- Chloro(N,N′,N″-trimethyl-1,5,9-triazacyclododecane-κ 3N)zinc(II) hexafluorophosphate
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The preparation and crystal structure of [ZnCl(C12H27-N3)]PF6 are described. The Zn atom has a tetrahedral environment, coordinated to three N atoms of the triaza macrocyclic ligand and to one Cl- ion. The Zn - N distances are in the range 2.037 (1)-2.048 (1) A, with Zn - Cl 2.2010 (4) A.
- Alcock, Nathaniel W.,Clase, Howard J.,Siltchenko, Svetlana,Rybak-Akimova, Elena,Busch, Daryle H.
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- Method for preparing alkoxyamines from nitroxides
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The invention relates to a process for preparing alkoxyamines. This process consists in mixing, in an organic solvent, a metal salt, a ligand for the metal, a halocarbon compound ZX and a nitroxide, in keeping the reaction medium stirring at a temperature of between 20° C. and 90° C. until the nitroxide has disappeared, in recovering the organic phase, in washing it with water and then in isolating the alkoxyamine by evaporating the organic solvent under reduced pressure.
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- Coordination to RMg+ and RZn+ cations
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Addition of a second coordinating agent (coord*) to a solution of RM(coord)+A- (R = ethyl or neopentyl, M = Zn or Mg, A- = 1,2,3,4-tetraphenylcyclopentadienyl) can provide equilibrium mixtures of these compounds, coord, and RM(coord*)+A-. This exchange with RMg(coord)+ requires the addition of a small amount of R2Mg, but added R2Zn is not necessary for exchanges with RZn(coord)+. The equilibrium constants provide information about the relative abilities of different coordinating agents to coordinate to RM+ and reveal significant differences between coordination to RMg+ and RZn+. Reactions of RM(coord)+ with R′2M (R = ethyl or neopentyl for RMg(coord)+ and ethyl, isopropyl, tert-butyl, neopentyl, or p-methylphenyl for RZn(coord)+) provide equilibrium mixtures of these components, R′M(coord)+, and R2M. The equilibrium constants provide information about the effect of R on stability. An X-ray structure of p-methylphenylzinc(2,5,8,11-tetramethyl-2,5,8,11-tetraazadodecane)+ shows that just three of the N atoms are coordinated to Zn. The effects of coord, R, and metal on RM(coord)+ stability are discussed, and the abilities of coordinating agents to coordinate to RM+, to slow allylic isomerization of (CH2 double bond CMeCH2)2Zn, and to convert R2Zn to RZn(coord)+ are compared.
- Tang, Hui
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p. 4810 - 4819
(2008/10/08)
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- New Synthetic Routes to Macrocyclic Triamines
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1,5,9-Triazacyclododecane and related macrocyclic triamines can be conveniently constructed around a single carbon atom as a template; this route permits the preparation of selectively alkylated derivatives.
- Alder, Roger W.,Mowlam, Rodney W.,Vachon, David J.,Weisman, Gary R.
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p. 507 - 508
(2007/10/02)
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- Fragmentation During the Formic Acid/Formaldehyde (Eschweiler-Clarke) Methylation of Polyamines
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Eschweiler-Clarke methylations of both acyclic and cyclic polyamines can lead to methylation products of fragments of the original polyamine; thus 1,5,9,13-tetra-azatridecane yields 1,1,3,3-tetramethylpropanediamine exclusively and 1,5,9-triazacyclododecane gives 45 percent 1,5,9-trimethyl-1,5,9-triazacyclododecane and 45 percent 2,6,10-trimethyl-2,6,10-triazaundecane.
- Alder, Roger W.,Colclough, David,Mowlam, Rodney W.
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p. 7755 - 7758
(2007/10/02)
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