Phase Modification of Ammonium Nitrate by Potassium Salts

Modification of the room temperature phase (IV-III) of ammonium nitrate (AN) has been attempted using a variety of potassium salts namely, KF, KCl, KI, KNO₃, K₂CO₃, K₂SO₄, KSCN and K₂Cr₂O₇. No phase transition was observed when AN containing 1–2% by mass of these potassium salts is heated from room temperature (25°C) onwards in DTA and DSC scans, but the linear expansion due to phase transition was still observable in TMA measurements. Complete arrest of the linear expansion occurs only when a higher concentration of the additive is used. Similarly, in thermal cycling experiments, complete phase modification in the temperature range -80 to 100°C occurs only with a higher percentage of the potassium salt. The extent of modification, however, is found to be dependent both on the concentration, and the type of the anion. Potassium dichromate when used as an additive modifies the phase as well as the decomposition pattern of AN. This revised version was published online in July 2006 with corrections to the Cover Date.     

Three components synthesis of homoallylic amines catalyzed by bismuth(III) nitrate pentahydrate

Bismuth (III) nitrate pentahydrate catalyzes efficiently the three-component condensation of aldehydes, amines, and allyltributylstannane at rt to afford the corresponding homoallylic amines in excellent yield.     

Determination of Allosteric Effects and Interstrand Bidentate Interactions in DNA‐Peptide Molecular Recognition

To study DNA allostery, quantitative DNase I footprinting studies were carried out on a newly designed peptide His‐Hyp‐Lys‐Lys‐(Py)₄‐Lys‐Lys‐NH₂ (HypKK‐10) containing the XHypKK (Hyp = hydroxyproline) and polyamide motifs. The interconnection of DNA footprints of peptides HypKK‐10 and the parent peptide PyPro‐12 supports the proposal that interaction network cooperativity is preferred in DNA‐peptide interactions between multiple recognition sites. A simple method of determining interstrand bidentate interactions between the peptide moieties and DNA bases is introduced. It is envisaged that interstrand bidentate interactions also participate in the relay of conformational changes to recognition sites on the complementary strands. Circular dichroism studies of the titration of peptide HypKK‐10 with an oligonucleotide duplex indicate that this peptide binds in a dimeric fashion to DNA in the minor groove. This work may prompt the design of new DNA binding ligands for the study of DNA‐peptide allosteric interactions and DNA interaction network.     

CAN Catalyzed One‐Pot Synthesis of α‐Amino Phosphonates from Carbonyl Compounds

Abstract

α‐Amino phosphonates are synthesized by three component condensation of aldehydes, amines, and diethyl phosphite using ceric ammonium nitrate at room temperature to afford the corresponding α‐amino phosphonates in high yields.     

Thermal Analysis for Control of the Properties of Mineral Fertilizers

The development of equipment for thermal analysis has opened up new areas for applications in science, industrial practice and environment studies. On the basis of the literature and information from equipment producers, the directions for the use of thermal analysis in research and practice are classified. Special attention is paid to the possibilities of controlling environmental pollution, and the stability and other properties of intermediate and final industrial products. It is stressed that DSC and DTA systems can be successfully applied to determine enthalpy changes in raw materials and products as control tests for their application. The advantages of coupled thermal systems for complex studies and the control of raw materials, products and wastes are described. This revised version was published online in August 2006 with corrections to the Cover Date.     

由氯化钠制硝酸钠的转化法研究

我国硝石矿很少,硝酸钠主要靠合成法生产,即用纯碱(或烧碱)溶液吸收硝酸“尾气”而得:     

Stimulated Raman conversion of radiation from a YAG:Nd laser with wavelengths of 1.319, 1.338, and 1.357 µm in a barium nitrate crystal

We have studied stimulated Raman (SRS) conversion to the first Stokes component of multimode (M₂ = 8) radiation from a YAG:Nd laser with lasing wavelengths of 1.319 μm, 1.338 μm, and 1.357 μm in a barium nitrate crystal. We have obtained pulses of converted radiation with energies up to 120 mJ. We have achieved conversion efficiencies greater than 40% for each of the three Raman laser wavelengths of 1.530 μm, 1.556 μm, and 1.582 μm with divergence of the beams of converted radiation close to the diffraction-limited value (M₂ < 1.5). __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 330–334, May–June, 2006.     

硝酸铵的一种敏化技术

介绍一种在表面活性剂作用下，采用真空改性结晶技术，制备膨松、轻质和多微孔隙硝酸铵的方法。用该硝酸铵混制的铵木油炸药，具有良好的起爆和传爆性能、作功能力大、爆速高，是一种可以取代铵梯炸药，适宜于工业生产和广泛用于工程爆破的炸药。     

Yttrium(III) Nitrate: A Powerful Catalyst for Green and Rapid Synthesis of Some Supramolecules

A convenient and rapid procedure for the synthesis of calix[4]resorcinarenes as useful supramolecules has been developed via a reaction of aryl aldehydes with resorcinol in the presence of yttrium(III) nitrate under solvent‐free conditions. This eco‐friendly method has many appealing attributes such as excellent yields, short reactions times, and simple work‐up procedures.     

Complementary Lock‐and‐Key Ligand Binding of a Triplet Transmitter to a Nanocrystal Photosensitizer

Owing to the difficulty in comprehensively characterizing nanocrystal (NC) surfaces, clear guidance for ligand design is lacking. In this work, a series of bidentate bis(pyridine) anthracene isomers (2,3‐PyAn, 3,3‐PyAn, 2,2‐PyAn) that differ in their binding geometries were designed to find the best complementary fit to the NC surface. The efficiency of triplet energy transfer (TET) from the CdSe NC donor to a diphenylanthracene (DPA) acceptor mediated by these isomers was used as a proxy for the efficacy of orbital overlap and therefore ligand binding. 2,3‐PyAn, with an intramolecular N–N distance of 8.2 Å, provided the best match to the surface of CdSe NCs. When serving as a transmitter for photon upconversion, 2,3‐PyAn yielded the highest upconversion quantum yield (QY) of 12.1±1.3 %, followed by 3,3‐PyAn and 2,2‐PyAn. The TET quantum efficiencies determined by ultrafast transient absorption measurements showed the same trend.