Simplified models (model A: [(PhNCH2CH2)(3)N]Mo; model B: [(PhNCH2CH2)(3)N]Mo-N-2) based on triamidoamine complexes were proposed to evaluate the electrostatic/orbital effects of the phenyl rings oil complexation and reduction of N-2. The effect of systematic synchronized rotations (from 0, to 90,) of phenyl dihedral angles on the charge and/or orbital contribution of molybdenum to complex N-2 was studied by chemical descriptors like electrophilicity index (omega) and Mulliken charges. According with the results, there is a favorable modulation of the energy gap of interaction between HOMO/SOMOmodelA and LUMO/LUMO+1(N2) corresponding to pi-back-donation interaction. It is confirmed that phenyl rings not only work as steric walls but also affect the orbital interactions. In accordance with omega values, Model A behaves as nucleophile with respect to N-2. This observation is in agreement with the suggestion that back-donation governs the complex-N-2 interaction. The rotation of dihedral angles of model B also has an effect on the electrophilicity index, allowing modulation in reductive processes. Inductive effects were also assessed by the substituents CN, Br and NH2 in para position on the phenyl rings. The best scenario for N-2 complexation and activation was obtained with [(p-NH(2)PhenylNCH(2)CH(2))(3)N]Mo. The Density Functional Theory was used as theoretical framework. (C) 2009 Elsevier B.V. All rights reserved.