Atmospheric chemistry of n-C(x)F(2)(x)(+1)CHO (x = 1, 2, 3, 4): fate of n-C(x)F(2)(x)(+1)C(O) radicals

Smog chamber/FTIR techniques were used to study the atmospheric fate of n-C(x)F(2)(x)(+1)C(O) (x = 1, 2, 3, 4) radicals in 700 Torr O(2)/N(2) diluent at 298 +/- 3 K. A competition is observed between reaction with O(2) to form n-C(x)()F(2)(x)()(+1)C(O)O(2) radicals and decomposition to form n-C(x)F(2)(x)(+1) radicals and CO. In 700 Torr O(2)/N(2) diluent at 298 +/- 3 K, the rate constant ratio, k(n-C(x)F(2)(x)(+1)C(O) + O(2) --> n-C(x)F(2)(x)(+1)C(O)O(2))/k(n-C(x)F(2)(x)(+1)C(O) --> n-C(x)F(2)(x)(+1) + CO) = (1.30 +/- 0.05) x 10(-17), (1.90 +/- 0.17) x 10(-19), (5.04 +/- 0.40) x 10(-20), and (2.67 +/- 0.42) x 10(-20) cm(3) molecule(-1) for x = 1, 2, 3, 4, respectively. In one atmosphere of air at 298 K, reaction with O(2) accounts for 99%, 50%, 21%, and 12% of the loss of n-C(x)F(2)(x)(+1)C(O) radicals for x = 1, 2, 3, 4, respectively. Results are discussed with respect to the atmospheric chemistry of n-C(x)F(2)(x)(+1)C(O) radicals and their possible role in contributing to the formation of perfluorocarboxylic acids in the environment.     

Structure of an I- x (H2O)6 anion cluster in a 3D anion crystal host [I x (H2O)6Fe(CN)6 x H2O]4-

A planar structure of an anion cluster I- x (H2O)6 in a 3D supramolecular complex [Ru(bpy)3]2[I x (H2O)6Fe(CN)6 x H2O] has been determined by single-crystal X-ray analysis. In the supramolecule, the anion cluster I- x (H2O)6, together with the anion [Fe(CN)6 x H2O]2-, acts as a 3D crystal host, and the [Ru(bpy)3]2+ cations, as the guest molecules, occupy the vacancies of the 3D host framework. This is the first crystal example of the anion cluster I- x (H2O)6.     

Ab initio investigation of the electronic structure and bonding of the HC(N2)x(+) and HC(CO)x(+) cations, x = 1, 2

Employing the coupled-cluster approach and correlation consistent basis sets of triple and quadruple cardinality, we have investigated the electronic structure and bonding of the HC(N2)x(+) and HC(CO)x(+), x = 1, 2, molecular cations. We report geometries, binding energies and potential energy profiles. The ground states of HC(N2)+, HC(CO)+ and HC(N2)2(+), HC(CO)2(+) are of 3sigma- and 1A1 symmetries, respectively. All four charged species are well bound with binding energies ranging from 81 [HC(N2)+ (X3sigma-) --> CH+(a3pi) + N2(X1sigma(g)+)] to 178 [HC(CO)2(+)(X1A1) --> CH+(X1sigma+) + 2CO(X1sigma+)] kcal/mol. It is our belief that the X1A1 states of HC(N2)2(+) and HC(CO)2(+) are isolable in the solid state if combined with appropriate counteranions.     

Synthesis, characterization, and structures of Mn(DMHP)3 x 12H2O and Mn(DMHP)2Cl x 0.5H2O

