The collection of Volodymyr Opanasovych Karawajew, stored at the Schmalhausen Institute of Zoology of the National Academy of Sciences of Ukraine (SIZK, Kiev), is one of the richest ant collections of the world. It contains more than 20,000 dry mounted specimens, collected mostly in Southeast Asia and the Palaearctic, as well as in the Afrotropics, Australia, and North and South America. Among them, we found type specimens of 509 taxa, described by Karawajew and other myrmecologists.
View Article and Find Full Text PDFThe first pentagonal-bipyramidal tungsten(III) complex (EtN)[W(DAPBH)(CN)] with a NO-type Schiff-base ligand and two apical cyanide groups was synthesized and characterized structurally and magnetically. The complex has a low-spin ( = 1/2) ground state and features unquenched orbital angular momentum = ±1 causing very strong Ising-type magnetic anisotropy.
View Article and Find Full Text PDFThis article overviews the current state and prospects of the concept of advanced single-molecule magnets (SMMs) based on low-spin ( = 1/2) pentagonal-bipyramidal (PBP) 4d and 5d complexes with unquenched orbital angular momentum. This approach is based on the unique property of PBP 4d and 5d complexes to cause highly anisotropic spin coupling of perfect uniaxial symmetry, -zizj - (xixj + yiyj), regardless of the local geometric symmetry. The M(4d/5d)-M(3d) exchange-coupled pairs in the apical positions of the PBP complexes produce Ising-type exchange interactions (|| > ||), which serve as a powerful source of uniaxial magnetic anisotropy of a SMM cluster.
View Article and Find Full Text PDFA series of six seven-coordinate pentagonal-bipyramidal (PBP) erbium complexes, with acyclic pentadentate [] Schiff-base ligands, 2,6-diacetylpyridine bis-(4-methoxybenzoylhydrazone) [HDAPMBH], or 2,6-diacethylpyridine bis(salicylhydrazone) [HDAPS], and various apical ligands in different charge states were synthesized: [Er(DAPMBH)(CHOH)Cl] (); [Er(DAPMBH)(HO)Cl]·2CHOH (); [Er(DAPMBH)(CHOH)Cl] (); [Er(DAPMBH)(CHOH)(N)] (); [(EtH)N][Er(HDAPS)Cl] (); and [(EtH)N][Y.Er.(HDAPS)Cl] ().
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