Dependence of the dimension of the associates of water-soluble tris-malonate of light fullerene -C 60 [= C(COOH) 2 ] 3 in water solutions at 25 • C Investigation of the concentration dependence of the size and type C 60 [=C(COOH) 2 ] 3 aggregation in aqueous solutions at 25 • C was accomplished with the help of a dynamic light scattering method. It was determined that three types of aggregates are realized in the solutions. The average number of C 60 [=C(COOH) 2 ] 3 molecules in smaller aggregates and all types of aggregates were calculated. One can see that over the whole concentration range, from 0.01 to 10 g/dm 3 , aqueous solutions of C 60 [=C(COOH) 2 ] 3 are characterized by sub-micro-heterogeneous behavior (because second-type aggregates with the linear dimensions -hundreds of nm are formed in all solutions). Additionally, the most concentrated solution (C = 10 g/dm 3 ) is characterized by micro-heterogeneous or colloid behavior (because third-type aggregates with the linear dimensions on the order of µm -are formed). In order to describe or explain such behavior, a stepwise aggregation model was invoked.Keywords: tris-malonate of light fullerene, method of the dynamic light scattering.

Cryometry investigations of the C 60 (OH) 24±2 -H 2 O and C 70 [=C(COOH) 2 ] 3 -H 2 O binary systems were conducted over the 0.1 -10 g concentration range of fullerenols per 1 dm 3 of solutions. The decreases of the temperatures at the onset of H 2 O -ice crystallization were determined. Excess functions of aqueous solutions -water and fullerenols (trismalonates) activities and activity coefficients and excess Gibbs energy of the solutions were calculated. All solutions demonstrated huge deviations from those of ideal solutions. The last fact, to our opinion, is caused by a very specific -hierarchical type of association of fullerenols (trismalonates) solution components, which was proved by the results of visible light scattering analysis.

The paper presents some data on physico-chemical study of the C 70 -carboxyfullerene water solutions. The data on temperature dependence of solubility in water, concentration dependence of density, specific conductivity, molar conductivity, dissociation constant, and dynamic light scattering are presented and characterized; composition of equilibrium solid phase in binary C 70 -carboxyfullerene + water system is determined.

The investigation of concentration dependence of mass transport properties (diffusion coefficients and viscosity) of the water soluble light fullerene tris-malonate -C 60 [=C(COOH) 2 ] 3 in aqueous solutions was provided. Activation energies for the diffusion and viscous current were calculated.