Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co II 6 Co III 3 } and {Co II Co 4 III } mixed valent complexes and a study of their magnetic properties

We are reporting two new mixed valent Co(ii)/Co(iii) polynuclear complexes, {Co II 6 Co III 3 } and {Co II Co III 4 }, bearing different amount of Co(ii) ions in their cores, through the employment of the multidentate triethanolamine (teaH 3 ) ligand in different stoichiometric ratios. We present a...

Descripción completa

Detalles Bibliográficos
Publicado: 2015
Materias:
Ground state
Magnetic relaxation measurement
Magnetism
Magnetization
Magnetization reversal
Temperature distribution
Characteristic relaxation time
External magnetic field
Magnetostructural correlations
Mixed-valent complexes
Orbital contribution
Polynuclear complexes
Temperature dependence
Zero-field splitting parameters
Cobalt compounds
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14779226_v44_n5_p2390_Funes
http://hdl.handle.net/20.500.12110/paper_14779226_v44_n5_p2390_Funes
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_14779226_v44_n5_p2390_Funes
record_format dspace
spelling paper:paper_14779226_v44_n5_p2390_Funes2023-06-08T16:18:14Z Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co II 6 Co III 3 } and {Co II Co 4 III } mixed valent complexes and a study of their magnetic properties Ground state Magnetic relaxation measurement Magnetism Magnetization Magnetization reversal Temperature distribution Characteristic relaxation time External magnetic field Magnetostructural correlations Mixed-valent complexes Orbital contribution Polynuclear complexes Temperature dependence Zero-field splitting parameters Cobalt compounds We are reporting two new mixed valent Co(ii)/Co(iii) polynuclear complexes, {Co II 6 Co III 3 } and {Co II Co III 4 }, bearing different amount of Co(ii) ions in their cores, through the employment of the multidentate triethanolamine (teaH 3 ) ligand in different stoichiometric ratios. We present a complete picture of the magnetic behaviour of both complexes through a combined usage of the susceptibility, magnetization and X-band EPR data as well as broken-symmetry DFT calculations. Compound 1 shows an atypical spin-only behaviour, probably due to the presence of four and five coordinated Co(ii) sites as well as highly distorted six coordinated Co(ii) ions, promoting a high degree of orbital contribution quenching. Through the usage of a simplified exchange coupling scheme and relying on DFT based magneto-structural correlation we have been able to explain the observed diamagnetic ground state. Concerning compound 2, DC magnetic data supported by X-band EPR measurements suggest the existence of anisotropy with a zero-field splitting parameter D, at least in the range of 2-10 cm -1 . In agreement with this description, a slow relaxation of magnetization is observed after applying a small external magnetic field, under AC measurements. Field and temperature dependence of the characteristic relaxation time establishes a thermal barrier for magnetization reversal of about 25 cm -1 , which is in good agreement with the energy splitting of the |±1/2〉 and |±3/2〉 doublets established from static magnetic measurements. © The Royal Society of Chemistry 2015. 2015 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14779226_v44_n5_p2390_Funes http://hdl.handle.net/20.500.12110/paper_14779226_v44_n5_p2390_Funes
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Ground state
Magnetic relaxation measurement
Magnetism
Magnetization
Magnetization reversal
Temperature distribution
Characteristic relaxation time
External magnetic field
Magnetostructural correlations
Mixed-valent complexes
Orbital contribution
Polynuclear complexes
Temperature dependence
Zero-field splitting parameters
Cobalt compounds
spellingShingle Ground state
Magnetic relaxation measurement
Magnetism
Magnetization
Magnetization reversal
Temperature distribution
Characteristic relaxation time
External magnetic field
Magnetostructural correlations
Mixed-valent complexes
Orbital contribution
Polynuclear complexes
Temperature dependence
Zero-field splitting parameters
Cobalt compounds
Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co II 6 Co III 3 } and {Co II Co 4 III } mixed valent complexes and a study of their magnetic properties
topic_facet Ground state
Magnetic relaxation measurement
Magnetism
Magnetization
Magnetization reversal
Temperature distribution
Characteristic relaxation time
External magnetic field
Magnetostructural correlations
Mixed-valent complexes
Orbital contribution
Polynuclear complexes
Temperature dependence
Zero-field splitting parameters
Cobalt compounds
description We are reporting two new mixed valent Co(ii)/Co(iii) polynuclear complexes, {Co II 6 Co III 3 } and {Co II Co III 4 }, bearing different amount of Co(ii) ions in their cores, through the employment of the multidentate triethanolamine (teaH 3 ) ligand in different stoichiometric ratios. We present a complete picture of the magnetic behaviour of both complexes through a combined usage of the susceptibility, magnetization and X-band EPR data as well as broken-symmetry DFT calculations. Compound 1 shows an atypical spin-only behaviour, probably due to the presence of four and five coordinated Co(ii) sites as well as highly distorted six coordinated Co(ii) ions, promoting a high degree of orbital contribution quenching. Through the usage of a simplified exchange coupling scheme and relying on DFT based magneto-structural correlation we have been able to explain the observed diamagnetic ground state. Concerning compound 2, DC magnetic data supported by X-band EPR measurements suggest the existence of anisotropy with a zero-field splitting parameter D, at least in the range of 2-10 cm -1 . In agreement with this description, a slow relaxation of magnetization is observed after applying a small external magnetic field, under AC measurements. Field and temperature dependence of the characteristic relaxation time establishes a thermal barrier for magnetization reversal of about 25 cm -1 , which is in good agreement with the energy splitting of the |±1/2〉 and |±3/2〉 doublets established from static magnetic measurements. © The Royal Society of Chemistry 2015.
title Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co II 6 Co III 3 } and {Co II Co 4 III } mixed valent complexes and a study of their magnetic properties
title_short Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co II 6 Co III 3 } and {Co II Co 4 III } mixed valent complexes and a study of their magnetic properties
title_full Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co II 6 Co III 3 } and {Co II Co 4 III } mixed valent complexes and a study of their magnetic properties
title_fullStr Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co II 6 Co III 3 } and {Co II Co 4 III } mixed valent complexes and a study of their magnetic properties
title_full_unstemmed Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co II 6 Co III 3 } and {Co II Co 4 III } mixed valent complexes and a study of their magnetic properties
title_sort switching nuclearity and co(ii) content through stoichiometry adjustment: {co ii 6 co iii 3 } and {co ii co 4 iii } mixed valent complexes and a study of their magnetic properties
publishDate 2015
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14779226_v44_n5_p2390_Funes
http://hdl.handle.net/20.500.12110/paper_14779226_v44_n5_p2390_Funes
_version_ 1768545943696703488

Ejemplares similares