This report describes the synthesis, characterization, and X-ray crystal structures of two Mn(III) complexes, Mn(DMHP)3 x 12H2O and Mn(DMHP)2Cl x 0.5H2O (DMHP = 1,2-dimethyl-3-hydroxy-4-pyridinone). Mn(DMHP)2Cl was prepared from the reaction of Mn(II) chloride with 2 equiv of DMHP under reflux in the presence of triethylamine. Mn(DMHP)3 was obtained by reacting Mn(II) acetate with 3 equiv of DMHP in the presence of sodium acetate. Mn(DMHP)3 could also be prepared by reacting Mn(OAc)3 x 2H2O with 3 equiv of DMHP in the presence of triethylamine. Both Mn(III) complexes have been characterized by elemental analysis, infrared spectroscopy, electronic paramagnetic resonance, electrospray ionization spectroscopy, electrochemical method, and X-ray crystallography. The X-ray crystal structure of Mn(DMHP)2Cl x 0.5H2O revealed a rare example of five-coordinated Mn(III) complexes with two bidentate ligands and a square pyramidal coordination geometry. Surprisingly, the average Mn-O (hydroxy) bond distance in Mn(DMHP)2Cl x 0.5H2O is approximately 0.025 A longer than that of the average Mn-O (carbonyl) bond, suggesting an extensive delocalization of electrons in the two pyridinone rings. The structure of Mn(DMHP)3 x 12H2O, a rare example of six-coordinate high-spin Mn(III) complexes without Jahn-Teller distortion, is isostructural to M(DMHP)3 x 12H2O (M = Al, Ga, Fe, and In). The electrochemical data for Mn(DMHP)3 suggests that the Mn(III) oxidation state is highly stabilized by three DMHP ligands. DMHP has the potential as a chelator for the removal of excess intracellular Mn and the treatment of chronic Mn toxicity.     

Tropochemical cell-twinning in the new quaternary bismuth selenides KxSn(6-2x)Bi(2+x)Se9 and KSn5Bi5Se13

The quaternary K(x)Sn(6-2x)Bi(2+x)Se(9) and KSn(5)Bi(5)Se(13) were discovered from reactions involving K(2)Se, Bi(2)Se(3), Sn, and Se. The single crystal structures reveal that K(x)Sn(6-2x)Bi(2+x)Se(9) is isostructural to the mineral heyrovskyite, Pb(6)Bi(2)S(9), crystallizing in the space group Cmcm with a = 4.2096(4) A, b = 14.006(1) A, and c = 32.451(3) A while KSn(5)Bi(5)Se(13) adopts a novel monoclinic structure type (C2/m, a = 13.879(4) A, b = 4.205(1) A, c = 23.363(6) A, beta = 99.012(4) degrees ). These compounds formally belong to the lillianite homologous series xPbS.Bi(2)S(3), whose characteristic is derivation of the structure by tropochemical cell-twinning on the (311) plane of the NaCl-type lattice with a mirror as twin operation. The structures of K(x)Sn(6-2x)Bi(2+x)Se(9) and KSn(5)Bi(5)Se(13) differ in the width of the NaCl-type slabs that form the three-dimensional arrangement. While cell-twinning of 7 octahedra wide slabs results in the heyrovskyite structure, 4 and 5 octahedra wide slabs alternate in the structure of KSn(5)Bi(5)Se(13). In both structures, the Bi and Sn atoms are extensively disordered over the metal sites. Some physicochemical properties of K(x)Sn(6-2x)Bi(2+x)Se(9) and KSn(5)Bi(5)Se(13) are reported.     

Tuning intermolecular magnetic exchange interactions in the solids C(x)F(2)(x)(CNSSS)(2)(AsF(6))(2): structural, EPR, and magnetic characterization of dimeric (x = 2, 4) diradicals

