Quantum-chemical Studies of Several Lanthanide Compounds with Products of Starch Thermal Decomposition
Lanthanide complexes with organic ligands (including hydrocarbons) find application in medicien as luminescent biomarkers for various pathogenic bacteria. At the same time, starch (as a polysaccharide) can serve as a source for carbon nanoparticles (via thermal decomposition) that have very intensive and longliving luminescence, thus such nanoparticles conjunctioned with lanthanides may be used to create more effective medical probes. This paper presents the results of quantum chemical study of geometry and electronic structure parameters of several europium complexes with pieces of starch molecules and starch thermal decomposition products (glucose, fructose, levoglucosan). The most thermodynamically stable starch-Eu complex has metal-to-ligand ratio of 1 : 5 while the least stable one is Eu-levoglucosan complex. Lanthanide-starch complexes also prove to be most effective electron donors out of studied compounds with their donor capacity decreasing as the number of starch mononers decrease. Eu and Tb complexes with invidual compounds (glucose, fructose and levoglucosan) have low donoracceptor activity as their boundary orbitals lie much lower than Fermi level. Starch and glucose may potentially facilitate electron transfers between ?-electrons of carbohydrate ligand and excited orbitals of lanthanide ions.
1. Whistler R. L., BeMiller J. N. Industrial Gums, Polysaccharides and Their Derivatives. N.Y. : Academic Press, 1993. 219 p.
2. Peng J., Gao W., Kumar Gupta B., Liu Z., Romero-Aburto R., Ge L., Song L., Alemany L. B., Zhan X., Gao G., Vithayathil S. A., Kaipparettu B. A., Marti A. A., Hayashi T., Zhu J.-J., Ajayan P. M. Graphene quantum dots derived from carbon fi bers // Nano Letters. Vol. 12, iss. 2. P. 844–849.
3. Zhang M., Bai L., Shang W., Xie W., Ma H., Fu Y., Fang D., Sun H., Fan L., Han M., Liu C., Yang S. Facile synthesis of water-soluble, highly fluorescent graphene quantum dots as a robust biological label for stem cells // J. of Mater. Chem. 2012. Vol. 22. P. 7461–7467.
4. Lu J., Yeo P. S., Gan C. K., Wu P. Transforming C60 Molecules into Graphene Quantum Dots // Nature Nanotechnology. 2011. Vol. 6. P. 247–252.
5. Ju S. Y., Kopcha W. P., Papadimitrakopoulos F. Brightly Fluorescent Single-walled Carbon Nanotubes via an Oxygen-excluding Surfactant Organization // Science. 2009. Vol. 323 (5919). P. 1319–1323.
6. Stewart J. J. P. Stewart Computational Chemistry MOPAC2016 version 12.301M. URL: http://OpenMOPAC.net (дата обращения: 02.11.2017).
7. Dutra J. D. D., Filho M. A. M., Rocha G. B., Freire R. O., Simas A. M., Stewart J. J. P. Sparkle/PM7 Parameters for all Lanthanide // J. Chem. Theory Comput. 2013. № 9 (8). P. 3333–3341.
8. Джарлагасова Д. Н., Захарова Т. В., Пожаров М. В. Квантово-химическое изучение возможных структур в системе альгиновая кислота-хлорид европия (III) // Изв. Сарат. ун-та. Нов. сер. Сер. Химия. Биология. Экология. 2017. Т. 17, вып. 1. С. 19–23.
9. Schwenker R., Beck L. Study of the pyrolitic decomposition of cellulose by gas chromatography // J. Polymer Sci. C1. 1963. Vol. 2. P. 331–340.
10. Ciesielski W., Tomasik P. Starch radicals. Part I. Thermolysis of plain starch // Carbohydr. Polym. 1996. Vol. 31, iss. 4. P. 205–210.
11. Dolg M., Stoll H., Preuss H. A Combination of Quasirelativistic Pseudopotential and Ligand Field Calculations for Lanthanoid Compounds // Theor. Chim. Acta. 1993. Vol. 85. P. 411–450.
12. Dolg M., Stoll H., Savin A., Preuss H. Energy-adjusted Pseudopotentials for the Rare Earth Elements // Theor. Chim. Acta. 1989. Vol. 75. P. 173–194.
13. Niese F. The ORCA Program System // Wiley Intern. Rev. : Comput. Molec. Sci. 2012. Vol. 2, iss. 5. P. 75–78.
14. Binnemans K. Interpretation of Europium (III) Spectra // Coord. Chem. Rev. 2015. Vol. 295. P. 1–45.