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Efficient seismic risk assessment aids decision-makers in formulating citywide risk mitigation plans, providing insights into building performance and retrofitting costs. The complexity of modeling, analysis, and post-processing of the results makes it hard to fast-track the seismic probabilities, and there is a need to optimize the computational time. This research addresses seismic probability and risk assessment of reinforced concrete shear walls (RCSWs) by introducing stacked machine learning (Stacked ML) models based on Bayesian optimization (BO), genetic algorithm (GA), particle swarm optimization (PSO), and gradient-based optimization (GBO) algorithms. The study investigates 4-, to 15-Story RCSWs assuming different bay lengths and soil types to build a comprehensive database based on the incremental dynamic analysis (IDA) subjected to 56 near-field pulse-like and no-pulse records. Having 227,200 and 63,384 data points for a median of IDA curve (M IDA) and seismic probability curve, respectively, the proposed Stacked ML models have shown good performance on curve fitting ability by accuracy of 99.1% and 99.4% for M IDA and seismic fragility curves, respectively. In addition, the proposed models can estimate the mean annual frequency, λ , which is a key parameter in seismic risk assessment of buildings. To provide the results of the study for general buildings, a user-friendly GUI is proposed that facilitates result utilization, offering insights into seismic performance levels, providing the estimated M IDA and seismic failure probability curves, and mean annual frequency calculations for specific performance levels and seismic hazard curves. [ABSTRACT FROM AUTHOR]

The paper concerns the dynamic behavior of a simple slope model subjected to simultaneous horizontal and vertical excitations. The proposed method is based on Newmark's sliding block concept, however, four new features are introduced. The most important assumption is that the normal component of dynamic excitations affects the resisting force both before and after the initiation of the relative slope motion, making it time-dependent. The proposed formula and solution method is validated by experiments conducted on the shaking table and the bidirectional oscillatory device. The block displacement and acceleration time-histories are measured and analyzed. Experiments results conducted for bidirectional cyclic motion showed that the influence of vertical acceleration on the stability of the slope can be both negligible and significant (up to 57%). The numerical tests results, performed for thirty-five European seismic records, showed the underestimation of permanent displacement can reach up to 19% if the vertical excitation is neglected. • Horizontal excitation is dominant dynamic driving force causing slope slide. • Experiments confirmed effect of vertical acceleration on block behavior. • Inertia forces impact on resisting force increase permanent displacement by 30%. • Omitting vertical excitation may lead to underestimation of safety indicator by 19%. • Increasing peak vertical acceleration does not necessarily increase safety. [ABSTRACT FROM AUTHOR]

Structural pounding between adjacent, insufficiently separated buildings, or bridge segments, has been repeatedly observed during seismic excitations. Such earthquake-induced collisions may cause severe structural damage or even lead to the collapse of colliding structures. The aim of the present paper was to show the results of the study focused on determination of peak impact forces during collisions between buildings exposed to different seismic excitations. A set of different ground motion records, with various peak ground acceleration (PGA) values and frequency contents, were considered. First, pounding-involved numerical analysis was conducted for the basic parameters of colliding buildings. Then, the parametric study was carried out for different structural natural periods, structural damping ratios, gap sizes between buildings and coefficients of restitution. The results of the analysis conducted for the basic structural parameters indicate that the largest response of the analysed buildings was observed for the Duzce earthquake. The parametric study showed that the pounding-involved structural response depended substantially on all parameters considered in the analysis, and the largest response was observed for different ground motions. The results of the study presented in this paper indicate that the value of the peak impact force expected during the time of the earthquake does not depend on the PGA value of ground motion, but rather on the frequency contents of excitation and pounding scenario. It is therefore recommended that the peak impact force for buildings exposed to structural pounding during earthquakes should be determined individually for the specific structural configuration taking into account the design ground motion. [ABSTRACT FROM AUTHOR]

