Tipping the balance between and ligand conformers in multinuclear ethylzinc cyclophosphazenates.

Hexaanionic cyclophosphazenate ligands [(RN)PN] provide versatile platforms for the assembly of multinuclear metal arrays due to their multiple coordination sites and highly flexible ligand core structure. This work investigates the impact of incrementally increasing the steric demand of the ligand periphery on the coordination behavior of ethylzinc arrays. It shows that the increased congestion around the ligand sites is alleviated by progressive condensation with the elimination of diethylzinc.

A Chiral Hexa-amino Cyclotriphosphazene for Enantioselective Recognition of Small Organic Compounds.

Chiral recognition and separation studies are of paramount importance in research in view of their applications in asymmetric catalysis and substrate recognition in biological processes. The efficiencies of these processes are governed by the subtle differences in noncovalent interactions between the host and guest molecules. Hexakis(organoamino)phosphazenes are versatile building blocks for host-guest chemistry for their ability to act as both the donor and the acceptor of H-bonds.

Metal-free small molecule-based piezoelectric energy harvesters.

Organic and metal-free molecules with piezoelectric and ferroelectric properties have gained wide interest for their applications in the domain of mechanical energy harvesting due to their desirable properties such as light weight, thermal stability, mechanical flexibility, feasibility to achieve high Curie temperatures, and ease of synthesis. However, the understanding and design of these materials for piezoelectric energy harvesting applications is still in its early stages. This review paper presents a comprehensive overview of the fundamental characterization of piezoelectricity for a range of organic ferro- and piezoelectric materials and their composites.

Ligand-Directed Synthesis of a Self-Organized Chloro-Bridged Cubic Pd(II) Cage Showing Selective Encapsulation of Phenols.

The synthesis and guest recognition properties of a neutral Pd-cubic cage, [{Pd(NPr)PO}(μ-Cl)] 1 are reported. The formation of the cubical assembly takes place by an exclusive one-pot ligand-assisted pathway directed by an oximido linker. The initial coordination of the oximido ligand pre-organizes the [Pd(NPr)PO] polyhedral building units into a tetrameric intermediate, which then transforms into an oximido-tethered tetrahedral assembly and to the cubical cage 1 in the presence of chloride ions.

A Highly Electrostrictive Salt Cocrystal and the Piezoelectric Nanogenerator Application of Its 3D-Printed Polymer Composite.

Ionic cocrystals with hydrogen bonding can form exciting materials with enhanced optical and electronic properties. We present a highly moisture-stable ammonium salt cocrystal [CHCHCH(CH)NH][CHCHCH(CH)NH][PF] () crystallizing in the polar monoclinic 2 space group. The asymmetry in was induced by its chiral substituents, while the polar order and structural stability were achieved by using the octahedral PF anion and the consequent formation of salt cocrystal.

Ferroelectric Organic-Inorganic Hybrid Ammonium Halogenobismuthate(III) for Piezoelectric Energy Harvesting.

Halogenobismuthate(III) compounds are of recent interest because of their low toxicity and distinct electrical properties. The utility of these materials as ferroelectrics for piezoelectric energy harvesters is still in its early stages. Herein, we report a hybrid ammonium halogenobismuthate(III) , crystallizing in a ferroelectrically active polar noncentrosymmetric 2 space group.

Squarate-Tethered Enantiomeric Imido-Pd(II) Cages for Recognition and Separation of Chiral Organic Molecules.

Chiral coordination cages have emerged as an efficient platform for enantioselective processes via host-guest interactions. Here, we report an enantiomeric pair of tetrahedral cages of formula [(Pd[PO(N(*CH(CH)Ph)])(CO)] supported by chiral tris(imido)phosphate trianions and squarate (CO) linkers. These cages exhibit unusual coordination isomerism for Pd(II)-linker bonds compared with the other Pd(II) cages of this family.

Design and Piezoelectric Energy Harvesting Properties of a Ferroelectric Cyclophosphazene Salt.

Cyclophosphazenes offer a robust and easily modifiable platform for a diverse range of functional systems that have found applications in a wide variety of areas. Herein, for the first time, it reports an organophosphazene-based supramolecular ferroelectric [(PhCH NH) P N Me]I, [PMe]I. The compound crystallizes in the polar space group Pc and its thin-film sample exhibits remnant polarization of 5 µC cm .

3D-printed polymer composite devices based on a ferroelectric chiral ammonium salt for high-performance piezoelectric energy harvesting.