A series of diradical containing salts CxF2x(CNSSS)2(**2+0(AsF6-)2 {x = 2, 1[AsF6]2; x = 3, 3[AsF6]2; x = 4, 2[AsF6]2} have been prepared. 1[AsF6]2 and 2[AsF6]2 were fully characterized by X-ray, variable-temperature magnetic susceptibility, and solid-state EPR measurements, further allowing us to extend the number of examples of the family of rare 7pi RCNSSS(*+) radical cations. 1[AsF6]2: a = 6.5314(7) A, b = 7.5658(9) A, c = 9.6048(11) A, alpha = 100.962(2) degrees , beta = 96.885(2) degrees , gamma = 107.436(2) degrees , triclinic, space group P, Z = 1, T = 173 K. 2[AsF6]2: a = 10.6398(16) A, b = 7.9680(11) A, c = 12.7468(19) A, beta = 99.758(2) degrees , monoclinic, space group P21/c, Z = 2, T = 173 K. In the solid-state, CxF2x(CNSSS)2(**2+) (x = 2, 4) formed one-dimensional polymeric chains of dications containing discrete centrosymmetric radical pairs in which radicals were linked by four centered two-electron pi*-pi* bonds [12+, d(S...S) = 3.455(1) A; 22+, d(S...S) = 3.306(2) A]. The exchange interactions in these bonds were determined to be -500 +/- 30 and -900 +/- 90 cm-1, by variable temperature magnetic susceptibility measurements, respectively, providing rare experimental data on the singlet-triplet gaps in the field of thiazyl radicals. For 2[AsF6]2, the thermally excited triplet state was unambiguously characterized by EPR techniques [/D/ = 0.0254(8) cm(-1), /E/ = 0.0013(8) cm(-1)]. These experimental data implied a weakly associated nature of the radical moieties contained in the solids 1[AsF6]2 and 2[AsF6]2. Computational analysis of the dimerization process is presented, and we show that the 2c 4 electron pi*-pi* bonds in 1[AsF6]2 and 2[AsF6]2 have ca. 50% and 40% diradical character, respectively. In contrast, 3[AsF6]2.SO2, containing diradical C3F6(CNSSS)2(**2+) with an odd number of CF2 spacers, showed magnetic behavior that was consistent with the presence of monomeric radical centers in the solid state.     

Electronic properties of adsorbates on GaAs(001)-c(2x8)/(2x4)

A systematic experimental and theoretical study was performed to determine the causes of oxide-induced Fermi level pinning and unpinning on GaAs(001)-c(2 x 8)/(2 x 4). Scanning tunneling spectroscopy (STS) and density functional theory (DFT) were used to study four different adsorbates' (O(2), In(2)O, Ga(2)O, and SiO) bonding to the GaAs(001)-c(2 x 8)/(2 x 4) surface. The STS results revealed that out of the four adsorbates studied, only one left the Fermi level unpinned, Ga(2)O. DFT calculations were used to elucidate the causes of the Fermi level pinning. Two distinct pinning mechanisms were identified: direct (adsorbate induced states in the band gap region) and indirect pinnings (generation of undimerized As atoms). For O(2) dissociative chemisorption onto GaAs(001)-c(2 x 8)/(2 x 4), the Fermi level pinning was only indirect, while direct Fermi level pinning was observed when In(2)O was deposited on GaAs(001)-c(2 x 8)/(2 x 4). In the case of SiO on GaAs(001)-c(2 x 8)/(2 x 4), the Fermi level pinning was a combination of the two mechanisms.     

Atmospheric chemistry of perfluoroaldehydes (CxF2x+1CHO) and fluorotelomer aldehydes (CxF2x+1CH2CHO): quantification of the important role of photolysis

The UV absorption spectra of CF(3)CHO, C(2)F(5)CHO, C(3)F(7)CHO, C(4)F(9)CHO, CF(3)CH(2)CHO, and C(6)F(13)CH(2)CHO were recorded over the range 225-400 nm at 249-297 K. C(x)F(2)(x)(+1)CHO and C(x)F(2)(x)(+1)CH(2)CHO have broad absorption features centered at 300-310 and 290-300 nm, respectively. The strength of the absorption increases with the size of the C(x)F(2)(x)(+1) group. There was no discernible (<5%) effect of temperature on the UV spectra. Quantum yields for photolysis at 254 and 308 nm were measured. Quantum yields at 254 nm were 0.79 +/- 0.09 (CF(3)CHO), 0.81 +/- 0.09 (C(2)F(5)CHO), 0.63 +/- 0.09 (C(3)F(7)CHO), 0.60 +/- 0.09 (C(4)F(9)CHO), 0.74 +/- 0.08 (CF(3)CH(2)CHO), and 0.55 +/- 0.09 (C(6)F(13)CH(2)CHO). Quantum yields at 308 nm were 0.17 +/- 0.03 (CF(3)CHO), 0.08 +/- 0.02 (C(4)F(9)CHO), and 0.04 +/- 0.01 (CF(3)CH(2)CHO). The quantum yields decrease with increasing size of the C(x)F(2)(x)(+1) group and with increasing wavelength of the photolysis light. The photolysis quantum yield at 308 nm for CF(3)CHO measured here is a factor of at least 8 greater than that reported previously. Photolysis is probably the dominant atmospheric fate of C(x)F(2)(x)(+1)CHO (x = 1-4) and is an important fate of C(x)F(2)(x)(+1)CH(2)CHO (x = 1 and 6). These results have important ramifications concerning the yield of perfluorocarboxylic acids in the atmospheric oxidation of fluorotelomer alcohols.     

