Perylene complexes

Related to our work on the bipyridyl acetylides, we have also demonstrated that proper selection of the acetylide ligand makes possible the design of Ptn terpyridyl complexes that exhibit acetylide 3IL excited states [20]. The perylene complexes 3.7 and 3.8 do not display photoluminescence, however, indirect evidence that the triplet excited state is indeed populated was indicated through the sensitization of singlet oxygen. Transient absorption measurements (Fig. 7) confirmed that regardless of the polyimine ligand used, the lowest excited state in these molecules is 3IL localized in the perylenylacetylide moiety. It is clear in Fig. 7a and b that the identical features are observed in the absorption difference spectra of 3.7 and 3.8, whereas the difference spectrum of the phenylacetylide complex is clearly distinct, illustrative of the marked differences between 3IL and 3CT excited absorptions. 

L. Alcacer and A. H. Maki, Electrically conducting metal dithiolate-perylene complexes, J. Phvs. Chem. 78 215 (1974). 

All other perylene complexes with organic counterparts present the 1 1 stoichiometry and alternate stacking, being consequently poor conductors. Structural data are... 

Figure 2.6. Overlap of donor and acceptor molecules for several perylene complexes with organic molecules, (a) TCNQ (tetracyanoquinodimethane) in Per3(TCNQ). (Reproduced by permission of International Union of Crystallography, from ref. 19) in the 1 1 complex the overlap is slightly twisted relative to this one. (b) Fluoranil. (Reproduced by permission of International Union of Crystallography, from ref. 23). (c) PMDA (pyxomellitic dianhydride). (Reproduced by permission of The American Chemical Society, from ref 24) (d) HCBD (hexacyanobutadiene). (Reproduced by permission of Elsevier Science, from ref 26). (e) TCNE (tetracyanoethylene). (Reproduced by permission of International Union of Crystallography, from ref 25.)...

PERYLENE COMPLEXES WITH SIMPLE INORGANIC ANIONS... 

Perylene complexes with other types M-dithio or M-diseleno complexes as anions, such as Au(i-mnt)2 [106,107], Au(i-mns)2 [108], Au(cdc)2 [109], Ni-thiete [110] and Ni(tcdt)2 [111], have also been reported (see Tables 2.8 and 2.9). Many of these anions can be taken as ligand variants of the corresponding M(mnt)2 complexes. However these compounds have been obtained only with one type of metal M, lacking the extensive and systematic exploration of the metal effect previously described for the Per2M(mnt)2 family. 

In the perylene complex with the gold-bisdicyano-dithiocarbimate anion, Per2Au(cdc)2, differences from the previously mentioned Au complexes, due to the... 

Two typical dye molecules. The europium complex (a) transfers absorbed light to excited-state levels of the complexed Eu , from which lasing occurs. The perylene molecule (b) converts incident radiation into a triplet state, which decays slowly and so allows lasing to occur. 

Benzo[ghi]perylene (1,12-benzoperylene) [191-24-2] M 276,3, m 273°, 277-278.5°, 278-280°, Purified as light green crystals by recrystn from CfiH6 or xylene and sublimes at 320-340° and 0.05mm [UV Helv Chim Acta 42 2315 7959 Chem Ber 65 846 1932 Fluoresc. Spectrum J Chem Soc 3875 7954]. 1,3,5-Trinitrobenzene complex m 310-313° (deep red crystals from C6Hg) picrate m 267-270° (dark red crystals from CgH6) styphnate (2,4,6-trinitroresorcinol complex) m 234° (wine red crystals from CgH6). It recrystallises from propan-l-ol [J Chem Soc 466 7959]. 

The theory and development of a solvent-extraction scheme for polynuclear aromatic hydrocarbons (PAHs) is described. The use of y-cyclodextrin (CDx) as an aqueous phase modifier makes this scheme unique since it allows for the extraction of PAHs from ether to the aqueous phase. Generally, the extraction of PAHS into water is not feasible due to the low solubility of these compounds in aqueous media. Water-soluble cyclodextrins, which act as hosts in the formation of inclusion complexes, promote this type of extraction by partitioning PAHs into the aqueous phase through the formation of complexes. The stereoselective nature of CDx inclusion-complex formation enhances the separation of different sized PAH molecules present in a mixture. For example, perylene is extracted into the aqueous phase from an organic phase anthracene-perylene mixture in the presence of CDx modifier. Extraction results for a variety of PAHs are presented, and the potential of this method for separation of more complex mixtures is discussed. 

Since the discovery of the first organic semiconductor perylene-bromine complex in 1954 [1], a large number of molecular conductors, including more than 100 molecular superconductors, have been prepared. Conducting molecular materials are characterized by the following features ... 

It has been reported that the electrical properties of single molecules incorporating redox groups (e.g. viologens [114, 119, 120, 123, 124], oligophenylene ethynylenes [122, 123], porphyrins [111, 126], oligo-anilines and thiophenes [116, 127], metal transition complexes [118,128-132], carotenes [133], ferrocenes [134,135],perylene tetracarboxylic bisimide [93, 136, 137] and redox-active proteins [138-143]), can be switched electrochemically. Such experiments, typically performed by STM on redox-active molecules tethered via Au-S bonds between a gold substrate and a tip under potential control, allow the possibility to examine directly the correlation between redox state and the conductance of individual molecules. 

Redox molecules are particularly interesting for an electrochemical approach, because they offer addressable (functional) energy states in an electrochemically accessible potential window, which can be tuned upon polarization between oxidized and reduced states. The difference in the junction conductance of the oxidized and the reduced forms of redox molecules may span several orders of magnitude. Examples of functional molecules used in these studies include porphyrins [31,153], viologens [33, 34,110,114,154,155], aniline and thiophene oligomers [113, 146, 156, 157], metal-organic terpyridine complexes [46, 158-163], carotenes [164], nitro derivatives of OPE (OPV) [165, 166], ferrocene [150, 167, 168], perylene tetracarboxylic bisimide [141, 169, 170], tetrathia-fulvalenes [155], fullerene derivatives [171], redox-active proteins [109, 172-174], and hydroxyquinones [175]. 

Many large band-gap organic materials have been explored for blue emission. To summarize, they are the distyrylarylene series, anthracenes, perylenes, fluorenes, heterocyclic compounds, and metal complexes. 

Since the same dye molecules can serve as both donors and acceptors and the transfer efficiency depends on the spectral overlap between the emission spectrum of the donor and the absorption spectrum of the acceptor, this efficiency also depends on the Stokes shift [53]. Involvement of these effects depends strongly on the properties of the dye. Fluoresceins and rhodamines exhibit high homo-FRET efficiency and self-quenching pyrene and perylene derivatives, high homo-FRET but little self-quenching and luminescent metal complexes may not exhibit homo-FRET at all because of their very strong Stokes shifts. 

Nentral perylene reacts with N02, giving the cation-radical. Flowever, its formation is, in principle, a result of a-complex splitting. Another possible route of a-complex splitting consists of proton elimination and nitro perylene formation. As experiments show, the nitration of perylene is accompanied with collateral reactions of PerH, such as recombination and interaction with solvent molecules (Eberson and Radner 1985). This testifies to the release of cation-radical. 

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