This study presents an innovative approach for the precise control of nodal displacements in pantographic structures. The method is founded on the Matrix Condensation of Force Method, seamlessly integrated with an Interior Point Optimization algorithm. This combination offers a unique advantage by allowing users to manipulate displaced nodes within a defined coordination domain. Furthermore, this approach introduces the Interior Point Optimization algorithm as an indispensable tool to eliminate inactive turnbuckles and minimize overall actuation requirements. Traditional control methods typically demand a substantial number of turnbuckles and extensive actuation efforts to attain the desired nodal coordinates. The interconnected nature of node movements, wherein changes in one node affect others, adds complexity to determining the impact of bar length alterations on each node. To address this challenge, precisely control power of the Interior Point Optimization algorithm systematically explores numerous scenarios to identify solutions that minimize both actuation and turnbuckle usage. The current technique's effectiveness is validated through rigorous comparisons with established methods, experimental modeling, and rigorous testing using SAP 2000 software. Notably, the current approach yields remarkable results, requiring a staggering 60% less actuation and reducing the reliance on turnbuckles by up to 40% compared to previous methods. This innovation promises to significantly enhance the efficiency and cost-effectiveness of controlling pantographic structures, marking a substantial advancement in this field. [Display omitted] • Existed and developed controlling equations are coupled with optimization algorithm. • Targeted displacements can be added as a domain. • The total actuation is minimized to up to 60%. • Inactive members are identified, number of turnbuckles is minimized. [ABSTRACT FROM AUTHOR]

Earthquake-induced pounding in bridges is a complex contact phenomenon in which the dynamic responses of structures, including collisions between deck and abutments, are strongly related to structural properties and earthquake excitation. The goal of this study is to develop and compare the seismic fragility curves of overall system and individual components of regular and irregular box-girder highway bridges in two cases: with pounding and without pounding. For this purpose, four levels of altitudinal irregularity, ranging from regular to highly irregular, are considered. To extend the results for all bridges in the same class, different sources of uncertainties related to earthquakes, structural geometries, and material properties are taken into account. The analytical fragility curves have been developed based on nonlinear time history analyses in OpenSees finite element software for the cases with and without pounding effects. The process has been repeated for each two-, three-, and four-span classes at four irregularity levels. The fragility function parameters for the two cases with and without pounding have been compared for all classes considered in this study. Using fragility functions, this paper clarifies the interactive roles of irregularity and pounding between deck and abutments for seismic vulnerability of multi-span box-birder highway bridges. The results indicate that collisions often show an adverse effect on all structural components. It has also been observed that the detrimental effect of pounding on seismic fragility is more apparent in irregular bridges when compared with regular ones. In addition, the study introduces a conversion coefficient to clarify the effects of pounding on the fragility of bridge components and the overall system. This coefficient can be applied in both conventional analytical methods like static or simplified analysis and technical earthquake models like HAZUS, adjusting fragility values for pounding and irregularity effects. [ABSTRACT FROM AUTHOR]

This paper uses the probabilistic seismic assessment to study the effects of pounding and irregularity on the seismic behavior of typical concrete box-girder bridges with four levels of altitudinal irregularity. To extend the results for all bridges in the same class, uncertainty related to the earthquake, structural geometries, and materials are considered. Pounding is likely to take place in two cases: the first one concerns the seat-type abutments, and the second is at the in-span hinge of multi-frame bridges. Accordingly, the present study is an attempt to investigate the behavior of irregular bridges considering the effects of pounding in both cases. In the first case, the effects of changes in the gap size on engineering demand parameters (EDPs) were investigated. Then, correlations between earthquake parameters and the pounding force were evaluated. Furthermore, the pounding force exerted on the abutment was compared for different bridge irregularity levels. In the second part of the paper, the effects of pounding of adjacent bridge segments in the decks of non-continuous bridges were studied for equivalent Two-Degree-of-Freedom structures, for which the probability of non-occurrence was estimated. In the end, the relationship between structural or seismic parameters and the pounding force was evaluated in case of pounding. The results of the study show that the gap size between the abutment and the deck has the highest effect on the abutment passive deformation, pounding force, and base shear. Also, the substructure irregularity of bridges reduces the correlation between the gap size and the EDPs, except for the column ductility. Moreover, decreasing the ratio of periods of the adjacent frames diminishes the effect of the type of the earthquake but increases the probability of pounding. [ABSTRACT FROM AUTHOR]