High temperature metalation of functionalized aromatics and heteroaromatics using (tmp)2Zn x 2 MgCl2 x 2 LiCl and microwave irradiation

A wide range of polyfunctional aryl and heteroaryl zinc reagents were efficiently prepared in THF via direct zincation using (tmp)2Zn x 2 MgCl2 x 2 LiCl and microwave irradiation. Ester and cyano functions as well as ketones are compatible with the high temperatures of the zincation. The resulting bis-organo zinc species undergo a number of subsequent reactions leading to highly functionalized aromatics and heteroaromatics in good to excellent yields.     

Synthesis and characterization of two novel mixed metal tellurates: KGaTeO5 x H2O and K3GaTe2O8(OH)2 x H2O

Single crystals of KGaTeO5 x H2O and K3GaTe2O8(OH)2 x H2O have been synthesized by supercritical hydrothermal techniques using Te(OH)6, Ga2O3 and KOH as reagents, and characterized by single crystal X-ray diffraction, thermal analysis, IR and Raman spectroscopy. Ion-exchange studies revealed KGaTeO5 x H2O, with its open-framework structure, is capable of exchanging both smaller (Na+) and larger (Rb+) ions. In addition, higher thermal stability and reversible hydration properties were observed for KGaTeO5 x H2O.     

A three-dimensional, noninterpenetrating metal--organic framework with the moganite topology: a simple (4(2)x6(2)x8(2))(4x6(4)x8)(2) net containing two kinds of topologically nonequivalent points

Self assembly of Cu(2+) with the multifunctional ligand 2-(4-pyridyl)thiazole-4-carboxylic acid (Pytac) affords the neutral 3D coordination polymer [Cu(3)(Pytac)(6)](H(2)O)(14) (hereafter, SZL-1), which has the rare moganite topology. The mineral moganite has a topology that is closely related to the well-known quartz topology, but the two topologies are differentiated by the number of topologically inequivalent nodes. Whereas only one kind of node is present in quartz, two types of topologically inequivalent nodes are present in moganite. The title compound, which has three vertices in its repeat unit, has two types of topologically inequivalent nodes with the overall vertex symbol (4(2)x6(2)x8(2))(4x6(4)x8)(2) corresponding to the moganite net. Prior to this report, few metal-organic framework materials (MOFs) have been found to contain more than one type of node, and SZL-1 is the first MOF with the moganite topology.     

An ionicity diagram for the family of [{Ru2(CF3CO2)4}2(TCNQR(x))] (TCNQR(x) = R-substituted 7,7,8,8-tetracyano-p-quinodimethane)

A diagram of energies between the HOMO of donor (D) and LUMO of acceptor (A) vs.ΔE(1/2)(DA) (= E(1/2)(D) - E(1/2)(A): E(1/2) = first-redox potential) clearly demonstrates the ionicity in the series of D/A assemblies, [{Ru(2)(CF(3)CO(2))(4)}(2)(TCNQR(x))]·n(solv) (TCNQR(x) = 2,5- or 2,3,5,6-R-substituted 7,7,8,8-tetracyano-p-quinodimethane; R(x) = H(4), F(2), Cl(2), Br(2), F(4), Me(2), (OMe)(2)).     

