Heterotrimetallic Ru(II)/Pd(II)/Ru(II) complexes: Synthesis, crystalstructure, spectral characterization, DFT calculation and antimicrobial study

•Mononuclear Ru(II) and heterotrimetallic Ru(II)–Pd(II)–Ru(II) complexes are synthesized.•The progress of the reactions was monitored by 31P{1H} NMR and FTIR.•The absorption spectrum was modeled by TD-DFT.•Heterotrimetallic complexes exhibit high antibacterial and antifungal a inhibitory activity.

New ruthenium(II) mononuclear complexes of the type [RuCl2(PPh3)2(η2-triamine)] (2) [RuCl(PPh3)2(η3-triamine)]Cl (5) (triemine = N1-(2-aminoethyl)-1,2-ethanediamine) have been synthesized by reacting [RuCl2(PPh3)3] (1) with one mole equivalent of N1-(2-aminoethyl)-1,2-ethanediamine in dichloromethane. Reaction of (2) with half-equivalent of (PhCN)2PdCl2 or Pd(OAc)2 in dichloromethane as a solvent afforded two novel heterotrimetallic Ru(II)–Pd(II)–Ru(II) complexes, [RuIICl2(PPh3)2(triamine)]2[PdIIX2](X = Cl, OAc) (3 and 4), bearing bioactive ligand. The progress of the undertaken reactions was monitored by 31P{1H} NMR and FTIR. Crystal structure of complex 2 was confirmed by X-ray diffraction. The absorption spectrum of 2 in dichloromethane was modeled by time-dependent density functional theory (TD-DFT). The in vitro antimicrobial studies of complex 2–5 against an array of microorganisms (bacteria and fungi) were conducted. Complexes 3 and 4 exhibit high dual antibacterial and antifungal activity inhibiting microorganisms possibly via hydrolytic pathway which further evidenced by electrochemical analyses. The complexes 3 and 4 show a high inhibitory activity at 200 μg/ml concentration, suggesting that complexes 3 and 4 are two efficient catalytic inhibitor of microorganisms and further, they should be tested against cancer strains.

Graphical abstractNew ruthenium(II) mononuculear complexes of the type [RuCl2(PPh3)2(η2-triamine)] (2) [RuCl(PPh3)2(η2-triamine)]Cl (5) (triemine = N1-(2-aminoethyl)-1,2-ethanediamine) have been synthesized by reacting [RuCl2(PPh3)3] (1) with one mole equivalent of N1-(2-aminoethyl)-1,2-ethanediamine in dichloromethane Reaction of (2) with half-equivalent of (PhCN)2PdCl2 or Pd(OAc)2 in dichlormethane as a solvent afforded heterotrimetallic Ru–Pd–Ru complexes, [RuIICl2(PPh3)2(triamine)]2[PdIIX2](X = Cl, OAc) (3 and 4). The progress of the undertaken reactions was monitored by 31P{1H} NMR and FTIR and the crystal structure of complex 2 was confirmed by X-ray diffraction. Structural analysis revealed that complex 2 crystallizes in the centrosymmetrical P21/c space group with the Ru atom coordinated to two chlorine species in trans form Moreover, the synthesized complexes have been screened for antibacterial activity against Eschericia coli, Bascillus subtilis, Pseudomonas aeruginos, and Staphylococcus aureus, as well as for antifungal activity against Aspergillus niger, Candida albicans, Fusarium oxysporum and Penicillium sp.Figure optionsDownload full-size imageDownload as PowerPoint slide