IR Spectroscopy and Density Functional Theory of Small V⁺(N₂)_n Complexes

Abstract

V+(N2)n clusters are generated in a pulsed nozzle laser vaporization source. Clusters in the size range of n = 3-7 are mass selected and investigated via infrared photodissociation spectroscopy in the N-N stretch region. The IR forbidden N-N stretch of free nitrogen becomes strongly IR active when the molecule is bound to the metal ion. Photodissociation proceeds through the elimination of intact N2 molecules for all cluster sizes, and the fragmentation patterns reveal the coordination number of V+ to be six. The dissociation process is enhanced on vibrational resonances and the IR spectrum is obtained by monitoring the fragmentation yield as a function of wavelength. Vibrational bands are red-shifted with respect to the free nitrogen N-N stretch, in the same way seen for the C-O stretch in transition metal carbonyls. Comparisons between the measured IR spectra and the predictions of density functional theory provide new insight into the structure and bonding of these metal ion complexes.

Octa-coordinated alkaline earth metal–dinitrogen complexes M(N2)8 (M=Ca, Sr, Ba)

“…Homoleptic dinitrogen complexes of genuine transition metals, such as tetra-coordinated Ni(N 2 ) 4 , hexa-coordinated vanadium, and chromium complexes M(N 2 ) 6 , have been synthesized and spectroscopically characterized in low-temperature matrices 6–9 . Mass spectrometric and infrared photodissociation spectroscopic investigations in the gas phase revealed that the Ti + , V + , and Nb + cations form six-coordinated dinitrogen complexes 10–12 , while the Y + , La + , and Ce + cations gave the octa-coordinated dinitrogen complexes 13 . There is only one theoretical report on neutral octa-coordinated dinitrogen complexes by Kovacs, who calculated the lanthanum species La(N 2 ) n ( n = 1–8) 14 .…”

Structural evolution of LiNn+ (n = 2, 4, 6, 8, and 10) clusters: mass spectrometry and theoretical calculations

“…Nb + (N 2 ) n and V + (N 2 ) n complexes were investigated using photodissociation spectroscopy. 28,29 Rh(N 2 ) 4 + complexes were studied by infrared laser photodissociation spectroscopy and theoretical calculations. 30 TiN 12 + was generated by laser ablation, and the most stable structure was found to be Ti(N 2 ) 6 + with O h symmetry.…”

Experimental observation of TiN12+ cluster and theoretical investigation of its stable and metastable isomers

“…Duncan and co-workers investigated In–N 2 and Al–N 2 complexes by photoionization spectroscopy, 16,17 and studied Mg + –N 2 , Ca + –N 2 , Nb + (N 2 ) n , and V + (N 2 ) n complexes using photodissociation spectroscopy. 18–21 Dagdigian and co-workers studied the electronic states of an Al–N 2 complex with laser-induced fluorescence spectroscopy. 22 …”