Development of Fe(III)-containing ether-functionalized imidazolium ionic liquids for aryl Grignard cross-coupling of alkyl halides

A series of Fe(Ⅲ)-containing imidazolium-based ionic liquids containing ether substituents,including[C3OMim][FeCl4](1,[C3OMim]=1-(2-methoxyethyl)-3-methylimidazolium),[C3OiPim][FeCl4](2,[C3OiPim]=1-isopropyl-3-(2-methoxyethyl)imidazolium),[C3OBim][FeCl4](3,[C3OBim]=1-butyl-3-(2-methoxyethyl)imidazolium),[(C3O)2im][FeCl4](4,[(C3O)2im]=1,3-bis(2-methoxyethyl)imidazolium),[C3OMim][FeBr4](5)and[(C3O)2im][FeBr4](6),were prepared and characterized by elemental analysis,Raman spectroscopy and electrospray ionization mass spectrometry.The catalytic performances of 1–6 and related Fe(III)-based catalysts in the cross-coupling of aryl Grignard reagents with alkyl halides bearing-hydrogens were studied,revealing that mono(ether)functionality improves the catalytic activity and that bis(ether)functionality improves the reusability.After simply decanting the product contained in the ethereal layer,complex 4,which containing bis(ether)-functionalized imidazolium cation,could be successfully recycled seven times.     

4-Formyl-2-（2H-benzotriazol-2-yl）-phenol： an ESIPT chromophore

In the present work, excited state intramolecular proton transfer （ESIPT） emission properties of a new benzotriazole derivative 4-formyl-2-（2H-benzotriazol-2-yl）- phenol （C1） were studied. 4-Formyl-2-（2H-benzotriazol-2- yl）-methoxy-benzene （C2）, 4-formyl-2-（2H-benzotriazol-2- yl）-phenyl acetate （C3） and 4-methyl-2-（2H-benzotriazol- 2-yl）-phenol （C4） were used as the reference molecules. ^1H NMR chemical shift of hydroxy group in C1 was located at more down field than that of C4 or p-hydroxy-benzaldehyde （C5）, respectively. C1 showed two absorption bands in the range of 260-400 nm zones in various solvents, while C2 and C3 exhibited single absorption band. The equal molar mixtures of C2/C5 or C3/C5 showed single absorption band. C2 and C3 displayed single fluorescence emission band in various solvents, while C1 exhibited dual emission bands in some strong polar solvents. Furthermore, the second emission band in these strong polar solvents showed the large Stokes shift. The results show that the second emission band of C1 was produced by ESIPT. C2 and C3 could not undergo ESIPT due to no hydroxy group. The geometry optimization calculation of enol and keto forms in the ground and excited states of C1 provided tough theoretical evidences of ESIPT.     

Synthesis and characterization of carbon-bridged bis(phenolate) lanthanum alkoxides and their catalytic behavior for the polymerization of L-lactide

Four lanthanum alkoxides stabilized by a carbon-bridged bis(phenolate) ligand were synthesized and their catalytic behavior for the ring-opening polymerization of L-lactide was explored. Reactions of [(MBMP)LaCp(THF) 2 ] (MBMP 2 = 2,2′-methylene-bis(6-tert-butyl-4-methyl phenoxo)) with HOCH 2 Ph, HOCH 2 CF 3 , HOCH(CH 3 ) 2 , and HOCH 2 CH 2 N(CH 3 ) 2 , respectively, in a 1:1 molar ratio in THF gave the dimeric lanthanum alkoxo complexes [(MBMP)Ln(μ-OR)(THF) 2 ] 2 (OR = OCH 2 Ph(1), OCH 2 CF 3 (2), OCH(CH 3 ) 2 (3), OCH 2 CH 2 N(CH 3 ) 2 (4)]. These complexes were well characterized, and the definitive molecular structure of complex 1 was determined. It was found that complexes 1 to 4 are efficient initiators for the ring-opening polymerization of L-lactide. The structure of the alkoxo groups has a significant effect on the catalytic behavior, and complex 2 can initiate L-lactide polymerization in a controlled manner.     

