Acid-Base Properties of the Ground and Excited States of Ruthenium(II) Tris(4′-methyl-2,2′-bipyridine-4-carboxylic Acid)

Chien Hua Su, I. Jy Chang

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The acid dissociation constant, pKa, for the ground and excited states of ruthenium tris(4′-methyl-2,2′-bipyridine-4-carboxylic acid) complex have been measured. The ground state pKa obtained from the pH titration curve of the complex absorption at 454 nm was 2.5. The lifetimes of the excited-state for deprotonated and protonated ruthenium complexes are 595 and 150 ns, respectively. The excited-state pKa* is obtained from the emission titration curve at 630 nm and corrected for the excited-state lifetime to be 4.2. The increase of 1.7 pH units in the acid dissociation constant in the excited-state indicates that the ligand is much more basic in the excited-state. This result confirms the MLCT assignment for the lowest electronic transition of [Ru(mbpyCOOH)3]2+.

Original languageEnglish
Pages (from-to)361-365
Number of pages5
JournalJournal of the Chinese Chemical Society
Volume45
Issue number3
DOIs
Publication statusPublished - 1998 Jan 1

Keywords

  • Acid-base
  • Excited-state
  • Ruthenium(II) tris(4′-methyl-2,2′-bipyndine-4-carboxylic acid)

ASJC Scopus subject areas

  • Chemistry(all)

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