Macrocyclic Ligand Design. A Large Covalently-Linked Ring System Incorporating Four Cyclam Units and its Interaction with Nickel(II), Copper(II), Zinc(II), and Cadmium(II)

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Contents Vol 62(10)

doi:10.1071/CH09312

Macrocyclic Ligand Design. A Large Covalently-Linked Ring System Incorporating Four Cyclam Units and its Interaction with Nickel(ii), Copper(ii), Zinc(ii), and Cadmium(ii)*

Ying Dong ^A, Leonard F. Lindoy ^A ^B

^A School of Chemistry, The University of Sydney, NSW 2006, Australia.
^B Corresponding author. Email: lindoy@chem.usyd.edu.au





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Australian Journal of Chemistry 62(10) 1207–1213 http://dx.doi.org/10.1071/CH09312
Submitted: 2 June 2009 Accepted: 19 June 2009 Published online: 13 October 2009

Abstract

A cyclic, tetra-linked macrocyclic species incorporating four 1,4,8,11-tetraazacyclotetradecane (cyclam) subunits has been synthesized employing Boc amine-group protecting chemistry coupled with high dilution conditions for the cyclization step. A series of 4:1 (metal:ligand (M:L)) complexes with nickel(ii), copper(ii), zinc(ii), and cadmium(ii) has been synthesized. Visible spectophotometric (including spectrophotometric titration), EPR, NMR, and electrochemical studies are reported for individual complexes and are in general accord with similar 4:1 (M:L) coordination behaviour occurring in both the solid state and in solution. The study makes available an example of a new category of large cyclic receptors whose cavity can be tuned electronically through variation of the metal centres incorporated in the cavity walls.

^* Dedicated to the memory of the late Professor A. M. Sargeson FAA, FRS – a great chemist and a true friend for more than 35 years.