PHOTOINDUCED ELECTRON TRANSFER BETWEEN PYRENE/HYDROXYPYRENE AND AROMATIC AMINO ACIDS
Küçük Resim Yok
Tarih
2015
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Işık etkisiyle çalışan elektron transfer sistemleri LEDler ve fotoreseptörler gibi uygulama alanlarına sahiptir. Antenle toplanan fotonik enerji ışıklı elektron transferi veya fotokimyasal bağ organizasyonu ile temel hale aktarılır [1]. Amino asitler zayıf van der Waals ve hidrojen bağı etkileşimleri, görünür bölgedeki geniş geçirgenlik aralığı ve zwitteriyonik yapılar gibi malzeme bilimi açısından önemli özelliklere sahiptirler [2]. Organik optik cihazların verimliliği için gaz fazında ve çözeltide fiziksel özelliklerinin anlaşılması gerekir. Bu çalışmada pren(Py)/1-hidroksipren (PyOH)-aromatik amino asit kompleksleri vakumda ve çözeltide DFT ve TD-DFT yöntemleri ile incelenmiştir. Hesaplamalar Gaussian 09 programında [3] yer alan ?B97XD/6-31G(d,p) seviyesinde yapılmıştır. Pren ve hidroksipren moleküler anten, aromatik amino asitler ise elektron donor olarak seçilmiştir. Sonuçlarımız vakumda daha kararlı kopmleksler oluştuğunu göstermektedir. En kararlı yapılar Triptofan (Trp) için elde edilmiştir. Gazda ve suda önemli yapısal farklılıklar gözlenmiştir. Pren/ hidroksipren-amino asitler arasındaki ?-? etkileşimleri ışıkla transfer tepkimelerini arttırmaktadır. HOMO-LUMO enerjileri yük transferi olduğunu doğrulamaktadır. En belirgin yük transferi Trp kompleksinde HOMO-1 ve LUMO arasında görülmüştür. HOMO ve LUMO arasındaki enerji farkının azalmasının yük transferini kolaylaştırdığı sonucuna varılmıştır
Photoinduced electron transfer systems have optical applications such as sensory photoreceptors and light-emitting diodes. The photonic energy which is harvested by an antenna is transformed into ground state chemistry utilizing photoinduced electron transfer or photochemical bond reorganization [1]. Amino acids often possess particular properties, such as weak van der Waals and hydrogen bonds, wide transparency ranges in the visible regions and zwitterionic nature of the molecules which are very important in materials science [2]. In order to be able to optimize the efficiency of organic optical devices, it is an advantage to understand completely the physical behaviour of compounds in gas phase and in solution. We have studied geometrical structure, electronic structure and optical excitation of pyrene(Py)/1-hydroxypyrene (PyOH) with aromatic amino acids in vacuum and in water using DFT and TD-DFT calculations. The density functional theory (DFT) computations have been performed at ?B97XD/6-31G(d,p) level using Gaussian 09 program [3]. Pyrene and hydroxypyrene were chosen as molecular antenna and aromatic amino acids were chosen as electron donors. Our results show that more stable complexes are formed in vacuum. Tryptophan (Trp) complexes are the most stable among all optimized complexes. Significant geometrical changes have been observed for the optimized complexes between gas phase and water. Pyrene/hydroxypyrene-aminoacid interactions via ?-? stacking promote the photoinduced transfer reactions. Calculated HOMO-LUMO energies confirm that charge-transfer occurs between the molecules. The most significant charge transfer is observed for Trp complexes between HOMO-1 and LUMO. It is concluded that the lowering of highest occupied orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap appears to be cause of its enhanced charge transfer
Photoinduced electron transfer systems have optical applications such as sensory photoreceptors and light-emitting diodes. The photonic energy which is harvested by an antenna is transformed into ground state chemistry utilizing photoinduced electron transfer or photochemical bond reorganization [1]. Amino acids often possess particular properties, such as weak van der Waals and hydrogen bonds, wide transparency ranges in the visible regions and zwitterionic nature of the molecules which are very important in materials science [2]. In order to be able to optimize the efficiency of organic optical devices, it is an advantage to understand completely the physical behaviour of compounds in gas phase and in solution. We have studied geometrical structure, electronic structure and optical excitation of pyrene(Py)/1-hydroxypyrene (PyOH) with aromatic amino acids in vacuum and in water using DFT and TD-DFT calculations. The density functional theory (DFT) computations have been performed at ?B97XD/6-31G(d,p) level using Gaussian 09 program [3]. Pyrene and hydroxypyrene were chosen as molecular antenna and aromatic amino acids were chosen as electron donors. Our results show that more stable complexes are formed in vacuum. Tryptophan (Trp) complexes are the most stable among all optimized complexes. Significant geometrical changes have been observed for the optimized complexes between gas phase and water. Pyrene/hydroxypyrene-aminoacid interactions via ?-? stacking promote the photoinduced transfer reactions. Calculated HOMO-LUMO energies confirm that charge-transfer occurs between the molecules. The most significant charge transfer is observed for Trp complexes between HOMO-1 and LUMO. It is concluded that the lowering of highest occupied orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap appears to be cause of its enhanced charge transfer
Açıklama
Anahtar Kelimeler
Mühendislik, Kimya
Kaynak
Journal of the Turkish Chemical Society, Section A: Chemistry
WoS Q Değeri
Scopus Q Değeri
Cilt
2
Sayı
2
