Further Examples of the P-O-P Connection in Borophosphates: Synthesis and Characterization of Li(2) Cs(2) B(2) P(4) O(15) , LiK(2) BP(2) O(8) , and Li(3) M(2) BP(4) O(14) (M=K, Rb)

A new series of anhydrous mixed alkali-metal borophosphates-Li(2) Cs(2) B(2) P(4) O(15) (1), LiK(2) BP(2) O(8) (2), Li(3) K(2) BP(4) O(14) (3), and Li(3) Rb(2) BP(4) O(14) (4)-have been successfully synthesized by using the conventional solid-state reaction method. Compound 1 contains a novel fundamental building unit (FBU), [B(4) P(8) O(30) ], with B/P=1:2. Compound 2 contains an FBU of [B(2) P(4) O(16) ] with B/P=1:2. Compounds 3 and 4 are isotypic, and they have a [B(P(2) O(7) )(2) ] unit as their FBU. In all four compounds, their FBUs are connected through corner sharing to generate layered anionic partial structures, and then further linked with metallic polyhedra to form three-dimensional (3D) frameworks. Most interestingly, three of the four compounds contain direct P-O-P connections in their structures, which is extremely rare among borophosphates. Thermal analyses, IR spectroscopy, and UV/Vis/near-IR diffuse reflectance spectroscopy have also been performed on the four title compounds.     

Fluorescence excitation spectra of the b (1)Pi(u), b(') (1)Sigma(u) (+), c(n) (1)Pi(u), and c(n) (') (1)Sigma(u) (+) states of N(2) in the 80-100 nm region

Fluorescence excitation spectra produced through photoexcitation of N(2) using synchrotron radiation in the spectral region between 80 and 100 nm have been studied. Two broadband detectors were employed to simultaneously monitor fluorescence in the 115-320 nm and 300-700 nm regions, respectively. The peaks in the vacuum ultraviolet fluorescence excitation spectra are found to correspond to excitation of absorption transitions from the ground electronic state to the b (1)Pi(u), b(') (1)Sigma(u) (+), c(n) (1)Pi(u) (with n=4-8), c(n) (') (1)Sigma(u) (+) (with n=5-9), and c(4) (')(v('))(1)Sigma(u) (+) (with v(')=0-8) states of N(2). The relative fluorescence production cross sections for the observed peaks are determined. No fluorescence has been produced through excitation of the most dominating absorption features of the b-X transition except for the (1,0), (5,0), (6,0), and (7,0) bands, in excellent agreement with recent lifetime measurements and theoretical calculations. Fluorescence peaks, which correlate with the long vibrational progressions of the c(4) (') (1)Sigma(u) (+) (with v(')=0-8) and the b(') (1)Sigma(u) (+) (with v(') up to 19), have been observed. The present results provide important information for further unraveling of complicated and intriguing interactions among the excited electronic states of N(2). Furthermore, solar photon excitation of N(2) leading to the production of c(4) (')(0) may provide useful data required for evaluating and analyzing dayglow models relevant to the interpretation of c(4) (')(0) in the atmospheres of Earth, Jupiter, Saturn, Titan, and Triton.     

Hyperfine structures of the 2 (3)Sigma(g) (+), 3 (3)Sigma(g) (+), and 4 (3)Sigma(g) (+) states of Na(2)

The hyperfine structures of the 2 (3)Sigma(g) (+), 3 (3)Sigma(g) (+), and 4 (3)Sigma(g) (+) states of Na(2) have been resolved with sub-Doppler continuous wave perturbation facilitated optical-optical double resonance spectroscopy via A (1)Sigma(u) (+) approximately b (3)Pi(u) mixed intermediate levels. The hyperfine patterns of these three states are similar. The hyperfine splittings of the low rotational levels are all very close to the case b(betaS) limit. As the rotational quantum number increases, the hyperfine splittings become more complicated and the coupling cases become intermediate between cases b(betaS) and b(beta J) due to spin-rotation interaction. We present a detailed analysis of the hyperfine structures of these three (3)Sigma(g) (+) states, employing both case b(betaS) and b(beta J) coupling basis sets. The results show that the hyperfine splittings of the (3)Sigma(g) (+) states are mainly due to the Fermi-contact interaction. The Fermi contact constants for the two d sigma Rydberg states, the 2 (3)Sigma(g) (+) and 4 (3)Sigma(g) (+), are 245+/-5 MHz and 225+/-5 MHz, respectively, while the Fermi contact constant of the s sigma 3 (3)Sigma(g) (+) Rydberg state is 210+/-5 MHz. The diagonal spin-spin and spin-rotation constants, and nuclear spin-electronic spin dipolar interaction parameters of the 3 (3)Sigma(g) (+) and 4 (3)Sigma(g) (+) states are also obtained.     

