
%0 Journal Article
%A Buckingham, David A. 
%A Jackson, W. Gregory 
%A Marzilli, Patricia A. 
%A Sargeson, Alan M. 
%T The Synthesis, Stereochemistry and Properties of Linear and Branched Chain Tetraethylenepentaamine Cobalt(<emph type="6">III</emph>) Complexes
%J Australian Journal of Chemistry
%D 1999/04/16
%V 52
%N 3
%P 185-204
%K 
%R https://doi.org/10.1071/C98075
%U https://www.publish.csiro.au/paper/C98075 
%X Described are the syntheses, isolation and resolution of many diastereoisomers of pentaaminecobalt(III) complexes obtained from commercial-grade tetraethylenepentaamine. They contain both linear (tetraen; 3,6,9-triazaundecane-1,11-diamine) and branched chain (trenen; 3-(2-aminoethyl)-3,6-diazaoctane-1,8- diamine) isomers of C8H23N5 and are free of the many other amines present in the original (crude) pentaamine mixture. A dimeric bridging peroxocobalt(III) complex &#91;Co2(C8H23N5)2O2&#93; (ClO4)4 has been isolated and converted into a mixture of s-&#91;Co(trenen)X&#93;n+ and &#945;-anti &#946;-, &#945;-syn &#946;- and &#945;-&#945;-&#91;Co(tetraen)X&#93;2+ complexes (X = Cl&#175;, Br&#175;, N3&#175;), and the various isomers have been separated by a combination of fractional crystallization and ion-exchange chromatography. In addition, some X = NO3&#175; and OH2 derivatives have been made by a kinetic route, including the unstable &#945;-syn &#946; isomers. Many of the complexes have been resolved into their enantiomers, and visible, o.r.d. and c.d. spectra are reported. An X-ray crystallographic analysis of a prototype of each of the four isomeric complexes (X = Cl&#175; or N3&#175;) has been determined previously, thereby establishing the identity of many related complexes. Stereoretentive reactions are used to correlate these related isomers, and 13 C and 1 H n.m.r. spectra are reported. The pure trenen and tetraen ligands have been recovered from the CoIII complexes and can be distinguished by 13 C n.m.r. spectroscopy 
