RESUMEN
A new inorganic-organic hybrid polyoxoboroniobate {H4K2[Cu(cis-en)2(H2O)]9[Cu(cis-en)2]6[Cd2(cis-en)2(trans-en)][LiB2Nb29O86]2·79H2O} (1, en = ethylenediamine), is built from pagoda-shaped {LiB2Nb29O86} clusters, linear {Cd2(cis-en)2(trans-en)} bridging units, and copper-amine complexes. The {LiB2Nb29O86} cluster represents the first example of combining oxoboron clusters with polyoxoniobate clusters (PONbs). It consists of an unusual HPONb fragment {LiNb18O54}, a fused-ring structural boroniobate cluster {B2Nb5O13}, and a classical Lindqvist {Nb6O19} fragment. The {Cd2(cis-en)2(trans-en)} and [Cu(cis-en)2]2+ complexes link the pagoda-shaped {LiB2Nb29O86} clusters into 1D infinite ladder chains. This is the first instance of simultaneous coordination of the cis-en and trans-en ligands with a single metal cation in the inorganic-organic hybrid PONb family. Furthermore, 1 exhibits good proton conductivity.
RESUMEN
In this research, indium ions were introduced into polyoxoniobates (PONbs) reaction systems to facilitate the construction of different {SiNb18O54}-based aggregates, including an {In(en)2{SiNb18O54}2} (en = ethylenediamine) dimer, an {[InO2][In2(en)O3]2{SiNb18O54}3} trimer, and an {[In(en)2][InO2][In7(en)5O9]{SiNb18O54}4} tetramer. Interestingly, these aggregates were further assembled into three uncommon extended PONb architectures in the presence of [Cu(en)2]2+ complexes, namely, H3[Cu(en)2(H2O)][Cu(en)2]6[Cu(en)2]2{[In(en)2][K2{SiNb18O54}(H2O)6]2}·1.5en·16H2O, H9{[Cu(en)2]6{[Cu(en)2]3[Cu(en)2(H2O)][In(H2O)2][In2(en)(H2O)2(OH)]2{SiNb18O54}3}·5en·29H2O, and H14[Cu(en)2]0.5[Cu(en)2(H2O)]{[Cu(en)2]2{[Cu(en)2]3[Cu(en)2(H2O)]5[K(H2O)2][In(H2O)2][In(en)2][In7(OH)9(en)5]{SiNb18O54}4}·7en·39H2O. In addition, all of them have good water vapor adsorption capacities and moderate proton transport capabilities. The above results indicate that introducing suitable heteroatoms to induce the aggregation PONb building blocks and further assembling them into new structures is an effective strategy to enrich the PONbs' structural diversity and develop new functional materials.
RESUMEN
Nature seems to favor the formation of closed anion-templated silver clusters. How precisely to create non-closed sliver clusters remains an interesting challenge. In this work, we propose that the use of transition-metal-coordination-cluster substituted polyoxometalates (TMCC-substituted POMs) as templates is an effective synthetic strategy for creating the non-closed silver clusters, as demonstrated by the obtainment of four types of rare non-closed silver cluster species of Ag38-TM (TM = Co, Ni or Zn), Ag37-Zn, {Ag37-Zn}∞ and Ag36-TM (TM = Co, Ni). The idea of the strategy is to employ the TMCC-substituted POMs containing cluster modules with different bond interactions with Ag+ ions as templates to guide the formation of the non-closed silver clusters. For example, TMCC-substituted POM clusters are used as templates in this work, which contain POM modules that can coordinate with the Ag+ ions and TMCC moieties that are difficult to coordinate with the Ag+ ions, leading to the Ag+ ions being unable to form closed clusters around TMCC-substituted POM templates. The work demonstrates a promising approach to developing intriguing and unexplored non-closed silver clusters.
RESUMEN
A rare all-inorganic high-nuclearity mixed-valent {Mn11} cluster embedded polyoxoniobate, K25H43{(Te4Nb9O33)3(Nb6O19)5(TeVINb5O14)[(TeIVO3)2(MnII7MnIII4O19)]}·97H2O (1), has been synthesized by a one-pot reaction. Compound 1 contains the largest manganese cluster {Mn11} core among polyoxoniobates reported to date. {Mn11} consists of three quasi-cubane {Mn3O4} units and is simultaneously encapsulated by lacunary α-Keggin {Te4Nb9O36} and Lindqvist {Nb6O19} units. Compound 1 exhibits significant magnetic anisotropy and excellent water solubility and stability. The findings suggest a new, all-inorganic polynulear Mn-based structural paradigm for aqueous solution chemistry and magnetic materials.
RESUMEN
An unusual crystalline porous framework constructed from four types of cages, including all-inorganic Keggin-type polyoxometalate (POM) cages [H3W12O40]5-, organic hexamethylenetetramine (Hmt) cages, nanosized silver-Hmt coordination cages, and giant POM-silver-Hmt cages, was hydrothermally synthesized and structurally characterized. The framework features a highly symmetrical structure with one-dimensional nanoscale channels and holds good thermal/solvent stability, which endow it with proton conduction properties and heterogeneous catalytic activity for pyrazole. This paper not only contributes to broadening the structural diversity of cage-based crystalline porous framework materials but also sheds new light on the design of new functional framework materials.