Cylindrical steel tanks are important components of industrial facilities. Their safety becomes a crucial issue since any failure may cause catastrophic consequences. The aim of the paper is to show the results of comprehensive FEM numerical investigation focused on the response of cylindrical steel tanks under mining tremors and moderate earthquakes. The effects of different levels of liquid filling, the influence of non-uniform seismic excitation as well as the aspects of diagnosis of structural damage have been investigated. The results of the modal analysis indicate that the level of liquid filling is really essential in the structural analysis leading to considerable changes in the shapes of vibration modes with a substantial reduction in the natural frequencies when the level of liquid increases. The results of seismic and paraseismic analysis indicate that the filling the tank with liquid leads to the substantial increase in the structural response underground motions. It has also been observed that the peak structural response values under mining tremors and moderate earthquakes can be comparable to each other. Moreover, the consideration of spatial effects related to seismic wave propagation leads to a considerable decrease in the structural response under non-uniform seismic excitation. Finally, the analysis of damage diagnosis in steel tanks shows that different types of damage may induce changes in the free vibration modes and values of natural frequencies. [ABSTRACT FROM AUTHOR]

The present research aims to study the influence of the soil–structure interaction (SSI) and existence or absence of masonry infill panels in steel frame structures on the earthquake-induced pounding-involved response of adjacent buildings. The study was further extended to compare the pounding-involved behavior versus the independent behavior of structures without collisions, focusing much on dynamic behavior of single frames. The effect of SSI was analyzed by assuming linear springs and dashpots at the foundation level. The infill panels were modeled using equivalent diagonal compression struts. The steel frames were assumed to have elastic–plastic behavior with 1% linear strain hardening. The dynamic contact approach was utilized to simulate pounding between the adjacent buildings. Nonlinear finite element analysis was performed for two adjacent multi-story structures with four different configurations representing cases that can exist in reality. The seismic response of the studied cases generally emphasized that ignoring the soil flexibility and/or the contribution of the infill panels may significantly alter the response of adjacent structures. This may result in a false expectation of the seismic behavior of buildings exposed to structural pounding under earthquake excitation. [ABSTRACT FROM AUTHOR]

Structural pounding has been observed in many previous earthquakes due to insufficient gap commonly provided between adjacent structures. The collisions usually generate large impact forces and short duration acceleration pulses which may result in significant damage to the colliding buildings. Because of that, earthquake-induced structural pounding has been intensively studied and investigated for the last three decades. Results of some of these investigations are compatible, whereas others contradict. This work reviews previous research studies concerning earthquake-induced structural pounding aiming to better understand pounding phenomenon itself and the reasons behind the contradictory results. The effect of pounding on buildings with fixed bases, isolated buildings, and buildings resting on soft soils are discussed. Then, aspects of a sufficient recommended gap are considered. Appropriate mitigation measures are also addressed and directions of the future research studies on structural pounding are recommended. • The main drawback of the present impact models is that the results depends, to a certain extent, on the impact model used. • The required seismic gap to prevent pounding proposed in seismic codes provide unconservative results in certain cases. • Some drawbacks face the proposed mitigation measures for structural pounding. [ABSTRACT FROM AUTHOR]

The aim of the present paper is to study the influence of the infill panels on the seismic pounding response of adjacent structures in series. The contribution of the masonry infill has been simulated using equivalent diagonal compression struts. Steel frames have been assumed to have elastic-plastic behavior with 1% linear strain hardening. The dynamic contact analysis has been utilized where contact surface model (target and contactor) has been applied without any connectors between the adjacent buildings. Nonlinear finite element analyses have been conducted on different configurations of infill distribution throughout the structures. The results of the analysis reveal that the existence of infill panels can substantially change the seismic behavior of the structures and may have a serious influence on their behavior during exposure to mutual pounding under seismic excitation. Moreover, the distribution of infill throughout the structure can significantly affect its behavior during earthquakes. [ABSTRACT FROM AUTHOR]

This paper describes a method to control the nodal displacement of prestressable truss structures within the desired domains. At the same time, the stress in all members is unleashed to take any value between the allowable tensile stress and critical buckling stress. The shape and stresses are controlled by actuating the most active members. The technique considers the members' initial crookedness, residual stresses, and slenderness ratio (S). Furthermore, the method is premeditated so that the members with an S between 200 and 300 can carry only tension before and after adjustment (i.e., the maximum compressive stress for the members with an S between 200 and 300 is zero). In addition, the derived equations are coupled with an optimization function that relies on five optimization algorithms (interior-point, trust-region-reflective, Sequential quadratic programming (SQP), SQP-legacy, and active-set). The algorithms identify and then exclude inactive actuators in the subsequent iterations. The technique is applied to several examples, and its results are compared with a quoted method in the literature. [ABSTRACT FROM AUTHOR]

