Record Multiphoton Absorption Cross‐Sections by Dendrimer Organometalation1. Issue 7 (21st January 2016)

• Record Type: Journal Article
• Authors: Simpson, Peter V.; Watson, Laurance A.; Barlow, Adam; Wang, Genmiao; Cifuentes, Marie P.; Humphrey, Mark G.
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 7(2016)
• Page Start: 2387
• Page End: 2391
• Publication Date: 2016-01-21
• Subjects: dendrimers -- nonlinear optics -- optically active materials -- photonics -- ruthenium; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201509223
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Large increases in molecular two‐photon absorption, the onset of measurable molecular three‐photon absorption, and record molecular four‐photon absorption in organic π‐delocalizable frameworks are achieved by incorporation of bis(diphosphine)ruthenium units with alkynyl linkages. The resultant ruthenium alkynyl‐containing dendrimers exhibit strong multiphoton absorption activity through the biological and telecommunications windows in the near‐infrared region. The ligated ruthenium units significantly enhance solubility and introduce fully reversible redox switchability to the optical properties. Increasing the ruthenium content leads to substantial increases in multiphoton absorption properties without any loss of optical transparency. This significant improvement in multiphoton absorption performance by incorporation of the organometallic units into the organic π‐framework is maintained when the relevant parameters are scaled by molecular weights or number of delocalizable π‐electrons. The four‐photon absorption cross‐section of the most metal‐rich dendrimer is an order of magnitude greater than the previous record value. Abstract : A significant increase in two‐photon absorption (2PA) cross‐section σ 2 (blue) at biologically important wavelengths, and the appearance of large 3PA (red) and record 4PA (green) cross‐sections in the telecommunications region, is achieved by incorporation of ruthenium alkynyl units into a dendritic structure. Spectra are scaled along x axis as indicated.