Complexed Nitrogen Heterosuperbenzene: The Coordinating Properties of a Remarkable Ligand
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- 作者：Sylvia M. Draper ; Daniel J. Gregg ; Emma R. Schofield ; Wesley R. Browne ; Marco Duati ; Johannes G. Vos ; and Paolo Passaniti
- 刊名：Journal of the American Chemical Society
- 出版年：2004
- 出版时间：July 21, 2004
- 年：2004
- 卷：126
- 期：28
- 页码：8694 - 8701
- 全文大小：207K
- 年卷期：v.126,no.28(July 21, 2004)
- ISSN：1520-5126
文摘
Tetra-peri-(tert-butyl-benzo)-di-peri-(pyrimidino)-coronene 1, the parent compound of the nitrogenheterosuperbenzene family N-HSB, is employed as a novel monotopic ligand in the formation of [Pd(
3-C3H5)(1)]PF6 2 and [Ru(bpy)2(1)](PF6)2 (where bpy = 2,2'-bipyridine 3a and d8-2,2'-bipyridine 3b). TheseN-coordinated complexes are fully characterized by 1H NMR and IR spectroscopy and ESI-MS. Metalcoordination has a profound effect on both the absorption and the emission properties of 1. Pd(II) coordinationcauses a red-shift in the low-energy absorptions, a decrease in the intensity of the n-
* absorptions, anda quenching of the emission. Ru(II) coordination causes absorption throughout the visible region and createstwo new complexes that join an elite group of compounds known as "black" absorbers. 3a and 3b possesstwo discernible 1MLCT bands. The one of exceptionally low energy (
max = 615 nm) has an associated3MLCT emission (max = 880 nm) due to the unprecedented electron delocalization and acceptor propertiesof the rigid aromatic N-HSB 1. Both Ru(II) complexes are near-IR emitters with unusually protractedemission lifetimes of 320 ns at 77 K. They are photochemically inert, and their electrochemical propertiesare consistent with the presence of a low-lying * orbital on 1. The first two reversible reductions (E1/2(CH3CN), -0.54 V, -1.01 V vs SCE) are due to the stepwise reduction of 1 and are anodically shifted ascompared to [Ru(bpy)3]2+. Temperature- and concentration-dependent NMR studies on 2 and 3a suggestextensive aggregation is occurring in solution.
3-C3H5)(1)]PF6 2 and [Ru(bpy)2(1)](PF6)2 (where bpy = 2,2'-bipyridine 3a and d8-2,2'-bipyridine 3b). TheseN-coordinated complexes are fully characterized by 1H NMR and IR spectroscopy and ESI-MS. Metalcoordination has a profound effect on both the absorption and the emission properties of 1. Pd(II) coordinationcauses a red-shift in the low-energy absorptions, a decrease in the intensity of the n-* absorptions, anda quenching of the emission. Ru(II) coordination causes absorption throughout the visible region and createstwo new complexes that join an elite group of compounds known as "black" absorbers. 3a and 3b possesstwo discernible 1MLCT bands. The one of exceptionally low energy (max = 615 nm) has an associated3MLCT emission (max = 880 nm) due to the unprecedented electron delocalization and acceptor propertiesof the rigid aromatic N-HSB 1. Both Ru(II) complexes are near-IR emitters with unusually protractedemission lifetimes of 320 ns at 77 K. They are photochemically inert, and their electrochemical propertiesare consistent with the presence of a low-lying * orbital on 1. The first two reversible reductions (E1/2(CH3CN), -0.54 V, -1.01 V vs SCE) are due to the stepwise reduction of 1 and are anodically shifted ascompared to [Ru(bpy)3]2+. Temperature- and concentration-dependent NMR studies on 2 and 3a suggestextensive aggregation is occurring in solution.