(EtN)[W(DAPBH)(CN)], the first pentagonal-bipyramidal W(III) complex with unquenched orbital angular momentum: a novel Ising-type magnetic building block for single-molecule magnets.

The first pentagonal-bipyramidal tungsten(III) complex (EtN)[W(DAPBH)(CN)] with a NO-type Schiff-base ligand and two apical cyanide groups was synthesized and characterized structurally and magnetically. The complex has a low-spin ( = 1/2) ground state and features unquenched orbital angular momentum = ±1 causing very strong Ising-type magnetic anisotropy.

Pentagonal-bipyramidal 4d and 5d complexes with unquenched orbital angular momentum as a unique platform for advanced single-molecule magnets: current state and perspectives.

This article overviews the current state and prospects of the concept of advanced single-molecule magnets (SMMs) based on low-spin ( = 1/2) pentagonal-bipyramidal (PBP) 4d and 5d complexes with unquenched orbital angular momentum. This approach is based on the unique property of PBP 4d and 5d complexes to cause highly anisotropic spin coupling of perfect uniaxial symmetry, -zizj - (xixj + yiyj), regardless of the local geometric symmetry. The M(4d/5d)-M(3d) exchange-coupled pairs in the apical positions of the PBP complexes produce Ising-type exchange interactions (|| > ||), which serve as a powerful source of uniaxial magnetic anisotropy of a SMM cluster.

[M(Hdapsc)]-[Cr(CN)] (M = Mn, Co) Chain and Trimer Complexes: Synthesis, Crystal Structure, Non-Covalent Interactions and Magnetic Properties.

Four new heterometallic complexes combining [M(Hdapsc)] cations with the chelating Hdapsc {2,6-diacetylpyridine-bis(semicarbazone)} Schiff base ligand and [Cr(CN)] anion were synthesized: {[M(Hdapsc)]Cr(CN)K(HO)(EtOH)}·1.2(HO), M = Mn () and Co (), {[Mn(Hdapsc)]Cr(CN)(HO)}Cl·HO () and {[Co(Hdapsc)]Cr(CN)(HO)}Cl·2EtOH·3HO (). In all the compounds, M(II) centers are seven-coordinated by NO atoms of Hdapsc in the equatorial plane and N or O atoms of two apical -CN/water ligands.

Spin-Crossover and Slow Magnetic Relaxation Behavior in Hexachlororhenate(IV) Salts of Mn(III) Complexes [Mn(5-Hal-sal323)][ReCl] (Hal = Cl, Br).

The cationic complexes of Mn(III) with the 5-Hal-sal323 (Hal = Cl, Br) ligands and a paramagnetic doubly charged counterion [ReCl] have been synthesized: [Mn(5-Cl-sal323)][ReCl] () and [Mn(5-Br-sal323)][ReCl] (). Their crystal structures and magnetic properties have been studied. These isostructural two-component ionic compounds show a thermally induced spin transition at high temperature associated with the cationic subsystem and a field-induced slow magnetic relaxation of magnetization at cryogenic temperature, associated with the anionic subsystem.

Magnetic behavior of the novel pentagonal-bipyramidal erbium(III) complex (EtNH)[Er(HDAPS)Cl]: high-frequency EPR study and crystal-field analysis.

We report the synthesis, crystal structure and magnetic properties of the new heptacoordinated mononuclear erbium(III) complex (EtNH)[Er(HDAPS)Cl] (HDAPS = 2,6-diacetylpyridine bis-(salicylhydrazone)) (1). The coordination polyhedron around the Er(III) ion features a slightly distorted pentagonal bipyramid formed by the pentagonal NO chelate ring of the HDAPS ligand in the equatorial plane and two apical chloride ligands. Detailed high-frequency/high-field electron paramagnetic resonance (HF-EPR) studies of 1 result in the precise determination of the crystal field (CF) splitting energies (0, 290 and 460 GHz) and effective -values of the three lowest Kramers doublets (KDs) of the Er(III) ion.