Novel luminescent metal-organic frameworks [Eu2L3(DMSO)2(MeOH)2] x 2 DMSO x 3 H2O and [Zn2L2(DMSO)2] x 1.6 H2O (L = 4,4'-ethyne-1,2-diyldibenzoate)

Novel metal-organic frameworks [Eu2L3(DMSO)2(MeOH)2] x 2 DMSO x 3 H2O, 1, and [Zn2L2(DMSO)2] x 1.6 H2O, 2, (L = 4,4'-ethyne-1,2-diyldibenzoate) have been synthesized and structurally characterized. Compound 1 is a 3D open framework while 2 features interpenetrating 2D sheets in the crystal lattice. Both compounds have been characterized with X-ray crystallography, elemental analysis, and thermogravimetric analysis. Compounds 1 and 2 are red and blue-green luminescent, respectively, in the solid state at ambient temperature. Thermogravimetric analysis implies that the extensive interpenetration stabilizes the lattice of 2, although it diminishes the porosity at the same time. The luminescence of 1 can be reversibly quenched and restored by the addition and removal of iodine.     

The role of water in synthesised hydrotalcites of formula Mg(x)Zn(6 - x)Cr2(OH)16(CO3) x 4H2O and Ni(x)Co(6 - x)Cr2(OH)16(CO3) x 4H2O--an infrared spectroscopic study

Infrared spectroscopy has been used to characterise synthesised hydrotalcites of formula Mg(x)Zn(6 - x)Cr2(OH)16(CO3) x 4H2O and Ni(x)Co(6 - x)Cr2(OH)16(CO3) x 4H2O. The infrared spectra are conveniently subdivided into spectral features based (a) upon the carbonate anion (b) the hydroxyl units (c) water units. Three carbonate antisymmetric stretching vibrations are observed at around 1358, 1387 and 1482 cm(-1). The 1482 cm(-1) band is attributed to the CO stretching band of carbonate hydrogen bonded to water. Variation of the intensity ratio of the 1358 and 1387 cm(-1) modes is linear and cation dependent. By using the water bending band profile at 1630 cm(-1) four types of water are identified (a) water hydrogen bonded to the interlayer carbonate ion (b) water hydrogen bonded to the hydrotalcite hydroxyl surface (c) coordinated water and (d) interlamellar water. It is proposed that the water is highly structured in the hydrotalcite interlayer as it is hydrogen bonded to both the carbonate anion, adjacent water molecules and the hydroxyl surface.     

Cyclometalated [Os(C-N)x(N-N)(3-x)]m+ mimetics of tris(2,2'-bipyridine)osmium(II): covering a 2 V potential range by known (x = 0, 1) and new (x = 2, 3) species (C-N = o-2-phenylpyridinato)

Electrochemical studies of [Os(C-N)(x)(N-N)(3-x)](m+) (1) consisting of known Os(II) species with x = 0 (a) and 1 (b) and crystallographically characterized new Os(III) bis- and tris-metalacycles with x = 2 (c) and 3 (d) (N-N = 2,2'-bipyridine, (-)C-N = 2-phenylpyridinato) revealed a Nernstian behavior in MeCN. A stepwise replacement of neutral N-N ligands by three anionic C-N donors covers a 2 V potential range from -1 to +1 V vs. Ag/AgCl for the Os(III)/Os(II) feature.     

Experimental investigation of the complete inner shell hydration energies of Ca2+: threshold collision-induced dissociation of Ca(2+)(H2O)x Complexes (x = 2-8)

The sequential bond energies of Ca(2+)(H(2)O)(x) complexes, where x = 1-8, are measured by threshold collision-induced dissociation (TCID) in a guided ion beam tandem mass spectrometer. From an electrospray ionization source that produces an initial distribution of Ca(2+)(H(2)O)(x) complexes where x = 6-8, complexes down to x = 2 are formed using an in-source fragmentation technique. Ca(2+)(H(2)O) cannot be formed in this source because charge separation into CaOH(+) and H(3)O(+) is a lower energy pathway than simple water loss from Ca(2+)(H(2)O)(2). The kinetic energy dependent cross sections for dissociation of Ca(2+)(H(2)O)(x) complexes, where x = 2-9, are examined over a wide energy range to monitor all dissociation products and are modeled to obtain 0 and 298 K binding energies. Analysis of both primary and secondary water molecule losses from each sized complex provides thermochemistry for the sequential hydration energies of Ca(2+) for x = 1-8 and the first experimental values for x = 1-4. Additionally, the thermodynamic onsets leading to the charge separation products from Ca(2+)(H(2)O)(2) and Ca(2+)(H(2)O)(3) are determined for the first time. Our experimental results for x = 1-6 agree well with previously calculated binding enthalpies as well as quantum chemical calculations performed here. Agreement for x = 1 is improved when the basis set on calcium includes core correlation.     

