The open molecular framework of paramagnetic lithium octabutoxy-naphthalocyanine: Implications for the detection of oxygen and nitric oxide using EPR spectroscopy

Ramasamy P. Pandian, Young Il Kim, Patrick M. Woodward, Jay L. Zweier, Periakaruppan T. Manoharan, Periannan Kuppusamy

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

The oxygen-induced broadening of the electron paramagnetic resonance (EPR) spectrum of lithium octa-n-butoxy-naphthalocyanine (LiNc-BuO) is interpreted in terms of its open molecular framework crystal structure. LiNc-BuO was prepared as a microcrystalline powder and its structure analyzed using X-ray powder diffraction techniques. The structure contains strongly coupled dimers of LiNc-BuO molecules, which favors a high degree of spin exchange, and results in a single sharp EPR line. The molecular packing leads to a structure with open channels large enough (10 × 6 Å2) for the penetration of small diatomic paramagnetic molecules such as oxygen (O2) and nitric oxide (NO), as well as the larger triatomic species, nitrogen dioxide (NO 2). The EPR linewidth of LiNc-BuO is extremely sensitive to the concentration of paramagnetic gases in the pressure range of 0-760 mmHg. The effect of oxygen on LiNc-BuO is reversible without any signs of permanent adsorption or chemical oxidation. The time response of the effect of oxygen is extremely rapid (0.24 s). The paramagnetic gas-sensing properties of LiNc-BuO are attributed to the open molecular framework of the crystal structure. The oxygen-sensing property, combined with the previously established biostability and biocompatibility of this material, should enable precise and accurate measurements of oxygen concentration in biological systems using EPR spectroscopy.

Original languageEnglish (US)
Pages (from-to)3609-3618
Number of pages10
JournalJournal of Materials Chemistry
Volume16
Issue number36
DOIs
StatePublished - 2006
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Materials Science(all)

Fingerprint

Dive into the research topics of 'The open molecular framework of paramagnetic lithium octabutoxy-naphthalocyanine: Implications for the detection of oxygen and nitric oxide using EPR spectroscopy'. Together they form a unique fingerprint.

Cite this