction scheme which accounts for the formation of the observed hyperpolarized and non-polarized reaction products in propyne and propene hydrogenation with para-H(2) over supported Pd catalysts is suggested. For the first time, application of the PHIP technique allowed us to demonstrate that hydrogenation of propene does not take place in the presence of propyne on supported Pd catalysts.     

Efficient scrambling-free synthesis of heteroleptic terbium triple-decker (porphyrinato)(crown-phthalocyaninates)

New heteroleptic triple-decker terbium complexes of general structure [Br(4)TPP]Tb[(15C5)(4)Pc]Tb[Br(4)TPP] (Tb-TD) and [Br(4)TPP]Tb[(15C5)(4)Pc]Tb[(15C5)(4)Pc] (Tb-TD*) (Br(4)TPP = tetrakis-meso-(4-bromophenyl)-porphyrin, (15C5)(4)Pc = tetra-(15-crown-5)-phthalocyanine) are synthesized with 48% and 57% yields, respectively. The triple-decker complexes were prepared by interaction of generated in situ terbium monoporphyrinate [Br(4)TPP]Tb(acac) and corresponding double-decker precursors. The heteroleptic double-decker precursor [Br(4)TPP]Tb[(15C5)(4)Pc] was prepared for the first time in a two step one-pot synthesis. No ligand scrambling was observed in the synthesis of Tb-TD, while 4% scrambling was determined in the case of Tb-TD*. High yields of target triple-decker complexes were achieved despite the presence of electron-donating crown-ether fragments with low thermal stability at the phthalocyanine deck. Analysis of lanthanide-induced paramagnetic shifts of protons of Tb-TD together with data of previously reported La, Pr, Nd and Eu analogues allowed precise separation of contributions of contact and dipolar lanthanide terms as well as verification of isostructurality of complexes within the series.