Calculations of hydrogen-bond-transmitted indirect nuclear spin–spin couplings: a comparison of density-functional and ab initio methods

Abstract

Hydrogen-bond-transmitted indirect nuclear spin–spin coupling constants have been calculated by linear-response density-functional theory (DFT), coupled-cluster singles-and-doubles (CCSD) theory, and multiconfigurational self-consistent field (MCSCF) theory so as to benchmark the performance of DFT against the high-level ab initio methods. The systems under study are (NH 3) 2, (H 2O) 2, and (HF) 2 and their charged counterparts N 2H 7 +, H 5O 2 +, and FHF −. In all cases, the 1 h J (XH) coupling through the X–H⋯Y hydrogen bond changes sign in the transition from the neutral to charged complex. As for intramolecular coupling constants, description of 1 h J (YH) and 2 h J (XY) by DFT deteriorates with an increasing number of lone pairs on the coupled nuclei.