Theoretical Study on Neutral Molecules with Square Planar Tetracoordinate Oxygen O(B)4 Arrangements

As we know, oxygen usually forms two single bonds with other atoms, whereas in this work, we reported the neutral molecules with square planar O(B)4-type tetracoordinate oxygen substructures. The difficulty to achieve a square planar O(B)4-type arrangement is not only to overcome the strain from the planar to tetrahedral configuration but also to constrain it in a right system with the proper symmetry. Several neutral molecules with square planar O(B)4-type arrangements have been studied using the DFT method at the B3LYP/6-311++G(3df,3pd) level of theory. The computational results show that they are all real minima on potential energy hypersurfaces. Thus, it has been shown theoretically that the square planar O(B)4-type arrangement is achieved. The molecular orbitals among the square planar O(B)4-type substructure at D ₂ symmetry have been suggested. Using the molecular orbitals, it has been explained that the oxygen 2p -π electrons in the square planar O(B)4-type arrangement are no longer the lone-pair electrons.