The role of nanodiamonds in the reaction of photochemical transformation of tryptophan in the presence of halogen hydrocarbons has been studied. The photochemical transformation of free tryptophan in a suspension with diamond nanoparticles and in a hybrid complex with them when exposed to UV radiation in the presence of chloroform is investigated. Data from stationary and time-resolved spectroscopic studies show the presence of non-radiative transfer of electron excitation energy between tryptophan molecules and its photodestruction products for the case of a covalent complex with a nanodiamond. It is shown that in the presence of energy transfer, an increase in the intensity of integral fluorescence occurs in the range of ~ 450 nm. Thus, a covalent tryptophan complex with a nanodiamond can serve as a fluorescent marker for the presence of chloroform in solution.

Meso-tetra (4-carboxyphenyl) porphyrin complexes with nano-sized diamonds were studied spectroscopically. The polarization characteristics of their steady-state fluorescence indicate the formation of a covalently bound complex between porphyrin molecules and diamond nanoparticles. The hydrodynamic volumes of the studied complexes were estimated on the basis of data on steady-state fluorescence anisotropy. Measurements have shown that the photophysical properties of porphyrin do not change significantly when an organo-inorganic hybrid complex with nanodiamonds is formed. The studied complexes can be promising in the field of biomedical research, in particular, for diagnostic purposes and for the development of new generation photosensitizers for practical medicine.