Three-dimensional printing (3DP) is an emerging technology to fabricate complex architectures, necessary to realize state-of-the-art flexible and wearable electronic devices. In this regard, top-performing devices containing organic ferro- and piezoelectric compounds are desired to circumvent significant shortcomings of conventional piezoceramics, toxicity and high-temperature device processibility. Herein, we report on a 3D-printed composite of a chiral ferroelectric organic salt {[MeCCH(Me)NH][BF]} (1) with a biodegradable polycaprolactone (PCL) polymer that serves as a highly efficient piezoelectric nanogenerator (PENG).

Encapsulation Studies on -Dicarbadodecaborane Isomers in Neutral Tetrahedral Palladium(II) Cages.

The encapsulation of icosahedral -dicarbadodecaborane (-, -, and -carboranes, ) as guest molecules at the intrinsic cavities of the three isostructural tetrahedral cages [{Pd(NPr)PO}(Cl-AN)] (), [{Pd(NPr)PO}(Br-AN)] (), and [{Pd(NPr)PO}(H-AN)] () was studied. The formation of definite host-guest assemblies was probed with mass spectrometry, IR, and NMR spectral analysis. 2D DOSY H NMR of the ⊂Cage systems showed similar diffusion coefficient () values for the host and guest species, signifying the encapsulation of these guests inside the cage assemblies.

Visualization of domain structure and piezoelectric energy harvesting in a ferroelectric metal-ligand cage.

The ferroelectric behaviour of an octahedral cage [[Ni(HO)(TPTA)]·(NO)·36HO] (1) exhibiting high remnant polarization of 25.31 μC cm is discovered. For the first time, clear domain structures and the characteristic electromechanical responses are demonstrated using piezoresponsive force microscopy for a thin film of 1.

A Ferroelectric Aminophosphonium Cyanoferrate with a Large Electrostrictive Coefficient as a Piezoelectric Nanogenerator.

Hybrid materials possessing piezo- and ferroelectric properties emerge as excellent alternatives to conventional piezoceramics due to their merits of facile synthesis, lightweight nature, ease of fabrication and mechanical flexibility. Inspired by the structural stability of aminophosphonium compounds, here we report the first A BX type cyanometallate [Ph ( PrNH) P] [Fe(CN) ] (1), which shows a ferroelectric saturation polarization (P ) of 3.71 μC cm .

A bis-NHC-CAAC dimer derived dicationic diradical.

The isolation of carbon-centered diradicals is always challenging due to synthetic difficulties and their limited stability. Herein we report the synthesis of a -1,4-cyclohexylene bridged bis-NHC-CAAC dimer derived thermally stable dicationic diradical. The diradical character of this compound was confirmed by EPR spectroscopy.

Mapping the Assembly of Neutral Tetrahedral Cages Tethered by Oximido Linkers and Their Guest Encapsulation Studies.

A primary criterion for the design of polyhedral metal-organic cages is the requirement of geometrically matched pairs of metal ions and ligand moieties. However, understanding the pathway it takes to reach the final polyhedral structure can provide more insights into the self-assembly process and improved design strategies. In this regard, we report two neutral tetrahedral cages with the formulas {[Pd(NPr)PO](L)} () and {[Pd(NPr)PO](L)} () starting from the acetate-bridged cluster {[Pd(NPr)PO](OAc)(OH)}·2(CH)SO () and the respective oxamide precursors (LH: [C(NH)O]) and (LH: (C(NHMe)O]).

Efficient Piezoelectric Energy Harvesting from a Discrete Hybrid Bismuth Bromide Ferroelectric Templated by Phosphonium Cation.

Bismuth containing hybrid molecular ferroelectrics are receiving tremendous attention in recent years owing to their stable and non-toxic composition. However, these perovskite-like structures are primarily limited to ammonium cations. Herein, we report a new phosphonium based discrete perovskite-like hybrid ferroelectric with a formula [Me(Ph) P] [Bi Br ] (MTPBB) and its mechanical energy harvesting capability.

Growth of highly conducting MoSN thin films with enhanced 1T' phase by pulsed laser deposition and exploration of their nanogenerator application.

High-quality growth of MoSN films is realized on single-crystal -AlO substrates by the pulsed laser deposition (PLD) in ammonia rendering highly stable and tunable 1T'/2H biphasic constitution. Raman spectroscopy reveals systematic enhancement of 1T' phase component due to the incorporation of covalently bonded N-doping in MoS lattice, inducing compressive strain. Interestingly, the film deposited at 300 mTorr NH shows ∼80% 1T' phase.

