Synthesis Of2-aryl-1H-imidazo[4,5-b]phenazine Derivatives And Study On Their Ion Recognition

Ion recongniton plays an important role in the host-guest chemistry. It has beendemonstrated that the arrival of any new chemosensors can accelerate thedevelopment of supramolecular chemistry and provide new opportunities for thesensor material science. Now days, thanks to the enthusiastic efforts of scientists,many good chemosensors were reported, and some design rules have beensummarized. However, due to fluorescence quenching, the dependence on organicsolvents or, more specifically, the interference from other anions, there are still majorchallenges to be overcome in developing highly selective chemosensors. Phenazinederivatives have been synthesized and been used for organic electronics for a longtime, but they have seldom been used in host-guest chemistry. Phenazines are idealplatforms for the development of cation, anion, and neutral molecule recognition.Moreover, among the different fluorogenic units, phenazine is very sensitive toconformational change. In this dissertation, we focus on the preparation of phenazinesand1H-imidazo[4,5-b]phenazine derivatives, and investigation of their ionrecognition properties.In the first part, a non-sulfur, recyclable sensor of mercury ions has been designedand synthesized. The sensor was bearing1H-Imidazo[4,5-b]Phenazine derivatives,which shown brilliant fluorescent response for Hg2+ions in aqueous solution. Thedetection limit of the sensor towards Hg2+is1.6×10-7M, and other ions, includingFe3+, Ca2+, Cu2+, Co2+, Ni2+, Cd2+, Pb2+, Zn2+, Cr3+, and Mg2+had nearly no influenceon the probing behavior. Notably, this sensor serves as a recyclable component insensing materials. In addition, test strips based on the sensor were fabricated, whichalso exhibits a good selectivity to Hg2+as in solution. We believe the test strips couldact as a convenient and efficient Hg2+test kit.In the second part, we constructed a fluorescent sensor1H-imidazo[4,5-b]Phenazine derivatives for recognition of ions. The sensor displayed high selectivityand sensitivity for iron ion in DMSO solution, which served as an ON–OFF typesensor. The recognition mechanism of the sensor toward Fe3+was evaluated by MS,IR and XRD. Test strips were prepared by immersing filter papers (3×1cm2) into the DMSO solution of the sensor which exhibits a good selectivity to Fe3+. Therefore, thesensor has potential applications in physiological and environmental systems for Fe3+detection.In the third part, we have presented a recyclable fluorescent sensor of Fe3+andH2PO4-based on1H-Imidazo[4,5-b]Phenazine derivatives. The sensor displayed highselectivity and sensitivity for iron () ions, which served as an ON OFF type sensor.Consequently, the product of the ensemble was an excellent indicator for H2PO4-ionsover other common ions in the same media without interference, constituting anON OFF ON type fluorescence recognition system. In addition, test strips based onthe sensor were fabricated. We believe the test strips could act as a convenient andefficient Hg2+test kit.In the fourth part, we have designed and synthesized a long wavelength emissionfluorescent (612nm) chemosensor based on1H-Imidazo[4,5-b]Phenazine derivative,the fluorescent sensor for sequential recognition of two anions (Fe3+and H2PO4-)based on the displacement approach. The sensor displayed high selectivity andsensitivity for iron() ions, which served as an ON OFF type sensor. And the teststrips based on2-Pyridine-1H-imidazo[4,5-b]phenazine were fabricated, which couldact as a convenient and efficient Fe3+test kits. Consequently, the product of theensemble was an excellent indicator for H2PO4-ions over other common ions in thesame media without interference, constituting an ON OFF ON type fluorescencerecognition system. Therefore, the sensor has potential applications in environmentalsystems for Fe3+and H2PO4-ion detection.In the fifth part, we have presented tow kinds of new long wavelength emissiondihydrogen phosphate chemosensors according to the twisted intramolecular chargetransfer (TICT) mechanism based on2-Pyridine-1H-imidazo[4,5-b]phenazine andCd2+, Zn2+complex. The tow sensors showed both fluorescent and colorimetricselectivity for H2PO4-in DMSO/H2O (8:2, v/v) HEPES buffer solutions. To the bestof our knowledge, this is the first time that a long wavelength emission fluorescentchemosensor with high selectivity for H2PO4-was designed based on2-Pyridine-1H-imidazo[4,5-b]phenazine and Cd2+, Zn2+complex. Thus, it is believedthat this receptor will have a role to play in the sensing, detection, and recognition of H2PO4-ions. In addition, test strips were fabricated, which exhibits a good selectivityto H2PO4-as in solution. We believe the test strips could act as a convenient andefficient H2PO4-test kits.In the last part, a simple4-amino-3-hydroxynaphthalene-1-sulfonic acid isdemonstrated to fluorescently sense CN-in water according to the mechanism ofsupramolecular self-assembly. This work provides a novel approach for the selectiverecognition of CN-anions. Thus, this good example might stimulate wide interest ofscientists for further development of new chemosensors possessing excellentperformance with the guidance of the supramolecular self-assembly mechanism. Inaddition, test strips based on S4were fabricated, which also exhibits a good selectivityto CN-as in water. We believe the test strips could act as a convenient and efficientCN-test kit.