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The redox potentials, E 1/2 , for the reversible cobalt (III/II) redox couples of complexes of substituted macrobicyclic ligands derived from 3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane show a substantial variation with the type of substituent. The variation was subjected to a Hammett type treatment yielding a series of inductive or polar substituent constants σ E that correlate with the organic substituent constants obtained by a variety of other methods

Various (α-amino acidato) cobalt (III) complexes have been treated with SOCl 2 in DMF. Provided the amino acid side chain does not contain functionalities that react with SOCl 2 , the complex undergoes a facile oxidation to give the related α-imino acidato complex. A mechanism is proposed for these reactions

Low-spin hexadentate cobalt(II) and cobalt(III) complexes of the hexathioether cage (1,8-dimethyl-3,6,10,13,16,19-hexathiabicyclo[6.6.6]icosarie) have been synthesised, their redox and spectral properties have been investigated, and the encapsulation of the cobalt(II) ion has been established by an X-ray crystal structure determination, which shows the metal ion to be coordinated to six thioether sulphur atoms at distances ranging from 2.265(3) to 2.354(2)A.

Conversion of chelated homoserine to 2-amino-4-bromobutyrate and treatment with aqueous base leads directly to chelated 1-aminocyclopropane-1-carboxylate.

The cobalt(III) complex of the large hexathioether cage (1,9-dimethyl-3,7,11,15,18,22-hexathiabicyclo[7.7.7]tricosane) shows substantially different redox and spectral properties relative to the smaller homologous [6.6.6]icosane.

A new strategy has been developed to attach N-methylpyridine and its derivatives simply and directly to the CoIII sarcophagine cage frame (sar = 3,6,10,13,16,19-hexaazsbicyclo[6.6.6]icosane).

This paper describes aspects of the synthesis of cage complexes in relation to their prospects for use in biology. The means of attaching peptides, cholestane, paraffin tails and aromatic residues are outlined. Also, the properties of some of these molecules, especially a new class of detergents, a new polymer able to capture metal ions, the selectivity of the cages for metal ions and the DNA intercalating properties of aromatic residues attached to the cages are discussed.

The reactivity of two phosphate ester complexes designed to test the efficacy of different modes of activation of phosphate esters by metal ions has been investigated. Ethyl 4-nitrophenyl phosphate coordinated to the pentaamminecobalt(III) moiety liberates nitrophenolate in basic solution 10 6 -fold faster than the free phosphodiester. The reaction proceeds via attack of coordinated amido ion to yield a four-membered N,O chelate phosphoramidate ethyl ester

Quand la sarcophagine est coordinee a Ru(III) elle subit une deshydrogenation oxydante rapide, qui introduit un groupe imine dans la partie pontante du coordinat. Des oxydations successives donnent le complexe Ru(II)-hexaimine. Donnees cinetiques et thermodynamiques

L'oxydation par le chlore du centre S dans les complexes [Co(en) 2 (NH 2 CH(R)CH 2 S)] 2+ . Formation d'un sulfonate chelate [Co(en) 2 (NH 2 CH(CO 2 H)CH 2 SO 2 O] 2+ . Stereochimie des transpositions

Oxidation of chelated hydroxy-L-proline by thionyl chloride gives substituted dihydropyrroles, which undergo subsequent base-induced elimination to give chelated pyrrole-2-carboxylate complexes.