Matrix-Isolation and ab Initio Study of HNgCCF and HCCNgF Molecules (Ng = Ar, Kr, and Xe)

Abstract

We report three new noble-gas molecules prepared in low-temperature Kr and Xe matrices from the HCCF precursor by UV photolysis and thermal annealing. The identified molecules are two noble-gas hydrides HNgCCF (Ng ) Kr and Xe) and a molecule of another type, HCCKrF. These molecules are assigned with the help of ab initio calculations. All strong absorptions predicted by theory are found in experiments with proper deuteration shifts. The experiments and theory suggest a higher stability against dissociation of HNgCCF molecules compared to HNgCCH reported previously. Surprisingly, only very tentative traces of HCCXeF, which is computationally very stable, are found in experiments. No strong evidence of similar argon compounds is found here.

Infrared spectrum of elusive C2F radical: A matrix-isolation and computational study

“…Upon annealing at ca. 30 K of a photolyzed HCCF/Kr matrix bands at 1051, 1384, and 2177 cm À1 are observed, which have recently been assigned to HKrCCF molecule [15]. The HKrCCF formation is accompanied by a decrease of the mid-IR bands connected here to C 2 F, which supports the assignment.…”

“…One photolysis product, which has not been identified to our knowledge, exhibits a strong structured absorption around 1600 cm À1 [15]. The absorption band observed in an Ar matrix in this region has components at 1585, 1595 (not well resolved), 1601, 1660 (broad), and 1680 cm À1 .…”

“…The as-deposited matrices contain mainly monomeric HCCF (DCCF) [15], and the band assignment is straightforward using the gas-phase data [17,18]. Some amounts of acetylene, water, CO 2 , and CHF 3 are present in the matrices as an impurity.…”

“…For instance, photolysis of acetylene in noble-gas matrices yields C 2 H radicals [12] and photolysis of HC 3 N produces C 3 N radicals [13]. Radicals with high electronegativity (Y) can form noble-gas (Ng) hydrides HNgY in the H + Ng + Y reaction [14], which explains our special interest to C 2 F that is the precursor for HNgCCF molecules [15]. The experimental results constitute a basis of the present research supported by high-level computational methods.…”

Matrix-isolation and theoretical study of the HXeCCXeH⋯HCCH and HXeCC⋯HCCH complexes

“…The rst noble-gas hydrides were prepared in low-temperature matrices by Pettersson et al in 1995 (ref. 1) and, by now, more than 30 compounds of this type have already been reported, [2][3][4][5][6][7][8] including an argon molecule HArF. 9 We can also mention the preparation and identication of organokrypton (HKrCCH and HKrC 4 H) 10,11 and organoxenon (HXeCCH, HXeCC, HXeCCXeH and HXeC 4 H) [11][12][13] hydrides.…”