OH(3) (-) and O(2)H(5) (-) double Rydberg anions: predictions and comparisons with NH(4) (-) and N(2)H(7) (-)

A low barrier in the reaction pathway between the double Rydberg isomer of OH(3) (-) and a hydride-water complex indicates that the former species is more difficult to isolate and characterize through anion photoelectron spectroscopy than the well known double Rydberg anion (DRA), tetrahedral NH(4) (-). Electron propagator calculations of vertical electron detachment energies (VEDEs) and isosurface plots of the electron localization function disclose that the transition state's electronic structure more closely resembles that of the DRA than that of the hydride-water complex. Possible stabilization of the OH(3) (-) DRA through hydrogen bonding or ion-dipole interactions is examined through calculations on O(2)H(5) (-) species. Three O(2)H(5) (-) minima with H(-)(H(2)O)(2), hydrogen-bridged, and DRA-molecule structures resemble previously discovered N(2)H(7) (-) species and have well separated VEDEs that may be observable in anion photoelectron spectra.     

Rhodium-catalyzed dehydrocoupling of the sterically encumbered phosphine-borane adduct tBu(2)PH.BH(3): synthesis of the linear dimers tBu(2)PH-BH(2)-tBu(2)P-BH(3) and tBu(2)PH-BH(2)-tBu(2)P-BH(2)Cl

The dehydrocoupling of the sterically hindered phosphine-borane adduct tBu(2)PH.BH(3) above 140 degrees C is catalyzed by the rhodium complexes [Rh(1,5-cod)(2)][OTf] or Rh(6)(CO)(16) to give the four-membered chain tBu(2)PH-BH(2)-tBu(2)P-BH(3) (1), which was isolated in 60% yield and characterized by multinuclear NMR spectroscopy, mass spectrometry, and elemental analysis. Thermolysis of 1 in the temperature range 175-180 degrees C led to partial decomposition and the formation of tBu(2)PH.BH(3). When the dehydrocoupling of tBu(2)PH.BH(3) was performed in the presence of [[Rh(mu-Cl)(1,5-cod)](2)] or RhCl(3) hydrate, the chlorinated compound tBu(2)PH-BH(2)-tBu(2)P-BH(2)Cl (2) was formed which could not be obtained free of 1. The molecular structures of tBu(2)PH.BH(3), tBu(2)PH-BH(2)-tBu(2)P-BH(3) (1), and tBu(2)PH-BH(2)-tBu(2)P-BH(2)Cl (2) together with 1 were determined by single-crystal X-ray diffraction studies.     

Solid state NMR characterization of individual compounds and solid solutions formed in Sc(2)O(3)--V(2)O(5)--Nb(2)O(5)--Ta(2)O(5) system

In this study, (51)V, (45)Sc and (93)Nb MAS NMR combined with satellite transition spectroscopy analysis were used to characterize the complex solid mixtures: VNb(9(1-x))Ta(9x)O(25), ScNb((1-x))Ta(x)O(4) and ScNb(2(1-x))Ta(2x)VO(9) (x = 0, 0.3, 0.5, 0.7, 1.0). This led us to describe the structures of Sc and V sites. The conclusions were based on accurate values for (51)V quadrupole coupling and chemical shift tensors obtained with (51)V MAS NMR/SATRAS for VNb(9)O(25), VTa(9)O(25) and ScVO(4). The (45)Sc NMR parameters have been obtained for Sc(2)O(3), ScVO(4), ScNbO(4) and ScTaO(4). On the basis of (45)Sc NMR and data available from literature, the ranges of the (45)Sc chemical shift have been established for ScO(6) and ScO(8). The gradual change of the (45)Sc and (51)V NMR parameters with x confirms the formation of solid solutions in the process of synthesis of VNb(9(1-x))Ta(9x)O(25) and ScNb((1-x))Ta(x)O(4), in contrast to ScNb(2(1-x))Ta(2x)VO(9). The cation sublattice of ScNb((1-x))Ta(x)O(4) is found to be in octahedral coordination. The V sites in VNb(9(1-x))Ta(9x)O(25) are present in the form of slightly distorted tetrahedra. The (93)Nb NMR parameters have been obtained for VNb(9)O(25).     

