Harnessing thermal waste with a poling-free molecular pyroelectric zinc(II) complex.

Transforming abundant thermal energy into electrical energy is an essential and sustainable solution to meet the rapidly growing global energy demand. In this communication, we report an electrical poling-free molecular complex [Zn(bpy)](ClO)·HO (1) with an appreciable pyroelectric coefficient value of 25 μC m K. This allowed us to harvest waste heat energy using a pyroelectric nanogenerator (PyG) device of 1, a relatively unexplored area for molecular complexes.

Structural insights into the initiation of free radical formation in the Class Ib ribonucleotide reductases in Mycobacteria.

Class I ribonucleotide reductases consisting of α and β subunits convert ribonucleoside diphosphates to deoxyribonucleoside diphosphates involving an intricate free radical mechanism. The generation of free radicals in the Class Ib ribonucleotide reductases is mediated by di-manganese ions in the β subunits and is externally assisted by flavodoxin-like NrdI subunit. This is unlike Class Ia ribonucleotide reductases, where the free radical generation is initiated at its di-iron centre in the β subunits with no external support from another subunit.

Nanoconfinement Effect in Water Processable Discrete Molecular Complex-Based Hybrid Piezo- and Thermo-Electric Nanogenerator.

Water-processable hybrid piezo- and thermo-electric materials have an increasing range of applications. We use the nanoconfinement effect of ferroelectric discrete molecular complex [Cu(l-phe)(bpy)(HO)]PF·HO () in a nonpolar polymer 1D-nanofiber to envision the high-performance flexible hybrid piezo- and thermo-electric nanogenerator (TEG). The 1D-nanoconfined crystallization of enhances piezoelectric throughput with a high degree of mechano-sensitivity, i.

Dianionic and Neutral Diboron-Centered Classical Diradicaloids.

Herein, we report the syntheses and electronic structures of crystalline dianionic as well as neutral diboron-centered classical diradicaloids as boron analogues of classical Thiele, Chichibabin, and Müller (this only for dianionic diradicaloids!) hydrocarbons. These are based on borane radical anion and NHC-stabilized boryl radical spin carriers, respectively. All these dianionic diboron-centered diradicaloids exhibit triplet population at room temperature regardless of the π-conjugated spacer: -phenylene, ,-biphenylene, or ,-terphenylene.

Deciphering the anisotropic energy harvesting responses of an above room temperature molecular ferroelectric copper(II) complex single crystal.

The mechanical/piezoelectric and/or thermal/pyroelectric energy harvesting efficiency is observed to be extremely good in multi-component ferroelectric inorganic oxides in their single-crystal form rather than in their polycrystalline counterparts (pellets and thick/thin films). However, growing such multi-component single crystals is a challenging and cost-intensive process besides the difficulty in tuning their long-range ferroic ordering and the involvement of toxic heavy elements. Instead, discrete inorganic metal complexes can be potential alternatives for which one can overcome these caveats by an appropriate design strategy.

Exploiting the Synergism of a Carbon-Catalyst Interface to Achieve Magneto-Electrocatalytic Overall Water Splitting at 2.197 V.

The desire to electrolyze water at low energy and high kinetics for achieving rapid H production forms the holy grail for the paradigm shift to a sustainable H-driven economy. While alkaline electrolysis is preferred due to the use of earth-abundant catalysts, its sluggish kinetics and high overpotential are the persistent challenges. Addressing this, we demonstrate the coupling of an externally applied magnetic field () to a synergistically designed interface of nanostructured carbon floret with antiferromagnetic NiO nanoflakes that act in unison to achieve rapid hydrogen generation (6.

Discrete Molecular Copper(II) Complex for Efficient Piezoelectric Energy Harvesting Above Room-Temperature.

Developing robust, wearable, and biocompatible energy harvesting devices with bulk oxides (ceramics and perovskites) is extremely hard to achieve due to their zero mechanical flexibility, heavy metal toxicity, and tunability of properties. Alternatively, discrete inorganic complexes can be an excellent choice to overcome the above-stated issues, thanks to appropriate molecular engineering. Herein, we report an above-room-temperature ferroelectric discrete molecular complex [Cu(L-phe)(bpy)(H O)]PF ⋅H O (1) which is suitable for piezoelectric energy harvesting due to its large values of piezoelectric co-efficient (d =10 pm V ) and spontaneous polarization (P =1.

Probing the Origin of Ferro-/Antiferromagnetic Exchange Interactions in Cu(II)-4f Complexes.

The mechanistic investigations between Cu(II) and the anisotropic lanthanides (Ln(III)) are not much explored to date. This is due to the complicated energy spectrum which arises due to the orbital angular momentum of anisotropic lanthanides. Interestingly, the exchange coupling in Ln(III)-Cu(II) systems was found to be antiferromagnetic for <4f metal ions and ferromagnetic for ≥4f metal ions, while the net magnitude of strength gradually decreases moving from to .

