Pseudo-polymorphism of a camphor α-cyclodextrin complex.

Crystalline products of vapor diffusion of an alcoholic solution of 1R,4R-camphor into an aqueous solution of α-cyclodextrin were prepared and subjected to X-ray structure analysis. Two different forms were obtained: a dimeric cavity formed by head-to-head association of cyclodextrin (phase A), and a complex set of monomeric cavities (phase B). Both contain camphor molecules orientationally disordered inside cavities. The structures are solvated by mixtures of water and ethanol. The structures significantly differ in chemical stabilities. Whilst phase A is relatively stable with respect to guest desorption, phase B rapidly reacts to change of its chemical environment manifested by cracking of crystals in solution. The phenomenon has been recorded and a short movie is included in the supplementary data.

A shape-persistent quadruply interlocked giant cage catenane with two distinct pores in the solid state.

Discrete interlocked three-dimensional structures are synthetic targets that are sometimes difficult to obtain with "classical" synthetic approaches, and dynamic covalent chemistry has been shown to be a useful method to form such interlocked structures as thermodynamically stable products. Although interlocked and defined hollow structures are found in nature, for example, in some viruses, similar structures have rarely been synthesized on a molecular level. Shape-persistent interlocked organic cage compounds with dimensions in the nanometer regime are now accessible in high yields during crystallization through the formation of 96 covalent bonds. The interlocked molecules form an unprecedented porous material with intrinsic and extrinsic pores both in the micropore and mesopore regime.

A permanent mesoporous organic cage with an exceptionally high surface area.

Recently, porous organic cage crystals have become a real alternative to extended framework materials with high specific surface areas in the desolvated state. Although major progress in this area has been made, the resulting porous compounds are restricted to the microporous regime, owing to the relatively small molecular sizes of the cages, or the collapse of larger structures upon desolvation. Herein, we present the synthesis of a shape-persistent cage compound by the reversible formation of 24 boronic ester units of 12 triptycene tetraol molecules and 8 triboronic acid molecules. The cage compound bears a cavity of a minimum inner diameter of 2.6 nm and a maximum inner diameter of 3.1 nm, as determined by single-crystal X-ray analysis. The porous molecular crystals could be activated for gas sorption by removing enclathrated solvent molecules, resulting in a mesoporous material with a very high specific surface area of 3758 m(2) g(-1) and a pore diameter of 2.3 nm, as measured by nitrogen gas sorption.

The surprising and stereoselective formation of P2C10 cages by the reduction of Cp*PCl2.

Reactions of Cp*PCl2 with Group 13 reducing agents result in a cascade of P-C, P-P and C-C bond forming reactions and the stereoselective formation of P2C10 cages.