Internal Modification Method Of Macrocycles Based On Meso Hydroxylation Of Porphyrin

Porphyrins and porphyrinoids play important roles in nature.Moreover,their excellent optical and electrical properties have been widely applied in non-linear optical materials,photodynamic therapy,dye-sensitized solar cells.The hydroxylation of porphyrins and porphyrinoids is an important method for modifying such compounds.After hydroxylation,the reactivity,water solubility,biocompatibility and many other properties of porphyrinoids can be significantly changed,thereby further expanding the scope of application.In addition,meso-hydroxyporphyrins can be further oxidized to give the corresponding meso-oxylporphyrins which serves as remarkably stable organic radicals in air.Their unique magnetic properties and NIR absorptions make them promising materials in the fields of molecular magnets,quantum information and biological imaging.In recent years,some hydroxylation methods of porphyrins have been reported,but the substrate scope of these methods remains to be raised.In this dissertation,a mild and simple method for introducing hydroxyl group into meso position of 2,18-substituted porphyrins was developed.These 3,7-substituted-5-hydroxyporphyrins can be further oxidized to corresponding 5-oxy radical porphyrins.The above strategy can also be applied to porphyrin arrays with meso-H,where hydroxyl/oxygen radicals can be introduced into the meso position of the porphyrin within the cavity.The mainbody of this dissertation includes:(1)Using classical Pd-catalyzed cross-coupling strategy to prepare 2,18-disubstituted porphyrins,exploring their reaction with phenyliodine-bis(trifluoroacetate)(PIFA)to synthesize a variety of 3,7-disubstituted-5-hydroxyporphyrins.PbO₂ is used to oxidize these hydroxyporphyrins to achieve 3,7-disubstituted-5-oxylporphyrins.The UV/Vis/NIR absorption spectra of these radicals show that the position of the NIR absorption peak can be adjusted by changing substituents on 3and 7-position.Among them,the NIR absorption peak of 3,7-bis(4-methoxyphenyl)-5-oxy radical porphyrin is red-shifted to 1750nm.Furthermore,electrochemical data demonstrates the narrow gaps of this type of compounds between the first oxidation and reduction waves.(2)2,18-diboryl-5,10,15-tris(3,5-di-tert-butylphenyl)porphyrinato nickel(II)and 2,18-diiodo/dibromo-5,10,15-tris(3,5-di-tert-butylphenyl)porphyrinato nickel(II)were employed as raw materials to react with various building blocks to construct corresponding cyclic porphyrin arrays.Based on the method above,the meso-H inside the cavity is modified to yield the corresponding cyclic meso-hydroxyl porphyrin arrays.Since the increasing of the volume of the cavity leads to the enhancement of the reactivity of PIFA on meso-C of porphyrin,the smoothness the hydroxylation reaction is strongly affected by the volume of the cavity in the porphyrin array.When PIFA is used to react with the monohydroxylated intermediates of the p/m-phenylene bridge,the dihydroxylated products can not be produced;instead the porphyrin unit bearing the hydroxyl group undergoes a ring-opening reaction,resulting in a partially degradation product.The hydroxylated substances in these cyclic porphyrin arrays can also be further oxidized by oxidants to generate corresponding meso-oxy radicals.