Electronic structures and spectral properties of the emitting molecule rhenium (I) tricarbonyl containing naphthalimide ring in chemical manufacturing system

Rhenium (1) tricarbonyl complexes comprise an important class of luminescent materials in chemical manufacturing system. A Re(1) complexes, Re(CO)(3)(phen-PIN)(Cl) (1), where PM = 4-piperidinyl-1,8-naphthalimide, was investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The optimized ground structures show that the phen ring is not coplanar with the naphthalimide ring. The HOMO is it character, while the LUMO is pi* orbitals of the phen ligands. The lowest lying absorption band of the complexes has the HOMO -> LUMO+1 transition configurations resulting in the LLCT/ILCT characters