Two dimensional pi conjugated metal porphyrin covalent organic frameworkswere produced in aqueous solution on an iodine-modified Au(111) surface by onsite azomethine coupling of Fe(III) 5,10,15,20 tetrakis(4 aminophenyl)porphyrin(FeTAPP) with terephthal dicarboxaldehyde and investigated in detail usingin-situ scanning tunneling microscopy. Mixed covalent organic porphyrinframeworks consisting of FeTAPP and metal-free TAPP (H2TAPP) were preparedthrough simultaneous adsorption in a mixed solution as well as partialreplacement of FeTAPP by H2TAPP in an as prepared metal porphyrin framework. Inthe mixed framework, the relative distribution of FeTAPP to H2TAPP was notrandom and revealed a preference for homo-connection rather thanheteroconnection. The construction of substrate-supported, pi conjugatedcovalent frameworks from multiple building blocks, including metal centers,will be of significant utility in the design of functional molecularnanoarchitectures.
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