Electronic effects on normal and abnormal acyclic, cyclic-saturated and cyclic-unsaturated diaminocarbenes at DFT

سال انتشار: 1397
نوع سند: مقاله کنفرانسی
زبان: انگلیسی
مشاهده: 259

متن کامل این مقاله منتشر نشده است و فقط به صورت چکیده یا چکیده مبسوط در پایگاه موجود می باشد.
توضیح: معمولا کلیه مقالاتی که کمتر از ۵ صفحه باشند در پایگاه سیویلیکا اصل مقاله (فول تکست) محسوب نمی شوند و فقط کاربران عضو بدون کسر اعتبار می توانند فایل آنها را دریافت نمایند.

استخراج به نرم افزارهای پژوهشی:

لینک ثابت به این مقاله:

شناسه ملی سند علمی:

IRANCC20_181

تاریخ نمایه سازی: 28 اردیبهشت 1398

چکیده مقاله:

Carbenes are sextet neutral divalent carbon species. The two nonbonding-unpaired electrons of a triplet carbene have parallel spins with a linear or bent geometry, whilethose of a closed shell singlet carbene appear anti-parallel in an σ or 2pπ orbital. Carbenes are an important class of reactive intermediates. Diaminocarbenes arecarbenes with two nitrogen atoms in neighboring of carbene center (acyclic or cyclic forms) [1,2]. Before, we studied on steric effects on normal and abnormal acyclic,cyclic-saturated and cyclic-unsaturated diaminocarbenes at DFT. We used DFT calculations (M06/6-311++G** level) to attain electronic effects on the multiplicity, stability, and reactivity of normal and abnormal 2,4-disubstituted diaminocarbenes with acyclic, cyclic-saturated and cyclic-unsaturated structures (1R, 1 R; 2R, 2 R; and 3R, 3 R; respectively), (R = NH2, OH, OMe, SH, Ph, CN, CF3, NO2). All optimized structures are stable singlet ground states. In both electron withdrawing and releasing substituents, going from acyclic to cyclic structure, because of cyclization and aromatization, singlet-triplet energy gap (ΔES-T), HOMO-LUMO energy gap (ΔEH-L), and proton affinity (PA) increase (except 3 R). Going from acyclic to cyclic and unsaturated structures, Nucleophilicity (N) decreases, and Electrophilicity (ω) increases.

نویسندگان

Neda Khorshidvand

Department of Chemistry, Faculty of Science, Tarbiat Modares University, Tehran, Iran

Mohamad Zaman Kassaee

Department of Chemistry, Faculty of Science, Tarbiat Modares University, Tehran, Iran