The dimers formed by formic acid (FA) and furan are investigated by ab initio methods and matrix isolation spectroscopy. Nine complexes with binding energies between -3.91 and -0.82 kcal/mol (MP2/6-311++G(d,p) + ZPE + BSSE) are identified. Another five weaker bound complexes are localized at lower level of theory only. The binding in the furan-FA dimers can be described in terms of OH...O, C=O...H, HO...H, CH...O, OH...pi, and CH...pi interactions. Therefore, the furan-FA complexes are classified in two types: (1) the dimers where the OH hydrogen of formic acid interacts with the furan molecule and (2) the dimers where the main interactions of FA with the furan molecule are via the less acidic CH hydrogen. Duning's and Pople's triple and double basis sets were used to study the dependence of the geometries and energies of the complexes from the basis set. BSSE (basis set superposition error) counterpoise corrections (CP) were included during the geometry optimizations of all dimers at the MP2/6-31G(d,p) level of theory. Matrix isolation spectroscopy allowed us to record the IR spectrum of aggregates between FA and furan. By comparison of the experimental IR spectrum with calculated IR spectra of a variety of complexes, it was possible to identify the most stable furan-FA dimer as the major product of the aggregation.

The complexes formed by noncovalent interactions between formic acid and dimethyl ether are investigated by ab initio methods and characterized by matrix isolation spectroscopy. Six complexes with binding energies between -2.26 and -7.97 kcal mol(-1) (MP2/cc-pVTZ+zero point vibrational energy+basis set superposition erros) are identified. The two strongest bound complexes are, within a range of 0.3 kcal mol(-1), isoenergetic. The binding in these six dimers can be described in terms of OH...O, C=O...H, C-O...H and CH...O interactions. Matrix isolation spectroscopy allowed to characterize the two strongest bound complexes by their infrared spectra.

(Difluoro)methoxyoxo iodine(V) (IF2(O)OCH3), the methyl ester of the unknown difluoro iodic acid (IF2(O)OH), was obtained by the reaction of methoxytrimethyl silane with iodine pentafluoride. IF2(O)OCH3 crystallizes orthorhombic in the space group Pbca with a = 7.605(1) A, b = 7.360(1) A, c = 15.017(1) A, and eight formula units per unit cell. The final R indices [I > 2 sigma(I)] are R1 = 0.0264 and wR2 = 0.0516. Additionally, IF2(O)OCH3 was characterized by its vibrational spectra and quantum mechanical calculations were performed.

In the title compound, [Sn2(CH3)4(C3H6)Cl2]·C2H6OS, the single di­methyl sulfoxide (DMSO) mol­ecule bridges the two Sn atoms via its O atom [Sn—O distances: 2.578 (2) and 2.632 (2) Å], so that each Sn atom displays distorted trigonal‐bipyramidal geometry. The S atom is disordered over two positions with occupancy factors 0.596 (2) and 0.404 (2).