Intramolecular hydrogen bond between aromatic hydrogen and coordinated sulfur atom (sp(2)C-H center dot center dot center dot S)

Weak interaction between the H16 atom of aromatic hydrocarbon and the coord inated S2 atom, a new type of hydrogen bond sp(2) C-H ... S, has been sugge sted in explaining the phenomenon of the H-1 NMR H16 peak of the compound(E t4N)(2)[Pd-2(mp)(2)(Hmp)(2)](H(2)mp = 2-mercaptophenol) appearing at delta 8. 79 which is 1. 7 lower than the expected value delta 7. 1. The distances of C16 ... S2(0. 361 pm) and H16 ... S2(0. 295 pm) lowing the sum of the v an der Waals radii (0. 325 pm) for the corresponding atoms, respectively, d emonstrates the existence of the hydrogen bond. In addition, it has been ob served that the <(nu)over bar>(C-H) of aromatic hydrocarbon shifts to 2 998 cm(-1) resulting from the sp(2) C-H ... S hydrogen interaction. Comparison with the structure of the analogues compound [Pd-2(PPh3)(2) (Hmp)(2)Cl-2] and the remaining of the O-H ... O and C-H ... S hydrogen bonds even in DMS O suggest that the torsion angle between the phenyl linking to the bridging sulfur atom and Pd2S2 plane deviated from 90 degrees may be contributed pa rtially from the C-H ... S hydrogen bonding.