Slow magnetic relaxation in penta-coordinate cobalt(II) field-induced single-ion magnets (SIMs) with easy-axis magnetic anisotropy

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989592%3A15310%2F20%3A73604488" target="_blank" >RIV/61989592:15310/20:73604488 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.rsc.org/en/content/articlepdf/2020/dt/d0dt02338h" target="_blank" >https://pubs.rsc.org/en/content/articlepdf/2020/dt/d0dt02338h</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/d0dt02338h" target="_blank" >10.1039/d0dt02338h</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Slow magnetic relaxation in penta-coordinate cobalt(II) field-induced single-ion magnets (SIMs) with easy-axis magnetic anisotropy

Popis výsledku v původním jazyce

Two penta-coordinate complexes of the general formula [Co(L-n)(NCS)]ClO4, where L-1= {bis[(3,5-dimethyl-1H-pyrazol-1-yl)ethyl]-[(3,4-dimethoxypyridin-2-yl)methyl]}amine and L-2= {bis[(3,5-dimethyl-1H-pyrazol-1-yl)ethyl]-[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]}amine, have been synthesized and thoroughly characterized. Each of the cobalt(ii) atoms is penta-coordinated in the {CoN5} donor set with a distorted square-pyramidal geometry in [Co(L-1)(NCS)]ClO4 center dot MeOH (1), while the vicinity of the central atom can be described as a distorted trigonal-bipyramidal geometry in [Co(L-2)(NCS)]ClO4(2) as revealed using the SHAPE analysis. Differences in interatomic parameters among the cobalt(ii) and donor atoms in 1 and 2 have definite impact on the magnetic features of both compounds. The complexes show an easy-axis magnetic anisotropy (D = -38.5 cm(-1) for 1 and D= -8.5 for 2), and both complexes reveal a large rhombicity with E/D = 0.21 for 1 and E/D = 0.29 for 2. The ZFS parameters (g, D and E) were also calculated using CASSCF/NEVPT2 methods and they are in good agreement with those determined from experimental data. A frequency dependent out-of-phase susceptibility has been observed in external magnetic field (B-dc= 0.1 T) revealing the following parameters of slow relaxation of magnetization for 1: energy of the spin reversal barrier, U-eff = 16.0 cm(-1)(U-eff/kB = 23.0 K) and the relaxation time, tau(0)= 1.28 x 10(-6)s. In the case of complex 2, no maxima of frequency dependent out-of-phase susceptibility have been observed and thus, the value of U-eff= 17 cm(-1) has been estimated using the expression U-eff = vertical bar D vertical bar x (S-2- 1/4). It has been demonstrated that the degree of substitution and the type of substituents on the pyridyl moieties of the tripodal ligands (L-1 and L-2) used in these penta-coordinate cobalt(ii) complexes have significant impact on structural and magnetic features.

Název v anglickém jazyce

Slow magnetic relaxation in penta-coordinate cobalt(II) field-induced single-ion magnets (SIMs) with easy-axis magnetic anisotropy

Popis výsledku anglicky

Two penta-coordinate complexes of the general formula [Co(L-n)(NCS)]ClO4, where L-1= {bis[(3,5-dimethyl-1H-pyrazol-1-yl)ethyl]-[(3,4-dimethoxypyridin-2-yl)methyl]}amine and L-2= {bis[(3,5-dimethyl-1H-pyrazol-1-yl)ethyl]-[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]}amine, have been synthesized and thoroughly characterized. Each of the cobalt(ii) atoms is penta-coordinated in the {CoN5} donor set with a distorted square-pyramidal geometry in [Co(L-1)(NCS)]ClO4 center dot MeOH (1), while the vicinity of the central atom can be described as a distorted trigonal-bipyramidal geometry in [Co(L-2)(NCS)]ClO4(2) as revealed using the SHAPE analysis. Differences in interatomic parameters among the cobalt(ii) and donor atoms in 1 and 2 have definite impact on the magnetic features of both compounds. The complexes show an easy-axis magnetic anisotropy (D = -38.5 cm(-1) for 1 and D= -8.5 for 2), and both complexes reveal a large rhombicity with E/D = 0.21 for 1 and E/D = 0.29 for 2. The ZFS parameters (g, D and E) were also calculated using CASSCF/NEVPT2 methods and they are in good agreement with those determined from experimental data. A frequency dependent out-of-phase susceptibility has been observed in external magnetic field (B-dc= 0.1 T) revealing the following parameters of slow relaxation of magnetization for 1: energy of the spin reversal barrier, U-eff = 16.0 cm(-1)(U-eff/kB = 23.0 K) and the relaxation time, tau(0)= 1.28 x 10(-6)s. In the case of complex 2, no maxima of frequency dependent out-of-phase susceptibility have been observed and thus, the value of U-eff= 17 cm(-1) has been estimated using the expression U-eff = vertical bar D vertical bar x (S-2- 1/4). It has been demonstrated that the degree of substitution and the type of substituents on the pyridyl moieties of the tripodal ligands (L-1 and L-2) used in these penta-coordinate cobalt(ii) complexes have significant impact on structural and magnetic features.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10402 - Inorganic and nuclear chemistry

Projekt

<a href="/cs/project/EF16_019%2F0000754" target="_blank" >EF16_019/0000754: Nanotechnologie pro budoucnost</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Dalton Transactions

ISSN

1477-9226

e-ISSN

—

Svazek periodika

49

Číslo periodika v rámci svazku

33

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

12

Strana od-do

11715-11726

Kód UT WoS článku

000563083800029

EID výsledku v databázi Scopus

2-s2.0-85088950474