Perylene-bisimide (PBI) metal complexes as stabilizers of carbon nanotubes mixtures for temperature sensing

It has been observed that perylene-bisimide (PBI) derivatives can show interesting properties concerning biosubstrates binding and non-canonical nucleic acids forms stabilization. Moreover, they find use in new materials as stabilizers for carbon nanotubes and temperature sensors. Therefore, it seemed to be of some interest, to perform a study of the metal complexation ability of a newly synthesised ligand, where the central perylene core (chromophore) is connected to two crown-ether residues. Absorbance titrations were analysed, also by means of the HypSpec2014® software, to shed light on the ligand affinity toward Ca2+, Ni2+, Co2+, Fe3+, Pb2+ metal ions and on the stoichiometry of complexes eventually formed. Nickel and cobalt do form the 1:1 complex and not quantitatively. In the case of Ca2+, Fe3+ and Pb2+ the 1:1 ML complex can be quantitatively formed, even if other stoichiometries are possible. The 1:1 Pery-Crown5/Ca, Pery-Crown5/Fe, Pery-Crown5/Pb complexes (together with Pery-Crown5 alone for comparison purposes) were then added to multi-walled carbon nanotubes (MWCNTs) mixtures. The stabilizing ability of the metal complexes towards MWCNTs was quantitatively measured by means of thermal analysis (TGA).The deposition of MWCNT/Pery-Crown5 dispersions on plastic film supporting gold electrodes allowed the fabrication of temperature sensors, whose response was checked. The results obtained are promising and give interesting information on possible modulation and optimisation of the use of metal complexes in MWCNTs-based sensors.