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1.
Extensive experimental studies of the Raman spectra of H2O and D2O ice in the lattice translational and OH (OD) stretching regions are reported for the first time at 88 K and from 0→6 kbar. An unambiguous transformation from ice Ih to ice IX has been observed, although previous studies suggest that a transition to ice II would have occurred. The ice Ih data are analysed in terms of various coefficients. 相似文献
2.
Dr. Dmitri V. Konarev Dr. Alexey A. Popov Dr. Leokadiya V. Zorina Dr. Salavat S. Khasanov Prof. Dr. Rimma N. Lyubovskaya 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(65):14858-14869
A series of compounds with Sc3N@Ih-C80 in the neutral, monomeric, and dimeric anion states have been prepared in the crystalline form and their molecular structures and optical and magnetic properties have been studied. The neutral Sc3N@Ih-C80 ⋅ 3 C6H4Cl2 ( 1 ) and (Sc3N@Ih-C80)3(TPC)2 ⋅ 5 C6H4Cl2 ( 2 , TPC=triptycene) compounds both crystallized in a high-symmetry trigonal structure. The reduction of Sc3N@Ih-C80 to the radical anion resulted in dimerization to form diamagnetic singly bonded (Sc3N@Ih-C80−)2 dimers. In contrast to {[2.2.2]cryptand(Na+)}2(Sc3N@Ih-C80−)2 ⋅ 2.5 C6H4Cl2 ( 3 ) with strongly disordered components, we synthesized new dimeric phases {[2.2.2]cryptand- (K+)}2(Sc3N@Ih-C80−)2 ⋅ 2 C6H4Cl2 ( 4 ) and {[2.2.2]cryptand- (Cs+)}2(Sc3N@Ih-C80−)2 ⋅ 2 C6H4Cl2 ( 5 ) in which only one major dimer orientation was found. The thermal stability of the (Sc3N@Ih-C80−)2 dimers was studied by EPR analysis of 3 to show their dissociation in the 400–460 K range producing monomeric Sc3N@Ih-C80.− radical anions. This species shows an EPR signal with a hyperfine splitting of 5.8 mT. The energy of the intercage C−C bond was estimated to be 234±7 kJ mol−1, the highest value among negatively charged fullerene dimers. The EPR spectra of crystalline (Bu3MeP+)3(Sc3N@Ih-C80.−)3 ⋅ C6H4Cl2 ( 6 ) are presented for the first time. The salt shows an asymmetric EPR signal, which could be fitted by three lines. Two lines were attributed to Sc3N@Ih-C80.−. Hyperfine splitting is manifested above 180 K due to the hyperfine interaction of the electron spin with the three scandium atoms (a total of 22 lines with an average splitting of 5.32 mT are observed at 220 K). Furthermore, each of the 22 lines is additionally split into six lines with an average separation of 0.82 mT. The large splitting indicates intrinsic charge and spin density transfer from the fullerene cage to the Sc3N cluster. Both the monomeric and dimeric Sc3N@Ih-C80− anions show an intrinsic shift of the IR bands attributed to the Sc3N cluster and new bands corresponding to these species appear in the NIR range of their UV/Vis/NIR spectra, which allows these anions to be distinguished from neutral species. 相似文献
3.
Single-Crystal Raman Spectra of Alums. II. Raman-active Lattice Vibrations and F.I.R. Spectra FIR and single crystal Raman spectra of seven different alums have been measured. All observed peaks are assigned to the symmetry species of the factor group Th. A part of the lattice modes could be assigned to translational and rotational motions of the sulfate (selenate) sublattice and to motions of the crystal water – [MeI(H2O)6]+ and [MeIII(H2O)6]3+ respectively. Comparison of spectra taken at 295 K and 80 K shows no frequency shifts significant for phase transition but a remarkable sharpening of especially those bands which are connected with water motions. 相似文献
4.
