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A series of mono- and bistriazine derivatives were selectively prepared in high yields using microwave irradiation. Donor substituents were attached on the triazine ring, including pyrazolyl-substituted anilines and o-, m-, and p-phenylenediamine as π-conjugated spacers. This method was used to build σ-π-σ-A-σ-D systems for monotriazines and D-σ-A-σ-π-σ-A-σ-D systems for bistriazines. A study of the optoelectronic properties was performed by UV-vis and fluorescence spectroscopy and cyclic voltammetry. The monotriazines do not show any emission, but the bistriazines are blue emitters and show an interesting solvatochromic effect with large Stokes shifts of more than 10,000 cm(-1) in some cases and quantum yields up to 23%. The optoelectronic properties depend on the conjugation and the position and donor character of the substituents and spacers. Cyclic voltammetry was used to determine the energy levels (HOMO and LUMO) in the bistriazines. An increase in the energy of the HOMO and a decrease in the energy of the LUMO were observed upon extending the conjugation. The title compounds showed interesting properties for use in optoelectronic devices, especially as blue emitters.

The synthesis of functionalised carbon nanotubes as receptors for riboflavin (RBF) is reported. Carbon nanotubes, both single-walled and multi-walled, have been functionalised with 1,3,5-triazines and p-tolyl chains by aryl radical addition under microwave irradiation and the derivatives have been fully characterised by using a range of techniques. The interactions between riboflavin and the hybrids were analysed by using fluorescence and UV/Vis spectroscopic techniques. The results show that the attached functional groups minimise the π-π stacking interactions between riboflavin and the nanotube walls. Comparison of p-tolyl groups with the triazine groups shows that the latter have stronger interactions with riboflavin because of the presence of hydrogen bonds. Moreover, the triazine derivatives follow the Stern-Volmer relationship and show a high association constant with riboflavin. In this way, artificial receptors in catalytic processes could be designed through specific control of the interaction between functionalised carbon nanotubes and riboflavin.

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