The continued increase in the atmospheric concentration of carbon dioxide due to anthropogenic emissions is predicted to lead to significant changes in climate. About half of the current emissions are being absorbed by the ocean and by land ecosystems, but this absorption is sensitive to climate as well as to atmospheric carbon dioxide concentrations, creating a feedback loop. General circulation models have generally excluded the feedback between climate and the biosphere, using static vegetation distributions and CO2 concentrations from simple carbon-cycle models that do not include climate change. Here we present results from a fully coupled, three-dimensional carbon–climate model, indicating that carbon-cycle feedbacks could significantly accelerate climate change over the twenty-first century. We find that under a 'business as usual' scenario, the terrestrial biosphere acts as an overall carbon sink until about 2050, but turns into a source thereafter. By 2100, the ocean uptake rate of 5 Gt C yr-1 is balanced by the terrestrial carbon source, and atmospheric CO2 concentrations are 250 p.p.m.v. higher in our fully coupled simulation than in uncoupled carbon models, resulting in a global-mean warming of 5.5 K, as compared to 4 K without the carbon-cycle feedback.

/pdf/acceleration-of-global-warming-due-to-carbon-cycle-feedbacks-3788793i7v.pdf

Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model

Lanthanide ions possess fascinating optical properties and their discovery, first industrial uses and present high technological applications are largely governed by their interaction with light. Lighting devices (economical luminescent lamps, light emitting diodes), television and computer displays, optical fibres, optical amplifiers, lasers, as well as responsive luminescent stains for biomedical analysis, medical diagnosis, and cell imaging rely heavily on lanthanide ions. This critical review has been tailored for a broad audience of chemists, biochemists and materials scientists; the basics of lanthanide photophysics are highlighted together with the synthetic strategies used to insert these ions into mono- and polymetallic molecular edifices. Recent advances in NIR-emitting materials, including liquid crystals, and in the control of luminescent properties in polymetallic assemblies are also presented. (210 references.)

Taking advantage of luminescent lanthanide ions

Self-Assembly of Discrete Cyclic Nanostructures Mediated by Transition Metals

The development in the field of coordination polymers or metal-organic coordination networks, MOCNs (metal-organic frameworks, MOFs) is assessed in terms of property investigations in the areas of catalysis, chirality, conductivity, luminescence, magnetism, spin-transition (spin-crossover), non-linear optics (NLO) and porosity or zeolitic behavior upon which potential applications could be based.

/pdf/engineering-coordination-polymers-towards-applications-3joywh2v74.pdf

Engineering coordination polymers towards applications

This report describes a number of substructural features which can help to identify compounds that appear as frequent hitters (promiscuous compounds) in many biochemical high throughput screens. The compounds identified by such substructural features are not recognized by filters commonly used to identify reactive compounds. Even though these substructural features were identified using only one assay detection technology, such compounds have been reported to be active from many different assays. In fact, these compounds are increasingly prevalent in the literature as potential starting points for further exploration, whereas they may not be.

/pdf/new-substructure-filters-for-removal-of-pan-assay-3e3dudtvn0.pdf

New Substructure Filters for Removal of Pan Assay Interference Compounds (PAINS) from Screening Libraries and for Their Exclusion in Bioassays

Helicates as Versatile Supramolecular Complexes.

The dinucleating ligand bis[ 1- methyl-2-(6'- [ 1”-(3,5 imethoxybenzyl)benzimidazol-2~'-ylp]y rid-2'-y1)benzimidazol- 5-yllmethane (L) reacts with lanthanide perchlorates to give dinuclear 2:3 complexes [Lnz(L)#+ (Ln = La, Eu, Gd, Tb, and Lu). Detailed ES-MS, lH-NMR, luminescence, and spectrophotometric measurements in acetonitrile show that the cations [Ln2(L)#+ are produced by strict self-assembly and adopt a triple-helical structure in solution (pseudo-D3s ymmetry). The crystal structure of [EU~(L)~] C~O~)~((1C1H, E~UC2NC1)9s~H 177N39036_Cl6,a = 17.634- (3) A, b = 21.408(4) A, c = 29.437(7) A, a = 82.13(1)', /3 = 85.76(1)', y = 89.79(1)', triclinic, P1, Z = 2) shows a dinuclear pseudo-D3 triple- elical cation, [Eu2(L)#+, where the three bis(terdentate) ligands L are wrapped around the helical axis defined by the europium atoms. The Eu(II1) of each site is 9-coordinated by six nitrogen atoms of the benzimidazole units occupying the vertices and three nitrogen atoms of the pyridine units occupying the capping positions of a slightly distorted, tricapped trigonal prism. Luminescence studies of the crystalline complex [Eu~(L)~]- (ClO.n n = 2, solv = H20,6; n = 9, solv = H20,7) confirm the pseudo-D3 symmetry of the Eu(II1) sites in 11 and show that secondary interactions with water molecules in 6 and 7 destroy the trigonal symmetry. An efficient intramolecular energy transfer between the %A* excited state centered on L and the excited levels of Eu(II1) and Tb(II1) is observed (antenna effect) together with a dipole4ipolar Tb - Eu intramolecular energy transfer in the heterodinuclear-doped Eu-Tb compound. Stability constants and 1H NMR in acetonitrile show that the homodinuclear complexes [LI I ~ (L) ~ ]a~re+ l ess stable for the heavier lanthanides Tb and Lu. The origin of this effect is discussed together with the nonstatistical distribution of the different species observed when stoichiometric quantities of L (3 equiv) are mixed with Ln1(C104)3 (1 equiv) and L I I ~ ( C ~ O(1~ e)q~ui v) in solution (Ln1 # Ln2; Ln1 = La, Eu, Tb, and Lu; Ln2 = Tb and Lu).

