Spectroscopic studies and structures of trans-ruthenium(II) and ruthenium(III) bis(cyanide) complexes supported by a tetradentate macrocyclic tertiary amine ligand

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Fu-Wa Lee
  • Chi-Ming Che
  • Fong Cheng Yung
  • David Lee Phillips
  • Nianyong Zhu

Detail(s)

Original languageEnglish
Pages (from-to)10308-10316
Journal / PublicationInorganic Chemistry
Volume47
Issue number22
Publication statusPublished - 17 Nov 2008

Abstract

trans-[Ru(16-TMC)(C≡N)2] (1; 16-TMC = 1,5,9,13- tetramethyl-1,5,9,13-tetraazacyclohexadecane) was prepared by the reaction of trans-[Ru(16-TMC)Cl2]Cl with KCN in the presence of zinc powder. The oxidation of 1 with bromine gave trans-[Ru(16-TMC)(C≡N)2] + isolated as PF6 salt (2·PF6). The Ru-C/C-N distances are 2.061(4)/1.130(5) and 2.069(5)/1.140(7) Å for 1 and 2, respectively. Both complexes show a Ru(III/II) couple at 0.10 V versus FeCp2 +/0. The UV-vis absorption spectrum of 1 is dominated by an intense high-energy absorption at λmax = 230 nm, which is mainly originated from dπ(RuII) → π*(N≡C-Ru-C≡N) charge-transfer transition. Complex 2 shows intense absorption bands at λmax ≤ 228 nm and weaker vibronically structured absorption bands with peak maxima at 315-441 nm (εmax ≈ (5-8) × 102 dm3 mol -1 cm-1), which are assigned to dπ(RuIII) → π*(N≡C-Ru-C≡N) and σ(-C≡N) → d(RuIII) charge-transfer transition, respectively. Density functional theory and time-dependent density-functional theory calculations have been performed on trans-[(NH3)4Ru(C≡N)2] (1′) and trans-[(NH3)4Ru(C≡N) 2]+ (2′) to examine the Ru-cyanide interaction and the nature of associated electronic transition(s). The 230 nm band of 1 has been probed by resonance Raman spectroscopy. Simulations of the absorption band and the resonance Raman intensities show that the nominal νC≡N stretch mode accounts for ca. 66% of the total vibrational reorganization energy. A change of nominal bond order for the cyanide ligand from 3 to 2.5 is estimated upon the electronic excitation. © 2008 American Chemical Society.

Citation Format(s)

Spectroscopic studies and structures of trans-ruthenium(II) and ruthenium(III) bis(cyanide) complexes supported by a tetradentate macrocyclic tertiary amine ligand. / Wong, Chun-Yuen; Lee, Fu-Wa; Che, Chi-Ming; Yung, Fong Cheng; Phillips, David Lee; Zhu, Nianyong.

In: Inorganic Chemistry, Vol. 47, No. 22, 17.11.2008, p. 10308-10316.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review