A parametric analysis of the Stark-split spectra of Nd3+ in frozen dilute aqueous solutions of neodymium chloride has been carried out.The similarity of the spectra of Nd3+ in frozen dilute solutions and in crystals, where the ion is nine-fold coordinated and of approximate D3h symmetry (Nd3+: LaCl3, neodymium ethylsulfate and bromate), was used to obtain initial parameter values. Simultaneous diagonalization of the free ion and crystal field hamiltonians resulted in a r.m.s. deviation σ of 11 cm?1 for 50 levels. The resulting crystal field parameters are B20 = 278 ± 19, B40 = ?201 ± 39, Bb0 = ?946 ± 55 and B66 = 663 ± 43 cm?1. Selection rules for D3h are approximately obeyed. The small value of σ, the number of levels accounted for and the fact that the final parameters are not very different from those in the crystals indicate a nine-fold coordination of approximate D3h symmetry for Nd3+ in frozen aqueous solutions. The spectra of liquid solutions show by their similarity to the spectra of frozen solutions that the same surroundings exist in the liquid. 相似文献
5.
Jan Janczak Ryszard Kubiak 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):m70-m72
Crystals of the novel title arsenic(III) phthalocyanine complex, [As(C32H16N8)]2[As4I14] or [(AsPc)+]2·[As4I14]2−, where Pc is phthalocyaninate(2−), have been obtained by the reaction of pure powdered As with phthalonitrile under a stream of iodine vapour at 493 K. The crystals are built up of separate but interacting [AsPc]+ cations and [As4I12]2− anions. The As atom of the [AsPc]+ unit is bonded to the four isoindole N atoms of the Pc macrocycle and lies 0.743 (2) Å out of the plane defined by these four N atoms. The anionic part of the complex consists of AsI3 and [AsI4]− units joined together into an [As4I14]2− anion. The arrangement of the oppositely charged moieties, [AsPc]+ and [As4I14]2−, in the crystal is determined mainly by ionic attraction and by donor–acceptor interactions between the [AsPc]+ and [As4I14]2− ions. 相似文献
6.
Andrea Spolaor Paul Vallelonga Jacopo Gabrieli Natalie Kehrwald Clara Turetta Giulio Cozzi Luisa Poto John M. C. Plane C. Boutron Carlo Barbante 《Analytical and bioanalytical chemistry》2013,405(2-3):647-654
Iodine and bromine species participate in key atmospheric reactions including the formation of cloud condensation nuclei and ozone depletion. We present a novel method coupling a high-performance liquid chromatography with ion chromatography and inductively coupled plasma mass spectrometry, which allows the determination of iodine (I) and bromine (Br) species (IO 3 ? , I?, Br?, BrO 3 ? ) at the picogram-per-gram levels presents in Antarctic ice. Chromatographic separation was achieved using an IONPAC® AS16 Analytical Column with NaOH as eluent. Detection limits for I and Br species were 5 to 9 pg g?1 with an uncertainty of less than 2.5% for all considered species. Inorganic iodine and bromine species have been determined in Antarctic ice core samples, with concentrations close to the detection limits for iodine species, and approximately 150 pg g?1 for Br?. Although iodate (IO 3 ? ) is the most abundant iodine species in the atmosphere, only the much rarer iodide (I?) species was present in Antarctic Holocene ice. Bromine was found to be present in Antarctic ice as Br?. 相似文献
7.
《Thermochimica Acta》1987,122(2):377-388
Enthalpies of solution of NaI in mixtures of water with 2-methoxyethanol and 2-ethoxyethanol (known as cellosolves) at 298.15, 308.15 and 318.15 K were measured. The enthalpies of solution in all investigated systems pass through a maximum in the water-rich region. This extremum is lower and flatter than that observed in water-unsubstituted alkanol mixtures. The enthalpic pair interaction coefficients hxy[(Na++I−)-cellosolve] were calculated and compared with appropriate data for (Na+ +I− )-alkanol pairs. The group additivity concept was used for the analysis of hxy coefficients calculated at 308.15 K, and the influence of the temperature change on the group contributions was discussed. 相似文献
8.
