A quantum-chemical study of the possibility to synthesize nuclear spin isomers of water by homogeneous catalytic hydrogenation of compounds containing semipolar X → O bonds (X = N, P, S) with hydrogen

The mechanism of catalytic hydrogenation of compounds with semipolar bonds R n X → O (R n X = N 2 , Me 2 S, C 5 H 5 N, and Ph 3 P) on the (Ph 3 P) 3 RhCl Wilkinson catalyst with para -hydrogen was modeled quantum-chemically by the density functional theory method with the gradient-corrected nonempirically constructed PBE functional and the TZ2 p basis set. The reaction was shown to involve a reaction channel in which the sequential transfer of two hydrogen atoms to oxygen occurred intramolecularly in the coordination sphere of rhodium with the conservation of the spin correlation of protons. This opens up the possibility in principle of using this reaction to prepare para -H 2 O, one of the nuclear spin isomers of water in which proton spins are antiparallel.