Dipyrimidylamine and tripyrimidylamine as chelating N-donor ligands

Dipyrimidylamine (dipm) and tripyrimidylamine (tripm) are reported. A bidentate tripm ruthenium complex, [RuCl(η6-p-cymene)(κ2-tripm)]SbF6, is synthesized and structurally characterized. The presence of an intramolecular CH⋯N hydrogen bond is proposed between the cymene CH and a ring nitrogen in an uncoordinated pyrimidine ring. IR data on [Mo(CO)4(dipm)] suggest that the Tolman electronic parameter of the dipm ligand is similar to that of 2×PPh3. ML bonding may be weaker for pyrimidine versus pyridine because κ2-tripm complexation is apparently more favorable relative to the κ3-form than is the case for tripyridylamine.