Luminescence helicate structures

In addition to electrical properties, the optical properties see Luminescence Behavior Photochemistry of Organ-otransition Metal Compounds) of the metal metal bonded unit have also received increased attention. Luminescence tribochromism hght emission that occurs with mechanical grinding - has been displayed by a An An dimeric complex where the monomeric unit with a An An separation of 2.8797 A arranges in a helical structure with alternating longer Au Au distances as shown in Figure 3. ... 

Figure 4.21 The structure of [Lu(19)2](CH30H)(H20)] + [37]. (Reproduced with permission from C. Piguet, A.R Williams, C. Bemardine and J.C.G. Btinzli, Structural and photophysical properties of lanthanide complexes with planar aromatic tridentate nitrogen ligands as luminescent building blocks for triple-helical structures, Inorganic Chemistry, 32, 4139, 1993. 1993 American Chemical Society.)...

Figure 11.7 depicts typical absorption and luminescence spectra for polysilanes. Absorption peak energies are within the range 3 to 4 eV and are determined mainly by backbone conformation. Photoluminescent efficiencies are high (10% to 50%) and the apparent Stokes shift increases with the breadth of the absorption spectrum. Whenever a single screw-sense helical structure pertains, the absorption and emission bands are narrow and the Stokes shift is small. Such a polymer is poly[decyl-(5)-2-methylbutylsilane], the chiral center within the (S)-2-methylbutyl substituent determining the screw sense. Such... 

Kguet C., A. F. Williams, G. Bemardinelli, J.-C. G. Biinzli. Structural and Photophysical Properties of Lanthanide Complexes with Planar Aromatic Tridentate Nitrogen Ligands as Luminescent Building Blocks for Triple-Helical Structures, Inorg. Chem., 32,4139-4149 (1993). 

Conti et al. (1996) solved the crystal structure of the P. pyralis luciferase at 2.0 A resolution. The protein is folded into two compact domains, a large N-terminal portion and a small C-terminal portion. The former portion consists of a /1-barrel and two /1-sheets. The sheets are flanked by a-helices to form an aflafia five-layered structure. The C-terminal portion of the molecule forms a distinct domain, which is separated from the N-terminal domain by a wide cleft. It is suggested that the two domains will close up in the course of the luminescence reaction. 

Shiga, T., Ohba, M., and Okawa, H. (2004) A series of trinuclear Cu Ln Cu complexes derived from 2,6-di(acetoacetyl)pyridine synthesis, structure, and magnetism. Inorganic Chemistry, 43, 4435 446. Albrecht, M., Schmid, S., Dehn, S., et al. (2007) Diastereoselective formation of luminescent dinuclear lan-thanide(III) helicates with enantiomerically pure tartaric acid derived bis(P-diketonate) ligands. New Journal of Chemistry, 31, 1755-1762. 

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