• Parameter optimization improves system performance. • Average structural responses were significantly reduced compared to an uncontrolled structure. • The BI system showed the highest reduction in peak acceleration and inter-storey drift. • The BI-AFTMD system achieved the greatest reduction in peak displacement with average optimal parameters. • The proposed PID controller effectively enhanced seismic resilience. This study presents an innovative approach to mitigating seismic responses in multi-storey buildings equipped with a base-isolation (BI) system and passive friction-tuned mass dampers (PFTMDs). The key innovation lies in the combined use of a BI system and a PFTMD system, as well as the activation of this mechanical system by controllers. Additionally, the research design optimizes the parameters of these devices specifically for each earthquake scenario and compares the results to the average of the optimal parameters, which has not been investigated in previous studies. In this study, a 10-storey structure is modeled, featuring a BI system beneath the first floor and a PFTMD system on the roof. The parameters for the BI, PFTMD, BI-PFTMD, and BI-active FTMD (BI-AFTMD) systems are independently optimized using a multi-objective particle swarm optimization (MOPSO) algorithm. To enhance the passive BI-PFTMD system, a proportional-integral-derivative (PID) controller is incorporated into the friction-tuned mass damper system, resulting in the BI-AFTMD hybrid control system that adjusts the final control force transmitted to the structure. The seismic performance of these systems is assessed for the 10-storey building under both far-field and near-field earthquakes. The findings reveal that these control systems significantly decrease average peak displacement, acceleration, and inter-storey drift as compared to an uncontrolled structure, especially when system parameters are optimized for the same earthquake scenario. Using average optimal parameters, the BI-AFTMD system achieves the most substantial reduction in average peak displacement, while the BI system offers the greatest reduction in average peak acceleration and inter-storey drift. [ABSTRACT FROM AUTHOR]

This paper investigates the seismic behaviour of a five-storey shear building that incorporates a base isolation system. Initially, the study considers passive base isolation and employs a multi-objective archived-based whale optimization algorithm called MAWOA to optimize the parameters of base isolation. Subsequently, a novel model is proposed, which incorporates an interval type-2 Takagi-Sugeno fuzzy logic controller (IT2TSFLC) utilizing clustering techniques. The building includes Magneto-rheological (MR) dampers installed at the base isolation level and two active tendons positioned on the first and second storeys of the structure. The semi-active control force of the base isolation with MR dampers is determined by the fuzzy system, while the active control force for the active tendons is computed using the linear quadratic regulator (LQR) algorithm, enabling control force provision during seismic events. The primary objective of this model is to enhance the seismic control of the building. Therefore, it is classified as a proposed model. The structural system is subjected to seismic analyses, considering three different structural configurations: uncontrolled, equipped with passive base isolation, and equipped with semi-active base isolation combining MR dampers and active tendons. The findings of the research demonstrate that by considering the optimization of parameters of the passive base isolation based on the white noise scenario and using these parameters as design parameters, during seismic analysis of the structure in some earthquakes, increased structural responses were observed when compared to uncontrolled structure, highlighting a potential risk. Nevertheless, the proposed system effectively addresses this drawback of passive control systems by markedly reducing structural responses, as compared to both passive base isolation and uncontrolled structure. These results suggest that the proposed system is an effective solution for mitigating seismic risks in structural seismic control. • Implementation of IT2TSFLC controller based on clustering techniques with MR dampers in seismic-excited structure. • Executing an LQR controller to calculate the active control force of active tendons to enhance the seismic efficiency of the structure. • Optimization of passive base isolation under white noise excitation using the MAWOA algorithm. • The proposed system exhibits superior performance as compared to the passive system in reducing responses of the structure under various seismic excitations. • The proposed controller model consistently maintains its performance across all studied seismic events. [ABSTRACT FROM AUTHOR]

