Optical limiting properties, structure and simplified TD-DFT calculations of scandium tetra-15-crown-5 phthalocyaninates
Aviwe K. May, Poulomi Majumdar, Alexander G. Martynov, Lyudmila A. Lapkina, Sergey I. Troyanov, Yulia G. Gorbunova, А. Yu. Tsivadze, John Mack, Tebello Nyokong
Abstract
The optical limiting properties of crown-ether-substituted scandium(III) phthalocyaninate complexes, bis-tetra-15-crown-5-phthalocyaninates Sc[(15C5) 4 Pc][Formula: see text] (I) and Sc[(15C5) 4 Pc][Formula: see text] (Ia), together with monophthalocyaninate [(15C5) 4 Pc]Sc(OAc) (II) were measured by using the Z-scan technique (532 nm laser and pulse rate of 10 ns). It was revealed that expansion of the [Formula: see text]-system on moving from the monomeric Sc complex II to sandwich compound I and changing the electronic state of the sandwich compound from the anionic Ia species to the neutral radical I improves the optical limiting properties. The Im[[Formula: see text]] values obtained lie in the 10[Formula: see text]–10[Formula: see text] esu range that is consistent with those reported previously for other organic chromophores. The crystal structure of sandwich Sc(III) complex I was elucidated by means of single-crystal X-ray diffraction analysis and was used to guide a series of theoretical calculations. It was demonstrated that the application of simplified time-dependent density functional theory (sTD-DFT) calculations can provide reasonably accurate predictions for compounds of this type when the geometries of the complexes are clearly defined.