Role of Multicentered Bonding in Controlling Magnetic Interactions in π-Stacked Bis-dithiazolyl Radical

Crystal structure analyses and quantum chemical calculations on the bis-dithiazolyl radical (BTA center dot) reveal that this neutral radical forms stable pi-stacked multicentered bonding in the dimer. The overall macroscopic magnetic behavior of the crystal of this molecule is controlled by the strength of this interaction. Increasing the intermolecular distance between BTA center dot leads to an antiferromagnetic -> ferromagnetic crossover in this class of organic conductors. BTA center dot along with the phenalenyl radical (PHEN center dot) represents a new class of neutral pure aromatic organic radicals where such multicentered bonding exists.