共查询到20条相似文献,搜索用时 578 毫秒
1.
Olaf Baake Peter S. Hoffmann Marina L. Kosinova Andreas Klein Beatrix Pollakowski Burkhard Beckhoff Nadeshda I. Fainer Valentina A. Trunova Wolfgang Ensinger 《Analytical and bioanalytical chemistry》2010,398(2):1077-1084
Triethylamine borane (TEAB) and He, N2 or NH3 were applied as additional reaction gases in the production of BCxNy layers by low-pressure chemical vapor deposition (LPCVD). These layers were deposited on Si(100) wafers and characterized
chemically by X-ray photoelectron spectroscopy (XPS) and synchrotron radiation-based total-reflection X-ray fluorescence analysis
combined with near-edge X-ray absorption fine-structure spectroscopy (TXRF-NEXAFS). The composition of the material produced
without NH3 was found to be dominated by B–C bonds with the stoichiometric formula B2C3N. B–N bonds with the formula B2CN3 were preferred when NH3 was added. A first attempt was made to compare the results obtained by applying trimethylamine borane and TEAB as single-source
precursors. 相似文献
2.
E. A. Malinina V. V. Drozdova L. V. Goeva I. N. Polyakova N. T. Kuznetsov 《Russian Journal of Inorganic Chemistry》2007,52(6):854-858
A new binuclear cadmium(II) complex with neutral ligands, 1,2-diaminobenzene (DMB) and dimethylformamide (DMF), [Cd2(Ph(NH2)2)5(DMFA)4](B10H10)2, was synthesized and studied by IR spectroscopy and X-ray diffraction. The crystals are monoclinic, a = 26.198(3) ?, b = 12.742(3) ?, c = 21.658(3) ?, β = 119.985(10)°, Z = 8, space group C2/c. The distorted octahedral environment of Cd is formed by four nitrogen atoms of three DAB molecules and two oxygen atoms
of DMF molecules. Three independent DAB molecules perform different functions: one chelates the Cd atom, another is linked
to cadmium as a monodentate ligand, and the third one bridges two Cd atoms, thus forming the dimer. The amino groups of the
DAB molecules are involved in the N-H⋯O and N-H⋯N hydrogen bonds and in N-H⋯B and N-H⋯H-B specific interactions with the cluster
boron anion.
Original Russian Text ? E.A. Malinina, V.V. Drozdova, L.V. Goeva, I.N. Polyakova, N.T. Kuznetsov, 2007, published in Zhurnal
Neorganicheskoi Khimii, 2007, Vol. 52, No. 6, pp. 922–926. 相似文献
3.
Ana B. Gaspar M. Carmen Mu?oz Nicolás Moliner Vadim Ksenofontov Georgii Levchenko Philipp Gütlich José Antonio Real 《Monatshefte für Chemie / Chemical Monthly》2003,134(2):285-294
Summary. The monomeric compounds [Fe(abpt)2(NCX)2] (X = S (1), Se (2) and abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) have been synthesized and characterized. They crystallize in the monoclinic
P21/n space group with a = 11.637(2) ?, b = 9.8021(14) ?, c = 12.9838(12) ?, β = 101.126(14)°, and Z = 2 for 1, and a = 11.601(2) ?, b = 9.6666(14) ?, c = 12.883(2) ?, β = 101.449(10)°, and Z = 2 for 2. The unit cell contains a pair mononuclear [Fe(abpt)2(NCX)2] units related by a center of symmetry. Each iron atom, located at a molecular inversion center, is in a distorted octahedral
environment. Four of the six nitrogen atoms coordinated to the Fe(II) ion belong to the pyridine-N(1) and triazole-N(2) rings
of two abpt ligands. The remaining trans positions are occupied by two nitrogen atoms, N(3), belonging to the two pseudo-halide ligands. The magnetic susceptibility
measurements at ambient pressure have revealed that they are in the high-spin range in the 2 K–300 K temperature range. The
pressure study has revealed that compound 1 remains in high-spin as pressure is increased up to 4.4 kbar, where an incomplete thermal spin crossover appears at around
T
1/2 = 65 K. Quenching experiments at 4.4 kbar have shown that the incomplete character of the conversion is a consequence of
slow kinetics. Relatively sharp spin transition takes place at T
1/2 = 106, 152 and 179 K, as pressure attains 5.6, 8.6 and 10.5 kbar, respectively.
