Rubidium Cations Research Articles

MIL‐50, an Open‐Framework GaPO with a Periodic Pattern of Small Water Ponds and Dry Rubidium Atoms: A Combined XRD, NMR, and Computational Study.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Bis(calix[4]diquinone) receptors: cesium- and rubidium-selective redox-active ionophores.

A new class of redox-active ionophore comprised of two calix[4]diquinone moieties connected through either alkylene or pyridylene linkages has been developed. Spectroscopic and electrochemical investigations, X-ray crystal structure analyses, and molecular modeling studies show butylene- and propylene-linked members of this family of redox-active receptors exhibit remarkable selectivity preferences and substantial electrochemical recognition effects toward cesium and rubidium cations.

MIL-50, an open-framework GaPO with a periodic pattern of small water ponds and dry rubidium atoms: a combined XRD, NMR, and computational study.

A new fluorinated gallium phosphate, MIL-50, has been synthesized under mild hydrothermal conditions using 1,6-diaminohexane. The chemical formula of MIL-50 is Rb(2)Ga(9)(PO(4))(8)(HPO(4))(OH)F(6).2N(2)C(6)H(18).7H(2)O. The structure is a network of hexameric units of Ga(3)(PO(4))(3)F(2) and Ga(3)(PO(4))(2)(HPO(4))F(3) via corner sharing. It creates a three-dimensional open-framework delimiting 6- and 18-ring channels running along the c axis. The diprotonated 1,6-diaminohexane and water molecules are trapped within the 18-ring pores, whereas the rubidium cations reside in the 6-ring ones. A double quantum (31)P NMR experiment and partial charge calculations indicate that water molecules are present under the form of periodic small clusters, lowering the multiplicity of one phosphorus site, P3. Though water hops within the clusters, the motion leaves the water pattern periodic. Rubidium is so tightly embedded into the framework that water moving in the large 18-ring channels does not reach it, leaving it therefore dry. The crystal framework may be ascribed to the orthorhombic space group Cmc2(1) (n degrees 36), a = 32.1510(2), b = 17.2290(3), c = 10.2120(1) A. The periodic water pattern has a different symmetry than that of the framework. A method has been devised to superpose the two sublattices that coexist in the same unit cell in order to have full occupancy of each site and to perform Madelung summations. This original method is of general interest for most zeolitic materials exhibiting a different symmetry for the framework and the template sublattices.

Solid-state rubidium exchange of zeolite NH 4Y

NH 4Y has been ion exchanged by reaction with solid Rb 2CO 3 to form RbY. This process has been followed with X-ray powder diffraction, mass spectrometry and NMR. Both 1 H and 87 Rb MAS NMR are very sensitive to the hydration level of the zeolite and have been used to investigate the solid-state exchange process. 87 Rb NMR shows that exchange begins instantaneously on grinding the two solids together: decomposition of Rb 2CO 3 is observed, together with the migration of Rb + into the zeolite pores. X-ray diffraction indicates that the reaction proceeds to completion by 400 °C. The structure of the final RbY product has been refined with Rietveld analysis and rubidium cations have been located at the SI ′ SII and SIII ′ positions. Residual sodium cations from the incomplete exchange of the ammonium starting material have been located at the SI position; this result was confirmed by 23 Na MAS NMR. No evidence for Rb occupation of the SI positions was observed. Considerable disorder is observed in the cages of the zeolite during the ion-exchange process, but refinements of the structures, using the in situ data, indicate that Rb + cations have entered the sodalite cages by 200 °C.

X-ray structural, vibrational and calorimetric studies of a new rubidium pentahydrogen arsenate RbH 5(AsO 4) 2

Synthesis, crystal structure, Raman, IR and DSC characterization are given for a pentahydrogen arsenate of rubidium. X-ray investigations showed that the title compound (abbreviated RPA) crystallizes in an orthorhombic structure, space group Pbca and lattice parameters a=7.9403(8) Å, b=9.8218(6) Å, c=20.4244(6) Å, V=1592.9(2) Å 3, Z=8 and ρ cal=3.072 g cm −3. The structure was solved from 1568 independent reflections with R 1=0.047 and WR 2=0.067, refined with 106 parameters. The structure is different from RbH 5(PO 4) 2 (abbreviated RPP). It can be regarded as consisting of isolated AsO 4 tetrahedra connected by strong H-bonds [2.432(6)–2.638(6) Å] to an infinite network. The AsO 4 3− groups are located in layers parallel to the ab plane, and interleaved rubidium cations ensure cohesion between the sheets. The short hydrogen bond [2.432(6) Å] is probably not symmetric. The Raman and infrared spectra at room temperature were investigated in the frequency ranges 15–1000 and 250– 4000 cm −1, respectively. An assignment of all the bands is given. Differential scanning calorimetry showed that RPA crystals do not exhibit any phase transition in the range 100–575 K.

