Su ve Benzen Çözeltilerinde 5,5-Dimetil-1-Pirolin N-Oksit’in Bazı Radikal Ürünlerinin Teorik İnce Yapı Çiftlenim Sabitleri

Year 2016, Volume: 11 Issue: 2, 61 - 74, 02.12.2016

Mustafa Karakaya Şefik Nardalı Fatih Ucun

Abstract

Su ve benzen çözeltilerinde
5,5-dimetil-1-pirolin N-oksit
(DMPO)’nun bazı radikal ürünlerinin temel hal optimize yapıları, 6-31G (d,p),
6-311++G (d,p), LanL2DZ, LanL2MB ve SDD setlerinde Yoğunluk Fonksiyon Teori (DFT/B3LYP,
DFT/B3PW91 ve DFT/PBEPBE) ve Hartree Fock (HF) metotları kullanılarak
hesaplandı. Tuzaklanmış radikaller olarak, 
H, OH, O(CH₂)(CH₃) ve OC(CH₃)₃ kullanıldı.
Tuzaklanan radikallerin hesaplanan izotropik ince yapı çiftlenim sabitlerinin,
deneysel veriler uyum içinde olduğu görüldü. Azot radikalinin β protonundan kaynaklı aşırı ince yapı
çiftlenim sabitinin, azota bağlı oksijen çekirdeğindeki zıt spin yoğunluğundan
etkilendiği görüldü. Elde edilen bütün teorik sonuçlardan, kullanılan radikaller
için ince yapı hesaplamalarında, DFT(B3LYP)/LANL2MB setinin diğer setlere kıyasla
deneysel veriler ile daha uyumlu sonuçlar verdiği tespit edildi. Ayrıca
çalışma, bütün radikal ürünleri için teorik geometrik parametreler, bağlanma
enerjileri, atomik spin yoğunlukları ve hiper konjugatif etkileşim enerjileri
ile zenginleştirildi.

Keywords

Aşırı ince yapı sabiti, DMPO, radikal, ESR, DFT

Theoretical Hyperfine Coupling Constants of Some Radical Adducts to 5,5-Dimethyl-1-Pyrroline N-Oxide in Water and Benzene Solutions

Abstract

The ground
state optimized structures of some radical adducts of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) in water and benzene
solutions have been determined by using Density Functional Theory (DFT/B3LYP, DFT/B3PW91 ve DFT/PBEPBE)
ve Hartree Fock (HF) methods with 6-31G (d,p), 6-311++G (d,p),
LanL2DZ, LanL2MB and SDD levels. As trapped radicals, H, OH, O(CH₂)(CH₃)
and OC(CH₃)₃ have been used. The calculated isotropic
hyperfine coupling constants of all the trapped radicals have been seen to be
agree with the corresponding experimental data. The hyperfine coupling constant
due to the β proton of nitroxide
radical is concluded to be effected with the opposite spin density of oxygen
nucleus bonded to the nitrogen. From all the calculated data it was obtained
that on the hyperfine calculations the DFT (B3LYP) LANL2MB level is superior
relative to the other levels for the used radicals. Also, the study has been
enriched by the computational of the geometrical parameters, binding energies,
atomic spin densities and hyper conjugative interaction energies for all the
radical adducts.

Keywords

Hyperfine constant, DMPO, radical, ESR, DFT

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