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 Mn II Pc, Fe II Pc or Fe II PcCl 16 with KCN in the presence of cryptand[2.2.2] yielded dicyano-complexes {cryptand(K + )} 2 {M II (CN) 2 (macrocycle 2- )} 2- · X C 6 H 4 Cl 2 (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·(ML) 2 } 2- · n C 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 = Cp 3 Gd III , S = 7/2) or tris(cyclopentadienyl)neodymium (ML = Cp 3 Nd III , 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) Å long but the bonds are elongated to 2.43-2.49 Å for tris(cyclopentadienyl)lanthanides. {Cryptand(K + )} 2 {Mn II (CN) 2 Pc·(Mn II (acac) 2 ) 2 } 2- ·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·(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·(Cp 3 Gd III ) 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·(Cp 3 Gd III ) 2 } 2- . The {Mn II (CN) 2 Pc·(Cp 3 Nd III ) 2 } 2- and{Fe II (CN) 2 Pc·(Cp 3 Nd III ) 2 } 2- dianions with Cp 3 Nd III show a decrease of χ M T values in the whole studied temperature range (300-1.9 K). A similar behaviour was found previously for pristine Cp 3 Nd III and Cp 3 Nd III ·L complexes (L = alkylisocyanide ligand).