Multiple Weak C–H Intramolecular Hydrogen Bonding as an Aid to Minimizing Bond Rotation Flexibility

Abstract

The presence of 14 intramolecular interactions relevant to bond rotational flexibility in coordination compounds important in the context of crystal engineering were identified by density functional theory calculations in the crystal structure of the highly crystalline oxoimido complex [Mo(NC6H4CMe3-2)(O)Cl2(bipy)] (1). A combination of computational techniques including noncovalent interaction index properties and Quantum Theory of Atoms analysis which are based on the computed electron density as well as natural bond orbitals analysis, were used to uncover the nature of the interactions. Weakly stabilizing intramolecular interactions involving electrostatic contributions were found for O····HC, N····HC, and CH····HC, close separations involving the bipy ligand where coordination does not allow flexibility and for O····HC, N····HC, Cl····HC, CH····HC, and C····HC close contacts where C–N and C–C rotations of the imido ligand would allow flexibility. Partial covalency is not a significant feature of these...