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A highly stable and easy to synthesize aluminium complex bearing a flexible N 2 O 2 -donor salabza ligand ( N , N ′-bis(salicylene)-2-aminobenzylamine) in combination with tetrabutylammonium bromide forms an active binary catalytic system for the cycloaddition of CO 2 to epoxides (TOFs 120–3434 h ?1 ) under mild conditions (10 bar, 80 °C) and low catalyst loadings (0.05–0.2 mol%). Kinetic experiments have shown that the cycloaddition of CO 2 to styrene oxide catalyzed by 1 /TBAB is first order in 1 , TBAB, CO 2 and epoxide. A reaction mechanism is proposed based on these observations. Fe( III ) and Co( III ) related complexes are less active catalysts for this reaction.

The strongly hydrogen bonded species (CH 3 ) 2 SO?H 3 O + formed in concentrated hydrochloric acid displays a new low energy feature in its sulfur K-edge X-ray absorption near edge structure (XANES) spectrum . Density Functional Theory-Transition Potential (DFT-TP) calculations reveal that the strong hydrogen bonding decreases the energy of the transition S(1s) → LUMO, which has antibonding σ*(S–O) character, with about 0.8 eV. Normal coordinate force field analyses of the vibrational spectra show that the SO stretching force constant decreases from 4.72 N cm ?1 in neat liquid dimethyl sulfoxide to 3.73 N cm ?1 for the hydrogen bonded (CH 3 ) 2 SO?H 3 O + species. The effects of sulfur coordination on the ambidentate dimethyl sulfoxide molecule were investigated for the trans -Pd((CH 3 ) 2 SO) 2 Cl 2 , trans -Pd((CD 3 ) 2 SO) 2 Cl 2 and cis -Pt((CH 3 ) 2 SO) 2 Cl 2 complexes with square planar coordination of the chlorine and sulfur atoms. The XANES spectra again showed shifts toward low energy for the transition S(1 s) → LUMO, now with antibonding σ*(M–Cl, M–S) character, with a larger shift for M = Pt than Pd. DFT-TP calculations indicated that the differences between the XANES spectra of the geometrical cis and trans isomers of the M((CH 3 ) 2 SO) 2 Cl 2 complexes are expected to be too small to allow experimental distinction. The vibrational spectra of the palladium(II) and platinum(II) complexes were recorded and complete assignments of the fundamentals were achieved. Even though the M–S bond distances are quite similar the high covalency especially of the Pt–S bonds induces significant increases in the S–O stretching force constants, 6.79 and 7.18 N cm ?1 , respectively.

Trinuclear {μ-[3,5-(CF 3 ) 2 Pz]Cu} 3 reacts with acetylene to produce the 2?:?1 copper( I ) acetylene complex, Cu 4 (μ-[3,5-(CF 3 ) 2 Pz]) 4 (μ-HC CH) 2 . Related Cu 4 (μ-[4-Br-3,5-(CF 3 ) 2 Pz]) 4 (μ-HC CH) 2 and Cu 4 (μ-[4-Cl-3,5-(CF 3 ) 2 Pz]) 4 (μ-HC CH) 2 have also been isolated using the corresponding copper( I ) pyrazolate and acetylene. The 1?:?1 adducts Cu 2 (μ-[3,5-(CF 3 ) 2 Pz]) 2 (HC CH) 2 and Cu 2 (μ-[4-Br-3,5-(CF 3 ) 2 Pz]) 2 (HC CH) 2 are significantly less stable to the acetylene loss and can be observed in solution at low temperatures under excess acetylene. The X-ray crystal structures of 2?:?1 and 1?:?1 complexes, Cu 4 (μ-[3,5-(CF 3 ) 2 Pz]) 4 (μ-HC CH) 2 and Cu 2 (μ-[4-Br-3,5-(CF 3 ) 2 Pz]) 2 (HC CH) 2 are reported. Raman data show a reduction in C C stretching frequency by about ～340 and ～163 cm ?1 in the 2?:?1 and 1?:?1 Cu( I )/acetylene complexes, respectively, from that of the free acetylene. Copper( I ) pyrazolate complexes of the terminal alkynes, phenylacetylene, 1,8-nonadiyne, and 1,7-octadiyne are also reported. They form adducts involving one copper atom on each alkyne moiety. The {μ-[3,5-(CF 3 ) 2 Pz]Cu} 3 is also a very versatile and competent catalyst for alkyne transformations as evident from its ability to catalyze the alkyne C(sp)–H bond carboxylation chemistry with CO 2 , azide–alkyne cycloadditions leading to 1,2,3-triazoles including the use of acetylene itself as a substrate, and thiol addition to phenylacetylene affording vinyl sulfides.

The pursuit of optical temperature sensing with high thermal sensitivity to discriminate small temperature changes without contact with the subject possesses a crucial technological and scientific significance. Ratiometric temperature detection based on transition metals and lanthanides emerges as a promising strategy to achieve the purpose due to the dopants’ distinct thermal quenching rates. In this work, a new CaGdAlO 4 :Mn 4+ ,Tb 3+ luminescent thermometer was developed. The combination of the highly-thermal-sensitive red emission from Mn 4+ ions with the thermally-robust green emission from Tb 3+ ions renders the thermometer with a maximum relative thermal sensitivity of 2.3% K ?1 at 398 K. The well-separated red and green channels in digital images enable further evaluation of thermal sensitivity. The estimated thermal sensitivity is 2.23% K ?1 at 398 K from the pixel intensity ratio of red and green channels.

