Nanoscale molecular rods with a new building block for solubility enhancement

A new building block bearing a [1,3]dioxolo[4,5-f][1,3]benzodioxole core was developed to enhance the solubility of molecular rods by lateral alkyl chains. On incorporation in molecular rods with oligospiroketal structure, the straight geometry is retained, which was concluded from the X-ray crystal structure analysis of one of the rods. The determination of the solubility of a collection of rods bearing this building block revealed that already a butyl group efficiently hinders the aggregation of the rods and consequently causes a considerable enhancement of the solubility. Piperidine rings are located at the ends of the rods, which offer the opportunity for versatile functionalization. Thus, an N,N'-bis(azidoacetyl)-functionalized rod was prepared, which could serve as rigid linkage, initiated by a Click reaction.