Bis(trifluoroacetyl) peroxide, CF(3)C(O)OOC(O)CF(3)

Pure, highly explosive CF(3)C(O)OOC(O)CF(3) is prepared for the first time by low-temperature reaction between CF(3)C(O)Cl and Na(2)O(2). At room temperature CF(3)C(O)OOC(O)CF(3) is stable for days in the liquid or gaseous state. The melting point is -37.5 degrees C, and the boiling point is extrapolated to 44 degrees C from the vapor pressure curve log p = -1875/T + 8.92 (p/mbar, T/K). Above room temperature the first-order unimolecular decay into C(2)F(6) + CO(2) occurs with an activation energy of 129 kJ mol(-1). CF(3)C(O)OOC(O)CF(3) is a clean source for CF(3) radicals as demonstrated by matrix-isolation experiments. The pure compound is characterized by NMR, vibrational, and UV spectroscopy. The geometric structure is determined by gas electron diffraction and quantum chemical calculations (HF, B3PW91, B3LYP, and MP2 with 6-31G basis sets). The molecule possesses syn-syn conformation (both C=O bonds synperiplanar to the O-O bond) with O-O = 1.426(10) A and dihedral angle phi(C-O-O-C) = 86.5(32) degrees. The density functional calculations reproduce the experimental structure very well.     

New layered materials: syntheses, structures, and optical properties of K(2)TiCu(2)S(4), Rb(2)TiCu(2)S(4), Rb(2)TiaAg(2)S(4), Cs(2)TiAg(2)sS(4), and Cs(2)TiCu(2)Se(4)

The new compounds K(2)TiCu(2)S(4), Rb(2)TiCu(2)S(4), Rb(2)TiAg(2)S(4), Cs(2)TiAg(2)S(4), and Cs(2)TiCu(2)Se(4) have been synthesized by the reactions of A(2)Q(3) (A = K, Rb, Cs; Q = S, Se) with Ti, M (M = Cu or Ag), and Q at 823 K. The compounds Rb(2)TiCu(2)S(4), Cs(2)TiAg(2)S(4), and Cs(2)TiCu(2)Se(4) are isostructural. They crystallize with two formula units in space group P4(2)/mcm of the tetragonal system in cells of dimensions a = 5.6046(4) A, c = 13.154(1) A for Rb(2)TiCu(2)S(4), a =6.024(1) A, c = 13.566(4) A for Cs(2)TiAg(2)S(4), and a =5.852(2) A, c =14.234(5) A for Cs(2)TiCu(2)Se(4) at 153 K. Their structure is closely related to that of Cs(2)ZrAg(2)Te(4) and comprises [TiM(2)Q(4)(2)(-)] layers, which are separated by alkali metal atoms. The [TiM(2)Q(4)(2)(-)] layer is anti-fluorite-like with both Ti and M atoms tetrahedrally coordinated to Q atoms. Tetrahedral coordination of Ti(4+) is rare in the solid state. On the basis of unit cell and space group determinations, the compounds K(2)TiCu(2)S(4) and Rb(2)TiAg(2)S(4) are isostructural with the above compounds. The band gaps of K(2)TiCu(2)S(4), Rb(2)TiCu(2)S(4), Rb(2)TiAg(2)S(4), and Cs(2)TiAg(2)S(4) are 2.04, 2.19, 2.33, and 2.44 eV, respectively, as derived from optical measurements. From band-structure calculations, the optical absorption for an A(2)TiM(2)Q(4) compound is assigned to a transition from an M d and Q p valence band (HOMO) to a Ti 3d conduction band.     

