title: Evaluation of the nonlinear optical properties for an expanded porphyrin Hückel-Möbius aromaticity switch.
abstract: The conformational flexibility of the expanded porphyrins allows them to achieve different topologies with distinct aromaticities and nonlinear optical properties (NLOP). For instance, it is possible to switch between Möbius and Hückel topologies applying only small changes in the external conditions or in the structure of the ring. In this work, we evaluate the electronic and vibrational contributions to static and dynamic NLOP of the Hückel and Möbius conformers of A,D-di-p-benzi[28]hexaphyrin(1.1.1.1.1.1) synthesized by Latos-Grażyński and co-workers [Angew. Chem., Int. Ed. 46, 7869 (2007)]. Calculations are performed at the HF, M052X, and CAM-B3LYP levels using the 6-31G, 6-311G(d), and 6-31+G(d) basis sets. Our results conclude that M052X∕6-31G and CAM-B3LYP/6-31G methods provide a correct qualitative description of the electronic and vibrational contributions for the NLOP of expanded porphyrins. The studied systems show high NLOP with large differences between the Möbius and Hückel conformations (around 1 × 10(6) a.u. for γ). The obtained results indicate that the expanded porphyrins are promising systems to manufacture Hückel-to-Möbius topological switches.
authors.affiliation: Departament de Química Biològica i Modelització Molecular, Institut de Química Avançada de Catalunya (IQAC-CSIC), c∕ Jordi Girona 18, E-08034 Barcelona, Spain. miqueltorrentsucarrat@gmail.com
authors.forename: Miquel
authors.initials: M
authors.lastname: Torrent-Sucarrat
authors.forename: Josep M
authors.initials: JM
authors.lastname: Anglada
authors.forename: Josep M
authors.initials: JM
authors.lastname: Luis
mesh_terms: D055620:Optical Phenomena; D011166:Porphyrins / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D011166:Porphyrins