A major cause of local to total damages is related to structural pounding in a large number of past earthquakes. In general, these collisions take place as a result of differences in the dynamic characteristics of the colliding structures. To acquire a better perception of the behavior of structures, in this paper, three structures featuring different heights are modeled in series and with various configurations next to each other in OpenSees. To determine the collision effects of the structures, three different configurations of 4-, 8- and 12-story adjacent reinforced concrete special moment resisting frames were considered. Then, by conducting an incremental dynamic analysis, their structural seismic limit state capacities were assessed via 20 near-field record subsets recommended by FEMA-P695. At last, for the above adjacent buildings with various separation distances and configurations, the fragility curves were determined, and the probability of exceedance from the primary Hazus-MH failure criteria was estimated. In addition, the results were compared with those obtained when this phenomenon did not take place for buildings to have a better perception of the pounding phenomenon. The results of the analyses show that arranging adjacent structures in series greatly affects the collapse capacities of the colliding structures. In addition, in the case when the shorter structure is placed in the middle of two taller structures, it results in the most critical situation among all configurations, and in this case, a higher reduction is observed in the structural performance levels. [ABSTRACT FROM AUTHOR]

Architectural structures' nodal coordinates are significant to shape appearance; vertical overloading causes displacement of the joints resulting in shape distortion. This research aims to reshape the distorted shape of a double-layer spherical numerical model under vertical loadings; meanwhile, the stress in members is kept within the elastic range. Furthermore, an algorithm is designed using the fmincon function to implement as few possible actuators as possible to alter the length of the most active bars. Fmincon function relies on four optimization algorithms: trust-region reflective, active set, Sequential quadratic progra mming (SQP), and interior-point. The fmincon function is subjected to the adjustment technique to search for the minimum number of actuators and optimum actuation. The algorithm excludes inactive actuators in several iterations. In this research, the 21st iteration gave optimum results, using 802 actuators and a total actuation of 1493 mm.MATLAB analyzes the structure before and after adjustment and finds the optimum actuator set. In addition, the optimal actuation found in MATLAB is applied to the modeled structure in MATLAB and SAP2000 to verify MATLAB results. [ABSTRACT FROM AUTHOR]

• The effects of using linear and nonlinear Fluid Viscous Dampers (FVDs) for enhancing the seismic performance of adjacent colliding SMRFs and the median collapse capacities of them were investigated. • The modification factors were proposed to modify the median collapse capacity of a structure prone to earthquake-induced structural pounding. • Using linear or nonlinear FVDs can increase the median collapse capacities of adjacent structures exposed to pounding. • The modification factors can be successfully used to estimate the median collapse capacity of buildings without analytical difficulties. Severe damages of adjacent structures due to structural pounding during earthquakes have emphasized the need to use some seismic retrofit strategy to enhance the structural performance. The purpose of this paper is to study the influence of using linear and nonlinear Fluid Viscous Dampers (FVDs) on the seismic collapse capacities of adjacent structures prone to pounding and proposing modification factors to modify the median collapse capacity of structures considering the effects of pounding. The factors can be used to predict the collapse capacity of structures in pounding condition. A seismic retrofit strategy employs FVDs installed in 3-, 6- and 9-story Special Moment Resisting Frames (SMRFs). The SMRFs were assumed to have different values of separation distance according to the seismic code. To model pounding phenomenon, linear viscoelastic contact elements were used in the OpenSees software. Furthermore, to determine the seismic collapse capacities of each structure, the proposed algorithm was applied to remove the collapsed structure during the incremental dynamic analysis. The results of the analyses illustrate that the existence of FVDs can substantially improve the seismic behavior of structures having a significant influence on the collapse capacities of colliding structures. Moreover, considering the adjacent SMRFs in one or two sides of the main structure can significantly affect the median collapse capacity of the main structure itself. Finally, the proposed modification factors can be successfully used to estimate the effects of pounding on the collapse capacities of adjacent structures. [ABSTRACT FROM AUTHOR]

