A series of M^IICu^II₃ stars (M = Mn, Ni, Cu, Zn) exhibiting unusual magnetic properties

Author(s)

Suraj Mondal, Santanu Mandal, Luca M. Carrella, Arpita Jana, Michel Fleck, Andreas Köhn, Eva Rentschler, Sasankasekhar Mohanta

Abstract

The work in this report describes the syntheses, electrospray ionization mass spectromtery, structures, and experimental and density functional theoretical (DFT) magnetic properties of four tetrametallic stars of composition [MII(CuIIL)3](ClO4)2 (1, M = Mn; 2, M = Ni; 3, M = Cu; 4, M = Zn) derived from a single-compartment Schiff base ligand, N,N'-bis(salicylidene)-1,4-butanediamine (H2L), which is the [2 + 1] condensation product of salicylaldehyde and 1,4-diaminobutane. The central metal ion (MnII, NiII, CuII, or ZnII) is linked with two µ2-phenoxo bridges of each of the three [CuIIL] moieties, and thus the central metal ion is encapsulated in between three [CuIIL] units. The title compounds are rare or sole examples of stars having these metal-ion combinations. In the cases of 1, 3, and 4, the four metal ions form a centered isosceles triangle, while the four metal ions in 2 form a centered equilateral triangle. Both the variable-temperature magnetic susceptibility and variable-field magnetization (at 2-10 K) of 1-3 have been measured and simulated contemporaneously. While the MnIICuII3 compound 1 exhibits ferromagnetic interaction with J = 1.02 cm-1, the NiIICuII3 compound 2 and CuIICuII3 compound 3 exhibit antiferromagnetic interaction with J = -3.53 and -35.5 cm-1, respectively. Variable-temperature magnetic susceptibility data of the ZnIICuII3 compound 4 indicate very weak antiferromagnetic interaction of -1.4 cm-1, as expected. On the basis of known correlations, the magnetic properties of 1-3 are unusual; it seems that ferromagnetic interaction in 1 and weak/moderate antiferromagnetic interaction in 2 and 3 are possibly related to the distorted coordination environment of the peripheral copper(II) centers (intermediate between square-planar and tetrahedral). DFT calculations have been done to elucidate the magnetic properties. The DFT-computed J values are quantitatively (for 1) or qualitatively (for 2 and 3) matched well with the experimental values. Spin densities and magnetic orbitals (natural bond orbitals) correspond well with the trend of observed/computed magnetic exchange interactions.

Organisation(s)

Department of Mineralogy and Crystallography

External organisation(s)

Universität Stuttgart, University of Calcutta, Bankura Christian College, Johannes Gutenberg-Universität Mainz

Journal

Inorganic Chemistry

Volume

54

Pages

117-131

No. of pages

15

ISSN

0020-1669

Publication date

12-2014

Peer reviewed

Yes

Austrian Fields of Science 2012

105113 Crystallography, 104011 Materials chemistry, 104022 Theoretical chemistry

Portal url

https://ucrisportal.univie.ac.at/en/publications/a-series-of-miicuii3-stars-m--mn-ni-cu-zn-exhibiting-unusual-magnetic-properties(f06c97b1-8e63-43dd-8033-7fe7e1d85f57).html