Design and synthesis of new nonlinear optical chromophores incorporating diphenylphosphino groups and their incorporation into electroactive dendrimers

The replacement of first row elements by second row elements (e.g. S for O) in electron donating groups in conjugated organic materials has been shown to produce an enhancement of the nonlinear response. Amino functionalities have been utilized as strong donors in the design of molecules for both second and third order NLO applications. In the present work N (Nitrogen) has been replaced by P (Phosphorus) in various chromophore functionalities. A series of bis-(diphenylphosphino)diphenyl polyenes with up to five double bonds, a bis-(diphenylphosphino)-PPV dimer, and a diphenylphosphino DANS equivalent have been synthesized. In addition, the first generations (G0) of two types of dendrimers were made by a divergent approach. The first type is a series of three arm dendrimers with stilbene type units. The second type is a series of three arm dendrimers with PPV type units.; These new molecules were compared to the N equivalents in several characteristics such as absorption, organic light emitting diodes (OLED), nonlinear optical properties, two-photon absorption, and reverse saturable absorption.; It was found out that diphenylphosphino substituents behave as weak electron-withdrawing groups despite the lone pair of electrons. Compared to N, the lone pair of electrons of P participates weakly in the conjugation of π-systems, which results in a blue shift in λ_max.