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1.
Five multinuclear cyclotriphosphazene ligands were synthesized and tested for their cleavage activities to plasmid DNA.All of these new compounds were confirmed by MS,~1H NMR,~(31)p NMR,~(13)C NMR and IR.Preliminary studies on the cleavage of pUC 19 DNA in the presence of metal complexes were performed.The results revealed that these complexes could act as powerful catalysts under physiological conditions.The complexes 3b+Cu can effectively cleave DNA to nicked form,giving hydrolysis rate constant of 0.0...  相似文献   

2.
Four iron complexes {[PhN(CH2)2NH(SiMe3)]4FeLi · Et2O ( 1 ), [PhN(CH2)3NSiMe3]2FeLi(Et2O) ( 2 ), [PhN(CH2)2NCH(Ph)NSiMe3]2FeLi(Et2O)2 ( 3 ), and [PhN(CH2)3NCH(Ph)NSiMe3]2FeLi(Et2O)2 ( 4 )} with polydentate nitrogen ligands were synthesized and structurally characterized by X‐ray crystallography. The X‐ray structures of complexes 1 – 4 show that they crystallize in three different systems. The magnetic properties of 1 – 4 were investigated. The magnetization trends of magnetic field intensity show the curves of Type‐S, illustrating those complexes 1 – 4 are superparamagnetic.  相似文献   

3.
Proteins containing dinuclear Cu (II), Zn (II) centers play paramount roles in biology1. As mimetic of metal-dependent esterase, dinuclear Cu (II) and Zn (II) complexes have received a great deal of attentions2~6. They are of interest in the field of biomimetic chemistry to provide an improved understanding of the function of the biological sites and as potential catalysts for substrate oxidations. Schiff base type polydentate ligands which contain centeral hydroxyl group have been wid…  相似文献   

4.
This review will describe the ongoing efforts being made to incorporate organometallic fragments into the framework of dendrimers. While purely dendritic organic molecules are well known and well studied, species incorporating organometallic moieties potentially offer many benefits that are not available to only organic containing dendrimers. For example, catalytic or redox active organometallic functions can be included in the dendritic framework and impart these characteristics onto the dendrimer. This report will give an overview of the latest developments in this field by highlighting selected examples that detail novel synthetic strategies or dendrimer construction methodologies, interesting practical applications or address specific problems associated with organometallic dendrimers.  相似文献   

5.
A review of the methods available for the preparation of monodentate P(III) compounds containing fluoroalkenyl, fluoroalkynyl and fluoroalkyl groups is given. The synthesis, properties and coordination chemistry of some fluoroalkenyl- and fluoroalkynyl-containing phosphines derived from HFC-134a (CF3CH2F) and HFC-245fa (CF3CH2CH2F) is summarised. The development of the reaction between trimethylsilyl-containing phosphines and RfI which provides a general method by which bulky fluoroalkyl groups, such as i-C3F7, t-C4F9, c-C6F11, can be readily introduced into phosphorus(III) centres is reported. Together these methods provide a way of generating P(III) systems of the type R3−nP(Rf)n capable of possessing a wide range of steric and electronic properties.  相似文献   

6.
The reactions of Cd(NO3)2·4H2O with NH4SCN and 2,4‐dpa (2,4‐dpa = 2,4‐dipyridineamine) in CH3OH afforded the one‐dimensional coordination polymer [Cd(NCS)2(2,4‐dpa)2]n, 1 , while reaction of Cd(NO3)2·4H2O with NH4SCN and PmPa (PmPa = 2‐(1‐piperazinyl)pyrimidine) in CH3OH gave complex of the type [Cd(NCS)2(PmPa)2]n, 2. Each of the 2,4‐dpa ligand in complex 1 is coordinated to the Cd2+ metal center through pyridyl nitrogen atoms to form the one‐dimensional chain structures. The distorted {CdN4S2} octahedral coordination geometry around Cd2+ center is completed by pairs of bidentate thiocyanato ligands. Complex 2 has the 1‐D arrangement constructed through one‐dimensional double μ(N,S) end‐to‐end bridging thiocyanato groups bridged Cd(II) chains interconnected through PmPa ligands.  相似文献   

7.
We report a practical in situ quench (ISQ) procedure involving the generation of chiral secondary alkyllithiums from secondary alkyl iodides (including functionalized iodides bearing an ester or a nitrile) in the presence of various electrophiles such as aldehydes, ketones, Weinreb amides, isocyanates, sulfides, or boronates. This ISQ-reaction allowed the preparation of a broad range of optically enriched ketones, alcohols, amides, sulfides and boronic acid esters in typically 90–98 % ee. Remarkably, these reactions were performed at −78 °C or −40 °C in batch. A continuous flow set-up permitted reaction temperatures between −20 °C and 0 °C and allowed a scale-up up to a 40-fold without further optimization.  相似文献   

