Homopiperazine Pt(II) adducts with DNA bases and nucleosides: Crystal structure of [PtII(homopiperazine)(9-ethylguanine)2](NO3)2

Synthesis of New Homopiperazine-1.4-Diium Tetrachloridromercurate (II) Monohydrate (C5H14N2)[HgCl4]·H2O, Crystal Structure, Hirshfeld Surface, Spectroscopy, Thermal Analysis, Antioxidant Activity, Electric and Dielectric Behavior

Using acid–base assays and simple slow evaporation method at ambient temperature, we were successful in producing a novel salt with the chemical formula (C5H14N2)[HgCl4]·H2O. According to single-crystal X-ray diffraction data, the crystal packing was regulated by H-bonds and by Coulomb interactions (also called electrostatic interactions) between distinct entities, which formed a 3D network. The 2D fingerprint plots and the Hirshfeld surface were utilized to examine the effect of intermolecular interactions. FTIR spectroscopy, PL spectroscopy, thermal analysis, and electrical conductivity experiments were also carried out, and the antioxidant activity was tested.

Homopiperazine (Hexahydro-1,4-diazepine)

The X-ray structure of the title compound has been determined for the first time. Data on its 1H–13C-NMR coupling constants and 15N-NMR spectrum are also given.

Effect of the Metal Ion on the Enantioselectivity and Linkage Isomerization of Thiosemicarbazone Helicates

The effect of the metal ion and ligand design on the enantioselectivity and linkage isomerization of neutral cobalt and zinc bisthiosemicarbazone metallohelicates has been investigated in this work. The electrochemical synthesis has afforded the enantioselective formation of chirally pure cobalt helicates, and the ΛΛ isomer of a single enantiomer has been crystallized as only product for the cobalt methyl-substituted thiosemicarbazone helicate. Interestingly linkage isomers have been formed from zinc ethyl-substituted thiosemicarbazone helicate enantiomers for the first time. The co-existence of these isomers has been evaluated from the point of view of both experimental results and computational calculations.

Platinum-DNA interactions and subsequent cellular processes controlling sensitivity to anticancer platinum complexes

Platinum-based compounds are widely used as chemotherapeutics for the treatment of a variety of cancers. The anticancer activity of cisplatin and other platinum drugs is believed to arise from their interaction with DNA. Several cellular pathways are activated in response to this interaction, which include recognition by high-mobility group and repair proteins, translesion synthesis by polymerases, and induction of apoptosis. The apoptotic process is regulated by activation of caspases, p53 gene, and several proapoptotic and antiapoptotic proteins. Such cellular processing eventually leads to an inhibition of the replication or transcription machinery of the cell. Deactivation of platinum drugs by thiols, increased nucleotide excision repair of Pt-DNA adducts, decreased mismatch repair, and defective apoptosis result in resistance to platinum therapy. The differences in cytotoxicity of various platinum complexes are attributed to the differential recognition of their adducts by cellular proteins. Cisplatin and oxaliplatin both produce mainly 1,2-GG intrastrand cross-links as major adducts, but oxaliplatin is found to be more active particularly against cisplatin-resistant tumor cells. Mismatch repair and replicative bypass appear to be the processes most likely involved in differentiating the molecular responses to these two agents. This review describes the formation of Pt-DNA adducts, their interaction with cellular components, and biological effects of this interaction.

The synthesis, crystal structure and spectroscopic properties of luminescent Zn(II) complex

A luminescent Zn(II) complex 1, ZnL2Cl2.2H2O has been synthesized where L=2,2',2''-(1,3,5-benzenetriyltrimethylidyne) as a yellow crystal. Single crystal X-ray analysis of the compound 1 shows a distorted tetrahedral structure. The compound 1 crystallizes in monoclinic, space group C2/c with a = 20.3151(19), b = 8.7299(9), c = 24.626(2) angstroms, beta = 107.474(2) degrees , V = 4165.9(7) A3. At room temperature, the complex 1 exhibits an intense blue emission at 474 nm upon 380 nm excitation.

Pentadentate thiosemicarbazones as versatile chelating systems. A comparative structural study of their metallic complexes

We have prepared some transition and post-transition metal complexes derived from the pentadentate thiosemicarbazone ligand bis(4-N-ethylthiosemicarbazone)-2,6-diacetylpyridine H(2)L(Et), by both chemical and electrochemical procedures. The complexes have been synthesised and fully characterised, including the crystal structures for the ligand H(2)L(Et) and its manganese, cadmium and lead complexes. We have also performed multinuclear (109)Ag, (113)Cd, (119)Sn and (207)Pb studies for silver, cadmium, tin and lead compounds, respectively. Moreover we present here a comparative study on the different structures found for pentadentate thiosemicarbazonate complexes, trying to check the influence of different factors, such as experimental procedure, size of metal, structure of the ligand, and metal oxidation state, on the final structure of the complex formed. Our aim is gaining a better insight into the coordination trends of pentadentate thiosemicarbazone ligands.