Cyclic, trinuclear PdII complex of cytidine with pronounced double cone structure

Reaction of PdII(tmeda) (tmeda = N,N,N′,N′-tetramethylethylenediamine) with the RNA nucleoside cytidine (Cytd) yields a cyclic nucleoside complex containing three metal entities and three cytidine anions, with metal cross-links involving N(3) and N(4)H− sites. [{Pd(Cytd−-N3, N4)(tmeda)}3](ClO4)3 · 6H2O has a characteristic double cone structure with the methyl groups of the tmeda ligands representing the lower rim and the ribose moieties forming the upper rim. The Pd3 triangle is equilateral (5.193(1) Å). In the solid state structure, one of the ClO4- counter ions links the lower and the upper rims of adjacent cones, thereby leading to a 1D chain. No host–guest chemistry has been detected with a series of N-heterocyclic ligands in water.