Synthesis and self-assembly of two 1,3-alternate thiacalix[4]arenes derivatives bearing amide groups

Two 1,3-alternate thiacalix[4]arene derivatives bearing amide groups, 1,3-alternate p-tert-butylthiacalix[4]arene tetraamide (4), and 1,3-alternate p-H-thiacalix[4]arene tetraamide (6) were prepared, and their crystal structures were determined by single-crystal X-ray diffraction method. The steric hindrances posed by tert-butyl groups play an important part in the synthesis and the self-assembly of the two compounds. Compound 6 was synthesized from the corresponding ester, which was obtained by the reaction of acid chloride with ammonia. In the crystal structure, compound 4 presents a highly symmetric molecular structure, while for compound 6, because of absence of tert-butyl groups, it presents a more flexible molecular structure.     

New terpenoids from the roots of Jatropha curcas

Two new sesquiterpenoids,(1S,2R)-dihydroxycycloax-4(15)-ene(1),14-dehydroxyl daucucarotol(2),and one new rhamnofalane diterpenoid,2-hydroxy-3-dehydroxycaniojane(3),together with two known compounds,curcusone D(4) and curcusone C(5),were isolated from the roots of Jatropha curcas.The chemical structures of these compounds were established by chemical methods and extensive 1D-and 2D-NMR spectroscopic data analyses.     

Synthesis, structure, optoelectronic properties of novel zinc Schiff-base complexes

Two novel zinc Schiff-base complexes, bis-(N-(2-hydroxybenzidene)-p-aminodimethylaniline)zinc(II) (2) and bis-(N-(2-hydroxy-1-naphthidene)-p-aminodimethylaniline)zinc(II) (4) were designed and synthesized. Both the complexes exhibit good solubility in organic solvents and excellent thermal stabilities. A single crystal of 2 was grown and its crystalline structure was determined from X-ray diffraction data. Analysis of the electronic structures of both the zinc complexes calculated by density functional theory reveals a localization of orbital. The UV-Vis absorption and photoluminescence profiles of 4 in thin film are similar to those of 2, but the emission for 4 is red-shifted compared to 2. Three-layered devices with a configuration of ITO/NPB/2/Alq 3 /LiF/Al and ITO/NPB/4/Alq 3 /LiF/Al show a yellow and red emission, respectively.     

Ionic iron（III） complex of aryloxo-linked bis（imidazolium） cations： efficient and recyclable catalyst for aryl Grignard cross-coupling of alkyl chlorides

A novel phenol-linked bis（imidazolium） salt, H3LCl2 （L = O-4-C（CH3）3-C6H2-2,6-di[CH2{C（NCHCH- NAr）}]2, Ar = 2,6-diisopropylphenyl, 1）, was designed and used to prepare an ionic iron（III） complex [H2L][FeCl4] （2）. Complex 2 was a highly efficient catalyst for aryl Grignard cross-coupling of alkyl chlorides bearing β-hydrogens. Furthermore, complex 2 was reusable and could be reused in at least eight times without significant loss in catalytic activity.     

An operator on ascent sequences

We solve two problems about ascent sequences: how to get the ascent sequence of the reflection of A with respect to its antidiagonal for a matrix A∈ Intn and its ascent sequences, and how to determine the ascent sequence of A+B for k×k matrices A∈ Intn and B∈ Intm. We give the other definition of ascent sequence and get M-sequence. For the first question, we define M-sequence of A and rewrite the ascent sequences as another form.We build the bijection between M-sequences and ascent sequences and prove that our bijection is well-defined. For the second question, we define an operation on M-sequences. On the basis of the operation and the bijections, we get the ascent sequences of the sum of two matrices.     

