Edward Krzyżak

Phase Diagram for the RbBr–CuBr System

The phase diagram for the RbBr–CuBr system has been determined. In the system two intermediate compounds are formed: RbCu2Br3, melting congruently at 537 K and Rb3CuBr4, melting incongruently at 544 K. The coordinates of the two eutectic points are: 501 K, 54 mole% CuBr and 522 K, 74 mole% CuBr.

Synthesis and thermal behaviour of new benzo-1,2-thiazine long-chain aryl-piperazine derivatives

A series of potential biologically active 2-[3-(4-phenyl-1-piperazinyl)propyl]-3-(4-substituted-benzoyl)-4-hydroxy-2H-1,2-benzothiazine 1,1-dioxides was synthesized in a straightforward manner by condensation of respective 3-substituted-4-hydroxy-1,2-benzothiazine 1,1-dioxides with 1-(1-chloropropyl)-4-phenylpiperazine. The structures of all of the newly formed compounds were identified by elemental analysis, FTIR and 1H NMR. The synthesized compounds were subjected to preliminary evaluation using differential scanning calorimetry (DSC) to determine the existence of multiple crystal forms. The DSC scans for all compounds show more than one endothermic effect, which might suggest dynamic proton transfer between two or three possible tautomeric forms: O-keto/O-enol, O-enol/O-keto and O-keto/O-keto/CH2 in crystals 2-[3-(4-phenyl-1-piperazinyl)propyl]-3-(4-substituted-benzoyl)-4-hydroxy-2H-1,2-benzothiazine 1,1-dioxides.

Synthesis and thermal study of new N-substituted 1H-pyrrolo[3,4-c]pyridine-1,3(2H)diones of Mannich base type

The new derivatives of 3,4-pyridinedicarboximide were synthesised. Experimental measurements were carried out using 1H NMR spectra, IR spectra, elemental analyses and differential scanning calorimetry. The purpose of this study was to study the thermal stability of these four new compounds and to establish a solid-state polymorphism. Measurements were carried out for samples obtained from ethanol and n-hexane and after a long-time storage.

Synthesis and fluorescence properties of new ester derivatives of isothiazolo [4,5-b] pyridine.

A two new compounds with potential biologically active were synthesized: ethyl 4-(2H-4,6-dimethyl-3-oxo-2,3-dihydroisothiazolo [5,4-b] pyridin-2-yl) butanoate and ethyl 4-(2H-4,6-dimethyl-2,3-dihydroisothiazolo [5,4-b] pyridin-3-yloxy) butanoate. The structures of all of the newly formed compounds were identified by elemental analysis, FTIR and 1H NMR. Their optical properties were studied in ethanol and n-hexane by UV–Vis absorption and fluorescence spectroscopy. The ground-state and excited-state properties were investigated using the density functional theory (DFT) and the time-dependent density functional theory (TDDFT) methods. The results showed differences between emission spectra in ethanol and n-hexane solution (solvatochromism) for both new compounds.

The Coordination Abilities of Three Novel Analogues of Saliva Peptides: The Influence of Structural Modification on the Copper Binding

Three novel analogues of salivary peptides as sialorphin (QHNPR) and opiorphin (QRFSR) were synthesized by the solid-phase method. The sequences of these ligands were following: AHNPR, QANPR and QRFPR. The aim of our work was investigation in what way some structural modifications may impact on coordination abilities of studied peptides. In this work we presented the interaction of pentapeptides with copper(II) ions in wide range of pH. To determine the coordination model of ligands there were carried out several studies by spectroscopy (UV–Vis, CD) methods and potentiometric measurements.