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1

Kompleksy platyny typu Markó zawierające n-heterocykliczne ligandy karbenowe o właściwościach supersterycznych

Bolt Małgorzata, Żak Patrycja

Wiadomości Chemiczne

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2021

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[Z] 75, 1-2

31--53

EN

Progress in technology implying increasing demand for advanced materials dedicated for specific application has become a driving force stimulating research in different branches of science. It has been estimated that over 90% highly processed compounds have been obtained by the methods whose pivotal processes take place in the presence of catalysts based on transition metal complexes. Although these processes permit obtaining desired products, they are often charged with numerous drawbacks that prevent their implementation in industry. That is why the search for new catalytic systems ensuring high efficiency of final products and a possibility of reaction control is still an important direction of studies. Markó complexes are a group of platinum(0) coordination compounds of type [(NHC)Pt(dvtms)]. Although much attention has been recently attracted to these class of compounds, their number reported in hitherto literature is still limited. Owing to the possibility of wide modification of NHC carbene ligand attached to metal, the structures, and thus also properties, of the final complexes can be relatively easily matched to the requirements of individual catalytic reactions. It is particularly interesting in view of permanent development of new technologies and still increasing demand for new synthetic methods of more sophisticated materials dedicated to specific applications. In this paper, the synthesis and characterization of Markó type platinum(0) complexes containing bulky N-heterocyclic carbene ligands is described and their applications in the synthesis of new and unknown organic and organosilicon compounds are discussed. The main advantages of these complexes are highlighted providing an overview of this fascinating area of research.

2

Dimerization of Copper Octacarboxyphthalocyanine in Aqueous Solutions

Suchan A., Nackiewicz J., Hurek J., Wacławek W.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 12

1937-1947

EN

Spectral absorption UV-Vis investigations on association of copper(II) octacarboxyphthalocyanine in aqueous solutions are reported. In 5.0x10-7-5.0x10-5 mol/dm3 concentration range monomers and dimers are mainly present. The calculated dimerization constant 106dm3/mol at 25°C and the hypsochromic spectral shift for the dimer 1164 cm-1 (688 nm_ 637 nm) indicate a stack-like association of molecules and suggestpi-pi interactions between Pc macrocycles in dimer and higher aggregates, in contrast to hydrogen bonding between carboxylic groups of adjacent Pc molecules.

3

Addition of Diazomethane to Phosphonodithioformates and Reactions of Phosphonylated Thiocarbonyl S-Methylides

Urbaniak K., Mlostoń G., Gulea M., Masson S., Heimgartner H.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 9

1483-1494

EN

The reaction of phosphonodithioformates 14 with diazomethane at -60 graduate C yielded 2,5-dihydro-1,3,4-thiadiazoles 15 as unstable intermediates. Their structure was evidenced by the base-catalyzed elimination of methylsulfane leading to 1,3,4-thiadiazole- 2-phosphonates. At ca. -35 graduate C, thermal decomposition of 15 by N2-elimination led to reactive thiocarbonyl S-methylides 17. In the absence of trapping reagents, these 1,3-dipoles undergo a head-to-head dimerization leading to 1,4-dithianes 18. An intermediate zwitterionic dimer 19 was detected by 31P NMR spectroscopy. The initially formed thiocarbonyl S-methylide 17 as well as an open-chain zwitterionic dimer 20 was intercepted by methanol. Stable interception products were also obtained with S- and N-nucleophiles.

4

Anodic Oxidation of Trolox in Aqueous Solutions

Małyszko J., Mechanik M.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 9

1575-1582

EN

Electrochemical oxidation of trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) was investigated on glassy carbon (GC) electrodes in buffered aqueous solutions in the pH range of 1.0-8.8. The results were interpreted in terms of the formation of phenoxyl radicals, and their subsequent dimerization (radical-radical coupling, i.e. DIM1). Dimerization rate constants were estimated from peak heights. pKa value of the carboxyl group was determined by potentiometric acid/base titration.

5

Korelacje stałych podziału i dimeryzacji kwasu 2-chlorobenzoesowego z niektórymi parametrami fizykochemicznymi alkoholi alifatycznych

Zapała L., Kalembkiewicz J.

