Synergetic spin crossover and fluorescence in a mononuclear iron(III) complex.

Two mononuclear iron(III) complexes (XEA)[Fe(azp)]·HO (Hazp = 2,2'-azodiphenol, XEA = 2-fluoroethylammonium and 2-chloroethylammonium) are synthesized, which exhibit the counterion dependence of magnetic and fluorescent properties. The synergetic effect between abrupt spin crossover and fluorescence is observed in an iron(III) complex for the first time.

Two 2D spin-crossover coordination polymers constructed by [Pd(SCN)] building blocks.

Two new two-dimensional (2D) coordination polymers, [Fe(L){Pd(SCN)}] (L = 2-methoxypyrazine, 1; and L = ()-3-(phenyldiazenyl)pyridine, 2), were successfully constructed by using square-planar [Pd(SCN)] building blocks. Complex 1 exhibits complete and one-step spin-crossover (SCO) behavior, while 2 exhibits incomplete and two-step SCO behavior. Further structural insight into this synergy reveals that the flat/flexing [Fe{Pd(SCN)}] sheets in 1 and 2 are stabilized by interlayered/intralayered supramolecular interactions.

Integrating Polyoxometalate into Dy(III)-based Single-molecule Magnets with Pentagonal Bipyramidal Symmetry.

Polyoxometalates (POMs) with various coordination fashions are versatile ligands for constructing single-ion magnets (SIMs), but enforcing POM-SIMs with a specific geometry remains a synthetic challenge. Herein, we synthesized a POM-cocrystallized Dy-SIM [Dy(OPPh)(HO)][PWO]·4EtOH () and a POM-ligated Dy-SIM [{Dy(OPPh)(HO)}{PWO}]·PhPO·HO () with pentagonal bipyramidal local coordination geometry. Magnetic measurements indicate that displays field-induced single-molecule magnet (SMM) behavior and the relaxation is dominated by under-barrier processes.

Integrating Molecular Motions in Ternary Cocrystals for NIR-II Photothermal Conversion.

Organic photothermal conversion materials hold immense promise for various applications owing to their structural flexibility. Recent research has focused on enhancing near-infrared (NIR) absorption and mitigating radiative transition processes. In this study, we have developed a viable approach to the design of photothermal conversion materials through the construction of ternary organic cocrystals, by introducing a third component as a molecular blocker and motion unit into a binary donor-acceptor system.

Field-Induced Slow Magnetic Relaxation in Mononuclear Cobalt(II) Complexes Decorated by Macrocyclic Pentaaza Ligands.

Two cobalt(II) complexes [CoL](OTf) (, L = 6,6''-di(anilino)-4'-phenyl-2,2':6',2''-terpyridine) and [CoL](OTf)·MeOH (, L = 6,6''-di(,-dimethylamino)-4'-phenyl-2,2':6',2''-terpyridine) were synthesized and characterized. Crystal structure analyses showed that the spin carries were coordinated by five N atoms from the neutral pentaaza ligands, forming distorted trigonal bipyramidal coordination environments. Ab initio calculations revealed large easy-axial anisotropy in complexes and .

Spin-State Control in Dysprosium(III) Metallacrown Magnets via Thioacetal Modification.

Integrating controllable spin states into single-molecule magnets (SMMs) enables precise manipulation of magnetic interactions at a molecular level, but remains a synthetic challenge. Herein, we developed a 3d-4f metallacrown (MC) magnet [DyNi(quinha)(sal)(py)](ClO) ⋅ 4HO (Hquinha=quinaldichydroxamic acid, Hsal=5-chlorosalicylaldehyde) wherein a square planar Ni is stabilized by chemical stacking. Thioacetal modification was employed via post-synthetic ligand substitutions and yielded [DyNi(quinha)(saldt)(py)](ClO) ⋅ 3HO (Hsaldt=4-chloro-2-(1,3-dithiolan-2-yl)phenol).

Two-dimensional spin-crossover coordination polymers based on the 1,1,2,2-tetra(pyridin-4-yl)ethene ligand.

A series of two-dimensional (2D) spin-crossover coordination polymers (SCO-CPs) [Fe(TPE)(NCX)]·solv (1: X = BH, solv = HO·2CHOH·DMF; 2: X = Se, solv = HO·2CHOH·0.5DMF; 3: X = S, solv = HO·2CHOH·0.5DMF) were synthesized by employing 1,1,2,2-tetra(pyridin-4-yl)ethene (TPE) and pseudohalide (NCX) coligands.

Radical-Induced Photochromic Silver(I) Metal-Organic Frameworks: Alternative Topology, Dynamic Photoluminescence and Efficient Photothermal Conversion Modulated by Anionic Guests.

