Synthesis, characterization and photophysical properties of PPh2-C-2-(C6H4)(n)-C-2-PPh2 based bimetallic Au(I) complexes

Igor O. Koshevoy*, Chia-Li Lin, Cheng-Chih Hsieh, Antti J. Karttunen, Matti Haukka, Tapani A. Pakkanen, Pi-Tai Chou

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

A family of the diphosphines PPh2C2(C6H4)(n)C2PPh2 (n = 0-3), which possess a dialkynyl-arene spacer between the phosphorus atoms, was used for the synthesis of a series of bimetallic gold(I) complexes 1-7. Unlike the corresponding polynuclear Au(I) clusters, which show unique phosphorescence, 1-7 reveal dual emissions consisting of fluorescence and phosphorescence. The results are rationalized, in a semi-quantitative manner, by the trace (1-3) to zero (4-7) contribution of MLCT varying with the number of conjugated phenylene rings. As a result, unlike typical polynuclear Au(I) clusters with 100% triplet state population, the rate constant of the S-1 -> T-1 intersystem crossing is drastically reduced to 10(9) s(-1) (4-7)-10(10) s(-1) (1-3), so that the fluorescence radiative decay rate can compete or even dominates. The drastic O-2 quenching of phosphorescence demonstrates the unprotected nature of the emission chromophores in 1-7, as opposed to the well protected, O-2 independent phosphorescence in most multimetallic Au(I) clusters.

Original languageEnglish
Pages (from-to)937-945
Number of pages9
JournalDalton Transactions
Volume41
Issue number3
DOIs
Publication statusPublished - 2012
MoE publication typeA1 Journal article-refereed

Keywords

  • INTRAMOLECULAR PROTON-TRANSFER
  • GOLD(I) ACETYLIDE COMPLEXES
  • BRIDGING PHOSPHINE-LIGANDS
  • THE-IDENTITY APPROXIMATION
  • METAL ALKYNYL COMPLEXES
  • LIGHT-EMITTING-DIODES
  • ZETA VALENCE QUALITY
  • AUXILIARY BASIS-SETS
  • CRYSTAL-STRUCTURE
  • EXCITED-STATE

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