Synthesis, Properties And Fountion Studies On Unsymmetrical Porphyrins And Their Compounds

The porphyrins are a class of macrocyclic compounds which contain fourpyrrole rings linked via methine bridges. When two protons of the pyrrolenitrogen atoms are replaced by metal ions, metalloporphyrins have beenobtained. In nature, porphyrins and metalloporphyrins play an important rolein biological activities, for instance, hemoproteins, chlorophylls and vitaminB12. As the particular structure and the nature of the porphyrins, they havepotential applications in the field of photo-electronic conversion ,biomimetic, catalytic materials,gas sensor, solar storage, microanalysis,etc. Today, more efforts have been made on the research of porphyrinderivation.Considerable efforts have been made to synthesize different porphyrinsby modifying them on the porphine. But most of them were symmetrical.Asymmetric synthesis is the popular and forward position in the study of theorganic chemistry today. Asymmetric porphyrins have wide applications inmaterial chemistry, biomimetic chemistry, molecular recognition and catalysis.Nevertheless, lanthanide ions can exhibit long luminescence life times andlarge stoke shifts, but their absorption coefficients are quite low because of theforbidden nature 4f→4f transitions. Porphyrins have relatively rich lightabsorption and emission properties and they have high fluorescent quantumyields. So porphyrins can be used as antenna to form stable lanthanideporphyrin complexes and promising ligands for efficient transfer to lanthanideions and they can efficiently sensitize the emitting states of the lanthanide ionsand improve their intensity. The monoporphyrinate lanthanide complexes wereused as nuclear magnetic resonance (NMR) shift reagents and dipolar probes.They also can be used as CD probes for chirality sensing of biologicalsubstrates.Porphyrin's periphery has 12 active positions, which could link updifferent structures soft side chains. So, we could synthesize new typescompound of liquid crystalline porphyrin with special properties by moleculardesign. Liquid crystalline porphyrin may be used as semiconductor orphotoconductor materials, scientists gave paid close attention to itsphotoeletronic property.In this paper, we synthesized three series and twenty-seven newunsymmetrical porphyrins and their transitional metal and lanthanidecomplexes. These compounds have been characterized by elemental analyses,Uv-vis, IR spectra, NMR, and molar conductance. The structures wereproposed. We also studied their luminescent properties by excitation andemission spectra and proved that porphyrin can be used as efficient sensitizer.Their thermal stabilities were also studied by differential thermal analyses.The liquid crystal properties of one long-chains porphyrin have beenresearched by DSC and polarized microscopic observation and moleculardesign of lanthanide porphyrin liquid crystals was summarized.I. Syntheses of the complexes:In this paper synthesis method of the ligands, rare earth porphyrins, andtransitional metal complexes are introduced, twenty-seven new compounds aredivided three series.Structures of the ligands are follows:NNH NHNR1R2(1) 5-[p-(4-flourobenzoyloxy)]phenyl-10,15,20-triphenyl porphyrin,FBOPTPP,R1= O COF ,R2=H(2) 5-[p-(4-flourobenzoyloxy)-m-ethyloxy]phenyl-10,15,20-triphenylporphyrin, FBOEPTPP,R1= O COF ,R2=OC2H5(3) 5-(4-myristyloxy)phenyl-10,15,20-triphenyl porphyrin, MPTPP,R1= OC(CH2)12CH3O,R2=HStructures of compounds are follows:NN NN R2R1R3M(1) 5-[p-(4-flourobenzoyloxy)]phenyl-10,15,20-triphenyl porphyrin-Acetylacetone-Rare Earth Complexes Ln(FBOPTPP)acac (R1 =O COF , R2=H, R3=acac)and Hydroxy-Rare Earth ComplexesLn(FBOPTPP)OH (R1= O COF , R2=H, R3=OH) ( Ln=Gd,Tb,Dy,Ho,Er)(2) 5-[p-(4-flourobenzoyloxy)-m-ethyloxy]phenyl-10,15,20-triphenylPorphyrin-Acetylacetone-Rare Earth Complexes Ln(FBOEPTPP )acac (R1=O COF , R2=OC2H5, R3=acac, Ln=Tb,Dy,Ho,Er) andtransitional metal complexes (R1 = O COF , R2 = OC2H5, M=Ni,Cu,Zn,Co;when M is Mn,M=Mn+;no R3)(3) 5-(4-myristyloxy)phenyl-10,15,20-triphenyl porphyrin-Acetylacetone-Rare Earth Complexes Ln(MPTPP)acac (R1=OC(CH2)12CH3O, R2=H, R3=acac, Ln=Gd,Tb,Dy,Ho,Er)II. Characterization of complexesThese complexes have been characterized by Elemental analyses, Uv-vis,IR spectra, NMR and Molar Conductance. In conclusion, forPorphyrin-Hydroxy-Rare Earth Complexes, hydroxy and porphyrinsimultaneously were coordinated to the lanthanide ion to form pentadentatehydroxy lanthanide porphyrin complexes while the coordination number ofacetylacetonate porphyrin complexes is six with four N of the porphyrinateand two O of acetylacetonate coordinated to the lanthanide ion. Porphyrintransitional metal complexes are tetradentate complexes, but different metalions with different valence belong to different types of electrolyte. Differentialthermal analysis showed that they all have higher stability and can be storedfor many years as labelled molecules for biology.Ⅲ. Luminescence spectroscopyTheir luminescent properties were studied by excitation and emissionspectra, Quantum yields of Q band (the Φf of the S1→S0) fluorescence of theporphyrins are fluorescence of lanthanide complexes are in the region0.0032～0.191 at room temperature, they were all below 0.21. Porphyrin canbe used as antenna to sensitizes lanthanide ions. They have potentialapplication as luminescence materials.Ⅳ. Liquid CrystalsDSC data and optical textural photo of polarizing microscope indicate theligand has liquid crystalline character while acetylacetonate porphyrinlanthanide complexes have none. molecular design of lanthanide porphyrinliquid crystals was summarized. We hope the conclusion will do help to thestudies in future.