文摘
A bulky platinum triamine complex, [Pt(Me5dien)(NO3)]NO3 (Me5dien = N,N,N′,N′,N′′-pentamethyldiethylenetriamine) has been prepared and reacted in D2O with N-acetylmethionine (N-AcMet) and guanosine 5′-monophosphate (5′-GMP); the reactions have been studied using 1H NMR spectroscopy. Reaction with 5′-GMP leads to two rotamers of [Pt(Me5dien)(5′-GMP-N7)]+. Reaction with N-AcMet leads to formation of [Pt(Me5dien)(N-AcMet-S)]+. When a sample with equimolar mixtures of [Pt(Me5dien)(D2O)]2+, 5′-GMP, and N-AcMet was prepared, [Pt(Me5dien)(5′-GMP-N7)]+ was the dominant product observed throughout the reaction. This selectivity is the opposite of that observed for a similar reaction of [Pt(dien)(D2O)]2+ with 5′-GMP and N-AcMet. To our knowledge, this is the first report of a platinum(II) triamine complex that reacts substantially faster with 5′-GMP than with N-AcMet; the effect is most likely due to steric clashes between the methyl groups of the Me5dien ligand and the N-AcMet.