Infrared spectra of group 14 hydrides in solid hydrogen: experimental observation of PbH4, Pb2H2, and Pb2H4

Laser-ablated Si, Ge, Sn, and Pb atoms have been co-deposited with pure hydrogen at 3.5 K to form the group 14 hydrides. The initial SiH(2) product reacts completely to SiH(4), whereas substantial proportions of GeH(2), SnH(2), and PbH(2) are trapped in solid hydrogen. Further hydrogen atom reactions form the trihydride radicals and tetrahydrides of Ge, Sn, and Pb. The observation of PbH(4) at 1815 cm(-)(1) and PbD(4) at 1302 cm(-)(1) is in agreement with the prediction of quantum chemical calculations for these unstable tetrahydride analogues of methane. In addition, new absorptions are observed for Pb(2)H(2) and Pb(2)H(4), which have dibridged structures based on quantum chemical calculations.     

ChemInform Abstract: H-Bridged Structures for Tetrahedranes A4H4 (A: C,Si, Ge,Sn, and Pb).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Molecular Structure and Thermal Stability of B2H4 and B2H+ 4 Species.

B₂H₄ is produced by reaction of B₂H₆ with fluorine atoms generated in a microwave discharge.     

ChemInform Abstract: Preparation and Crystal Structure of a New Acentric Caesium Gallium Hydrogen Phosphate Containing Phosphoric Acid,Cs2Ga(H2PO4)(HPO4)2. times.H3PO4×0.5 H2O.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Two Caesium Vanadium Hydrogenphosphates,with Tunnelled Structures: Cs2V2O3(PO4)(HPO4) and Cs2 [(VO)3(HPO4)4(H2O)] ·H2O.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Crystal Structure and Spectroscopic Studies of LiNH4(H2PO4)2 — A New Solid Acid in the LiH2PO4—NH4H2PO4 System.

LiNH₄(H₂PO₄)₂ is prepared from an equimolar aqueous mixture of NH₄H₂PO₄ and LiH₂PO₄ by slow evaporation at 25 °C.     

Die Kristallstruktur des Bleicyclotetraphosphat-4-Hydrats,Pb2P4O12 · 4H2O

Crystal Structure of Lead Cyclotetraphosphate-4-Hydrate, Pb₂P₄O₁₂·4 H₂O Pb₂P₄O₁₂·4 H₂O is the starting product of a series of solid state reactions with the final product cyclooctaphosphate. Pb₂P₄O₁₂·4 H₂O crystallizes in the monoclinic space group P2₁/n, with a = 8.07 ± 0.02, b = 11.76 ± 0.03, c = 7.50 ± 0.02 Å and β = 108.2 ± 0.3°. The crystal structure has been solved by Patterson and Fourier methods and refined by least squares calculations to an R-index of 0.07. The structure consists of P₄0₁₂^4? ringanions, which are connected by Pb and hydrogen bonds. Lead is coordinated by eight oxygen atoms.     

Eremophilane esters of Robinsonecio gerberifolius and their rearranged products. Study of the coupling constants (2)J(H, H), (3)J(H, H) and (4)J(H, H)

In the course of the basic hydrolysis of four eremophilane esters isolated from Robinsonecio gerberifolius, some rearrangements, eliminations, and additions occurred. Five compounds were obtained, three of them not previously described. Additionally, a new sesquiterpene was produced by autooxidation of compound 1. The (1)H and (13)C NMR spectra of these compounds were completely assigned by utilization of HMQC, HMBC, COSY, DEPT, and NOESY techniques. The long-range coupling constants of the peroxide 10 are reported, and all its coupling constants (2)J(H, H), (3)J(H, H), and (4)J(H, H) are calculated at the B3LYP/6-31G(d,p) level of theory. Their magnitude is explained in terms of electronic delocalization and the additivity of stereoelectronic effects.     

Stabilization Studies on Divalent Five‐Membered Rings C4H4C,C4H4Si,C4H4Ge,C4H4Sn,and C4H4Pb

Energy differences, ΔX_S‐t (X = E, H and G) (ΔX_S‐t = X_(singlet)‐X_(triplet)) between singlet (s) and triplet (t) states are calculated at B3LYP/6‐311++G (3df,2p). The DFT calculations show that the triplet state of C₄H₄C is a ground state with planar conformer respect to its corresponding nonplanar singlet state. Both singlet and triplet states of C₄H₄M (M = Si, Ge, Sn and Pb) have a planar conformer with the singlet ground state. Four isodesmic reactions are presented for determining the stability energies, SE. NICS calculations are carried out for C₄H₄M to determine the aromatic character.     