Synthesis and Crystal Structure of Trans-diaquabis(hexamethylenetetramine-N)bis(isothiocyanato)cobalt(Ⅱ) trans-tetraaquabis(isothiocyanato)cobalt(Ⅱ) dihydrate

1 INTRODUCTION Supramolecular compounds assembled by coordination covalent bonding or hydrogen bonding are of considerable interest due to their potential applications in developing new materials with magnetic, optical and catalytic properties[1]. One of the synthesis methods used to construct the functional compounds is that octahedral metal ion connects to polydentate ligand such as 4, 4?bipyridine, pyrazine and so on to form multi-dimensional supramolecular polymer[2]. Hmt (hexamethyl…     

The Synthesis and Structure of (1-(Diphenylphosphino)-1 - (Phenylthio)Ferrocene)Tricarbonyliron(O) (ptppf)Fe(CO)3

The complex (ptppf)Fe(CO)₃ has been prepared in high yield by the reaction of ptppf, l-(diphenyl-phosphino)-l'-(phenylthio)ferrocene, with (cis-cyclooctene)₂-Fe(CO)₃ in THF at ?60°C. The complex has been characterized by IR, ³¹P NMR, mass spectrometry and single-crystal X-ray diffraction. This compound is the first example of a ferrocenyl ligand having both sulfur and phosphorus donor atoms bound to a Fe(CO)₃ moiety. X-ray crystallography shows that the two cyclopentadienyl rings are approximately eclipsed, a rotation of 13° from exactly eclipsed conformation. The tricarbonyl iron center has a trigonal bipyramidal geometry with sulfur occupying the equatorial site and phosphorus the axial site. Crystals of (ptppf)Fe(CO)₃ are monoclinic, with a = 11.645(2), b = 14.304(1), c = 17.075(2) Å,β = 109.23(3)°, Z = 4, and space group P 2₁/n. The structure was solved according to the heavy-atom method and refined by full-matrix least-squares procedures to R = 0.037 for 2098 reflections with I ≥ 2.5σ(I).     

Spectroscopic properties of Er(3+)/Yb(3+) co-doped Bi(2)O(3)-B(2)O(3)-GeO(2) glasses

Er(3+)/Yb(3+) co-doped 60Bi(2)O(3)-(40 - x)B(2)O(3)-xGeO(2) (BBG; x=0, 5, 10, 15 mol%) glasses that are suitable for fiber lasers, amplifiers have been fabricated and characterized. The absorption spectra, emission spectra, and lifetime of the (4)I(13/2) level and quantum efficiency of Er(3+):(4)I(13/2) --> (4)I(15/2) transition were measured and calculated. With the substitution of GeO(2) for B(2)O(3), both Delta lambda(eff) and sigma(e) decrease from 75 to 71 nm and 9.88 to 8.12 x 10(-21) cm(2), respectively. The measured lifetime of the (4)I(13/2) level and quantum efficiency of Er(3+):(4)I(13/2) --> (4)I(15/2) transition increase from 1.18 to 1.5 ms and 36.2% to 43.2%, respectively. The emission spectra of Er(3+):(4)I(13/2) --> (4)I(15/2) transition was also analyzed using a peak-fit routine, and an equivalent four-level system was proposed to estimate the stark splitting for the (4)I(15/2) and (4)I(13/2) levels of Er(3+) in the BBG glasses. The results indicate that the (4)I(13/2) --> (4)I(15/2) emission of Er(3+) can be exhibit a considerable broadening due to a significant enhance the peak A, and D emission.     

Synthesis of bis(diethyldithiocarbamato)manganese(II) and tris(diethyldithiocarbamato)manganese(III)

An ideal undergraduate introduction to the challenges of synthesis and characterization of air-sensitive compounds is accomplished in the preparation of bis(diethyldithiocarbamato)manganese(II). This economical experiment employs a glovebag, low-cost and low-toxicity chemicals, and is completed in one undergraduate laboratory period. For comparison purposes, the synthesis and characterization of air-stable tris(diethyldithiocarbamato)manganese(III) is also described.     

Reactions of CO(2) and CS(2) with 1,2-bis(di-tert-butylphosphino)ethane complexes of nickel(0) and nickel(I)

