Spontaneous sulfur dioxide activation by Group V metal (V, Nb, Ta) atoms in excess argon at cryogenic temperatures

Abstract

Reactions of laser-ablated V, Nb and Ta atoms with SO2 in excess argon during condensation gave new absorptions in the M=O stretching region, which were assigned to metal sulfide oxides SMO2 and anions SMO2(-) (M = V, Nb, Ta). The metal oxide complex OV(η(2)-SO) was also identified through the V=O and the characteristic side-on coordinated S-O stretching modes. The assignments of major vibrational modes were confirmed by appropriate S(18)O2 and (34)SO2 isotopic shifts, and density functional frequency calculations. DFT calculations were employed to study the behavior of reactions of Group V bare metal atoms with SO2, and a representative profile was derived which not only showed the preferred coordinating fashion of metal atoms but also tracked the path of S-O bond activation. The η(2)-O,O' bridge coordinated complexes are preferred with energy decreases of ca. 50 kcal mol(-1) for all three metals, which facilitate the activation of two S-O bonds in succession and finally direct the reaction to the most stable molecules SMO2 (M = V, Nb, Ta) along the potential energy surface (PES). Finally the SMO2 molecules capture electrons to give anions SMO2(-) with about 3.6 eV electron affinities based on DFT calculations.

Rationalizing the Low‐Spin Products Observed for the Reactions M+CH3CN (M=V, Nb,Ta) Through a Non‐Spin Flip Scheme.

“…Different reactions of laser‐ablated transition metal atoms with small organic molecules have been investigated under matrix‐isolation conditions by IR spectroscopy . The results emerging from these studies point toward new synthesis routes for obtaining high‐oxidation state products, such as those arising from the oxidative addition of the organic molecule to the metal atom, as well as carbene and carbyne compounds.…”

Applying a Nonspin-Flip Reaction Scheme to Explain for the Doublet Sulfide Oxides SMO2 Observed for the Reactions of SO2 with V(4F), Nb(6D), and Ta(4F)

“…Importantly, for most of these reactions, the spin multiplicity assigned to the products does not match the spin corresponding to the ground state of the reactants. For example, the frequencies detected in the IR-matrix spectra for the products emerging from the reactions M + SO 2 (M � V( 4 F), Nb( 6 D), and Ta( 4 F)), mainly the complex OV(η 2 -SO) and the sulfide oxides SMO 2 (M � V, Nb, Ta), fix better those determined through DFT calculations for the corresponding doublet structures [17]. Liu et al rationalized the different spin multiplicity between the reactants and the products by invoking interactions between electronic states of different spin through intersystem-crossings.…”

“…All the located stationary points were characterized as energy minima or transition states through frequency analysis calculations at DFT level of theory. ese calculations were done employing the functional B3LYP as used before by Liu et al in a previous contribution on the investigated interactions for comparing the theoretical frequencies with the experimental ones [17]. Inclusion of a portion of exact exchange from Hartree-Fock theory using a hybrid functional can be important for the comparative description of systems involving electronic states with unpaired electrons, such as the quadruplet and doublets electronic states studied in this contribution.…”

“…Results emerging from those studies show that SO 2 is more reactive than other gases (O 2 , SO 2 , CO 2 , N 2 , N 2 O, and NO) in this kind of reactions [10][11][12][13][14]. e interaction of SO 2 with laser-ablated transition metal atoms in groups IV-VI of the periodic table has been investigated by IR spectroscopy under matrix-isolation conditions [15][16][17]. e main products observed for these interactions are the oxide complex OM(η 2 -SO) and/or the sulfide oxide SMO 2 .…”

A two‐step reaction scheme leading to singlet carbene species that can be detected under matrix conditions for the reaction of Zr(3F) with either CH3F or CH3CN

“…Recently, different reactions for small molecules with laser‐ablated transition‐metal atoms have been investigated under matrix‐isolation conditions by IR spectroscopy . In particular, the product distributions for the reactions of several halomethanes CH 4 − n X n ( n = 1–4; X = F, Cl) and CH 3 CN with atoms belonging to three transition series have been reported .…”