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Creeping landslides may fail catastrophically, posing significant threats to infrastructure and lives. Landslides weaken over time through rock mass damage processes that may occur by steady‐state creep or transient accelerations of slip, called creep bursts. Creep bursts may control landslide stability by inducing short‐term damage and strain localization. This study focuses on the Åknes landslide in Norway, which moves up to 6 cm per year and could potentially trigger a large tsunami in the fjord below. An 11‐year data set is compiled and analyzed, including kinematic, seismic, and hydrogeological data acquired at the landslide surface and in a series of boreholes. An annual average of two creep bursts with millimeter amplitude has been recorded within the shear zone in each borehole, accounting for approximately 11% of the total displacement. Creep bursts detected simultaneously in multiple boreholes are preceded by increased seismic activity and rising water pressure. However, most creep bursts are observed in only one or a few boreholes. These bursts often happen during seasonal high and low groundwater levels in autumn and spring, respectively, correlating with local peaks in water pressure. No such correlation is observed during summer. We propose that creep bursts can have different causes and hypothesize that rock degradation leads to some creep bursts independent of water pressure variations. In contrast, the largest creep bursts are correlated with variations in absolute water pressure or gradients of water pressure within the shear zone. Our findings emphasize the complexity of a dense data set requiring multiple mechanisms to explain creep burst dynamics. Plain Language Summary: Slow‐moving landslides, advancing from millimeters to meters per year, can have strong destruction potential if they fail catastrophically. A landslide sliding plane weakens over time by rock crushing and fracturing. One of these processes is short‐lived movement accelerations that we call creep bursts. Creep bursts may control landslide stability by inducing short‐term damage and the development of a plane that allows the landslide to slide, which may lead to catastrophic failure. This study focuses on the Åknes landslide in Norway, which moves at 6 cm per year and could potentially trigger a great tsunami in the fjord below. Creep bursts with millimeter movements are detected at the landslide's sliding plane. Some creep bursts occur without water pressure changes at the initiation of the motion. These bursts are likely caused by the gradual crushing of the rock mass, independent of water level fluctuations. Conversely, the largest creep bursts are correlated with seasonal variations in groundwater level within the landslide. These larger bursts may be related to an easing of sliding by the absolute or the water pressure gradient. Our data set provides quantitative insights into transient slip accelerations, and these accelerations may be crucial in driving a large‐scale failure of the Åknes landslide. Key Points: We detected creep bursts on the shear zone of the Åknes landslide that accommodated 11% of the total displacementThe largest creep bursts are preceded by increased water pressure and microseismicity in the shear zoneMost of the creep bursts occur randomly over the year without correlation with other environmental parameters [ABSTRACT FROM AUTHOR]

One monometallic and three bimetallic ruthenium nitrosyl (RuNO) complexes are presented and fully characterized in reference to a parent monometallic complex of formula [FTRu(bpy)(NO)]3+, where FT is a fluorenyl‐substituted terpyridine ligand, and bpy the 2,2'‐bipyridine. These new complexes are built with the new ligands FFT, TFT, TFFT, and TF‐CC‐TF (where an alkyne C≡C group is inserted between two fluorenes). The crystal structures of the bis‐RuNO2 and bis‐RuNO complexes built from the TFT ligand are presented. The evolution of the spectroscopic features (intensities and energies) along the series, at one‐photon absorption (OPA) correlates well with the TD‐DFT computations. A spectacular effect is observed at two‐photon absorption (TPA) with a large enhancement of the molecular cross‐section (σTPA), in the bimetallic species. In the best case, σTPA is equal to 1523±98 GM at 700 nm, in the therapeutic window of transparency of biological tissues. All compounds are capable of releasing NO⋅ under irradiation, which leads to promising applications in TPA‐based drug delivery. [ABSTRACT FROM AUTHOR]

