Structure and reactivity of [Ru-II(terpy)(NN)Cl]Cl complexes: consequences for biological applications

Journal article

Publication Details

Author(s): Chrzanowska M, Katafias A, Impert O, Kozakiewicz A, Surdykowski A, Brzozowsk P, Franke A, Zahl A, Puchta R, van Eldik R
Journal: Dalton Transactions
Publication year: 2017
Volume: 46
Journal issue: 31
Pages range: 10264-10280
ISSN: 1477-9226
eISSN: 1477-9234


The crystal structures of [Ru-II(terpy)(bipy)Cl]Cl center dot 2H(2)O and [Ru-II(terpy)(en) Cl]Cl center dot 3H(2)O, where terpy = 2,2':6',2 ''-terpyridine, bipy = 2,2'-bipyridine and en = ethylenediamine, were determined and compared to the structure of the complexes in solution obtained by multi-nuclear NMR spectroscopy in DMSOd-6 as a solvent. In aqueous solution, both chlorido complexes aquate fully to the corresponding aqua complexes, viz. [Ru-II(terpy)(bipy)(H2O)](2+) and [Ru-II(terpy)(en)(H2O)](2+), within ca. 2 h and ca. 2 min at 37 degrees C, respectively. The spontaneous aquation reactions can only be suppressed by chloride concentrations as high as 2 to 4 M, i.e. concentrations much higher than that found in human blood. The corresponding aqua complexes are characterized by pK(a) values of ca. 10 and 11, respectively, which suggest a more labile coordinated water molecule in the case of the [Ru-II(terpy)(en)(H2O)](2+) complex. Substitution reactions of the aqua complexes with chloride, cyanide and thiourea show that the [Ru-II(terpy)(en)(H2O)](2+) complex is 30-60 times more labile than the [Ru-II(terpy)(bipy)(H2O)](2+) complex at 25 degrees C. Water exchange reactions for both complexes were studied by O-17-NMR and DFT calculations (B3LYP(CPCM)/def2tzvp//B3LYP/def2svp and omega B97XD(CPCM)/def2tzvp//B3LYP/def2svp). Thermal and pressure activation parameters for the water exchange and ligand substitution reactions support the operation of an associative interchange (I-a) process. The difference in reactivity between these complexes can be accounted for in terms of pi-back bonding effects of the terpy and bipy ligands and steric hindrance on the bipy complex. Consequences for eventual biological application of the chlorido complexes are discussed.

FAU Authors / FAU Editors

Franke, Alicja Dr.
Lehrstuhl für Bioanorganische Chemie
Puchta, Ralph PD Dr.
Lehrstuhl für Anorganische und Metallorganische Chemie
van Eldik, Rudi Prof. Dr.
Naturwissenschaftliche Fakultät
Zahl, Achim Dr.
Lehrstuhl für Bioanorganische Chemie

How to cite

Chrzanowska, M., Katafias, A., Impert, O., Kozakiewicz, A., Surdykowski, A., Brzozowsk, P.,... van Eldik, R. (2017). Structure and reactivity of [Ru-II(terpy)(NN)Cl]Cl complexes: consequences for biological applications. Dalton Transactions, 46(31), 10264-10280.

Chrzanowska, Marta, et al. "Structure and reactivity of [Ru-II(terpy)(NN)Cl]Cl complexes: consequences for biological applications." Dalton Transactions 46.31 (2017): 10264-10280.


Last updated on 2018-31-10 at 12:10