Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co6IICo3III} and {CoIICo4III} mixed valent complexes and a study of their magnetic properties

Abstract

Controlling the CoII content in polynuclear systems: {CoII6CoIII3} and {CoIICo4III} mixed valent complexes with distinct magnetic behaviours is reported.

Autoren

Alejandro V Funes
Luca Carrella
Lorenzo Sorace
Eva Rentschler
Pablo Alborés

DOI

10.1039/c4dt03034f

eISSN

1477-9234

ISSN

1477-9226

Ausgabe der Veröffentlichung

5

Zeitschrift

Dalton Transactions

Sprache

en

Online publication date

2015

Paginierung

2390 - 2400

Status

Published online

Herausgeber

Royal Society of Chemistry (RSC)

Herausgeber URL

http://dx.doi.org/10.1039/c4dt03034f

Datum der Datenerfassung

2024

Titel

Switching nuclearity and Co(<scp>ii</scp>) content through stoichiometry adjustment: {CoII6CoIII3} and {CoIICo4III} mixed valent complexes and a study of their magnetic properties

Ausgabe der Zeitschrift

44

Datenquelle: Crossref

Abstract

We are reporting two new mixed valent Co(ii)/Co(iii) polynuclear complexes, {Co(II)6Co(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 (teaH3) 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 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 , 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.

Addresses

Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE (CONICET), Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina. albores@qi.fcen.uba.ar.

Autoren

Alejandro V Funes
Luca Carrella
Lorenzo Sorace
Eva Rentschler
Pablo Alborés

DOI

10.1039/c4dt03034f

eISSN

1477-9234

Externe Identifier

PubMed Identifier: 25537966

Open access

false

ISSN

1477-9226

Ausgabe der Veröffentlichung

5

Zeitschrift

Dalton transactions (Cambridge, England : 2003)

Sprache

eng

Medium

Print

Paginierung

2390 - 2400

Datum der Veröffentlichung

2015

Status

Published

Datum der Datenerfassung

2014

Titel

Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co(II)6Co(III)3} and {Co(II)Co4(III)} mixed valent complexes and a study of their magnetic properties.

Sub types

Journal Article

Ausgabe der Zeitschrift

44

Datenquelle: Europe PubMed Central

Abstract

We are reporting two new mixed valent Co(ii)/Co(iii) polynuclear complexes, {Co(II)6Co(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 (teaH3) 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 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 , 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.

Autoren

Alejandro V Funes
Luca Carrella
Lorenzo Sorace
Eva Rentschler
Pablo Alborés

Autoren-URL

https://www.ncbi.nlm.nih.gov/pubmed/25537966

DOI

10.1039/c4dt03034f

eISSN

1477-9234

Ausgabe der Veröffentlichung

5

Zeitschrift

Dalton Trans

Sprache

eng

Country

England

Paginierung

2390 - 2400

Datum der Veröffentlichung

2015

Status

Published

Datum, an dem der Datensatz öffentlich gemacht wurde

2015

Titel

Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co(II)6Co(III)3} and {Co(II)Co4(III)} mixed valent complexes and a study of their magnetic properties.

Sub types

Journal Article

Ausgabe der Zeitschrift

44

Datenquelle: PubMed

Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co6IICo3III} and {CoIICo4III} mixed valent complexes and a study of their magnetic properties

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