Emittance analogue

Goelenterate. Coelenterates Penilla reformis (sea pansy) -cradViequoreaforskalea (jelly fish) produce bioluminescence by similar processes (223). The basic luciferin stmcture is (49) (224) and excited amide (50) is the emitter. The stmctural relationship to Varela is evident. A stmctural analogue where R = CH is active ia bioluminescence. The quantum yield is about 4% (223), with at 509 nm (56). This reaction iavolves a charge transfer between green fluorescent proteia and the excited-state coelenterate oxylucifetin. 

Formation of the excited amide anion of coelenteramide as the light emitter in the luminescence reaction of coelenterazine was experimentally supported by the experiment of Hori et al. (1973a), in which 2-methyl analogue of coelenterazine was used as the model compound. The summary of their work is as follows In the presence of oxygen, la and lb in DMF emitted bright blue luminescence (Amax 480 and 470 nm, respectively), and produced the reaction products Ha and lib, respectively. The fluorescence emission of lib (Amax 470 nm) and that of the spent chemiluminescence reaction of lb, both in DMF plus a base (potassium r-butoxide), were identical to the chemiluminescence emission of lb in DMF. The fluorescence emission of Ha... 

Imai, Y., et al. (2001). Fluorescence properties of phenolate anions of coe-lenteramide analogues the light-emitter structure in aequorin bioluminescence. J. Photocbem. Photobiol., A Chemistry 146 95-107. 

Knoevenagel condensation of 1 2.1 stoichiometric ratio of the pyran and aldehyde generates a pure bis-condensation product. Due to the extended ir-conjugated system, these bis-condensed red emitters are about 40-50 nm red-shifted compared with their respective mono-substituted DCM analogues. 

Complexes containing the 3,5-dinitrosalicylate ion, e.g. [Ln2(C2H202N2)3],- H20 (u = 7 -> 15), and methylsalicylate (MesaP ), e.g. [Ln(Mesal)2(OH)-(H2O)] (Ln = La, Pr, Nd, Sm, Gd, Dy, Er, Yb and have been reported. Tris-salicylaldehydato (said ) complexes, Ln(sald)3 (La, Pr, Nd, Sm, Eu, or Tb) form 1 1 adducts with o-phenanthroline (o-phen), aa -bipyridyl, quinoline, and pyridine. The luminescence spectrum of the Eu " complexes showed that, in the solid state, the symmetrically forbidden electric dipole transition intensity was much enhanced for the o-phen adduct when compared to its salicylate analogue. The simple said" complexes were very poor emitters. 

Besides these impressive results, excellent examples of highly stable blue emitter materials have been reported by Mullen et al. [55-59] and Scherf et al. [43,60]. These authors concentrated on bridged polyparaphenylenes, polyindenofluorenes, polyphenanthrylenes, and other ladder-type analogues... 

Since the response characteristics of these optical components are not linear, nor flat, we need an analogue system in order to be able to measure color. The analogue system simply corrects for the non-linearity of the source and detector, as shown in the following for emittance. This is shown in 6.7.28., on the next page. 

The C5 position of dU has been used to attach a variety of labels or reporter groups, in particular fluorophores ° (see section 3.5). The pyrene-modified analogue (39) has been used to detect RNA bulge conformations in the HIV-TAR RNA sequence where the fluorescence is greatly enhanced,and as a donor for the red emitter nile red (40) when the two dyes are adjacent in duplex DNA the result is white light that is emitted upon excitation of (39). A zinc-porphyrin complex has been added to C5 of dU for use in electron transfer. Norbornene has been attached via an alkyne linker for post-synthetic modification with nitrile oxides in a copper-free Click reaction, " and various dienes have been attached for Diels-Alder tagging of DNA. The photoaffinity tag (41) has been incorporated into DNA adjacent to a damaged DNA base (8-oxo-dG or thymine dimer) such that when exposed to repair systems, the repair enzyme is trapped by the diazirine for mass spectroscopic characterisation. ... 

Red triplet emitter with high quantum yield for OLEDs which has shown exceptionally high efficiency ( 7 %) at low injection current [131]. Used as a dopant in host materials like 4,4 -bis(N-carbazolyl)-l,l -biphenyl (CBP) and Alqs (6.1). Has also been used as a phosphorescent dye in LEDs [132]. Widely studied as a dic [diocescent oxygen sensor. The Pd analogue is also used in oxygen sensors studies it has weaker emission, but a much longer triplet lifetiine. 

The microwave analogue of this optical experiment is quite simple to demonstrate, with the help of a 3-cm emitter and receiver and two prismatic blocks of paraffin wax. 

Figure 7.4 shows the structures of typical electron transport organic semiconductors. Alq3, which can act both as an electron conductor and green emitter, was used by Tang in his first OLEDs and is still in use today. Besides metal complexes electron deficient heterocycles are frequently used as electron transport materials. The triazine derivative TPT [14, 15], the oxadiazole PBD and its spiro analogue spiro-PBD [16, 17] and the benzimidazole TPBI serve as typical examples. 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) has a very low HOMO level and is often used as a hole blocking layer. 

---