Co-cation Conduction in Solid Solutions (K1 – xRbx)4P2O7–M2P2O7(M = Ca, Sr, Cd, Ba): Transport Numbers and Partial Ionic Conductivities

Transport numbers for potassium and rubidium cations in solid electrolytes (K1 – xRb x )3.8M0.1P2O7(M = Ca, Cd, Ba) are measured, and the co-cation nature of the electrolytes" conduction is confirmed. The concentration dependences of transport numbers are used to draw a conclusion about the ratio between mobilities of potassium and rubidium cations. The presence of an extremum in the concentration dependence of the activation energy for the rubidium-cation constituent of conduction is confirmed by the NMR method. The obtained results are explained by assuming that the polyalkaline effect is largely due to an ordering of mobile alkali cations.

The synthesis and characterisation of JBW-type zeolites. Part B: Sodium/rubidium aluminogermanate, Na 2Rb[Al 3Ge 3O 12]·H 2O

An aluminogermanate possessing the zeolite JBW framework topology has been synthesized from a sodium- and rubidium-containing reagent mixture. The material, of composition Na 2RbAl 3Ge 3O 12·H 2O, has been structurally characterized via single crystal X-ray diffraction, and adopts space group Pmn2 1 with cell parameters a=15.6241(9), b=8.2586(6), and c=5.2442(6) Å. The material possesses a strictly alternating array of framework AlO 4 and GeO 4 tetrahedra, displaying no evidence of the superlattice observed for the aluminosilicate analogue. Sodium cations reside in the dehydrated six-rings, with rubidium cations and water molecules in the eight-rings. The structural parameters are compared with those derived for other materials possessing JBW topology.

Synthesis, Crystal Structure, and Properties of Polymeric Rb12Nb6Se35, a Novel Ternary Niobium Selenide Consisting of Infinite Anionic Chains Built Up by Nb2Se11Units Containing an Uncommon Se4−3-Fragment

Rb12Nb6Se35is the first ternary niobium polyselenide composed of infinite anionic chains. These are well separated by rubidium cations. It crystallizes in the orthorhombic space groupPbcnwith unit cell dimensionsa=8.5811(1) Å,b=13.7152(1) Å,c=56.5225(4) Å, andZ=4. The least-squares refinement againstF2with anisotropic displacement parameters for all atoms yieldsR1=5.78 and wR2=12.81. The anionic polymeric chains are arranged in layers parallel to the (010) plane, and successive planes are rotated by 35° against each other. Nb2Se11units composed of two face-sharing NbSe7pentagonal bipyramids are the building blocks of the structure. They are interconnected by Se2−2and Se2−3polyanions, giving rise to infinite1∞[Nb6Se35]12−chains. Within the Nb2Se11units an unusual nearly linear Se3fragment is found which must be formulated as Se4−3.

Cation analysis in electronics-grade organic solvents by ion chromatography

Many organic solvents are used in the manufacture of semiconductor products, especially as components of the photoresist or as rinse solvents. Assessing the concentration of trace alkali and alkaline earth metal contaminants in these materials is important in order to control circuit defects brought about by the presence of ionic contaminants deposited on the surface during the manufacturing process. This paper describes an ion chromatographic (IC) procedure for the analysis of alkali and alkaline earth metals in the water-immiscible organic solvents methyl n-amyl ketone (2-heptanone, MAK), n-butyl acetate (NBA), and propylene glycol monomethyl ether acetate (PM acetate, PMA). The procedure consists of in-vial aqueous extraction of the organic solvent followed by on-line preconcentration of the extracted cations onto a Dionex CG-12A guard column and subsequent analysis by ion chromatography. The IC analysis uses a Dionex CS-12A column with isocratic sulfuric acid eluent at elevated temperature and rubidium cation added as internal standard. Data obtained using this method compares well with data from inductively coupled plasma MS analysis of the same materials. Reporting limits for the method are at the one part-per-billion ( w/ w) level for all cations (Li, Na, K, Ca, Mg). The method is simple to implement, automatable, and relatively free from the possibility of contamination during the analysis.

