Abstract: 2,2′-Bis-indan-1,1′,3,3′-tetrone(1), 5,5′-dimethyl-2,2′-bis-indan-1,1′,3,3′-tetrone(2) and 4,4′,5,5′,6,6′,7,7′-octachloro-2,2′-bis-indan-1,1′,3,3′-tetrone(3) were prepared using phthalic anhydride, 4-methylphthalic anhydride and tetrachlorophthalic anhydride as raw materials by the Gabriel & Leupold method. The characteristic of compound 1—3 were confirmed by elemental analysis, ¹H NMR, FTIR and MS. The ESR parameters were given by ESR analysis. As a new discovery, compound 1—3 showed excellent ESR spectra. These compounds, which are pure organic magnetic molecules containing only C, H, O and Cl, can all form stable free radicals. Through quantum-chemistry calculation, while the position that the free radicals occupy and the most possible existing form of these compounds were brought forward. That was as en-ol form and had one hydrogen bond in the molecule.

Key words: Bis-(1,3-indanedione), Isomerization, Hydrogen bond, ESR spectrometry, Quantum-chemistry calculation