Six new Schiff-base complexes (1–6) with pseudohalido terminal ligands exhibits spin crossover or high spin state behaviour.

In this work, we describe synthesis of conjugates of betulinic acid with substituted triazoles prepared via Huisgen 1,3-cycloaddition. All compounds contain free 28-COOH group. Allylic bromination of protected betulinic acid by NBS gave corresponding 30-bromoderivatives, their substitution with sodium azides produced 30-azidoderivatives and these azides were subjected to CuI catalysed Huisgen 1,3-cycloaddition to give the final conjugates. Reactions had moderate to high yields. All new compounds were tested for their in vitro cytotoxic activities on eight cancer and two non-cancer cell lines. The most active compounds were conjugates of 3β-O-acetylbetulinic acid and among them, conjugate with triazole substituted by benzaldehyde 9b was the best with IC50 of 3.3 μM and therapeutic index of 9.1. Five compounds in this study had IC50 below 10 μM and inhibited DNA and RNA synthesis and caused block in G0/G1 cell cycle phase which is highly similar to actinomycin D. It is unusual that here prepared 3β-O-acetates were more active than compounds with the free 3-OH group and this suggests that this set may have common mechanism of action that is different from the mechanism of action of previously known 3β-O-acetoxybetulinic acid derivatives. Benzaldehyde type conjugate 9b is the best candidate for further drug development.

Four complexes with bidentate N,N-donors 2-(furan-2-yl)-5-(pyridin-2-yl)-1,3,4-oxadiazole (fpo) and 2-(pyridin-2-yl)-5-(thiophen-2-yl)-1,3,4-oxadiazole (pto) with general formula [M-(L) 2 (NCS) 2 ] (M = Co(II), L = fpo for (1); M = Co(II), L = pto for (2); M = Fe(II), L = fpo (3); M = Fe(II), L = pto (4)) are reported. Analysis and characterization of the samples was performed using standard physico-chemical techniques-elemental analysis, nuclear magnetic resonance, Fourier transform infrared spectroscopy, single-crystal X-ray diffraction. Magnetic properties for 1-4 revealed large magnetic anisotropy of Co(II) complexes, and AC susceptibility measurements confirmed their single-molecule magnetic behaviour. Furthermore, the theoretical calculations at DFT and CASSCF/NEVPT2 level of theory were exploited to better understand magnetism of these compounds.

The impact of the second coordination sphere on the magnetic properties of [Ln(NO3)3(H2O)3]·(18C6) compounds comprising co-crystallized 18-crown-6 ethers was investigated.