[en] The results of studies of weak spin-spin exchange interactions in binuclear copper(II) complexes with hydrazones based on saturated dicarbohydrazides in which the coordination polyhedra are connected by polymethylene spacers are generalised and systematically described

[en] In the interaction of norzooanemonin 1,3-dimethylimidazolium-4-carboxylate (1) with CuBr₂, two types of crystals form: purple [Cu(L)₂Br₂][CuBr₄][CuL₄] (2) and light blue [CuL₄][CuBr₃] (3). In the reaction of 1 with CoCl₂ in methanol, neutral complex Co(L)₂Cl₂ (4) forms. The thermal decomposition of complex 4 is studied. At the first stage of this decomposition, two equivalents of CO₂ remove in a range 218–275 °C, and then a two-phase removal of two equivalents of L and the formation of CoCl₂ occur.

[en] The electron paramagnetic resonance (EPR) spectra of triplet centers in detonation nanodiamonds (DNDs) and diamond single crystals of submicrometer size, synthesized from those DNDs at high pressures and temperatures, are studied. In the EPR spectra of DNDs, signals from negatively charged nitrogen- vacancy centers (NV)/sup(-) with a g factor of g₁ = 4.24 and multivacancies with g₂ = 4.00 are observed. The signals from (NV)/sup(-) centers disappear in the spectra of diamond single crystals, and a quintet signal with g = 4.00 is detected at the position of the signal from multivacancies. Analysis of the shape and position of the quintet’ lines showed that this ESR signal is due to the pairs of nitrogen substitution centers in diamond, separated from each other by distances not exceeding 0.7 nm, between which a strong exchange interaction takes place. A comparison of the experimental data and the simulation results allows determining the spin-Hamiltonian parameters of the exchange-coupled pairs of paramagnetic impurity nitrogen atoms.