Corresponding author. E-mail: jose.a.real@uv.es
Received June 12, 2002; accepted July 1, 2002 相似文献
4.
5.
Andreas Gupper Asunción Fernández Christina Fernández-Ramos Ferdinand Hofer Christian Mitterer Peter Warbichler 《Monatshefte für Chemie / Chemical Monthly》2002,41(3):837-848
Superhard nanocomposite coatings of different composition in the quasi-binary system TiN–TiB2 were deposited onto stainless steel sheets by means of unbalanced DC magnetron co-sputtering using segmented TiN/TiB2 targets. The chemistry and microstructure of a TiB0.6N0.7 coating was investigated using X-ray and electron diffraction, photoelectron spectroscopy, energy-filtering transmission electron microscopy, and electron energy-loss spectrometry. High resolution elemental mapping of the elements Ti, B, N, and O with energy-filtering TEM reveals a homogeneous distribution on the nanometer scale. X-Ray and electron diffraction exhibit only TiN crystallites of nanometer size, but no information on the boron-rich phase. The near-edge fine structures of the BK and NK ionization edges in the EELS spectra of the Ti–B–N coatings were used to derive information on the phases by comparing the edges with those of reference compounds. It was found that the TiN nanocrystals occur together with TiO x particles; the grains are embedded in a strongly disordered or quasi-amorphous matrix consisting mainly of TiB2 particles and, near the steel substrate, also boron oxide (B2O3). 相似文献
6.
Roman Zaremba Ute Ch. Rodewald Rainer P?ttgen 《Monatshefte für Chemie / Chemical Monthly》2007,17(1):819-822
The isotypic indides RE
5Pt2In4 (RE = Sc, Y, La–Nd, Sm, Gd–Tm, Lu) were synthesized by arc-melting of the elements and subsequent annealing. They were investigated
via X-ray powder diffraction. Small single crystals of Gd5Pt2In4 were grown via slow cooling and the structure was refined from X-ray single crystal diffractometer data: Pbam, a = 1819.2(9), b = 803.2(3), c = 367.6(2) pm, wR
2 = 0.089, 893 F
2 values and 36 parameters. The structure is an intergrowth variant of distorted trigonal and square prismatic slabs of compositions
GdPt and GdIn. Together the platinum and indium atoms build up one-dimensional [Pt2In4] networks (292–333 pm Pt–In and 328–368 pm In–In) in an AA stacking sequence along the c axis. The gadolinium atoms fill distorted square and pentagonal prismatic cages between these networks with strong bonding
to the platinum atoms. 相似文献
7.
A new pentadentate tripodal peptide ligand N,N,N′-tri(2-pyridylmethyl)glycinamide (L) has been synthesized. The crystal structure of its nickel(II) complex, [NiL(H2O)] · 1.17ClO4 · 0.17H3O · 0.03H2O (1), has been determined by X-ray diffraction. In the complex, the deprotonated ligand L acts in a pentadentate fashion
and coordinates to the nickel(II) ion through five nitrogen atoms, while the sixth position is occupied by a water molecule.
The units of the complex are connected as a 3D honeycomb network by intermolecular hydrogen bonds. The thermodynamic properties
of the ligand L with the first-series transition metal ions Co(II), Ni(II), Cu(II) and Zn(II) have been investigated by potentiometric
titration and the results show that the order of their stability constants does not conform to the Irving–Williams serial.
The reason why the stability constants of the Cu(II) complex are unconventionally small is proposed. 相似文献
8.
