Synthesis of Triazine-Based Materials by Functionalization with Alkynes

Abstract

In this contribution, we report on novel functionalized triazines, which represent new precursors for C/N/(H) compounds or suitable building blocks for carbon-based functional networks. Our results provide insights into the structural properties of molecular carbon nitride materials and their design principles. Tris(1-propynyl)-1,3,5-triazine (C3 N3 (C3 H3 )3 ) and tris(1-butynyl)-1,3,5-triazine (C3 N3 (C4 H5 )3 ) were prepared by substitution reactions of cyanuric chloride (C3 N3 Cl3 ) with prop-1-yne and but-1-yne. The crystal structure of tris(1-propynyl)-1,3,5-triazine was solved in the orthorhombic space group Pbcn (Z=4, a=1500.06 (14), b=991.48(10), c=754.42(6) pm, V=1122.03(18)×10(6) pm(3) ), whereas tris(1-butynyl)-1,3,5-triazine crystallized in the triclinic space group P-1 (Z=6, a=1068.36(12), b=1208.68(12), c=1599.38(16) pm, α=86.67(3), β=86.890(4), γ=86.890(4)°, V=1997.7(4)×10(6) pm(3) ). For both structures, planar triazine units and layerlike packing of the molecules were observed. Tris(1-propynyl)-1,3,5-triazine is built up from hydrogen-bonded zig-zag strands, whereas tris(1-butynyl)-1,3,5-triazine shows parallel layered arrangements. Both compounds were investigated by NMR spectroscopy, IR spectroscopy, and differential thermal analysis/thermogravimetric analysis, which provided insights into their structural, chemical, and thermal properties. In addition, tris(1-propynyl)-1,3,5-triazine was pyrolyzed and a new polymeric triazine-based compound containing mesitylene units was obtained. Its structural features and properties are discussed in detail.