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Kinetic, Spectroscopic and Magnetic Properties of 1,4,8,11-Tetraazacyclotetradecanenickel Bi- and Trivalent Complexes

100%

Banaś B. , Nahorska M. , Korybut-Daszkiewicz B. , Mroziński J.

tom Vol. 77 / nr 1

21-29

Nickel(II) and nickel(III) complexes of formula [NiIILCl2] and [NiIIILCl2]+ containing tetraaza macrocyclic ligands with nitrogen donor atoms, where L = [14]aneN4 (L1), 2-Me[14]aneN4 (L2), 5,12-Me2[14]aneN4(L3), 5,7,7,12,14,14-Me6[14]aneN4 (L4), form stable crystals with a pseudo-octahedral geometry of central atom. This work concerns the methyl analogues of Ni(II) and Ni(III) complexes. Magnetic and spectroscopic measurements gave values of spectroscopic parameter g and paramagnetic temperature dependence characteristic for this type of compounds. Their properties were investigated using EPR, reflectance spectroscopy and IR techniques. The Faraday method was used for the investigation of magnetic susceptibility between 4.2-300 K.

Stability and ESR Spectra of Ni(III) Tetraazamacrocyclic Complexes in Nitrate and Chloride Solutions

100%

Taraszewska J. , Sadło J. , Michalik J. , Korybut-Daszkiewicz B.

tom Vol. 74, nr 6

813-822

Complexes [NiIII(cyclam)Cl2]Cl (10, NiIII(cyclam)(NO3)2]lO4 (2) and [NiIII(2-methyl-cyclam)(NO3)2]ClO4 (3) were isolated and the stability of Ni(III) was studied by UV-VIS spectrophotometry as a function of NaCl and NaNO3 concentration. In complexes 2 and 3 the decay of Ni(III) followed the first order kinetics in aqueous and nitrate solutions up to 1 ol/dm3. In complex 1 the first order kinetics was observed only in aqueous and saturated NaCl solutions. With increase in NaNO3 concentration the stability of Ni(III) in complexes 2 and 3 increased however, in complex 3 it was lower than in complex 2. Stability of Ni(III) in complex 1 increased also with increasing NaCl concentration but it diminished starting from 2 mol/dm3 NaCl. The forms of complexes depending on the salt concentration were characterized by the ESR technique.

Formyl Group as a Source of AGIBA Effect in Mono-, Di- and Tri- Formylo Derivatives of Benzene

100%

Frączak B. T. , Krygowski T. M. , Cyrański M. K. , Korybut-Daszkiewicz B.

2008

tom Vol. 82, nr 10

1999-2007

Experimental geometry of 1,3,5-triformylobenzene and the optimized geometry of mono, meta- and para- diformylo - and 1,3,5-triformylo- benzene deriva tives were used for analysis of structural and energetic consequences of angular group induced bond alternation (AGIBA) effect of substituent. The effect is mostly observed by a substantial imbalance of the Kekulé structures of the ring in molecules in questions - the cis-type bonds in the ring in respect to CO bond in the formyl groups are al ways longer than the trans ones. Energetic differences between molecules with and with out AGIBA ef fects are rather small. Key words: substituent effect, pi-electron delocalization, canonical structures, AGIBA

New trends in the investigations of macro cyclic magnets

88%

Mroziński J. , Tomkiewicz A. , Nahorska M. , Skorupa A. , Korybut-Daszkiewicz B.

Materials Science

2003

tom Vol. 21, No. 2

161-170

Series of new type of copper(II), nickel(III) and rhenium(IV) macro cyclic complexes, are the newly investigated systems, having an important meaning as a macrocyclic magnets. Their magnetic measurements have been investigated over the temperature range 1.8 - 300°K using a Quantum Design SQUID magnetometer (MPMSxL - 5 type), indicated that all of them behave as a weakly interacting magnets.