Self-Assembly of Ag⁺/[PW₁₁NbO₄₀]^4– Complexes in Nonaqueous Solutions

Abstract

Self-assembly between Ag+ and [PW11NbO40]4– in N- and O-donor solvents (nitriles and amides) has been studied. In the case of dimethylformamide (DMF), formation of a yellow [Ag4(DMF)12]­[PW11NbO40] (1a) metastable phase and a colorless [Ag4(DMF)10]­[PW11NbO40] (1) stable phase was observed. In acetonitrile (CH3CN), the product was [Ag­(CH3CN)4]2{[Ag­(CH3­CN)3]2­[PW11­NbO40]} (2a). By contrast, [SiW12O40]4– of the same size and charge as [PW11NbO40]4– produces [Ag­(CH3CN)3]4[SiW12O40] (3a). Partial desolvation of 2a and 3a leads to Ag4[PW11NbO40]·7.5CH3CN (2) and Ag4[SiW12O40]·7.5CH3CN (3), respectively. The CH3CN molecules in the structure of 2 are labile, and this compound was used as the starting material to study solvent-exchange processes in N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMA), diethylformamide (DEF), and benzonitrile (PhCN) solutions. These solvent reactions yield [Ag­(DMA)4]­[Ag3(DMA)6]­[PW11NbO40] (4), [Ag2­(NMP)4­(CH3CN)]2­[PW11­NbO40]·1.3NMP (5a), [Ag2­(NMP)5]2­[PW11­NbO40] (5b), Ag4­[PW11­NbO40]·9.5DEF (6), and [Ag­(PhCN)4]2­[{Ag­(PhCN)3}2­PW11­NbO40] (7). All products were isolated and characterized by single-crystal X-ray diffraction (except for 2 and 3), IR, elemental analysis, and thermogravimetric analysis techniques. The O-donor solvents favor polynuclear, solvent-bridged cationic aggregates. In the case of DMF, DMA, and DEF discrete, tri- and tetranuclear polycations are observed, while in the case of NMP, the formation of infinite polycationic structures takes place. By contrast, the N-donor solvents (CH3CN and PhCN) favor mononuclear cations, which can exist either as distorted tetrahedral, isolated [Ag­(Solv)4]+ cations or as pseudotriangular {Ag­(Solv)3}+ units, additionally coordinated to a polyoxometalate. Screening of the luminescent properties for solid samples of 1–7 revealed that only 5a/5b and 7 are emissive. In particular, the sample containing 5a and 5b demonstrates long-lived phosphorescence with a 30 ms lifetime.

Synthesis and Thermochromic Luminescence of Ag(I) Complexes Based on 4,6-Bis(diphenylphosphino)-Pyrimidine

“…Herein, we report on the synthesis and investigation of two Ag(I) compounds derived from 4,6-bis(diphenylphosphino)pyrimidine and AgNO 3 or AgBF 4 . Both compounds manifest pronounced thermochromic luminescence, which appears as a reversible changing of the emission color from yellow at 300 K to orange/red at 77 K. It should be noted in this regard that the Ag(I) complexes endowed with such property are very limited in number [13,[46][47][48][49].…”

“…1 H, 13 C, and 31 P{ 1 H} NMR spectra were recorded using a Bruker AV-500 spectrometer at 500. S5 and S6) were measured on the same instrument.…”

“…Recently, Ag(I)-based metal-organic compounds have attracted increased attention as promising antibacterial agents [1,2], luminescent sensorics [3,4], and potential emitters for lighting application [5][6][7]. The rich coordination abilities of Ag(I) ion coupled with easy accessibility of the organic ligands provide ample opportunities for the design of most diverse coordination architectures covering both simple molecules and sophisticated metal-organic frameworks [8][9][10][11][12][13]. The charge balancing anions (NO 3 − , OAc − , OTf − , ClO 4 − , BF 4 − , PF 6 − , halides, etc.)…”

Synthesis of Two New Ni12‐Cluster Substituted Sandwiched Phosphotungstates Organic‐Cluster and their Magnetic Property

“…Transition‐metal‐substituted polyoxometalates (TMSPs) as a part of POMs with excellent performance have become an indispensable part of POMs [15–18] . A series of TMPS with function had been explored, Ag + /[PW 11 NbO 40 ] 4− complexes with luminescent properties was self‐assembled, [19] nickel‐containing POMs was applied as water oxidation catalyst [20] . TMSPs as a class of well‐insulated clusters of controlled nuclearity and topology had been investigated their exchange interactions in magnetic transition‐metal (TM) clusters.…”

Assembly of 12-Tungstovanadate-Templated Nanocage and Nanocomposites with Single-Walled Carbon Nanotubes as Anodes in Lithium-Ion Batteries

“…It is not hard to see that some angular orientations (60–78°) for building space polygons are not explored to date. In contrast, polyoxometalates (POMs) as universal building blocks have been widely used to construct hybrid compounds, − owing to unique properties, and recently exhibited great potential application in energy storage, due to the reversible multielectron redox. − Furthermore, to surmount the good solubility of POMs in electrolyte, POMs as template were often introduced into metal–organic frameworks then applied in LIBs. − However, exploration of POMs-templated MOCs for LIBs remain extremely rare, limited to the sole example of Zn-POMCF, to the best of our knowledge.…”