Noncovalent n → π*, C–H⋯π, and C–H⋯O interaction mediated supramolecular assembly in a Re(CO)3(trifluoroacetate) complex bearing a bulky tetraazaphenanthrene ligand: a combined CSD study and theoretical calculations

Abstract

The complex [Re(CO)₃(Ph₄TAP)(OCOCF₃)] where Ph₄TAP is 2,3,6,7-tetraphenyl-1,4,5,8-tetraazaphenanthrene was synthesized, characterized and fully studied by computational approaches. The structural aspects of the complex were compared with similar structures YIBRIL and PODWIR available in the Cambridge Structural database (CSD). The intra- and intermolecular interactions were theoretically determined by QTAIM, non-covalent interaction index-independent gradient model (NCI-IGM), and natural bond orbital (NBO) approaches and compared with similar structures. The complex showed interesting intermolecular n → π* and C–H⋯π interactions which were supported by non-classic C–H⋯O hydrogen bonding, mediating the supramolecular assembly of molecules into two concurrent chains along the b- and c-axes. The molecular structure shows an interesting intramolecular n → π* interaction between the carboxylate group and metal-bound carbonyl ligand and also intramolecular π⋯π* contacts of the equatorial metal-bound carbonyls and the peripheral phenyl rings. Additionally, energy decomposition analysis combined with natural orbital for chemical valence (EDA–NOCV) analysis has been performed to estimate the pairwise interaction energies in the title complex and its dimer associates.