Search

Multilevel oligomers, gradually increasing in size, were generated systematically by using the tetradecker sandwich reaction where double-decker cobaltacarborane aminos are sandwich-complexed to a central metal ion to develop a stable trimetallic complex. This reaction was employed in the case of double-ended bis(cobaltacarborane) anionic complexes. The stagewise building of air-stable multisandwich oligomers and polymers that are soluble in organic solvents can be facilitated by using the appropriate synthons such as bis(cobaltacarborane) complexes bridged by fulvalene or 1,4-bis(tetramethylcyclopentadienyl).

The formation and characterization of the tetracarbon metallacarborane clusters Cp*2Co2Et4C4B6H4X2 were reported. These carbon-rich compounds have an open Co2C4B6 12-vertex cage structure that is a fragment of a 16-vertex Td closo polyhedron. It was shown by X-ray crystallography that the dimer (Cp*Co(Et2C2B3H3))2 have an edge-fused structure. The implications of the formation and structures of the fused and partially fused products are discussed in terms of multidecker stacking mechanisms and skeletal electron-counting theory.

The double-decker stacking reactions of the bridge-deprotonated Cp*Co(2,3-Et2C2B3H3-5-X)1- complexes, where X = Cl, Br, CH3, C(O)CH3, CH2C-triple bond-CCH3 or H and Cp* = eta5-C5Me5, with cobalt(II) and nickel(II) halides in THF yield the diamagnetic Co(III)-Ni(IV)-Co(III) complexes (Cp*Co(2,3-Et2C2B3H2-5-X))2Ni and the paramagnetic Co(III)-Co(IV)-Co(III) complexes (Cp*Co(2,3-Et2C2B3H2-5-X))2Co. These reactions involve the metal complexation of the double-decker substrates and the workup on silica in air.

Cyclic voltammetry, NMR and ESR spectroscopy were used in the study of the electrochemical behavior of the ferracarborane clusters Cp*FeIIH(Et2C2B4H4) andCp*FeIII(Et2C2B4H4) and the phenylene-linked diiron species (Et2C2B4H4)FeIIH(C5Me4-C6H4-C5Me4)FeIII(Et2C2B4H4), ((Et2C2B4H4)FeH(C5Me4))2C6H4 and ((Et2C2B4H4)FeIII(C5Me4))2C6H4. Results showedthe importance of the R2C2B4H4(super 2-) ligands as organometallic synthetic agents and as mono- and dimetallic complex electronic stabilizers.

Illustrates a synthetic approach to a two-dimensional grid polymer. Requirements for the synthesis; Polymerization; Analytical techniques for local structure; Results of linear coupling of carboranyl terminals; Description of connector structure; Tentacle attachment and removal; Infrared spectra of the connectors.