Kinetic Studies of the Solvolyses of 4-Nitrophenyl Phenyl Thiophosphorochloridate

Bulletin of the Korean chemical society

Han Joong Koh¹  Suk Jin Kang¹ 

关键词: 4-Nitrophenyl phenyl thiophosphorochloridate;    Extended Grunwald-Winstein equation;    SN2 mechanism;    Kinetic solvent isotope effects;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

Rates of solvolyses of 4-nitrophenyl phenyl thiophosphorochloridate (4-NO₂PhOP(S)(Cl)OPh, 1) in ethanol, methanol, and aqueous binary mixtures incorporating ethanol, methanol, acetone, and 2,2,2-trifluroethanol (TFE) are reported. Thermodynamic parameters were determined at several temperatures in three representative solvents. The extended Grunwald-Winstein equation was applied to 29 solvents and the correlation coefficient (R) showed 0.959. The sensitivities (l = 1.37 and m = 0.62) are similar to those obtained for diphenyl thiophosphorochloridate ((PhO)₂PSCl, 2), diphenyl phosphorochloridate ((PhO)₂POCl, 3), diphenyl phosphinic chloride (Ph2POCl, 4), and diphenyl thiophosphinic chloride (Ph2PSCl, 5). The solvolytic reaction mechanism of 4-nitrophenyl phenyl thiophosphorochloridate (1) is suggested to be proceeded a S_N2 process as previously reported result. The activation enthalpies are shown as slightly low as ツH× = 9.62 to 11.9 kcal·mol^-1 and the activation entropies are shown as slightly high negative value as ツS× = -34.1 to -44.9 cal·mol^-1·K^-1 compared to the expected SN2 reaction mechanism. Kinetic solvent isotope effects are accord with a typical SN2 mechanism as shown in the range of 2.41 in MeOH/ MeOD and 2.57 in H₂O/D₂O solvent mixtures.

【 授权许可】

Unknown