1313616-76-0Relevant academic research and scientific papers
Recognition of oxalate by a copper(II) polyaza macrobicyclic complex
Mateus, Pedro,Delgado, Rita,Brandao, Paula,Felix, Vitor
, p. 7020 - 7031 (2011)
A new polyamine macrobicyclic compound was synthesised through a [1+1] "tripod-tripod coupling" strategy and using a Schiff base condensation reaction, followed by sodium borohydride reduction. The resulting compound is a heteroditopic cage (btpN7) in which one of the head units is appropriate for the coordination of copper(II), whereas the other head is available for additional hydrogen-bonding and electrostatic interactions with substrates. The acid-base behaviour of the new compound, the stability constants of its complex with the Cu2+ ion and the association constants of the copper(II) cryptate with oxalate (oxa2-), malonate (mal 2-), succinate (suc2-), maleate (male2-) and fumarate (fum2-) were determined by potentiometry at 298.2K in aqueous solution and at an ionic strength of 0.10mol dm-3 in KNO 3. These studies revealed a clear preference of the receptor [CuHhbtpN7H2O](2+h)+ for oxa 2- over the other dicarboxylate substrates. This arises from co-operativity between metal-anion coordination and electrostatic and hydrogen-bonding interactions, in accordance with the ideal size of this dicarboxylate, which allow it to take full advantage of the potential binding sites of the receptor. A qualitative indicator-displacement study, in agreement with the potentiometric studies, demonstrated that the copper cryptate receptor can be used as a selective visual sensor for oxalate.Copyright