δ-BiB 3 O 6 shows a comparable nonlinear optical performance with the famous α-BiB 3 O 6 . It can be prepared either by a high temperature-high pressure method or by a sol–gel method associated with RE 3+ -doping (RE = La, Ce, Pr, and Nd). A direct solid state reaction at 700 °C stabilized 20 atom% La 3+ doped δ-BiB 3 O 6 compared to the previously reported record (15 atom%) in the literature. La 3+ doping would not only expand the thermodynamically stable region, which is critical for the synthesis, but also hasten the crystallization process. Moreover, Eu 3+ , a smaller RE cation, was also doped for the first time at a high doping level (7 atom%) simply by a seed-assisted solid state reaction, which apparently provides additional functionality and will prompt further efforts on single crystal growth of RE 3+ -doped δ-BiB 3 O 6 under ambient pressure. The combined powder X-ray diffraction and transmission electron microscopy analysis underpinned the phase purity and doping homogeneity of cation doped bismuth borates. UV-excited red luminescence was observed for δ-Bi 0.93 Eu 0.07 B 3 O 6 .

In continuation of the structure-activity study about 4-substituted chlorido[ N , N ′-disalicylidene-1,2-phenylenediamine]iron( III ) complexes as necroptosis and ferroptosis inducers, we introduced a 4-COOH group at the 1,2-phenylenediamine moiety of the lead ([Fe( III )salopheneCl]) and derived the resulting complex 15 to the respective ethyl, propyl, or butyl amides ( 16–18 ) and esters ( 19–21 ). The compounds 16–21 exerted concentration-dependent antiproliferative and antimetabolic effects against HL-60 cells. The esters were more active than the analogous amides. Elongation of the alkyl chain enhanced the activity of the amides, while that of the esters decreased. The complexes 16–21 induced necroptosis and/or ferroptosis but not apoptosis. Studies on protein binding and uptake into HL-60 cells indicated that the complexes mainly accumulated by passive transport. The high binding tendency of all complexes to apo-Transferrin, however, points to participation of a carrier-mediated transport into the cells, too.

A unique anionic phosphenium complex was prepared from reaction of an N-heterocyclic chlorophosphine with Collman's reagent or K[HFe(CO) 4 ]/NaH and characterized by spectral and XRD data. The complex behaves as an ambident nucleophile. Reactions with acetic acid, ClSnPh 3 , and a further equivalent of an N-heterocyclic chlorophosphine proceed via electrophilic functionalization at the metal site to yield appropriate mono- or bis-phosphenium complexes. Reaction with MeI at ?70 °C produces a P-alkylation product as the first spectroscopically detectable intermediate, which decays at a higher temperature to give a mixture of free P-methylated N-heterocyclic phosphine and its Fe(CO) 4 complex. The different reaction products were characterized by spectral and XRD data. Computational studies indicate that the NHP units in all complexes display π-acceptor behaviour but show no disposition to adopt phosphide-like character or formally oxidize the metal centre.

An anionic zeolite-like metal–organic framework (AZMOF) with a twisted partially augmented the net, known as the “Moravia” net, [(CH 3 ) 2 NH 2 ] 6 [Sr 13 (O) 3 ( BTTC ) 8 (OH) 2 (H 2 O) 16 ]· x S ( Sr-BTTC , where S represents non-coordinated solvent molecules, and BTTC is the abbreviation of benzo-(1,2;3,4;5,6)-tris-(thiophene-2′-carboxylic acid)), has been solvothermally synthesized and characterized, which possesses an anionic framework and nano-sized sodalite cage. Through cation-exchange, Sr-BTTC is capable of uptaking large organic cationic dyes including Rhodamine B (RB), Basic Red 2 (BR2), Crystal Violet (CV) and Methylene Blue (MB), amongst which the adsorption capability for RB (up to 545 mg g ?1 ), and BR2 (up to 675 mg g ?1 ) is the highest for reported absorbants to date.

We describe the synthesis of mixed-valent (Ln( II )/Ln( III )) dilanthanide complexes supported by a calix[4]pyrrole ligand. The complexes are obtained by one-electron reduction of Ln( III )/Ln( III ) complexes and are alkali-metal- and halide-free. The complexes are designed to activate small molecules by taking advantage of both the base and the one-electron reductant contained in their structure. We demonstrate a proof-of-principle concept of this mechanism by activating water and silanol.

This perspective highlights and evaluates recent key developments in the thermodynamic approach used to analyze trends in acid and base strength variation. According to this approach, acid and base strength ranking can be interpreted by using thermodynamic or thermochemical cycles. Each cycle generally consists of three independent but well-defined steps. The modus operandi described here entails the identification of the dominant step and the rationalization of its free energy/enthalpy/energy change along a selected series in terms of known structural chemical concepts. Developments in this approach are described by focusing on two related series of bases and two series of acids. In the case of the former the protonation of a series of N-heterocyclic amine bases together with their methyl-substituted analogs receives particular attention while in the case of acids, the acidic properties of aqua dications of elements in period 4 and group 2 are probed. It is illustrated how significant progress in computational chemistry and mass spectrometric techniques can be employed to compare ‘inherent’ basicity or acidity in the selected families of compounds by using simple gas-phase energy cycles. Unique, dual functions for both electronegativity (element and orbital) and charge density (for aqua cations) indicators are identified and used to evaluate these cycles. Solvent effects (in aqueous solution) are accommodated by including dehydration and hydration changes in appropriately-extended, three-step free energy cycles. It is further suggested that the dominant step in the extended thermodynamic cycle for monomeric aqua cations is the transfer of M(H 2 O) n 2+ complex hydrates from the gas-phase to bulk water. Charge density of the aqua cations again features prominently in proposed rationalizations. Finally, this article also sheds light on salient relationships that exist between empirically and quantum-chemically estimated enthalpy and entropy changes for the aforementioned transfer process.