Formation of giant cyclic complexes by the assembly of small, flexible units is demonstrated by connecting 14 artificial tripeptides (1) with 14 Ni(II) ions. Although tripeptide 1 is very flexible because of the presence of three CH groups in the main chain, it formed a tetradecanuclear cyclic complex ([1Ni]) with a large cavity (diameter: ca. 2 nm).
View Article and Find Full Text PDFHumidity-responsive ON/OFF switching of CO inclusion, associated with cooperative structural changes of heterogeneous cavities in crystalline peptide Ni macrocycles, 1⋅NO , is demonstrated. The structural transformation between an "open form" and a "closed form" was caused by reversible water uptake into one of the cavities. The adsorption behavior of CO was studied with and without water vapor, combined with gas-composition analysis by using gas chromatography.
View Article and Find Full Text PDF