Matrix infrared spectra and density functional calculations of transition metal hydrides and dihydrogen complexes

Abstract

Metal hydrides are of considerable importance in chemical synthesis as intermediates in catalytic hydrogenation reactions. Transition metal atoms react with dihydrogen to produce metal dihydrides or dihydrogen complexes and these may be trapped in solid matrix samples for infrared spectroscopic study. The MH(2) or M(H(2)) molecules so formed react further to form higher MH(4), (H(2))MH(2), or M(H(2))(2), and MH(6), (H(2))(2)MH(2), or M(H(2))(3) hydrides or complexes depending on the metal. In this critical review these transition metal and dihydrogen reaction products are surveyed for Groups 3 though 12 and the contrasting behaviour in Groups 6 and 10 is discussed. Minimum energy structures and vibrational frequencies predicted by Density Functional Theory agree with the experimental results, strongly supporting the identification of novel binary transition metal hydride species, which the matrix-isolation method is well-suited to investigate. 104 references are cited.

Mercury Is a Transition Metal: The First Experimental Evidence for HgF4

“…Mercury atoms were evaporated from a stainless steel reservoir at 55 8C through a stainless steel valve (Nupro SS4BK), as described previously, [34,35] into neon (or argon) and fluorine condensing onto a cesium iodide window at 4 K. [36] IR spectra were recorded on a Nicolet 750 instrument at 0.5 cm À1 resolution. Samples were irradiated by a mercury arc street lamp (Sylvania H39 KB-175) with the outer globe removed.…”

Reactions of Th and U Atoms with C2H2: Infrared Spectra and Relativistic Calculations of the Metallacyclopropene, Actinide Insertion, and Ethynyl Products

“…[4, 9,38] The Nd/YAG laser fundamental (1064 nm, 10 Hz repetition rate, 10 ns pulse width) was focused on rotating actinide metal target (Oak Ridge National Laboratory) using 5-20 mJ per pulse. Laser-ablated actinide atoms were co-deposited with C 2 H 2 (typically 0.25 %) in excess argon onto a 7 K CsI window at 2-3 mmol for one hour.…”

Investigation of Gold Fluorides and Noble Gas Complexes by Matrix‐Isolation Spectroscopy and Quantum‐Chemical Calculations

“…[35] However, AuH 2 has been characterized by matrix IR spectra and electronic structure computations. [36] Herein we report IR spectra and quantum-chemical calculations of the products of laser-ablated gold atom reactions with fluorine in excess argon and neon during condensation at 4 K. New gold fluoride species were prepared by co-deposition of gold atoms with F 2 /Ne or F 2 /Ar mixtures onto a CsI window at 4 K [37][38][39] in Virginia and Freiburg. IR spectra in the AuÀF stretching frequency region produced by Au atom reactions with 3, 6, 12, and 24 % F 2 in argon are shown in Figure 1.…”