Objectives: The aim of this research work was to theoretically calculate the pKa value of boric acid in aqueous solution by theoretical methods atT=298.15 K.Materials and Methods: Boric acid has antifungal and antiviral properties. It is used in various prescription pharmaceutical products. The ab initioand density functional theory (DFT) methods were used in this research work.Results: To explain the determined acidic dissociation constant, the various molecular conformations and solute-solvent interactions of the speciesof boric acid were considered. The basis set at the B3LYP/6-31+G (d) level of theory was selected for DFT calculations. We analyzed the formationof intermolecular hydrogen bonds between several species of boric acid and water molecules through Tomasi’s method.Conclusion: The result showed that there was comparable agreement between the experimentally and theoretically determined pKa values for boricacid.
Amaç: Bu araştırmanın amacı, borik asidin sulu çözeltisinin pKa değerini teorik olarak T= 298,15 K’da hesaplamaktır. Gereç ve Yöntemler: Borik asit antifungal ve antiviral özelliklere sahiptir. Çeşitli reçeteli farmasötik ürünlerde kullanılır. Bu araştırma çalışmasında ab initio ve yoğunluk fonksiyonel teorisi (DFT) yöntemleri kullanılmıştır. Bulgular: Belirlenen asit disosiyasyon sabitini açıklamak için, borik asit türlerinin çeşitli moleküler konformasyonları ve çözünen-çözücü etkileşimleri göz önünde bulunduruldu. B3LYP / 6-31 + G (d) teori düzeyindeki temel set DFT hesaplamaları için seçilmiştir. Tomasi metodu ile çeşitli borik asit türleri ve su molekülleri arasında intermoleküller hidrojen bağlarının oluşumu analiz edildi. Sonuç: Çalışmanın sonucu, borik asit için deneysel ve teorik olarak belirlenen pKa değerleri arasında karşılaştırılabilir bir uyum olduğunu göstermiştir.
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1. Boeseken J. The use of boric acid for the determination of the configuration of carbohydrates. Adv Carbohydr Chem. 1949;4:189-210.
2. Ishii Y, Fujizuka N. A fatal case of acute boric acid poisoning. J Toxicol: Clinical Toxicology. 1993;31:345-352.
3. Goldbloom RB, Goldbloom A. Boric acid poisoning. J Pediatr. 1953;43:631-643.
4. Krieger R. Handbook of Pesticide Toxicology, Vol 2,. San Diego; Academic Press; 2001:1434.
5. Vaziri ND, Oveisi F, Culver BD, Pahl MV, Andersen ME, Strong PL, Murray FJ. The effect of pregnancy on renal clearance of boron in rats given boric acid orally. Toxicol Sci. 2001;60:257-263.
6. Kiani F, Khanlarzadeh B, Tahermansouri H. Ab Initio and density functional theory study on ionization of betahistine and cimetidine nano drug in aqueous solution. Farmacia. 2016;64:3-8.
7. Nag A, Dey B. Computer-aided drug design and delivery systems. Pharmacology. New York; McGraw-Hill; 2011.
8. Kibbey CE, Poole SK, Robinson B, Jackson JD, Durham D. An integrated process for measuring the physicochemical properties of drug candidates in a preclinical discovery environment. J Pharm Sci. 2001;90:1164-1175.
9. Zhoo L. Agilent Technologies. Inc: Analysis of food additives in beverages using syringe filter filtration and HPLC. USA; 2013.
10. Manov GG, DeLollis NJ, Acree SF. Ionization constant of boric acid and the pH of certain borax-chloride buffer solutions from 0 to 60°C. J Res Natl Bur Stand (U.S.). 1944;33:287-306.
11. Arcis H, Ferguson J, Applegarth LMSGA, Zimmerman GH, Tremaine PR. Ionization of boric acid in water from 298 K to 623 K by AC conductivity and Raman spectroscopy. J Chem Thermodyn. 2017;106:187-198.
12. Dickson AG. Thermodynamics of the dissociation of boric acid in synthetic seawater from 273.15 to 318.15 K. Deep Sea Research Part A. Oceanographic Research Papers. 1990;37:755-766.
13. Almarcha C, Honi YR, de Decker Y, Trevelyan PMJ, Eckert K, de Wit A. Convective mixing induced by acid-base reactions. J Phys Chem. 2011;115:9739-9744.
14. Stephens PJ, Devlin FJ, Chabaloeski CF, Frisch MJ. Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields. J Phys Chem. 1994,98:11623-11627.
15. Soler JM, Artacho E, Gale JD, Garcia A, Junquera J, Ordejon P, Sanchez-Portal D. The siesta method for ab initio order-N materials simulation. J Phys: Condensed Matter. 2002;14:2745-2779.
16. Greengard L. Fast algorithms for classical physics. Science. 1994;265:909-914.
17. Hockney RW, Eastwood JW. Computer Simulation Using Particles. Bristol: Institute of Physics Publishing; 1998.
18. Car R, Parrinello M. Unified approach for molecular dynamics and density-functional theory. Phys Rev Lett. 1985;55:2471.
19. Kiani F, Rostami AA, Sharifi S, Bahadori A. Calculation of acidic dissociation constants of glycylglycine in water at different temperatures using ab initio methods. J Mol Struc: THEOCHEM. 2010;956:20-25.
20. Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Zakrzewski VG, Montgomery Jr JA, Stratmann RE, Burant JC, Dapprich S, Millam JM, Daniels AD, Kudin KN, Strain MC, Farkas O, Tomasi V, Barone M, Cossi R, Cammi B, Mennucci C, Pomelli C, Adamo S, Clifford J, Ochterski J, Petersson GA, Ayala PY, Cui Q, Morokuma K, Malick DK, Rabuck AD, Raghavachari K, Foresman JB, Cioslowski J, Ortiz JV, Stefanov BB, Liu G, Liashenko A, Piskorz P, Komaromi I, Gomperts R, Martin RL, Fox DJ, Keith T, Al-Laham MA, Peng CY, Nanayakkara A, Gonzalez C, Challacombe M, Gill PMW, Johnson B, Chen W, Wong MW, Andres JL, Gonzalez C, Head-Gordon M, Replogle ES, Pople JA. Gaussian 98, revision A.6. Pittsburgh; Gaussian, Inc.; 1998.
21. Miertus S, Tomasi EJ. Approximate evaluations of the electrostatic free energy and internal energy changes in solution processes. Chem Phys. 1982;65:239-245.
22. Goldberg RN, Kishore N, Lennen RM. Thermodynamic quantities for the ionization reactions of buffers. J Phys Chem Ref Dat. 2002;31:231-370.
23. Jeffrey GA. An Introduction to Hydrogen Bonding. Oxford; Oxford University Press; 1997.