Cukrowski, IgnacyMatta, Cherif F.2011-02-222011-02-222010-10Cukrowski, I & Matta, CF 2010, 'Hydrogen-hydrogen bonding : a stabilizing interaction in strained chelating rings of metal complexes in aqueous phase', Chemical Physics Letters, vol. 499, no. 1-3, pp. 66-69. [http://www.elsevier.com/locate/cplett]0009-26141873-4448 (online)10.1016/j.cplett.2010.09.013http://hdl.handle.net/2263/15919Two H...H close contacts, classically associated with steric hindrance, were found to be H–H closed-shell bonding interactions which stabilize a zinc(II) complex with nitrilotri-3-propanoic acid, [Zn(NTPA)(H2O)2]–, by ca. 11 kcal/mol in aqueous phase. The strain energy of three 6-member rings (ca. 40 kcal/mol) is significantly offset by these interactions the presence of which is indicated by the presence of a bond path, an elevated delocalization index, and a lowering of the atomic energy of each hydrogen atom involved in an H...H interaction by 4–5 kcal/mol. The difference between relevant bond path angles and geometrical bond angles in the 6-member coordination rings correlates well with strain energy and formation constants. Unexpectedly, the bite angle N–Zn–O is found to be the least strained.en© 2010 Elsevier B.V. All rights reserved.Hydrogen–hydrogen bondingStrain energyH–H bondingFormation constantSteric hindrancePostprint Article