New sandwich complexes of praseodymium(iii) containing triazacyclohexane ligands

N-substituted 1,3,5-triazacyclohexanes (R3TAC) react with praseodymium trifluoromethane sulfonates [Pr(OTf)3] to give the corresponding complexes, containing one or two R3TAC ring(s) coordinated to praseodymium, depending on R. The crystal and molecular structures of these compounds have been determined by X-ray diffraction. The complex containing two coordinated R3TAC is mononuclear, while the complex containing one R3TAC is dinuclear with three triflate bridges. NMR diffusion studies indicate that these structures also occur in benzene solution.