Valery N. Kozhevnikov

Green-blue light-emitting platinum(ii) complexes of cyclometallated 4,6-difluoro-1,3-dipyridylbenzenes showing mesophase organisation

Blue-green light-emitting phosphorescent PtII complexes of 1,3-bis(2-pyridyl)benzene are reported that incorporate hexadecyl-containing fragments in the 5-position of the pyridine rings. Along with the more classical half disc-shaped hexacatenar molecule with six pendant alkoxy chains, which shows an Rm mesophase, the simpler complex functionalised by just two alkoxy chains, one at each pyridyl 5-position, was also found to be mesomorphic. The luminescence of pure films obtained from these complexes is orange-red, dominated by the excimer-like emission, and is independent of the thermal history of the film. The mesophases of the complexes are three-dimensional and columnar in nature – all are based on a two-dimensional hexagonal arrangement extended into the third dimension.

Pyridazine-bridged cationic diiridium complexes as potential dual-mode bioimaging probes

A novel cell permeable, mitochondria localising, diiridium complex has a high emission yield and two heavy atoms to increase scattering of electrons, supporting potential future applications as a dual fluorescence and electron microscopy probe.

1,2,4-Triazines in the Synthesis of Bipyridine Bisphenolate ONNO Ligands and Their Highly Luminescent Tetradentate Pt(II) Complexes for Solution-Processable OLEDs

This article describes a convenient method for the synthesis of ONNO-type tetradentate 6,6-bis(2-phenoxy)-2,2-bipyridine (bipyridine bisphenolate, BpyBph) ligands and their platinum(II) complexes. The methodology includes the synthesis of 1,2,4-triazine precursors followed by their transformation to functionalized pyridines by the Boger reaction. Two complementary routes employing 3,3- and 5,5-bis-triazines allow a modification of the central pyridine rings in different positions, which was exemplified by the introduction of cyclopentene rings. The new ligands were used to prepare highly luminescent ONNO-type Pt(II) complexes. The position of the cyclopentene rings significantly influences the solubility and photophysical properties of these complexes. Derivatives with closely positioned cyclopentene rings are soluble in organic solvents and proved to be the best candidate for solution-processable organic light-emitting devices (OLEDs), showing efficient single-dopant candlelight electroluminescence.

CCDC 1421707: Experimental Crystal Structure Determination

Related Article: Valery N. Kozhevnikov , Dmitry N. Kozhevnikov , Tatiana V. Nikitina , Vladimir L. Rusinov , Oleg N. Chupakhin , Manfred Zabel , Burkhard Konig|2003|J.Org.Chem.|68|2882|doi:10.1021/jo0267955