TRANS-SUBSTITUTED PORPHYRIN BUILDING-BLOCKS BEARING IODO AND ETHYNYL GROUPS FOR APPLICATIONS IN BIOORGANIC AND MATERIALS CHEMISTRY

The modular synthesis of linear or cyclic multiporphyrin arrays relies on the availability of trans-substituted porphyrin building blocks wi th high solubility in organic solvents. Eleven porphyrin building bloc ks were synthesized bearing iodo, ethynyl, and 2-(trimethylsilyl)ethyn yl groups at the 4-, 3-, or 3,5-positions of two mesa-aryl units. and mesityl groups at the other two mesa-positions. The synthesis involves condensation of 5-mesityldiprromethane with one or two aryl aldehydes . Combinations of functional groups include di-iodo, tetra-iodo, bis [ (2-(trimethylsilyl)ethynyl], iodo and 2-(trimethylsilyl)ethynyl, and e thynyl and 2-(trimethylsilyl)ethynyl. In addition, a porphyrin bearing one 4-iodophenyl group and one 3,5-bis(boron-dipyrrin)phenyl group wa s synthesized for applications in molecular photonic devices. The iodo and ethynyl groups are ideally-suited for Pd-mediated coupling reacti ons, allowing the porphyrin building blocks to be joined in the system atic construction of soluble multiporphyrin arrays. (C) 1998 Elsevier Science Ltd. All rights reserved.