Hierarchic coordination polymer architectures based on luminescent tungsten-arylidyne building blocks

Molecular self-assemblies based on the electronic complementarity of tungsten arylidynes and N-heteroaromatic ligands were used as a synthetic strategy to construct a new class of luminescent coordination polymers. Various tungsten-arylidyne building blocks for coordination polymers were prepared and spectroscopically studied. Either aromatic alkynes or nitriles provide an ideal source of the tungsten building block library via triple-bond metathesis reaction because their rigidity and directionality enable the rational design of larger molecular assemblies. Both the structural properties and, to some extent, photophysical properties can be pre-programmed into the building blocks to construct a coordination polymer with a desired property.; 1-D linear coordination polymers were built from tungsten building blocks with various lengths of side chains and bridging N-ligands. By adding long side chains on the aromatic core of the metal building block, the solubility of the polymers has been improved. The emission properties of these polymers were compared with those of the tungsten building blocks.; A series of 3-D square grid coordination polymer frameworks (10 A x 10 A) constructed by combining W-N dative bonds, CH/O hydrogen bonds, and CH/pi interactions are described. These hierarchically assembled 3-D grids from the 1-D linear chains are stabilized by CH/pi interactions between the chains, and the structural integrity is insensitive to the electronic nature of pi system. We have further investigated whether the assembly of building components with various lengths gives a grid network with different dimensions.; Either varying angles between the functional sites or controlling the tungsten coordination geometry of the building blocks provides nonlinear polymer chains. Several intriguing coordination polymer architectures based on angular tungsten building blocks are described. Aromatic-aromatic interactions play the deciding role in determining the hierarchic structures of this broader class of materials.