Current Inorganic Chemistry (v.1, #1)

Preface by Yann GARCIA (i-i).
Nowadays, with the rapid development of information communication, it has become extremely important to be aware and upto-date of the latest advances and current trends in our own field. Keeping the same in consideration, a reliable and high impactfactor journal covering latest developments and hot topics in inorganic chemistry was aimed at. Strengthened by the earlysuccess of Curr. Org. Chem. (2009 ISI 5 year IF: 3.809) Bentham Science publishers are proud to announce the release ofCurrent Inorganic Chemistry, a new peer-reviewed journal that will be best suited for reviews and topical issues on majoradvances in all areas of Inorganic Chemistry. No publication fee is requested but an open access plus option will be offered.There is no doubt that the release of a new journal, which is both a challenging and exciting event for the Inorganic Chemistrycommunity, will be warmly welcomed as attested by the five forthcoming special issues that are already planned this year. Tostart with, we are delighted to welcome this month, Dr Loic J. Charbonniere as a guest editor of the first hot topic issue thatcovers recent developments in coordination chemistry of lanthanide cations. I would like to take this opportunity to thank Bentham Science for appointing me as the Editor of the journal, and toacknowledge Ms. Anila Mufti and Ms. Humaira Bilal for their enthusiasm, dedication and continual support.

Even though the history of lanthanide chemistry dates back to the end of the eighteens century, this field of coordinationchemistry has continuously strived new researches and developments associated to the exceptional spectroscopic and magneticproperties of this particular series of the periodic table. Phosphors for lighting or display devices or contrast agents used innuclear magnetic resonance imaging are daily life applications originating from this long chemical saga in which all the stepsgoing from the discovery of these elements to their use in practical devices have been climbed by the passionate works ofresearchers, engineers and highlighted spirits. This issue of Current Inorganic Chemistry is devoted to some of the most recent developments in the coordinationchemistry of lanthanide cations. It aims both at reviewing the latest achievements in some established fields and also atdirecting the interested readers to rather new domains and perspectives that have emerged in the recent years. The firstcontribution is dedicated to some basic photophysical properties of luminescent lanthanide complexes with a survey onlanthanide based markers for luminescence biolabelling and their associated chemistry, and it is followed by a second articlewhich covers the use of luminescent lanthanide complexes for applications in energy transfer experiments and influoroimmunoassays. Progresses in anion sensing will be given in a third chapter, with a special emphasis on complexes withcyclen based structures and the following article will be devoted to the luminescence properties of heteropolynuclear structures.The fifth contribution of this topical issue will be focused on the latest advance of NMR contrast agents and more specificallyon smart agents for sensing endogeneous cations. Finally, the two last chapters aim at highlighting some emerging and flourishing fields of lanthanide containing compounds.They cover the aspects of in silico modelisation of the coordination chemistry of 4f elements for investigation of theirspectroscopic and magnetic behaviour, and the developments and properties of lanthanide based nanoparticles with specialattention to their biomedical applications. Finally, I would like to acknowledge warmly the contributors of this special inaugural issue, who all agreed enthusiasticallyto take part in this adventure that is the launching of a new journal, and the reviewers who took of their precious time tocontribute to ensure a high scientific quality in the contents of the articles. Many thanks to all of you.

Luminescent Lanthanide Labels by Loic J. Charbonniere (2-16).
This chapter describes the properties of luminescent lanthanide complexes that can be used in biological solutionsfor luminescence based labelling applications. The particular photo-physical specifications of this family of luminescentlabels will be described, followed by the chemical and physico-chemical requirements necessary to reach high luminescenceand good labelling activity. Following these criteria, examples of the literature will be detailed, following a classificationbased on the chemically activated function used in the labelling process.

Lanthanide Complexes in FRET Applications by Daniel Geißler, Niko Hildebrandt (17-35).
In this article, the main principles of Forster resonance energy transfer (FRET) are described with special emphasison luminescent lanthanide complexes (LLCs) in modern fluorescence spectroscopy and microscopy and their use inbiomolecular analysis. The theoretical fundamentals of FRET are explained and the unique photophysical properties ofLLCs are presented. Their narrow emission bands, long excited-state lifetimes and large -Stokes shifts- make LLCs verypromising energy donors for various FRET systems. Numerous recent literature examples as well as commercial applications,demonstrating the particular advantages of LLCs in FRET spectroscopy and microscopy, are reported. Afterwards,the benefits of multi-parametric FRET measurements using LLC donors are emphasized. The multiplexed approach allowsthe simultaneous detection of several analytes or binding events, which makes it especially important for modernhigh-throughput-screening as well as low-cost lab-on-a-chip devices. Finally, semiconductor quantum dots (QDs) and theadvantages of their use as novel FRET acceptors are presented. A combination of LLCs and QDs in FRET provides extraordinarydonor-acceptor pairs with outstanding properties, and long biomolecular distances of up to 20 nm become accessible.Extremely high sensitivity combined with multiplexed detection make the LLC-QD FRET pairs substantial forapplication in modern time-resolved fluoroimmunoassays (TR-FIA). Luminescent lanthanide complexes have been veryefficient tools in various FRET applications and regarding the ever increasing amount of newly arising biomolecular questionsand the development of novel fluorescent materials the future of LLC-based FRET is still wide open and highlypromising.

