Diarylethene-containing cyclometalated platinum(II) complexes: Tunable photochromism via metal coordination and rational ligand design

Jacky Chi Hung Chan, Wai Han Lam, Hok Lai Wong, Nianyong Zhu, Wing Tak Wong, Vivian Wing Wah Yam

Research output: Journal article publicationJournal articleAcademic researchpeer-review

168 Citations (Scopus)

Abstract

The synthesis, characterization, electrochemistry, photophysics and photochromic behavior of a new class of cyclometalated platinum(II) complexes [Pt(C∧N)(O∧O)] (1a-5a and 1b-5b), where C ∧N is a cyclometalating 2-(2′-thienyl)pyridyl (thpy) or 2-(2′-thienothienyl)pyridyl (tthpy) ligand containing the photochromic dithienylethene (DTE) unit and O∧O is a β-diketonato ligand of acetylacetonato (acac) or hexafluoroacetylacetonato (hfac), have been reported. The X-ray crystal structures of five of the complexes have also been determined. The electrochemical studies reveal that the first quasi-reversible reduction couple, and hence the nature of lowest unoccupied molecular orbital (LUMO) of the complexes, is sensitive to the nature of the ancillary O ∧O ligands. Upon photoexcitation, complexes 1a-3a and 1b-3b exhibit drastic color changes, ascribed to the reversible photochromic behavior, which is found to be sensitive to the substituents on the pyridyl ring and the extent of π-conjugation of the C∧N ligand as well as the nature of the ancillary ligand. The thermal bleaching kinetics of complex 1a has been studied in toluene at various temperatures, and the activation barrier for the thermal cycloreversion of the complex has been determined. Density functional theory (DFT) calculations have been performed to provide an insight into the electrochemical, photophysical and photochromic properties.
Original languageEnglish
Pages (from-to)12690-12705
Number of pages16
JournalJournal of the American Chemical Society
Volume133
Issue number32
DOIs
Publication statusPublished - 17 Aug 2011
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry

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