Sulfur Dioxide Activation: A Theoretical Investigation into Dual S═O Bond Cleavage by Three-Coordinate Molybdenum(III) Complexes

Abstract

Cummins et al. have observed that 3 equiv of Mo(N[R]Ar)3 (R = C(CD3)2CH3, Ar = 3,5-C6H3Me2) are required for dual S═O bond cleavage within a SO2 molecule. Using density functional theory calculations, this theoretical study investigates a mechanism for this SO2 cleavage reaction that is mediated by MoL3, where L = NH2 or N[(t)Bu]Ph. Our results indicate that an electron transfers into the SO2 ligand, which leads to Mo oxidation and initiates SO2 coordination along the quartet surface. The antiferromagnetic (AF) nature of the (NH2)3Mo-SO2 adduct accelerates intersystem crossing onto the doublet surface. The first S═O bond cleavage occurs from the resulting doublet adduct and leads to formation of L3Mo═O and SO. Afterward, the released SO molecule is cleaved by the two remaining MoL3, resulting in formation of L3Mo═S and an additional L3Mo═O. This mononuclear mechanism is calculated to be strongly exothermic and proceeds via a small activation barrier, which is in accordance with experimental results. An additional investigation into a binuclear process for this SO2 cleavage reaction was also evaluated. Our results show that the binuclear mechanism is less favorable than that of the mononuclear mechanism.

Soluble Cytotoxic Ruthenium(II) Complexes with 2-Hydrazinopyridine

“…The N-Ru-N bond angles (80.22°-81.48°) are also deviating from (90°). A comparison of the calculated Ru-Cl and Ru-N bond lengths with those of reported Ru(II) complexes involving bidentate N-donor ligands reveals that the average values found for Ru-Cl (2.493 Å) is consistent with the range of the reported values {2.473 (p-cymene)Ru(curcuminato)chloro} [49]. [53].The calculation of atomic charges explains the potential donor and acceptor property of atoms [54].…”

“…The energy minimization studies were carried out using the GAUSSIAN 09W software program. Molecular geometries of the singlet ground state of the complexes were fully optimized in the gas phase at the B3LYP/LanL2DZ basis set [48,49]. The optimized geometries of complexes 1-4 are given in Fig.…”

Cytotoxic study against L20B cell line, spectral characterizations and DFT theoretical calculations for new dioxidovanadium(V) complexes with dinitrogen donor ligands

“…The optimized structures were carried out by using the B3LYP/6-31G(d, p) for the ligands and LanL2DZ for the dioxidovanadium (V) complexes basis set; respectively [27,28]. The complexes structure with natural bond order (NBO) charges of atoms are given in Fig.…”

Experiment and Theory Clarify: Sc+ Receives One Oxygen Atom from SO2 to Form ScO+, which Proves to be a Catalyst for the Hidden Oxygen‐Exchange with SO2

“…In this vein, Armentrout et al., using guided ion beam mass spectrometry, [12] have reported that the activation of the S−O bond of sulfur dioxide by the cations of the heavy transition metals rhenium, [13] osmium, [14] and iridium [15] can only be achieved under endothermic conditions. Naturally, for most of the considerations in this undertaking, the S−O bond activation represents the key issue [16] . Consequently, a better understanding of the SO 2 activation and S−O bond cleavage by transition metals is vital in order to make progress in this field.…”