Role of Coordination Geometry on the Magnetic Relaxation Dynamics of Isomeric Five-Coordinate Low-Spin Co(II) Complexes.

To investigate the influence of the coordination geometry on the magnetization relaxation dynamics, two geometric isomers of a five-coordinate low-spin Co(II) complex with the general molecular formula [Co(DPPE)Cl]SnCl (DPPE = diphenylphosphinoethane) were synthesized and structurally characterized. While one isomer has a square pyramidal geometry (Co-SP ()), the other isomer figures a trigonal bipyramidal geometry (Co-TBP ()). Both complexes were already reported elsewhere.

Six-coordinated dinuclear lanthanide(III) amide complexes: investigation of magnetization relaxation dynamics and their electronic structures.

A series of rare six-coordinated dinuclear Ln(III) complexes [Ln(μ-Cl)ClLi(L)(THF)] were structurally characterized using a bulky amide ligand (L; Ln = Gd(1), Dy(2) and Y(3)). Detailed magnetic studies disclose that a weak antiferromagnetic coupling exists within 1 (-0.09 cm) and 2 (-0.

Quantifying magnetic anisotropy using X-ray and neutron diffraction.

In this work, the magnetic anisotropy in two iso-structural distorted tetrahedral Co(II) complexes, Co tmtu [ = Cl() and Br(), tmtu = tetra-methyl-thio-urea] is investigated, using a combination of polarized neutron diffraction (PND), very low-temperature high-resolution synchrotron X-ray diffraction and CASSCF/NEVPT2 calculations. Here, it was found consistently among all methods that the compounds have an easy axis of magnetization pointing nearly along the bis-ector of the compression angle, with minute deviations between PND and theory. Importantly, this work represents the first derivation of the atomic susceptibility tensor based on powder PND for a single-molecule magnet and the comparison thereof with calculations and high-resolution X-ray diffraction.

Magnetization relaxation dynamics of a rare coordinatively unsaturated Co(II) complex: experimental and theoretical insights.

A robust and unusual three coordinate Co(ii) complex [Li(DME)3][Co(L)3] (1, where L = Lithium (2,6-diisopropylphenyl) amide and DME = Dimethoxyethane) shows easy plane magnetic anisotropy (D) which is validated by variable temperature X-band EPR studies. 1 also registered with the largest anisotropic barrier (51.1 K, τ0 = 1.

Benzimidazole-based fluorophores for the detection of amyloid fibrils with higher sensitivity than Thioflavin-T.

Protein aggregation into amyloid fibrils is a key feature of a multitude of neurodegenerative diseases such as Alzheimer's, Parkinson's, and Prion disease. To detect amyloid fibrils, fluorophores with high sensitivity and better efficiency coupled with the low toxicity are in high demand even to date. In this pursuit, we have unveiled two benzimidazole-based fluorescence sensors ([C H N ] (C1) and [C H N O ] (C2), which possess exceptional affinity toward different amyloid fibrils in its submicromolar concentration (8 × 10  M), whereas under a similar concentration, the gold standard Thioflavin-T (ThT) fails to bind with amyloid fibrils.

Stabilizing Terminal Ni(III)-Hydroxide Complex Using NNN-Pincer Ligands: Synthesis and Characterization.

The reaction of [Ni(COD)] (COD; cyclooctadiene) in THF with the NNN-pincer ligand bis(imino)pyridyl (L) reveals a susceptibility to oxidation in an inert atmosphere ([O] level <0.5 ppm), resulting in a transient Ni:dioxygen adduct. This reactive intermediate abstracts a hydrogen atom from THF and stabilizes an uncommon Ni(III) complex.

The molecular and electronic structure of an unusual cobalt NNO pincer ligand complex.

The reaction of two equivalents of [Co(PMe)] (1) with one equivalent of a neutral NNO pincer ligand (L) led to the formation of purple-coloured single crystals. The crystal structure determination reveals the molecular structure as a cobalt dimer [Co(L)(PMe)], which is solved in the triclinic P1[combining macron] space group. Although this species appears to have a formal zero oxidation state on cobalt ions, careful analysis of the structural parameters of the L reveals that the NNO ligand is reduced by three electrons; this observation has rarely been reported in the literature.

Unusual Methylenediolate Bridged Hexanuclear Ruthenium(III) Complexes: Syntheses and Their Application.

