Metal-promoted synthesis, characterization, crystal structure and rna cleavage ability of 2,6-diacetylpyridine bis(2-aminobenzoylhydrazone) lanthanide complexes

Authors:

• Michal Kozłowski,
• Ryszard Kierzek,
• Maciej Kubicki,
• Wanda Radecka-Paryzek

Abstract

New2,6-diacetylpyridine bis(2-aminobenzoylhydrazone) lanthanide complexeswere formed in themetal-induced one-step [1 + 2] condensation reaction between 2,6-diacetylpyridine and 2-aminobenzoylhydrazide in the presence of lanthanide (La³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho ³⁺, Er³⁺, Tm³⁺ or Yb³⁺) nitrates as template agents. The analytical and spectral characterizations of all the compounds were correlated with the single crystal X-ray structural determination of Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺ and Er³⁺ nitrate complexes. The Eu³⁺, Gd³⁺, Tb ³⁺ and Dy³⁺ complexes of pentadentate 2,6-diacetylpyridine bis(2-aminobenzoylhydrazone) with the N₃O₂ set of donor atoms display a high and relatively rare coordination number of 11,whereas the Er³⁺ ion complex is 9-coordinated, which is consistent with the lanthanide contraction phenomenon. The scission of 21-mer RNAwas assessed for Eu³⁺, Gd³⁺ and Tb³⁺ nitrate complexes. Lanthanide complexes not covalently attached to the oligonucleotide are able to cleave RNA at the target site in a sequence-selective or non-selective manner depending on the presence of protecting 12-mer 2′OMe RNA. © 2013 Elsevier Inc.