Synthesis of 3,3′-dihydroxy-2,2′-diindan-1,1′-dione derivatives for tautomeric organic semiconductors exhibiting intramolecular double proton transfer

To investigate potential applications of the 3,3 '-dihydroxy-2,2 '-biindan-1,1 '-dione (BIT) structure as an organic semiconductor with intramolecular hydrogen bonds, a new synthetic route under mild conditions is developed based on the addition reaction of 1,3-dione to ninhydrin and the subsequent hydrogenation of the hydroxyl group. This route affords several new BIT derivatives, including asymmetrically substituted structures that are difficult to access by conventional high-temperature synthesis. The BIT derivatives exhibit rapid tautomerization by intramolecular double proton transfer in solution. The tautomerizations are also observed in the solid state by variable temperature measurements of X-ray diffractometry and magic angle spinning C-13 solid-state NMR. Possible interplay between the double proton transfer and the charge transport is suggested by quantum chemical calculations. The monoalkylated BIT derivative with a lamellar packing structure suitable for lateral charge transport in films shows a hole mobility of up to 0.012 cm(2) Vy(1) sy(1) with a weak temperature dependence in an organic field effect transistor.

Automated summary

This study develops a new synthetic route to synthesize several new BIT derivatives. The properties of these derivatives are investigated experimentally and computationally, revealing rapid tautomerization in solution and solid state. It is also found that one of the derivatives exhibits good charge transport performance in an organic field effect transistor.