Accurate determination of the spin Hamiltonian parameters in transition-metal complexes with large zero-field splitting (ZFS) is an actual challenge in studying magnetic and spectroscopic properties of high-spin transition metal complexes. Recent critical papers have convincingly shown that previous determinations of these parameters, based only on the magnetic data, have low accuracy and reliability. A combination of X-band electron paramagnetic resonance (EPR) spectroscopy and SQUID magnetometry seems to be a more convincing and accurate approach. However, even in this case, the accuracy of the determination of the spin Hamiltonian parameters is strongly limited. In this work, we propose a purely spectroscopic approach, in which three complementary EPR spectroscopic techniques are used to unambiguously with high accuracy determine the spin Hamiltonian parameters for transition-metal complexes with S = 3/2. The applicability of this approach is demonstrated by analyzing the new quasi-octahedral high-spin Co(II) complex [Co(hfac) 2 (bpy)] (I). Along with the conventional X-band EPR spectroscopy, we also use such advanced techniques as multi-high-frequency EPR spectroscopy (MHF-EPR) and frequency-domain Fouriertransform THz-EPR (FD-FT THz-EPR). We demonstrate that the experimental data derived from the X-band and MHF-EPR EPR spectra allow determination of the g tensor (g x = 2.388, g y = 2.417, g z = 2.221) and the ZFS rhombicity parameter E/D = 0.158. The axial ZFS parameter D = 37.1 cm −1 is measured for I with the aid of FD-FT THZ-EPR spectroscopy, which is able to detect the high-energy EPR transition between the two Kramers doublets. CASSCF/NEVPT2 quantum-chemical calculations of magnetic parameters and magnetic direct current (dc) measurements are performed as well as testing options, and the results obtained in these ways are in good agreement with those derived using the proposed spectroscopic approach.

A new copper(ii) complex (I) was obtained by the reaction of a sterically crowded 2,4-di-(tert-butyl)-9-chloro-benzo[5,6][1,4]oxazine[2,3-b]phenoxazine bridging ligand with Cu(ii) hexafluoroacetylacetonate.

This article is dedicated to a comprehensive analysis of the data of the Seventh Census in China, conducted in 2020 and to the identification of the most important demographic and socioeconomic trends in the development of the population of the People’s Republic of China. The relevance of this study is due to the impact that demographic changes have on the world’s largest economy. Given the current high level of globalization and the scale of the PRC population, any risks and threats of a demographic nature have a direct impact not only on China’s security but potentially on the situation in the Asia–Pacific region and the world as a whole. The practical significance of this work for Russia is obvious, in particular, from the point of view of improving the migration policy of the Russian Federation. This study is based on a large array of statistical data, including from the PRC National Bureau of Statistics. The quantitative and qualitative changes in the Chinese population are analyzed, including the ratio of birthrates, mortality, natural increase and fertility, gender and age imbalances, and internal migration.

Triplet phosphinidenes, which have been postulated as important intermediates in numerous organophosphorus reactions, have been previously directly observed only in isolated cases. Recently we have published the first recorded EPR...