Multifarenes Doped Graphene-like Nanomaterials To Construct Dual-mode Responsive Chemical Sensors

Supramolecular sensors are based on the formation of host and guest compounds by a series of weak interactions between molecules or ions.Therefore,as host,the development of a series of macrocyclic compounds has attracted much attention.Organic macrocycles were usually employed as host in supramolecular chemistry.The most common species,including crown ethers,cyclodextrins,calixarenes,cucurbiturils,and pillararenes,were formed by cyclooligomerization of a single monomeric building block,and exhibited high affinity,substitution patterns,and functionalization.The macrocyclic molecules could be used as receptors in electrochemical and optical sensors with wilder detection range,lower detection limit,and better tolerance of anti-interference.Over the past few decades,nanomaterials have aroused great interests in basic and applied sciences because of their unique physical and chemical characteristics that were substantially different from bulk materials.The introduction of macrocyclic molecules to nanomaterials provided a novel path for the fabrication of hybrid nanomaterials with improved functionalities.Macrocyclic molecules hybrided with nano-materials were versatile and diverse hybrid nanomaterials,which combined and enhanced the characteristics of the two components.In this paper,the novel macrocyclic compound,multifarenes,were used as the supramolecular recognition units,and their composites by hybrization with graphene nanomaterials were prepared for construction of chemical sensors with specific recognition ability.Its main contents are as follows:1.A chemo-sensor constructed by nanohybrid of multifarene[3,3]and r GO for serotonin hydrochloride with dual response in both fluorescence and voltammetry:Fluorescence and electrochemical response of multifarene[3,3](S)to serotonin hydrochloride were discovered,and its composite by hybridization on the surface of reduced graphene oxide was applied for quantitative measurement of serotonin hydrochloride.By using of fluorescence titration,a ratio of 1:1 was confirmed for the host-guest interaction between multifarene[3,3](S)and the serotonin hydrochloride guest with the moderate association constants of(1.7±0.3)×10⁴ M(in DMSO)and(2.7±0.2)×10⁴ M(in water)by non-linear curve fitting,which implied the supramolecular interaction could be irrelevant to the species of solvents.The response of multifarene[3,3](S)to serotonin hydrochloride was improved in both fluorescence and voltammetry,by hybridization of the macrocyclic host with reduced graphene oxide,and the quantitative analysis for the drug was established with a limit of detection low to 3.9×10^-7 M for determination in the real sample of human serum.2.An ultrasensitive sensor with layer-by-layer assembly of chiral multifarene[3,2,1]and g-C₃N₄ quantum dots for enantiorecognition towards thyroxine with dual response in both fluorescence and photoelectrochemical:An ultrasensitive photoelectrochemical(PEC)sensor was developed by hybridization of chiral multifarene[3,2,1](CMF)with graphitic carbon nitride quantum dots(g-C₃N₄ QDs),to realize efficient identification of thyroxine enantiomers.The photocurrent response was produced by g-C₃N₄ QDs and the supramolecular enantiorecognition for thyroxine was achieved by the selective affinity of the macrocyclic compound.The photoelectrochemical electrode was built by sequential assembly of g-C₃N₄ QDs and CMF on the surface of ITO(ITO-g-C₃N₄-CMF QDs).The limits of detection low to 67 p M towards L-T₄and 85p M towards D-T₄in a concentration range from 0.1 n M to 10 n M,was produced by employment of the proposed PEC sensor.The quantitative determination for L/D-T₄in water,human serum and commercial tablet was realized with the proposed PEC sensor to exhibit good stability,reproducibility,repeatability anti-interference ability,and acceptable recoveries.