4-Florobenzil Alkolün Konformasyon ve Orbital Etkileşimlerinin DFT Metodu ile Teorik Çalışması

Yıl 2019, Cilt: 23 Sayı: 3, 797 - 804, 25.12.2019

Nihal Kuş Saliha Ilıcan

https://doi.org/10.19113/sdufenbed.544859

Öz

Bu
çalışmada, 4-florobenzil alkol (4FBA) molekülünün konformasyonları
DFT/B3LYP/6-311++G(d,p) metodu kullanılarak çalışılmıştır. Bileşiğin optimize
edilmiş geometrisi ve enerjileri belirlenmiştir. 4FBA, minimum enerjili ve
kararlı yapıda iki konformasyona (4FBA-I ve 4FAB-II) sahiptir. İki konformasyon
arasındaki bağıl elektronik enerji değeri 3,6 kJ mol^-1 olarak
hesaplanmıştır. Bariyer enerjisi 2,49 kJ mol^-1 gibi çok küçük bir
değer olarak hesaplanmıştır. Bu durum, konformasyonel bir gevşemeye neden
olarak, en kararlı duruma geçişi sağlayabilir. 4FBA-I ve 4FBA-II formlarının
stabilizasyon enerjileri ve donör-akseptör etkileşimleri doğal bağ orbital
(NBO) analizi ile yapılmıştır. NBO etkileşimlerinin yanında benzen halkasının
karbon atomları üzerinden elektronik delokalizasyonun olduğu gözlenmiştir. Bu
durum, p→p* orbital
etkileşimi ile açıklanabilir. Ayrıca, molekülün en yüksek dolu moleküler
orbitali (HOMO) ve en düşük boş moleküler orbitali (LUMO) arasındaki enerji
farkı hesaplanmış, 4FBA-I ve 4FBA-II için sırasıyla 6,038 ve 6,142 eV olarak
bulunmuştur.

Anahtar Kelimeler

4-Florobenzil Alkol, DFT, NBO, Orbital etkileşimleri

Theoretical Study of Conformational and Orbital Interactions of 4-Fluorobenzyl Alcohol by DFT Method

Öz

In this study, the conformations of 4-fluorobenzyl
alcohol (4FBA) molecule were studied by using DFT/B3LYP/6-311++G(d,p) method.
Optimized geometry and energies of compound were determined. 4FBA has two
conformers (4FBA-I and 4FAB-II) with minimal energies and stable structures.
The difference relative electronic energy of the two conformers were calculated
about 3.6 kJ mol^-1. Barrier energy was calculated as a very small
value (2,49 kJ mol^-1). This may cause conformational relaxation to
the most stable conformer. The stabilization energies and donor-acceptor
interactions of the 4FBA-I and 4FBA-II formations were performed by natural bond
orbital (NBO) analysis. Besides to NBO
interactions, electronic delocalization was observed over carbon atoms of the
benzene ring, and this can be explained by p→p* orbital
interaction. In addition, the energy difference between the highest occupied
molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) was
calculated and found to be 6.038 and 6.142 eV for 4FBA-I and 4FBA-II,
respectively.

