Shift of proton magnetic shielding in ClH ··· Y dimers (Y = N₂, CO, BF)

Abstract

The change in the proton magnetic shielding constant of ClH on the formation of the linear hydrogen-bonded ClH · · · Y (Y = N₂, CO, BF) complexes was determined by GIAO ab initio computations at the B3LYP/aug-cc-pVQZ level of theory. The characteristic downfield shift of the isotropic proton magnetic resonance in the vibrationally red-shifted complexes (ClH · · · N₂, ClH · · · CO and ClH · · · BF) is significantly larger than in the blue-shifted complexes (ClH · · · OC and ClH · · · FB). These results are rationalized by considering the changes in the magnetic and electric contributions to the proton shielding in ClH.

Acknowledgement

The authors wish to acknowledge the financial support of the Engineering and Physical Sciences Research Council (EPSRC) through a Visiting Fellowship (EP/C517792) for SACM to the University of Cambridge.