375384-05-7Relevant academic research and scientific papers
A convenient and selective route to a trans-difunctionalized macrocyclic hexadentate N4O2 ligand
Luo,Rogers,Brechbiel
, p. 1105 - 1109 (2007/10/03)
The synthesis and characterization of a novel difunctionalized tetraaza macrocycle, 1,8-bis(2-hydroxybenzyl)-1,4,8,11-tetraazacyclotetradecane (abbreviated H2bcyclamb), is described. The diprotic hexadentate ligand N4O2 was conveniently synthesized in two steps by the cyclic condensation reaction of 1,4,8,11-tetraazacyclotetradecane (abbreviated cyclam) and salicylaldehyde, followed by NaBH4 reduction of the cyclic hexahydropyrimidine condensate. The difunctionalization was selective and is the first procedure of trans-difunctionalization of a tetraazamacrocycle, without generating mono-, tri-, or tetra-functionalized products, with only 1,8-difunctionalized product being isolated, and with the convenience of the functionalization occurring as a result of deprotection. The trans-arrangement of the two functional groups in H2bcyclamb was verified by X-ray crystallographic studies of the copper(II) complex [Cu(H2bcyclamb)](OAc)2·2H2O. The crystal is monoclinic, P21/c, with a = 10.0931(2), b = 13.8820(1), c = 10.8752(1) A, β = 106.332(1)°, V = 1462.26(3) A3. The structure of [Cu(H2bcyclamb)](OAc)2·2H2O also shows the metal ion in an elongated octahedral geometry.
