Remarkable Dinitrogen Activation and Cleavage by the Gd Dimer: From Dinitrogen Complexes to Ring and Cage Nitrides

Abstract

Dinitrogen activation and its chemical transformations are one of the most challenging subjects in chemistry. Coordination of N 2 to transition-metal or f-element metal complexes is often an effective strategy for activation because it weakens the s and/or p bonds of N 2 through side-on or end-on coordination. Many dinitrogen complexes exhibit subsequent reactivity at the N 2 unit that can lead to its further activation, complete N À N bond cleavage, and functionalization. [1][2][3] Reactions of metal atoms and small clusters with dinitrogen serve as ideal models for fundamental understanding of the multifaceted mechanisms of dinitrogen activation by d-and fmetal complexes and surfaces.Previous investigations have demonstrated N À N bond cleavage by some transition-metal atoms and dimers. [4, 5] Herein we report a joint matrix-isolation infrared-spectroscopic and theoretical study of the reaction of Gd 2 with N 2 , which proceeds by the initial formation of an unprecedented dinuclear lanthanide dinitrogen complex with a simultaneously side-on and end-on bonded N 2 ligand. The complex isomerizes to a planar cyclic [Gd(m-N) The above-mentioned species were prepared by codeposition of laser-evaporated Gd atoms and clusters with N 2 /Ar mixtures onto a CsI window at 6 K as previously described. [6] Infrared spectra were recorded on a Bruker IFS 66-V spectrometer at 0.5 cm À1 resolution using a liquid-nitrogencooled mercury cadmium telluride (MCT) detector. With relatively high N 2 concentration (0.5 %) and low laser energy (< 5 mJ/pulse), the [Gd(N 2 )] and high-coordinate dinitrogen complexes, which have been previously identified, [7] were produced. The IR spectra in the selected regions with lower N 2 concentration (0.05 %) and higher laser energy (10 mJ/

Mass Spectrometry and Theoretical Investigation of VNn+ (n = 8, 9, and 10) Clusters

“…Jin and co-workers reported the spectroscopic identification of the [B 3 (N 2 ) 3 ] + complex which features the smallest π-aromatic system, B 3 + . Zhou studied the [Gd 2 N 2 ] complex and found remarkable N 2 activation and cleavage by the Gd dimer . In our previous work, the TiN 12 + clusters were generated by laser ablation, the most stable structure of which was found to be Ti­(N 2 ) 6 + with O h symmetry .…”