Luminescence Behavior & Photochemistry of Organotransition Metal Compounds

Abstract

In this article, the luminescence and photochemical properties of a selection of organotransition metal compounds are reviewed and discussed. The examples are classified according to the identity of the carbon‐containing ligands, which include the carbonyl, isocyanide, cyanide, alkynyl, alkenyl, arene, aryl, alkylidene, alkylidyne, cyclometalating, and alkyl ligands. The luminescence and photochemistry of selected tungsten, molybdenum, and rhenium carbonyl compounds are described in this article, followed by some examples with the analogous isocyanide and cyanide ligands. The luminescence properties and potential applications of these systems are discussed. Transition metal complexes containing alkynyl ligands display a very wide structural diversity and catalytic properties, and many systems also show intriguing photoluminescence properties, especially those of rhenium(I), platinum(II), palladium(II), and the coinage metals. Studies focused on the photophysical studies and the excited‐state chemistry of selected alkynyl systems and related alkenyl, arene, and aryl complexes are outlined and discussed. Luminescent metal–carbon multiple bonded systems including the alkylidene and alkylidyne compounds have received relatively little attention, and examples have been confined to the complexes of molybdenum and tungsten. However, much effort has recently been devoted to exploring the interesting emission properties of alkylidene and alkylidyne systems with other metal centers such as rhenium, ruthenium, osmium, platinum, and coinage metals, which are outlined in this article. Some recent examples in the areas of cyclometalated complexes, especially those of rhodium(III), iridium(III), platinum(II), and gold(III) centers are highlighted in this article as many examples display impressive photophysical and photochemical behavior. Metal alkyl systems represent a special class of luminescent organometallic system due to their strong σ‐donating properties of the alkyl ligands, and the photophysical and excited‐state properties of some selected examples are described. Finally, luminescent organotransition metal compounds with application potentials in the development of new materials, photodevices, and sensory systems are summarized in various parts of this article.

Highly Efficient Phosphorescent Blue-Emitting [3+2+1] Coordinated Iridium (III) Complex for OLED Application

“…1), stabilizing the highest occupied molecular orbital (HOMO) by introducing electron-withdrawing groups on the phenyl ring, like perfluoro carbonyl (Lee et al, 2013), pentafluorophenyl (Tsuzuki et al, 2003), carborane (Furue et al, 2016), sulfonyl (Lim et al, 2017;Lin et al, 2014), dimesitylboron (Lorente et al, 2017), or formyl (Bin Mohd Yusoff et al, 2017). 2), elevating the lowest unoccupied molecular orbital (LUMO) by grafting electron-donating groups onto pyridine moieties, like methoxy group on the pyridyl ring (Yam and Lo, 2006). These two strategies positively influence the energy gap of the iridium (III) emitters, which promote the hypsochromic photoluminescence spectrum.…”