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Crystal structure of a Zn(II) coordinated to a cyclen and an ethanol.
Cyclen or 1,4,7,10-tetraazacyclododecane is a
analogue of the
. Derivatives of cyclen are larger cyclic
(ethyleneimine, –CH2CH2NH–) is always the same. Like crown ethers, cyclen compounds are capable of selectively binding . They are used as a
for instance with chemicals used in
Cyclen compounds can be synthesized by combining two separate parts by . In this procedure the terminal
(1) are activated as amine anionic nucleophiles by reaction with
to the N-tosyl
followed by proton abstraction with sodium . The
end groups in
(2) are activated as
by converting them into tosyl . The two segments are joined in
and unless the reactants are very diluted, ordinary
will take place to long linear chains and not cyclization. In the final step the tosyl groups are removed with .
High dilution conditions result in a low reaction rate penalty and this disadvantage is removed in an alternative procedure starting from
– also a bis() – followed by
and ring expansion with .
In one study
bonded through a
. This complex is able to selectively bind
in a 1:2 ratio both through the adenine part and cyclen part of the molecule as evidenced by .
Schrodt, A Neubrand, A Van Eldik, Rudi (1997). "Fixation of CO2 by Zinc(II) Chelates in Alcoholic Medium. X-ray Structures of {[Zn(cyclen)]3(μ3-CO3)}(ClO4)4 and [Zn(cyclen)EtOH](ClO4)2". Inorg. Chem. 36: . :.
Atkins, T. J.; Richman, J. E.; Oettle, W. F. (1988). . ; Coll. Vol., 6, p. 652
Reed, David P.; Weisman, Gary R. (2004). . ; Coll. Vol., 10, p. 667
Xia, Chuan-Q Tan, Xin-Yu; Chen, Shan-Y Yue, Y Yu, Xiao-Qi (2006).
(PDF). . 2: 68–76.
Such?, M.; Hudson, R. H. E. (2008). "Synthetic Strategies Toward N-Functionalized Cyclens".
2008 (29): . :.
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