Synthesis,Crystal Structure,and Characterization of A New Adduct Bis-(2-Amino-3-Benzyloxypyridinium) Selenate Monohydrate [C12H13N2O]2SeO4.H2O

Abstract

A new adduct bis-(2-amino-3-benzyloxypyridinium) selenate monohydrate, [C₁₂H₁₃N₂O]₂SeO₄.H₂O, has been synthesized by slow evaporation at room temperature using 2-amino-3-benzyloxypyridine as the structure-directing agent. The structure, determined by single-crystal X-ray diffraction at 298 K, can be described as organic-inorganic tunnels with different forms built by infinite inorganic chains parallel to the c axis and connected to the organic cations. In this atomic arrangement, hydrogen bonds and van der Waals interactions between the different species play an important role in the tri-dimensional network cohesion. Solid-state ¹³C and ⁷⁷Se MAS NMR spectroscopy results are in agreement with the X-ray structure.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures and tables.]     

ChemInform Abstract: Matrix Isolation Study of the Reaction of B2H6 with H2S: Spectroscopic Characterization of Mercaptoborane,H2BSH.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: V2O2F4 (H2O)2·H2O: A New V4+ Layer Structure Related to VOF3.

Single crystals of the title compound are prepared by hydrothermal reaction of VF₃ and H₂SeO₃ in ethylene glycol/HF (40%) in the presence of Et₂NH (autoclave, 393 K, 4 d).     

Synthesis of two new families of fluorinated compounds: 1H,1H,2H,2H-perfluoro-3,5-alkyldiynols and 1H,1H-perfluoro-2,4-alkyldiynols and their acrylates and methacrylates

The synthesis of two new families of compounds, 1H,1H,2H,2H-perfluoro-3,5-alkyldiynols and 1H,1H-perfluoro-2,4-alkyldiynols, and their acrylates and methacrylates, precursors of polymeric systems with important physical properties, is described.     

Synthesis of Diaminophosphonium Salts [Ph2(ArNH)2P]+Br− (Ar = o-MeC6H4, p-MeC6H4, p-Pr i C6H4, p-EtO2CC6H4, p-MeOC6H4)

The behavior of different anilines H₂NC₆H₄R (R = o-Me, p-Me, o-, m- and p? ⁱ Pr, p-OMe, p-CO₂Et) and 2,6-Me₂C₆H₃NH₂ towards trihalophosphoranes was studied. 2,6-Me₂C₆H₃NH₂ failed to form the diaminophosphonium salt [Ph₂PNH(2,6-Me₂C₆H₃)₂]Br, and the aminophosphine oxide Ph₂(2,6-Me₂C₆H₃NH)PO was the only isolated product. Both o- and p-toluidine gave the corresponding diaminophosphonium salts; however in the case of o-toluidine, the yield was low and a mixture with the respective aminophosphine oxide was observed. Anilines containing methoxy and ethoxycarbonyl groups in para-position form the diaminophosphonium salts in reasonable yields.     

ChemInform Abstract: Preparation and Crystal Structures of the Vanadiumphosphates VPO4. times.2 H2O (I) and V5.12(PO4)4(OH)3.36(H2O)0.64×0.84 H2O (II).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

On the interaction of Mo and Mo2 with NH3, C2H4, and C3H6

The reactivity of Mo and Mo₂ with ammonia, ethene, and propene molecules has been investigated by using Density Functional Theory. Different gradient‐corrected and hybrid exchange‐correlation functionals have been employed. Coordination modes, binding energies, geometrical structures, vibrational frequencies have been computed and compared with the available experimental counterparts. The results obtained show that the molybdenum atom is able to react with C₂H₄ and C₃H₆, and binds weakly with NH₃. The dimer Mo₂ gives a stable complexes with ammonia, ethene, and propene. For the Mo₂NH₃ complex, all the employed levels of theory give binding energies in good agreement with the experimental value, while in the case of the MoC₂H₄ system, the use of model core potentials coupled with gradient‐corrected exchange‐correlation functionals overestimates the binding energies. For MoC₃H₆, Mo₂C₂H₄, and Mo₂C₃H₆ we predict a binding energy of 14–15, 20–24, and 18–20 kcal/mol, respectively. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1557–1564, 2001     

Die Kristallstruktur des Bleicyclotetraphosphat-2-Hydrats,Pb2P4O12 · 2H2O

Crystal Structure of Lead Cyclotetraphosphate-2-Hydrate, Pb₂P₄O₁₂ · 2H₂O By heating of Pb₂P₄O₁₂ · 4 H₂O crystals at 100°C, Pb₂P₄O₁₂ · 2 H₂O is formed topotactically. The triclinic crystals are twinned on (010). Space group: P1 , unit cell: a = 8.02 ± 0.02, b = 10.58 ± 0.02, c = 7.53 ± 0.02 Å, α = 98.8 ± 0.2, β = 108.7 ± 0.2, γ = 82.6 ± 0.3°. The crystal structure was determined by Patterson and Fourier methods and refined by least-squares calculations. The structure consists of two crystallographically different P₄O₁₂^4? ring anions, point symmetry 1 , connected by Pb and hydrogen bonds. Both Pb atoms are coordinated by eight oxygen atoms. The polyhedra of either Pb are interconnected by common edges forming sheets and chains. Pb(1) is joined with four, Pb(2) with five P₄O₁₂^4? anions.