1. Department of Chemistry, University of Newcastle, Newcastle upon Tyne, NEl 7RU, UK Fax: (internat.) +44(191)222 6929 E‐mail: W. Clegg@newcastle.ac.uk
2. Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, Gl 1XL, UK Fax: (internat.) +44(141)5520876 E‐mail: R.E.Mulvey@strath.ac.uk