Self-assembly and photophysical properties of lanthanide dinuclear triple-helical complexes

Recently, linear ion traps (LITs) have been combined with quadrupole (Q), time-of-flight (TOF) and Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS). LITs can be used either as ion accumulation devices or as commercially available, stand-alone mass spectrometers with MSn capabilities. The combination of triple quadrupole MS with LIT technology in the form of an instrument of configuration QqLIT, using axial ejection, is particularly interesting, because this instrument retains the classical triple quadrupole scan functions such as selected reaction monitoring (SRM), product ion (PI), neutral loss (NL) and precursor ion (PC) while also providing access to sensitive ion trap experiments. For small molecules, quantitative and qualitative analysis can be performed using the same instrument. In addition, for peptide analysis, the enhanced multiply charged (EMC) scan allows an increase in selectivity, while the time-delayed fragmentation (TDF) scan provides additional structural information. Various methods of operating the hybrid instrument are described for the case of the commercial Q TRAP (AB/MDS Sciex) and applications to drug metabolism analysis, quantitative confirmatory analysis, peptides analysis and automated nanoelectrospray (ESI-chip-MS) analysis are discussed.

http://aether.cmi.ua.ac.be/artikels/MB_31655.pdf

Triple quadrupole linear ion trap mass spectrometer for the analysis of small molecules and macromolecules

To support pharmacokinetic and drug metabolism studies, LC-MS/MS plays more and more an essential role for the quantitation of drugs and their metabolites in biological matrices. With the new challenges encountered in drug discovery and drug development, new strategies are put in place to achieve high-throughput analysis, using serial and parallel approaches. To speed-up method development and validation, generic approaches with the direct injection of biological fluids is highly desirable. Column-switching, using various packing materials for the extraction columns, is widely applied. Improvement of mass spectrometers performance, and in particular triple quadrupoles, also strongly influences sample preparation strategies, which remain a key element in the bioanalytical process.

Quantitative high-throughput analysis of drugs in biological matrices by mass spectrometry.

The segmental ligand 2-{6-[N,N-diethylcarbamoyl]pyridin-2-yl}-1,1‘-dimethyl-5,5‘-methylene-2‘-(5-methylpyridin-2-yl)bis[1H-benzimidazole] (L2) reacts with stoichiometric amounts of Ln(III) (Ln = La−Nd, Sm−Tb, Tm−Lu, Y) and Zn(II) in acetonitrile to yield quantitatively and selectively the heterodinuclear triple-helical complexes [LnZn(L2)3]5+ under thermodynamic control. The crystal structure of [EuZn(L2)3](ClO4)(CF3SO3)4(CH3CN)4 (13; EuZnC111H111N25O19F12S4Cl, monoclinic, C2/c, Z = 8) shows the wrapping of the three ligands L2 about a pseudo-C3 axis passing through the metal ions. Zn(II) occupies the distorted pseudooctahedral capping coordination site defined by the three bidentate binding units while Eu(III) lies in the resulting “facial” pseudotricapped trigonal prismatic site produced by the three remaining tridentate units as exemplified by luminescence measurements using the Eu(III) structural probe. The separation of contact and pseudocontact contributions to the 1H-NMR paramagnetic shifts of the ...

Lanthanide Podates with Predetermined Structural and Photophysical Properties: Strongly Luminescent Self-Assembled Heterodinuclear d−f Complexes with a Segmental Ligand Containing Heterocyclic Imines and Carboxamide Binding Units

Gérard Hopfgartner

Papers

Helicates as Versatile Supramolecular Complexes.

Self-assembly and photophysical properties of lanthanide dinuclear triple-helical complexes

Triple quadrupole linear ion trap mass spectrometer for the analysis of small molecules and macromolecules

Quantitative high-throughput analysis of drugs in biological matrices by mass spectrometry.

Lanthanide Podates with Predetermined Structural and Photophysical Properties: Strongly Luminescent Self-Assembled Heterodinuclear d−f Complexes with a Segmental Ligand Containing Heterocyclic Imines and Carboxamide Binding Units