Third-order nonlinear optical properties of ruthenium alkynyl complexes

Abstract

The field of nonlinear optics has expanded rapidly over the last 50 years as these nonlinear optical (NLO) effects are increasing utilised in devices. NLO involves the manipulation of light by as it travels through a material, which has the potential to be used in all optical data processing as well as intensity dependent imaging. These applications demand new materials with large nonlinear optical properties, of which organometallics and metal coordination complexes have a good reputation. Organometallics, especially ruthenium alkynyl complexes permit many different structural alterations which result in linear and nonlinear optical property tuning allowing for precise design of materials, however understanding of the structure-property relationships is imperative for such design. In this work, complexes with a systematically varied structure have been had their third order nonlinear optical properties analysed utilising the Z-scan technique covering a broad wavelength range; the nonlinear absorptive properties being of particular interest. Comparison of these results allows for determination of structural moieties that give high NLO response. Ruthenium alkynyl dendrimers have considerable nonlinear absorptive properties and the second part of this work covers the modification of the core structure to assess its potential for inclusion into larger systems. The level of core substitution (the number of arms branching from the core) and even the core symmetry influences the electronic properties of the molecule and therefore the nonlinear optical properties. The design limitations and synthesis of ruthenium alkynyl complexes with twelve different core substitutions is detailed and the optical and nonlinear optical properties discussed.