Construction Of New Sensor Arraysbased On Dimeric Porphyrins And Study Of Their Sensing Detections

The unique structures as well assuperior photophysical and photochemicalproperties of dimeric porphyrins make them an extremely versatile class of compoundsfor a variety of applications in photoelectric conversion material, catalyisis, host-guestinteractionand molecular recognition. Compared with porphyrin monomers, owing tolarger binding constant towards analytes resulting from the synergy between theindividual porphyrin constituents, selective binding a variety of substrates by theformed molecular cleftsas well as differences in coordination ability of porphyrindimers rising from the various metal centres, porphyrin dimers have been the focus ofconsiderable attention in molecular recognition field, which could combine coordination,hydrogen bond and π-π stacking interaction to respond to analytes intensively. Bystimulating mammalian olfactory/gustatory sense, visualized sensor arrays utilizevarious specific and sensitive material as sensitive units and prove to be a simple, fast,and low-cost method. In this study, five series dimeric porphyrins with differentmoleclular flexibilities as well as different lengthand structures of bridge groups andtheir transition metal complexes were synthesized and characterized; systematicallyresearch was carried out on spectral detection effect of dimeric porphyrins towardscarbamate pesticides and mechanism of interaction; a novel colorimetric sensor array aswell as a novel fluorescent liquid array were fabricated for the identification andquantitative analysis of carbamate pesticides with various concentrations; thecolorimetric sensor array based on designed dimeric metalloporphyrins was developedas a new approach for the detection of carbamate pesticides in cucumber or grapesample;based on designed dimeric porphyrins, indicators and metal salts, a colorimetricsensor array forqualitatively and quantitatively detection gas markers of lung cancerwas constructed.Researches were summarized as follows:(1) Five series of porphyrin dimers and their transition metal complexes that werecovalently linked by anhydride bond(P1), amido bond(P2, P3) and ester bond(P4, P5)were firstly synthesized, starting from their corresponding monomers and bridgemolecules. Then the structures of the30porphyrin dimers were characterized by waysof1H NMR, IR, UV-Vis and elemental analysis.(2)Four widely-used carbamate pesticides including aldicarb, methomyl,indoxacarb and carbendazim were detected with25as-prepared dimeric metalloporphyrins by UV-Visible and fluorescence spectrophotometry. According tospectral detection results, ZnP1，MnP1，CoP2，NiP2，CuP3，NiP3，MnP4，CoP4，ZnP5and CuP5were selected as sensing materials for aldicarb. CuP3，ZnP3，CoP4，NiP4，ZnP5，MnP5，CuP1，MnP1，ZnP2，CuP2and NiP2were suitable for the detectionof indoxacarb. Meanwhile, CoP1，NiP1，MnP2，CoP3，ZnP3，MnP4，CuP4，ZnP5and NiP5were selected as sensing materials for methomyl. While CoP1，NiP1，ZnP2，CoP2，MnP3，CuP3，CuP4，MnP4，CoP4，CoP5and ZnP5were suitable for thedetection of carbendazim. The molecular interaction of ZnP2and aldicarb has beeninvestigatedby UV–vis and fluorescence spectroscopies.The association constant,interaction stoichiometry and thermodynamic constants of the bindings were obtainedthrough Benesi–Hildebrand (B–H) method. The one-step1:2interaction took place inthe ZnP2-aldicarb system. The association constants decreased with temperatureincreasement and interaction between ZnP2and aldicarb was a entropy increasedexothermic reaction.(3) The interaction between dimeric metalloporphyrins and aldicarb, methomyl,indoxacarb as well as carbendazim was analyzed by molecular docking. Total-score andCrash were used to describe results. Complex conformation showed that the interactionbetween dimeric metalloporphyrins and indoxacarb, carbendazim was via coordinationbond, hydrogen bond and π-π stacking effect. While the interaction between dimericmetalloporphyrins and aldicarb, methomyl was via oordination bondand hydrogen bond.The electronic structure of metal ion as well as the structure of bridge group bothaffected the interaction between dimeric metalloporphyrins and carbamate pesticides.(4) Based on the selected responsive porphyrins, a5×5colorimetric sensor array wasfabricated for the identification and quantitative analysis of carbamate pesticides overvarious concentrations.A fluorescent liquid array composing of five zinc porphyrindimerswas also developed and applied for the quantitative analysis of aldicarb,methomyl, indoxacarb and carbendazim. RGB data from the sensor array was analyzedwith pattern recognition methods, including principlecomponentanalysis(PCA),hierarchicalclusteranalysis(HCA) and linear discriminantanalysis(LDA). The results demonstrated the potential of both the two sensor arrays infacial identification and quantitative analysis of carbamate pesticides, and theconstructed sensor arrays proved to be simple, fast, accurate and stable. By combiningthe two sensor arrays into an integrated one, more accurate results could be obtained.(5)The colorimetric sensor array based on dimeric metalloporphyrins was developed as a new approach for the detection of carbamate pesticides in cucumber or grapesample. The detection time of the method was as low as3min. The linearity of themethod was in the range from0.5to5ppm with the correlation coefficients rangingfrom0.9916to0.9983. The limits of detection of the method were14~33ppb. Therepeatability of the method expressed as the relative standard deviations by five parallelexperiments at the concentration levels of2.5ppm and4ppm each of the carbamatepesticides in grape or cucumber samples varied from3.4%to6.5%. The developedmethod has been successfully applied for the analysis of aldicarb, methomyl,carbendazim and indoxacarb in grape and cucumber samples. The recoveries of themethod for the target carbamate pesticides from the real samples at spiking levels of2.5and4ppm were in the range between76.4~88.1%(n=5). Compared with traditionaltechniques, the proposed colorimetric method is convenient, environment-friendly,sensitive, fast and low-cost, which provides a valuable reference for the real-timeon-line detection of carbamate pesticides.(6)The responses of dimeric porphyrins for butanal, acetone, hexaldehyde,heptaldehyde, benzene, para-xylene, styrene, cyclohexane, decane and undecane wereinvestigated with UV-Vis absorption spectroscopy. A sensor array was constructed withthe aid of sol-gel technique, employing responsive dimeric porphyrins, dyes with largepermenant dipoles and metal salts as sensing elements.10gas markes with differentconcentrations were identified by the developed colorimetric sensor array. The RGBvalues of the colorimetric sensor array were analyzed by pattern recognition method,including cluster analysis (HCA), and principal component analysis (PCA). The resultssuggest that the developed sensor array system is an excellent sensing platform for theidentification and quantitative analysis of gas markers, which provides a new idea forthe detection and screening of lung cancer.