Synthesis, Spectral, Redox, and Sensing Studies of β-Dicyanovinyl- Appended Corroles and Their Metal Complexes

A new family of fi-dicyanovinyl (DCV)-appended corroles represented as MTPC(MN) (where M = 3H, Cu, Ag, and Co(PPh3) and MN = malononitrile and TPC = 5,10,15-triphenylcorrole) were synthesized starting from the free base mono fi-formyl corrole, H3TPC(CHO), and characterized along with their respective MTPC(CHO) and MTPC complexes as to their spectroscopic and electrochemical properties in nonaqueous media. Comparisons between the two series of corroles demonstrate a pronounced substituent effect of the fi-DCV group on the physicochemical properties making the MTPC(MN) derivatives substantially easier to reduce and more difficult to oxidize than the formyl or unsubstituted corroles. In addition, the colorimetric and spectral detection of 11 different anions (X) in the form of tetrabutylammonium salts (TBAX, X = PF6-, OAc-, H2PO4-, CN-, HSO4-, NO3-, ClO4-, F-, Cl-, Br-, and I-) were also investigated in nonaqueous media. Of the investigated anions, only CN- was found to induce changes in the UV-vis and 1H NMR spectra of the fi- DCV metallocorroles. This data revealed that CuTPC(MN) and AgTPC(MN) act as chemodosimeters for selective cyanide ion detection via a nucleophilic attack at the vinylic carbon of the DCV substituent, while (PPh3)CoTPC(MN) acts as a chemosensor for cyanide ion sensing via axial coordination to the cobalt metal center. A low-limit detection of cyanide ions was observed at 1.69 ppm for CuTPC(MN) and 1.17 ppm for AgTPC(MN) in toluene.

Automated summary

A new family of fi-dicyanovinyl (DCV)-appended corroles, MTPC(MN), were synthesized and their spectroscopic and electrochemical properties were investigated. The results showed that the fi-DCV group had a pronounced substituent effect on the physicochemical properties, making the MTPC(MN) derivatives easier to reduce and more difficult to oxidize. The DCV metallocorroles CuTPC(MN) and AgTPC(MN) acted as chemodosimeters for selective cyanide ion detection, while (PPh3)CoTPC(MN) acted as a chemosensor for cyanide ion sensing.