Maxim A. Faraonov

Two axial anionic Dy complexes with the open form of a photochromic spirooxazine and TBA ⁺ or Cp* ₂ Co ⁺ cations were obtained. Both complexes are a single-ion magnets with a high U _eff of 680–750 cm ⁻¹ and T _b = 6 K. One of them is photoresponsive.

A series of crystalline ring-reduced Pc-based V ^IV , Cu ^II , and Sn ^II complexes has been synthesized, providing insight into the structural, electronic, and magnetic properties and highlighting their potential for spin-based applications.

A series of anionic bi- and trinuclear complexes of Co ^II , Fe ^II , and Mn ^II with hexaazatrinaphthylene (HATNA) and hexaazatriphenylenehexacarbonitrile (HAT(CN) ₆ ), incorporating paramagnetic Cp* ₂ Fe ⁺ cations ( S = 1/2), were obtained and investigated.

Reduced tetra(4-pyridyl)porphyrins (H ₂ TPyP and Cu ^II TPyP) form polymers with M ^III (TMHD) ₃ (M = Dy, Tb and Gd). Folded zigzag 2D and linear 1D polymers are obtained. Their structure, optical and magnetic properties are investigated.

Interaction of fullerene C₆₀ with Cs₂Fe(CO)₄ in the presence of two equivalents of tetrabutylammonium iodide (TBAI) yields the first dianionic coordination complex of fullerene: (TBA⁺)₂{[Fe₂(CO)₆]-η²,η²-C₆₀}^2– (1). According to magnetic data and DFT calculations, complex 1 has a diamagnetic ground (S = 0) and a triplet excited state (S = 1) populated above 80 K. As a result, a new broad EPR signal appears, whose integral intensity grows with temperature; the estimated singlet–triplet energy gap is 508 ± 8 K. The broad signal attributed to the triplet has g = 2.0046 with a line width of 5.6 mT at 140 K, and this signal is shifted to smaller g-factors (2.0000) and narrows as the temperature increases. Calculations also show that the singlet–triplet gap is defined by the positions of the cations close to the Fe₂(CO)₆ fragment or the fullerene cage. According to DFT calculations, the negative electron density is mainly localized on the fullerene cage (−1.051) in the singlet state, and this charge even increases to −1.204 in the triplet state of the complex. Spin density localized on Fe₂(CO)₆ is concentrated on only one of the two iron atoms.