Haibin Deng

Coordination chemistry of lanthanides with transition metal anions

In coordinating solvents such as CH3CN, pyridine, and DMF, solvent separated ion pairs result when the transition metal centers and the bidentate ligands of the transition metal anions are not sufficiently nucleophilic to coordinate to lanthanide ions. With highly nucleophilic transition metal carbonylates, direct transition metal-lanthanide bonds as well as lanthanide-isocarbonyl linkages are possible. Direct bonds between ytterbium and iron are present in [(CH3CN)3YbFe(CO)4]2·CH3CN∞ a one-dimensional ladder, and (CH3CN)3YbFe(CO)4∞, a two dimensional sheet. The ladder polymers (DMF)4EuNi(CN)[in4]∞ and (DMF)4EuPt(CN)4∞, are formed2− in DMF. In these complexes the Eu(II) and transition metals are bridged by the cyanide ions, and no direct lanthanide-transition metal bonds are present. Two types of one-dimensional polymers of general formula (DMF)10Ln2[M(CN)4]3∞ that contain a cyanide bridge between the lanthanide(III) and the transition metal(II) have been prepared. Type A: Ln = Yb, Er, Sm; M = Ni. Type B: Ln = Yb, M = Pt; Ln = Eu, M = Ni. Both types of complex contain the same repeating unit. But the type A complex contains diamond shaped Ln2M2 cores linked together in an infinite array by M(CN)42− anions generating a single strand chain, while the type B complex contains two parallel zigzag chains that are inverted with respect to each other and are linked by M(CN)42− ions. By blocking one of the available trivalent lanthanide coordination sites with a chloride ion, the commonly observed zigzag chain structure of the tetracyanometallates(II) is adopted by (DMF)5Sm[Ni(CN)4]Cl∞ and (DMA)4YbNi(CN)4Cl∞