Synthesis, Characterization And Performances Of Novel Sulfur-containing Porphyrazines Used In Environmental Photocatalysis

Environmental pollution has increasingly becoming a serious problem for human beingswith the industrial and social development. Advancements of technology allow scientistsactively to seek methods to reduce pollution and improve our environment. Scientists havefound that tetraazaporphyrin and its derivatives can be used as a green photocatalyst tosimulate metal oxide enzyme to degrade toxic and refractory organic pollutants in aquaticenvironment since the past half century. This green and efficient biomimetic photocatalyticmethod shows excellent prospect, hence we have studied electron-rich tetraazaporphyrin andits metal complexes in depth.Tetraazaporphyrin, or porphyrazine（abbr. Pz）, whose macrocycle is made up of fourpyrrole rings linking together by four nitrogen atoms to build up a tight thick macrocyclicstructure and delocalized π-conjugate electron system, has excellent physicochemicalproperties. The presence of the heteroatom S in the porphyrin skeleton will impact on thephysicochemical properties of Pz due to p-π conjugation. In recent years, researchers haveinvestigated a lot of Pzs containing donor sulfur-containing moieties and Pzs that peripherallybinded with selenodiazole-fused moieties or amino substitutents in the field of basic research.However, there is rare study on the Pz with thioethers coexisting harmoniously with aminogroups outside porphyrazinic skeleton in published papers.In this paper, we sought to combine thio-butyl groups and the1,2,5-selenodiazole ringwith Pz macrocycle through cyclotetramerization of their corresponding precursors. Thesenew porphyrazinic macrocycles are expected to show unique electrical, optical properties andphysiological properties of the electron transfer system owing to the external softelectron-rich atoms（S, Se） neighboring on this Pz core and large delocalized conjugate system.What’s more, this asymmetrical selenadiazole-fused Pz can be used as a raw material tosynthesize new porphyrazinic macrocycles through deselenization, this will open up apromising synthesis pathway to yield new Pzs and provide a feasible way to the Pzaggregation.In the synthesis process, we occasionally get two incomplete Pzs which lost abridge-nitrogen and a Pz with a sulfoxide-containing group. We conducted a detailedcharacterization and confirmed their structure of these three novel compounds.The specific study contents of this paper can be summarized in the following aspects:1. The （selenoamino） maleonitrile and bis（butylthio）maleonitrile are reacted together asprecursors through cyclotetramerization. A novel Pz,7,8,12,13,17,18-hexakis（4-butylthio）-（1,2,5） selenodiazolo-porphyrazine and its Zn complex, were synthesizedconsequently. This freebase porphyrazine was well characterized by IR,¹H NMR,¹³CNMR, UV-vis and MS, etc.2. We got a full symmetry Pz with the lack of bridge-nitrogen atom and an incomplete asymmetric selenodiazole-fused Pz without a bridge-nitrogen atom and a hexakis（4-butylthio）-（1,2,5） selenodiazolo-Pz with a single sulfoxide after purification, theywere characterized by¹H-NMR,¹³C-NMR, IR, UV-vis, MS.3. We directly synthesized the hexakis（4-butylthio）-（1,2,5）selenodiazolo-Pz containing asingle sulfoxide and its Zn complex with full symmetry Octakis（butylthio）Pz and3-chloroperoxybenzoic acid（m-CPBA） as raw materials, we characterized them by¹H-NMR,¹³C-NMR, UV-vis, IR.4. Preliminary exploration was studied on the degradation performance of Rhodamine B（RhB） by selenium Pz zinc complex in the light condition.5. We studied the RhB degradation catalyzed by Bu₄PzO@Al₂O₃in no O2and lightconditions. As a result, a possible mechanism that Bu₄Pz catalyse the substratedegradation has been proposed and a partial validation has been taken.