Coordination-driven self-assembly of discrete supramolecular structures.

摘要

Coordination-driven self-assembly of discrete supramolecular structures is a rapidly growing subfield of modern supramolecular chemistry. Over the last years, different strategic approaches to this type of self-assembly have been developed that allowed for the rational design and synthesis of a great variety of transition metal based two- and three-dimensional supramolecular structures. Many of these approaches rely on the building block molecules, from which the assemblies are formed, to provide the information required for the formation of the desired supramolecular structure.; This dissertation presents a continuing development of the directional bonding approach to the design and synthesis of discrete supramolecular structures. Several new assemblies of predetermined geometry are described, along with their study by modern analytical techniques.; A number of supramolecular triangles were assembled from pyridine-containing linear linkers and a novel diplatinum 60° corner unit. The triangles have sides ranging in length from 2.7 to 3.5 nm and molecular masses as high as 5396 amu. The triangles are not in detectable equilibrium with other macrocycles. The crystal structure of the smaller assembly shows an ∼1.4 nm cavity; the crystal packing forms open, triangular channels. The macrocycles were studied by multinuclear nuclear magnetic resonance, elemental analysis and electrospray mass spectrometry.; The same 60° corner unit was used in assembly of a three-dimensional structure of D_3h symmetry. Additional D_3h-symmetrical cages were constructed from a set of novel building blocks, including three isostructural platinum-containing tripods and a unique pyridine-based donor “clip”—a ditopic tecton with nearly parallel coordination directions. Tetrahedral carbon, silicon and phosphorus were used as structure-defining elements in these coordination-based cages. The formation of these assemblies was supported by multinuclear NMR, ESI-FT-ICR mass spectrometry and elemental analysis data.; Finally, the carbon and silicon-centered tripod tectons were used in the formation of nanoscopic dodecahedra. The cages were studied by NMR, transmission electron microscopy and photon correlation spectroscopy. In a related study, the combination of the 60° corner unit with tetrapyridylporphyrin resulted in formation of a highly symmetrical assembly with a presumed structure of a face-directed trigonal prism.