Electronic structure and luminescence of antimony (III) halide complexes with N,N′-diphenylguanidine

•The structure of levels contributing to luminescence excitation were determined.•Excitation was similar in energy to the 3a1g → 4t1u and 1t1g → 4t1u transitions.•Transitions with spin inversion are allowed in the double point groups.•Jahn–Teller effect leads to the T1u state splitting into A2u + Eu.

To determine the orbital nature of the excitation for the luminescence of the SbX63−(HDphg)+3 complexes, where X = Cl, Br and HDphg+ is diphenylguanidine, the structure of the valence and core levels was investigated using X-ray photoelectron spectroscopy and density functional theory. The results indicated that the valence bands of the compounds fall into two level systems localised on the anion and cations. HOMO 3a1g2 and LUMO 4t1u on the SbX63− anion, which is responsible for the lower excited state, are antibonding combinations of the Xnpσ group orbitals with Sb 5s and 5p AOs, respectively.

Graphical abstractSeveral anion HOMOs and their location on the experimental XPS spectrum of the (HDрhg)3SbCl6 complex are shown.Figure optionsDownload full-size imageDownload as PowerPoint slide