The Planar Blatter Radical: Structural Chemistry of 1,4-Dihydrobenzo[e][1,2,4]triazin-4-yls

Two planarized analogues of the prototypical Blatter radical (1), peri‐annulated 1S and 1O, are demonstrated and provide a new platform for molecular and supramolecular engineering, and for tuning electronic and magnetic properties of the radical. Planarization of 1 results in bathochromic shift to the near‐IR region, greater spin delocalization, and anodic shift of the reduction potential only for 1S. Magnetization studies revealed nearly ideal paramagnetic behavior at high temperatures for both radicals 1S and 1O with one‐dimensional ferromagnetic interaction in the former (2J=14.4 cm−1) and antiferromagnetic interactions in 1O at low temperatures. Plane away: The planarized Blatter radical offers expanded spin delocalization, near‐IR absorption, and a new tool for controlling supramolecular assembly, and hence magnetic behavior. The structure provides a new platform for molecular and supramolecular engineering, and for tuning the electronic and magnetic properties of the radical.