Chloranilato-Based Layered Ferrimagnets with Solvent-Dependent Ordering Temperatures

Abstract

We report the synthesis and the characterization of six new heterometallic chloranilato-based ferrimagnets formulated as (NBu4)[MnCr(C6O4Cl2)3]·nG with n = 1 for G = C6H5Cl (1), C6H5I (3), and C6H5CH3 (4); n = 1.5 for G = C6H5Br (2) and n = 2 for G = C6H5CN (5) and C6H5NO2 (6); (C6O4Cl2)2− = 1,3-dichloro,2,5-dihydroxy-1,4-benzoquinone dianion. The six compounds are isostructural and show hexagonal honeycomb layers of the type [MnCr(C6O4Cl2)3]− alternating with layers containing the NBu4+ cations. The hexagons are formed by alternating Mn(II) and Cr(III) connected by bridging bis-bidentate chloranilato ligands. The benzene derivative solvent molecules are located in the hexagonal channels (formed by the eclipsed packing of the honeycomb layers) showing π-π interactions with the anilato rings. The six compounds behave as ferrimagnets with ordering temperatures in the range 9.8–11.2 K that can be finely tuned by the donor character of the benzene ring and by the number of solvent molecules inserted in the hexagonal channels. The larger the electron density on the aromatic ring and the larger the number of solvent molecules are, the higher Tc is. The only exception is provided by toluene, where the formation of H-bonds might be at the origin of weaker π-π interactions observed in this compound.

Anilato‐Based Coordination Polymers with Slow Relaxation of the Magnetization: Role of the Synthetic Method and Anilato Ligand

“…[6] Another family of O-donor ligands that can be used to prepare Ln-containing CPs and MOFs are anilate-type ligands (dianions of 3,6-disubstituted-2,5-dihydroxy-1,4-benzoquinone derivatives = C 6 O 4 X 2 2À , Scheme 1a). [7] These ligands have extensively been used to prepare many complexes and lattices with transition metal ions with interesting magnetic and luminescent properties, [8][9][10][11][12][13][14][15][16] making them very appealing for the preparation of Ln-containing CPs and MOFs. Thus, these ligands contain two pairs of O atoms in ortho positions with a charge À 1 delocalized on each pair, which allows them to act as chelating bis-bidentate ligands connecting two metal ions (Scheme 1b).…”