Luminescent supramolecular complexes

The first descriptions of heteronuclear luminescent supramolecular complexes were given by Fackler et al. in 1988 and 1989. In these studies, one gold-thallium and one gold-lead complex were reported. As in the case of the gold-silver dinuclear systems, the extended systems appeared as a result of the unidirectional polymerization of dinuclear or trinuclear units through metal-metal interactions. These were prepared by reaction of the gold precursor [PPN][Au(MTP)2] (PPN = N(PPh3)2 ... 

Sabbatini, N. Guardigli, M. Lehn, J.-M. Luminescent lanthanide complexes as photochemical supramolecular devices. Coord. Chem. Rev. 1993,123, 201-228. Sabbatini, N. Guardigli, M. Manet, I. Lanthanide complexes of encapsulating ligands as luminescent devices. Adv. Photochem. 1997, 23, 213—278. 

Of the metals that form luminescent supramolecular entities with gold, that for which most complexes are known is thallium in its +1 oxidation state. As described below, in recent years the contributions of several laboratories have been reported. Nevertheless, in some cases, the papers also report similar reactions with other metals, leading to similar structures. In order to maintain a congruent synthetic description, those examples will be discussed together as they appear in the original work. 

As described above, among the several closed-shell metal ions that form luminescent supramolecular entities with gold, thallium(I) forms the most numerous examples. While aurophilic attractions can be considered the upper extreme of the metallophilic interactions (with values up to 46 kJ mol-1), intermetallic contacts involving T1(I) centers appear as the weakest ones (even <20 kJ mol-1),46 which is explained by the enhancement of the Au---Au interactions and the weakening of the Van der Waals attractions between the s2 metal atoms produced by the relativistic effects.47 Nevertheless, the complexes in which this interaction appears are surprisingly stable, with additional electrostatic, packing forces, or the ligand architecture, responsible for this fact. 

Lees AJ (2001) Luminescent metal complexes as spectroscopic probes of monomer/polymer environments. In Ramamurthy V, Schanze KS (Eds) Optical Sensors and Switches. Molecular and Supramolecular Photochemistry Series, Vol 7, Chap 5. Marcel Dekker, New York, p 209... 

Gunnlaugsson, T. and Leonard, J.R (2005) Responsive lanthanide luminescent cyclen complexes from switching/sensing to supramolecular architectures. Chemical Communications, 3114-3131. 

Lees, A. J. Luminescent Metal Complexes as Spectroscopic Probes of Monomer/Polymer Environments. In Optical Sensors and Switches Ramamurthy, V., Schanze, K. S., Eds. Molecular and Supramolecular Photochemistry ries, Vol. 7 Marcel Dekker New York, 2001 Chap. 5, pp 209-255. 

The approaches to heterometaUic systems outlined above all rely upon coordination chemistry, whether to a metal ion or a nanoparticle surface. Supramolecular interactions can also play a role in assembling heterometaUic systems. For instance, Sambrook et al. prepared a pseudo-rotaxane (18) templated around a chloride ion (Fig. 9) in which lanthanide ions are bound to the thread while a luminescent rhenium complex is bound to the macrocycle component [49]. Thus there is no direct link between the donor chromophore and the lanthanide ion, and Dexter exchange is not viable in the absence of bonds enforcing Forster energy transfer. This extreme of behaviour helps to rationalize the behaviour of more conventionaUy... 

Sabbatini N, Guardigli M, Lehn J-M (1993) Luminescent lanthanide complexes as photochemical supramolecular devices. Coord Chem Rev 123 201-228... 

Gunnlaugsson T, Leonard JP. Responsive Lanthanide Luminescent Cyclen Complexes from Switching/Sensing to Supramolecular Architectures. Chem Commun 2005 2005 3114-3131. 

Extended linear chain inorganic compounds have special chemical and physical properties [60,61], This has led to new developments in fields such as supramolecular chemistry, acid-base chemistry, luminescent materials, and various optoelectronic applications. Among recent examples are the developments of a vapochromic light emitting diode from linear chain Pt(II)/Pd(II) complexes [62], a luminescent switch consisting of an Au(I) dithiocarbamate complex that possesses a luminescent linear... 

Vickery, J.C., Olmstead, M.M., Fung, E.Y. and Balch, A.L. (1997) Solvent-stimulated luminescence from the supramolecular aggregation of a trinuclear gold(I) complex that displays extensive intermolecular Au Au interactions. Angewandte Chemie, 109, 1227-1229 (1997) Angewandte Chemie (International Edition in English), 36, 1179-1181. 

When interaction between the metal-based components is weak, polynuclear transition metal complexes belong to the field of supramolecular chemistry. At the roots of supramolecular chemistry is the concept that supramolecular species have the potential to achieve much more elaborated tasks than simple molecular components while a molecular component can be involved in simple acts, supramolecular species can performIn other words, supramolecular species have the potentiality to behave as molecular devices. Particularly interesting molecular devices are those which use light to achieve their functions. Molecular devices which perform light-induced functions are called photochemical molecular devices (PMD). Luminescent and redox-active polynuclear complexes as those described in this chapter can play a role as PMDs operating by photoinduced energy and electron transfer processes. ... 

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