Structure Elucidation of Schiff Base-Containing Compound by Quantum Chemical Methods

Öz

Schiff bases, named after German chemist Hugo Schiff, are compounds with a central functional group containing an imine or azomethine (-C=N-) linkage. They have been extensively studied in various fields such as organic synthesis, coordination chemistry, and medicinal chemistry due to their diverse properties and wide range of applications. Schiff bases have been extensively utilized in scientific research since their discovery due to their multifaceted properties. The intense focus on Schiff bases in the literature stems from their versatile characteristics. This study aims to elucidate the theoretical physical and chemical properties of a compound containing a Schiff base, (Z)-4-(2,6-dichlorophenyldiazenyl)-6-{[1,3-dihydroxy-2-(hydroxymethyl)propan-2-ylamino]methyl}-2-methoxycyclohexa-2,4-dienone, whose structure was previously experimentally elucidated by X-ray diffraction. GaussView 4.1.2 and Gaussian 03W were employed to determine the compound’s physical and chemical properties. Based on experimental and theoretical geometric parameters, the compound was observed to possess a keto-amine tautomeric form and exhibit high aromaticity, as evidenced by computational HOMA indices. The compound’s electrophilic and nucleophilic regions were illuminated based on identified frontier molecular orbitals and electronic parameters derived from these orbitals, indicating its stability. These findings were supported by molecular electrostatic potential maps, revealing electrophilic and nucleophilic attack regions on the structure. Polarizability anisotropy (∆α) and hyperpolarizability (β) values were calculated as 73.3003Å3 and 5.46547x10-29 cm5 e.s.u.-1, respectively, indicating the structure’s high polarizability feature. Natural bond orbital analysis elucidated the nature of intramolecular hydrogen bonding and delocalization between electron-donor and acceptor-type orbitals. Finally, Mulliken charge analysis supported electrophilic and nucleophilic binding regions within the structure.

Anahtar Kelimeler

• Schiff base
• physical and chemical properties
• quantum mechanical calculations

Kaynakça

1. [1] S. Başak, “Antitümor ve antikanserojen erkili bazı schiff bazı moleküllerinin moleküler yerleştirme yöntemi ile incelenmesi”, Yüksek Lisans Tezi, Sinop Üniversitesi, Fen Bilimleri Enstitüsü, 2023.
2. [2] B. Koşar, “4-Metoksi ve 3-hidroksi salisilaldehit türevi bazı schiff bazlarının yapısal özelliklerinin deneysel x-ışını kırınımı ve kuramsal yöntemlerle incelenmesi”, Doktora Tezi, Ondokuz Mayıs Üniversitesi, Fen Bilimleri Enstitüsü, 2008.
3. [3] A. T. Peters, and H. S. Freeman, “Colour Chemistry: The Design and Synthesis of Organic Dyes and Pigments (Ettore Majorana International Science Series)”, Colour Chemistry, pp. 193-223, 1991.
4. [4] B. K. Çelikateş, M. Baysal, “Gıda Azo Boyalarının Erkek Reprodüktif Toksisitesi Yönünden Değerlendirilmesi”, Ankara Eczacılık Fakültesi Dergisi, vol. 48(3), 1236-1247, https://dx.doi.org/10.33483/jfpau.1481724, 2024.
5. [5] D. R. Williams, “Metals, Ligands, and Cancer”, Chemical Reviews, vol. 72 (3), 203-213, 1972.
6. [6] A. Özek, Ç. Albayrak, M. Odabaşoğlu, and O. Büyükgüngör, “(Z)-4-(2,6-Dichlorophenyldiazenyl)-6-{[1,3-dihydroxy-2-(hydroxy-methyl)propan-2-ylamino]methylene}-2-methoxycyclohexa-2,4-dienone andthe 3-methoxyphenyldiazenyl and 4-methoxyphenyldiazenyl analogues”, Acta Crystallogr. C, vol. 62, pp. o173-o177, 2006.
7. [7] Gaussian 03, Wallingford CT. [Online]. Available: https://gaussian.com/, 2004.
8. [8] C. C. Ersanlı, G. Kaya Kantar, and S. Şaşmaz, S. “Crystallographic, spectroscopic (FTIR and NMR) and quantum computational calculation studies on bis(2-methoxy-4-((E)-prop-1-enyl)phenyl)oxalate”, Journal of Molecular Structure, vol. 1143, pp. 318-327, https://doi.org/10.1016/j.molstruc.2017.04.032, 2017.

9. [9] Öztürk, S., Aycan, T., Demircioğlu, Z., Ersanlı, C. C. (2023). Quantum Mechanical Calculations, Hirshfeld Surface Analysis, Molecular Docking, ADME and Toxicology Studies of the Ethyl 4-chloro-2-[(4-nitrophenyl)hydrazono]-3-oxobutrate Compound. International Scientific and Vocational Studies Journal, 7(2), 109-121. https://doi.org/10.47897/bilmes.1385170.
10. [10] B. K. Kırca, Ç. Albayrak Kaştaş, and C. C. Ersanlı, “Molecular and electronic structures of two new Schiff base compounds E-2-bromo-6-(2-bromo-4-methylphenylimino)methyl-4-chlorophenol and E-2-bromo-6-(4-bromo-3-methylphenylimino)methyl-4-chlorophenol”, Journal of Molecular Structure, vol. 1241, 130643, https://dx.doi.org/10.1016/j.molstruc.2021.130643, 2021.
11. [11] H. D. Raihana, K. Karthick, S. Kamalesu, A. Babu, and K. Swarnalatha, “A new tetradentate Schiff base of N, N’-bis(3, 5-diiodosalicylidene)-1,2-phenylenediamine: Spectral aspects, Hirshfield surfaces, DFT computations and molecular docking”, Journal of Molecular Structure, vol. 2146, 133217, https://doi.org/10.1016/j.molstruc.2022.133217, 2021.
12. [12] C. Bosshard, K. Suttur, O. Pretre, M. Flörsheimer, P. Kaatz, and P. Günter, “Second-Order Nonlinear Optical Organic Materials: Recent Developments”, Springer Berlin Heidelberg, 72, 72 p. https://doi.org/10.1007/978-3-540-49713-4_3, 2000.
13. [13] D. Sajan, J. Hubert, V. S. Jayakumar, and J. Zaleski, “Structural and electronic contributions to hyperpolarizability in methyl p-hydroxy benzoate”, Journal of Molecular Structure, vol. 785 no. (1-3), pp. 45-53, 2005.
14. [14] Y. X. Sun, Q. L. Hao, W. X. Wei, Z. X. Yu, L. D. Lu, X. Wang, and Y. S. Wang, “Experimental and density functional studies on 4-(3, 4-dihydroxybenzylideneamino) antipyrine, and 4-(2, 3, 4-trihydroxybenzylideneamino) antipyrine”, Journal of Molecular Structure: THEOCHEM, vol. 904, no. (1-3), pp. 74-82, 2009.
15. [15] M. Snehalatha, C. Ravikumar, I. H. Joe, N. Sekar, and V. S. Jayakumar, Spectroscopic analysis and DFT calculations of a food additive Carmoisine, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 72, no. 3, pp. 654-662, 2009.