Controlled Synthesis of Statistical Polycarbonates Based on Epoxides and CO2

The controlled synthesis of terpolymer structures is often limited by the intrinsic reactivities of the monomers. For the synthesis of a statistical terpolymer from cyclohexene oxide (CHO) and propylene oxide (PO) with CO₂, an instrumental solution is demanded. Implementing a setup where one monomer can be added to the reaction mixture over the whole course of the reaction, the random distribution of the epoxides over the whole chain is realized. The successful terpolymerization can be determined with diffusion-ordered nuclear magnetic resonance spectroscopy and gel permeation chromatography measurements while the statistical microstructure of the generated polymers is indicated in NMR spectroscopy and differential scanning calorimetry measurements. Furthermore, the concept is transferred to the terpolymerization of limonene oxide with PO and CO₂ underlining the versatility of the setup.     

Analysis of dipyridine dipyrrole based molecules for solar cell application using computational approach

Journal of Computational Electronics - In this work, six dipyridine dipyrrole (DPDP) derivatives are reported as π-conjugated, electron donor molecules used in BHJ solar cells. Density...     

Mapping the Melatonin Receptor. 8. Selective MT2 Agonists Derived from 5,6-Dihydroindolo[2,1-a]isoquinolines and Related Systems

A series of substituted indolo[2,1-a]isoquinolines and indolo[1,2-a]benzoxazines have been prepared, as melatonin analogues, to investigate the nature of the binding site of the melatonin receptor. Agonist and antagonist potency of all the analogues was measured using the [35S]GTPγS binding assay protocol. The binding affinity of the analogues were measured by competition binding studies against the human MT1 (hMT1) and MT2 (hMT2) receptors stably transfected in Chinese Hamster Ovarian (CHO) cells, using 2-[¹²⁵I]-iodomelatonin, as a ligand. N-Acetyl 2-(10-methoxy-5,6-dihydroindolo[2,1-a]isoquinolin-12-yl)propyl-1-amine (12 a) binds strongly to both the hMT1 and hMT2 receptors, and shows a preference for the hMT2, as does its propanamido counterpart 12 b . The introduction of two methyl groups into their side chain, analogues 15 a and 1 5 b , leads to antagonism, in the case of the former, and drastically diminishes its hMT1 binding; an analogous profile is seen for 15 b , which, however, is a partial agonist. Introduction of chlorine or methoxy groups into ring 4 gives compounds, that are weakly binding, with a preference for MT2. Substitution of oxygen for carbon at position 5 gives the indolo[1,2-c]benzoxazines 33 , 36 a and b , that bind strongly to the human receptors, 33 , 36 b being potent agonists at the melatonin receptors, but do not discriminate between hMT1 and hMT2.     

The Alkali Metal Reduction of Trimethoxybenzenes in hydrocarbon solvents

A series of trimethoxybenzenes was subjected to reduction in hydrocarbon solvents. 1,2,3-Trimethoxybenzene ( 1 ) and 1,2,4-trimethoxybenzene ( 2 ) underwent selective demethoxylation in high yields, whereas the 1,3,5-substituted isomer 3 proved resistant to the reduction conditions. The reactions mechanism involves the fission of a methoxyl radical from an initial radical anion. The accompanying side-reactions, i.e. demethylation and deoxygenation, may be suppressed by the addition of n-butanol as a proton source.     

ACHEMA 2022: Innovationen und Trends in der Trocknungstechnik

This contribution aims to summarize the highlights of the innovations displayed at ACHEMA 2022 and to report on the observed trends. Aside from new equipment in individual areas of drying, the advances of the exhibiting companies in the areas of digitalization and sustainability were examined in greater detail.     

PEGylation Effects on the Interaction of Sphingomyelin Nanoemulsions with Serum Albumin: A Thermodynamic Investigation

The recent focus in the development of novel nanosystems for biomedical applications lays firmly on their interactions with biomolecules. Thermodynamic parameters driving the interaction between nanoparticles and proteins provide insights into complex processes at bio/nanointerface. The present work aims to investigate the binding mechanisms and the dominant contributions that determine the adsorption processes during the interactions of a model protein, that is, bovine serum albumin, with a new type of drug delivery systems, Vitamin E/sphingomyelin nanoemulsions, plain and coated with polyethylene glycol, and d -ɑ-tocopheryl polyethylene glycol succinate. The binding parameters (binding constant, binding stoichiometry, enthalpy, Gibbs energy, and entropy changes of binding) are evaluated by the isothermal titration calorimetry with a MicroCaliTC200 equipment. The effect of nanoemulsions on the protein stability is examined by measuring the thermodynamic parameters for the protein's unfolding (heat capacity; enthalpy, entropy, and free energy changes) with a NanoDSC (TA Instrument) apparatus. The thermodynamic profile shows for all compositions an entropy-driven interaction dominated by hydrophobic forces due to the rearrangements/displacement of the surrounding water molecules, while maintaining the native conformation of the protein. All the information acquired by thermodynamic approach may significantly enhance the knowledge with special focus on PEGylated nanoemulsions used for biomedical applications.