Synthesis, characterization, and luminescence properties of salophen-bridged heterotrinuclear Ru–M–Ru (M = Ni, Zn) hybrid complexes composed of coordination and organometallic sites

Abstract

Six heterotrinuclear complexes, Ni[C₅H₂NBr{N = COC₆H₃C≡C(trans-Ru(dppe)₂)C≡CC₆H₄R}₂ (1a–c) and Zn[C₅H₂NBr{N = COC₆H₃C≡C(trans-Ru(dppe)₂)C≡CC₆H₄R}₂] (2a–c), have been prepared by reaction of [(OH)(COH)C₆H₃C≡C(trans-Ru(dppe)₂)C≡CC₆H₄R] (dppe = 1,2-bis(diphenylphosphino)ethane; R = H, NO₂, OCH₃) with nickel acetate or zinc acetate, followed by addition of 2,3-diamino-5-bromopyridine. Our synthetic efforts are discussed along with spectroscopic and electronic characterization of the compounds. The complexes were studied by thermal and electrochemical analyses. They are thermally robust and show quasireversible redox events attributed to Ru(II)/Ru(III) and Ni (II)/Ni(III) couples for 1a–c and Ru(II)/Ru(III) couples for 2a–c. All complexes are luminescent, emitting in the blue-green region at room temperature. Their emission is influenced by substituents and the π-acidic character of the coordinated groups. Second harmonic generation efficiencies of the complexes were measured by the Kurtz powder technique, indicating that all complexes are promising for applications as nonlinear optical materials.

KEYWORDS:

• Hybrid complexes
• luminescence
• electrochemistry
• nonlinear optics

Disclosure statement

No potential conflict of interest was reported by the authors.