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Distance between Metal Centres Affects Catalytic Efficiency of Dinuclear Co III Complexes in the Hydrolysis of a Phosphate Diester
Author(s) -
Bencze Eva Szusanna,
Zonta Cristiano,
Mancin Fabrizio,
Prins Leonard J.,
Scrimin Paolo
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201800300
Subject(s) - chemistry , catalysis , hydrolysis , phosphate , substrate (aquarium) , reaction rate constant , metal , transition metal , inorganic chemistry , ion , metal ions in aqueous solution , medicinal chemistry , kinetics , stereochemistry , organic chemistry , oceanography , physics , quantum mechanics , geology
Dinuclear Co III complex catalysed hydrolysis of bis‐ p ‐nitrophenylphosphate, a DNA model substrate, is reported. The catalysts were designed in such a way that the two Co III ions cannot be contemporaneously involved in the complexation of the substrate or transition state. Experimental evidence of the involvement of such a remote metal centre in the catalysis of the hydrolysis of a phosphate diester is provided. This contribution amounts to a ca. 64‐fold rate acceleration for the second‐order rate constants of the best dinuclear complex over the mononuclear one, which is apparently due to general acid or H‐bonding catalysis. Furthermore, there is significant distance dependence for this catalytic contribution and, in this case, it appears that the best distance (as estimated by DFT calculations) is ca. 7.7 Å. This may indicate that the presence of metal centres in close proximity, as required for mechanism proposals in which all metals are directly involved in transition‐state coordination, is not the only option for rate acceleration in natural phosphate hydrolysis.