2:3 lanthanide complexes luminescent properties

Blasse G (1976) The Influence of Charge-Transfer and Rydberg States on the Luminescence Properties of Lanthanides and Actinides. 26 43-79 Blasse G (1980) The Luminescence of Closed-Shell Transition Metal-Complexes. New Developments. 42 1-41... 

Bray KL (2001) High Pressure Probes of Electronic Structure and Luminescence Properties of Transition Metal and Lanthanide Systems. 213 1 - 94 Bunz UHF (1999) Carbon-Rich Molecular Objects from Multiply Ethynylated rr-Complexes. 201 131-161... 

Until very recently, studies of the use of luminescent lanthanide complexes as biological probes concentrated on the use of terbium and europium complexes. These have emission lines in the visible region of the spectrum, and have long-lived (millisecond timescale) metal-centered emission. The first examples to be studied in detail were complexes of the Lehn cryptand (complexes (20) and (26) in Figure 7),48,50,88 whose luminescence properties have also been applied to bioassay (vide infra). In this case, the europium and terbium ions both have two water molecules... 

Anion concentrations can also be monitored through lanthanide luminescence. Once again, a wide range of pathways can be responsible for luminescence quenching. For instance, complex (60) with a pendant phenanthridinium group exhibits halide ion-dependent luminescence properties as a result of collisional quenching of the phenanthridinium-centered singlet state by halide ions.165... 

Kawa, M., and Frechet, J.M.J. (1998) Self-assembled lanthanide-cored dendrimer complexes enhancement of the luminescence properties of lanthanide ions through site-isolation and antenna effects. Chem. Mater. 10, 286-296. 

Photophysical studies have been conducted on a number of lanthanide complexes of calix[n]arenes, and a significant number of these are discussed in a recent review (79). The first europium and terbium calixarene complexes showed promising photophysical properties, with terbium luminescence lifetime of 1.5 ms and quantum yield of 0.20 in aqueous solution (80). 

The first cage lanthanide complexes studied for their photophysics were the simple 2.2.1 cryptands. The lack of a strongly absorbing chromophore, and easy approach of solvent molecules meant that their luminescence properties were disappointing in comparison to many recently studied complexes. The Lehn cryptand (L53) (Scheme 6... 

Yang, X.-P. Su, C.-Y. Kang, .-S. Feng, X.-L. Xiao, W.-L. Liu, H.-Q. Studies on lanthanide complexes of the tripodal ligand bis(2-benzimidazolylmethyl)(2-pyridyl-methyl)amine. Crystal structures and luminescence properties. J. Chem. Soc., Dalton Trans. 2000, (19), 3253-3260. 

Reeves, Z. R. Mann, K. L. V. Jeffery, J. C. McCleverty, J. A. Ward, M. D. Barigelletti, F. Armaroli, N. Lanthanide complexes of a new sterically hindered potentially hexadentate podand ligand based on a tris(pyrazolyl)borate core crystal structures, solution structures and luminescence properties. J. Chem. Soc., Dalton Trans. 1999, 349-355. 

Dossing, A. Toftlund, H. Hazell, A. Bourassa, J. Ford, P. C. Crystal structure, luminescence and other properties of some lanthanide complexes of the polypyridine ligand 6,6,-bis[bis(2-pyridylmethyl)aminomethyl]-2,2,-bipyridine. J. Chem. Soc., Dalton Trans. 1997, (3), 335-339. 

The present volume is a non-thematic issue and includes seven contributions. The first chapter byAndreja Bakac presents a detailed account of the activation of dioxygen by transition metal complexes and the important role of atom transfer and free radical chemistry in aqueous solution. The second contribution comes from Jose Olabe, an expert in the field of pentacyanoferrate complexes, in which he describes the redox reactivity of coordinated ligands in such complexes. The third chapter deals with the activation of carbon dioxide and carbonato complexes as models for carbonic anhydrase, and comes from Anadi Dash and collaborators. This is followed by a contribution from Sasha Ryabov on the transition metal chemistry of glucose oxidase, horseradish peroxidase and related enzymes. In chapter five Alexandra Masarwa and Dan Meyerstein present a detailed report on the properties of transition metal complexes containing metal-carbon bonds in aqueous solution. Ivana Ivanovic and Katarina Andjelkovic describe the importance of hepta-coordination in complexes of 3d transition metals in the subsequent contribution. The final chapter by Sally Brooker and co-workers is devoted to the application of lanthanide complexes as luminescent biolabels, an exciting new area of development. 

The heteroatoms listed in Table 10 form complexes of stoichiometry [XWi0O36]8-. The structure, based on determinations of the CeIV and UIV anions, can be regarded as the attachment of two quadridentate ligands, derived from W6Oi9 through the loss of one W06 octahedron, to the heteroatom (Figure 18). The site symmetry of the latter is approximately D4d. The XW10 anions are of only moderate stability in aqueous solution (pH5.5-8.5). Electronic, vibrational and 170 NMR spectra have been recorded. The emission spectra and luminescence properties of several of the lanthanide anions have been discussed.84... 

The formation of luminescent lanthanide complexes relies on a number of factors. The choice of coordinating ligand and the method by which the antenna chromophore is attached to it, as well as the physical properties of the antenna, are important. In order to fully coordinate a lanthanide ion, either a high-level polydentate ligand such as a cryptate 1 or a number of smaller ligands (such as 1,3-diketones, 2) working in cooperation are required. Both 1 and 2 are two of the simplest coordination complexes possible for lanthanide ions. In both cases there are no antennae present. However, the number of bound solvent molecules is decreased considerably from nine (for lanthanide ions in solution) to one to two for the cryptate and three for the 1,3-diketone complexes. 

Given their favourable luminescence properties and propensity to coordinate oxy-anions, it is perhaps surprising that complexes of lanthanide(III) ions have received comparatively little attention as anion sensors. 

Recently, many aromatic ligands derived from amines have been synthesized and the luminescence properties of their lanthanide complexes have been investigated. The ligand which is composed of an aromatic amine as a chromophore and tetra(acetic acid) as a chelation... 

Determination of lanthanide ions with a fairly low detection limit of 10-5-10-6 wt% is achieved with Ln111 /i-diketonates. Relying on this fact new, rapid, selective, and highly sensitive analytical methods essentially based on the luminescence properties of these complexes have been developed. After a preliminary work on Smm and Eum chelates (Topilova et al.,... 

Because of the higher sensitivity of Ndm ions towards deactivation through O-H oscillators, the complexes with this lanthanide have much lower quantum yields and lifetimes when compared to Ybm. The best photophysical properties are obtained with phthalexon S and since complexes with PS contain 4-5 water molecules, depending on the lanthanide ion, it is quite clear that exclusion of these water molecules from the first coordination sphere will lead to much enhanced luminescent properties. This is indeed demonstrated by bis(cyclen)-substituted PS, H736 (see fig. 36), which increases quantum yields to 0.23 and 1.45% in D2O for Ndm and Ybm, respectively (Korovin and Rusakova, 2002). 

Complexation of macrocyclic ligands to lanthanide cations has been studied extensively [207,208], One main reason for the current interest in those macro-cyclic complexes are their intrinsic paramagnetic and luminescent properties. There is also the steadily increasing number of tailor-made macrocyclic ligands [209], This section will focus on complexes which contain macrocycles as discrete counterions and in particular on the coordination chemistry of phthalocyanine (Pc) and porphyrin (Por) ligands. Schiff base ligands which display another source of amine functionalities are usually not deprotonated under the prevailing reaction conditions [210]. 

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