Reaction of CS(2) with [(dtbpe)Ni](2)(η(2),μ-C(6)H(6)) (1; dtbpe =1,2-bis(di-tert-butylphosphino)ethane) in toluene gives the carbon disulfide complex (dtbpe)Ni(η(2)-CS(2)) (2), characterized by standard spectroscopic methods and X-ray crystallography. Reaction of CS(2) with the Ni(I) complex (dtbpe)Ni(OSO(2)CF(3)) gives the diamagnetic, trimetallic cluster [{(dtbpe)Ni(κ(1),η(2)-CS(2))}(2)(dtbpe)Ni][SO(3)CF(3)](2) (3-OTf). The solid-state structure of 3-OTf reveals that the two CS(2) ligands bind η(2) to two (dtbpe)Ni centers and κ(1) to the third, unique (dtbpe)Ni in the complex dication, and NMR spectroscopic data indicate that this structure is maintained in solution. Oxidation of 2 by ferrocenium hexafluorophosphate affords the identical trimetallic complex dication as the PF(6)(-) salt, [{(dtbpe)Ni(κ(1),η(2)-CS(2))}(2)(dtbpe)Ni][PF(6)](2) (3-PF(6)). These results are consistent with the intermediacy of a Ni(I)-CS(2) complex, [(dtbpe)Ni(CS(2))(+)], that is unstable with respect to disproportionation. Reaction of 1 with one equivalent of CO(2) provides the carbon dioxide adduct (dtbpe)Ni(η(2)-CO(2)) (4), that was also crystallographically characterized. Thermolysis of 4 in benzene solution at 80 °C results in reduction of the CO(2) ligand to CO, trapped as (dtbpe)Ni(CO)(2), and partial oxidation of a dtbpe ligand to give O═P(tert-Bu)(2)CH(2)CH(2)P(tert-Bu)(2).     

NMR Characterization of the Na(3)AlP(3)O(9)N and Na(2)Mg(2)P(3)O(9)N Nitridophosphates: Location of the (NaAl)/Mg(2) Substitution

We report a solid state nuclear magnetic resonance study of (23)Na, (27)Al, and (31)P in two crystalline nitridophosphate phases, Na(3)AlP(3)O(9)N and Na(2)Mg(2)P(3)O(9)N, including two-dimensional multiple-quantum magic angle spinning (MQ-MAS) experiments on (23)Na to separate overlapping lines. The previously described single-crystal structure of Na(3)AlP(3)O(9)N gives crystallographic examples of Al(OP)(6) and P(O[Al,Na])(2)(ONa)(N[P,Na]) environments and three different environments of sodium: two Na(O)(6) and one Na(O)(6)(N). From these observations we characterize the modification of the local environment of phosphorus and show that Mg only substitutes Na in the Na2 site of the Na(2)Mg(2)P(3)O(9)N structure.     

Crystal structure of (acetylacetonato) (dicarbonyl)iridium(I)

The structure of Ir(CO)₂(acac) is determined by XRD at room temperature. Crystallographic data for C₇H₇IrO₄ are: a = 6.4798(5) ?, b = 7.7288(5) ?, c = 9.1629(10) ?, α = 105.738(2)°, β = 90.467(3)°, γ = 100.658(2)°, space group 1, P , V= 433.24(6) ?³, Z = 2, d _calc = 2.662 g/cm³, R = 0.0167. The structure is built of isolated mononuclear molecules. The central iridium atom has a square coordination environment formed by two oxygen atoms that belong to the acetylacetonate ligand and two carbon atoms of carbonyl groups. The average Ir-O and Ir-C bond lengths are 2.045(3) ? and 1.832(6) ? respectively. Molecules are stacked in such a way that the planes of coordination squares turn out to be parallel to the Ir...Ir distances between the nearest neighbors in the stack of 3.242 ? and 3.260 ?. Original Russian Text Copyright ? 2009 by K. V. Zherikova, N. V. Kuratieva, and N. B. Morozova __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 595–597, May–June, 2009.     

Syntheses and structures of the infinite chain compounds Cs(4)Ti(3)Se(13), Rb(4)Ti(3)S(14), Cs(4)Ti(3)S(14), Rb(4)Hf(3)S(14), Rb(4)Zr(3)Se(14), Cs(4)Zr(3)Se(14), and Cs(4)Hf(3)Se(14)

