“…[2] In general, these species are highly unstable,and it is of utmost importance to choose aproper ligand to stabilize the metal centers.Since the first isolation and structural characterization of N-heterocy-clic carbenes (NHCs) by Arduengo et al, [3] NHCs have been used as neutral ligands to stabilize radicals and radical ions of main-group elements in low-oxidation states. [9] Al II complexes are typically unstable and readily dimerize or oligomerize with concomitant formation of compounds with Al À Al bonds.T herefore,m onomeric species have only been generated and characterized at low temperatures.Already in 1988, Uhl reported on the tetrasubstituted dialuminum compound [(Me 3 Si) 2 CH] 4 Al 2 , [10] and afterwards,d onor-stabilized dialuminum species of the composition LX 2 AlÀAlX 2 L, including Al 2 X 4 ·2 L(X= Cl, Br,L= NMe 2 (SiMe 3 ); X= I, L = PEt 3 ) [11] and Al 2 Br 4 ·2 MeOPh, [12] were successively isolated. In contrast, stable radical complexes with neutral aluminum centers have not been isolated whereas stable M II (boryl) 2 (M = Ga, In, Tl) radicals have recently been reported by the groups of Aldridge and Jones.…”