The massive worldwide deglaciation leads to more frequent slope instabilities in mountainous terrains. The physical processes leading to such destabilizations are poorly constrained due to little monitoring of dynamic parameters at the local scale. Here we study a very large slow‐moving landslide (∼0.8 km2), on the flank of Tungnakvíslarjökull glacier in Iceland. Based on a combination of remote sensing images, we monitor the landslide and glacier kinematics over 75 years, with a focus over the period 1999–2019 when rapid glacier wastage has been observed. The landslide accelerates from 2 to 45 m/yr in the 6 years following a sudden increase in glacier mass loss. This acceleration coincides with intense quake activity (Mℓ < 2.8), recorded by a regional seismic network. We show that this seismicity is caused by the landslide sliding on a rough surface. The evolution of the quake magnitudes suggests a progressive segmentation of the landslide mass during its acceleration. Plain Language Summary: Glacier‐retreat may lead to a destabilization of adjacent slopes that can evolve into large landslides. The time‐scales, as well as the controlling factors of the landslide response to this glacier retreat are poorly known, due to few observations of landslide dynamics in the vicinity of glaciers over the long term. To fill this gap, we document the dynamics of a large landslide in Iceland, developing on the flank of Tungnakvíslarjökull glacier, that underwent strong retreat after 1994. Based on aerial images since 1945 and satellite images since 1987, we calculate the motion of the landslide through time. We show that the landslide accelerated from 2 to 45 m/yr in the 6 years following the onset of glacier retreat. This acceleration coincides with earthquakes of small magnitudes (Mℓ < 2.8), produced by the landslide motion. Their analysis suggests that the landslide mass is progressively fragmented during the acceleration. This study opens interesting perspectives for landslide studies by combining seismic records from regional networks and 3D motions from satellites. Key Points: We monitor the dynamics of a very large slow‐moving landslide over 75 years, developing on the flank of a glaciated valleyThe landslide kinematics is strongly controlled by the glacier retreat, and produce seismicity correlated with the landslide velocityThe acceleration is linked with progressive segmentation of the landslide mass [ABSTRACT FROM AUTHOR]

Using the compound [RuII(FT)(bipy)(NO)](PF6)3 (FT is the electron- rich 4'-(2-fluorenyl)-2,2':6',2''-terpyridine ligand and bipy is 2-2'bipyridine) as a reference, two new compounds are presented in which carbon-carbon double and triple bonds are inserted between the fluorenyl substituent and the terpyridine to provide an extended conjugation path. The electronic properties of the three complexes are compared experimentally by UV-visible spectroscopy and computationally by means of the density functional theory. All of them exhibit a capability for NO release under irradiation on their low-energy transition located in the 400--500 nm range, with a quantum yield around 0.01. Their two-photon absorption (TPA) cross sections are investigated by the Z-scan technique at λ=800 nm. While the reference compound exhibits a cross-section equal to 108 GM, the introduction of double and triple bonds leads to increased cross-sections equal to 131 GM and 150 GM, respectively. These values are discussed in reference to the two-level model in use for "push-pull" dipolar TPA chromophores. [ABSTRACT FROM AUTHOR]

A set of BODIPY‐carboranyl dyads synthesized by a Sonogashira cross‐coupling reaction, where different C‐substituted ortho‐ and meta‐carboranyl fragments have been linked to a BODIPY fluorophore is described. Chemical, photophysical and physicochemical analyses are presented, including NMR and single XRD experiments, optical absorption/emission studies and partition coefficient (log P) measurements. These studies, supported by DFT computations (M06‐2X/6‐31G**), provide an explanation to the largely divergent cell income that these fluorescent carboranyl‐based fluorophores display, for which a structural or physicochemical explanation remains elusive. By studying the cell uptake efficiency and subcellular localization for our set of dyads on living HeLa cells, we tracked the origins of these differences to significant variations in their static dipole moments and partition coefficients, which tune their ability to interact with lipophilic microenvironments in cells. Remarkably, m‐carboranyl‐BODIPY derivatives with a higher lipophilicity are much better internalised by cells than their homologous with o‐carborane, suggesting that m‐isomers are potentially better theranostic agents for in vitro bioimaging and boron carriers for boron neutron capture therapy. [ABSTRACT FROM AUTHOR]

