Theoretical Study on the Second-order Nonlinear Optical Properties of Diaryl Ammonia (Boron)-π-carborane Ternary Compounds

The structures and second order nonlinear optical (NLO) properties of diaryl ammonia (boron)-pi-twelve vertex carborane ternary compounds were studied using density functional theory (DFT) methods. The results show that the conjugated bridge length and diaryl ammonia (boron) of compounds have relatively small influence on their dipole moments. Along with the lengthening of the conjugate bridge and the increases of electronic space scope < R-2 >, polarizability and the first hyperpolarizability increase. From the analysises of electronic spectra and the corresponding molecular orbitals of compounds, it is found that the intramolecular charge transfers within these compounds occur mainly between diaryl ammonia (boron) and the pi-bridge, while carborane has less contribution. In addition, the differences of the electron donating ability between diaryl ammonia and diaryl boron can adjust second-order NLO responses of these compounds.