Bis(ethylenedithio)tetrathiafulvalene and dibenzotetrathiafulvalene salts with dicyanoiron(III) phthalocyanine anions

Electrooxidation of bis(ethylenedithio)tetrathiafulvelene (BEDT-TTF) and dibenzotetrathiafulvelene (DB-TTF) in the presence of dicyanoiron(II) phthalocyanine (Pc) dianions in form of the {Cryptand(K+)}2{FeII(CN)2Pc}2- salt has been studied in o-dichlorobenzene and acetonitrile solutions (where Cryptand is cryptand[2.2.2]). Initially iron(II) is oxidized to iron(III) and after that tetrathiafulvelenes are oxidized forming crystalline salts (BEDTTTF center dot+){FeIII(CN)2Pc}- center dot C6H4Cl2 (1) and (DB-TTF center dot+){FeIII(CN)2Pc}- center dot C6H4Cl2 (2). Both salts contain closely packed 2D layers composed of the {FeIII(CN)2Pc}- anions and cationic layers containing solvent molecules. Since cations cannot partially oxidize Pc in these salts, two S = 1/2 spins are positioned on FeIII and the cations. The chi MT values are 0.90 and 0.87 emu center dot K/mol per formula unit at 300 K. Antiferromagnetic coupling of spins is observed in 1 and 2 due to both Fe-Cation coupling of -0.4 and -3.5 cm-1 and Fe-Fe couplings of -3.5 and -7.9 cm-1, respectively. Due to its smaller size of DB-TTF+, complex 2 has denser packing of the components and shows stronger exchange couplings. An unusual compound forms when DB-TTF and {FeII(CN)2Pc}2- are oxidized together in acetonitrile: (DB-TTF0)2{Cryptand(K+)}{FeIII(CN)2Pc}- (3) where charges on DB-TTF and Fe are closer to zero and +3, respectively. The {FeIII(CN)2Pc}- anions form layers in 3 among which chains with short C,N...C,N contacts between Pc can be outlined. Only weak intermolecular antiferromagnetic coupling is manifested in 3 with estimated zJ value of -1.6 cm-1.