Thermal conversions of chitosanium dodecahydro-<Emphasis Type="Italic">closo</Emphasis>-dodecaborate
V. I. Saldin L. N. Ignat’eva Yu. M. Nikolenko V. M. Buznik Yu. M. Mikhailov 《Russian Journal of Inorganic Chemistry》2010,55(8):1221-1227
The thermal behavior of chitosanium dodecahydro-closo-dodecaborate, (C6O4H9NH3)2B12H12, was studied by thermal analysis, X-ray diffraction, and IR and X-ray photoelectron spectroscopy. As this compound is heated
at a rate above 10–20 K/min, it ignites at a temperature of about 300°C. As the compound is heated to 1000°C at a rate below
10 K/min in an inert atmosphere, it yields a mixture of carbon and amorphous boron and/or boron carbides. The presence of
a small amount of boron oxide in the product is explained by the formation of a partially oxidized hydroborate anion at the
early stages of (C6O4H9NH3)2B12H12 decomposition via the interaction between oxygen of the chitosanium cation and the B12H122− anion. Heating the initial compound in air at a rate below 10 K/min yields carbon and boron oxide as the main products. Molten
boron oxide protects boron and/or boron carbides and boron nitride forming in small amounts in the particle bulk from oxidation. 相似文献
9.
Gigantic colloidal single crystals (2–6 mm) are formed for fluorine-containing polymer spheres (120–210 nm in diameter) in
exhaustively deionized aqueous suspensions. The spheres used are poly(tetrafluoroethylene) (PTFEA and PTFEB), copolymer of
tetrafluoroethylene and perfluorovinylether (PFA) and copolymer of tetrafluoroethylene and perfluoropropylene (PTP). The phase
diagrams of these spheres are obtained in the deionized suspensions and also in the presence of sodium chloride for PFA. The
critical sphere concentrations of crystal melting (φ
c) for these spheres are around 0.0006 in volume fraction, which are close to, but slightly larger than, those of monodispersed
polystyrene spheres (φ
c ≈ 0.00015) and colloidal silica spheres(φ
c = 0.0002–0.0004) reported previously. The crystals are largest when the sphere concentrations are a bit higher than the φ
c value and their size decreases as the sphere concentration increases. Reflection spectra are taken in sedimentation equilibrium
as a function of the height from the bottom of the suspension. The static elastic modulus is estimated to be 10.8 and 28.7 Pa
for PTFEA and PTP spheres at the sphere concentrations 0.00325 and 0.00322 in volume fraction, respectively.
Received: 27 October 1999 Accepted in revised form: 16 November 1999 相似文献
10.
Bikshandarkoil R. Srinivasan Christian Näther Sunder N. Dhuri Wolfgang Bensch 《Monatshefte für Chemie / Chemical Monthly》2006,137(4):397-411
Summary. Four new organic ammonium tetrathiotungstates (N–Me–enH2)[WS4] (1), (N,N′-dm-1,3-pnH2)[WS4] (2), (1,4-bnH2)[WS4] (3), and (mipaH)2[WS4] (4), (N–Me–enH2 = N-methylethylenediammonium, N,N′-dm-1,3-pnH2 = N,N′-dimethyl-1,3-propanediammonium, 1,4-bnH2 = 1,4-butanediammonium, and mipaH = monoisopropylammonium) were synthesized by the base promoted cation exchange reaction and characterized by elemental analysis,
infrared, Raman, UV-Vis and 1H NMR spectroscopy as well as single crystal X-ray crystallography. The structures of 1–4 consist of [WS4]2− tetrahedra which are linked to the organic ammonium cations via N–H⋯S hydrogen bonding. The strength and number of the S⋯H
interactions affect the W–S bond lengths as evidenced by distinct short and long W–S bonds. The IR spectra exhibit splitting
of the W–S vibrations, which can be attributed to the distortion of the [WS4]2− tetrahedron. From a comparative study of several known tetrathiotungstates it is observed that a difference of more than
0.033 ? between the longest and shortest W–S bonds in a tetrathiotungstate will result in the splitting of the asymmetric
stretching vibration of the W–S bond. 相似文献
11.
