A new synthetic route to prepare a series of versatile 2,7-substituted pyrene synthons for the synthesis of pyrene-fused azaacenes is described. By using such synthons, a library of eight pyrene-fused azacenes with different electronic structures and in most cases with enhanced solubility has been synthesized and characterized.

We investigated the synthesis of one-dimensional nanostructures via Schiff base (imine) formation on three close-packed coinage metal (Au, Ag, and Cu) surfaces under ultrahigh vacuum conditions. We demonstrate the feasibility of forming pyrene-fused pyrazaacene-based oligomers on the Ag(111) surface by thermal annealing of tetraketone and tetraamine molecules, which were designed to afford cyclocondensation products. Direct visualization by scanning tunneling microscopy of reactants, intermediates, and products with submolecular resolution and the analysis of their statistical distribution in dependence of stoichiometry and annealing temperature together with the inspection of complementary X-ray photoelectron spectroscopy signatures provide unique insight in the reaction mechanism, its limitations, and the role of the supporting substrate. In contrast to the reaction on Ag(111), the reactants desorb from the Au(111) surface before reacting, whereas they decompose on the Cu(111) surface during the relevant thermal treatment.

An approach for introducing twists in pyrene-fused azaacenes is reported. Depending on the volume and the rigidity of the silyl groups, different-sized twist angles, which oscillate between 4° and 24°, are induced along the longitudinal conjugated backbone.

The synthesis and characterisation of a soluble pyrene-fused tetraazaoctacene derivative has been achieved by developing a key pyrene-based building block with four solubilising groups.

A series of pyrene-fused azaacenes with four and six linearly fused rings that possess LUMO levels between -3.7 and -4.3 eV is reported. These LUMO values are remarkably lower than those typically observed for pyrene-fused azaacenes, even for systems with sixteen linearly fused rings, and are comparable to those observed for state-of-the-art n-azaacenes.

Various azo compounds (Modified dyes) have been synthesised by chemical modification of areca nut extract (epicatechin), a plant-based Polyphenolic compound to get semi-synthetic dyes. Three different primary amines namely p- nitro aniline, p-anisidine and aniline, were diazotized to form their corresponding diazonium salts which were further coupled with an areca nut extract. Preliminary characterization of the areca nut extract and the resultant azo compounds (Modified dyes) was carried out in terms of melting point, solubility tests, thin layer chromatography, UV–Visible and FTIR spectroscopy. These modified dyes were further applied on polyester and nylon fabrics and % dye exhaustion was evaluated. Dyed fabrics were further tested for their fastness properties such as wash fastness, rubbing fastness, light fastness and sublimation fastness. The results of the fastness tests indicate that, all the three modified dyes have good dyeability for polyester and nylon fabrics. The dyed fabrics were also tested for ultraviolet protection factor which showed very good ultraviolet protection.

The synthesis and properties of 11,11,12,12-tetracyano-4,5-pyrenoquinodimethanes (4,5-TCNPs), a new family of isolable and air-stable o-quinodimethanes, are reported. The ortho disposition of the dicyanomethane substituents strongly polarizes the pyrene framework to promote broad and intense intramolecular charge-transfer transitions. In addition, spectroscopic studies reveal that 4,5-TCNPs violate Kasha's rule and emit from the S2 level.

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