The straightforward synthesis of N-coordinated ruthenium 4-aryl-1,2,3-triazolato complexes by [3 + 2] cycloaddition reactions of a ruthenium azido complex with terminal phenylacetylenes and non-covalent aromatic interactions in structures

Abstract

The straightforward preparation of N-coordinated ruthenium triazolato complexes by [3 + 2] cycloaddition reactions of a ruthenium azido complex [Ru]–N₃ (1, [Ru] = (η⁵-C₅H₅)(dppe)Ru, dppe = Ph₂PCH₂CH₂PPh₂) with a series of terminal phenylacetylenes is reported. The reaction products, N(2)-bound ruthenium 4-aryl-1,2,3-triazolato complexes such as [Ru]N₃C₂H(4-C₆H₄CN) (2), [Ru]N₃C₂H(4-C₆H₄CHO) (3), [Ru]N₃C₂H(4-C₆H₄F) (4), [Ru]N₃C₂H(Ph) (5) and [Ru]N₃C₂H(4-C₆H₄CH₃) (6) were produced from 4-ethynylbenzonitrile, 4-ethynylbenzaldehyde, 1-ethynyl-4-fluorobenzene, phenylacetylene and 4-ethynyltoluene, respectively, at 80 °C or above under an atmosphere of air. To the best of our knowledge, this is the first example of the preparation of N-coordinated ruthenium aryl-substituted 1,2,3-triazolato complexes by the [3 + 2] cycloaddition of a metal-coordinated azido ligand and a terminal aryl acetylene, less electron-deficient terminal aryl alkynes. All of the compounds have been fully characterized and the structures of complexes 2, 3, 5 and 6 were confirmed by single-crystal X-ray diffraction analysis. Each compound participates in non-covalent aromatic interactions in the solid-state structure which can be favorable in the binding of DNA/biomolecular targets and has shown great potential in the development of biologically active anticancer drugs.