Ferromagnetic Exchange Coupling in Ni(II) Complexes with a Coordinated Boron‐Oxamido Radical: A Result of Spin State Transition

Abstract

A Ni(II) coordination complex 1 with a novel boron-oxamido radical ligand was synthesized and isolated. Reactions of 1 with N,N-dimethyl-4-pyridinamine (DMAP) and 4,4'-bpy resulted in 2 and 3, respectively, accompanied by the spin state transition from S = 1/2 to S = 3/2. Both 2 and 3 were isolated as stable crystals and characterized to feature an S = 3/2 spin state, with the S = 1 Ni(II) atoms ferromagnetically coupled with the ligand-centred radicals, by SQUID measurement and EPR spectroscopy. Complex 3 represents the first example of one-dimensional magnetic chain constructed by S = 3/2 Ni(II)-radical units.

Molecular Ferroelastic Induced by Mono‐/Double‐Protonation Strategy

“…Ferroelastics, as an important class of three ferroic materials, feature switchable spontaneous strain under applied stress, which have captured a lively interest in materials science and condensed matter physics since ferroelasticity was discovered in displacive‐type inorganic oxides such as Pb 3 (PO 4 ) 2 and Gd 2 (MoO 4 ) 3 . [ 1‐14 ] So far, many inorganic ferroelastics have already been intensively investigated and widely applied due to their advantages of good chemical stability, high hardness and reliable performance, including BiVO 4 , NdP 5 O 14 , PbZr 1− x Ti x O 3 , SrBi 2 Ta 2 O 9 , etc . [ 15‐21 ] As a beneficial supplement to inorganic ferroelastics, molecular ferroelastics with the advantages of environmental friendliness, mechanical flexibility, easy synthesis and biocompatibility have been increasing interest because they hold great prospects in flexible, wearable and intelligent electronic devices.…”