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The synthesis of regioisomeric asterisks (5) and (6) incorporating a benzene core with six 1‐naphthylthio or six 2‐naphthylthio arms are reported in search for new materials with optoelectronic properties. The consequences on the extension of a π system surrounding a persulfurated benzene core provide a new avenue to study the structural, photophysical, and chemical properties of such family of all‐organic phosphors. It also diverts the persulfuration mechanism after two radical cyclizations for making a [5]dithiohelicene by‐product (7) and favors dynamic sulfur component exchange reactions surrounding the core. These exchanges convert asterisks (5) and (6), non‐phosphorescent at 20 °C to the highly phosphorescent (4) (ϕ ∼100 %, solid state at 20 °C). For asterisks (5) and (6), the absence of the typical phosphorescence of the per(phenylthio)benzene core in the solid state at 20 °C and the presence of a weak naphthalene‐based phosphorescence at 77 K is attributed to an energy transfer from the triplet state of the persulfurated benzene core to the outer naphthalene moieties, resulting in an antenna system. [ABSTRACT FROM AUTHOR]

We have designed a new multichromophoric system based on a tetra(phenylthio)pyrene core appended with four terpyridine units. The system behaves as a molecular antenna that collects light with the peripheral units and funnels the energy to the very highly luminescent core. The addition of metals ions to the investigated system can not only switch the direction of the intramolecular energy transfer, but also control the formation of three-dimensional nanoscopic objects in a dual function. [ABSTRACT FROM AUTHOR]

The development of multicomponent (supramolecular) systems that can perform predetermined functions under external control -- i.e., molecular devices -- is a challenging task in chemistry and a fascinating objective in the frame of a bottom-up approach to nanostructures. In this context light signals can be conveniently used both for supplying energy to the system and for probing its states and transformations. The aim of this tutorial review is to recall a few basic aspects of light-induced processes that can be used to "write" and "read" onto molecular and supramolecular systems. These principles are illustrated through some examples of artificial molecular devices and machines taken from our work, which provide a flavour of current research. They are molecular and supramolecular systems that operate and/or perform valuable functions by exploiting photoinduced energy- or electron-transfer processes, photoisomerization reactions, or photoinduced proton transfer. The choice of these examples was based on both their intrinsic importance for the referred topic and their educational value. In the last section of the review potential applications, limitations and future directions of the research in the field of artificial molecular devices and machines are also discussed. [ABSTRACT FROM AUTHOR]

We have designed two novel dendrimers with cyclam cores with appended poly(amido amine) (PAMAM) dendrons, decorated at the periphery with four and eight dansyl chromophores, respectively. The photophysical properties of the dendrimers and their Nd3+ complexes have been investigated. The energy-transfer efficiency to the lanthanide ions from these dendrimers has been studied as a function of the generation. It has been observed that an increase in the dendrimer generation as well as the number of amide units enhances the energy transfer to the lanthanide ion. [ABSTRACT FROM AUTHOR]

We have investigated the formation of host–guest complexes between dendrimers of the poly(propylene amine) family functionalized with dansyl units at the periphery (hosts) with dye molecules (guests). Each dendrimer nD, where the generation number n goes from 1 to 5, comprises 2n+1 (i.e. 64 for 5D) dansyl functions in the periphery and 2n+1−2 (i.e. 62 for 5D) tertiary amine units in the interior. The most thoroughly investigated systems were those with eosin as a guest. The results obtained show that: (i) the nD dendrimers dissolved in dichloromethane solution extract eosin from aqueous solutions; (ii) the maximum number of eosin molecules hosted in the dendrimers increases with increasing dendrimer generation, up to a maximum of 12 for the 5D dendrimer; (iii) the fluorescence of the peripheral dansyl units of the dendrimers is completely quenched via energy transfer by the hosted eosin molecules; (iv) the fluorescence of the hosted eosin molecules is partially quenched; (v) the eosin molecules can occupy two different sites (or two families of substantially different sites) in the interior of the dendritic structure; (vi) excitation of eosin hosted in the dendrimers causes sensitization of the dioxygen emission via eosin triplet excited state. The behavior of fluorescein and rose bengal is qualitatively similar to that of eosin, whereas naphthofluorescein is not extracted. The maximum number of dye molecules extracted by the 4D dendrimer is 25 for rose bengal and ca. 1 for fluorescein, showing that the formation of host–guest species is related to the electronic properties rather than to the size of the dye molecules. [Copyright &y& Elsevier]

