Abstract
<jats:p>Spectroscopic investigation of tellurium-centered hydrogen bonds is relatively scarce. Here, 1:1 complex of dimethyl ditelluride (Me2Te2) and H2S was investigated using matrix isolation infrared spectroscopy and quantum chemical calculations. Only S-H路路路Te hydrogen-bond (HB) were identified in argon matrix, evident from pronounced 饾湀spectral shifts. Quantum chemical calculations predicted the S-H路路路Te HB to be significantly stronger than S路路路Te chalcogen-bond (ChB), in spite of very low electronegativity of Te (2.10, Pauling scale). In fact, S-H路路路Te HB in Me2Te2-H2S was found to be as strong as O-H路路路O HB in water dimer. When compared against H2Te-H2S, the smallest binary complex capable of forming an intermolecular S-H路路路Te HB and S路路路Te ChB, the absolute as well as relative strengths of the two noncovalent interactions were found to be systematically increased by two factors (i) methyl substitution in the acceptor moiety and (ii) incorporation of a dichalcogenide bridge. The same two modifications were found to have similar effects for S and Se, too. Increasing methyl substitution was found to increase the proton affinity of the acceptor moiety resulting in shorter HB and larger 饾湀spectral shifts, indicating stronger HB.</jats:p>