Unconventional H‐bonds: SH···N interaction

Quantum calculations at the MP2/aug‐cc‐pVDZ level are used to analyze the SH···N H‐bond in complexes pairing H 2 S and SH radical with NH 3 , N(CH 3 ) 3 , NH 2 NH 2 , and NH 2 N(CH 3 ) 2 . Complexes form nearly linear H‐bonds in which the SH covalent bond elongates and shifts its stretching frequency to the red. Binding energies vary from 14 kJ/mol for acceptor NH 3 to a maximum of 22 kJ/mol for N(CH 3 ) 3 and N(CH 3 ) 2 NH 2 . Analysis of geometric, vibrational, and electronic data indicate that the SH···N interaction involving SH is slightly stronger than that in which the closed‐shell H 2 S serves as donor. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011