Distance between Metal Centres Affects Catalytic Efficiency of Dinuclear CoIII Complexes in the Hydrolysis of a Phosphate Diester. Issue 39 (25th June 2018)

• Record Type: Journal Article
• Authors: Bencze, Eva Szusanna; Zonta, Cristiano; Mancin, Fabrizio; Prins, Leonard J.; Scrimin, Paolo
• Is Part Of: European journal of organic chemistry. Issue 39(2018)
• Page Start: 5375
• Page End: 5381
• Publication Date: 2018-06-25
• Subjects: Enzyme models -- Metalloenzymes -- Hydrolysis -- Phosphate cleavage -- Cobalt -- Dinuclear; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201800300
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : 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. Abstract : The effect on the hydrolysis of bis‐ p ‐nitrophenylphosphate catalysed by dinuclear Co III complexes designed in such a way that the two Co III ions cannot be contemporaneously involved in the complexation of the substrate, show a remarkable dependence on their distance.