ORGANOTRANSITION-METAL METALLACARBORANES .16. DIRECTED SYNTHESIS OF ARENE-LINKED METAL SANDWICH COMPLEXES VIA CONTROLLED SUBSTITUTION ON BORON

The synthetic utility of the B(5)-alkylation method described in the preceding article was explored via reactions with dihaloalkylarenes to create phenylene-linked bis(metallacarboranyl) complexes, nido-Metallacarboranes of the type (Et2C2B3H5)M(ligand), where M(ligand) = Co(C5Me5), Fe(C6Me6), and Ru(MeC6H4CHMe2), were bridge-deprotonated and treated with xylyl bromides to form xylyl-bridged dimetallic species of the general formula [(ligand)Me(Et2C2B3H4-5-CH2)]2C6H4. Thermal reactions of the iron and ruthenium complexes with (Et2C2B4H4)Fe(η6-C8H10) resulted in η6 coordination of a (Et2C2B4H4)Fe unit to the phenylene ring of each complex, forming trimetallic species in which the central C6 ring serves as a linchpin. A similar reaction of the B-benzyl complex (Et2C2B3H4-5-CH2C6H5)Fe(C6Me6) gave the benzyl-bridged diiron compound 5-[(Et2C2B4H4)Fe(C6H5CH2)]-(Et2C2B3H4)Fe(C6Me6). The new complexes were isolated as air-stable solids in generally high yields and characterized from their11B and1H NMR, infrared, and mass spectra. © 1990, American Chemical Society. All rights reserved.