A new second-order Mehrotra-type predictor-corrector algorithm for SDO

In Zhang's recent works,a second-order Mehrotra-type predictor-corrector algorithm for linear optimization was extended to semidefinite optimization and derived that the algorithm for semidefinite optimization had O(n~(3/2)log(X~0)~T·S~0/ε) iteration complexity based on the NT direction as Newton search direction. In this paper, we extend the second-order Mehrotra-type predictor-corrector algorithm for linear optimization to semidefinite optimization and discuss the polynomial convergence of the algorithm by modifying the corrector direction and new iterates. It is proved that the iteration complexity is reduced to O(n~(3/2)log(X~0)~T·S~0/ε), which coincides with the currently best iteration bound of Mehrotra-type predictor-corrector algorithm for semidefinite optimization.     

Synthesis, spectra, structure and quantum chemistry study on two novel oxovanadium complexes with hydrotris （pyrazolyl） borate ligands

Vanadium is a trace element in lives. Though vana- dium was investigated in life science from 1876, the importance of vanadium in lives was not recognized until 1971[1,2]. Since bromoperoxidase and nitrogenase were found and proved that vanadium plays an …     

A wide neighborhood arc-search interior-point algorithm for convex quadratic programming

In this paper, we propose an arc-search interior-point algorithm for convex quadratic programming with a wide neighborhood of the central path, which searches the optimizers along the ellipses that approximate the entire central path. The favorable polynomial complexity bound of the algorithm is obtained, namely O(nlog(( x~0)~TS~0/ε)) which is as good as the linear programming analogue. Finally, the numerical experiments show that the proposed algorithm is efficient.     

A practical process for the synthesis of translocator protein 18kDa imidazopyridine ligand

In this article, an effective feasible method to synthesize translocator protein 18kDa （TSPO） imidazopyridine ligand 7 is discussed. A new procedure for the synthesis of the key intermediate 17 has been developed in four steps （condensation, diazo reaction, hydrolysis, amidation） from 2-aminopyridine 18. The overall yield was increased from 18% to 31.6%. One of the key steps is using activated copper powder as a catalyst in several cycles. Finally, reduction of 17 with Zn dust completed the synthesis of TSPO imidazopyridine ligand 7 in 86% yield.     

A generalized funk’s section theorem for measures

If L is a star body in R~n whose central(n-i)-slices have the same(n-i)-dimensional measure μ_(n-i)(with appropriate density)as the central(n-i)-slices of an origin-symmetric star body K,then the corresponding n-dimensional measures μ_n of K and L satisfy μ_n(K)≤μ_n(L).This extends a generalized Funk’s section theorem for volumes to that for measures.     

Identification of Markovian open system dynamics for qubit systems

We discuss the problem of identification of the dynamical generators for open two-level quantum systems in a Markovian environment.Based on Bloch sphere representation,the identification problem is converted to the estimation of a 3-dimensional real process matrix A and an inhomogeneous term c.The parameter identifiability and sufficient conditions for completely identification of A and c are obtained.Further discussion shows that the obtained sufficient conditions are not always necessary.The approach can be generalized to finite-level open quantum systems in an arbitary Markovian environment.     

Super-Edge-Connectivity of G(k,d,s)(s≥k/2)

A graph G is super-edge-connected,for short super-λ,if every minimum edge-cut consists of edges adjacent to a vertex of minimum degree.Alphabet overlap graph G(k,d,s)is undirected,simple graph with vertex set V={v|v=1()kv…v;vi∈{1,2,…,d},i=1,…,k}.Two vertices u=(u1…uk)and v=(v1…vk)are adjacent if and only if us+i=vi or vs+i=ui(i=1,…,k-s).In particular G(k,d,1)is just an undirected de Bruijn graph.In this paper,we show that the diameter of G(k,d,s)is k s,the girth is 3.Finally,we prove that G(k,d,s)(s≥k/2)is super-λ.     

