Phosphorylation of β-cyclodextrin enhances binding with Ru(II)polypyridyl complexes, and promotes selectivity based on chirality and ligand hydrophobicity. For [Ru(phen)2dppz]2+, inclusion of dppz results in a dramatic increase in luminescence with multiple lifetimes. The sensitive response of photophysics to the environment reveals nanoscale variation of polarity.
![Graphical abstract: [Ru(phen)2dppz]2+ luminescence reveals nanoscale variation of polarity in the cyclodextrin cavity](http://hg.y866.cn/compound/lib/scimg/usr/1/C5CC09755J.jpg)