RESUMEN
Here, a case of bilayer heterojunction Pd-containing polyoxotungstate (POW), connecting a Te3Pd3 ring and an Anderson-like TeW6 cluster, has been synthesized. The Anderson-like cluster is the first example in POW. The coordination of Pd in the ring with the S atom on the sulfo group breaks the traditional coordination configuration of Pd and O in polyoxometalates (POMs), enriching the structural types of Pd-containing POMs. In addition, the hybrid bilayer heterojunction structure at the molecular level not only provides high thermal stability but also results in spatial arrangement anisotropy, leading to up to five times the anisotropic proton conductivity.
RESUMEN
Four different structural compositions of organophosphate, 3d transition metal, 4f lanthanide and polyoxoniobate (PONb) are unified in a system for the first time to form a new type of organophosphate 3d-4f heterometallic inorganic-organic hybrid PONb nanowire. Interesting magnetic anisotropy and slow magnetic relaxation are found in the PONb nanowire.
RESUMEN
Atomically precise low-nuclearity (n<10) silver nanoclusters (AgNCs) have garnered significant interest due to their size-dependent optical properties and diverse applications. However, their synthesis has remained challenging, primarily due to their inherent instability. The present study introduces a new feasible approach for clustering silver ions utilizing highly negative and redox-inert polyoxoniobates (PONbs) as all-inorganic ligands. This strategy not only enables the creation of novel Ag-PONb composite nanoclusters but also facilitates the synthesis of stable low-nuclearity AgNCs. Using this method, we have successfully synthesized a small octanuclear rhombic [Ag8]6+ AgNC stabilized by six highly negative [LiNb27O75]14- polyoxoanions. This marks the first PONb-protected superatomic AgNC, designated as {Ag8@(LiNb27O75)6} (Ag8@Nb162), with an aesthetically spherical core-shell structure. The crystalline Ag8@Nb162 is stable under ambient conditions, What's more, it is water-soluble and able to maintain its molecular cluster structure intact in water. Further, the stable small [Ag8]6+ AgNC has interesting temperature- and pH-dependent reversible fluorescence response, based on which a multiple optical encryption mode for anti-counterfeit technology was demonstrated. This work offers a promising avenue for the synthesis of fascinating and stable PONb-protected AgNCs and sheds light on the development of new-type optical functional materials.
RESUMEN
In this work, a novel organodiphosphate-containing inorganic-organic hybrid polyoxoniobate (PONb) ring {(PO3CH2CH2PO3H)4Nb8O16}4- (Nb8P8) has been achieved by a one-pot hydrothermal method. The ring is constructed from a tetragonal {Nb8O36} motif and four {PO3CH2CH2PO3H} ligands. Interestingly, Nb8P8 can be joined together via K-H2O clusters {K2(H2O)4(OH)2} to form one-dimensional chains {[K2(H2O)4(OH)2]Nb8P8}n and further linked by {Cu(en)2}2+ (en = ethylenediamine) complexes, resulting in a three-dimensional supramolecular framework {[Cu(en)2]2[K2(H2O)4(OH)2]Nb8P8}·3en·H2O (1). 1 exhibits good chemical and thermal stability and has a high water vapor adsorption capacity of ≤224 cm3 g-1 (22.71 mol·mol-1) at 298 K, outperforming most of the known polyoxometalate-based materials. Impedance measurements prove that 1 can transfer protons with moderate conductivity. This study not only contributes to the structural diversity of organodiphosphate-containing PONbs and PONb rings but also provides a reference for the development of PONb-based materials with unique performance.
RESUMEN
A 3D tellurium-substituted heteropolyoxoniobate framework H5K3Na[Cu(en)2]2[Cu(en)0.75(H2O)2.5]{[(Te2Nb19O58)(µ3-OH)2]}·24H2O (1, en = ethylenediamine) with a 6-connected pcu topology is built from heart-shaped {Te2Nb19O60} clusters and copper complexes. The {Te2Nb19O60} cluster represents the new tellurniobate structure type with a 19-nuclearity Nb cluster. It consists of two new monovacant Lindqvist {Nb5O19} clusters, one boat-shaped {Nb9O32} cluster and two TeO32- anions. The {Te2Nb19O60} polyanions are interlinked by [Cu(en)2]2+ complexes into a 2D (4, 4) grid-like layer containing rhombic sheets. The Cu2+ supports the adjacent layers through Te-O-Cu-O-Te- bonds to form a three-dimensional heteropolyoxoniobate framework with 1D channels. This compound exhibits good chemical and solvent stability and proton conductivity, with a conductivity of 7.9 × 10-3 S cm-1 at 85 °C under 98% RH.