Bikshandarkoil R. Srinivasan Christian N?ther Sunder N. Dhuri Wolfgang Bensch 《Monatshefte für Chemie / Chemical Monthly》2006,121(2):397-411
Four new organic ammonium tetrathiotungstates (N–Me–enH2)[WS4] (1), (N,N′-dm-1,3-pnH2)[WS4] (2), (1,4-bnH2)[WS4] (3), and (mipaH)2[WS4] (4), (N–Me–enH2 = N-methylethylenediammonium, N,N′-dm-1,3-pnH2 = N,N′-dimethyl-1,3-propanediammonium, 1,4-bnH2 = 1,4-butanediammonium, and mipaH = monoisopropylammonium) were synthesized by the base promoted cation exchange reaction and characterized by elemental analysis,
infrared, Raman, UV-Vis and 1H NMR spectroscopy as well as single crystal X-ray crystallography. The structures of 1–4 consist of [WS4]2− tetrahedra which are linked to the organic ammonium cations via N–H⋯S hydrogen bonding. The strength and number of the S⋯H
interactions affect the W–S bond lengths as evidenced by distinct short and long W–S bonds. The IR spectra exhibit splitting
of the W–S vibrations, which can be attributed to the distortion of the [WS4]2− tetrahedron. From a comparative study of several known tetrathiotungstates it is observed that a difference of more than
0.033 ? between the longest and shortest W–S bonds in a tetrathiotungstate will result in the splitting of the asymmetric
stretching vibration of the W–S bond. 相似文献
12.
Rahman Hosseinzadeh Ali Sharifi Kourosh Tabar-Heydar Farshid Mohsenzadeh 《Monatshefte für Chemie / Chemical Monthly》2002,118(6):1413-1415
N,N-Dimethylhydrazones of ketones and aldehydes undergo facile cleavage to the corresponding carbonyl compounds upon exposure to microwaves in water containing a catalytic amount of PdCl2–SnCl2 in high yields. 相似文献
13.
Jan A. Claußen Gonzalo Ochoa Maritza Páez Juan Costamagna Miguel Gulppi Tebello Nyokong Fethi Bedioui José H. Zagal 《Journal of Solid State Electrochemistry》2008,12(5):473-481
We have investigated the electrocatalytic activity of several substituted and unsubstituted cobalt–phthalocyanines of substituted
tetraphenyl porphyrins and of vitamin B12, for the electro-oxidation of 2-mercaptoacetate, with the complexes pre-adsorbed on a pyrolytic graphite electrode. Several
N4-macrocyclic were used to have a wide variety of Co(II)/(I) formal potentials. The electrocatalytic activity, measured as
current at constant potential, increases with the Co(II)/(I) redox potential for porphyrins as Co–pentafluorotetraphenylporphyrin < Co–tetrasulfonatotetraphenylporphyrin < Co-2,2′,2″,2‴tetra-aminotetraphenylporphyrin
and decreases for cobalt phthalocyanines as Co-3,4-octaethylhexyloxyphthalocyanine > Co–octamethoxyphthalocyanine > Co–tetranitrophthalocyanine
Co–tetraaminophthalocyanine > Co–unsubstituted phthalocyanine > Co–tetrasulfonatophthalocyanine > Co–perfluorinated phthalocyanine.
Vitamin B12 exhibits the maximum activity. A correlation of log I (at constant potential) versus the Co(II)/(I) formal potential of the catalysts gives a volcano curve. This clearly shows
that the search for better catalysts for this reaction point to those N4-macrocyclic complexes with Co(II)/(I) formal potentials close to −0.84 V versus SCE, which correspond to an optimum situation
for the interaction of the thiol with the active site.
Dedicated to Prof. Dr. Teresa Iwasita on the occasion of her 65th birthday in recognition of her numerous contributions to
interfacial electrochemistry. 相似文献
14.
Andreas Gupper Asunción Fernández Christina Fernández-Ramos Ferdinand Hofer Christian Mitterer Peter Warbichler 《Monatshefte für Chemie / Chemical Monthly》2002,133(6):837-848
Summary. Superhard nanocomposite coatings of different composition in the quasi-binary system TiN–TiB2 were deposited onto stainless steel sheets by means of unbalanced DC magnetron co-sputtering using segmented TiN/TiB2 targets. The chemistry and microstructure of a TiB0.6N0.7 coating was investigated using X-ray and electron diffraction, photoelectron spectroscopy, energy-filtering transmission
electron microscopy, and electron energy-loss spectrometry. High resolution elemental mapping of the elements Ti, B, N, and
O with energy-filtering TEM reveals a homogeneous distribution on the nanometer scale. X-Ray and electron diffraction exhibit
only TiN crystallites of nanometer size, but no information on the boron-rich phase. The near-edge fine structures of the
BK and NK ionization edges in the EELS spectra of the Ti–B–N coatings were used to derive information on the phases by comparing the
edges with those of reference compounds. It was found that the TiN nanocrystals occur together with TiO
x
particles; the grains are embedded in a strongly disordered or quasi-amorphous matrix consisting mainly of TiB2 particles and, near the steel substrate, also boron oxide (B2O3).
