Bis(4,4′‐dimethyl‐2,2′‐bipyridine) ruthenium (II) Complexes Containing 2‐Arylimidazo‐ [4,5‐f] [1,10] phenanthroline: Syntheses,Characterization and Third‐order Nonlinear Optical Properties

Four novel mononuclear ruthenium(II) complexes Ru(dmb)₂L]²⁺ dmb = 4,4′‐dimethyl‐2,2′‐bipyridine, L = imidazo‐4,5‐f]1,10]phenanthroline (IP), 2‐phenylimidazo‐4,5‐f]1,10]phenanthroline (PIP), 2‐(4′‐hydroxyphenyl)imidazo‐4,5‐f] 1,10] phenanthroline (HOP), 2‐(4′‐dimethylaminophenyl) imidazo‐4, 5‐f] 1,10] phenanthroline (DMNP)] were synthesized and characterized by ES‐MS, ¹H NMR, UV‐vis and electrochemistry. The nonlinear optical properties of the ruthenium(II) complexes were investigated by Z‐scan techniques with 12 ns laser pulse at 540 nm, and all of them exhibit both nonlinear optical (NLO) absorption and self‐defocusing effect. The corresponding effective NLO susceptibility |x³| of the complexes is in the range of 2.68 × 10^?12‐4.57 × 10^?12 esu.