Calibration of the U 37 K′ index of long-chain alkenones with the in-situ water temperature in Lake Qinghai in the Tibetan Plateau

Long-chain alkenones (LCAs) can potentially be used as indicators to understand past variations in lacustrine environments.Previous research has suggested that the relationship between the temperature and the unsaturation index of LCAs should be calibrated individually,because of the possible variations in the alkenone-producing algal species in the lacustrine environment.In this work,we have calibrated U37K’ of water filter samples against the in-situ water temperature in Lake Qinghai,Tibetan Plateau.There are significant relationships between U37K’ and the water temperature,a non-linear relationship was derived.Because the U37K’ values did not respond sensitively at lower temperatures,we suggested that a quadratic regression (U37K’ =0.0011×T2-0.0201×T+0.1959,n=15,r2=0.74) was appropriate than linear regression to represent the relationship between the in-situ temperatures and U37K’.Meanwhile,the U37K correlation relationship was not more significant than U37K’ index in our study.Because of the C37:4 effects by salinity change,we suggest U37K is not as robust as the U37K’ index as a temperature proxy,at least for the salt lake in the Tibetan Plateau.The calibration of the U37K’ index in this work has provided a new understanding of historic climatic changes in the Tibetan Plateau.     

Reductive immobilization of perrhenate in soil and groundwater using starch-stabilized ZVI nanoparticles

Perrhenate(ReO4-) was used as nonradioactive surrogate for the radionuclide pertechnetate(99TcO-4) to investigate the potential of using starch-stabilized zero valent iron(ZVI) nanoparticles for reductive immobilization of pertechnetate in soil and groundwater.Batch kinetic tests indicated that the starch-stabilized ZVI nanoparticles were able to reductively remove ～96% of perrhenate(10 mg/L) from water within 8 h.XRD analyses confirmed that ReO 2 was the reduction product.A pseudo-first-order kinetic model was able to interpret the kinetic data,which gave a pseudo first order rate constant(kobs) value of 0.43h-1 at pH 6.9 and room temperature(25℃).Increasing solution pH up to 8 progressively increased the reaction rate.However,highly alkaline pH(10) resulted in much inhibited reaction rate.Consequently,the optimal pH range was identified to be from 7 to 8.Increasing solution temperature from 15 to 45℃ increased k obs from 0.38 to 0.53 h-1.The classical Arrhenius equation was able to interpret the temperature effect,which gave a low activation energy value of 7.61 kJ/mol.When the ReO-4-loaded loess was treated with the stabilized nanoparticles suspension([Fe]=560 mg/L),the water leachable ReO-4 was reduced by 57% and nearly all eluted Re was in the form of ReO2.This finding indicates that starch-stabilized ZVI nanoparticles are promising for facilitating in situ immobilization of ReO-4 in soil and groundwater.     

Ranks of repeated-root constacyclic code

By the discussion of division in \(F_{^{^{^{_2 m} } } } \left[ u \right]/\left\langle {u^4 } \right\rangle \), the minimal spanning set and the rank of a (1 + u + u ²) - constacyclic code with an arbitrary length N = 2 ^e n over \(\Phi \) are determined based on the factorization of (x ⁿ - 1) over \({F_{{2^m}}}\).     

Vertex disjoint cycles in intersection graphs of bases of matroids

The intersection graph of bases of a matroid M=(E, B) is a graph G=G~I(M) with vertex set V(G) and edge set E(G) such that V(G)=B(M) and E(G)={BB′:|B∩B′|≠0, B, B′∈B(M), where the same notation is used for the vertices of G and the bases of M. Suppose that|V(G~I(M))| =n and k_1+k_2+…+k_p=n, where k_i is an integer, i=1, 2,…, p. In this paper, we prove that there is a partition of V(G~I(M)) into p parts V_1 , V_2,…, V_p such that |V_i| =k_i and the subgraph H_i induced by V_i contains a k_i-cycle when k_i ≥3, H_i is isomorphic to K_2 when k_i =2 and H_i is a single point when k_i =1.     

The periodic solution for a kind odd order delay differential equation

In this paper, we use the coincidence degree theory to research the odd order delay differential equation a(t)χ(2n+1)(t)+b(t)χ(t)+g(t,-τ(t)))=p(t), and we obtain the sufficient conditions for the existence of periodic solutions, which improves and generalizes some related results in the literatures.