Cobalt(ii)-8-hydroxyquinoline-5-sulfonic acid complex/N-(4-aminobutyl)-N-ethylisoluminol/reduced graphene hybrids as nanocatalytic reaction platforms for chemiluminescence

Abstract

In this work, we report a novel GO-based hybrid consisting of N-(4-aminobutyl)-N-ethylisoluminol (ABEI), a cobalt(II)-8-hydroxyquinoline-5-sulfonic acid complex (Co^II(HQS)₂) and reduced GO hybrids (Co^II(HQS)₂/ABEI/rGO) with good stability and easy purification via a facile strategy by virtue of π–π stacking and coordination, which could be used as an excellent nanocatalytic reaction platform for chemiluminescence (CL) when reacted with hydrogen peroxide, dissolved oxygen and periodate in alkaline solution. This was attributed to the fact that Co^II(HQS)₂ catalyzed the generation of reactive radicals such as HO˙, O₂˙⁻, and periodate anion radicals (I^VI) and π-conjugated carbon radicals (π–CC˙) as well as ABEI˙⁻ on the GO surface. GO as a reaction platform facilitated the reaction of ABEI˙⁻ with O₂˙⁻ to produce intensive CL. It was also found that there was a dilution-initiated CL enhancement in Co^II(HQS)₂/ABEI/rGO–H₂O₂ system but not in the Co^II(HQS)₂/ABEI/rGO–O₂ and Co^II(HQS)₂/ABEI/rGO–KIO₄ systems. This was due to the competition of the dilution-decreased reduced GO quenching effect and dilution-decreased Co^II(HQS)₂ concentration. This work provides new insight into the physicochemical properties of functionalized GO hybrids and excellent nanocatalytic platforms for CL reactions, which may find future applications in bioassays, biosensors, bioimaging and microchips.