Syntheses and Properties of Two-Dimensional Charged Nonlinear Optical Chromophores Incorporating Redox-Switchable cis-Tetraammineruthenium(II) Centers

• Published in: Journal of the American Chemical Society 2005-04, Vol.127 (13), p.4845-4859
• Main Authors: Coe, Benjamin J, Harris, James A, Jones, Lathe A, Brunschwig, Bruce S, Song, Kai, Clays, Koen, Garín, Javier, Orduna, Jesús, Coles, Simon J, Hursthouse, Michael B
• Format: Article
• Language: English
• Subjects: Chemistry; Coordination compounds; Exact sciences and technology; Inorganic chemistry and origins of life; Preparations and properties
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja0424124

In this article, we describe a series of new complex salts in which electron-donating cis-{RuII(NH3)4}2+ centers are connected to two electron-accepting N-methyl/aryl-pyridinium groups. These V-shaped complexes contain either monodentate 4,4‘-bipyridyl-derived ligands or related chelates based on 2,2‘:4,4‘ ‘:4‘,4‘ ‘‘-quaterpyridyl and have been characterized by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. Molecular quadratic nonlinear optical (NLO) responses β have been determined by using hyper-Rayleigh scattering at 800 nm and also via Stark (electroabsorption) spectroscopic studies on the intense, visible d → π* metal-to-ligand charge-transfer bands. These experiments reveal that these dipolar pseudo-C 2 v chromophores exhibit two substantial components of the β tensor, β zzz and β zyy , with the difference between them being most marked for the nonchelated systems. Time-dependent density-functional theory and finite field calculations serve to further illuminate the electronic structures and associated linear and NLO properties of the new chromophoric salts.