Three structurally analogous hexanuclear ruthenium(III) complexes were isolated with the general molecular formula of [Ru(O)(μ-η-η-CHO)( t-BuCO)(L)] where L = pyridine (1) or 4-dimethylamino pyridine (DMAP; 2) or 4-cyanopyridine (3). Complexes 1 and 3 were solved in the tetragonal I4̅c2 and P422 space group, respectively, while 2 crystallized in the monoclinic system with P2 /c space group. In all three complexes, two oxo-centered Ru(III) triangles were bridged by a unique and a rare methylenediolate (CHO)) ligand.

Influence of Radicals on Magnetization Relaxation Dynamics of Pseudo-Octahedral Lanthanide Iminopyridyl Complexes.

Controlling quantum tunneling of magnetization (QTM) is a persistent challenge in lanthanide-based single-molecule magnets. As the exchange interaction is one of the key factors in controlling the QTM, we targeted lanthanide complexes with an increased number of radicals around the lanthanide ion. On the basis of our targeted approach, a family of pseudo-octahedral lanthanide/transition-metal complexes were isolated with the general molecular formula of [M(L)] (M = Gd (1), Dy (2), Er (3), Y (4)) using the redox-active iminopyridyl (L) ligand exclusively, which possess the highest ratio of radicals to lanthanide reported for discrete metal complexes.

Lanthanide-Based Porous Coordination Polymers: Syntheses, Slow Relaxation of Magnetization, and Magnetocaloric Effect.

Two lanthanide-containing structurally analogous porous coordination polymers (PCPs) have been isolated with the general molecular formula [Ln(L)(HO)(ox)] .4 nHO (where L = fumarate, ox = oxalate; Ln = Dy (1), Gd (2)). Thermogravimetric analysis (TGA) and TG-MS measurements performed on 1 and 2 suggest that not only the solvated water molecules in the crystal lattice but also the four coordinated water molecules on the respective lanthanides in 1 and 2 are removed upon activation.

Substituted versus Naked Thiourea Ligand Containing Pseudotetrahedral Cobalt(II) Complexes: A Comparative Study on Its Magnetization Relaxation Dynamics Phenomenon.

A series of mononuclear tetrahedral cobalt(II) complexes with the general molecular formula [Co(L)X] [where L = tetramethylthiourea ([(CH)N]C═S) and X = Cl (1), Br (2), and I (3)] were isolated, and their structures were characterized by single-crystal X-ray diffraction. The experimental direct-current magnetic data are excellently reproduced by fitting both χ T( T) and M( H) simultaneously using the spin Hamiltonian (SH) parameters D = -18.1 cm and g = 2.

Effect of coordination geometry on the magnetic properties of a series of Ln and Ln hydroxo clusters.

A series of three isostructural tetranuclear complexes with the general molecular formula [Ln(μ-OH)(L)(μ-piv)(MeOH)] (Ln = Gd 1, Dy 2 and Ho 3; LH = [1,3-bis(o-methoxyphenyl)-propane-1,3-dione]) were isolated and unambiguously characterized by single crystal XRD. Under similar reaction conditions, simply changing the co-ligand from pivalate to 2,6-bis(hydroxymethyl)-p-cresol (LH') led to the isolation of dinuclear Ln(iii) complexes with the general molecular formula [Ln(L)(μ-LH')]·4DMF (Ln = Gd 4, Dy 5 and Ho 6). Direct current magnetic susceptibility data studies on the polycrystalline sample of 1-6 and the results reveal the existence of weak antiferromagnetic exchange interactions between the lanthanide ions in 1 which is evident from the spin Hamiltonian (SH) parameters (J = -0.

Role of Halide Ions in the Nature of the Magnetic Anisotropy in Tetrahedral Co Complexes.

A series of mononuclear tetrahedral Co complexes with a general molecular formula [CoL X ] [L=thiourea and X=Cl (1), Br (2) and I (3)] were synthesized and their structures were characterized by single-crystal X-ray diffraction. Direct-current (dc) magnetic susceptibility [χ T(T) and M(H)] and its slow relaxation of magnetization were measured for all three complexes. The experimental dc magnetic data are excellently reproduced by fitting both χ T(T) and M(H) simultaneously with the parameters D=+10.

Role of the Diamagnetic Zinc(II) Ion in Determining the Electronic Structure of Lanthanide Single-Ion Magnets.

Four complexes containing Dy and Pr ions and their Ln -Zn analogs have been synthesized in order to study the influence that a diamagnetic Zn ion has on the electronic structure and hence, the magnetic properties of the Dy and Pr single ions. Single-crystal X-ray diffraction revealed the molecular structures as [Dy (HL) (NO ) ] (1), [Pr (HL) (NO ) ] (2), [Zn Dy (L) (CH CO )(NO ) ] (3) and [Zn Pr (L) (CH CO ) (NO )] (4) (where HL=2-methoxy-6-[(E)-phenyliminomethyl]phenol). The dc and ac magnetic data were collected for all four complexes.