The University of Southampton
University of Southampton Institutional Repository

ZrIV-tetraphenylporphyrinates as nuclease mimics: Structural, kinetic and mechanistic studies on phosphate diester transesterification

Stulz, Eugen, Bürgi, Hans-Beat and Leumann, Christian (2000) ZrIV-tetraphenylporphyrinates as nuclease mimics: Structural, kinetic and mechanistic studies on phosphate diester transesterification Chemistry - A European Journal, 6, (3), pp. 523-536. (doi:10.1002/(SICI)1521-3765(20000204)6:3<523::AID-CHEM523>3.0.CO;2-1). (PMID:10747420).

Record type: Article

Abstract

The Zr-IV-tetraphenylporphyrinates Zr(TPP)(X,X'), (X,X' = -OAc, -OMe, Cl-) 4-6, 8 were prepared and their complexing properties as well as catalytic properties towards solvolysis of the phosphate diesters hpp (2), dmp (3) and pmp (16) characterised. The diesters 2 and 16, representing model phosphates for RNA and DNA, were substrates for the catalyst Zr(TPP)CI, (4), and rate accelerations over background by 6-9 orders of magnitude were measured. These accelerations are comparable to those of dinuclear transition metal catalysts and lanthanide ions. Catalytic turnover was observed. Kinetic studies revealed that the catalytically active species of 4 in the solvolysis of 2 and 16 in methanol-containing solvents are dinuclear complexes containing either one or two phosphate esters depending upon the phosphate concentration. Besides the usual solvolysis pathway of the RNA model hpp (2), which proceeds via the cyclophosphate 20, a second, unusual pathway via direct substitution of the hydroxypropyl substituent was found. X-ray analysis of the Zr(TPP)(dmp) complex 19 revealed a dinuclear structure with two bridging dmp ligands and one monomethyl phosphate unit. In 19 one of the two dmp residues occurs in a very unusual high energy ac,ap conformation. Based on this structure and on the kinetic data, mechanistic models for the two solvolysis reaction pathways were developed. From an extensive CSD search on phosphodiester structures no correlation between P-O ester bond lengths and diester conformations could be found. However, P-O ester bonds decrease in length with increasing formal charge of the complexing metal ions. This underlines the higher importance of electrostatic activation relative to stereoelectronic effects in phosphodiester hydrolysis.

Full text not available from this repository.

More information

Published date: 4 February 2000
Keywords: bioinorganic chemistry, catalysts, phosphatases, porphyrinoids, zirconium

Identifiers

Local EPrints ID: 191675
URI: http://eprints.soton.ac.uk/id/eprint/191675
ISSN: 0947-6539
PURE UUID: 66120f72-9567-49a1-98a8-ba5d72b5b135

Catalogue record

Date deposited: 23 Jun 2011 12:53
Last modified: 18 Jul 2017 11:34

Export record

Altmetrics

Contributors

Author: Eugen Stulz
Author: Hans-Beat Bürgi
Author: Christian Leumann

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×