ALUMINUM ATOM-BENZENE MOLECULAR-COMPLEX - MATRIX-ISOLATION ELECTRON-SPIN RESONANCE STUDY

Recently we have shown that the A1 atom (3s2 3p1]) forms a π-coordination complex with ethylene and that the complex results from the dative interaction between the vacant antibonding π orbital of ethylene and the semifilled p orbital of A1 parallel to the double bond.1 We report in this communication the generation and the detection by ESR of the A! atombenzene molecular complex stabilized in neon matrices. The lowest, vacant π orbitals of benzene belong to the irreducible representation e2(doubly degenerate) of the C6v symmetry group. The semifilled p orbital of A1 located along the symmetry axis of benzene would belong to either a1 (pz) or e1 (px and py), and hence cannot effect the dative interaction with the lowest, vacant π orbitals of benzene. One thus anticipates the Al atom-benzene complex to be of symmetry lower than C6v. The present study revealed unequivocally that the Al atom complexes with benzene through only one C=C unit of the ring. © 1979, American Chemical Society. All rights reserved.