We investigate dynamic modal operators that can change the model during evaluation. We define the logic $S$ $L$ by extending the basic modal language with the modality, which is a diamond operator that in addition has the ability to invert pairs of related elements in the domain while traversing an edge of the accessibility relation. $S$ $L$ is very expressive: it fails to have the finite and the tree model property. We show that $S$ $L$ is equivalent to a fragment of first-order logic by providing a satisfiability preserving translation. In addition, we provide an equivalence preserving translation from $S$ $L$ to the hybrid logic $H$(:,↓ ). We also define a suitable notion of bisimulation for $S$ $L$ and investigate its expressive power, showing that it lies strictly between the basic modal logic and $H$(:,↓ ). We finally show that its model checking problem is PSpace-complete and its satisfiability problem is undecidable.

The mild (electro)chemical oxidation of pyridin-2-ylthio-meso substituted Ni(II) porphyrins affords C–N fused cationic and dicationic pyridinium-based derivatives. These porphyrins are fully characterized and the molecular structure of one of them was confirmed by X-ray crystallography. A mechanism for the intramolecular oxidative C–N coupling is proposed based on theoretical calculations and cyclic voltammetry analyses.