Supramolecular arrays based on dimetal building units

Supramolecular chemistry is today a major thrust area, a significant part o f which is based on the use of metal atoms or ions as key elements in promo ting the assembly of and dictating the main structural features of the supr amolecular products. Most of the work has been done with single metal atoms or ions in this role, but considerable success has already been achieved b y employing M-M bonded dimetal entities instead. We review here the work do ne in our laboratory. Metal-metal bonded cationic complexes of the [M-2(DAn iF)(n)(MeCN)(a-2n)]((4-n)+) type, where M = Mo or Rh and DAniF is an N,N',- di-p-anisylformamidinate anion, have been used as subunit precursors and th en linked by various equatorial and axial bridging groups such as polycarbo xylate anions, polypyridyls, and polynitriles. Characterization oi the prod ucts by single-crystal X-ray diffraction, CV, DPV, NMR, and other spectrosc opic techniques has revealed the presence of discrete tetranuclear (pairs o r loops), hexanuclear (triangles), octanuclear (squares), and dodecanuclear (cages) species and one-, two-, or three-dimensional molecular nanotubes. These compounds display a rich electrochemical behavior which is affected b y the nature of the linkers.