The synthesis, self assembly and magnetic properties of a polychlorotriphenylmethyl radical, substituted with six meta-carboxylic groups, are reported showing that radical–radical hydrogen bonds in the solid state yield to very weak intermolecular ferromagnetic interactions.
The synthesis of the highly strained tris(alpha,alpha-bis(pentachlorophenyl)-2,4,5,6-tetrachlorotolyl)methane (8), which is the precursor of the first generation of the polyradical series III, has been achieved by exhaustive chlorination of compound 11. Stepwise divergent synthesis, by successive Friedel-Crafts reactions, of the precursors of dendritic series II and III was not possible since the limit generation was reached in the earlier synthetic steps due to high steric congestion. Several polyradical mixtures derived from 8 have also been prepared, being stable under ambient conditions. The formation, electrochemistry, and magnetic properties of these polyradical species are discussed. The steric hindrance of highly chlorinated hydrocarbon 8 prevents the formation of tetraradical 15.
Three-Dimensional Six-Connecting Organic Building Blocks Based on Polychlorotriphenylmethyl Units—Synthesis, Self-Assembly, and Magnetic Properties
process to yield two-dimensional (2D) hydrogen-bonded structures ([1(Et(2)O)(3)] and [4(Et(2)O)(3)]). The presence of direct hydrogen bonds between the radicals in the latter phase of 1 gives rise to very weak ferromagnetic intermolecularinteractions at low temperatures, whereas when the radicals are isolated by THF molecules these interactions are antiferromagnetic and very weak. The role played by the