The use of suitable predetermined building blocks has assumed an increasing relevance in recent times in the crystal engineering of coordination frameworks [1] that have potential interest as zeolite-like materials. [2] In this regard, much d) N. ] Racemic 1 was prepared by the lithiation of 2-alkynyl-5bromopyrimidine followed by treatment with 2-methylpropanal.[8] Preparation of (S)-1 with ca. 0.00005 % ee. Pyrimidyl alkanol (S)-1 (1.5 mg, > 99.5 % ee) was dissolved in ethyl acetate (or benzene) to make a standardized solution of (S)-1 (3.2 î 10 À6 mol L À1 ). The solution (50 mL) was added to a solution of racemic 1 (75.1 mg) in ethyl acetate (or benzene). Then, a part of the solution was transferred to another flask, and the removal of solvent gave (S)-1 with ca. 0.00005 % ee (9.9 mg). Dissolution of the whole (S)-1 in 4.3 mL of cumene produced a 9.9 î 10 À3 m solution of (S)-1 with ca. 0.00005 % ee. [9] a) K. Soai, S. Niwa, Chem. Rev. 1992, 92, 833 ± 856; b) L. Pu, H.-B. Yu, Chem. Rev. 2001, 101, 757 ± 824. [10] After our experiments were completed, Singleton and Vo reported asymmetric autocatalysis using (R)-(2-methylpyrimidyl)alkanol [5b] with the order of 10 À5 % ee [a) D. A. Singleton, L. K. Vo, J. Am. Chem. Soc. 2002, 124, 10 010 ± 10 011]. However, they used only the catalyst with the R configuration. We believe that it is essentially important to examine the asymmetric autocatalysts of both configurations. The reasons are as follows:1) The chirality level of the catalyst on the order of 10 À5 % ee is Sato,
Solid-state luminescent materials with long lifetimes are the subject of ever-growing interest from both a scientific and a technological point of view. However, when dealing with organic compounds, the achievement of highly efficient materials is limited by aggregation-caused quenching (ACQ) phenomena on one side and by ultrafast deactivation of the excited states on the other. Here, we report on a simple organic molecule, namely, cyclic triimidazole (CHN), 1, showing crystallization-induced emissive (CIE) behavior and, in particular, ultralong phosphorescence due to strong coupling in H-aggregated molecules. Our experimental data reveal that luminescence lifetimes up to 1 s, which are several orders of magnitude longer than those of conventional organic fluorophores, can be realized under ambient conditions, thus expanding the class of organic materials for phosphorescence applications.
The synthesis, structural changes, and nitrogen gas sorption isotherm of a porous metal−organic framework (PMOF) comprising stacked two-dimensional sheets are reported. This compound easily loses guest molecules and shrinks its interlayer distance. The guest-free species show a unique double-step sorption isotherm. Sorption and X-ray structural analyses have clarified that the first uptake is a micropore filling, while the second uptake originates from a clathrate formation. This explains the total sorption amount corresponding to about the double of the original void volume of the crystals.
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