Reactions of Laser-Ablated Aluminum Atoms with Cyanogen: Matrix Infrared Spectra and Electronic Structure Calculations for Aluminum Isocyanides Al(NC)_1,2,3 and Their Novel Dimers

Abstract

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.

Cyanides, Isocyanides, and Hydrides of Zn, Cd and Hg from Metal Atom and HCN Reactions: Matrix Infrared Spectra and Electronic Structure Calculations

“…Cyanogen generally reacts with metal atoms to form dicyanides or even tetracyanides [10–19] . Our work with the Group 2 metal atoms and HCN or with (CN) 2 provided IR spectra for the MNC isocyanides with no obvious amount of the cyanide isomer MCN [18] .…”

“…[ 9 , 17 ] Infrared (IR) spectra were recorded at 0.5 cm −1 resolution on a FTIR vacuum spectrometer (Bruker Vertex 70v) equipped with a transfer optic and Mid‐IR MCT detector (4000–450 cm −1 ). Matrix samples were annealed at different temperatures and cooled back to 5 K, and selected samples were irradiated in the ultraviolet (UV) by a medium pressure mercury arc street lamp (175 W):[ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ] Observed and calculated vibrational frequencies are reported here in cm −1 units.…”

“…For investigation of novel cyanide and isocyanide molecules with infrared (IR) spectroscopy, we have produced by laser ablation Group 2, 3, 4, 7, 8 and 13 metal atoms as well as the Ce, Nd, Th, and U atoms. We have observed their reactions with cyanogen and U with hydrogen cyanide, and Zn with oxygen and hydrogen mixtures [1–20] …”

“…We have observed their reactions with cyanogen and U with hydrogen cyanide, and Zn with oxygen and hydrogen mixtures. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]…”

“…We have observed their reactions with cyanogen and U with hydrogen cyanide, and Zn with oxygen and hydrogen mixtures. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Cyanogen generally reacts with metal atoms to form dicyanides or even tetracyanides. [10][11][12][13][14][15][16][17][18][19] Our work with the Group 2 metal atoms and HCN or with (CN) 2 provided IR spectra for the MNC isocyanides with no obvious amount of the cyanide isomer MCN.…”