Synthesis, Characterization and Calculations of Linear and Nonlinear Optical Properties of Acrylonitrile Substituted Spirocyclotriphosphazene Derivatives.

There methoxy-substituted acrylonitrile compounds (2a, 2b and 2c) were synthesized using method described in the literature. Compounds 3a, 3b and 3c were obtained by using the microwave demethylation method for the first time, then they were reacted with 2,2-dichloro-4,4,6,6-bis[spiro(2′,2″-dioxy-1′,1″-biphenylyl)]-cyclotriphosphazene (DPP) to reach final products 4a, 4b and 4c. The structures of the substituted compounds were determined by elemental analysis, MALDI-TOF, 1H, 1 3 C APT, 3 1 P NMR and FT-IR spectroscopy. In order to investigate the usability potential of the synthesized products 4a, 4b and 4c in optoelectronic devices, we experimentally measured the band gaps and calculated their nonlinear optical properties by Density Functional Theory (DFT) method. Obtained results showed that the introduction of an electronegative substituent (F) or an electropositive substituent (CH 3) to the parent compound 4a has minimal impact on the absorption spectra. However, the fluorine-substituted compound 4b exhibits considerably higher values in terms of dipole moment, averaged polarizability, and first-hyper polarizability when compared to compounds 4a and 4c. Calculated values of dipole moment, averaged polarizability, first-hyper polarizability, electronegativity and global hardness of the fluorine-substituted compound 4b were found to be 6.281 (debye), −393.592 (1.4818 × 10 − 2 5 cm 3) , 899.857 (8.641 × 10 − 3 3 cm5/e.s.u), 4.492 (eV) and 1.922 (eV), respectively. These values were the highest in magnitude in comparison to the associated values of 4a and 4c. Overall results indicated that the influence of introducing an electropositive substituent (CH 3) to the parent compound 4a, resulting in decreased stability and increased reactivity. Conversely, the introduction of an electronegative substituent (F) to 4a leads to opposite effects. Compounds 3a, 3b and 3c were obtained by the microwave demethylation method for the first time, then they were reacted with 2,2-dichloro-4,4,6,6-bis[spiro(2′,2″-dioxy-1′, 1″-biphenylyl)]-cyclotriphosphazene (DPP) to reach final products 4a, 4b and 4c. DFT calculations indicated that the influence of introducing an electropositive substituent (CH3) to the parent compound 4a, resulting in decreased stability and increased reactivity. Conversely, the introduction of an electronegative substituent (F) to 4a leads to opposite effects. [ABSTRACT FROM AUTHOR]