Icosahedral carboranes represent an exciting organomimetic cluster platform capable of producing a wide array of tuneable ligand frameworks.1 We recently discovered that 1,1′-bis-o-carborane2 (bc) can be used as a strong-field ancillary ligand in late transition metal complexes that exhibit phosphorescent emission. These complexes constitute a new class of robust and highly efficient emitting molecules for use in organic light emitting diodes (OLEDs).3 To better understand the chemistry of bc as a bidentate scaffold, a series of phosphine ligated complexes M(bc)(dppe) (where M = Ni, Pd, Pt; dppe = 1,2-bis(diphenylphosphino)ethane) were synthesized and fully characterized. Next, two bc-based Pt(II) complexes chelated by 4,4′-di-tert-butyl-2,2′-bipyridine (dtb-bpy) were prepared and were found to display blue phosphorescent emission dominated by a metal-to-ligand charge transfer (MLCT). These findings were reinforced by DFT calculations that indicate a Pt-centered HOMO and (dtb-bpy)-centered LUMO, suggesting the photophysical innocence of bc as a ligand. This study opens a new avenue for designing efficient OLED materials with tunable properties featuring organomimetic boron-rich clusters. References: 1. Spokoyny, A. M. Pure Appl. Chem., 2013, 85, 903-919. 2. Owen, D. A.; Hawthorne, F. M. J. Am. Chem. Soc., 1971, 93, 873-880. 3. Chi, Y.; Chou, P.-T. Chem. Soc. Rev., 2010, 39, 638-655.

Photophysically innocent boron cluster ligand scaffolds for organic light emitting diode materials

251st National Meeting (2016)

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