Noncovalent synthesis of water-soluble SCS PdII pincer assemblies

This article describes the noncovalent synthesis of water-soluble coordination assemblies based on SCS PdII pincer moieties. Two neutral solubilizing moieties, one based on a linear carbohydrate chain and the other on tetraethylene glycol residues, have been functionalized with pyridine and phosphane ligands. The coordination of the resulting molecules to various hydrophobic, cationic mono- and multimeric SCS PdII pincer systems has been investigated by 1H and 31P NMR spectroscopy, and by MALDI-TOF mass spectrometry. In general, the assemblies with tetraethylene glycol chains display a higher solubility in water than the ones containing linear sugar moieties. A hexapincer core decorated with six linear carbohydrates forms a hydrogel. Finally, a noncovalent water-soluble metallodendrimer having 18 peripheral tetraethylene glycol groups was constructed in a convergent manner.