Titanocene aqua-complex

To explain the unprecedented HATs from water it was proposed that the co-ordination of water to Ti(III) might weaken the strength of the O-H bond. In this manner a single-electron transfer from titanium to oxygen might facilitate the HAT from the titanocene aqua-complex 42 to the free radicals (Scheme 29). 

Theoretical calculations supported this hypothesis, indicating a bond-dissociation energy (BDE) for the titanocene aqua-complex 42 of only 49.4 kcal mol-1, which represents a decrease of almost 60 kcal mol-1 compared to the calculated BDE of H20 (Scheme 30) [73, 74],... 

The hydrolysis of metallodrugs is often the key step in their activation, but the timescale is extremely variable, ranging from tenths of a second for titanocene dichloride, to hours for cisplatin, to days for carboplatin. We found on SPE that the interaction of cisplatin with DNA increases with the solution ageing time, especially at low concentrations of chlorides [50]. Each complex was therefore preactivated for 60 minutes before testing interaction with DNA, in order to permit the transformation into the active aqua species, for the complexes needing this incubation time, and to compare the behavior at the same solntion ageing time, for the complexes with a different rate of hydrolysis. 

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See also in sourсe #XX -- [ ]

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