Synthesis And Characterization Of Several Porphyrin-Polyoxometalate Hybrid Materials And Their Photocatalytic Degradation Performance On 2-Chloroethyl Sulfide

To date,mustard gas still poses a great threat to the life safety of people around the world,so the search for materials that can efficiently degrade mustard gas has been a hot topic of interest for researchers.It has been shown that the relatively mild oxidation property of singlet oxygen selectively oxidizes mustard gas and its simulant CEES to nontoxic sulfoxide,so it is extremely important to find materials with high quantum yield of singlet oxygen or methods that can increase the quantum yield of singlet oxygen.The main research results of this paper are as follows:（1）5,10,15,20-tetrakis（4-chlorophenyl）porphyrin(abbreviated as TCl PP,molecular formula C₄₄H₂₆N₄Cl₄)was selected to be combined with Keggin-type polyacid silicotungstate H₄Si W₁₂O₄₀·x H₂O,phosphotungstate H₃PW₁₂O₄₀·x H₂O and Keggin-type polyacid cobalt tungstate potassium K₅Co W₁₂O₄₀·20H₂O,respectively,by electrostatic interaction to prepare three organic-inorganic hybrid materials[C₄₄H₂₈N₄Cl₄]₂[Si W₁₂O₄₀]·1.5C₂H₅OH(abbreviated as TCl PP-Si W₁₂),[C₄₄H₂₇N₄Cl₄]₂[HPW₁₂O₄₀]·C₂H₅OH(abbreviatedasTCl PP-PW₁₂)and[C₄₄H₂₈N₄Cl₄]_1.5[H₂Co W₁₂O₄₀]·1.5（CH₃）₂NCHO(abbreviated as TCl PP-Co W₁₂),the structures of TCl PP-Si W₁₂,TCl PP-PW₁₂ and TCl PP-Co W₁₂ were characterized by IR,thermogravimetric and elemental analysis.The performance of the three materials in homogeneous photocatalytic degradation of CEES in DMF solvent was investigated,and the results showed that the degradation rate of TCl PP-Si W₁₂,TCl PP-PW₁₂ and TCl PP-Co W₁₂ reached88.25%,90.46%and 96.12%,respectively,for CEES at 240 min in DMF.All three hybrids have good reusability and the reaction processes are in accordance with the primary reaction kinetics,with half-life and kinetic constants of 81.73min,-0.0084 min^-1,77.36 min,-0.0089 min^-1 and 54.10 min,-0.013 min^-1 in DMF solvent,respectively.Mechanistic analysis indicates that under the conditions ofλ>400 nm visible light irradiation conditions,TCl PP-Si W₁₂,TCl PP-PW₁₂ and TCl PP-Co W₁₂ undergo oxidation and hydrolysis mechanisms for CEES degradation in DMF solvent,where the oxidation mechanism uses the¹O₂ and O₂^·-generated by the three hybrid materials under light conditions to CEES is selectively oxidized to the nontoxic sulfoxide CEESO.TCl PP-Si W₁₂（Φ=0.025）,TCl PP-PW₁₂（Φ=0.028）and TCl PP-Co W₁₂（Φ=0.038）have higher singlet oxygen quantum yield compared to TCl PP（Φ=0.022）.（2）N-[1,3-dihydroxy-2（hydroxymethyl）propan-2-yl]-4-[10,15,20-tris（4-hydroxyphenyl）porphyrin-5-yl]benzamide(abbreviated as TPPOH-1Tris,molecular formula C₄₉H₃₉N₅O₇)was chosen to be combined with Lindqvist-type polyacid[N（C₄H₉）₄]₃[H₃V₁₀O₂₈]through covalent bonding.An organic-inorganichybridmaterial[N（C₄H₉）₄]₂[C₄₄H₂₉O₃N₄（NHC₂O）（OCH₂）₃(V₆O₁₃)（OCH₂）₃（C₂ONH）N₄O₃H₂₉C₄₄]（referred to as TPPOH@1Lindqvist）was prepared,and it was characterized by IR and UV spectroscopy.The performance of the material in the homogeneous photocatalytic degradation of CEES in methanol solvent was investigated,and the results showed that the degradation rate of TPPOH@1Lindqvist and TPPOH-1Tris for CEES at 240 min in methanol were61.78%and 97.29%,respectively.The hybrid materials have good reusability and the reaction process is in accordance with the primary reaction kinetics,the half-life and kinetic constants of TPPOH@1Lindqvist and TPPOH-1Tris in methanol are 189.4 min,-0.0036 min^-1,46.02 min,-0.015 min^-1,respectively.Mechanistic analysis shows that the degradation of CEES atλ>400 nm visible light irradiation,TPPOH@1Lindqvist degraded CEES in methanol solvent through oxidation and hydrolysis mechanisms,where the oxidation mechanism was to selectively oxidize CEES to nontoxic sulfoxide CEESO using ¹O₂ and O₂^·-produced by TPPOH@1Lindqvist under light conditions.The singlet oxygen quantum yield of TPPOH@1Lindqvist（Φ=0.063）was substantially lower compared to that of TPPOH-1Tris（Φ=0.34）.