A Noninterpenetrated Molecular Ladder with Hydrophobic Cavities

摘要

Crystal engineering ol supramolecular architectures sustained by coordinate covalent bondsor hydrogen bonds represents a rapidly expanding field that offers potential for rational development of new classes of functional solids. It is now establishedthat the architectures of coordination polymers can be reliably predicted, since previously known metal coordination environments are propagated into one- (ID), two- (2D). and three-dimensional (3D) motifs with rigid multitopic organic "spacer" ligands.Recent examples include diamondoid, hon-eycomb, grid, ladder, brick wall, and octahedral frameworks from tetrahedral, trigonal, and octahedral metal templates (e.g. Zn~(II), Cd~(II), Ag~I, Cu~I, Scheme-1). Unfortunately, if the void created in this way is more than 50% of the crystal by volume, it is almost always reduced by interpenetration or self-inclusion. We report herein what is to our knowledge the first example of a noninterpenetrated molecular ladder: [Co(NO_3)_2(4,4'-bpy)_(1.5)]_∞ (1) (4,4'-bpy = 4,4'-bipyridine), an open framework infinite ladder that clathrates small organic guests despite possessing a cavity that is large enough to self-include.