Stabilization and study of SrFe(1-x)Mn(x)O2 oxides with infinite-layer structure

A series of layered oxides of nominal composition SrFe(1-x)Mn(x)O(2) (x = 0, 0.1, 0.2, 0.3) have been prepared by the reduction of three-dimensional perovskites SrFe(1-x)Mn(x)O(3-δ) with CaH(2) under mild temperature conditions of 583 K for 2 days. The samples with x = 0, 0.1, and 0.2 exhibit an infinite-layer crystal structure where all of the apical O atoms have been selectively removed upon reduction. A selected sample (x = 0.2) has been studied by neutron powder diffraction (NPD) and X-ray absorption spectroscopy. Both techniques indicate that Fe and Mn adopt a divalent oxidation state, although Fe(2+) ions are under tensile stress whereas Mn(2+) ions undergo compressive stress in the structure. The unit-cell parameters progressively evolve from a = 3.9932(4) ? and c = 3.4790(4) ? for x = 0 to a = 4.00861(15) ? and c = 3.46769(16) ? for x = 0.2; the cell volume presents an expansion across the series from V = 55.47(1) to 55.722(4) ?(3) for x = 0 and 0.2, respectively, because of the larger effective ionic radius of Mn(2+) versus Fe(2+) in four-fold coordination. Attempts to prepare Mn-rich compositions beyond x = 0.2 were unsuccessful. For SrFe(0.8)Mn(0.2)O(2), the magnetic properties indicate a strong magnetic coupling between Fe(2+) and Mn(2+) magnetic moments, with an antiferromagnetic temperature T(N) above room temperature, between 453 and 523 K, according to temperature-dependent NPD data. The NPD data include Bragg reflections of magnetic origin, accounted for with a propagation vector k = ((1)/(2), (1)/(2), (1)/(2)). A G-type antiferromagnetic structure was modeled with magnetic moments at the Fe/Mn position. The refined ordered magnetic moment at this position is 1.71(3) μ(B)/f.u. at 295 K. This is an extraordinary example where Mn(2+) and Fe(2+) ions are stabilized in a square-planar oxygen coordination within an infinite-layer structure. The layered SrFe(1-x)Mn(x)O(2) oxides are kinetically stable at room temperature, but in air at ~170 °C, they reoxidize and form the perovskites SrFe(1-x)Mn(x)O(3-δ). A cubic phase is obtained upon reoxidation of the layered compound, whereas the starting precursor SrFeO(2.875) (Sr(8)Fe(8)O(23)) was a tetragonal superstructure of perovskite.     

Synthesis and crystal chemistry of two new fluorite-related bismuth phosphates, Bi(4.25)(PO4)2O(3.375) and Bi5(PO4)2O4.5, in the Series Bi4+x(PO4)2O3+3x/2 (0.175 < or = x < or = 1)

Two new phosphates, Bi(4.25)(PO4)2O(3.375) and Bi(5)(PO(4))(2)O(4.5), have been analyzed by single-crystal X-ray diffraction in the series Bi(4+x)(PO4)2O(3+3x/2) (0.175 < or = x < or = 1). The syntheses of the compositions ranging from x = 0.175 to 0.475 were carried out by the ceramic route. The compositions from x = 0.175 to 0.475 form a solid solution with a structure similar to that of Bi(4.25)(PO4)2O(3.375), while Bi(5)(PO4)2O(4.5) was isolated from a mixture of two phases. Both of the phases form fluorite-related structures but, nevertheless, differ from each other with respect to the arrangement of the bismuth atoms. The uniqueness in the structures is the appearance of isolated PO(4) tetrahedra separated by interleaving [Bi2O2] units. ac impedance studies indicate conductivity on the order of 10(-5) S cm(-1) for Bi(4.25)(PO4)2O(3.375). Crystal data: Bi(4.25)(PO4)2O(3.375), triclinic, space group P (No. 1), with a = 7.047(1) A, b = 9.863(2) A, c = 15.365(4) A, alpha = 77.604(4) degrees, beta = 84.556(4) degrees, gamma = 70.152(4) degrees, V = 980.90(4) A3, and Z = 4; Bi(5)(PO4)2O(4.5), monoclinic, space group C2/c (No. 15), with a = 13.093(1) A, b = 5.707(1) A, c = 15.293(1) A, beta = 98.240(2) degrees, V = 1130.95(4) A(3), and Z = 8.     