Cyclen-Based Lanthanide Complexes as Luminescent Anion Receptors by Luis M.P.Lima, Raphael Tripier (36-60).
This review highlights the research carried out during the last decade or so in the field of anion coordination usingcyclen-based lanthanide complexes as luminescent receptors (cyclen = 1,4,7,10-tetraazacyclododecane). Herein, thefundamental concepts explaining the particularly good affinity between cyclen derivatives and lanthanides and the way tosense the interaction with anionic substrates are firstly discussed. This is followed by a selection of examples from the recentliterature describing these cationic receptors as powerful optical sensors of environmental, biological and pharmaceuticalrelevance.

The long-lived f-centred luminescence of lanthanide chelates is of considerable interest for the development ofluminescent molecular probes in cellular imaging and bioassay and as dopants in light emitting devices. The intermetalliccommunication in molecular hetero-polymetallic compounds containing f and s or p block ions, d and f block ions and differentf-block ions opens up new avenues in FRET assays, directional light conversion, colour tuning and mixing, and thecombination of multiple molecular imaging techniques (e.g. optical-MRI) that, particularly when coupled with time-gatingprotocols, can eliminate competitive fluorescence from endogenous molecules. In all these applications, the focus remainson optimising the luminescence properties of the assemblies by directing the energy transfer processes involved. In thisshort review, an account of recent findings in the area of luminescent hetero-polymetallic lanthanide complexes is presented,focussing on the different synthetic strategies employed to construct s-f, p-f, d-f and f-f' arrays. An evaluation ofthe energy transfer processes and photophysical properties of this genre of compounds is provided, with specific emphasison potential applications.

Cation-Responsive MRI Contrast Agents Based on Gadolinium(III) by Goran Angelovski, Ilgar Mamedov (76-90).
Magnetic resonance imaging (MRI) offers the ability to visualize a number of biological processes at the molecularand cellular level. The quest for MRI methods that enable the monitoring of these processes with improved specificityand spatiotemporal resolution has induced a considerable amount of research into the chemistry of contrast agents.A novel class of agents has been developed that is able to report a change in its magnetic properties as a function of a specificparameter in the surrounding microenvironment. The vast majority consist of paramagnetic Gd3+ complexes that enhancethe contrast in the MR image upon a change in the local concentration of a biologically relevant ion, such as H+,Ca2+, Zn2+, or Cu2+. This review summarizes their coordination chemistry and further aspects of these responsive paramagneticcomplexes and discusses the most recent examples that are described in the literature.

Applications of Density Functional Theory (DFT) to Investigate the Structural, Spectroscopic and Magnetic Properties of Lanthanide(III) Complexes by Carlos Platas-Iglesias, Adrian Roca-Sabio, Martin Regueiro-Figueroa, David Esteban-Gomez, Andres de Blas, Teresa Rodriguez-Blas (91-116).
Density functional theory (DFT) has become a general tool to investigate the structure and properties of complicatedinorganic molecules, such as lanthanide(III) coordination compounds, due to the high accuracy that can beachieved at relatively low computational cost. Herein, we present an overview of different successful applications of DFTto investigate the structure, dynamics, vibrational spectra, NMR chemical shifts, hyperfine interactions, excited states, andmagnetic properties of lanthanide(III) complexes. We devote particular attention to our own work on the conformationalanalysis of LnIII-polyaminocarboxylate complexes. Besides, a short discussion on the different approaches used to investigatelanthanide(III) complexes, i. e. all-electron relativistic calculations and the use of relativistic effective core potentials(RECPs), is also presented. The issue of whether the 4f electrons of the lanthanides are involved in chemical bonding ornot is also shortly discussed.

Biomedical Applications of Nanomaterials Containing Gadolinium by Francois Lux, Stephane Roux, Pascal Perriat, Olivier Tillement (117-129).
The intense research activities devoted to nanoscience and nanotechnology led to the development of multifunctionalnanoparticles for biomedical applications and nanomedicine. By varying the size, the shape and the chemicalcomposition, the properties of these objects can be accurately controlled. As a result, nanoparticles can be designed forcombining several medical imaging techniques and therapy. Owing to their large range of properties, the lanthanides appearvery attractive for the elaboration of multifunctional nanoparticles for biomedical applications. The nanoparticles behaveas positive contrast agents for magnetic resonance imaging (MRI) when they contain gadolinium (III) and as negativecontrast if dysprosium (III) is present in the nanoparticles. The doping of gadolinium based nanoparticles by luminescentlanthanides (Eu3+, Tb3+) led to fluorescent and paramagnetic nanoparticles that can be detected both by MRI andfluorescence imaging. The synthesis and the functionalization of crystalline nanoparticles containing gadolinium (III)and/or other lanthanides are therefore very important for nanomedicine. This review gives an overview of selected developmentsand applications of such multifunctional nanoparticles.