• The steel models with partially destroyed joints experience higher accelerations. • The steel models experience higher peak accelerations in the case of welded joints. • The steel models experience higher accelerations in the case of stiffened joints. • As the joints in the structure are more rigid, the acceleration at the top is higher. The aim of this paper is to study the response of models of steel buildings with destroyed and non-destroyed joints. The study was conducted experimentally using the shaking table tests. Two steel models were considered. Several types of joints were taken into account: totally destroyed joints, partially destroyed joints, welded joints and joints stiffened with additional metal. Six ground motions were taken into account. The acceleration time histories were measured at the top of these two models of steel buildings. The results of the study show that the steel models with partially destroyed joints experienced higher levels of accelerations at their top, as compared to the steel models with totally destroyed joints. It was also concluded that the steel models experienced higher peak accelerations at their top in the case of welded joints and stiffened joints, as compared to the case with totally destroyed joints and partially destroyed joints. [ABSTRACT FROM AUTHOR]

• A new approach is developed to map fragility curves of adjacent pounding steel moment-resisting frames through improved wavelet-based refined damage-sensitive feature considering higher mode contributions. • The acceleration responses to map fragility curves are based on wavelet-based refined damage-sensitive feature instead of spectral acceleration at the first mode period. • Fragility curves are developed by using cmor f b - f c wavelet-based damage-sensitive feature and refined damage-sensitive feature. • A more accurate probability of damages is obtained through cmor f b - f c wavelet-based refined damage-sensitive feature for moment-resisting frames with and without pounding effects. Fragility curves present useful information related to earthquake-induced probability assessment of steel moment-resisting frames (MRFs) and determine the probability of the damage exceedance at different floor levels of MRFs. The review of the literature shows that most of the previous studies dealing with the fragility curves were based on conventional measures, such as spectral acceleration at the first mode period, peak ground acceleration, and/or engineering demand parameters (e.g. maximum story drift ratio (max SDR)) to estimate the structure's damage state. In this article, a new approach is developed to map the fragility curves in adjacent MRFs including effects of pounding through improved wavelet-based refined damage-sensitive feature (WB-rDSF) which considers contributions of the upper modes. Morlet and complex Morlet (cmor f b - f c) wavelets, which is known as extremely precise rDSF, were extended to map the fragility curves. The correlation coefficient between rDSF and max SDR is evaluated as a criterion to determine the efficiency of wavelets-based damage index (WB-DI). The steel MRFs with six and nine stories are selected to implement the proposed approach concerning adjacent MRFs prone to structural pounding during earthquakes. Acceleration responses recorded at the roof of both colliding and non-colliding MRFs were determined using incremental dynamic analysis (IDA) including different seismic ground motion records to formulate the damage index. Moreover, the first mode structural period, used in assembling the WB-rDSF, is estimated via auto-regressive moving-average with exogenous input method along with a stabilization diagram. The results show that the fragility curves, derived from cmor f b - f c WB-rDSF for both colliding and non-colliding MRFs due to higher correlation coefficient, have lower damage probabilities and are more efficient than the estimated fragility curves based on Morlet WB-rDSF which consider only the structural period of the first mode. Furthermore, due to the pounding phenomenon, the lower MRF experiences more damages with a larger probability. [ABSTRACT FROM AUTHOR]

One of the pillars of the geometric approach to networks has been the development of model-based mapping tools that embed real networks in its latent geometry. In particular, the tool Mercator embeds networks into the hyperbolic plane. However, some real networks are better described by the multidimensional formulation of the underlying geometric model. Here, we introduce D-Mercator, a model-based embedding method that produces multidimensional maps of real networks into the (D + 1)-hyperbolic space, where the similarity subspace is represented as a D-sphere. We used D-Mercator to produce multidimensional hyperbolic maps of real networks and estimated their intrinsic dimensionality in terms of navigability and community structure. Multidimensional representations of real networks are instrumental in the identification of factors that determine connectivity and in elucidating fundamental issues that hinge on dimensionality, such as the presence of universality in critical behavior., (© 2023. The Author(s).)

