The synthesis, spectroscopic properties and electrochemistry of (8-quinolinolato)-bis-{1-alkyl-2- (arylazoimidazole)}ruthenium(ii) hexafluorophosphate: single crystal X-ray structure of [ru(q)(meaaime)₂](PF₆)·CH₂Cl₂ [Q = 8-quinolinolate, meaaime = 1-methyl-2-( p-tolylazoimidazole)]

Abstract

The reaction of [Ru(OH₂)₂(RaaiR′)₂]²⁺ [RaaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R–C₆H₄–N=N–C₃H₂–NN(1)–R′, R=H (1), Me (2), Cl (3); R′ = Me (a), Et (b), CH₂Ph (c)] with 8-quinolinol (HQ) in acetone solution followed by the addition of NH₄PF₆ afforded violet, mixed ligand complexes of composition [Ru(Q)(RaaiR′)₂](PF₆). The structure of [Ru(Q)(MeaaiMe)₂](PF₆) (2a) has been confirmed by X-ray diffraction studies. Solution electronic spectra exhibit a strong MLCT band at 560–580 nm in MeCN. Cyclic voltammogrames show a Ru(III)/Ru(II) couple at 1.0–1.1 V versus SCE along with three successive ligand reductions. The electronic properties are correlated with EHMO results.

Keywords:

• Ruthenium(II)
• 1-Alkyl-2-(arylazo)imidazole
• 8-Quinolinol
• X-ray structure
• Electrochemistry

Acknowledgments

Financial assistance from the Council of Scientific and Industrial Research (CSIR), and DSA phase-II, UGC, New Delhi, is gratefully acknowledged. One of us (SJ) is thankful to CSIR for a fellowship. THL and GM thank the National Science Council, ROC, for support.

Supplementary Data

Supplementary data are available from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ. UK [Fax: (internet) +44-1223/336-033; E-mail: [email protected]] on request. The deposition number is 221832. These data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html.