Polyanionic Imido-P(V) Ligands: From Transition Metal Complexes to Coordination Driven Self-Assemblies.

The chemistry of the imido-anions of the main group elements has been studied for more than three decades. The imido (NR) group is isoelectronic to the oxo (=O) group and can coordinate with metal ions through its lone pairs of electrons. The polyimido-P(V) anions are well explored as they resemble the phosphorus oxo moieties such as H PO , H PO , HPO and PO species.

Ferroelectricity and Piezoelectric Energy Harvesting of Hybrid ABX-Type Halogenocuprates Stabilized by Phosphonium Cations.

Perovskite-structured compounds containing organic cations and inorganic anions have gained prominence as materials for next-generation electronic and energy devices. Hybrid materials possessing ferro- and piezoelectric properties are in recent focus for mechanical energy harvesting (nanogenerator) applications. Here, we report the ferroelectric behavior of ABX-type halogenocuprate materials supported by heteroleptic phosphonium cations.

A Flexible Energy Harvester from an Organic Ferroelectric Ammonium Salt.

Organic ferroelectrics due to their low cost, easy preparation, light weight, high flexibility and phase stability are gaining tremendous attention in the field of portable electronics. In this work, we report the synthesis, structure and ferroelectric behavior of a two-component ammonium salt 2, containing a bulky [Bn(4-BrBn)NMe ] (Bn=benzyl and 4-BrBn=4-bromobenzyl) cation and tetrahedral (BF ) anion. The structural analysis revealed the presence of rich non-classical C-H⋅⋅⋅F and C-H⋅⋅⋅Br interactions in this molecule that were quantified by Hirshfeld surface analysis.

Construction of Entropically Favored Supramolecular Metal-Ligand Trimeric Assemblies Supported by Flexible Pyridylaminophosphorus(V) Scaffolds.

The self-assembly reactions of tetratopic metal acceptors with the flexible bidentate ligands are known to yield self-assembled molecular squares of the type [ML], triangles of composition [ML], or a mixture of these two. In this work, we demonstrate the preferential formation of a trimeric cage assembly of the formula [Pd()·(BF)] () over the tetrameric cage [Pd()·(BF)] () by employing a flexible dipodal phosphoramide ligand, [PhPO(NH(3-Py))] (; 3-Py = 3-aminopyridine), in a reaction with [Pd(CHCN)·(BF)]. The entropically favored trimeric self-assembly of is the predominant species in the solution [dimethyl sulfoxide (DMSO)-] at room temperature.

Enantiopure Polyradical Tetrahedral Pd L Cages.

The synthesis of cages with a polyradical framework remains a challenging task. Herein is reported an enantiomeric pair of quinoid-bridged polyradical tetrahedral palladium(II) cages that are stabilized by an unusual dianionic diradical form (dhbq ). These cages have been characterized by electron paramagnetic resonance and UV-visible spectroscopy, squid magnetometry and mass spectrometry.

Effective Enantioselective Recognition by Chiral Amino-Phosphonium Salts*.

The research on chiral recognition and selection is not only fundamental in deciding the mystery of homochirality, but also informative in terms of substrate recognition in biological processes and asymmetric catalysis. We report an enantiomeric pair of phosphonium salts having chiral (R and S) amino substituents that are utilized towards the enantioselective recognition of a variety of chiral compounds having functional groups, such as carboxylic acid, amine, and alcohol. These simple phosphonium salts are found to exhibit a high enantiomeric discrimination for 1-cyclohexylethylamine (CY).

Ferroelectric Behavior of an Octahedral Metal-Ligand Cage and Its 2D-Connected Cage Framework.

Supramolecular systems hold great potential as ferroelectric materials because they are easy to prepare and do not require toxic and environmentally damaging elements. However, directing the self-assembly process of a supramolecular array to yield polarizable solids is still challenging. Here, we describe induced ferroelectricity in a supramolecular framework of metal-organic cages that are supported by a flexible tripodal ligand (NHCH -(3-Py)) PO (TPPA).

Piezoelectric Energy Harvesting from a Ferroelectric Hybrid Salt [Ph MeP] [Ni(NCS) ] Embedded in a Polymer Matrix.

Organic-inorganic hybrid ferroelectrics are an exciting class of molecular materials with promising applications in the area of energy and electronics. The synthesis, ferroelectric and piezoelectric energy harvesting behavior of a 3d metal ion-containing A BX type organic-inorganic hybrid salt [Ph MeP] [Ni(NCS) ] (1) is now presented. P-E hysteresis loop studies on 1 show a remnant ferroelectric polarization value of 18.