I. Theoretical investigations of spin-spin interactions: Semiempirical estimations of exchange parameters for diradical metalloporphyrin cations and zero-field splitting parameters for conjugated diradicals. II. Synthesis and characterization of radical-s

heoretical investigations of the exchange parameter J for various diradical metalloporphyrin cations gives an indication of the effectiveness of various linkers in promoting exchange coupling between unpaired electrons. The trend in the exchange interaction (estimated from the singlet-triplet energy gap) is explained by the spin coupler analysis method. Efforts to synthesize the metalloporphyrin-based building blocks incorporating phenylgalvinoxyl as the peripheral spin-containing unit are described. We have shown that Suzuki coupling of pinacol arylboronates with meso-bromoporphyrins is another method which can be used to synthesize meso-substituted porphyrins. Finally, a new empirical approximate method for estimating the zero field splitting parameter D for conjugated diradicals is also presented. The method uses the average...