Perylene ligands

Another Pd-Pd-Pd-Pd bent chain is found in the tetrapalladium sandwich complex with the polycyclic aromatic hydrocarbon perylene shown in Equation (17). The perylene ligand is bonded to the tetrapalladium chain in a fi4-rf fashion. The acetonitrile ligands can be easily replaced by pyridine ligands, and the perylene ligands... 

Four consecutive C = C units embedded in polycyclic aromatic ligand (PAL) is demonstrated to stabilize a Pd4 chain. The Pd-Pd-Pd-Pd chain is sandwiched by two perylene ligands (Scheme 47) in coordination... 

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. 

A perylene derivative called PIPER was the first example of a small ligand behaving as a driver in the assembly of quadruplex structures.Gel-shift experiments demonstrate that PIPER can dramatically accelerate the association of a DNA oligomer containing two tandem repeats of the human telomeric sequence (TTAG3) into di- and tetrameric G-quadruplexes. In... 

Several classes of ligands have been described such as porphyrins, perylenes, amidoanthracene-9,10-diones, 2,7-disubstituted amidofluoren-ones, acridines, ethidium derivatives,disubstituted triazines, fluoroquinoanthroxazines, indoloquinolines, dibenzophenanthrolines, ... 

Two of the classical bis-nitrogen ligands to assemble porphyrins (predominantly zinc metallated) are the bidentate l,4-diazabicyclo[2.2.2]octane (DABCO) and 4,4 -bipyridine (bipy). Other di-topic nitrogen-ligands studied include hydrazine, 4,4 -bipyrimidine, diaza-pyrene, 5,5 -dicyano-2,2 -bipyri-dine, perylene-bisimide, extended bipyridine units and non-covalently linked di-pyridyl ligands via bipy-metal interactions. The formation of various bis-porphyrin and multiporphyrin assemblies using these versatile ligands were studied in detail by Sanders, Anderson, Hunter, Branda and many others. The structures of the supramolecular multi-porphyrin architectures are schematically represented in Fig. 9. 

EPR spectroscopy has been used very extensively in investigations of hemoproteins and heme model systems. In all studies on high- and low-spin hemoproteins, no hf interaction with N, or (enriched) Fe was resolved in frozen solutions or in single crystals. The first EPR observation of ligand hf structure from heme pyrrole nitrogens in the model system ferriprotoporphyrin(IX) ester doped into perylene single crystals was reported by Scholes The hfe tensors were found to be essentially isotropic wi a, ol = 8.68 MHz, which corresponds to a spin density fj = 2.7% in the nitrogen 2s-orbital. 

Wurthner, F. Sautter, A. Highly fluorescent and electroactive molecular squares containing perylene bisimide ligands. Chem. Commun. 2000, (6). 445-446. 

First dendritic energy transfer system was published by Balzani et al. in 1992, which was composed of complexes of ruthenium and osmium. Following this, first unidirectional energy transfer from the phenyl acetylene superficial units to the perylene core was reported by Xu and Moore Dendritic benzyl ether ligands coordinated to the... 

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