A one‐pot double condensation reaction between 3‐aminophenylboronic acid monohydrate and 2,6‐pyridincarboxyaldehyde forms the very interesting building block bisboronic dicationic acid (1), the reaction was carried out in methanol with the presence of sulfuric acid as catalyst. The product contains a central core consisting of five delocalized fused heterocycles being a dicationic moiety and including methylsulfate (CH3OSO3−) as anion (1a). Treatment with CaCl2 under heating produces the anion interchange leading the chloride as anion (1b). Both salts were crystallized by slow solvent evaporation and the X‐ray diffraction analysis reveals the presence of O−H⋅⋅⋅O hydrogen bonds favoring the 2D supramolecular arrangements. Three different motives were formed for 1a with the participation of water molecules, the methylsulfate anion and the boronic acid groups; by the way for 1b, the chloride anion interacts with a BOH group as well as a methanol molecule trough hydrogen bonds, additionally an electrostatic interactions were found with the cationic five membered rings. The possibility for syn‐anti isomerization at room temperature is confirmed by computations with a weak energy barrier of 17.7 kcal mol−1. [ABSTRACT FROM AUTHOR]

In mountainous environments, slow‐moving landslides (velocities <100 m/year) are a major concern for local populations. Rainfall is often the dominant forcing, and often result in major changes in kinematics which can mask smaller signals related to internal forcings. We focus here on a major (>40 Mm3) slow‐moving landslide in the desert of southern Peru and take advantage of this arid environment to study the internal processes affecting landslide kinematics. We first estimate the ground displacement from time series analysis of Landsat‐8 images, spanning a 5.7‐year period. Systematic artifacts in the optical time series are shown to correlate with topography, as well as vary seasonally. We apply a novel procedure for correcting these artifacts, which significantly reduces noise in the resulting time series, thereby allowing us to precisely resolve landslide displacements. We find landslide velocities of up to 35 m/year, with complex nonlinear interannual pattern, including a period of rapid acceleration. We validate our optically derived time series using Global Navigation Satellite System field measurements and find uncertainties (root‐mean‐square error) on the moving mass of 1.12 to 1.55 m. Sudden acceleration of the landslide body after March 2016 may originate from a mass collapse due to retrogression of the headscarp. By coupling sparse 3‐D Global Navigation Satellite System measurements with dense 2‐D optical time series data, we show that the headscarp retrogression acts like a wedge, resulting in domino‐like tilting of the downward blocks, and accelerates basal sliding over 2 years. These observations reveal that the dynamics of this retrogressive landslide are predominantly controlled by sediment supply and that succession of retrogressive and advancing motions is a self‐entrainment process. Key Points: Landsat‐8 images are used to measure a 5.7‐year‐long time series of displacement over a slow‐moving landslideA seasonal artifact in the Landsat‐8 images caused by illumination effects in steep topography is identified and correctedA retrogression of the landslide headscarp generates tilting and acceleration of the downward landslide mass [ABSTRACT FROM AUTHOR]

A ruthenium–nitrosyl derivative of formula [RuII(CzT)(bipy)(NO)](PF6)3 [CzT = 4′‐(N‐ethylcarbazol‐3‐yl)‐2,2′:6′,2′′‐terpyridine, bipy = 2,2′‐bipyridine] has been synthesized and fully characterized, and compared with the previously reported [RuII(FT)(bipy)(NO)](PF6)3 complex [FT = 4′‐(9,9‐dihexyl‐9H‐fluoren‐2‐yl)‐2,2′:6′,2′′‐terpyridine]. Additionally, the X‐ray crystal structure of [RuII(CzT)(bipy)(NO2)](PF6), the precursor of [RuII(CzT)(bipy)(NO)](PF6)3, is reported. The presence of a tertiary amine in the carbazole unit leads to redshifted charge‐transfer transitions towards the electron‐withdrawing Ru–NO fragment and hence enhanced two‐photon absorption (TPA) properties. In contrast, the quantum yield of the NO· photorelease process is lower for the carbazole‐containing complex. The issue of optimization of the TPA versus NO·‐release capabilities is addressed. [ABSTRACT FROM AUTHOR]

