Synthesis and Isomerization of N‑Fused Tetraphenylporphyrin Ruthenium(II) Complexes

Three possible isomers of N-fused tetraphenylporphyrin ruthenium complexes, Ru­(NFTPp)­Cl­(CO)₂ (<b>2a</b>–<b>c</b>), were isolated and fully characterized by NMR, IR, CV, UV–vis-NIR absorption, and X-ray crystallographic analyses. Each isomer was stable at ambient conditions and isomerization among <b>2a</b>–<b>c</b> occurred at elevated temperature both in solution and in a solid state, through the intramolecular rotational pathways. Electronic structures of <b>2a</b>–<b>c</b> were analyzed in detail by DFT study to reveal appreciable differences in the interaction between the NFTPp ligand and the Ru–Cl moiety