Solution processible Co(III) quinoline-thiosemicarbazone complexes: synthesis, structure extension, and Langmuir-Blodgett deposition studies

Seven readily synthesized 8-quinoline-4-R-3-thiosemicarbazone ligands [where R = phenyl (L1H), 4-fluorophenyl (L2H), 4-iodophenyl (L3H), 4-nitrophenyl (L4H), 4-carboxyphenyl (L5H), 3-picolyl (L6H), and octadecyl (L7H)], and their corresponding Co(III) coordination complexes, [Co(L)2]BF4, have been synthesized and characterized. Crystallographic analysis of the complexes revealed that the substituents significantly alter solid-state supramolecular network topologies. The solution processability of these complexes was confirmed by incorporating a long carbon alkyl-chain into the ligand (L7H) and immobilizing the complex onto quartz slides using Langmuir-Blodgett deposition. The facile and modular synthesis of these thiosemicarbazone-based ligands coupled with the potential to exploit multiple applications makes these compounds excellent candidates for functional supramolecular materials