Tetrakis ethylenes

Jonas K, Schieferstein L, Kruger C, Tsay YH (1979) Tetrakis(ethylene)irondilithium and Bis... 

Following these results with the salen complex, Bedford reported on the synthesis of a series of Fe(iii)-salen-type complexes and the use of one of them, 75 (Figure 14), for the coupling of aryl Grignard reagents with primary and secondary alkyl halides, in Et20 at 45 Fiirstner subsequently reported on the use of the tetrakis(ethylene)fer-... 

The reaction is carried out under an inert atmosphere, using standard techniques.5 A 125-mL flask equipped with a magnetic stirring bar coated with Teflon is charged with 50 mL of methanol and di-p-chloro-tetrakis(ethylene)-dirhodium(0)6 (1.16 g 3.6 mmole). Trimethyl phosphite (5.00 g,40 mmole)is added dropwise over a period of 5 minutes. Upon completion of the addition, stirring is continued for 30 minutes until all the starting material is in solution. 

Tetrachloropalladate(II) ion catalyzes the interconversion of 1- and 2-butenes in aqueous solutions containing chloride and hydronium ions. Sodium tetrachloropalladate(II) catalyzes the conversion of allylbenzene to propenyl-benzene in acetic acid solutions. Tetrakis(ethylene))Lt,/x -dichlororhodium(l) catalyzes butene isomerization in methanolic hydrogen chloride solutions . Cyclooctadienes isomerize in benzene-methanol solutions of dichlorobis-(triphenylphosphine)platinum(11) and stannous chloride. Chloroplatinic acid-stannous chloride catalyzes the isomerization of pentenes. Coordination complexes of zero-valent nickel with tris(2-biphenylyl)phosphite or triphenyl-phosphine catalyze the isomerization of cis-1,2-divinylcyclobutane to a mixture of c/5,m-l, 5-cyclooctadiene and 4-vinylcyclohexene . Detailed discussions of reaction kinetics and mechanisms appear in the papers cited. 

Tetrakis (ethylene diamine) p-amido p-hydroxo dicobalt (III) sulphate.. NH2>... 

Poly(methoxybiphenyl tetrakis(ethylene oxide) methacrylate)... 

Polymeric rotaxanes, consisting of crown ethers threaded onto a polyurethane backbone, were synthesized by allowing the crown ether to equilibrate with tetrakis(ethylene glycol) before its reaction to bis(p-isocyanato-phenyl)methane. The threading efficiency, as measured by xln, the mole ratio of the cyclics per repeat unit, increased linearly with ring size from 36- to 60-membered crown ethers. Up to 63% by mass of the macrocycle was incorporated. The physical properties of the polyrotaxanes differ from those... 

Finally, Fiirstner showed that the low-valent tetrakis(ethylene) ferrate complex [Li(tmeda)]2[Fe(C2H4)4] is an excellent catalyst for the cross-coupling reaction between alkyl halides and aryl Grignard reagents (Scheme 4.83) [194c]. 

Fluorinated organosilicon compounds may be prepared from readUy available fluorohalocarbons by using phosphorous amides [84, 85, 86] or tetrakis(dimeth-ylamino)ethylene [57] for the generation of the fluoroorganic nucleophiles (equations 61-69). 

CHfrSiCH , and -CH2OCH3. Tetrakis-component catalyst for ethylene polymerization after activation by exposure to light. 

This dye fluoresces after binding Pb+2 and Ca+2 lead is considered an interferant to the determination of calcium by this approach. However, by complexing the divalent lead ion with the heavy metal chelator TPEN (N,N,N ,N -tetrakis(2-pyridylmethyl)ethylene-diamine) prior to the addition of the fluo-3, the fluorescent... 

Fig. 21. The N2S4 ligand diaminotetrathiol N,N,N, N -tetrakis-(2-mercaptoethyl)ethylene-diamme used to label antibodies...

The inherent chemistry above is not altered by substituting the phenyl rings of the ketone or pinacol with methyl groups. The ketone 4,4 -dimethylbenzophenone, as well as the pinacol 1,2,2-tetrakis-(4-methylphenyl)ethane-l,2-diol (TBP) react with U giving tetrakis-(4-methylphenyl)ethylene and l,l, ,2-tetrakis(4-methylphenyl)ethane. A lsl mixture of benzophenone and 4,4-dimethylbenzophenone gives the six expected coupling products. 

Freeman T.F., Seitz W.R., Oxygen probe based on tetrakis(alkylamino)ethylene chemiluminescence. Anal. Chem. 1981 53 98. 

Table 1. Common materials used in quenched-fluorescence oxygen sensing (Ru(dpp)3(C104)2 tris(diphenylphenantroline) ruthenium(II) perchlorate PtOEPK platinum(II)-octaethyl-porphine-ketone PtPFPP platinum(II)-tetrakis(pentafluorophenyl)porphine PS.poly(styrene), PSu poly(sulfone) PSB poly(styrene-butadiene) block co-polymer PVC polyvinylchloride) APET amorphous poly(ethyleneterephthalate) PE poly(ethylene).

Me Capra in particular proposed n> that the chemiluminescence reactions of a large number of organic compounds had this concerted dioxetane decomposition step as key reaction in the production of electronically excited products, namely acridinium salts 25,26,27) indolylperoxides 28>, activated oxalic esters 29>, diphenyl carbene 30>, tetrakis-dimethylamino-ethylene 31 32>, lucigenin 33>, and substituted imidazoles 23>. 

Electrochemical reduction of the 5-(bromodifluoromethyl)-l,2,4-oxadiazole 168 in the presence of tetrakis (dimethylamino)ethylene (TDAE) generates the 5-(difluoromethyl) anion which reacts with aldehydes to give the 5-g. 

The Lewis acidity and reactivity of these alkyl aluminum cocatalysts and activators with Lewis basic polar monomers such as acrylates make them impractical components in the copolymerization of ethylene with acrylates. To address this shortcoming, Brookhart et al. developed well-defined cationic species such as that shown in Fig. 2, in which the counterion (not illustrated) was the now-ubiquitous fluorinated arylborate family [34] such as tetrakis(pentaflurophenyl)borate. At very low methyl acrylate levels the nickel catalysts gave linear copolymers but with near-zero levels of acrylate incorporation. 

In 1950, Pruett et al. synthesized tetrakis(dimethylamino)ethylene, a clear, slightly yellow and mobile liquid. The authors observed a prolonged bright blue-green luminescence when the compound was exposed to oxygen or air in protic solvents [81]. The mechanism for this CL reaction, as proposed by Fletcher and Heller in 1967 [82], is shown in Figure 7. 

Figure 7 Chemiluminescent reaction of tetrakis(dimethylamino) ethylene (TDE).

This compound chemiluminesces when exposed to air or oxygen. Its CL was first demonstrated by Fletcher and Heller [47, 48] and suggested to occur via formation of a dioxetane by addition of oxygen across the ethylenic double bond. Cleavage of the dioxetane to form excited tetramethylurea results in excitation of the tetrakis (dimethylamino) ethylene, whose CL is in good agreement with the fluorescence spectrum of the parent compound. The reaction has been used for the analysis of oxygen [49, 50],... 

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