Organometallic Complexes for Nonlinear Optics, 47 - Synthesis and Cubic Optical Nonlinearity of a Stilbenylethynylruthenium Dendrimer

The synthesis of the 1st generation dendrimer 1,3,5‐{trans‐[Ru(C≡C‐3,5‐(trans‐[Ru(C≡CPh)(dppe)2(C≡CC6H4‐4‐(E)‐CHCH)])2C6H3)(dppe)2(C≡CC6H4‐4‐(E)‐CHCH)]}3C6H3 proceeds by a novel route that features Emmons‐Horner‐Wadsworth coupling of 1,3,5‐C6H3(CH2PO(OEt)2)3 with trans‐[Ru(C≡CC6H4‐4‐CHO)Cl(dppe)2] and 1‐I‐C6H3‐3,5‐(CH2PO(OEt)2)2 with trans‐[Ru(C≡CPh)(C≡CC6H4‐4‐CHO)(dppe)2] as key steps. The stilbenylethynylruthenium dendrimer is much more soluble than its ethynylated analog 1,3,5‐{trans‐[Ru(C≡C‐3,5‐(trans‐[Ru(C≡CPh)(dppe)2(C≡CC6H4‐4‐C≡C)])2C6H3)(dppe)2(C≡CC6H4‐4‐C≡C)]}3C6H3 and, in contrast to the ethynylated analog, is a two‐photon absorber at telecommunications wavelengths. The 1st generation stilbenylethynylruthenium dendrimer shown here is prepared by a synthetic route that exploits Emmons–Horner–Wadsworth coupling of metal ethynyl‐functionalized benzaldehyde. Its molecular weight‐scaled refractive nonlinearity is significantly larger than that of its zero‐generation analog, an NLO dendritic effect. In contrast to its all‐ethynyl‐linked analog, it is a nonlinear absorber at telecommunications wavelengths.