Received October 4, 2001. Accepted (revised) January 10, 2002 相似文献
15.
A novel polymer-forming diimide–diacid, 5,5′-bis[4-(4-trimellitimido phenoxy)phenyl]-hexahydro-4,7-methanoindan (II), was prepared by the condensation reaction of 5,5′-bis[4-(4-aminophenoxy)phenyl]-hexahydro-4,7-methanoindan with trimellitic
anhydride. A series of novel aromatic poly(amide–imide)s (PAIs) containing polycyclic cardo groups was prepared by the direct
polycondensation of II with various aromatic diamines using phosphorylation techniques. The polymers had inherent viscosities between 0.71 and 0.96 dl/g.
The polymers were soluble in polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide, and could be cast from their DMAc solutions into transparent, flexible, and tough films, except for III
a
. These films had yield strengths of 85–114 MPa, tensile strengths of 77–102 MPa, an elongation at break of 8–17%, and initial
moduli of 2.0–2.7 GPa. Wide-angle X-ray diffraction revealed that the polymers are amorphous. The glass-transition temperatures
of the polymers were in the range 242–312 °C. All the PAIs exhibited no appreciable decomposition below 430 °C, and their
10%-weight-loss temperatures were in the range 484–507 °C in nitrogen and 494–515 °C in air.
Received: 26 January 1999 Accepted in revised form: 11 May 1999 相似文献
16.
A. R. Shaikhlislamova I. A. Stenina N. A. Zhuravlev I. V. Arkhangel’skii A. I. Rebrov A. B. Yaroslavtsev 《Russian Journal of Inorganic Chemistry》2009,54(4):500-504
Cation mobility in Li3 − 2x
Nb
x
In2 − x
(PO4)3 complex phosphates was studied by impedance spectroscopy, calorimetry, and 7Li NMR spectroscopy. A phase transition at ≈273 K is suggested for compositions containing ≈1 mol lithium per formula unit.
Original Russian Text ? A.R. Shaikhlislamova, I.A. Stenina, N.A. Zhuravlev, I.V. Arkhangel’skii, A.I. Rebrov, A.B. Yaroslavtsev,
2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 4, pp. 552–557. 相似文献
17.
The two new compounds Mn(dien)2[MoS4] (1) and Mn(dien)2[Mo2O2S6] (2) (dien = diethylenetriamine) were prepared under solvothermal conditions. Both compounds were obtained as phase-pure products. The structures consist of new [Mn(dien)2]2+ cations and isolated tetrahedral [MoS4]2− (1) or [Mo2O2S6]2− (2) anions. Between the anions and the cations, hydrogen bonding is observed. Compound 1 crystallizes in the tetragonal space group I (a = 10.219(2), c = 9.259(2) ?, Z = 2), whereas 2 crystallizes in the monoclinic space group P21/c (a = 8.703(2), b = 18.390(4), c = 14.603(3) ?, β = 103.18(3)°, Z = 4). The thermal behaviour of the thiomolybdates was investigated using difference thermoanalysis (DTA) and thermogravimetry (TG). Both compounds decompose under argon with a single endothermic signal in the DTA curve (peak maximum: 252 (1) and 242°C (2)). 相似文献
18.
S.-Y. Jeon M.-B. Choi J.-H. Hwang E. D. Wachsman Sun-Ju Song 《Journal of Solid State Electrochemistry》2012,16(2):785-793
The oxygen excess nonstoichiometry of La2NiO4 + δ
is measured as a function of temperature and oxygen partial pressure (pO2) by coulometric titration method. A positive deviation from the ideal dilution solution behavior is exhibited, and the partial
molar thermodynamic quantities of La2NiO4 + δ
are calculated from the Gibbs–Helmholtz equation for regular solution by introducing the activity coefficient of the charge
carriers. The activity coefficient of holes is successfully calculated by using the Joyce–Dixon approximation of the Fermi–Dirac
integral. The effective mass of holes (
m\texth* m_{\text{h}}^{{*}} ) is 1.27–1.29 times the rest mass (m
h), which indicate the action of band-like conduction and allow the effect of the small degree of polaron hopping to be ignored.
The activity coefficient of holes calculated against the oxygen nonstoichiometry clearly illustrates the early positive deviation
of the activity coefficient of holes from unit, leading to
g\texth · \gamma_{{{\text{h}}^{ \bullet }}} ≈ 14 at δ ≈ 0.08, which is quite close to the literature value of
g\texth · \gamma_{{{\text{h}}^{ \bullet }}} ≈ 10 at δ ≈ 0.08. All the evaluated thermodynamic quantities are in good agreement with the experimental literature values. 相似文献
19.
Abstract
The crystal structure of the 2:1 co-crystal of 1,2,5-thiadiazole-3,4-dicarboxylic acid and 4,4′-bipyridine, (C4H2N2O4S)2·C10H8N2, has been determined by X-ray diffraction at the monoclinic space group C2/c with cell parameters of a = 21.388(7) ?, b = 6.735(2) ?, c = 14.877(5) ?, β = 110.431(3)°, and Z = 4. There are one molecule of thiadiazole and a half molecule of bipyridine in the asymmetric unit. The dihedral angle between the pyridine ring planes is 40.5(3)°. Two intramolecular O–H···N [2.730(7) ?] and O–H···O [2.433(6) ?] hydrogen bonds are observed in the thiadiazole molecule. In the crystal structure, the molecules form a unique two-dimensional ladder-type network linked by intermolecular O–H···N [2.704(4) ?] hydrogen bonds and S···O [3.100(5) ?] heteroatom interactions. 相似文献20.
Quantum chemical calculations using gradient-corrected density functional theory (B3LYP) and ab initio methods at the MP2
level are reported for the geometries and bond energies of the nitrido complexes Cl2 (PH3)3ReN–X (X = BH3, BCl3, BBr3, AlH3, AlCl3, AlBr3, GaH3, GaCl3, GaBr3, O, S, Se, Te). The theoretical geometries are in excellent agreement with experimental values of related complexes which
have larger phosphine ligands. The parent nitrido complex Cl2(PH3)3ReN is a very strong Lewis base. The calculated bond dissociation energy of Cl2(PH3)3ReN–AlCl3 is D
e = 43.7 kcal/mol, which is nearly as high as the bond energy of Me3N–AlCl3. The donor-acceptor bonds of the other Cl2(PH3)3ReN–AY3 complexes are also very strong. Even stronger N–X bonds are predicted for most of the nitrido-chalcogen complexes, which
exhibit the trend X = O ≫ S > Se > Te. Analysis of the electronic structure shows that the parent compound Cl2(PH3)3ReN has a Re–N triple bond. The Re–N σ bond is clearly polarized towards nitrogen, while the two π bonds are nearly nonpolar.
The Re–N σ and π bonds become more polarized toward nitrogen when a Lewis acid or a chalcogen atom is attached. Bonding in
AY3 complexes should be described as Cl2(PH3)3ReE≡N→AY3, while the chalcogen complexes should be written with double bonds Cl2(PH3)3Re=N=X. The charge-decomposition analysis indicates that the nitrogen-chalcogen bonds of the heavier chalcogen complexes with
X = S, Se, Te can also be interpreted as donor-acceptor bonds between the nitrido complex acting as a Lewis base and the chalcogen
atom with an empty p(σ) orbital acting as a Lewis acid. The nitrido oxo complex Cl2(PH3)3 Re=N=O has a covalent N–O double bond.
Received: 27 July 1998 / Accepted: 26 October 1998 / Published online: 16 March 1999 相似文献