Weak Pnictogen Bond with Bismuth: Experimental Evidence Based on Bi−P Through-Space Coupling

To study pnictogen bonding involving bismuth, flexible accordion-like molecular complexes of the composition [P(C₆H₄-o-CH₂SCH₃)₃BiX₃], (X=Cl, Br, I) have been synthesised and characterised. The strength of the weak and mainly electrostatic interaction between the Bi and P centres strongly depends on the character of the halogen substituent on bismuth, which is confirmed by single-crystal X-ray diffraction analyses, DFT and ab initio computations. Significantly, ²⁰⁹Bi–³¹P through-space coupling (J=2560 Hz) is observed in solid-state ³¹P NMR spectra, which is so far unprecedented in the literature, delivering direct information on the magnitude of this pnictogen interaction.     

Non-Racemic Mixtures of 1,3,2-Oxazaphosphacyclanes - Enantiomeric Composition Determination by NMR

Abstract

The enantiomeric ratio in non-racemic mixtures of 2-anilino-2-oxo-1,3,2-oxazaphospho-rinane (I) and 3-(α-rnethylbenzyl)-(I)¹ enantiomers was determined by measurement of the integral intensity ratio of two ³¹P-NMR signals, assigned to enantiomers and differentiated due to the effect of statistically controlled associate-diastereoisomerim (scada), ² when association occurs under conditions of fast exchange.     

Synthesis of 5,10,15,20-tetra[6' -nitro-1,3,3-trimethylspiro- (indolino-2,2' -2H-chromen-5-yl)]porphyrin and its metal complexes

A new 5,10,15,20-tetrasubstituted porphyrin containing four 6’-nitro-1,3,3-trimethylspiro(indolino-2,2’-2H-chromene) substituents and its complexes with Zn²⁺ and Cu²⁺ ions were prepared and characterized by physicochemical methods of analysis.     

A layer potential analysis for transmission problems for Brinkman‐type systems in Lipschitz domains in

The aim of this paper is to establish a well‐posedness result for a boundary value problem of transmission‐type for the standard and generalized Brinkman systems in two Lipschitz domains in , the former being bounded, and the latter, its complement in . As a first step, we establish a well‐posedness result for a transmission problem for the standard Brinkman systems on complementary Lipschitz domains in by making use of the Potential theory developed for such a system. As a second step, we prove our desired result (in L²‐based Sobolev spaces) by using a method based on Fredholm operator theory and the well‐posedness result from the previous step.     

Separation technique based on electrophoresis,chromatography and magnetism phenomena: the migration time and peak broadening

1. Download : Download high-res image (108KB)
2. Download : Download full-size image

     

Different spectrophotometric methods for antioxidant activity assay of four Romanian herbs

The present study investigates the antioxidant activities of some Romanian plants, using different spectrophotometric methods (FRAP I, FRAP II, and CUPRAC). The plants investigated are hawthorn (Crataegus oxyacantha), bilberry (Vaccinium myrtillus L.), rosehip (Rosa canina), and chokeberries (Aronia melanocarpa). Hawthorn is used to treat a wide variety of inflammatory conditions, but the primary use is generally restricted for treating hypertension, ischemic heart disease, congestive heart failure, and arrhythmia. Investigations have proved the safe and reliable use of plant and plant extracts for treatment of cardiovascular disorders.