Synthesis of (−)-Dihydroraputindole D by Enantioselective Benzoylation of a 1,3-Diol Intermediate

The enantioselective synthesis of (−)-dihydroraputindole D is reported. The key step is the desymmetrizing benzoylation of a prochiral 1,3-diol employing Trost′s ProPhenol catalyst system, which has been applied for the first time to a cyclic molecule carrying geminal hydroxymethyl groups. The cyclopenta[f]indoline system was assembled by Au(I)-catalyzed cyclization of an alkynylated indoline precursor. (−)-Dihydroraputindole D was obtained in 17 steps and 8% overall yield starting from dihydroxyacetone. In combination with quantum chemical calculations of the ECD spectra, our synthesis allowed us to determine the absolute configuration (5S,7R) of the natural product (+)-raputindole D from the Rutaceous plant Raputia simulans.     

Bis[N,N′‐bis(2‐nitrocinnamaldehyde)phenylenediimine]copper(I) Perchlorate

The complex [Cu(nitroca₂ph)₂]ClO₄, where nitroca₂ph is N,N′‐bis(2‐nitrocinnamaldehyde)phenylenediimine, crystallizes in the triclinic space group with a = 13.167(1), b = 13.209(1), c = 14.465(1) Å, α = 83.209(9)°, β = 68.438(2)°, γ = 70.803(2)°, V = 2209.4(3) ų, Z = 2, D_calc = 1.527 mg/m³. The coordination polyhedron about the Cu(I) atom is best described as a distorted tetrahedron. 2‐nitroca₂en acts as a bidentate ligand coordinating via two N atoms to the copper. The four Cu–N distances are 2.04 (2), 2.038(2), 2.046(2), and 2.062(2) Å.     

Synthesis,Characterization and X‐ray Crystal Structures of [Cu(ncaen)2]ClO4 and [Cu(nca2en)(PPh3)2]BPh4 Complexes

A novel ligand, N,N′‐Bis‐[3‐(2‐nitrophenyl)‐allylidene]‐ethane‐1,2‐diamine (nca₂en), and their corresponding copper(I) complexes, [Cu(ncaen)₂]ClO₄ ( 1 ), and [Cu(nca₂en)(PPh₃)₂]BPh₄ ( 2 ), have been synthesized and characterized by CHN analyses, ¹H and ¹³C‐NMR, IR, and UV‐Vis spectroscopy. The crystal and molecular structures of [Cu(ncaen)₂]ClO₄ ( 1 ), and [Cu(nca₂en)(PPh₃)₂]BPh₄ ( 2 ), were determined by X‐ray crystallography from single‐crystal data. The coordination polyhedron about the copper(I) atom in the two complexes is best described as a distorted tetrahedron. A quasireversible redox behavior is observed for complex 1 and 2 (E_1/2 = 0.55 and 0.95 V, respectively).     

Quantification of ion-induced molecular fragmentation of isolated 2-deoxy-D-ribose molecules

Recent experiments on low energy ion-induced damage to DNA building blocks indicate that ion induced DNA damage is dominated by deoxyribose disintegration (Phys. Rev. Lett., 2005, 95, 153201). We have studied interactions of keV H+ and He(q+) with isolated deoxyribose molecules by means of high resolution time-of-flight spectrometry. Extensive statistical fragmentation of the molecules is observed. The fragment distribution is found to follow a power law dependence. The exponent can be used to characterize and quantify the molecular damage.     

Interactions of neutral and singly charged keV atomic particles with gas-phase adenine molecules

KeV atomic particles traversing biological matter are subject to charge exchange and screening effects which dynamically change this particle's effective charge. The understanding of the collision cascade along the track thus requires a detailed knowledge of the interaction dynamics of radiobiologically relevant molecules, such as DNA building blocks or water, not only with ionic but also with neutral species. We have studied collisions of keV H(+), He(+), and C(+) ions and H(0), He(0), and C(0) atoms with the DNA base adenine by means of high resolution time-of-flight spectrometry. For H(0) and H(+) we find qualitatively very similar fragmentation patterns, while for carbon, strong differences are observed when comparing C(0) and C(+) impact. For collisions with He(0) and He(+) projectiles, a pronounced delayed fragmentation channel is observed, which has not been reported before.     

Conformation of N,N′-bis (2,6-dimethylmorpholino), N″-dichloroacetyl phosphoric triamide: CHCl2C(O)NHP(O)[2,6(CH3)2(NC4H6O)]2. NMR and ab initio studies

Using phosphorus pentachloride as a substrate, a new carbacyclamidophosphate, N,N″-bis (2,6-dimethylmorpholino), N″-dichloroacetyl phosphoric triamide (1) has been synthesized and characterized by ¹H, ³¹P and ¹³C NMR, IR spectroscopy and elemental analysis. Due to the presence of methyl disubstituted morpholine rings and the dichloroacetamide group, several conformers can be considered for this molecule. The ³¹P{¹H} NMR spectra for the isomeric mixture of synthesized compound showed four signals with the ratio 67.1; 19.0; 12.2; 1.7, which indicates four independent conformers. The ¹H NMR spectra confirmed these results. The conformational space and the molecular geometry of the molecule in the gaseous phase have been studied using the B3LYP method of approximation, with 6-31G and 6-311++G^** basis sets.     

Nonlinear targeted energy transfer: state of the art and new perspectives

Nonlinear Dynamics - Following a brief review of current progress in the field of nonlinear targeted energy transfer (TET), we discuss some general ideas and methods in this field and describe...     

Acoustic manipulation of active spherical carriers: Generation of negative radiation force

This paper examines theoretically a novel mechanism of generating negative (pulling) radiation force for acoustic manipulation of spherical carriers equipped with piezoelectric actuators in its inner surface. In this mechanism, the spherical particle is handled by common plane progressive monochromatic acoustic waves instead of zero-/higher- order Bessel beams or standing waves field. The handling strategy is based on applying a spatially uniform harmonic electrical voltage at the piezoelectric actuator with the same frequency of handling acoustic waves, in order to change the radiation force effect from repulsive (away from source) to attractive (toward source). This study may be considered as a start point for development of contact-free precise handling and entrapment technology of active carriers which are essential in many engineering and medicine applications.