Syntheses and Crystal Structures of Two New Hydrated Rubidium Zinc Phosphates: RbZn2(HPO4)2(H2PO4)·2H2O, a Layered Phase Containing Octahedral and Tetrahedral Zinc Centers, and RbZn(HPO4)(H2PO4)·H2O Containing One-Dimensional Chains of 4-Rings

The solution-mediated syntheses, single crystal structures, and physical properties (TGA, IR) of RbZn2(HPO4)2(H2PO4)·2H2O and RbZn(HPO4)(H2PO4)·H2O are reported. RbZn2(HPO4)2(H2PO4)·2H2O is a new noncentrosymmetric layered phase built up from ZnO6, ZnO4, and PO4polyhedra-sharing vertices as Zn–O–P and Zn–O–Zn bonds. Eleven-coordinate rubidium cations provide interlayer charge compensation for the anionic Zn/P/O/H sheets. RbZn(HPO4)(H2PO4)·H2O is isostructural with NH4Zn(HPO4)(H2PO4)·H2O and consists of infinite chains of tetrahedral 4-rings connected by Zn–O–P bonds. Crystal data for RbZn2(HPO4)2(H2PO4)·2H2O is:Mr=541.20, orthorhombic, space groupP2l2l2l(No. 19),a=7.6458(9),b=9.965(2),c=15.603(3) Å,V=1188.8(3) Å3,Z=4,R(F)=3.90%,Rw(F)=3.91%, (1695 observed reflections withI>3σ(I)). Crystal data for RbZn(HPO4)(H2PO4)·H2O isMr=361.83, triclinic, space groupP1(No. 2),a=7.712(2),b=7.9824(7),c=8.0422(9) Å,α=64.313(7)°,β=84.90(2)°,γ=72.364(9)°,V=424.6(2) Å3,Z=2,R(F)=3.97%,Rw(F)=4.24%, (1794 observed reflections withI>3σ(I)).

Mixed Valent Molybdenotungsten Monophosphate Rb2Mo2WO5(PO4)3: An Interconnected Tunnel Structure

A new mixed valent molybdenotungsten monophosphate Rb2Mo2WO5(PO4)3has been synthesized. It crystallizes in theP21/nspace group witha=10.756(2) Å,b=9.493(1) Å,c=15.478(3) Å,β=108.99(2)°. The structure of this phase consists of corner-sharing singleMO6octahedra,M2O11bioctahedral units, and monophosphate PO4groups forming large interconnected tunnels running along b and a where the rubidium cations are located. The complex host lattice [Mo2WP3O17]∞can be described by the assemblage of enantiomorphic [M3P3O20]∞chains running along a. A preferential occupation of two out of three octahedral sites by molybdenum is observed and a distribution of the hexavalent and pentavalent species in these different sites is proposed. The rather large Rb–O distances observed for the three kinds of rubidium sites suggest possible mobility of the Rb+cations in agreement with their high thermal factors.

Influence of Rubidium Cations on Hydrogen and Deuterium Electrosorption in Palladium.

A comparative cyclic voltammetric study of the hydrogen and deuterium sorptions into a thin layer palladium electrode has been performed in acidic and basic solutions containing rubidium cations. As in the case of other alkali cations, rubidium appears to clearly influence the {alpha}- to {beta}- phase transition only in basic solution.

Complexation of caesium and rubidium cations with crown ethers in N,N-dimethylformamide

The 133Cs NMR method was used to study the complexation of a series of crown ethers with caesium cations in NN-dimethylformamide (DM F). A competitive' 13Cs NMR technique was also used to probe the complexation of rubidium cations with the same crown ethers. The ligand 18-crown-6 forms the most stable complexes with caesium and rubidium cations. The effect of the addition of the substituent group(s) on the crown ring and the effect of the replacement of the oxygen donor atoms with nitrogen and sulfur atoms in 18-crown-6 were studied. The results show that the complex formation constants with Cs + cation increase through the series: dithia-18-crown-6 ⪡ diaza-18-crown-6 < dibenzo-18-crown-6 < dicyclohexano-l8-crown-6 < 18-crown-6. The trend with rubidium metal ion is: diaza-l8-crown-6 < dicyclohexano-l8-crown-6 < dibenzo-l8-crown-6 < 18-crown-6. Among the ligands studied, only 18-crown-6 and dicyclohexano-24-crown-8 form both 1 : 1 and 2 : 1 (ligand : cation) complexes with the caesium cation in DMF.

