Synthesis and Spectroscopic Characterization of Zinc Tetra(3,4-pyridine)Porphyrazine Entrapped within the Supercages of Y-Zeolite.
In this work, the generation of Y-zeolite-entrapped zinc tetra(3,4-pyridine)porphyrazine (ZnPz-Z) at several loading levels is reported. The ZnPz-Z samples were obtained using the template synthesis method involving condensation of 3,4-dicyanopyridine (DCP) around Zn(2+) cations which had been ion-exchanged into the Y-zeolite supercages (Zn(2+)-Z). The integrity of the sample was documented by diffuse reflectance (DR), emission (Em) and resonance Raman (RR) spectroscopic data. The Raman spectrum for the ground-state ZnPz-Z intrazeolitic complex, with the laser excitation at lambda(ex) = 568.2 nm, closely matched that obtained for the free ZnPz porphyrazine, with some bands exhibiting slight frequency shifts of 1-5 cm(-)(1). The DR spectrum of ZnPz-Z exhibited maxima at lambda(max) = 414 and 682 nm, and the emission spectrum of ZnPz-Z revealed fluorescence at lambda(em) = 705 nm, with lambda(ex) = 350.9, 406.7, or 647.1 nm. This emission was 22 nm red shifted with respect to that recorded for the free ZnPz complex in pyridine solution and 24 nm red shifted relative to that acquired for the ZnPz complex adsorbed on the outer surface of the zeolite. All these spectroscopic data suggest that the ZnPz molecules within the zeolite supercages were only slightly distorted. The ZnPz-Z samples contain a small amount of luminescent (lambda(em) = 500 nm) impurities assigned to products of 3,4-dicyanopyridine noncyclic condensation.
Szulbinski
Witold S.
WS
Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881.
Kincaid
James R.
JR