Metallophthalocyanines are well known nonlinear optical materials which have found application as optical limiters.  Surprisingly, metallotetraazaporphyrins, which are isostructural except for the four peripheral benzo groups, do not show sequential two-photon absorption.  In an attempt to understand the structural features necessary for nonlinear optical behavior, we have synthesized four new macrocycles � tetraazapor-phyrins bearing between one and three peripheral benzo groups.  These four compounds, which form a homologous series bridging phthalocyanines and tetraazaporphyrins, were prepared by 1) mixed condensations of phthalonitrile and maleinitrile precursors and 2) ring expansion of subphthalocyanines and subtrizaporphyrins.  Either synthetic method required careful chromatographic separation of the desired materials.  The four new macrocycles have been characterized by UV-visible and NMR spectroscopy and mass spectrometry.  Experimental UV-visible spectra were also compared to singlet and triplet spectra calculated using time-dependent density functional theory.

Synthesis and characterization of mono, di and tribenzo tetraazaporphyrins: Study of structural features needed for effective optical limiting

243rd National Meeting (2012)

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