Synthesis, structure, DNA/protein binding and in vitro cytotoxicity of new ruthenium metallates

Abstract

The reaction of [RuHCl(CO)(PPh 3 ) 3 ] with an equimolar amount of salicylaldehyde-4(N)-methylthiosemicarbazone [H 2 -(Sal-mtsc)] resulted in two entities, namely [Ru(H-Sal-mtsc)Cl(CO) (PPh 3 ) 2 ] (1) and [Ru(Salmtsc)(CO)(PPh 3 ) 2 ] (2) from a single tub. The new complexes were characterized by various spectro (IR, absorption and NMR), analytical and single crystal X-ray diffraction studies. From the crystallographic studies, it is confirmed that in complex 1, the ligand coordinated through the thiolate sulfur and the deprotonated hydrazinic nitrogen N(2), resulting in the formation of an unusual strained four membered chelate ring. The third potential donor, phenolic oxygen, remained uncoordinated. In complex 2, the ligand coordinated as an ONS chelate with the formation of more common five and six membered chelate rings. Complexes 1 and 2 have been tested for their DNA/protein binding properties by taking CT-DNA/lysozyme as models. From the protein binding studies, the alterations in the secondary structure of lysozyme by the ruthenium(II) complexes (1 and 2) were confirmed with synchronous and threedimensional fluorescence spectroscopic studies. The in vitro cytotoxicity of the newly-synthesized complexes was carried out in two different human tumour cell lines, A549 and HepG2. The cytotoxicity studies showed that complex 2 exhibited higher activity than 1. † Electronic supplementary information (ESI) available. CCDC 821302 for [Ru-(H-Sal-mtsc)(CO)Cl(PPh 3 ) 2 ]•CH 3 CN (1) and 821303 for [Ru(Sal-mtsc)(CO)(PPh 3 ) 2 ] (2). For ESI and crystallographic data in CIF or other electronic format see

A structural and biological study on the new 3,5-diacetyl-1,2,4-triazol bis(p-chlorophenylthiosemicarbazone) ligand and its bimetallic complexes

“…The observed hyperchromic effect suggests that both compounds bind to CT-DNA by external contact. 31 These characteristics are comparable to those previously reported for various neutral bis(thiosemicarbazone) palladium and platinum complexes and for which a non-covalent binding along outside of DNA helix surface (major or minor groove) was proposed. 24,32 In the UV region, H 5 L 1 and [Pt(µ-H 3 L 1 )] 2 exhibit, in DMSO:Tris buffer (2.5:100) mixture, intense absorption bands attributable to intraligand transitions which could be perturbed in the case of interaction with CT DNA.…”

Synthesis and structural and DNA binding studies of mono‐ and dinuclear copper(II) complexes constructed with ─O and ─N donor ligands: Potential anti‐skin cancer drugs

“…The quenching of emission in the absence and presence of DNA with constant concentration of copper(II) compounds 1 – 4 is shown in Figure . The spectra show that a greater DNA concentration leads to better quenching; the increasing emission intensity indicates the DNA binding tendency of the complex and stacking interaction between adjacent DNA base pairs . The binding affinity of 1 – 4 is in good accordance with the Stern–Volmer equation, which provides further evidence that the compounds bind to DNA.…”

Tailored molybdenum imido alkylidene N‐heterocyclic carbene complexes as latent catalysts for the polymerization of dicyclopentadiene

“…Because of the high costs for ruthenium, the tendency of Ru‐based catalysts to form colored decomposition products and the substantial cytotoxicity of Ru, alternative latent precatalysts, for example, based on group 6 metal alkylidenes appear highly desirable. Interestingly, very few reports exist on latent group 6‐based precatalysts .…”