Multifunctional materials, which exhibit diverse physical properties, are candidates for the new generation of smart devices that realize many tasks simultaneously. Particular attention is given to single-phase multifunctional materials that offer the new physical effects induced by the coupling between introduced properties. Complexes of lanthanide(3+) ions are an attractive source of multifunctionality since they combine luminescent functionalities related to their f-f or d-f electronic transitions with magnetic anisotropy that originates from spin-orbit coupling and crystal-field effects. The resulting luminescent single-molecule magnets (SMMs) link the area of functional luminophores, applicable in light-emitting diodes or sensing, with the field of molecular magnets, applicable for high-density data storage, and offer additional advantages, e.g. , fruitful magneto-optical correlations and the switching of emission by a magnetic field. It was recently shown that luminescent lanthanide SMMs can provide multifunctionality that is richly expanded towards their sensitivity to solvent exchange, temperature, or light, as well as the generation of electrical properties, such as super-ionic conductivity and ferroelectricity, or non-centrosymmetricity- and chirality-related effects, e.g. , second-harmonic generation and circularly polarized luminescence. Here, we discuss the pioneering reports on multifunctional materials that use luminescent lanthanide SMMs, with the emphasis of our contribution relying on the functionalization of 4f metal complexes through their insertion into heterometallic d-f coordination compounds.

The ab initio calculations were correlated with magnetic and emission characteristics to understand the modulation of properties of NIR-emissive [Yb III (2,2'-bipyridine-1,1'-dioxide) 4 ] 3+ single-molecule magnets by cyanido/thiocyanidometallate counterions, [Ag I (CN) 2 ] - ( 1 ), [Au I (SCN) 2 ] - ( 2 ), [Cd II (CN) 4 ] 2- /[Cd II 2 (CN) 7 ] 3- ( 3 ), and [M III (CN) 6 ] 3- [M III = Co ( 4 ), Ir ( 5 ), Fe ( 6 ), Cr ( 7 )]. Theoretical studies indicate easy-axis-type ground doublets for all Yb III centers. They differ in the magnetic axiality; however, transversal g -tensor components are always large enough to explain the lack of zero-dc-field relaxation. The excited doublets lie more than 120 cm -1 above the ground one for all Yb III centers. It was confirmed by high-resolution emission spectra reproduced from the ab initio calculations that give reliable insight into energies and oscillator strengths of optical transitions. These findings indicate the dominance of Raman relaxation with the power n varying from 2.93(4) to 6.9(2) in the 4 - 3 - 5 - 1 - 2 series. This trend partially follows the magnetic axiality, being deeper correlated with the phonon modes schemes of (thio)cyanido matrices.

Discrete molecular species that can perform certain functions in response to multiple external stimuli constitute a special class of multifunctional molecular materials called smart molecules. Herein, cyanido-bridged coordination clusters {[Fe II (2-pyrpy) 2 ] 4 [M IV (CN) 8 ] 2 }⋅4 MeOH⋅6 H 2 O (M=Mo (1 solv), M=W (2 solv) and 2-pyrpy=2-(1-pyrazolyl)pyridine are presented, which show persistent solvent driven single-crystal-to-single-crystal transformations upon sorption/desorption of water and methanol molecules. Three full desolvation-resolvation cycles with the concomitant change of the host molecules do not damage the single crystals. More importantly, the Fe 4 M 2 molecules constitute a unique example where the presence of the guests directly affects the pressure-induced thermal spin crossover (SCO) phenomenon occurring at the Fe II centres. The hydrated phases show a partial SCO with approximately two out-of-four Fe II centres undergoing a gradual thermal SCO at 1 GPa, while in the anhydrous form the pressure-induced SCO effect is almost quenched with only 15 % of the Fe II centres undergoing high-spin to low-spin transition at 1 GPa., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two new hexanuclear octahedral cyanido-bridged clusters, {[Cd II (bpy) 2 ] 4 [W IV (CN) 8 ] 2 }·10H 2 O (Cd 4 W 2 ) and {[Cd II (bpy) 2 ] 4 [Mo IV (CN) 8 ] 2 }·10H 2 O (Cd 4 Mo 2 ), have been obtained and characterized structurally and photomagnetically. Both compounds show a very rare and reversible single-crystal-to-single-crystal transformation upon dehydration accompanied by marked color changes in the case of Cd 4 W 2 . Moreover, irradiation of Cd 4 Mo 2 using 436 nm light induces a reversible photomagnetic effect due to the LIESST-like singlet-triplet transition at the Mo IV center. Analogous photomagnetic experiments for Cd 4 W 2 did not lead to any significant change of its magnetic moment.