Hiroharu Yui Toshinori Morisaku Akira Suzuki 《Surface and interface analysis : SIA》2019,51(1):136-140
Phase transition of water confined in nanospaces with charged inner-surfaces was investigated by vibrational spectroscopy. Aerosol sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles give a series of spherical nanospaces with controlled inner-radius (Rw) with nanometer-scale precision. Successive spectroscopic measurements of the confined water with decreasing temperature revealed that the water freezes to metastable cubic ice (Ic) coexisting with super-cooled water or unstable amorphous ice at the Rw ranging from 1.0 to 2.0 nm. When Rw exceeded 2.0 nm, stable hexagonal ice (Ih) dominated. The drastic change of the dominant ice structure with the increase of 1 nm in Rw shows that the thickness of water layers affected by the inner surface can be estimated to be ~1 nm, where three or four layers of water hydrated to the surface. It is worth noting that the clear phase transition behavior of the confined water vanishes at Rw = 1.2 nm and that the gradual formation of Ic and coexistence of super-cooled water or glassy state of water are detected. The range of the effective interaction between interfacial water and the charged inner surfaces and the mechanism of the extremely slow phase transition were also discussed. 相似文献
9.
On the bases of the topological structures of the three big classes of icosahedral fullerenes: (1) Cn(Ih, n=60h2; h=1, 2,…), (2) Cn(Ih, n=20h2; h=1, 2,…), and (3) Cn(I, n=20(h2+hk+k2), h>k; h, k=1, 2,…), we derived formulas for the decomposition of their nuclear motions into irreducible representations. Hence, we obtained the infrared and Raman active modes for all of the icosahedral (Ih and I) fullerenes theoretically. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 66 : 113–117, 1998 相似文献
10.
Jan Janczak Genivaldo Júlio Perptuo 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(2):m45-m47
Crystals of the novel title arsenic(III)–phthalocyanine complex, [As(C32H16N8)]2[As2I8] or [AsPc]2[As2I8], where Pc is the phthalocyaninate(2−) macrocycle, have been obtained from the reaction of pure powdered arsenic with phthalonitrile under oxidizing conditions (iodine vapour) at 463 K. The crystals are formed by separate but interacting [AsPc]+ cations and centrosymmetric [As2I8]2− anions. The As atom of the [AsPc]+ ion is bonded to the four isoindole N atoms of the Pc macrocycle and lies 0.762 (1) Å out of their plane. The anionic part of the complex consists of two [AsI4]− units joined together into a centrosymmetric [As2I8]2− counter‐ion. The arrangement of oppositely charged moieties, viz. [AsPc]+ and [As2I8]2−, in the crystal structure is determined mainly by their ionic attractions and by π–π interactions between the aromatic phthalocyaninate(2−) macrocycles. 相似文献
11.
The pure quadrupole resonance spectrum of 17O has been measured in a 10% enriched KH2PO4 sample at 190°K at at 77°K. In the paraelectric phase all oxygen sites are chemically equivalent with e2qQ/h = 5.16 MHz and η = 0.55, whereas there are two chemically non-equivalent 17O sites in the ferroelectric phase: (e2qQ/h)1 = 5.96 MHz, ηt = 0.72 and (e2qQ/h)II = 4.85 MHz, ηII = 0.18. The results can be interpreted in terms of a double minimum type O-H—O hydrogen bond potential, where the protons above Tc rapidly fluctuate between the two equilibrium sites. In contrast with the neutron scattering results in KD2PO4, the present data show no evidence for any anomalous oxygen ferroelectric mode displacements in KH2PO4, which would not condense out below Tc. 相似文献
12.
