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The First Series of Heterometallic Ln III ‐V IV Complexes Based on Substituted Malonic Acid Anions: Synthesis, Structure and Magnetic Properties
Ist Teil von
European journal of inorganic chemistry, 2018-12, Vol.2018 (47), p.5075-5090
Erscheinungsjahr
2018
Link zum Volltext
Quelle
Wiley Online Library All Journals
Beschreibungen/Notizen
The reaction of VOSO
4
with K
2
cbdc (cbdc
2–
is cyclobutane‐1,1‐dicarboxylate anion) and Ln(NO
3
)
3
(Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, Lu) yielded 17 novel heterometallic Ln
III
‐V
IV
compounds comprising stable bis‐chelate units {V
IV
O(cbdc)
2
(H
2
O)}. Three structural types of compounds are formed depending on the nature of the rare‐earth metal: 1D polymers {[Ln(VO)(cbdc)
2
(H
2
O)
7
]
·
0.5[VO(cbdc)
2
]}
n
(structural type I) [Ln = La (
1
), Ce (
2
)], 3D polymers {[KLn(VO)
2
(cbdc)
4
(H
2
O)
9
]
·
3.5H
2
O}
n
(structural type II) [Ln = La (
3
), Ce (
4
), Pr (
5
), Nd (
6
), Sm (
7
), Eu (
8
), Gd (
9
), Tb (
10
), Dy (
11
), Ho (
12
)] comprising trinuclear units {LnV
2
}, and octanuclear complexes {[KLn(VO)
2
(cbdc)
4
(H
2
O)
11
]
·
2H
2
O}
2
(structural type III) [Ln = Y (
13
), Er (
14
), Tm (
15
), Yb (
16
), Lu (
17
)] containing dinuclear units {LnV}. Magnetic properties were investigated for all isolated compounds. The Gd
III
‐V
IV
compound has ferromagnetic and antiferromagnetic exchange interactions between isotropic V
IV
and Gd
III
ions. Calculations using the DFT method at the UB3LYP/6‐31G(d,p)/SDD level of theory were performed in order to explain the different nature of exchange interactions in two Gd
III
‐V
IV
pairs. The Yb
III
‐V
IV
complex displays single‐molecule magnet properties; the effective energy barrier was estimated at Δ
E
eff
/k
B
= 26 K. The magnetic properties of Ln
III
‐V
IV
compounds with heavy lanthanide ions (Ln
III
= Er, Tm, Yb) were rationalized in terms of crystal‐field calculations for Ln
III
ions.