title: Complexation of n SO2 molecules (n = 1, 2, 3) with formaldehyde and thioformaldehyde.
abstract: Ab initio and density functional theory calculations are used to examine complexes formed between H2CO and H2CS with 1, 2, and 3 molecules of SO2. The nature of the interactions is probed by a variety of means, including electrostatic potentials, natural bond orbital, atoms in molecules, energy decomposition, and electron density redistribution maps. The dimers are relatively strongly bound, with interaction energies exceeding 5 kcal/mol. The structures are cyclic, containing both a O/S⋯S chalcogen bond and a CH⋯O H-bond. Addition of a second SO2 molecule leads to a variety of heterotrimer structures, most of which resemble the original dimer, where the second SO2 molecule engages in a chalcogen bond with the first SO2, and a C⋯O attraction with the H2CX. Some cooperativity is apparent in the trimers and tetramers, with an attractive three-body interaction energy and shortened intermolecular distances.
authors: Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E-28006, Madrid, Spain.
authors: Luis Miguel
authors: LM
authors: Azofra
authors: Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA.
authors: Steve
authors: S
authors: Scheiner
mesh_terms: D019281:Dimerization; D005557:Formaldehyde / Q000031:analogs & derivatives* / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011789:Quantum Theory; D055672:Static Electricity; D013458:Sulfur Dioxide / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: C527773:thioformaldehyde; D013458:Sulfur Dioxide; D005557:Formaldehyde