title: Synthesis and structures of a pincer-type rhodium(iii) complex: reactivity toward biomolecules.
abstract: 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 RhIIIcenter. 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.
authors.affiliation: University of Kragujevac, Faculty of Science, Radoje Domanovića 12, 34000 Kragujevac, Serbia. jrosic@kg.ac.rs bugarcic@kg.ac.rs and Lund University, Biochemistry and Structural Biology, KILU, P.O. Box 124, SE-221 00 Lund, Sweden.
authors.forename: Milan M
authors.initials: MM
authors.lastname: Milutinović
authors.affiliation: University of Kragujevac, Faculty of Science, Radoje Domanovića 12, 34000 Kragujevac, Serbia. jrosic@kg.ac.rs bugarcic@kg.ac.rs.
authors.forename: Jovana V
authors.initials: JV
authors.lastname: Bogojeski
authors.affiliation: University of Novi Sad, Faculty of Science, Department of Physics, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia.
authors.forename: Olivera
authors.initials: O
authors.lastname: Klisurić
authors.affiliation: Lehrstuhl für Anorganische und Allgemeine Chemie, Department Chemie und Pharmazie, Universität Erlangen-Nürnberg, Egerlandstr. 1, 91058 Erlangen, Germany.
authors.forename: Andreas
authors.identifier: http://orcid.org/0000-0002-2858-9406
authors.initials: A
authors.lastname: Scheurer
authors.affiliation: Lund University, Biochemistry and Structural Biology, KILU, P.O. Box 124, SE-221 00 Lund, Sweden.
authors.forename: Sofi K C
authors.initials: SK
authors.lastname: Elmroth
authors.affiliation: University of Kragujevac, Faculty of Science, Radoje Domanovića 12, 34000 Kragujevac, Serbia. jrosic@kg.ac.rs bugarcic@kg.ac.rs.
authors.forename: Živadin D
authors.initials: ŽD
authors.lastname: Bugarčić
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry; D005978:Glutathione / Q000737:chemistry; D006157:Guanosine Monophosphate / Q000737:chemistry; D006639:Histidine / Q000737:chemistry; D007700:Kinetics; D008024:Ligands; D008715:Methionine / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D011485:Protein Binding; D012238:Rhodium / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry
chemical_list: D002614:Chelating Agents; D056831:Coordination Complexes; D008024:Ligands; D012710:Serum Albumin, Bovine; D006639:Histidine; D006157:Guanosine Monophosphate; D004247:DNA; D008715:Methionine; D012238:Rhodium; D005978:Glutathione