The alkali metal/group 4 metal/polychalcogenides Cs(4)Ti(3)Se(13), Rb(4)Ti(3)S(14), Cs(4)Ti(3)S(14), Rb(4)Hf(3)S(14), Rb(4)Zr(3)Se(14), Cs(4)Zr(3)Se(14), and Cs(4)Hf(3)Se(14) have been synthesized by means of the reactive flux method at 823 or 873 K. Cs(4)Ti(3)Se(13) crystallizes in a new structure type in space group C(2)(2)-P2(1) with eight formula units in a monoclinic cell at T = 153 K of dimensions a = 10.2524(6) A, b = 32.468(2) A, c = 14.6747(8) A, beta = 100.008(1) degrees. Cs(4)Ti(3)Se(13) is composed of four independent one-dimensional [Ti(3)Se(13)(4-)] chains separated by Cs(+) cations. These chains adopt hexagonal closest packing along the [100] direction. The [Ti(3)Se(13)(4-)] chains are built from the face- and edge-sharing of pentagonal pyramids and pentagonal bipyramids. Formal oxidation states cannot be assigned in Cs(4)Ti(3)Se(13). The compounds Rb(4)Ti(3)S(14), Cs(4)Ti(3)S(14), Rb(4)Hf(3)S(14), Rb(4)Zr(3)Se(14), Cs(4)Zr(3)Se(14), and Cs(4)Hf(3)Se(14) crystallize in the K(4)Ti(3)S(14) structure type with four formula units in space group C(2)(h)()(6)-C2/c of the monoclinic system at T = 153 K in cells of dimensions a = 21.085(1) A, b = 8.1169(5) A, c = 13.1992(8) A, beta = 112.835(1) degrees for Rb(4)Ti(3)S(14);a = 21.329(3) A, b = 8.415(1) A, c = 13.678(2) A, beta = 113.801(2) degrees for Cs(4)Ti(3)S(14); a = 21.643(2) A, b = 8.1848(8) A, c = 13.331(1) A, beta = 111.762(2) degrees for Rb(4)Hf(3)S(14); a = 22.605(7) A, b = 8.552(3) A, c = 13.880(4) A, beta = 110.919(9) degrees for Rb(4)Zr(3)Se(14); a = 22.826(5) A, b = 8.841(2) A, c = 14.278(3) A, beta = 111.456(4) degrees for Cs(4)Zr(3)Se(14); and a = 22.758(5) A, b = 8.844(2) A, c = 14.276(3) A, beta = 111.88(3) degrees for Cs(4)Hf(3)Se(14). These A(4)M(3)Q(14) compounds (A = alkali metal; M = group 4 metal; Q = chalcogen) contain hexagonally closest-packed [M(3)Q(14)(4-)] chains that run in the [101] direction and are separated by A(+) cations. Each [M(3)Q(14)(4-)] chain is built from a [M(3)Q(14)] unit that consists of two MQ(7) pentagonal bipyramids or one distorted MQ(8) bicapped octahedron bonded together by edge- or face-sharing. Each [M(3)Q(14)] unit contains six Q(2)(2-) dimers, with Q-Q distances in the normal single-bond range 2.0616(9)-2.095(2) A for S-S and 2.367(1)-2.391(2) A for Se-Se. The A(4)M(3)Q(14) compounds can be formulated as (A(+))(4)(M(4+))(3)(Q(2)(2-))(6)(Q(2-))(2).     

Acidites et complexes des acides (alkyl-et aminoalkyl-) phosphoniques-IV: acides aminoalkylphosphoniques R(1)R(2)N(CH(2))(n)CR(3)R(4)PO(3)H(2)

The acids under study differed from one another in length of the carbon chain [N + H(3)(CH(2))(n)PO(3)H(-) for n = 1, 2, 3], substitution on the nitrogen atom [R(1)R(2)N + HCH(2)PO(3)H(-) for R(1) = H; R(2) = Me, Et and R(1) = R(2)= Me, Et] or extent of branching on the carbon atom adjacent to functional groups [N + H(3)CR(3)R(4)PO(3)H(-) for R(3) = H; R(4) = Me, Et, nPr, iPr, nBu and R(3) = R(4) = Me]. Acidity constants and overall stability constants of complexes formed with Ca(II), Mg(II), Co(II), Ni(II), Cu(II), Zn(II) were obtained with the multiparametric refinement programs MUPROT and MUCOMP, applied to potentiometric data, obtained at 25 degrees , in a 0.1M potassium nitrate medium. In the most general case, the existing species are MHA(+), MA, M(OH)A(-), MH(2)A(2), MHA(-)(2) and MA(2-)(2), where A(2-) stands for the fully ionized ligand; preliminary examination of results points out some predominant microscopic forms.     

