New boron-nitrogen substituted perylene(bis)diimides

In the past decades, significant progress has been witnessed in azaborine and azaborolide chemistry. These organic/inorganic hybrid compounds were applied as active compounds in OLEDs [1] and in organic field effect... [ view full abstract ]

In the past decades, significant progress has been witnessed in azaborine and azaborolide chemistry. These organic/inorganic hybrid compounds were applied as active compounds in OLEDs ^[1] and in organic field effect transistors (OFET)^[2]. Recently our workgroup presented the implementation of a 1,2-azaborine unit in a styrene-like homopolymer.^[3]

Many substituted 1,2-azaborines are not stable against air and moisture. We stabilize these molecules by using highly stable polycyclic aromatic hydrocarbons and generate molecules with unique optoelectronic properties.

We present a novel symmetric perylene bis(diimide) (PDI) which is annelated to BN-units. The azaborines are further substituted with electron rich heterocycles, which opens up various modification possibilities, and long alkyl chains to improve the solubility.

The bathochromic shift of this PDI compared to the parent molecule, a high molar extinction coefficient and its fluorescence properties, e.g. a small Stokes shift and high quantum yields, make this molecule highly promising for optoelectronic applications. Surprisingly, this molecule shows an exceptionally high thermal stability and is resistant to air, moisture, acidic and basic conditions, which verifies the validity of our attempt to stabilize 1,2-azaborines with large polycyclic aromatic hydrocarbons. The results of the cyclovoltammetry measurements and the quantum chemical calculations underline the potential of this molecule in organic electronic devices. These results were supported by various DFT calculations. Furthermore, the BN-PDI shows a complex solvent-depending optical behaviour in the ground and excited states, which is currently under investigation.

[1] G. Li, Y. Zhao, J. Li, J. Cao, J. Zhu, X. W. Sun, Q. Zhang, J. Org. Chem. 2015, 80, 196-203.

[2] a) X.-Y. Wang, H.-R. Lin, T. Lei, D.-C. Yang, F.-D. Zhuang, J.-Y. Wang, S.-C. Yuan, J. Pei, Angew. Chem. 2013, 125, 3199-3202; b) T. Hatakeyama, S. Hashimoto, S. Seki, M. Nakamura, J. Am. Chem. Soc. 2011, 133, 18614-18617.

[3] B. Thiedemann, P. J. Gliese, J. Hoffmann, P. G. Lawrence, F. D. Sönnichsen, A. Staubitz, Chem. Comm. 2017, Advance Article, DOI: 10.1039/C6CC08599G.