Reactions of Laser-Ablated Aluminum Atoms with Cyanogen: Matrix Infrared Spectra and Electronic Structure Calculations for Aluminum Isocyanides Al(NC) and Their Novel Dimers.

Laser-ablated Al atoms react with (CN) in excess argon during condensation at 4 K to produce AlNC, Al(NC), and Al(NC), which were computed (B3LYP) to be 27, 16, and 28 kJ/mol lower in energy, respectively, than their cyanide counterparts. Irradiation at 220-580 nm increased absorptions for the above molecules and the very stable Al(NC) anion. Annealing to 30, 35, and 40 K allowed for diffusion and reaction of trapped species and produced new bands for the Al(NC) dimers including a rhombic ring core (C)(AlN)(C) with C's attached to the N's, a (NC)Al(II)-Al(II)(NC) dimer with a computed Al-Al length of 2.557 Å, and the dibridged Al(NC) molecule with a calculated D structure and rhombic ring core like AlH. In contrast, the Al(NC) anion was destroyed on annealing presumably due to neutralization by Al. B3LYP calculations also show that aluminum chlorides form the analogous molecules and dimers. In our search for possible new products, we calculated Al(NC) and found it to be a stable molecule, but it was not detected here.