Fe−TPP Coordination Network with Metalloporphyrinic Neutral Radicals and Face-to-Face and Edge-to-Face π−π Stacking

Abstract

Compound ([FeTPPbipy]•)n (TPP = meso-tetraphenylporphyrin and bipy = 4,4′-bipyridine) is the first example of a Fe−TPP−bipy coordination network, and it consists of 1D polymers packed through face-to-face and edge-to-face π−π nteractions. The compound has been investigated by means of X-ray diffraction, IR, Mössbauer, UV−visible, and EPR pectroscopies, thermogravimetry, magnetic susceptibility measurements, and quantum-mechanical density functional theory (DFT) and timedependent DFT calculations. The chemical formula for this compound can be confusing because it is compatible with FeII and TPP2− anions. However, the spectroscopic and magnetic properties of this compound are consistent with the presence of low-spin FeIII ions and [FeTPPbipy]• neutral radicals. These radicals are proposed to be formed by the reduction of metalloporphyrin, and the quantum-mechanical calculations are consistent with the fact that the acquired electrons are located on the phenyl groups of TPP.