Chiral Crystalline Sponges for the Absolute Structure Determination of Chiral Guests

Chiral crystalline sponges with preinstalled chiral references were synthesized. On the basis of the known configurations of the chiral references, the absolute structures of guest compounds absorbed in the pores of the crystalline sponges can be reliably determined without crystallization or chemical modification

Networked-Cage Microcrystals for Evaluation of Host–Guest Interactions

We have developed a new synthetic protocol for the preparation of a microcrystalline powder (median size: <i>X</i>₅₀ = 25 μm) of networked M₆L₄ cages <b>1a</b> for the stationary phase of an affinity column on a greater than 50 g scale. Analogously to large single crystals <b>1b</b> (<i>X</i>₅₀ ≈ 0.5 mm), microcrystals <b>1a</b> accommodate guest molecules tetrathiafulvalene (TTF) and fullerene (C₆₀) at up to 32 and 35 wt %, respectively. Importantly, the host–guest interactions within networked cages could be evaluated in terms of the retention time from HPLC analysis by using microcrystals <b>1a</b> as the stationary phase. In this way, favorable guests for networked cages <b>1</b> and even solution M₆L₄ cage <b>2</b> could easily be assessed by HPLC