Two Ru2+complexes containing terpyridine ligands appended with terthiophene units connected by a methyleneoxy or an alkynyl bridge show very different luminescent behaviours: the former is non-luminescent at 298 K owing to a photoinduced energy transfer process to the terthiophene moiety, while the latter exhibits an extraordinary long excited state lifetime because of an energy reservoir effect. [ABSTRACT FROM AUTHOR]

Zn(ii) complexation drives the formation of a light-harvesting antenna constituted by two multicomponent luminescent ligands: a cyclam-cored dendrimer decorated at the periphery with 16 naphthyl units and an anthracene-based molecular clip. [ABSTRACT FROM AUTHOR]

Multichromophoric systems capable of operating as light ‐ harvesting antennae have recently been attracting increasing attention. In their Full Paper on page 10661 ff., M. Gingras, G. Bergamini et al. describe the synthesis, characterization, and metal ‐ ion coordination of a multichromophoric tetra(terpyridine) ligand that can be used to make new supramolecular systems with tailor ‐ made photophysical properties and aggregation states. [ABSTRACT FROM AUTHOR]

The Young Chemists Special Issue has been put together to celebrate the past winners of the European Young Chemist Award (EYCA), presented at the first four EuCheMS Congresses, and to highlight the great diversity of research currently being conducted by young chemists from all over the world. Nine manuscripts that highlight this diversity have been selected to feature in the cover picture. In the top row from left to right: T. Noël et al. (p. 10562 ff.), A. Mateo ‐ Alonso et al. (p. 10626 ff.), and M. Gingras, G. Bergamini et al. (p. 10661 ff.). In the middle row from left to right: D. Vione et al. (p. 10590 ff.), S. Carenco (p. 10616 ff.), and N. Cramer et al. (p. 10654 ff.). In the bottom row from left to right: H. N. Miras (p. 10554 ff.), A. Tavassoli et al. (p. 10608 ff.), and E. Coronado, G. Mínguez Espallargas et al. (p. 10695 ff.). [ABSTRACT FROM AUTHOR]

Abstract: Because of its ability to form stable complexes with a wide variety of metal ions, cyclam (1,4,8,11-tetraazacyclotetradecane) is one of the most studied ligands in coordination chemistry. Functionalizing the cyclam unit with photoactive dendrons open a door to construct giant homo- and heteroleptic metal complexes that display interesting spectroscopic properties, particularly as far as luminescence is concerned. Light is a tool both to study metal coordination processes, and to act as input or output in order to achieve the desired function. This paper reviews some results obtained with metal complexes of cyclam-based dendrimers capable of acting as: (i) sensor, (ii) logic gates, and (iii) molecular antennae. [Copyright &y& Elsevier]

Abstract: The photosensitivity of metal complexes has been known for a long time. Early studies on ligand photosubstitution and photoredox decomposition reactions of metal complexes of simple inorganic ligands (e.g. NH3, CN−) have been followed by accurate investigations on the photophysical behavior (luminescence quantum yields and lifetimes) and on the use of metal complexes in bimolecular processes (energy and electron transfer). A large number of complexes, stable towards photodecomposition, but capable of undergoing excited state redox processes, have been used for interconverting light and chemical energy. More recently, combination of supramolecular chemistry and photochemistry has led to the design and construction of multicomponent systems capable of performing light induced functions. In this field, luminescent and/or photoredox reactive metal complexes are presently used as essential components for a bottom-up approach to the construction of molecular devices and machines. Examples of molecular devices for processing light signals and of molecular machines powered by light energy, based on coordination compounds, are illustrated. [Copyright &y& Elsevier]