ABSTRACT
The reaction of MnIIPc, FeIIPc or FeIIPcCl16 with KCN in the presence of cryptand[2.2.2] yielded dicyano-complexes {cryptand(K+)}2{MII(CN)2(macrocycle2-)}2-·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{MII(CN)2Pc·(ML)2}2-·nC6H4Cl2 (MII = MnII and FeII; n = 1, 4 and 5). These assemblies were formed via coordination of two manganese(II) acetylacetonate (ML = MnII(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{MnII(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{MnII(CN)2Pc·(MnII(acac)2)2}2-·5C6H4Cl2 (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 {MnII(CN)2Pc·(MnII(acac)2)2}2- dianions at 2 K. The estimated exchange interaction between MnII (S = 1/2) and GdIII (S = 7/2) spins in {MnII(CN)2Pc·(Cp3GdIII)2}2- is only -1.1 cm-1, and in contrast to 2, nearly independent GdIII and MnII centers are formed. As a result, no transition to the high-spin state is observed in {MnII(CN)2Pc·(Cp3GdIII)2}2-. The {MnII(CN)2Pc·(Cp3NdIII)2}2- and{FeII(CN)2Pc·(Cp3NdIII)2}2- dianions with Cp3NdIII show a decrease of χMT values in the whole studied temperature range (300-1.9 K). A similar behaviour was found previously for pristine Cp3NdIII and Cp3NdIII·L complexes (L = alkylisocyanide ligand).
ABSTRACT
Coordination of tin(II) phthalocyanine to transition metal carbonyl clusters in neutral {SnII(Pc2-)}0 or radical anion {SnII(PcË3-)}- states is reported. Direct interaction of Co4(CO)12 with {SnII(Pc2-)}0 yields a crystalline complex {Co4(CO)11·SnII(Pc2-)} (1). There is no charge transfer from the cluster to phthalocyanine in 1, which preserves the diamagnetic Pc2- macrocycle. The Ru3(CO)12 cluster forms complexes with one or two equivalents of {SnII(PcË3-)}- to yield crystalline {Cryptand[2.2.2](Na+)}{Ru3(CO)11·SnII(PcË3-)}- (2) or {Cryptand[2.2.2](M+)}2{Ru3(CO)10·[SnII(PcË3-)]2}2-·4C6H4Cl2 (3) (M+ is K or Cs). Paramagnetic {SnII(PcË3-)}- species in 2 are packed in π-stacking [{SnII(PcË3-)}-]2 dimers, providing strong antiferromagnetic coupling of spins with exchange interaction J/kB = -19 K. Reduction of Ru3(CO)12, Os3(CO)12 and Ir4(CO)12 clusters by decamethylchromocene (Cp*2Cr) and subsequent oxidation of the reduced species by {SnIVCl2(Pc2-)}0 yield a series of complexes with high-spin Cp*2Cr+ counter cations (S = 3/2): (Cp*2Cr+){Ru3(CO)11·SnII(PcË3-)}-·C6H4Cl2 (4), (Cp*2Cr+){Os3(CO)10Cl·SnII(PcË3-)}-·C6H4Cl2 (5) and (Cp*2Cr+){Ir4(CO)11·SnII(PcË3-)}2- (6). It is seen that reduced clusters are oxidized by SnIV, which is transferred to SnII, whereas the Pc2- macrocycle is reduced to PcË3-. In the case of Os3(CO)12, oxidation of the metal atom in the cluster is observed to be accompanied by the formation of Os3(CO)10Cl with one OsI center. Rather weak magnetic coupling is observed between paramagnetic Cp*2Cr+ and {SnII(PcË3-)}- species in 4, but this exchange interaction is enhanced in 5 owing to Os3(CO)10Cl clusters with paramagnetic OsI (S = 1/2) also being involved in antiferromagnetic coupling of spins. The formation of {SnII(PcË3-)}- with radical trianion PcË3- macrocycles in 2-5 is supported by the appearance of new absorption bands in the NIR spectra and essential Nmeso-C bond alternation in Pc (for 3-5). On the whole, this work shows that both diamagnetic {SnII(Pc2-)}0 and paramagnetic {SnII(PcË3-)}- ligands substitute carbonyl ligands in the transition metal carbonyl clusters, forming well-soluble paramagnetic solids absorbing light in the visible and NIR ranges.