Photogenerated radicals are an indispensable member of the state-of-the-art photochromic material family, as they can effectively modulate the photoluminescence and photothermal conversion performance of radical-induced photochromic complexes. Herein, two novel radical-induced photochromic metal-organic frameworks (MOFs), [Ag(TEPE)](AC) ⋅ /HO ⋅ /EtOH (1) and [Ag(TEPE)](NC) ⋅ 3HO ⋅ EtOH (2), are reported. Distinctly different topological networks can be obtained by judiciously introducing alternative π-conjugated anionic guests, including a new topological structure (named as sfm) first reported in this work, describing as 4,4,4,4-c net.

Single-Crystal Transformation Engineering the Spin Change of Metal-Organic Frameworks via Cluster Deconstruction.

Spin crossover (SCO) materials with new architectures will expand and enrich the research in the SCO field. Here, we report two metal-organic frameworks (MOFs) containing tetradentate organic ligands and hexatopic linkers [Ag X (CN) ] (X=Br and I), which represents the first SCO MOF with clusters as building blocks. The silver halide cluster can be further removed after reacting with lithium tetracyanoquinodimethan (LiTCNQ).

High-stability spherical lanthanide nanoclusters for magnetic resonance imaging.

High-nuclear lanthanide clusters have shown great potential for the administration of high-dose mononuclear gadolinium chelates in magnetic resonance imaging (MRI). The development of high-nuclear lanthanide clusters with excellent solubility and high stability in water or solution has been challenging and is very important for expanding the performance of MRI. We used -methylbenzimidazole-2-methanol (HL) and LnCl·6HO to synthesize two spherical lanthanide clusters, Ln (Ln = Ho, Ho; and Ln = Gd, Gd), which are highly stable in solution.

Dynamic Magnetic Properties of Germole-ligated Lanthanide Sandwich Complexes.

The first germole-ligated single-molecule magnets are reported, with contrasting properties found for the near-linear sandwich complexes [(η -COT)Ln(η -Cp ] , where Ln=Dy (1 ) or Er (1 ), COT is cyclo-octatetraenyl and Cp is [GeC -2,5-(SiMe ) -3,4-Me ] . Whereas 1 has an energy barrier of 120(1) cm in zero applied field and open hysteresis loops up to 10 K, the relaxation in 1 is characterized by quantum tunneling within the ground state.

Magnetic and Luminescent Dual Responses of Photochromic Hexaazamacrocyclic Lanthanide Complexes.

Herein, hexaazamacrocyclic ligand L was employed to construct a series of photochromic rare-earth complexes, [Ln(L)(NO)](BPh) [, Ln = Dy, Tb, Eu, Gd, Y; L = (3,5,10,12)-3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane-3,5,10,12-tetraene]. The behavior of photogenerated radicals of hexaazamacrocyclic ligands was revealed for the first time. Upon 365 nm light irradiation, complexes exhibit photochromic behavior induced by photogenerated radicals according to EPR and UV-vis analyses.

Redox-Programmable Spin-Crossover Behaviors in a Cationic Framework.

Metal-organic frameworks (MOFs) provide versatile platforms to construct multi-responsive materials. Herein, by introducing the neutral tetradentate ligand and the linear dicyanoaurate(I) anion, we reported a rare cationic MOF [Fe(TPB){Au(CN)}]I·4HO·4DMF (TPB = 1,2,4,5-tetra(pyridin-4-yl)benzene) with hysteretic spin-crossover (SCO) behavior near room temperature. This hybrid framework with an open metal site (Au) exhibits redox-programmable capability toward dihalogen molecules.

Single-Crystal to Single-Crystal Transformation of a Spin-Crossover Hybrid Perovskite via Thermal-Induced Cyanide Linkage Isomerization.

Linkage isomers involving changes in the bonding mode of ambidentate ligands have potential applications in data storage, molecular machines, and motors. However, the observation of the cyanide-linkage-isomerism-induced spin change (CLIISC) effect characterized by single-crystal X-ray diffraction remains a considerable challenge. Meanwhile, the high-spin and low-spin states can be reversibly switched in spin-crossover (SCO) compounds, which provide the potential for applications to data storage, switches, and sensors.

Reversible Switchability of Magnetic Anisotropy and Magnetodielectric Effect Induced by Intermolecular Motion.

