ISSN:
1434-1948
Keywords:
O-Coordinated amides
;
Platinum
;
O-to-N Isomerization
;
Atropisomers
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
O-bonded amide complexes of platinum(II), which are stable in acetone solution and which undergo solvolysis in neat water with a rate constant as slow as 8.7·10-5 s-1, are reported. The structure of a sample compound [Pt(Me5dien){O-MeC(O)NH2}](CF3SO3)2 has been solved by X-ray diffraction allowing comparison with related N-bonded (amide)platinum complexes. Isomerization from O-amide to N-amidate species takes place instantaneously under basic conditions. Protonation of the amidate species leads to the N-bonded amide. N-bonded amides, like the N-bonded amidates, represent the thermodynamically preferred species due to the higher affinity of platinum for nitrogen donors. In contrast O-bonded amides owe their stability to their kinetic inertness, where a high pH is required for deprotonation of the NH2 moiety, the leading step in the isomerization process. In the case of the 2-pyridone complex, the O-bonded form is unstable and isomerizes spontaneously to the N-bonded form, due to the higher acidity of the protonated pyridine-like nitrogen atom. Two rotamers are present in both the N-pyridone and N-pyridonate species. Hindered rotation stems from the steric rigidity of both rotating moieties [(Me5dien)Pt and pyridone/pyridonate].
Type of Medium:
Electronic Resource
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