Syntheses and Optical Properties of Azo‐Functionalized Ruthenium Alkynyl Complexes

Abstract

The syntheses of trans‐[Ru(C≡C‐1‐C6H4‐4‐N=N‐1‐C6H4‐4‐C≡C‐1‐C6H4‐4‐NO2)Cl(L2)2] (L2=dppm (Ru1), dppe) (Ru2)), trans‐[Ru(C≡C‐1‐C6H4‐4‐N=N‐1‐C6H4‐4‐(E)‐CH=CH‐1‐C6H4‐4‐NO2)Cl(dppe)2] (Ru3), and trans‐[Ru(C≡C‐1‐C6H4‐4‐(E)‐CH=CH‐1‐C6H2‐2,6‐Et2‐4‐N=N‐1‐C6H4‐4‐NO2)Cl(dppe)2] (Ru4) are reported, together with those of precursor alkynes. Their electrochemical properties were assessed by cyclic voltammetry (CV), linear optical and quadratic nonlinear optical (NLO) properties assayed by UV/Vis‐NIR spectroscopy and hyper‐Rayleigh scattering studies at 1064 nm, respectively, and their linear optical properties in the formally RuIII state examined by UV/Vis‐NIR spectroelectrochemistry. These data were compared to those of analogues with E‐ene and yne linkages in place of the azo groups. Computational studies using time‐dependent density functional theory were undertaken on model compounds (Ru2′–Ru4′) to rationalize the optical behaviour of the experimental complexes.

Computational studies of the nonlinear optical properties of organometallic complexes

“…In recent years, with the rapid growth of computer power as well as efficient algorithms, NLO calculations have been performed using ab initio methods coupled with derivative methods (discussed later), in particular density functional theory (DFT) [81][82][83][84][85][86]. A detailed discussion of quantum chemical NLO calculations with reference to the metal alkynyl complexes is given in a later section.…”