Lithium bond structures of H n Y (n=2, 3; Y=O, S, N)⋯LiNH2 and the abnormal blue shift of N—Li bond

Abstract

The optimized geometries of the complexes between HnY (n=2, 3; Y=O, S, N) and LiNH2 have been calculated at the B3LYP/6-311++G** and MP2/6-311++G** levels. Three stable complexes were obtained. Frequency analysis showed that the enlarged 2N—4Li presents the abnormal blue shift in three complexes. The calculated binding energy with basis set super-position error (BSSE) and zero-point vibrational nergy (ZPE) corrections of complex I–III is −58.65, −31.66 and −69.59 kJ·mol−1 (MP2), respectively. Natural bond orbital theory (NBO) analysis has been performed, and the results revealed that the H2O⋯LiNH2 (complex I) and H3N⋯LiNH2 (complex III) are formed with coexisting σ-s and n-s type lithium bond interactions, complexII is formed with π-s type lithium bond interaction between HnY (n=2,3; Y=O, N) and LiNH2, and H2S⋯LiNH2 (complex II) is formed with n-s type lithium bond interaction between H2S and LiNH2. Natural resonance theory (NRT) and atom in molecule (AIM) theory have also been studied to investigate the bond order and topological properties of the lithium bond structures.