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Lipidporphyrinatoiron(II) complexes are tetrakis(o-substituted)phenylporphinatoiron(II) derivatives which can be easily dispersed in water by molecular assembling. The most remarkable aspect of lipidporphyrinatoiron(II) assemblies is their reversible binding of dioxygen under physiological conditions (in aqueous media, pH 7.3, 37 °C) like hemoglobin and myoglobin. In these structures the O₂-binding properties are largely influenced by the molecular environment around the coordination site. Tetrakis(o-pivalamido)phenylporphinatoiron(II) with a covalently linked axial imidazole (lipidporphyrinatoiron(II), 1) is incorporated into recombinant human serum albumin (rHSA), providing a totally synthetic O₂-carrying hemoprotein (rHSA–1). Electrospray ionization mass spectrometry revealed the molecular mass of this non-covalent albumin–porphyrin hybrid. The O₂ rebinding after laser flash photolysis represented a three-phase decay, suggesting that each porphyrin is embedded into different cavities in the albumin structure. On the other hand, amphiphilic lipidporphyrinatoiron(II) with four alkylphosphocholine chains (2) is self-organized in aqueous solution to produce bimolecular fibers with a uniform thickness of 10 nm. This fiber also gave a stable O₂ adduct, and the O₂ rebinding after laser flash irradiation showed monophasic kinetics. Up to 20 vol% of methanol, which is a critical concentration for fiber formation, the morphology was gradually dissociated into spherical micelles, and the stability of the dioxygenated species suddenly decreased to 10% of that of the fibers.

Several recent studies of phthalocyanines and porphyrins as materials in emerging technologies are reviewed here. Emphasis is placed on the use of these materials as components in building materials where the symmetry, optical and electrical properties of the molecule are important. Aggregates or polymers of these molecules have been known for some time to possess interesting electrical conductivities, and more recently interesting optical properties. Their optical properties as isolated species in condensed phases have also recently become interesting, and their ability to form new hybrid materials, by mixing or by thin film deposition, with other molecules with different electron affinities and ionization potentials, now appears to be extremely attractive. Device technologies in which we can anticipate these molecules appearing in the near future include organic light-emitting diodes, organic field effect transisitors, organic photovoltaics, optical limiters and optically based chemical sensors.

We report herein the synthesis and characterization of novel cobalt chlathrochelate-zinc porphyrin assemblies. X-ray data and electrochemical studies support the formation and maintenance of these structures both in solid and solution states. Light induced charge accumulation at the cobalt center was realized in the presence of a sacrificial electron donor. The photogenerated Co(I) species was stable in the ms time scale in aqueous medium.