PALLADIUM(II) COMPLEX WITH TETRAHYDROBENZOXAZINOBENZOXOSINE: SYNTHESIS, ELECTRONIC AND MOLECULAR STRUCTURES.

Interaction of the palladium(II) benzonitrile complex [Pd(PhCN)2Cl2] with glyoxal-bis(2-hydroxy-3,5-di-tert-butylphenyl)imine (H2L) induces intramolecular rearrangement of H2L into the corresponding tetrahydrobenzoxazinobenzoxosine (L′), and the coordination of the latter to Pd(II) leads to the formation of [Pd(L′)Cl2]·(CH3)2CO (1·(CH3)2CO). The crystal structure of this compound is determined by XRD. The Pd atom in the structure occurs in a square planar environment of two Cl atoms and two N atoms of the L′ ligand. Quantum chemical calculations within the density functional theory are conducted; the electronic structure of 1 is studied. The Pd–N and Pd–Cl bonds are shown to be intermediate type bonds. Orbitals of N–Pd–Cl three-center bonds are discovered using the NBO analysis. The formation of such three-center bonds can be represented as a result of the electron density donation from the orbitals of nitrogen lone pairs to the σ* orbitals of Pd–Cl bonds. [ABSTRACT FROM AUTHOR]