Infrared Spectra and Electronic Structure Calculations for NN Complexes with U, UN, and NUN in Solid Argon, Neon, and Nitrogen

Abstract

Reactions of laser-ablated U atoms with N2 molecules upon codeposition in excess argon or neon at 4 K gave intense NUN and weak UN absorptions. Annealing produced progressions of new absorptions for the UN2(N2)1,2,3,4,5 and UN(N2)1,2,3,4,5,6 complexes. The neon-to-argon matrix shift decreases with increasing NN ligation and therefore the number of noble gas atoms left in the primary coordination sphere around the NUN molecule. Small matrix shifts are observed when the secondary coordination layers around the primary UN2(N2)1,2,3,4,5 and UN(N2)1,2,3,4,5,6 complexes are changed from neon-to-argon to nitrogen. Electronic structure, energy, and frequency calculations provide support for the identification of these complexes and the characterization of the N≡U≡N and U≡N core molecules as terminal uranium nitrides. Codeposition of U with pure nitrogen produced the saturated U(NN)7 complex, which UV irradiation converted to the NUN(NN)5 complex with slightly lower frequencies than found in solid argon.

Study of the histidine complex of uranium(IV): synthesis, spectrophotometric, magnetic and electrochemical properties

“…The complex absorbs maximum at the wavelengths 653 and 663 nm in the visible region. The metal to oxygen and metal to nitrogen coordination has been justified by our IR data and the previous studies [12,[19][20]. The novel compound has paramagnetic nature with two unpaired electrons.…”

“…The different modes of vibrations of the existing COO group in the complex gave rise to the peaks at 736, 659, and 561 cm 1 , which may correspond to its wagging, bending and rocking. The peaks at around 530 and 441 cm 1 may lead to coordinating sites such as oxygen and nitrogen; MO and MN, respectively [12,[19][20]. The peak at high energy (530 cm 1 ) may correspond to U-O coordination if we consider the electronegativity, availability of lone pair of electrons and opposite charges on uranium(IV) and oxygen ions that form strong bonding as compared to U-N.…”

Ti(N5)4 as a Potential Nitrogen-Rich Stable High-Energy Density Material

“…[11][12][13][14][15][16][17][18] Laser ablation methods have often been used to synthesize MN n species using N 2 as a nitrogen source after theoretical predictions. [34][35][36][37][38][39][40][41][42][43][44] For Sc and group 4 metals (Ti, Zr, Hf) considered in this paper, several MN n species including TiN 12 have been observed. [39][40]44 Considering a large formation energy of Ti(N 5 ) 4 using N 2 as a reactant (Table 2), however, a direct synthesis from Ti and N 2 appears rather difficult.…”

Reactions of Group V Metal Atoms with Hydrogen Sulfide: Argon Matrix Infrared Spectra and Theoretical Calculations

“…Our experimental method has been described in detail previously [32][33][34]. Briefly, a Nd:YAG laser fundamental (1064 nm, 10 Hz repetition rate with 10 ns pulse width) was focused onto a rotating transition metal target through a hole in a CsI window cooled normally to 4 K by means of a closed-cycle helium refrigerator.…”