Yajing Hu Albert Solé-Daura Dr. Yang-Rong Yao Xuechen Liu Dr. Sijie Liu Ao Yu Dr. Ping Peng Prof. Josep M. Poblet Dr. Antonio Rodríguez-Fortea Prof. Luis Echegoyen Prof. Fang-Fang Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(8):1748-1753
The chemistry of cationic forms of clusterfullerenes remain less explored than that of the corresponding neutral or anionic species. In the present work, M3N@Ih-C80 (M=Sc or Lu) cations were generated by both electrochemical and chemical oxidation methods. The as-obtained cations successfully underwent the typical Bingel–Hirsch reaction that fails with neutral Sc3N@Ih-C80. Two isomeric Sc3N@Ih-C80 cation derivatives, [5,6]-open and [6,6]-open adducts, were synthesized, and the former has never been prepared by means of a Bingel–Hirsch reaction with neutral clusterfullerenes. In the case of the Lu3N@Ih-C80 cation, however, only a [6,6]-open adduct was obtained. Density functional theory (DFT) calculations indicated that the oxidized M3N@Ih-C80 was much more reactive than the neutral compound upon addition of the diethyl bromomalonate anion. The Bingel–Hirsch reaction of M3N@Ih-C80 cations occurred by means of an unusual outer-sphere single-electron transfer (SET) process from the diethyl bromomalonate anion to the stable intermediate [M3N@C80(C2H5COO)2CBr].. Remarkably, the diethyl bromomalonate anion was found to act as both a nucleophile and an electron donor. 相似文献
13.
Tamás Szondy Maria Hegyi Vera Lengyel M. Mezei E. Kapuy 《Theoretical chemistry accounts》1974,33(3):249-261
An interpolative method for determining many-particle integrals needed in quantumchemical calculations is proposed. The basic idea is that integrals of the form ∫dr I ∫dr J?(r I ,r J )r IJ 2h (h=01,2,...,)(r I and r J are coordinates of the I-th and the J-th particle, respectively, r IJ is their distance and ?(r I ,r J ) is a charge distribution) can be easily calculated and can be used to determine integrals∫dr I ∫dr J?(r I ,r J )r IJ 2h ? 1 by interpolation (or for h = 0 by extrapolation). By making use of the identityΔ I Δ J r IJ h+4 = (h + 2) (h + 3) (h + 4) (h + 5) r IJ h (where Δ is the Laplacian operator) the extrapolation can be replaced by interpolation definitely improving the accuracy. As a probably most natural tool for interpolation the use of an auxiliary quantity called the distance function is discussed. The method can be considerably generalized (e.g. to many-particle integrals). Numerical results obtained by applying a preliminary form of the method to two-center integrals resulting from a Slater-type base are given. 相似文献
14.
C. Marhag D. Ben Hassen-Chehimi H. Said 《Journal of Thermal Analysis and Calorimetry》2006,86(1):249-254
The thermodynamic
exploitation of the solid–liquid equilibria in the MIPO3–Pb(PO3)2, MIPO3–Cu(PO3)2
and MIPO3–Ce(PO3)3
systems (with M
I=Li,
Na, K, Rb, Cs, Ag, Tl) is carried out using a semi-empirical equation of the
liquidus curves already used with success for similar binary systems.
The enthalpy of fusion is calculated for each pure polyphosphate on
the assumption that the liquid solution is ideal and only formed by MIPO3
and M(PO3)q entities (q=2 for Pb and Cu, q=3
for M=Ce). In the most binary systems,
a wide difference between the calculated values of the melting enthalpies
of these polyphosphates and the measured ones determined from the DTA curves,
was observed. This difference is probably due to the existence of some molecular
associations in the liquid phase. 相似文献
15.
Vladimir N. Afanasiev Alexandr N. Ustinov Irina Yu. Vashurina 《Journal of solution chemistry》2006,35(11):1477-1491
The isentropic compressibilities of aqueous solutions of potassium iodide, from dilute to almost saturated, were determined at 288 to 308 K based on precise measurements of the speed of ultrasound. Using proper correlations, the hydration numbers (h) were calculated as well as the molar volume and compressibility parameters of the hydrated complexes (V
h
, β
h
V
h
) of water in the hydration shell (V
1h
, β1h
V
1h), and of the cavity containing stochiometric mixtures of K+ and I−
ions (V
2h, β2h
V
2h). It is revealed that under the studied conditions, the obtained values of h and β
h
V
h are independent of temperature whereas the molar compressibility of the hydration shell β
h
V
h) is independent of concentration. The electrostatic field of the ions is shown to influence the temperature dependence of the molar volume of water in the hydration shell more substantially than a change of pressure alone influences the temperature dependence of the molar volume of pure water. 相似文献
16.
