Molecular Orbital Theoretical Study on the Conformation and Chemical Reactivity of Insecticidal 0,0-Diethylphenylphosphate Derivatives

살충성(殺蟲性) 0,0-Diethylphenylphosphate 유도체(誘導體)의 형태(形態)와 반응성(反應性)에 관(關)한 분자궤도론적(分子軌度論的) 연구(硏究)

Molecular orbital theoretical study on the stability of conformations and chemical reactivity of 0,0-diethylphenylphosphate derivatives were carried out by EHT and CNDO/2 molecular orbital calculation method. The results shown that the dipole moment(${\mu}$) and total energies of the ${\theta}=90^{\circ}$ conformer were ${\mu}=3.185D\;&\;E_t=-162.6479(au)$ and also that of the ${\theta}=0^{\circ}$ conformer were ${\mu}=5.596D\;&\;E_t=-162.4013(au)$, respectively. Therefore, the values of ${\mu}\;&\;E_t$ of the ${\theta}=90^{\circ}$ conformer were much smaller than that of the ${\theta}=0^{\circ}$ conformer. The form with angle of rotation ${\theta}=90^{\circ}$ of phenyl ring was shown to be most stable and this was interpreted in terms of electrostatic and steric effect. 0,0-diethylphenylphosphate derivatives are predicted to increase both charge and orbital controlled $SN_2$ reactivity of the electron withdrawing substituent reduces the HOMO & LUMO energy, while the electron withdrawing substituent due to increase in positive charge of phosphorus atom of phosphate molecule.

대표적인 유기인계 살충성 0,0-diethylphenylphosphate 유도체의 양자 약리학적 특성에 대한 이해를 도모하기 위하여 EHT와 CNDO/2분자궤도 함수 계산방법으로 0,0-diethylphenylphosphate 분자의 형태와 에너지성분 및 반응성을 검토하였다. 형태이성체들에 대한 전체에너지($E_r$)와 쌍극자 능율값(${\mu}$)을 계산한 바, ${\theta}=0^{\circ}$보다 ${\theta}=90^{\circ}$인 형태가 ${\mu}=2.4D$와 $E_r=181.5(EHT)$ 및 $E_r=154.8kcal/mol(CNDO/2)$만큼 작은 값을 나타낼뿐만 아니라, steric factor도 작아지므로 ${\theta}=90^{\circ}$형태가 가장 알짜 안정화된 형태이었으며 ${\theta}=90^{\circ}$형태에 대한 HOMO, LUMO에너지, 알짜 전하, overlap population, AO계수 등을 계산하였다. Hammett식에 적용하며 치환기 효과를 검토한 결과, 전자를 끄는 치환기에 의하여 P원자의 양하전이 증가하는 coulomb term 효과와 LUMO에너지가 낮아지는 frontier orbital term 효과가 같은 경향으로 이루어저 charge-control-led reaction과 orbital-controlled reaction이 일어나는 $SN_2$형의 반응성을 갖는다는 사실을 알았다.