Anahtar Kelimeler

4-Fluorobenzyl alcohol, DFT, NBO, Orbital interactions

Kaynakça

• [1] EPA; health and environmental effects document for benzyl alcohol; September 1989.
• [2] Frederick, H., Lovejoy, Jr. M. D. 1982. Fatal benzyl alcohol poisoning in a neonatal intensive care unit. Am. J. Dis. Child., 136(11), 974-975.
• [3] Gershanik, J., Boecler, B., Ensley, H., McCloskey, S., George, W. 1982. The gasping syndrome and benzyl alcohol poisoning. N. Engl. J. Med., 307(22),1384-1388.
• [4] Opinion of the Scientific Committee on Food on Benzyl alcohol, 2002. (Erişim Tarihi: 18.03.2019).http://ec.europa.eu/food/fs/sc/scf/out138_en.pdf.
• [5] Bird, R. G., Nikolaev, A. E., Prat, D. W. 2011. Microwave and UV Excitation Spectra of 4-Fluorobenzyl Alcohol at High Resolution. S0 and S1 Structures and Tunneling Motions along the Low Frequency -CH2OH Torsional Coordinate in Both Electronic States. J. Phys. Chem. A, 115, 11369-11377.
• [6] Guchhait, N., Ebata, T., Mikami, N. 1999. Discrimination of Rotamers of Aryl Alcohol Homologues by Infrared-Ultraviolet Double-Resonance Spectroscopy in a Supersonic Jet. J. Am. Chem. Soc., 121, 5705-5711.
• [7] Mons, M., Robertson, E. G., Simons, J. P. 2000. Intra- and Intermolecular π-Type Hydrogen Bonding in Aryl Alcohols:  UV and IR−UV Ion Dip Spectroscopy. J. Phys. Chem. A, 104 (7), 1430-1437.
• [8] Evangelisti, L., Favero, L. B., Caminati, W. 2010. Rotational spectrum of 2-fluorobenzyl alcohol. J. Mol. Struc., 978, 279-281.
• [9] Frisch, M. J., Trucks, G. W., Schlegel, H. B., Scuseria, G. E., Robb, M. A., Cheeseman, J. R., Scalmani, G., Barone, V., Mennucci, B., Petersson, G. A., Nakatsuji, H., Caricato, M., Li, X., Hratchian, H. P., Izmaylov, A. F., Bloino, J., Zheng, G., Sonnenberg, J. L., Hada, M., Ehara, M., Toyota, K., Fukuda, R., Hasegawa, J., Ishida, M., Nakajima, T., Honda, Y., Kitao, O., Nakai, H., Vreven, T., Montgomery, J. A., Peralta Jr, J. E., Ogliaro, F., Bearpark, M., Heyd, J. J., Brothers, E., Kudin, K. N., Staroverov, V. N., Kobayashi, R., Normand, J., Raghavachari, K., Rendell, A., Burant, J. C., Iyengar, S. S., Tomasi, J., Cossi, M., Rega, N., Millam, J. M., Klene, M., Knox, J. E., Cross, J. B., Bakken, V., Adamo, C., Jaramillo, J., Gomperts, R., Stratmann, R. E., Yazyev, O., Austin, A. J., Cammi, R., Pomelli, C., Ochterski, J. W., Martin, R. L., Morokuma, K., Zakrzewski, V. G., Voth, G. A., Salvador, P., Dannenberg, J. J., Dapprich, S., Daniels, A. D., Farkas, O., Foresman, J. B., Ortiz, J. V., Cioslowski, J., Fox, D. J., 2009, Gaussian 09, Revision A.0.2, Gaussian, Inc., Wallingford CT.
• [10] Becke, A. D. 1988. Density-functional exchange-energy approximation with correct asymptotic behavior. Phys. Rev. A, 38, 3098-3100.
• [11] Clark, T., Chandrasekhar, J., Spitznagel, G. W., Schleyer, P. V. R. 1983. Efficient diffuse function-augmented basis sets for anion calculations. III. The 3-21+G basis set for first-row elements, Li-F. J. Comput. Chem., 4, 294-301.
• [12] Lee, C. T., Yang, W. T., Parr, R. G. 1988. Development of the Colic-Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B, 37, 785-789.
• [13] Reed, A. E., Curtiss, L. A., Weinhold, F. 1988. Intermolecular interactions from a natural bond orbital, donor-acceptor viewpoint. Chem. Rev., 88, 899-926.
• [14] Ruoff, R. S., Klots, T. D., Emilson, T., Gutowski, H. S. Relaxation of conformers and isomers in seeded supersonic jets of inert gases. J. Chem. Phys., 93, 3142-3150.
• [15] Miller, B. J., Kjaergaard, H. G., Hattori, K., Ishiuchi, S., Fujii, M. 2008. The most stable conformer of benzyl alcohol. Chemical Physics Letters, 466, 21-26.
• [16] Alves, T.V., S.-Carballido, L., Ornellas, F.R., F.-Ramos, A. 2016. Hindered rotor tunneling splittings: an application of the two-dimensional non-separable method to benzyl alcohol and two of its fluorine derivatives. Phys Chem Chem Phys., 18(13), 8945-8953.
• [17] Crowder, G. A. 1979. Vibrational Spectra of o-Fluorobenzyl Alcohol. Journal of Fluorine Chemistry, 14, 77-79.
• [18] Liu, C. G., Su, Z. M., Guan, X. H., Muhammad, S. 2011. Redox and Photoisomerization Switching the Second-Order Nonlinear Optical Properties of a Tetrathiafulvalene Derivative Across Six States: A DFT Study. J. Phys. Chem. C, 115, 23946-23954.