
TY  - JOUR
A1  - Bernhardt, Paul V. 
A1  - Hambley, Trevor W. 
A1  - Lawrance, Geoffrey A. 
A1  - Maeder, Marcel 
A1  - Wilkes, Eric N. 
T1  - Isomers of 1,4,8,11-Tetraazacyclotetradecane-6,13-dicarboxylate Characterized as Cobalt(<emph type="6">III</emph>) Complexes
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 2003
VL  - 56
IS  - 7
SP  - 679
EP  - 684
KW  - 
UR  - https://doi.org/10.1071/CH02246 
N2  - The major trans (1) and minor cis (2) isomers of 1,4,8,11-tetraazacyclotetradecane-6,13-dicarboxylate have been characterized as the complexes [Co(1)](ClO4) and [Co(H2)(OH2)]Cl(ClO4)&#183;H2O. The former crystallized in the C2/c space group and the latter in the P21/c space group, with cell parameters a 16.258(7), b 9.050(3), c 15.413(6) &#197;, &#946;133.29(3)&#176;, and a 9.694(4), b 16.135(1), c 12.973(5) &#197;, &#946; 93.00(2)&#176;, respectively. Their characterization completes identification of the respective trans and cis isomers for the series of c-pendant macrocycles also including 1,4,8,11-tetraazacyclotetradecane-6-amine-13-carboxylate ((3), (4)) and 1,4,8,11-tetraazacyclotetradecane-6,13-diamine ((5), (6)). The complexes show limited distortion from octahedral geometry with the strain in the presence of the coordinated c-pendant carboxylate significantly reduced compared with that for the c-pendant amine in analogues, a consequence mainly of six-membered as opposed to five-membered chelate rings involving the pendant donor. A comparison of the physical properties for the trans isomers of the octahedral complexes of (1), (3), and (5), which reflect progressively increasing strain, is presented. 
ER  -

