A new family of π-conjugated oligomers featuring a nonplanar polycyclic aromatic hydrocarbon, corannulene, and a planar aromatic unit, thiophene, is synthesized through an iterative metal-catalyzed coupling protocol. The two structural motifs are connected through an acetylene linkage. In the shorter oligomers, a thiophene unit is attached to one or two corannulenes. In the higher analogues, two, three, and four thiophene units are placed in an alternating fashion with three, four, and five corannulene units, respectively. Photophysical studies reveal extended π-effects that initially increase and then attenuate as a function of the oligomer length. Notably, longer oligomers are found to be highly active for nonlinear absorption and emission properties. The oligomer with three corannulene and two thiophene units exhibits a two-photon absorption cross section of 600 GM and two-photon-excited intense green luminescence. This work, therefore, introduces the concept of combining planar and nonplanar aromatic motifs in the design of π-conjugated discrete oligomers, establishes synthetic feasibility of such hybrid materials, reports on their photophysical properties that is anticipated to have significant implications for future research targets, and features the discovery that corannulene derivatives can exhibit excellent nonlinear optical activity when extended through π-bridges.

New photoluminescent carbon dots with intriguing photoluminescent properties were prepared from carboxylated carbon nanoparticles via covalent bonding of p-phenylenediamine oligomers.

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The highly fluorescent 6,7-dimethoxy-3-trifluoromethylcarbostyril 2 was regioselectively carboxymethylated with bromoacetates 4 at N-1 to give esters of type 5 in good yield. After saponification to 8, succinimidoyl (OSu) esters 9 were prepared. Dyestuffs 9 were reacted in slightly basic aqueous media under mild conditions with free amino acids, esters and peptides to give the fluorescently labeled amino acid derivatives 11 and 13 in good yields. Similarly, aminoglucose