[RuII(FT)(bipy)(NO)][PF6]3 [FT is the electron-rich 4'-(2-fluorenyl)-2,2':6',2"-terpyridine ligand and bipy is 2,2'-bipyridine] is synthesized and characterized. It crystallizes in the triclinic P1 space group [a = 9.5362(2) Å, b = 10.3946(4) Å, c = 22.5701(8) Å, α = 94.7400(10)°, β = 94.9400(10)°, γ = 101.0680(10)]. A photochemical study is presented in comparison with that of the parents cis(Cl,Cl)-[RuII(FT)Cl2(NO)][PF6] and trans(Cl,Cl)-[RuII(FT)Cl2(NO)][PF6]. The three derivatives release nitric oxide (·NO) under irradiation at λ = 405 nm with respective quantum yields of 0.06, 0.31, and 0.10. Their two-photon absorption (TPA) cross-sections (sTPA) were investigated by the Z-scan technique on related derivatives in which two hexyl chains were introduced to improve their solubility while their spectroscopic properties remained almost unaffected. The resulting σTPA values of 100 GM at λ = 800 nm are in the window of transparency for human tissues, and the bipyridine-based complex exhibits a slight tendency for higher efficiency. The replacement of the [RuII(Cl)2(NO)] core by [RuII(bipy)(NO)] provides a much simpler synthesis, and the TPA-induced ·NO-release capabilities are in the same range of magnitude. Therefore, it is envisioned that ·NO donors of greater complexity with several metal centers could be investigated in future. [ABSTRACT FROM AUTHOR]

The large slow-moving landslide of Maca is located in the upper Colca valley (southern Peru), a region characterized by a well pronounced rainy period, and intense and recurrent sustained seismicity. The landslide, developed in deep lacustrine deposits, has recently accelerated, threatening the Maca village. This work aims at understanding the rupture mechanism and the causes of the recent landslide reactivation/acceleration. We present a multidisciplinary characterization of the Maca landslide that includes: (i) geological and morphological mapping in the field; (ii) remote sensing analysis using an historical aerial photograph of 1955 and the Pléiades satellite images (2013); (iii) global positioning system (GPS) including time-series of surveys over 13 years, and continuous measurements over 14 months; (iv) a geophysical campaign with deep electrical resistivity tomography profiles acquired across the landslide mass. Our study shows that this 60 Mm3 landslide, which can be classified as a clay/silt compound landslide, moved by 15 m between 2001 and 2014 with a large inter-annual velocity variation (up to a factor of 500) depending on the rainfall intensity. We suggest that these dramatic changes in velocity are the result of the combination of a threshold mechanism and the short intense rainy season in Peru. This study reveals three main driving factors acting at different timescales: (i) over several decades, the river course has significantly changed, causing the Maca landslide reactivation in the 1980s due to the erosion of its toe; (ii) at the year scale, a minimum amount of rainfall is required to trigger the motion and this amount controls the landslide velocity; (iii) transient changes in slide velocity may occur anytime due to earthquakes. This study particularly highlights the non-linear behaviour of the motion with rainfall. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Various attempts to combine magnetic and nonlinear optical (NLO) properties in a molecule are reviewed, with a special focus on the possibility of interplay between the magnetic component and the quadratic ([prop] E2) NLO response. This multidisciplinary research leads to the idea of spin-crossover-induced (SCO-induced) NLO switching and is evaluated at the synthetic level, with insights provided by computational chemistry. The need for nontraditional experimental setups to record NLO properties in the solid state is discussed. [ABSTRACT FROM AUTHOR]