Zeszyty Naukowe Politechniki Rzeszowskiej. Chemia

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2002

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z. 18 [194]

87-93

PL

Na podstawie badań własnych i danych literaturowych analizowano zależności stałych podziału Kp i stałych dimeryzacji Kd kwasu 2-chlorobenzoesowego w układach dwufazowych od niektórych parametrów fizykochemicznych alkoholi alifatycznych. Stwierdzono, że wraz ze wzrostem gęstości alkoholu, refrakcji molowej, temperatury topnienia i temperatury wrzenia rośnie wartość stałej dimeryzacji Kd, a maleje wartość stałej podziału Kp kwasu. Zwiększenie natomiast parametru rozpuszczalności Hildebranda oraz stałej dielektrycznej alkoholu wywołuje wzrost wartości stałej podziału Kp i obniżenie wartości stałej dimeryzacji Kd.

EN

The dependences of distribution constants (Kp) and dimerization constants (Kd) of 2-chlorobenzoic acid in the diphasic systems on some physico-chemical properties of the alifatic alcohols on the base on the own and literature date were determined. It was found that the value of the dimerization constant Kd increases with an increase of density of the alkohol, molar refraction, melting point and boiling point, whereas the value of the partition constant Kp of the acid decreases following the same trends of the parameters. In case when Hildebrand solubility parameter and dielectric constant of alcohol increase the value of the partition constant Kp increases, whereas the value of dimerization constant Kd of acid decreases.

6

IR ni(OH) band and Dimerization of Phosphorus Acids in the Gas Phase and Solid State

Asfin R., G.S. Denisov G. S., D.N. Poplevchenkov D. N., Tokhadze K. G., Velikanova T.V.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 9

1223-1231

EN

The infrared absorption spectra of phosphorus acids R2POOH (R _ H,CH3, CH2Cl,CH2I, C6H5, C3F7, CH3O, C4H9O) have been recorded in the gas phase and in the solid state in the range 4000-1000 cm-1. The equilibrium between monomers and dimers of R2POOH was studied in the gas phase between 400-650 K. The broad absorption band of the _(OH) stretching vibration of the cyclic dimer in the region 3600-900 cm-1 is registered in the gas phase spectra at 400-600 K and in thin films spectra at 90-300 K. In all cases the band has the characteristic ABC structure, typical for spectra of complexes with strong hydrogen bond in the crystal phase and solution. The intensity and the first and second spectral moments of this band were determined. It was found that, on passing from thin films at low temperature to the gas phase at high temperature, the redistribution of intensity from the low frequency wing to the high frequency wing takes place. Despite significant differences of dimerization enthalpies (20-60 kcal/mole), the spectra of all acids have similar structure and close values of spectral moments, although the values of intensities are different.

7

Acyclonucleosides of indazole and their rearrangements

Boryski J.

Polish Journal of Chemistry

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1999

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vol. 73 nr 6

1019-1027

EN

2-[(2-Acetoxyethoxy)methyl]indazole (3), a kinetic product formed in the reaction of indazole (1) with 2-acetoxyethyl acetoxymethyl ether (2), undergoes an irreversible, acid-catalyzed isometrization of the 2Ž 1 transglycosylation type to the respective 1-regioisomer (4). In contrast to the purine acyclonucleosides series, however, product 4 undergoes a further rearrangement to the dimmer 5. On the basis of products distribution and kinetics of their formation, a mechanism of these conversions has been proposed and compared to the facile anomerization reactions of indazole ribofuranosides.

8

A post Hartree-Fock Quantum-Chemical Study of the Dimerization of 2-Pyrrolidinone

Gorb L., Jadżyn J., Wojciechowski K.

Polish Journal of Chemistry

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1999

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Vol. 73, nr 9

1549-1554

EN

Results of an ab initio post Hartree-Fock study of the molecular structure, the relative stability, and the dipole moment of the hydrogen-bonded 2-pyrrolidinone dimers are reported.

9

Crystal structure of meso-4,4'-Di[2.2]paracyclophane

Jones P.G., Kuś P.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 6

1106-1111

EN

Of the two possible racemates formed on the dimerization of [2.2]paracyclophane, the title compound C32H30 is the meso (RS/SR) isomer. It crystallizes in moniclinic system in space group P2-1/n with Z=4 and unit cell dimensions: a=13.7612(12), b= 11.2530(10), c=14.6974(12) A, beta=99.668(8)degree (at-100degree C). The conformation is described by interplanar angle between the linked rings, 48.67(8)degree. Some widened angles in the region of C4-C4' may indicate steric congestion.