Optical, third order non-linear optical and electrochemical properties of dipolar, centrosymmetric and C2v organoimido polyoxometalate derivatives. Issue 20 (14th May 2021)

• Record Type: Journal Article
• Authors: Al-Yasari, Ahmed; El Moll, Hani; Purdy, Ryan; Vincent, Kevin B.; Spence, Philip; Malval, Jean-Pierre; Fielden, John
• Is Part Of: Physical chemistry chemical physics. Volume 23:Issue 20(2021)
• Page Start: 11807
• Page End: 11817
• Publication Date: 2021-05-14
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d0cp06610a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Arylimido Lindqvist polyoxometalates (POMs) are shown to be effective acceptors for two-photon absorption. In bis-POM systems the geometry–centrosymmetric or V-shaped–strongly influences optical and non-linear optical properties. Abstract : A family comprising seven arylimido-polyoxometalate (POM) hybrid chromophores (three of which are new), with linear dipolar, C 2v and linear centrosymmetric geometries have been synthesised and studied by electronic absorption spectroscopy, electrochemistry, Z-scans (two photon absorption, TPA) and computation (DFT/TD-DFT). These reveal that POM acceptor units are an effective basis for TPA materials: the centrosymmetric bis-POM chromophores produce significant cross sections ( δ up to 82 GM) from a single aryl bridge, a similar performance to larger dipolar π-systems combining carbazole or diphenylamino donors with the imido-POM acceptor. DFT/TD-DFT calculations indicate strong communication between POM and organic components is responsible for the linear and non-linear optical behaviour of these compounds, while electrochemical measurements reveal class II mixed valence behaviour resulting from an interplay of through-bond and through-space effects.