Introducing magnetic switchability into artificial molecular machines is fascinating for precise control of magnetism via external stimuli. Herein, a field-induced Co single-molecule magnet was found to exhibit the reversible switch of Jahn-Teller distortion near room temperature, along with thermal conformational motion of the 18-crown-6 rotor, which pulls the coordinated H O to rotate through intermolecular hydrogen bonds and triggers a single-crystal-to-single-crystal phase transition with T =282 K and T =276 K. Interestingly, the molecular magnetic anisotropy probed by single-crystal angular-resolved magnetometry revealed the reorientation of easy axis by 14.

Optimal guaranteed cost intermittent control to the efficient movement of freight trains.

Freight train system is under constant pressure to optimize operational efficiency, a factor that has led the sector to spearhead many new technologies. To address this, the optimal guaranteed cost intermittent cruise control of freight train system with time-varying uncertain parameters is investigated. In particular, the guaranteed cost intermittent control approach is proposed, which can achieve both advantages of guaranteed cost control and intermittent control methods.

Guest-Driven Light-Induced Spin Change in an Azobenzene Loaded Metal-Organic Framework.

Stimuli-responsive materials that can be reversibly switched by light are of immense interest. Among them, photo-responsive spin crossover (SCO) complexes have great promises to combine the photoactive inputs with multifaceted outputs into switchable materials and devices. However, the reversible control the spin-state change by photochromic guests is still challenging.

SADRNet: Self-Aligned Dual Face Regression Networks for Robust 3D Dense Face Alignment and Reconstruction.

Three-dimensional face dense alignment and reconstruction in the wild is a challenging problem as partial facial information is commonly missing in occluded and large pose face images. Large head pose variations also increase the solution space and make the modeling more difficult. Our key idea is to model occlusion and pose to decompose this challenging task into several relatively more manageable subtasks.

Tuning luminescence of didysprosium single-molecule magnets with a π-conjugated/non-conjugated bridging ligand.

Herein, we reported two didysprosium single-molecule magnets constructed with {Dy(bbpen)(MeOH)} subunits and a π-conjugated tpb or non-conjugated tpcb bridging ligand. The former exhibits extremely weak luminescence that makes it difficult to simulate its emission spectra. However, the later shows obviously enhanced and well-resolved luminescence, which helps us to gain knowledge about the magneto-optical correlation and the relevant magnetic energy levels.

Physical stimulus and chemical modulations of bistable molecular magnetic materials.

Manipulating bistability at the molecular level, especially in single-molecule magnet (SMM) and spin-crossover (SCO) materials, has attracted enormous recent interest due to their multifaceted magnetic behaviour and potential applications in devices. Moreover, their fascinating properties can be further modulated via chemical modifications and external stimuli, bringing about vast possibilities and valuable lessons. In this Feature Article, we present a selection of our research into this topic, as well as some other related achievements that have been made in recent years.

Slow magnetic dynamics in centrosymmetric didysprosium and equilateral triangular tridysprosium molecules.

Single-molecule magnets (SMMs) with higher nuclearity provide opportunity for understanding the inherent nature of magnetic dynamics that are not limited to mononuclear SMMs. Herein, centrosymmetric [Dy2(L)2(9-AC)4(MeOH)2]·2CH2Cl2·2H2O (1, where 9-AC = anthracene-9-carboxylate) and equilateral triangular [Dy3(OH)(OMe)(L)3(dbm)3](OH)·3CH2Cl2·7H2O (2, where dbm = dibenzoylmethane anion) were isolated using the Schiff-base ligand 4-(anthracen-9-yl)-2-((quinolin-8-ylimino)methyl)phenol (HL). Static and dynamic magnetic measurements reveal that 1 and 2 display slow magnetic relaxation under zero and applied dc field, respectively.

A square antiprism dysprosium single-ion magnet with an energy barrier over 900 K.

Herein we report a stable and high-performance Dy(iii) single-ion magnet (SIM) showing an energy barrier of 944 K under zero dc field, with an open hysteresis loop up to 6 K. To the best of our knowledge, this is the highest energy barrier for a square antiprism as well as phosphine oxide based Dy-SIMs, reported so far.

Slow magnetic relaxation in a {EuCu} metallacrown.

A 3d-4f heterometallic metallacrown with formula of [EuCu(quinha)(sal)(py)]CFSO·py·3HO (1) (Hquinha = quinaldichydroxamic acid; Hsal = salicylaldehyde) has been synthesized. This complex shows field-induced slow magnetic relaxation via a Raman-like process, where studies of the isostructural {LuCu} (2) and {YCu} (3) complexes show that the slow dynamics mainly arise from the {Cu} S = 1/2 ground state rather than the Eu ion. However, the Eu ion enhances the relaxation rates of the {Cu} unit which likely arises from second-order effects in the formally diamagnetic F ground state of Eu.