Intermolecular proton binding in the presence of a large electric dipole: Ar-tagged vibrational predissociation spectroscopy of the CH3CN x H+ x OH2 and CH3CN x D+ x OD2 complexes

We report Ar-predissociation vibrational spectra of the binary proton-bound hydrates of acetonitrile (AN), AN x H(+) x OH(2) and AN x D(+) x OD(2), in the 600-3800 cm(-1) energy range. This complex was specifically chosen to explore the nature of the intermolecular proton bond when there is a large difference between the electric dipole moments of the two tethered molecules. Sharp, isotope-dependent bands in the vicinity of 1000 cm(-1) are traced to AN x H(+) x OH(2) vibrations involving the parallel displacement of the shared proton along the heavy atom axis, nu(sp)(parallel). These transitions lie much lower in energy than anticipated by a recently reported empirical trend which found the nu(sp)(parallel) fundamentals to be strongly correlated with the difference in proton affinities (DeltaPA) between the two tethered molecules (Roscioli et al., Science, 2007, 316, 249). The different behavior of the AN x H(+) x OH(2) complex is discussed in the context of the recent theoretical prediction (Fridgen, J. Phys. Chem A., 2006, 110, 6122) that a large disparity in dipole moments would lead to such a deviation from the reported (DeltaPA) trend.     

Single crystalline commensurate metallic assemblages of pi-slabs and CdI2-type layers: synthesis and properties of beta-(EDT-TTF-I2)2[Pb5/6 square 1/6I2](3) and beta-(EDT-TTF-I2)2[Pb2/3+xAg1/3-2x square xI2]3, x = 0.05

The ability of I...I van der Waals interactions to direct the self-assembly of slabs of the radical cation of ethylenedithio-1,2-diiodo-tetrathiafulvalene, EDT-TTF-I(2), and polymeric lead iodide covalent anionic layers is demonstrated by the synthesis of single crystals of beta-(EDT-TTF-I(2))(2)(.+)[(Pb(5/6) square (1/6)I(2))(1/3-)](3), triclinic, P-1, a = 7.7818(8), b = 7.9760(8), c = 19.9668(2) A, alpha = 82.409(12), beta = 85.964(12), gamma = 61.621(11) degrees, V = 1080.76(19) A(3), R1, wR2 = 0.0459, 0.0947; and beta-(EDT-TTF-I(2))(2)(.+)[(Pb(2/3+x)Ag(1/3-2x)square(x)I(2))(1/3-)](3), x approximately 0.05, triclinic, P-1, a = 7.7744(8), b = 7.9193(8), c = 19.834(2) A, alpha = 87.189(12), beta = 83.534(12), gamma = 61.602(11) degrees, V = 1067.4(2) A(3), R1, wR2 = 0.0508, 0.0997. The state-of-the-art, combined microprobe and structural analysis of the metal site vacancies and occupancies patterns reveal a commensurate organic-inorganic interface and point out the importance of halogen.halogen van der Waals interactions to future studies aiming at directing interface topologies. The electronic structure, room-temperature metallic character and metal-insulator transition at ca. 70 K of the two-dimensional organic slabs are retained upon alloying of the inorganic sublattice with monocations. The room-temperature conductivity of the metallic lead-silver alloy is 2 orders of magnitude larger than that of beta-(EDT-TTF-I(2))(2)(.+)[(Pb(5/6) square (1/6)I(2))(1/3-)](3). This calls for the study of materials with diverse alloying patterns with metal cations of different nature and charge.