Reactions of Laser-Ablated Co and Ni Atoms with Nitrogen Atoms and Molecules. Infrared Spectra and DFT Calculations of Metal Nitride Molecular Species and Complexes

Abstract

Laser-ablated Co and Ni atoms, co-deposited with pure nitrogen at 10 K, gave a strong new 795.3 cm -1 band with cobalt and a 838.8, 836.1 cm -1 isotopic doublet (2.5/1.0) with nickel, which exhibited 14/15 isotopic ratios appropriate for the diatomic CoN and NiN molecules. In solid argon, CoN absorbs at 826.5 cm -1 and gives way on annealing to bands at 795.8 and 792.0 cm -1 , which are due to (NN) x CoN complexes. Density functional theory (DFT) calculations predict quintet and quartet ground states for CoN and NiN, respectively, and frequencies in reasonable agreement with the observed values. Evidence is also presented for the dimetal dinitrides, (CoN) 2 and (NiN) 2 , with rhombus structures and metal-metal bonding across the ring. DFTbased calculations and revised assignments are presented for Ni-NN stretching modes in the dinitrogen complexes.

Electronic structures of 3d‐metal mononitrides

“…It seems BH-LYP gives a bond distance comparable to the MRCI study, and the dissociation energy is also close (1.10 eV at our BHLYP calculation, 1.36 eV at MRCI 21 ). However, BHLYP predicts a much lower vibrational frequency (516 cm Ϫ1 ) compared both the experiment (832.4 cm Ϫ1 ) 15 and previous DFT calculation [841(18) cm Ϫ1 ], 14 and extremely small IP (0.07) is obtained compared with the other four methods (Table 3). This indicates that further study in both experiment and advanced theory is necessary for NiN.…”

“…Except at BHLYP (1.797 Å), our calculated bond distances are close to the results of MRSDCIϩQ (1.622 Å), 26 slightly longer than previous DFT (by use of Vosko-Wilk-Husair potential) value (1.588 Å). 14 The pure exchange functional methods BLYP (834 cm…”

“…1 For 3d-metal mononitrides, experimental studies were available only for the neutral species. These include mass-spectrometric investigation on ScN, 2 TiN, 2 and VN; 2 near-infrared electronic emission spectra on ScN; 3 electronic spectra on TiN 4,5 and VN; 6 Stark spectra on TiN; 7 laser spectroscopy on TiN; 8 laser-induced fluorescence on VN 9,10 and CrN; 10,11 laser ablation and matrix infrared techniques on VN, 12 CrN, 12 MnN, 12 FeN, 13 CoN, 14 NiN, 14 and MN (MASc, Ti, V, Cr, Mn, Fe, Co, Ni). 15 Theoretical studies on the neutral species include MRCI (multireference configuration interaction) method on ScN, 16 TiN, 17,18 VN, 18,19 CrN, 18,20 FeN, 21 and NiN; 21 complete active space self-consistent field (CASSCF) on FeN; 20 CIPSI (configuration interaction by perturbation of a multiconfiguration wave function selected iteratively) method on ScN 22 and CuN; 23 CCSD(T) (coupled cluster singles doubles noniterative triples) on MN (MASc, Ti, V, Cr); 24 LDA-LCAO (local density functional linear combination of atomic orbitals) on TiN; 25 DFT (density functional theory) study with B3LYP (explanation see the second part) method on VN, 12 CrN, 12 MnN, 12 and FeN; 13 DFT 14,15 and MRSDCIϩQ (multireference single and double excitation configuration interaction with Davidson-type correction), as well as MRCPA (multireference coupled pair approximation) on CoN.…”

Intrinsic Dinitrogen Activation at Bare Metal Atoms

“…[120] Later studies showed, however, that this assignment is incorrect, and that the complex is more likely to be linear (that is, with end-on coordination of the N 2 ligand). [121] DFT + has been studied in the gas phase by ion cyclotron resonance mass spectrometry. [122] A ligand-substitution reaction (displacement of N 2 by CH 4 ) was used to…”

A high resolution visible spectrum of iridium monophosphide

“…No theoretical literature could be found on CoP or RhP. However, DFT calculations on the lowest singlet, triplet, and quintet states of CoN have been reported by Andrews et al [36], giving 5 D as the ground state. …”