Density Functional Theory Studies on Sulfur−Nitrogen Species

Abstract

Density functional theory (DFT) calculations on SNS, S 2 N 2 , and S 4 N 2 are reported. Both local and gradientcorrected nonlocal density functionals are used with moderate and large basis sets. The relative energies, structural parameters, and vibrational frequencies are reported for each molecule and compared with the experimental and theoretical data available in the literature. For S 2 N 2 , DFT results predicted the order of stability of the three low-energy structures as linear chain < pairwise ring < alternate ring in contrast to the MP2 results but in agreement with MRCI results. For S 4 N 2 the order of stability is found to be (1,3) isomer < twisted form of (1,4) isomer < chair form of (1,4) isomer. We discuss identification of experimentally observed infrared absorption peaks of S 2 N 2 and S 4 N 2 .

Vibrational Properties of the Disulfur Dinitride Molecule, S2N2: IR and Raman Spectra of the Matrix-Isolated Molecule

“…The six vibrational fundamentals of such a molecule span the representation 2a g + 1b 1g + 1b 1u + 1b 2u + 1b 3u , with three of these modes (2a g + 1b 1g ) being active only in Raman scattering and the other three (1b 1u + 1b 2u + 1b 3u ) active only in IR absorption. CASPT2 and PBE0 methods have been used to calculate the harmonic vibrational frequencies and IR/Raman intensities listed in Table , which also includes other estimates of the frequencies based on independent DFT calculations. , …”

New Polymers Possessing a Disulfide Bond in a Unique Environment

“…The first inorganic, electrically conducting polymer was polythiazyl, and it was first synthesized in 1953 (Figure ). − In fact, polythiazyl is the only known undoped polymer that is superconducting at low temperatures. , Polythiazyl is composed entirely of sulfur and nitrogen arranged in an alternating pattern which does not allow its electrical properties to be readily changed by varying its molecular structure. In contrast, the physical and chemical properties of electrically conducting polymers based on organic functional groups (i.e., polythiophene and polyaniline) can be varied by the addition of functional groups along the polymeric backbone.…”

Polymerization of Aniline Derivatives to Yield Poly[N,N-(phenylamino)disulfides] as Polymeric Auxochromes

“…An important example of a polymer based on N–S bonds is poly­(sulfur nitride), which is also known as polythiazyl, that was first characterized in 1953 (Figure a). − This polymer is composed entirely of alternating N and S atoms and is referred to as a metallic polymer due to its high electrical conductivity. A limitation of polythiazyl is its simplicity, its structure does not lend the polymer to systematic variation because it is only composed of alternating S and N atoms.…”