The Effect of Electronic Structure on Molecular First Hyperpolarizabilities of Highly Conjugated (Polypyridyl)metal-(Porphinato)zinc(II) Chromophores

Electronic structural modifications of previously reported highly conjugated (polypyridyl)metal-(porphinato)zinc(II) NLO chromophores have been carried out. A primary focus of these modifications probes the role played by porphyrin macrocycle electronic structure in effecting large molecular hyperpolarizabilities. Porphyrin meso-aryl substituents were replaced with electron withdrawing perfluoroalkyl groups, effectively lowering the HOMO and LUMO energies of the porphyrin fragment orbitals by 0.35 eV. Extensive mixing of B, Q, and CT states of the component metal polypyridyl and porphyrinic building blocks coupled with head-to-tail transition dipole alignment of these low energy transitions give rise to substantial molecular hyperpolarizabilities. This work will be placed in the context of ongoing electrooptic experiments and efforts aimed at fabricating new materials from these supermolecular chromophoric species.

Duke Scholars

Author Michael J. Therien Chemistry