Supercritical Ammonia Synthesis and Characterization of Four New Alkali Metal Silver Antimony Sulfides:MAg2SbS4andM2AgSbS4(M= K, Rb)

Four new semiconducting quaternary antimony sulfides, KAg2SbS4(I), K2AgSbS4(II), RbAg2SbS4(III), and Rb2AgSbS4(IV) were prepared in supercritical ammonia at 160°C in 4 days from the appropriate mole ratios of K2S4, K2CO3, or Rb2CO3with Ag, Sb2S3, and S8. Both silver-rich materials, I and III, crystallize in structure types previously observed in BaAg2GeS4and SrCu2SnS4, respectively. However, it was determined that the space group of the latter compound was inaccurately reported in the literature. Novel structure types were obtained for II and IV. The structures of I–III contain three-dimensional anionic frameworks, either [Ag2SbS4]−or [AgSbS4]2−, built from a variety of edge- or vertex-shared antimony sulfide and silver sulfide tetrahedra. The alkali metal cations in I and II reside in two orthogonal, intersecting channels, and in three isolated one-dimensional channels in III. Compound IV has a layered structure, with a double layer of rubidium cations separating the neighboring anionic frameworks. It is noteworthy that I–III crystallize in noncentrosymmetric space groups. The structural diversity resulting from the condensation of quite regular SbS4and distorted AgS4tetrahedra in these four compounds and their optical band gaps are discussed. Crystal data: (I), red polyhedron, tetragonal space group,I42m,a= 6.886(1) Å,c= 8.438(2) Å,V= 400.16(9) Å3,Z= 2, andR(wR) = 0.0397(0.0335); (II), yellow plate, orthorhombic space group,Pnn2,a= 10.348(2) Å,b= 10.522(2) Å,c= 7.946(2) Å,V= 865.2(3) Å3,Z= 4, andR(wR) = 0.0377(0.0392); (III), yellow-orange needle, trigonal space group,P3221,a= 6.630(1) Å,c= 16.700(2) Å,V= 635.8(2) Å3,Z= 3, andR(wR) = 0.0244(0.0310); (IV), yellow polyhedron, monoclinic space group,P21/n,a= 8.229(3) Å,b= 10.857(2) Å,c= 10.346(2) Å, β = 91.55(2)°,V= 924.0(4) Å3,Z= 4, andR(wR) = 0.0377(0.0405).

Rb(2)[Ga(4)(HPO(4))(PO(4))(4)].0.5H(2)O: A New Gallium Phosphate Containing Four-, Five, and Six-Coordinated Gallium Atoms.

The synthesis and structure of a new gallium phosphate is described; the framework structure consists of four-, five-, and six-coordinated Ga atoms linked by phosphate groups to form eight -membered rings that house the rubidium cations and water molecules, and which are connected to give rise to infinite channels with eight-membered windows along [100].

Two New Noncentrosymmetric Rubidium Titanium Phosphate Phases: Rb2Ti3O2(PO4)2(HPO4)2 and Rb3Ti3O(P2O7)(PO4)3

Two new, noncentrosymmetric, rubidium titanium phosphate phases have been synthesized by hydrothermal and flux methods and structurally characterized by single crystal X-ray diffraction methods. Rb2Ti3O2(PO4)2(HPO4)2 (Rb2Ti3P4) consists of a three-dimensional framework of vertex-sharing TiO6, PO4, and HPO4 polyhedra interconnected via Ti-O-Ti and Ti-O-P bonds, surrounding large, one-dimensional channels occupied by eight-coordinate "guest" Rb+ cations: these channels propagate along the a-crystallographic direction. The framework includes [Ti3O16] units built up from three adjacent TiO6 octahedra sharing trans-O-Ti-O links, crosslinked by the (hydrogen)phosphate groups. Rb3Ti3O (P2O7)(PO4)3 (Rb3Ti3P5) is built up from a network of TiO6 and PO4 groups, linked via Ti-O-Ti, Ti-O-P, and P-O-P bonds, enclosing channels occupied by the guest rubidium cations. The structural motif of the framework includes isolated TiO6 and [Ti2O11] groups, interconnected by (pyro)phosphate groups. The Rb+ cations occupying the one-dimensional channels are eighffold coordinate by oxygen atoms. Rb3Ti3O(P2O7)(PO4)3 (2 linked octahedra) and RbaTi3O2(PO4)2(HPO4)2(3 linked octahedra) are considered in relation to the nonlinear optical materials KTiOPO4 (KTP) and RbTiOPO4 (RbTP) which contain infinite -O-Ti-O-Ti-O-chains. The typical short, "titanyl" Ti[]O bond found in KTP and RbTP is barely apparent in Rb2Ti3O2(PO4)2(HPO4)2 and Rb3 Ti3O(P2O7)(PO4)3, and the poor nonlinear response of the title compounds is discussed in relation to the extended Ti/O chain structure in RbTP. Crystal data: Rb2Ti3P4O18H2, Mr = 728.5, monoclinic, P21, a = 5.1851(4) Å, b = 16.770(2) Å, c = 8.4939(6) Å β = 90.940(3) °, V = 738.48 Å3, Z = 2. Final residuals of R = 4,24% and Rw = 4.40% were obtained for 2331 unique reflections with I > 3σ(I). Rb3Ti3P5O20, Mr = 874.96, orthorhombic, Pca21, a = 18.280(1) Å, b = 6.295(1) Å, c = 14.773(1) Å, V = 1700.0 Å3, Z = 4, R = 4.00%, and Rw = 3.70% for 1498 unique reflections with I > 3σ(I).

