Isomers of 1,4,8,11-tetraazacyclotetradecane-6,13-dicarboxylate characterized as cobalt(III) complexes

Bernhardt, P. V., Hambley, T. W., Lawrance, G. A., Maeder, M. and Wilkes, E. N. (2003) Isomers of 1,4,8,11-tetraazacyclotetradecane-6,13-dicarboxylate characterized as cobalt(III) complexes. Australian Journal of Chemistry, 56 7: 679-684. doi:10.1071/CH02246

Author Bernhardt, P. V.
Hambley, T. W.
Lawrance, G. A.
Maeder, M.
Wilkes, E. N.
Title Isomers of 1,4,8,11-tetraazacyclotetradecane-6,13-dicarboxylate characterized as cobalt(III) complexes
Journal name Australian Journal of Chemistry   Check publisher's open access policy
ISSN 0004-9425
Publication date 2003
Sub-type Article (original research)
DOI 10.1071/CH02246
Volume 56
Issue 7
Start page 679
End page 684
Total pages 6
Place of publication Melbourne
Publisher CSIRO Publishing
Collection year 2003
Language eng
Subject C1
250201 Transition Metal Chemistry
780103 Chemical sciences
Abstract 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(H-2)(OH2)]Cl(ClO4).H2O. The former crystallized in the C-2/c space group and the latter in the P2(1)/c space group, with cell parameters a 16.258(7), b 9.050(3), c 15.413(6) Angstrom, beta133.29(3)degrees, and a 9.694(4), b 16.135(1), c 12.973(5) Angstrom, beta 93.00(2)degrees, 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.
Keyword Chemistry, Multidisciplinary
Arm Macrocycle 6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine
Q-Index Code C1

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Created: Wed, 15 Aug 2007, 01:52:44 EST