Synthesis and characterization of transition metal systems containing phosphino-oligothiophene ligands for nonlinear optical materials
Polythiophenes exhibit interesting third-order nonlinear optical properties but poor solubilities. Incorporating polythiophenes into transition metal complexes should yield readily soluble materials, and the transition metal substituent may alter third-order nonlinear optical properties of the polythiophene. In this paper, we report the synthesis and characterization of 2-diphenylphosphinothianaphthene, A, and its trans-PdCl2L2, B, and cis-PtCl2L2, C, analogues. Additionally 2-diphenylphoshino-5:2‘,5‘:2‘?‘-terthiophene, D, its trans-PdCl2L2 complex, E, both first prepared by Wolf,25 the previously unprepared cis-PtCl2L2 analogue, F, and the oxide of A, G, were prepared and investigated for nonlinear optical (NLO) behavior. No appreciable third-order NLO behavior was observed for A, D, or G. However both E and F exhibited nonlinear refraction, as shown by Z-scan measurements, and nonlinear absorption. The nonlinear absorption was significantly stronger for E, indicating that the metal center has a significant affect on nonlinear absorption. This is the first reported observation of this type of nonlinear behavior in metal?phosphinothiophene systems.
Myrex, R D, Gary M. Gray, Spivey A. G. VanEngen, and Christopher M. Lawson. "Synthesis and Characterization of Transition Metal Systems Containing Phosphino-Oligothiophene Ligands for Nonlinear Optical Materials." Organometallics. 25.21 (2006): 5045-5050. Print.