Magnetocaloric properties of manganese(III)porphyrins bearing 2,6-di-tert-butylphenolgroups

Korolev, V.V.; Lomova, T.N.; Maslennikova, A.N.; Korolev, D.V.; Shpakovsky, D.B.; Jianwei, Z.; Milaeva, E.R.

Авторы: Korolev V.V., Lomova T.N., Maslennikova A.N., Korolev D.V., Shpakovsky D.B., Jianwei Zhang, Milaeva E.R.
Журнал: Journal of Magnetism and Magnetic Materials
Том: 401
Год издания: 2016
Издательство: Elsevier BV
Местоположение издательства: Netherlands
Первая страница: 86
Последняя страница: 90
DOI: 10.1016/j.jmmm.2015.10.014
Аннотация: Magnetocaloric effect(MCE)and heat capacity during the magnetization of (5,10,15,20-tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphynato)manganese(III)chloride(1),(5-(4-hydroxyphenyl)-10,15,20-tris(3,5-di-tert-butyl-4-hydroxyphenyl)porphynato)manganese(III)chloride(2), and(5-(4-palmitoy-loxyphenyl)-10,15,20-tris(3,5-di-tert-butyl-4-hydroxyphenyl)porphynato)manganese(III)chloride(3)in their aqueous suspensions were determined by the microcalorimetric method over the temperature range of 278–320 K and in magnetic fields from 0 to 1 T. MCE was positive for all complexes studied,i.e.the magnetic field impression under adiabatic conditions led to an increase in temperature of the complexes suspensions.MCE increased with an increase in themagnetic field induction at all temperatures studied. Dependences of MCE on temperature had weak maxima at 298 K at all magnetic induction values. The disturbance of the intermolecular hydrogen-bonding of hydroxyl groups is one of probable reasons for such dependences type. MCE values increased under the palmitoyl substituent incorporation into one of the phenol groups at all temperatures. The heat capacity of the studied complexes roses lightly with temperature growth. Dependences of the heat capacity on temperature showed that the magnetic component of the heat capacity did not appear due to the presence of the manganese atom acting as a paramagnetic center in complexes 1,2,and 3. The relation between the complexes structure and their magnetothermal properties was analyzed. It was justified that the changes of magnetothermal properties were caused by electronic substitution effects and,to an even greater degree,by the conditions of intermolecular hydrogen bonds formation in the paramagnetic materials.
Добавил в систему: Шпаковский Дмитрий Борисович

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Magnetocaloric properties of manganese(III)porphyrins bearing 2,6-di-tert-butylphenolgroupsстатья

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