For Abstract see ChemInform Abstract in Full Text.

No abstract

A technique, based on 1 H NMR and IR experiments, to characterise intramolecular hydrogen bonds in aqueous medium in a series of amino, amido and ammonium sugar derivatives has been established. Three groups of molecules, representing amides (4, 5 and 6), amines (7 and 8) and ammonium salts (chlorides 9 and 10, and phosphates 11 and 12), with different relative configurations of their functional groups, have been investigated to assess the effect of the nature and the stereochemistry of these groups on the hydrogen-bonding features of the sugar. The deduced features in water solution are compared to those obtained previously in nonpolar solvents. The phosphate salts of amines 7 and 8 (11 and 12)

Most of the porphyrin-recognition chemistry we have investigated previously has centred on kinetically labile metal-ligand interactions, such as Z-N and Ru-N. Our interest in the broader scope of molecular recognition required a metal with the ability to specifically recognise non-nitrogen-based ligands, with a significantly different binding interaction to distinguish it from nitrogen-based analogues. In this report we describe interactions of Sn(IV) porphyrins that bind oxygen-based ligands and for which the Sn(IV)bond;O bond is in slow exchange on the NMR timescale. A series of carboxylate complexes is employed to highlight the structural/geometric features of porphyrin monomers and cyclic oligomers. Where more than one porphyrin unit is present in a molecular scaffold, we report the effect of carboxylate binding on the complex when the two porphyrins contain different metals (typically Sn(IV) and Zn(II)). The unexpected spectroscopic and structural properties of the Sn(2)(9-anthroic acid)porphyrin dimer are also reported.

No abstract