Physico-chemical properties of β-diketone phosphorus-containing dendrimers

Protolytic, absorbance and fluorescence properties of β-diketone phosphorus-containing dendrimers based on cyclotriphosphazene core were studied. Dendrimer solutions in acetone are characterized by intense absorbance band at ≈ 340 nm (ε340≈ 8.5·104L/mol·сm) and fluorescence band with maximum at 440 nm. Position of these maxima does not change in various solvents, unlike the bands of monomer β-diketone. It was found that dendrimer aggregation is accompanied by appearance of a second absorbance band ε400≈ 4.5·103L/mol·сm, by red shift of emission spectra ∆λ ≈ 10 nm and also by decrease in surface tension of acetone solution. Ability of dendrimer aggregates to solubilize organic substrates was observed with the fluorescent indicator acridine