Contributions to the Chemistry of Silicon-Sulphur Compounds. XVI. Derivatives of Trialkoxysilanethiols with the Main Groups I and II Elements and Preparation of Pure Trialkoxysilanethiols Trialkoxysilanethiolates: (RO)3SiSMI and [(RO)3SiS]2MII (R 7dbond; Me, i-Pr, s-Bu, t-Bu, s-Am; MI ? Li, Na, K; MII ? Ca, Sr, Ba) were prepared in reaction of trialkoxysilanethiols and metals. Hydrates and THF solvates of these salts can also be formed. From sodium trialkoxysilanethiolates pure thiols (i-PrO)3SiSH and (s-BuO)3SiSH were prepared. 相似文献
17.
Maira R. Cerón Dr. Fang‐Fang Li Prof. Dr. Luis Echegoyen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(23):7410-7415
Based on the different oxidation potentials of endohedral fullerenes Sc3N@C80 Ih and D5h and Sc3N@C78, an efficient and useful method that avoids HPLC has been developed for their separation. Selective chemical oxidation of the Sc3N@D5h‐C80 isomer and Sc3N@C78 by using an acetylferrocenium salt [Fe(COCH3C5H4)Cp]+ followed by column chromatographic separation and reduction with CH3SNa resulted in the isolation of pure Sc3N@Ih‐C80, Sc3N@C78, and a mixture of Sc3N@D5h‐C80 and Sc3N@C68. 相似文献
18.
Gorobinskii L. V. Chernyavskii A. S. Solntsev K. A. Kuznetsov N. T. 《Russian Journal of Coordination Chemistry》2001,27(3):147-149
Reactions of iodination of monosubstituted derivatives of B12H11X2–anion (X = OC(O)CH3, OH, SCN) were studied. The reactions were shown to proceed smoothly to give B12H10(OC(O)CH3)I2–((carboxy)(iodo)[decahydro[I
h1551-20-closo]dodecaborate(2–)] anion), B12H10(OH)I2–((hydroxo)(iodo)[decahydro[I
h1551-20-closo]dodecaborate(2–)] anion), and B12H10(SCN)I2–((thiocyanato)(iodo)[decahydro[I
h1551-20-closo]dodecaborate(2–)] anion) in high yields, irrespective of the solvent used (benzene, H2O–ROH, where R = C2H5, CH2CH2CH3).1 相似文献
19.
B. K. Kasenov E. S. Mustafin M. A. Akubaeva Zh. I. Sagintaeva S. T. Edil’baeva Sh. B. Kasenova S. Zh. Davrenbekov 《Russian Journal of Inorganic Chemistry》2008,53(11):1691-1693
Ternary chromites of the composition LaMIMg(CrO3)2 (MI = Li, Na, K) were synthesized for the first time by ceramic technology from stoichiometric amounts of high purity grade La2O3; pure for analysis grade Li2CO3, Na2CO3, K2CO3, and MgCO3; and chemically pure grade Cr2O3. Using X-ray diffractometry, it has been established that compounds are crystallized in cubic and tetragonal crystal systems, and parameters of their crystal lattices have been determined. 相似文献
20.
Anhydrous neodymium(III) acetate, Nd(OAc)3 was obtained as light purple single crystals by direct oxidation of neodymium metal with malonic acid in a glass ampoule at 180 °C. It crystallizes with the monoclinic space group P21/a (no. 14) with a = 2201.7(2), b = 1850.0(1), c = 2419.0(3) pm, β = 96.127(8)°, V = 9796.8(1)·106·pm3, Z = 40 [Nd(OAc)3], R1 = 0.0430 [I0 > 2σ(I0)]. Most of the Nd3+ cations are coordinated by nine (or eight) oxygen atoms of acetate ligands which bridge these polyhedra to slightly waved layers which are stacked in the [010] direction. 相似文献