We have studied the reactivity towards dihydrogen of Ni2+-Ni+ reduced ions, residing above two framework oxygen atoms, using a 18 SiO4 tetrahedrals (18T) model cluster representing the intersection of the straight and the sinusoidal channels in ZSM-5 zeolite. Reported are a detailed analysis of the Ni+-H-2 orbital interactions, the thermodynamic stability, and characteristic spectral signatures of the predicted Ni+(H-2)(n) nonclassical hydrides for n = 1 and 2, at the B3LYP level of theory. Comparison is made to existing spectroscopy data for a Ni+(H-2) complex formed in Ni-exchanged ZSM-5 zeolite [11]. (C) 2012 Elsevier B.V. All rights reserved.