Photoelectron spectroscopy and density functional theory study of TiAlO(y) (-) (y=1-3) and TiAl(2)O(y) (-) (y=2-3) clusters

Small titanium-aluminum oxide clusters, TiAlO(y) (-) (y=1-3) and TiAl(2)O(y) (-) (y=2-3), were studied by using anion photoelectron spectroscopy. The adiabatic detachment energies of TiAlO(y) (-) (y=1-3) were estimated to be 1.11±0.05, 1.70±0.08, and 2.47±0.08eV based on their photoelectron spectra; those of TiAl(2)O(2) (-) and TiAl(2)O(3) (-) were estimated to be 1.17±0.08 and 2.2±0.1eV, respectively. The structures of these clusters were determined by comparison of density functional calculations with the experimental results. The structure of TiAlO(-) is nearly linear with the O atom in the middle. That of TiAlO(2) (-) is a kite-shaped structure. TiAlO(3) (-) has a kite-shaped TiAlO(2) unit with the third O atom attaching to the Ti atom. TiAl(2)O(2) (-) has two nearly degenerate Al-O-Ti-O-Al chain structures that can be considered as cis and trans forms. TiAl(2)O(3) (-) has two low-lying isomers, kite structure and book structure. The structures of these clusters indicate that the Ti atom tends to bind to more O atoms.     

Reduction of (imine)Pt(IV) to (imine)Pt(II) complexes with carbonyl-stabilized phosphorus ylides

A novel method is reported for generation of the difficult-to-obtain (imine)Pt(II) compounds that involves reduction of the corresponding readily available Pt(IV)-based imines by carbonyl-stabilized phosphorus ylides, Ph3P=CHCO2R, in nonaqueous media. The reaction between neutral (imino)Pt(IV) compounds [PtCl4[NH=C(Me)ON=CR1R2]2] [R1R2 = Me2, (CH2)4, (CH2)5, (Me)C(Me)=NOH], [PtCl4[NH=C(Me)ONR2]2] (R = Me, Et, CH2Ph), (R1 = H; R2 = Ph or C6H4Me; R3 = Me) as well as anionic-type platinum(IV) complexes (Ph3PCH2Ph)[PtCl5[NH=C(Me)ON=CR2]] [R2 = Me2, (CH2)4, (CH2)5] and 1 equiv of Ph3P=CHCO2R (R = Me, Et) proceeds under mild conditions (ca. 4 h, room temperature) to give selectively the platinum(II) products (in good to excellent isolated yields) without further reduction of the platinum center. All thus prepared compounds (excluding previously described Delta4-1,2,4-oxadiazoline complexes) were characterized by elemental analyses, FAB mass spectrometry, IR and 1H, 13C[1H], 31P[1H] and 195Pt NMR spectroscopies, and X-ray single-crystal diffractometry, the latter for [PtCl2[NH=C(Me)ON=CMe2]2] [crystal system tetragonal, space group P4(2)/n (No. 86), a = b = 10.5050(10) A, c = 15.916(3) A] and (Ph3PCH2CO2Me)[PtCl3(NCMe)] [crystal system orthorhombic, space group Pna2(1) (No. 33), a = 19.661(7) A, b = 12.486(4) A, c = 10.149(3) A]. The reaction is also extended to a variety of other Pt(II)/Pt(IV) couples, and the ylides Ph3P=CHCO2R are introduced as mild and selective reducing agents of wide applicability for the conversion of Pt(IV) to Pt(II) species in nonaqueous media, a route that is especially useful in the case of compounds that cannot be prepared directly from Pt(II) precursors, and for the generation of systematic series of Pt(II)/Pt(IV) complexes for biological studies.     

Exploratory synthesis in molten salts: role of flux basicity in the stabilization of the complex thiogermanates Cs(4)Pb(4)Ge(5)S(16), K(2)PbGe(2)S(6), and K(4)Sn(3)Ge(3)S(14)

The influence of the Lewis basicity of alkali polysulfide fluxes (A(2)S(x)) (A = alkali) as a function of x on the respective reactivities of Pb and Sn with Ge was studied and found to be strong. Cs(4)Pb(4)Ge(5)S(16), K(2)PbGe(2)S(6), and K(4)Sn(3)Ge(3)S(14) could be prepared only under low basicity with S/A(2)S ratios of > or =11. These compounds display complex frameworks and are semiconductors. Cs(4)Pb(4)Ge(5)S(16) is luminescent with red emission.