TY - JOUR
T1 - Effect of transition metal substitution on the charge-transfer phase transition and ferromagnetism of dithiooxalato-bridged hetero metal complexes, (n-C3H7)4N[FeII 1-xMnII xFeIII(dto)3]
AU - Enomoto, Masaya
AU - Ida, Hiromichi
AU - Okazawa, Atsushi
AU - Kojima, Norimichi
N1 - Funding Information:
In contrast to such a substitution effect on the CTPT, the ferromagnetic phase was observed in the whole range of x for (n-C3H7)4N[Fe1–xIIMnxIIFeIII(dto)3], while it disappears above x = 0.83 for Crystals 2018, 8, x FOR PEER REVIEW 13 of 17 an enhancement of TC is caused by the increment of the high-temperature phase with the higher TC, whichoriginatesThe difinferenthecsuppre betwessioneen tofhe MntheCIITaPndT. ZnII-substituted complexes is based on the magnetic The difference betweeInI the MnIIIII and ZnII-substitutedII complexes is based on the magnetic II interaction between MII and FeIII. In the case of the ZnII-subIsI tituted IcIIomplex, the nonmagnetic ZnII prevents the ferromagnetic inIItIeracIItionIIIbetween the FeII and FeIII and induces anII antiferromagnetic exchange pathway of FeIII-ZInIIII-FeIII tIIhI rough the medium of nonmagnetic ZnII. The antiferromagnIIetic III interaction between FeIII and FeIII compensates for the ferromagnetic interaction between FeII and FeIII temperature rapidly increases with increasing x. On the other hand, in the case of the Mn -substituted temperature rapidly increasesIIwitIhII increasingIIx. OIIIn the other hand, in the case of the MnII-substituted complex, both the FeII-FeIII and MnII-FeIII magnetic interactions are ferromagnetic, which is responsible II for the positive Weiss temperature in the whole range of x, in contrast to the ZnII-substituted complexes, which is due to the substitution of the magnetic ions. Author Contributions: Conceptualization, M.E.; methodology, M.E.; validation, M.E., H.I., A.O. and N.K.; formal analysis, H.I. and A.O.; investigation, M.E. and N.K.; resources, M.E.; data curation, H.I., A.O. and M.E.; writing—original draft preparation, M.E.; writing—review and editing, A.O. and N.K.; visualization, M.E.; M.E.; swurpiteirnvgi—sioonr,igMin.Eal.;dprraofjtepctr eapdamraintiiosntr,aMtio.En.,; Mwr.Eit.i;n fgu—ndreinvgie awcqaunidsietidointi,nMg,.EA..O. and N.K.; visualization, M.E.; supervision, M.E.; project administration, M.E.; funding acquisition, M.E. Funding: This research was funded by a Grant-in-Aid for Young Scientists (No. 19750105) from the Ministry of Funding: This research was funded by a Grant-in-Aid for Young Scientists (No. 19750105) from the Ministry of Education, Culture, Sports, Science and Technology, Japan. Education, Culture, Sports, Science and Technology, Japan. Conflicts of Interest: The authors declare no conflict of interest.
Publisher Copyright:
© 2018 by the authors.
PY - 2018/12
Y1 - 2018/12
N2 - The dithiooxalato-bridged iron mixed-valence complex (n-C3H7)4N[FeIIFeIII(dto)3] (dto = dithiooxalato) undergoes a novel charge-transfer phase transition (CTPT) accompanied by electron transfer between adjacent FeII and FeIII sites. The CTPT influences the ferromagnetic transition temperature according to the change of spin configuration on the iron sites. To reveal the mechanism of the CTPT, we have synthesized the series of metal-substituted complexes (n-C3H7)4N[FeII 1-xMnII xFeIII(dto)3] (x = 0-1) and investigated their physical properties by means of magnetic susceptibility and dielectric constant measurements. With increasing MnII concentration, x, MnII-substituted complexes show the disappearance of CTPT above x = 0.04, while the ferromagnetic phase remains in the whole range of x. These results are quite different from the physical properties of the ZnII-substituted complex, (n-C3H7)4N[FeII 1-xZnII xFeIII(dto)3], which is attributed to the difference of ion radius as well as the spin states of MnII and ZnII.
AB - The dithiooxalato-bridged iron mixed-valence complex (n-C3H7)4N[FeIIFeIII(dto)3] (dto = dithiooxalato) undergoes a novel charge-transfer phase transition (CTPT) accompanied by electron transfer between adjacent FeII and FeIII sites. The CTPT influences the ferromagnetic transition temperature according to the change of spin configuration on the iron sites. To reveal the mechanism of the CTPT, we have synthesized the series of metal-substituted complexes (n-C3H7)4N[FeII 1-xMnII xFeIII(dto)3] (x = 0-1) and investigated their physical properties by means of magnetic susceptibility and dielectric constant measurements. With increasing MnII concentration, x, MnII-substituted complexes show the disappearance of CTPT above x = 0.04, while the ferromagnetic phase remains in the whole range of x. These results are quite different from the physical properties of the ZnII-substituted complex, (n-C3H7)4N[FeII 1-xZnII xFeIII(dto)3], which is attributed to the difference of ion radius as well as the spin states of MnII and ZnII.
KW - 57fe mössbauer spectroscopy
KW - Charge-transfer phase transition
KW - Dielectric response
KW - Dithiooxalato ligand
KW - Ferromagnetism
KW - Hetero metal complex
KW - Iron mixed-valence complex
KW - Substitution of 3d transition metal ion
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U2 - 10.3390/cryst8120446
DO - 10.3390/cryst8120446
M3 - Article
AN - SCOPUS:85064742623
SN - 2073-4352
VL - 8
JO - Crystals
JF - Crystals
IS - 12
M1 - 446
ER -