Computational study of supramolecular bis-porphyrin 'molecular tweezers'

A computational study of a series of space sepd. bis-porphyrin \"mol. tweezers\" using semiempirical (AM1) and DFT (B3LYP and PBE1PBE) methods has been carried out. It was found that polynorbornane bis-porphyrin systems are significantly less rigid than previously thought. The variation of the metal-metal sepn. distance between the two porphyrin centers does not cause a significant energy change thus enabling these mols. to easily adjust to the optimal coordination distance required for complexation by various bidentate 4-pyridyl ligands inside the cavity of these \"tweezers\". [on SciFinder (R)]