Physico-chemical properties of C 70 -L-threonine bisadduct (C 70 (C 4 H 9 NO 2 ) 2 ) aqueous solutions Evgeny B. Serebryakov a , Dmitry N. Zakusilo a , Konstantin N. Semenov a, ⁎, Nikolay A. Charykov b , Aleksandr V. Akentiev a , Boris A. Noskov a , Andrey V. Petrov a , Nikita E. Podolsky a , Anton S. Mazur a , Larisa V. Dul'neva c , Igor V. Murin a a Institute of Chemistry, Saint-Petersburg State University, Saint-Petersburg 198504, Universitetskii pr. 26, Russia b Saint-Petersburg State Technological Institute (Technical University), Saint-Petersburg 190013, Moskovskii pr. 26, Russia c Pavlov First Saint Petersburg State Medical University, Saint-Petersburg 197022, L'va Tolstogo str. 6-8, Russia abstract article info Article history: Received 6 May 2018 Received in revised form 15 December 2018 Accepted 3 February 2019 Available online 06 February 2019 The paper is devoted to the physico-chemical investigation of the C 70 -Thr aqueous solutions. In the framework of our study, we measured densities (ρ), viscosities (η), refraction indexes (n D ) and surface tension (γ) in a wide range of concentrations. Experimental data on size distribution and ζ-potentials of the C 70 -Thr associates in aque- ous solutions were obtained in the concentration range C = 0.001–5 g·dm −3 at 298.15 K. Using experimental data on the decreasing of the ice crystallization temperature in the C 70 -Thr–water binary system, the excess ther- modynamic functions were calculated. Additionally, the structural and dynamic characteristics of the C 70 -Thr– water binary system were obtained on the basis of molecular dynamics method. © 2019 Elsevier B.V. All rights reserved. Keywords: Fullerene derivatives Physico-chemical properties Density Viscosity Refraction index Molecular dynamics Excess thermodynamic functions Surface tension 1. Introduction Fullerene derivatives and, in particular, the light fullerene deriva- tives with amino acids are very perspective compounds due to the pos- sibilities of practical application in biochemistry and medicine [1–10]. For example, they can be used as lead compounds of anticancer, neuro- protective, antiviral drugs and possess antimicrobial and antioxidant ac- tivities [11–17]. At the same time, for realization of biomedical potential of these compounds, it is important to carry out the investigation of physico-chemical properties and find the correlation between the struc- ture of fullerene derivatives and their properties in solid state and in solutions. Let us briefly summarize the literature data devoted to physico- chemical investigation of fullerene derivatives with amino acids. Leon et al. studied the ability of the C 60 fullerene to interact with amino acids and performed calculations using DFT-method under B3LYP/3-21G approach [18]. The authors determined that obtained complexes are stable and the highest dissociation energies correspond to fullerene adducts with leucine, arginine, tryptophan and glutamine. Dolinina et al. studied the stereoselectivity of formation of hybrid amino acid derivatives of C 60 [19]. Using DFT method with B3LYP func- tional (6-31G basis), the authors calculated the energies of the amino acids addition to the fullerene core. The authors determined that the most stable structures of the fullerene derivatives should consist of two amino acids residues in para-position of the C 60 hexagon. Addition- ally, the authors calculated three-dimensional structures of six hybrid 1,4-isomers of C 60 and evaluated the contact surface with solvent mole- cules. Performed calculations revealed that the presence of amino acid residues decreases the surface of contact of the fullerene core with water but, at the same time, hydrophobic properties of C 60 promote the process of cluster formation. Luzhkov et al. calculated the absolute values of pK a of the dissociat- ing groups of the L-Ala-C 60 H in water [20]. Using quantum chemical simulation, the authors determined the base strength of L-Ala-C 60 H de- rivative in the gaseous phase, energies of solvation, as well as stability of the L-Ala-C 60 H isomers and equilibrium conformations in neutral and anionic states. Danilenko et al. obtained concentration dependences of heat capac- ities of aqueous solutions of the fullerene derivatives with amino acids and peptides [21]. It was determined that heat capacities of C 60 fullerene derivatives with L-arginine, DL-alanyl-DL-alanine and glycyl-L-valine are Journal of Molecular Liquids 279 (2019) 687–699 ⁎ Corresponding author. E-mail address: k.semenov@spbu.ru (K.N. Semenov). https://doi.org/10.1016/j.molliq.2019.02.013 0167-7322/© 2019 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq