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1.
G. M. Maksimov R. I. Maksimovskaya O. A. Kholdeeva M. A. Fedotov V. I. Zaikovskii V. G. Vasil’ev S. S. Arzumanov 《Journal of Structural Chemistry》2009,50(4):618-627
Heteropoly acid (HPA) H8(PW11TiO39)2O·xH2O (I) is synthesized by three different ways and studied by chemical analysis, potentiometric titration, mass-spectrometry, IR,
31P, 183W, and 17O NMR spectroscopy, thermogravimetry, and transmission electron microscopy. Anion I consists of two subparticles of the Keggin structure bridged by Ti-O-Ti. The dimeric anion exists in HPA aqueous solutions
at [I] > 0.02 M. At pH > 0.6 it splits to a [PW11TiO40]5− monomer stable up to pH ∼ 6. When heated (150–400)°C, I splits into H3PW12O40 and, apparently, H3PW10Ti2O38 without phase separation. Thermolysis products are soluble and when dissolved in water turn again into I. Complete decomposition of I to oxides occurs at ∼450°C. 相似文献
2.
A novel trinuclear NiII cluster, {[Ni(H2L)(EtOH)]2(OAc)2Ni} · 2EtOH [H4L:5,5′-Dihydroxy-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol], has been synthesized and structurally characterized.
The X-ray crystal structure of the cluster reveals that two acetates coordinate to three nickel ions through Ni–O–C–O–Ni bridges
and four μ-phenoxo oxygen atoms from two [Ni(H2L)] units also coordinate to nickel ions. Around three nickel atoms are all octahedral geometries. 相似文献
3.
S. P. Khranenko P. E. Plusnin L. A. Sheludyakova Yu. V. Gerasimova I. V. Korol’kov S. V. Korenev 《Russian Journal of Coordination Chemistry》2009,35(9):681-686
Complexation between crystalline trans-[Pd(H2O)2(NO3)2] and acetylacetone was studied. The complexes Pd2(Acac)2(μ-NO3)2(I) and Pd2(Acac)2(μ-Acac)(μ-NO3)(II) were obtained and examined by elemental analysis, X-ray powder diffraction analysis, differential scanning calorimetry,
simultaneous thermal analysis, mass spectrometry, and vibrational spectroscopy. 相似文献
4.
A. L. Gushchin K. A. Kovalenko M. N. Sokolov D. Yu. Naumov E. V. Peresypkina A. V. Virovets V. P. Fedin 《Russian Chemical Bulletin》2007,56(9):1707-1711
The reactions of the oxalate complexes [M3Q7(C2O4)3]2− (M = Mo or W; Q = S or Se) with MnII, CoII, NiII, and CuII aqua and ethylenediamine complexes in aqueous and aqueous ethanolic solutions were studied. The previously unknown heterometallic
complexes [Mo3Se7(C2O4)3Ni(H2O)5]·3.5H2O (1) and K3{[Cu(en)2H2O]([Mo3S7(ox)3]2Br)}·5.5H2O (2) were synthesized. In these complexes, the oxalate clusters serve as monodentate ligands. The K(H2en)2[W3S7(C2O4)3]2Br·4H2O salt (3) was isolated from solutions containing CoII, NiII, or CuII aqua complexes and ethylenediamine. The reaction of [Mo3Se7(C2O4)3]2− with HBr produced the bromide complex [Mo3Se7Br6]2−, which was isolated as (Bu4N)2[Mo3Se7Br6] (4). Complexes 1–3 were characterized by X-ray diffraction, IR spectra, and elemental analysis. The formation of 4 was detected by electrospray mass spectrometry.
Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1645–1649, September, 2007. 相似文献
5.
Jia-xu Zhang Ze-sheng Li Jing-yao Liu Chia-chung Sun 《Theoretical chemistry accounts》2007,117(4):579-586
The radical–molecule reaction mechanism of CH2Cl with NO2 has been explored theoretically at the B3LYP/6–311G(d,p) and MC–QCISD (single-point) levels of theory. Our results indicate that the title reaction proceeds mostly through singlet
pathways, less go through triplet pathways. The initial association between CH2Cl and NO2 is found to be the carbon-to-nitrogen attack forming the adduct a H2ClCNO2 with no barrier, followed by isomerization to b
1
H2ClCONO-trans which can easily convert to b
2
H2ClCONO-cis. Subsequently, the most feasible pathway is the C–Cl and O–N bonds cleavage along with the N–Cl bond formation of b (b
1
, b
2
) leading to product P
1
CH2O + ClNO, which can further dissociate to give P
5
CH2O + Cl + NO. The second competitive pathway is the 1,3-H-shift associated with O–N bond rupture of b
1
to form P
2
CHClO + HNO. Because the intermediates and transition states involved in the above two favorable channels all lie below the
reactants, the CH2Cl+NO2 reaction is expected to be rapid, as is confirmed by experiment. The present results can lead us to understand deeply the
mechanism of the title reaction and may be helpful for further experimental investigation of the reaction. 相似文献
6.
The hydrogen-bonded structures of the CH3OH complexes with CF4, C2F2, OC, Ne, and He are designated as the starting points for geometry optimizations without and with counterpoise (CP) correction
at MP2 level of theory with the basis sets 6-31+G*, 6-31++G**, and 6-311++G**, respectively. Tight convergence criteria are
applied throughout all geometry optimizations in order to reduce the computational errors. According to the optimizations
without CP correction, a blue-shifted O–H···Y (where Y = F, O, Ne, or He) hydrogen bond exists in all these five complexes.
The magnitudes of blue shifts of ν(O–H) of the former four complexes with respect to that of CH3OH are reduced greatly when the polarization and diffuse functions of the hydrogen atoms are added (results from 6-31+G* versus
those from 6-31++G**). However, for the complexes CH3OH–CF4 and CH3OH–C2F2, our optimizations using the CP corrections did not find the hydrogen-bonded structure to be a stationary point. The energy
minimum of both the complexes corresponds to a non-hydrogen-bonded structure. 相似文献
7.
K. H. Wang M. C. Zhu L. Liu E. J. Gao D. Y. Hou G. Xin T. C. Li 《Russian Journal of Coordination Chemistry》2012,38(1):29-35
A novel Ni(II) complex, [Ni(Phen)2(H2O)2][Ni(PtcH)2] · 11H2O (Phen = 1,10-phenanthroline, PtcH = pyridine-2,4,6-tricarboxylic acid), has been synthesized and characterized by elemental
analysis, FT-IR, fluorescence spectrum, TGA, and single-crystal X-ray diffraction. The complex is assembled together via strong π...π and CH...π interactions, forming a 2D metal complex framework with hydrophilic cavities. In the crystal host,
a novel 3D water network was enveloped, which was constructed by 1D water tapes containing adamantane-type (H2O)24 water cluster. 相似文献
8.
Lan-Cui Zhang Han Xue Zai-Ming Zhu Zhi-Ming Zhang Yang-Guang Li En-Bo Wang 《Journal of Cluster Science》2010,21(4):679-689
Two new wheel-shaped tungstophosphates based on 3d-transition metals (Co(II), Ni(II)) ions decorated [P8W49O187]40− anion (TM-{P8W49}), K4Na22{[Co(H2O)2Cl][Co(H2O)3]2[Co(H2O)5]1.5 [Co(H2O)3H4P8W49O187(H2O)]}·2NaCl·41·5H2O 1 and Na30{[Ni(H2O)3]2[{Ni(H2O)3}1.5H3P8W49O187 (H2O)]}·41.5H2O 2 have been synthesized by routine synthetic reaction of hexavacant Dawson polyoxonanion [P2W12O48]14− with divalent 3d transition-metal ions in aqueous solution. The two compounds are characterized by elemental analysis, IR
spectroscopy, TG analysis, electrochemical analysis, and single-crystal X-ray diffraction. Both compounds contain a 2D layer-like
structure constructed from 1D chains of wheel-type [P8W49O187]40− anions bridged via CoO6 or NiO6 units. Cyclic voltammograms and 31P NMR analysis suggest that the polyanion [P8W49O187]40− of both compounds are stable in aqueous solution (pH = 4). 相似文献
9.
N. A. Didenko K. A. Gaivoronskaya E. I. Voit A. V. Gerasimenko V. Ya. Kavun 《Russian Journal of Inorganic Chemistry》2010,55(9):1339-1346
Crystalline magnesium hexafluorozirconate MgZrF6 · 5H2O isostructural to MnZrF6 · 5H2O, and having a chain-like structure, was synthesized and studied. According to thermogravimetry, the compound undergoes stepwise
dehydration in the temperature range of 50–420°C to give the stable phase MgZrF6 · 2H2O and the final product MgZrF6 isostructural to the cubic modification of MZrF6 (M = Cu, Fe). The vibrational spectra of the initial compound and the dehydration products are analyzed and the structures
of the compounds are considered. 相似文献
10.
Yu. Malaestean I. G. Filippova A. Ellern Yu. A. Simonov S. G. Baca 《Russian Journal of Coordination Chemistry》2008,34(5):334-338
The [M(1-MeIm)2(H2O)4](Tpht) · 4H2O complexes (where M = Ni, Co; 1-MeIm is 1-methylimidazole; H2Tpht is terephthalic acid) are synthesized and characterized by X-ray diffraction analysis. The ionic structure is built of the [M(1-MeIm)2(H2O)4]2+ cations and (Tpht)2? anions. The metal ions have a distorted octahedral coordination. The cations and anions are united by hydrogen bonding system. 相似文献
11.
K. Ramalingam R. Thiruneelakandan G. Bocelli L. Righi 《Transition Metal Chemistry》2012,37(3):265-270
The complexes trans-[Ni(4-MP)2(NCS)2]·MeCN (1) and trans-[Ni(3-MP)2(NCS)2] (2) (4-MP = tri(4-methylphenyl)phosphine, 3-MP = tri(3-methylphenyl)phosphine) were prepared and characterized by IR, UV–visible,
NMR spectra, CV, TGA and single crystal X-ray crystallography. Both the complexes have planar geometry and are diamagnetic.
The Ni–P distances in both complexes are relatively short as a result of strong back donation from nickel to phosphorus. The
phenyl rings in the 3-MP analogue (2) show increased pitching with reference to the plane formed by the ipso carbons due to increased steric effects. For complex
(2), the N–Ni–N and P–Ni–P angles are significantly lower than the almost linear N–Ni–N and N–Ni–P angles observed for both
complex (1) and trans-[Ni(PPh3)2(NCS)2]. This observation indicates that the 3-methylphosphine ligand forces complex (2) to distort towards a tetrahedral geometry. IR spectra of both complexes show strong bands around 2,090 cm−1 due to N-coordinated thiocyanate, while the electronic spectra contain d–d transitions around 452 nm. Cyclic voltammograms
show that the irreversible one-electron reduction potentials increase in the following order: trans- [Ni(PPh3)2(NCS)2] < trans- [Ni(3-MP)2(NCS)2] < trans-[Ni(4-MP)2(NCS)2], revealing the electron releasing effect of the methyl groups. The planar complexes exhibit interallogony in coordinating
solvents. 相似文献
12.
A. Ananthanarayanan A. Dixit R. K. Lenka R. D. Purohit V. K. Shrikhande G. P. Kothiyal 《Journal of Thermal Analysis and Calorimetry》2011,106(3):839-844
Lithium aluminum silicate (LAS) glasses of compositions (wt%) 10.6Li2O–71.7SiO2–7.1Al2O3–4.9K2O–3.2B2O3–1.25P2O5–1.25TiO2 were prepared by the melt quench technique. Crystallization kinetics was investigated by the method of Kissinger and Augis–Bennett
using differential thermal analysis (DTA). Based on the DTA data, glass ceramics were prepared by single-, two-, and three-step
heat treatment schedules. The interdependence of different phases formed, microstructure, thermal expansion coefficient (TEC)
and microhardness (MH) was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo-mechanical
analysis (TMA), and microhardness (MH) measurements. Crystallization kinetics revealed that Li2SiO3 is the kinetically favored phase with activation energy of 91.10 kJ/mol. An Avrami exponent of n = 3.33 indicated the dominance of bulk crystallization. Based upon the formation of phases, it was observed that the two-stage
heat treatment results in highest TEC glass ceramics. The single-step heat treatment yielded glass ceramics with the highest
MH. 相似文献
13.
One new metal – organic coordination framework formulated as [{Cu(4,4′-bipy)(CH3COO)2}·3H2O]n (1) (where 4,4′-bipy=4,4′-bipyridine) has been hydrothermally synthesised and characterised by elemental analysis, IR and electronic
spectroscopy, variable temperature magnetic moment measurement and single crystal X-ray diffraction study. Single crystal
X-ray analysis reveals that 1 is one dimensional polymeric compound in which acetate ligand shows both mono- and bidentate bonding mode, and 4,4′-bipy
acts as bridging ligand which supports the formation of infinite chains. The global feature of the χ
M
T vs. T curve in 1 is characteristic of moderate antiferromagnetic interaction and the best fit parameters from 300 down to 2 K are found as
J = −78.7 cm−1. 相似文献
14.
The solubility of MnSeO3-SeO2-H2O system was studied in the temperature region 25–300°C. The compounds of the three-component system were identified by the
Schreinemaker’s method. The phase diagram of manganese(II) selenites was drawn and the crystallization fields for the different
phases were determined. Depending on the conditions for hydrothermal synthesis, MnSeO3·H2O, MnSeO3·3/4H2O, MnSeO3·l/3H2O and MnSe2O5 were obtained. The different phases were proven and characterized by chemical, powder X-ray diffraction and thermal analyses,
as well as IR spectroscopy. The kinetics of dehydration and decomposition of MnSeO3·H2O was studied under non-isothermal heating. Based on 4 calculation procedures and 27 kinetic equations, the values of activation
energy and pre-exponential factor in Arrhenius equation were calculated for both processes. 相似文献
15.
P. N. Bourosh E. B. Koropchanu A. A. Desyantnik O. A. Bologa Zh. P. Tyurina M. V. Stratan O. A. Chiobenike Ya. Lipkovsky I. I. Bulkhak Yu. A. Simonov 《Russian Journal of Coordination Chemistry》2009,35(10):751-757
The coordination compound [Co(DH)2(PP)2][BF4]2 · 2H2O (DH− is the dimethylglyoxime residue, PP is nicotinamide) was synthesized and studied by X-ray diffraction. The equatorial plane
of the octahedral Co(III) complex contains two DH− residues combined by intramolecular hydrogen bonds O-H…O, while the apical positions are occupied by two PP molecules. A
method for the optimal use of the complex for enhancement of the biosynthesis of standard and acid-stable amylases of the
micromycete Aspergillus niger 33–19 CNMN FD 02A and lipases of the micromycete Rhizopus arrhizus Fischer CNMN FD 03L was depeloped. The introduction of the complex in a concentration of 1–5 mg/l into the culture medium of Aspergillus niger 33-19 CNMN FD 02A reduces the process cycle by 24 h. The stimulating effect of the introduction of the complex (5 mg/l) into
the culture medium of the Rhizopus arrhizus Fischer CNMN FD 03L strain is 55.5%. 相似文献
16.
Abstract
Based on the polydentate ligand 3,5-bis(3-pyridyl)-1H-1,2,4-triazole (3,3′-Hbpt), three coordination compounds [Zn(3,3′-Hbpt)(ip)]·2H2O (1), [Zn(3,3′-Hbpt)(5-NO2-ip)]·H2O (2), and [Zn(3,3′-Hbpt)2(H2pm)(H2O)2]·2H2O (3) have been hydrothermally constructed with H2ip, 5-NO2-H2ip and H4pm as auxiliary ligands (H2ip = isophthalic acid, 5-NO2-H2ip = 5-NO2-isophthalic acid, H4pm = pyromellitic acid). Structural analysis reveals that Zn(II) ions serve as four-coordinated, five-coordinated, and six-coordinated connectors in 1–3, respectively, while 3,3′-Hbpt adopts μ-Npy and Npy coordination modes in two typical conformations in these target coordination compounds. Dependently the applied ligand, compounds 1–3 exhibit either 1D channel, cage or chain structures, respectively. In addition, the luminescence properties of 1–3 have been investigated in the solid state at room temperature. 相似文献17.
R. Srikanth P. Nagi Reddy K. Bhanuprakash R. Srinivas Xiaohong Chen Frantisek Tureček 《Journal of the American Society for Mass Spectrometry》2005,16(8):1353-1366
Dissociative electron ionization of diethyl dithiophosphate (I) and O,O′-diethyl methylphosphonothioate (II) generates moderately abundant m/z 81 ions of composition [P, O, S, H2]+. From tandem mass spectrometry experiments and theoretical calculations at the B3LYP/6-31G(d,p), G2, and G2 (MP2) levels
it is concluded that the majority of the ions have the structure of HS-P-OH+ (1a
+) and it is separated by high-energy barriers from its isomers P(= S)OH2+ (1b
+), P(= O)SH2+ (1c
+), HP(= S)OH+ (1d
+), and HP(= O)SH+ (1e
+). Low-energy (metastable) ions 1a
+ dissociate via losses of H2O and H2S to yield m/z 63 (PS+) and m/z 47 (PO+) product ions, respectively. These reactions involve isomerization of 1a
+ into the stable isomers 1b
+ and 1c
+. Neutralization-reionization experiments confirm the theoretical prediction that radical 1a
· is a stable species in the gas-phase. Variable-time NR experiments indicated that only a small fraction of metastable 1a
· radicals dissociate in the 0.4–4.6 μs time window, while most dissociations occurred on a shorter time scale. RRKM calculations were performed to investigate
unimolecular dissociation kinetics of 1a
· which were found to be in agreement with the fragmentation observed in the NR spectrum. The 70-eV electron ionization of
(I) and diethyl chlorothiophosphate (III) yields m/z 97 ions, predominantly of the structure S = P(OH)2+ (2a
+). This conclusion follows from tandem mass spectrometry experiments and theoretical calculations. The calculations predict
that (2a
+) is separated by high-energy barriers from its isomers O = P(SH)OH+ (2b
+), S = P(= O)OH2+ (2c
+), and O = P(= O)SH2+ (2d
+). Neutralization-reionization experiments confirmed that 2a
· radical is a kinetically stable species on the time scale of up to 5 μs, which is in agreement with ab initio calculations. However, owing to a mismatch of Franck-Condon factors a large fraction
of 2a
· dissociates by loss of SH· yielding O=P-OH. 相似文献
18.
2CaO·3B2O3·H2O which has non-linear optical (NLO) property was synthesized under hydrothermal condition and identified by XRD, FTIR and
TG as well as by chemical analysis. The molar enthalpy of solution of 2CaO·3B2O3·H2O in HCl·54.572H2O was determined. From a combination of this result with measured enthalpies of solution of H3BO3 in HCl·54.501H2O and of CaO in (HCl+H3BO3) solution, together with the standard molar enthalpies of formation of CaO(s), H3BO3(s), and H2O(l), the standard molar enthalpy of formation of −(5733.7±5.2) kJ mol−1 of 2CaO·3B2O3·H2O was obtained. Thermodynamic properties of this compound were also calculated by a group contribution method. 相似文献
19.
Three new coordination polymers, [RE(5-Nip)(5-HNip)(H2O)2)] · 2H2O (RE = Y (I), Ho (II), and Er (III)) were synthesized by hydrothermal reactions of lanthanide nitrates with 5-nitroisophthalic
acid (H2Nip) and characterized by IR spectra, elemental analysis, and single-crystal X-ray diffraction. X-ray diffraction studies
suggest that all the two-dimensional 5-nitroisophthalic complexes crystallize in the P
space group and are isomorphic. The two-dimensional layer-like structures are constructed by the lanthanide ions bridged
by 5-Nip2− ligands, and the layers further packed into 3D complexes through hydrogen bonds and two kinds of π-π stacking interactions.
These complexes exhibit high stabilities up to 465 (1), 518 (2), and 528°C (3), respectively. According to the effective ionic
radii of eight-coordinate lanthanide, Y(III) should be arranged before Ho(III) and Er(III), and we obtain a series of lines
(except for the RE-OW bonds) in the corresponding RE-O against their ionic radii. In these complexes the yttrium complex could
be located before the other two complexes according to the position of its ionic radius, and the ionic radii become a key
factor in the formation of these complexes.
The text was submitted by the authors in English. 相似文献
20.
The structure of the [Au(Dien)Cl]2[Re4Te4(CN)12]·5H2O compound prepared in an aqueous medium by the reaction of a gold(III) complex [Au(Dien)Cl]Cl2 with a tetranuclear tetrahedral tellurocyanide cluster complex of rhenium K4[Re4Te4(CN)12]·5H2O is determined by single crystal X-ray diffraction. 相似文献