This study presents the novel hexacoordinated Co(ii) mononuclear complex with SIM behavior.

Herein, we report on synthesis and magnetic properties of Co(II) coordination compound with 1,1'-bis(1-((pyrid-2-ylmethylene)hydrazono)ethyl)ferrocene (L) ligand with general formula [CoLCl2]. The analysis of static magnetic data supported by the CASSCF/NEVPT2...

A new hexacoordinate Co(II) complex with the general formula [CoL(NCS) 2 ]•DMSO (1) (L = biscondensation product of diacetyl and 2-hydrazinyl-4,6-dimethylpyrimidine, DMSO = dimethylsulfoxide) exhibiting field-induced single-ion magnet (SIM) behavior has been obtained and characterized. To explain such field-induced SIM behavior, we have performed the analysis of the observed direct current (DC) magnetic properties based on the Griffiths Hamiltonian in combination with the highlevel quantum-chemical calculations of the crystal field parameters. The complex has been shown to exhibit strong easy-axis-type magnetic anisotropy arising from a large negative value Δ ax = −1538.0 cm −1 of the axial crystal parameter, which is accompanied by a weak rhombic contribution with |Δ rh | = 219.3 cm −1 . Magnetic properties of 1 have been compared with the previously studied field-induced SIM compound [CoLCl 2 ]•H 2 O (2). Introduction of a thiocyanide anion in 1 (instead of chloride in 2) in the Co(II) coordination sphere resulted in improvement of uniaxial magnetic anisotropy and switch of the relaxation process from the combination of direct and Raman mechanisms in 2 to Orbach-type one in complex 1. Effects of substitution of acidoligands in the Co(II) coordination sphere on the crystalline structure, DC magnetic properties, magnetic anisotropy, and magnetization relaxation processes have been rationalized.

The magnetic properties of a dinuclear copper(II) complex of the Schiff base ligand bis(N,N′‐3‐formylsalicylidene)‐1,3‐diaminopropan‐2‐ol (H3L) with an exogenous acetate bridging group, [Cu2L(CH3COO)] (2), and the product of its crystallization from dimethyl sulfoxide (DMSO) solution, [Cu2L(CH3COO)(DMSO)] (3), are studied experimentally and theoretically. The coordination of a DMSO molecule triggers exchange coupling from antiferromagnetic in 2 (2J = –94.8 cm–1) to ferromagnetic in 3 (2J = +121 cm–1). A combination of experimental data [XRD, X‐ray absorption spectroscopy (XAS)] and the results of DFT calculations with a broken‐symmetry approach show that the different magnetic behaviour of 2 and 3 is explained by a different conformation of the dinuclear unit, which is “symmetric” in 2 and roof‐shaped in 3. The role of the DMSO molecule in exchange‐coupling sign inversion is limited to the stabilisation of the roof‐shaped conformation of the complex.

A novel chelatofore functionalized spiropyran of the 2-oxaindane series, namely 8-formyl-7-hydroxy-3',3'-dimethylspiro[2H-chromene-2,1'(3'H)-2-benzofuran], C(19)H(16)O(4), is reported. In the crystalline state, dimers are formed as a result of the pi-pi stacking of aromatic groups of the 2H-chromene part of the molecule and C-H...O interactions. The C(spiro)-O bond length in the pyran ring is 1.4558 (10) A, which is longer than or equal to the bond length in thermo- and photochromic 2-oxaindane spiropyrans synthesized previously, except for the 7,8-benzo/6-NO(2) derivative, in which this bond length is 1.465 (2) A.