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The synthesis and guest recognition properties of a neutral Pd24‐cubic cage, [{Pd3(NiPr)3PO}8(μ2‐Cl)24] 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 [Pd3(NiPr)3PO]3+ 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. In the absence of the directing oximido linker, no cage formation was observed, and the Pd6‐precursor was found to undergo self‐condensation, giving rise to a new pentameric polyhedral cluster, [Pd5{(NiPr)3PO}2(OAc)2(OH)2] 2. The central cavity of the cube has been probed for guest encapsulation studies, which shows a high binding with phenolic guest molecules with association constants of the order of 104–105 M−1. The favorable formation of host–guest complexes was attributed to the strong hydrogen bonding interactions between the host and guest functional groups. [ABSTRACT FROM AUTHOR]

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. It also discusses the limitations of traditional piezoelectric materials and highlights the advantages of organic materials in this area in the introduction part. In addition, the paper provides a detailed description of peptide-based and other biomolecular piezoelectric materials as a bio-friendly alternative to current materials. This perspective aims to guide researchers in designing functional organic materials and composites for practical mechanical energy harvesting applications and to highlight current limitations and future perspectives in this emerging area of research. [ABSTRACT FROM AUTHOR]

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 A3BX6 type cyanometallate [Ph2(iPrNH)2P]3[Fe(CN)6] (1), which shows a ferroelectric saturation polarization (Ps) of 3.71 μC cm−2. Compound 1 exhibits a high electrostrictive coefficient (Q33) of 0.73 m4 C−2, far exceeding those of piezoceramics (0.034–0.096 m4 C−2). Piezoresponse force microscopy (PFM) analysis demonstrates the polarization switching and domain structure of 1 further confirming its ferroelectric nature. Furthermore, thermoplastic polyurethane (TPU) polymer composite films of 1 were prepared and employed as piezoelectric nanogenerators. Notably, the 15 wt % 1‐TPU device gave a maximum output voltage of 13.57 V and a power density of 6.03 μW cm−2. [ABSTRACT FROM AUTHOR]

Metal-organic hybrid supramolecular architectures based on lighter transition metal ions are an emerging class of ferroelectric materials due to their highly crystalline nature and less toxicity. However, synthesizing polar metal-ligand assemblies is still challenging as well-defined design strategies are unknown for obtaining these crystalline solids in non-centrosymmetric structures. Herein, we report a new discrete octahedral metal-organic cage [Cu6(TPPA)8(H2O)12]·(NO3)12·32H2O] (1) by employing a tripodal phosphoramide ligand, [PO(NH3Py)3] (TPPA). Ferroelectric measurements on 1 showed improved polarization vs. the electric field (P-E) hysteresis loop characteristics than those observed for similar cages, with a sizable remnant polarization (Pr) value of 39.2 µC/cm2. The non-centrosymmetric structure of 1 can be tracked to the uniform rotation of the octahedra around the metal centre. At the same time, the polarization in the framework stems from the toggling of the disordered nitrate anions. The temperature-dependent dielectric constant measurements on 1 showed a desolvation-assisted dielectric relaxation behaviour, indicating the involvement of solvate molecules in establishing the long-range polar order. A new discrete octahedral metal-ligand cage was prepared by employing a flexible tripodal phosphoramide ligand. The polarization in this assembly originates from the toggling of the nitrate anions and its long-range order assisted by solvate molecules of water. The ferroelectric measurements of the cage gave a well-defined rectangular P-E hysteresis loop with a remnant polarization value. [ABSTRACT FROM AUTHOR]

A sterically hindered aryl phosphonic acid ArP(O)(OH)2 (Ar = 2,4,6-isopropylphenyl) is synthesized and structurally characterized. ArP(O)(OH)2 forms an interesting hydrogen-bonded corrugated sheet-type supermolecular structure in the solid-state.

The recent developments in the synthesis of organosilanols are discussed. The preparative and structural aspects of various types of silanols along with the emerging applications of silanols are reviewed.

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 H3PO4, H2PO4−, HPO42− and PO43− species. These imido anions are typically generated using strong main group organometallic reagents such as nBuLi, Et2Zn, Me3Al and nBu2Mg, etc. As a result, their coordination chemistry has been restricted to reactions in anhydrous aprotic solvents for a few main group metal ions. This account presents our findings on using certain soft transition metal such Ag(I) and Pd (II) for isolating these imido‐P(V) anions as their corresponding self‐assembled clusters and cages. Using the various salts of Ag(I) ions in reaction with 2‐pyridyl (2Py) functionalized phosphonium salts and phosphoric triamides, we obtained the mono‐ and dianionic form of these imido ligands {[P(N2Py)2(NH2Py)2]−, [P(N2Py)2(NH2Py)]−, [PO(N2Py)(NH2Py)2]2−} and derived interesting examples of tri, penta, hepta and octanuclear Ag(I) clusters. Interestingly, by using the salts of Pd (II) ions, the elusive imido‐phosphate trianions of the type [(RN)3PO]3− (R=tBu, cHex, iPr) were generated in a facile one pot reaction as their corresponding tri‐ and hexanuclear clusters of the type {Pd3[(NR)3PO](OAc)3}n (n=1 or 2). These trianions acts as a cis‐coordinated hexadentate ligand for a trinuclear Pd (II) cluster and serve as the polyhedral building units for constructing hitherto unknown family of neutral cages in tetrahedral {Pd3[(NiPr)3PO]4(L)6} and cubic {Pd3[(NiPr)3PO]8(L)12} structures in the presence of suitable linker ligands (L2−). These cages show interesting host‐guest chemistry and post‐assembly reactions. Remarkably, by employing chiral tris(imido)phosphate trianions, enantiopure chiral cages of the type [(Pd3X*)4(L)6], ([X*]3−=RRR‐ or SSS‐[PO(N(*CH(CH3)Ph)3]3−), were synthesized and used for the chiral‐recognition and enantio‐separation of small racemic guest molecules. Some of these chiral cages were also shown to exhibit polyradical framework structures. In future, these and other similar types of cages are envisioned as potential molecular vessels for performing the reactions in their confined environment. The enantiomeric cages can be probed for asymmetric catalysis and the separation of a range of small chiral molecules. [ABSTRACT FROM AUTHOR]

The aromatic group substituents of the two silanediols influence the hydrogen bonding with diol molecules. The N-bonded silanediol forms two types of hexameric clusters in the solid state, whereas the other silanediol exist as cyclic hydrogen-bonded dimers, transforming into polymeric structure by further intermolecular hydrogen bonding.