Spectral and photophysical characteristics of borofluoride complex of alkylated dipyrromethene (Bodipy) are determined by means of absorption and fluorescence electron spectroscopy in various organic solvents. Dependences of the spectral and photophysical characteristics of Bodipy solutions vs. the physico-chemical parameters of solvents are obtained by linear regression analysis and the contribution from each parameter to the property under study is determined. It is established that the negative solvatochromic effect is intrinsic for Bodipy. It is concluded that specific interactions contribute substantially to the properties of the chromophore, which are determined by the electron donor properties of the solvent.

We report the synthesis, purification and identification of a new derived class of BODIPY - of naphtho-fused BODIPY analogue, 8-(3,5-dimethylphenyl)-4,4-difluoro-4-bora-3a,4a-diaza-dinapht-[1,2b][1,2c]-s-indacene. A detailed method for obtaining the compound was given. The structure was confirmed by nuclear magnetic resonance spectroscopy, infrared spectroscopy and mass spectrometry. Electronic absorption and fluorescence spectra were obtained in solvents of different nature. The effect of solvent nature on the positions of absorption and fluorescence peaks and Stokes shift has been studied. It has been shown that the nature of the solvent has a significant effect on the fluorescence intensity and does not significantly effect the position of the absorption peaks. The photophysical characteristics of the compound were compared with known alkylated analogues. It is shown that the expansion of the electronic system leads to a bathochromic shift in the electronic absorption and fluorescence spectra. Quantum-chemical calculations of the electronic absorption and fluorescence spectra were carried out using the TDDFT (time dependent density functional theory) method. The influence of the extended π-electron system on the position and character of the absorption and fluorescence spectra was studied. It is shown that the presence of naphthalene fragments conjugated with the BODIPY core leads to a bathochromic shift of the absorption and fluorescence bands, as well as a partial change in the character of the spectra. The energy levels and electronic structure of the FMOs with the TDDFT method were calculated. The calculated data are in good agreement with the results obtained by experimental methods. The results obtained, in turn, are consistent with the results obtained earlier by our scientific group. Compounds that possess such properties are especially important and could be used in such practical applications as photovoltaics, photodynamic therapy of oncological diseases and as agents for visualization of biomolecules.

Using fluorescence and electronic spectroscopy the interaction of boron-dipyrromethene complex (BODIPY) with bovine serum albumin (BSA) and its bilirubin macromolecular complex (BR·BSA) in aqueous solution was investigated. The interaction of BODIPY is carried out by the static quenching of protein fluorescence and is predominantly hydrophobic and electrostatic in nature. The values of the binding constants were (61.2 ± 2.8) · 10³ and (6.51 ± 0.3) · 10³ M⁻¹. The interaction of BODIPY with proteins leads to the observed hypso- and bathochromic shift in BODIPY absorption band. Forster resonance energy transfer theory allowed of determing the donor-ligand distance, which were 2.88 and 2.46 nm for BSA and BR·BSA, respectively. Using synchronous fluorescence spectroscopy it was possible to reveal features of BODIPY influence on conformational changes in protein molecules. It was established that BODIPY more effectively interacts with BSA compared to BR·BSA.

The design of cargo carriers with high biocompatibility, unique morphological characteristics, and capability of strong bonding of fluorescent dye is highly important for the development of a platform for smart imaging and diagnostics. In this paper, BODIPY-doped silica nanoparticles were prepared through a “one-pot” soft-template method using a sol-gel process. Several sol-gel precursors have been used in sol-gel synthesis in the presence of soft-template to obtain the silica-based materials with the most appropriate morphological features for the immobilization of BODIPY molecules. Obtained silica particles have been shown to be non-cytotoxic and can be effectively internalized into the cervical cancer cell line (HeLa). The described method of synthesis allows us to obtain silica-based carriers with an immobilized fluorescent dye that provide the possibility for real-time imaging and detection of these carriers.