Complexes of transition metal carbonyl clusters with tin(ii) phthalocyanine in neutral and radical anion states: methods of synthesis, structures and properties

Coordination of tin(ii) phthalocyanine to transition metal carbonyl clusters in neutral {Sn-II(Pc2-)}(0) or radical anion {Sn-II(Pc3-)}(-) states is reported. Direct interaction of Co-4(CO)(12) with {Sn-II(Pc2-)}(0) yields a crystalline complex {Co-4(CO)(11)center dot Sn-II(Pc2-)} (1). There is no charge transfer from the cluster to phthalocyanine in 1, which preserves the diamagnetic Pc2- macrocycle. The Ru-3(CO)(12) cluster forms complexes with one or two equivalents of {Sn-II(Pc3-)}(-) to yield crystalline {Cryptand[2.2.2](Na+)}{Ru-3(CO)(11)center dot Sn-II(Pc3-)}(-) (2) or {Cryptand[2.2.2](M+)}(2){Ru-3(CO)(10)center dot[Sn-II(Pc3-)](2)}(2-)center dot 4C(6)H(4)Cl(2) (3) (M+ is K or Cs). Paramagnetic {Sn-II(Pc3-)}(-) species in 2 are packed in pi-stacking [{Sn-II(Pc3-)}(-)](2) dimers, providing strong antiferromagnetic coupling of spins with exchange interaction J/k(B) = -19 K. Reduction of Ru-3(CO)(12), Os-3(CO)(12) and Ir-4(CO)(12) clusters by decamethylchromocene (Cp*Cr-2) and subsequent oxidation of the reduced species by {(SnCl2)-Cl-IV(Pc2-)}(0) yield a series of complexes with high-spin Cp*Cr-2(+) counter cations (S = 3/2): (Cp*Cr-2(+)){Ru-3(CO)(11)center dot Sn-II(Pc3-)}(-)center dot C6H4Cl2 (4), (Cp*Cr-2(+)){Os-3(CO)(10)Cl center dot Sn-II(Pc3-)}(-)center dot C6H4Cl2 (5) and (Cp*Cr-2(+)){Ir-4(CO)(11)center dot Sn-II(Pc3-)}(2)(-) (6). It is seen that reduced clusters are oxidized by Sn-IV, which is transferred to Sn-II, whereas the Pc2- macrocycle is reduced to Pc3-. In the case of Os-3(CO)(12), oxidation of the metal atom in the cluster is observed to be accompanied by the formation of Os-3(CO)(10)Cl with one Os-I center. Rather weak magnetic coupling is observed between paramagnetic Cp*Cr-2(+) and {Sn-II(Pc3-)}(-) species in 4, but this exchange interaction is enhanced in 5 owing to Os-3(CO)(10)Cl clusters with paramagnetic Os-I (S = 1/2) also being involved in antiferromagnetic coupling of spins. The formation of {Sn-II(Pc3-)}(-) with radical trianion Pc3- macrocycles in 2-5 is supported by the appearance of new absorption bands in the NIR spectra and essential N-meso-C bond alternation in Pc (for 3-5). On the whole, this work shows that both diamagnetic {Sn-II(Pc2-)}(0) and paramagnetic {Sn-II(Pc3-)}(-) ligands substitute carbonyl ligands in the transition metal carbonyl clusters, forming well-soluble paramagnetic solids absorbing light in the visible and NIR ranges.