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

Abstract

Zinc and cadmium atoms from laser ablation of the metals and mercury atoms ablated from a dental amalgam target react with HCN in excess argon during deposition at 5 K to form the MCN and MNC molecules and CN radicals. UV irradiation decreases the higher energy ZnNC isomer in favor of the lower energy ZnCN product. Cadmium and mercury atoms produce analogous MCN primary molecules. Laser ablation of metals also produces plume radiation which initiates H-atom detachment from HCN. The freed H atom can add to CN radical to produce the HNC isomer. The argon matrix also traps the higher energy but more intensely absorbing isocyanide molecules. Further reactions with H atoms generate HMCN and HMNC hydrides, which can be observed by virtue of their CÀ N stretches and intense MÀ H stretches. Computational modeling of IR spectra and relative energies guides the identification of reaction products by providing generally reliable frequency differences within the Zn, Cd and Hg family of products, and estimating isotopic shifts using to 13 C and 15 N isotopic substitution for comparison with experimental data.

Matrix Infrared Spectroscopic Studies of B-NCCN, B-η2-(NC)-CN, NCBCN, CNBCN, CNBNC, and High-Order Products Produced in Reactions of Boron Atoms with Cyanogen

“…Bands labeled * at 2294.9 and 2053.7 cm –1 are due to the cyanogen isomer CNCN from laser ablation photolysis of the NCCN precursor . Several sets of product absorptions (marked 1 – 9 ) were grouped through their concerted intensity variation on photolysis and annealing.…”

“…Bands labeled * at 2294.9 and 2053.7 cm −1 are due to the cyanogen isomer CNCN from laser ablation photolysis of the NCCN precursor. 40 Several sets of product absorptions (marked 1−9) were grouped through their concerted intensity variation on photolysis and annealing. The relatively broad, strong product absorptions marked "1" in the original deposition spectra dramatically increased on initial annealing to 20 K, but they disappeared on full arc irradiation (λ > 220 nm).…”

Boron-Mediated C–C and C≡N Bond Cleavage of Acetonitrile: Matrix Infrared Spectra and Theoretical Calculations

“…Interactions between metal atoms and the electron-rich N moiety have been intensively investigated both experimentally and theoretically. − The nitrogen end of acetonitrile is long known as an effective electron donor, which can easily coordinate to Lewis acids to form various adducts. − It is now well established from a variety of studies that transition-metal atoms easily react with acetonitrile to generate the end-on, side-on, insertion, methylidene, and methylidyne complexes [M←NCCH 3 , M-η 2 -(NC)-CH 3 , CN–M–CH 3 , CN­(H)­MCH 2 , and CN­(H) 2 MCH] in excess argon. − Boron atom reactions with the CN moiety have been studied in a solid argon matrix, and infrared spectra of BNC, BCN, HBCN, and HBNC have been observed in reactions of boron with HCN, and BNCCN, B-η 2 -(NC)-CN, NCBCN, CNBCN, CNBNC, and high-order products have been observed in reactions with cyanogen, as shown in Scheme . Note: only mono boron atom reactions with nitriles and the CN moiety have been studied.…”