8.
A new family of non-symmetrical disubstituted dibenzophospholes possessing different steric and electronic effects have been synthesized and characterized. Their preliminary evaluation in rhodium-catalyzed hydroformylation reactions is presented.  相似文献   

9.
This review provides an overview of the synthetic pathways, structures, and reactivity of various nickel(IV) complexes. The complexes are classified according to the various ligand types including sulfur, oxygen, nitrogen, and phosphorus donors. The main emphasis is on different ligand systems which stabilize Ni in higher oxidation state in the solid state and solution. The structural aspects of the complexes are briefly discussed. The possible applications of these nickel(IV) complexes are reviewed and future prospects are also highlighted.  相似文献   

10.
An improved technique for the preparation of ferrocenecarboxaldehyde and two new methods for the synthesis of ferrocenemonocarboxylic acid from the aldehyde or from acetyl ferrocene are described. Using the aldehyde or the monocarboxylic acid as starting materials, some important ferrocene key intermediates were prepared: monochlorocarbonyl ferrocene, alkali metal and ammonium ferrocenoates, ferrocene carboxyaldehyde diethylacetal, ferrocenecarboxamide, et …, as well as a new ferrocene derivative: piperazinium diferrocenoate.  相似文献   

11.
The synthesis of a range of new phosphine-containing polydentate ligands has been achieved by addition of sulfur and nitrogen nucleophiles to dimethylvinylphosphine sulfide, followed by reduction of the resulting phosphine sulfides with lithium aluminium hydride.  相似文献   

12.
The design of metal–organic frameworks (MOFs) having large pore sizes and volumes often requires the use of complex organic ligands, currently synthesized using costly and time-consuming palladium-catalyzed coupling chemistry. Thus, in the present work, a new strategy for ligand design is reported, where piperazine and dihydrophenazine units are used as substitutes for benzene rings, which are the basic building block of most MOF ligands. This chemistry, which is based on simple, nucleophilic aromatic substitution (SNAr) reactions, is used for the transition metal catalyst-free construction of 21 new, carboxylate-based ligands with varying sizes, shapes, and denticity and 15 linear di- and tetra-nitriles. Moreover, to demonstrate the utility of the ligands as building blocks, 16 new structurally diverse MOFs having surface areas up to 3100 m2 g−1 were also synthesized.  相似文献   

13.
Two series of new organolanthanide(II) complexes with tetrahydro-2H-pyranyl- or N-piperidineethyl-functionalized fluorenyl ligands were synthesized via one-electron reductive elimination reaction. Treatments of [(Me3Si)2N]3LnIII(μ-Cl)Li(THF)3 with 2 equiv. of C5H9OCH2C13H9 (1) or C5H10NCH2CH2C13H9 (2), respectively, in toluene at about 80 °C produced, after workup, the corresponding organolanthanide(II) complexes with formula [η51-C5H9OCH2C13H8]2LnII (Ln = Yb (3), Ln = Eu (4)) and [η51-C5H10NCH2CH2C13H8]2LnII (Ln = Yb (5), Ln = Eu (6)) in good yields. All the compounds were fully characterized by spectroscopic methods and elemental analyses. The structures of complexes 3, 4, and 6 were additionally determined by single-crystal X-ray analyses. It represents the first example of solvent-free organolanthanide(II) complexes with fluorenyl ligands. The catalytic properties of the organolanthanide(II) complexes on the polymerization of ε-caprolactone and methyl methacrylate have been studied. The temperatures, solvents and coordination effects on the catalytic activities of the complexes were examined.  相似文献   

14.
The novel P-chirogenic anisylphenylMOP derivatives (R,R) and (R,S)-2-(anisylphenylphosphino)-2′-methoxy-1,1′-binaphthyl (10a and b) have been synthesized and their corresponding oxides characterised by X-ray crystallography. The results of a parallel screening regimen with various reducing agents highlight the sensitivity of the tertiary phosphine oxides to epimerisation and, interestingly, reveal that the PO, O-CH3 and P-C6H5 bonds can all be cleaved selectively depending on the reducing agents employed. An alternative synthesis was provided by direct coupling of the secondary phosphine with (R)-methoxytriflate 4, which led to the isolation of the optically pure P-chirogenic phosphines via their borane adducts. A brief study of the coordination chemistry of 10a with different rhodium precursors, relevant to the catalytic asymmetric addition of boronic acids to aldehydes is also reported.  相似文献   

