Trinuclear coordination assemblies of low-spin dicyano manganese(II) (S=1/2) and iron(II) (S=0) phthalocyanines with manganese(II) acetylacetonate, tris(cyclopentadienyl)gadolinium(III) and neodymium(III)

The reaction of (MnPc)-Pc-II, (FePc)-Pc-II or (FePcCl16)-Pc-II with KCN in the presence of cryptand[2.2.2] yielded dicyano-complexes {cryptand(K+)}(2){MII(CN)(2)(macrocycle(2-))}(2-)center dot XC6H4Cl2 (M = Mn and Fe, X = 1 and 2) that were used for the preparation of trinuclear assemblies of the general formula {cryptand(K+)}(2){M-II(CN)(2)Pc center dot(ML)(2)}(2-)center dot nC(6)H(4)Cl(2) (M-II = Mn-II and Fe-II; n = 1, 4 and 5). These assemblies were formed via coordination of two manganese(II) acetylacetonate (ML = Mn-II(acac)(2), S = 5/2), tris(cyclopentadienyl)gadolinium (ML = Cp3GdIII, S = 7/2) or tris(cyclopentadienyl)neodymium (ML = Cp3NdIII, S = 3/2) units to the nitrogen atoms of bidentate cyano ligands. The N(CN)-Mn{Mn-II(acac)(2)} bond is 2.129(3) angstrom long but the bonds are elongated to 2.43-2.49 angstrom for tris(cyclopentadienyl)lanthanides. {Cryptand(K+)}(2){Mn-II(CN)(2)Pc center dot(Mn-II(acac)(2))(2)}(2-)center dot 5C(6)H(4)Cl(2) (2) contains three Mn(II) ions in different spin states (S = 5/2 and 1/2). Strong antiferromagnetic coupling of spins observed between them with the exchange interaction (J) of -17.6 cm(-1) enables the formation of a high S = 9/2 spin state for {Mn-II(CN)(2)Pc center dot(Mn-II(acac)(2))(2)}(2-) dianions at 2 K. The estimated exchange interaction between Mn-II (S = 1/2) and Gd-III (S = 7/2) spins in {Mn-II(CN)(2)Pc center dot(Cp3GdIII)(2)}(2)- is only -1.1 cm(-1), and in contrast to 2, nearly independent Gd-III and Mn-II centers are formed. As a result, no transition to the high-spin state is observed in {Mn-II(CN)(2)Pc center dot(Cp3GdIII)(2)}(2-). The {Mn-II(CN)(2)Pc center dot(Cp3NdIII)(2)}(2-) and{Fe-II(CN)(2)Pc center dot(Cp3NdIII)(2)}(2-) dianions with Cp3NdIII show a decrease of chi T-M values in the whole studied temperature range (300-1.9 K). A similar behaviour was found previously for pristine Cp3NdIII and Cp3NdIII center dot L complexes (L = alkylisocyanide ligand).