A general method for the determination of the kinetic stability of macrocyclic alkali-metal complexes with rates of decomplexation below 10–3s–1

A general method has been developed for the determination of kinetic stabilities of macrocyclic alkali-metal complexes with rates of decomplexation (Kd) below 10–3 s–1, by use of radioactive isotopes. This method offers the possibility to study the influence of the solvent polarity and of the salt concentration in solution on the rate of decomplexation of macrocyclic metal complexes. Further advantages are the small amounts of ligand required for these determinations and the simplicity of the method. Furthermore, it is possible by this method to study the degenerate exchange of sodium for sodium and of rubidium for rubidium. By this method the kinetic stabilities of the sodium and rubidium complexes of calixspherands 1–4 were determined. Calixspherand 3 forms kinetically very stable complexes with sodium and rubidium cations in acetone and Me2SO in the presence of high concentrations of sodium cations in solution; half-life times of exchange are 855 (Na+) and 528 (Rb+) h in acetone and 352 (Na+) and 845 (Rb+) h in Me2SO, respectively. The results of this method were verified by an independent 1H NMR spectroscopic method.

RbFe(HPO4)2: an iron(III) phosphate with an intersecting tunnel structure

A new iron(III) phosphate, RbFe(HPO4)2, has been synthesised hydrothermally at 230°C and characterized by single-crystal X-ray diffraction. The crystal is trigonal with a very long c axis: space group Rc, a= 8.160(1), c= 52.75(1)A, Z= 18 and R= 0.0207. The compound adopts an intersecting tunnel structure, with the rubidium cations in the tunnels. The framework consists of corner-sharing FeO6 octahedra and HPO4 groups. A triclinic polymorph was also obtained.

Fluorenylrubidium · N,N, N′, N″, N″-pentamethyldiethylenetriamine: A square-wave-like polymeric chain in the solid state

The transmetallation of fluorenyllithium with RbO tBu in THF yields fluorenylrubidium, which in the presence of PMDTA ( N,N, N′, N″, N″-pentamethyldiethylenetriamine) gives cube-shaped crystals of [C 13H 9Rb·PMDTA] n ( 1). An X-ray diffraction study has shown that 1 adopts a “square-wave-like” polymeric chain structure, in which each rubidium cation is coordinated to two fluorenyl anions and one triamine ligand.

The first crystal structure of a bis(crown ether) compound that forms an intramolecular sandwich complex with rubidium picrate

Abstract 3-Nitro-2,6-bis(4′-benzo-15-crown-5)aminopyridine and its rubidium picrate complex were synthesized, and the first known example of a bis(crown ether) rubidium picrate intramolecular sandwich complex was obtained. The structure is confirmed by solid state studies: C39H44N7O19Rb·CH3OH·H2O, triclinic, P1. a = 11.481(4), b = 14.519(4), c = 15.960(6) A, α = 63.28(3), β = 73.75(3), γ = 80.66(3)°, Dc = 1.53 g/cm3, Z = 2, and R = 0.091 for the 2350 observed reflections. The rubidium cation is intramolecularly sandwiched by ten oxygen atoms. The Rb[sbnd]O bond lengths range from 2.849(12) A to 3.02(2) A. The picrate anion is linked by ionic interactions to the large cation.