15.
Reactions of 1,4-dibromo-2,5-difluorobenzene with two equivalents of lithium diisopropylamide at low temperature (T < −90 °C) followed by a quench with a slight excess of ClPPh2 afford 1,4-dibromo-2,5-bis(diphenylphosphino)-3,6-difluorobenzene (1) in good yields. Reacting 1 with two equivalents of BuLi followed by a quench with a slight excess of ClPR2 yield novel 1,2,4,5-tetrakis(phosphino)-3,6-difluorobenzenes 1,4-(PPh2)2-2,5-(PR2)2-C6F2 (R = Ph (2a); R = iPr (2b); R = Et (2c)) in moderate yields. Compounds 1 and 2a-c were characterized by multinuclear NMR spectroscopy and elemental analyses. In addition, molecular structures of 2a-c have been determined by single crystal X-ray crystallography. Phosphorus atoms of PPh2/PR2 substituents in 2a-c are displaced from the plane of the central phenyl ring due to steric interactions with neighboring groups.  相似文献   

16.
《Tetrahedron letters》2004,45(37):6937-6939
The synthesis of methyl bis(azol-1-yl)propionates is reported for the first time. These bridge-functionalized bis(azol-1-yl)methanes are prepared by a double Michael addition of azoles to methyl propiolate, representing a new methodology for the synthesis of polydentate ligands.  相似文献   

17.
Ni(II) mononuclear dithiocarbamate complexes with bidentate P,P ligands of composition [Ni(R2dtc)(P,P)]X {R?=?pentyl (pe), benzyl (bz); dtc?=?S2CN?; P,P?=?1,2-bis(diphenylphosphino)ethane (dppe), 1,4-bis(diphenylphosphino)butane (dppb), 1,1′-bis(diphenylphosphino) ferrocene (dppf); X?=?ClO4, Cl, Br, NCS} and binuclear complexes of composition [Ni2(μ-dpph)(R2dtc)2]X2 with a P,P-bridging ligand {P,P?=?1,6-bis(diphenylphosphino)hexane (dpph); X?=?Cl, Br, NCS} have been synthesized. The complexes have been characterized by elemental and thermal analysis, IR, electronic and 31P{1H}-NMR spectroscopy, magnetochemical and conductivity measurements. Single crystal X-ray analysis of [Ni(pe2dtc)(dppf)]ClO4 confirmed a distorted square planar coordination in the NiS2P2 chromophore. For selected samples, the catalysis of graphite oxidation was studied.  相似文献   

18.
DFT methods were employed to investigate C(sp3)-N bond-formation via reductive elimination from alkylpalladium(II) amide complexes. The hemi-lability of an ortho-methoxy substituent is computed to have minimal impact on reductive elimination barriers. In general, for both anilide and phosphine substituents, their steric impact is more substantial than electronic/Hammett factors. β-Hydrogen elimination is competitive with reductive elimination while β-methyl elimination is much less favorable. For phosphine-ligated Pd(II) amide complexes, the solvent impact on reductive elimination free energy barriers is small, and overall the substituent effects on either the phosphine or anilide ligand are subtle.  相似文献   

19.
The complexes were synthesised by adding a hot solution of the appropriate substituted thiourea in MeOH (Br m complexes) or DMF (I m complexes) to a solution of TeO 2 dissolved in hot conc. HCl. The structures of the resulting four-coordinate square planar complexes, cis -[TeBr 2 {( i PrNH) 2 CS} 2 ] ( 1 ), cis -[TeBr 2 {( i BuNH) 2 CS} 2 ] ( 2 ), trans -[TeI 2 {( i PrNH) 2 CS} 2 ] ( 3 ), and trans -[TeI 2 {( i BuNH) 2 CS} 2 ] ( 4 ), were studied by means of X-ray crystallographic methods. The average Te-S bond length in 1 and 2 is 2.5364 Å. The corresponding average Te-Br bond length is 2.9639 Å, reflecting the stronger trans influences of the two thioureas as compared to that of bromide. In 3 and 4 where there is no trans influence affecting the Te-ligand bonds, the average Te-S and Te-I bond lengths are 2.6926 and 2.9761 Å respectively. Tetraalkyl- or arylsubstituted thioureas alone as well as bulky disubstituted thioureas together with I m ligands seem to favor formation of trans complexes.  相似文献   

20.
A new mixed-heterocycle ‘extended-reach’ ligand has been synthesized and used to prepare copper(II) and nickel(II) complexes. An X-ray crystal structure determination reveals that the copper complex is an M2L2 metallomacrocycle having an unusual rectangular shape with a length of over 2nm stabilized by intramolecular π-stacking.  相似文献   

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