Synthesis and structures of a pincer-type rhodium(III) complex: Reactivity toward biomolecules

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A novel rhodium(iii) complex [RhIII(H2LtBu)Cl3] (1) (H2LtBu = 2,6-bis(5-tert-butyl-1H-pyrazol-3-yl)pyridine) containing a pincer type, tridentate nitrogen-donor chelate system was synthesized. Single crystal X-ray structure analysis revealed that 1 crystallizes in the orthorhombic space group Pbcn with a = 20.7982(6), b = 10.8952(4), c = 10.9832(4) Å, V = 2488.80(15) Å3, and eight molecules in the unit cell. The rhodium center in the complex [RhIII(H2LtBu)Cl3] (1) is coordinated in a slightly distorted octahedral geometry by the tridentate N,N,N-donor and three chloro ligands, adopting a mer arrangement with an essentially planar ligand skeleton. Due to the tridentate coordination of the N,N,N-donor, the central nitrogen atom N1 is located closer to the RhIII center. The reactivity of the synthesized complex toward small biomolecules (l-methionine (l-Met), guanosine-5′-monophosphate (5′-GMP), l-histidine (l-His) and glutathione (GSH)) and to a series of duplex DNAs and RNA was investigated. The order of reactivity of the studied small biomolecules is: 5′-GMP > GSH > l-Met > l-His. Duplex RNA reacts faster with the [RhIII(H2LtBu)Cl3] complex than duplex DNA, while shorter duplex DNA (15mer GG) reacts faster compared with 22mer GG duplex DNA. In addition, a higher reactivity is achieved with a DNA duplex with a centrally located GG-sequence than with a 22GTG duplex DNA, in which the GG-sequence is separated by a T base. Furthermore, the interaction of this metal complex 1 with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) was examined by absorption (UV-Vis) and emission spectral studies (EthBr displacement studies). Overall, the studied complex exhibited good DNA and BSA interaction ability.


  • Milan M. Milutinović
  • Jovana V. Bogojeski
  • Olivera Klisurić
  • Andreas Scheurer
  • Sofi K C Elmroth
  • Živadin D. Bugarčić
External organisations
  • Friedrich-Alexander University Erlangen-Nürnberg
  • University of Kragujevac
  • Lund University
  • University of Novi Sad
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Inorganic Chemistry
Original languageEnglish
Pages (from-to)15481-15491
Number of pages11
JournalDalton Transactions
Issue number39
Publication statusPublished - 2016
Publication categoryResearch