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Metal complexes of macrocyclic ligands. Part XXXVII. Synthesis of Heteroditopic Bis‐macrocycles and Their Potential for Preparing Heterobinuclear Metal Complexes

 

作者: André Urfer,   Thomas A. Kaden,  

 

期刊: Helvetica Chimica Acta  (WILEY Available online 1994)
卷期: Volume 77, issue 1  

页码: 23-35

 

ISSN:0018-019X

 

年代: 1994

 

DOI:10.1002/hlca.19940770105

 

出版商: WILEY‐VCH Verlag GmbH

 

数据来源: WILEY

 

摘要:

AbstractA new and generally applicable synthetic path for the preparation of heteroditopic bis‐macrocycles using tri‐N‐protected tetraazacycloalkanes as building blocks and bromoacetyl bromide as bridging reagent is described. In the first step, bromoacetyl bromide is used as acylating agent for one of the macrocycles, whereas in the second step it is used as alkylating agent for the second macrocycle, thus giving protected bis‐macrocyclic amides (e.g.6). After reduction of the amide moiety and deprotection, bis‐azamacrocycles with an ethylene bridge are obtained (e.g.8). The corresponding homoditopic bis‐macrocycles16and17are also prepared for comparison purpose. Spectrophotometric studies indicate that bis‐macrocycle8, which consists of a 12‐ and a 14‐membered ring, binds two metal ions with equal affinity, whereas compound13, in which an unsubstituted (cyclam) and a trimethyl‐substituted tetraazacyclotetradecane unit (Me3cyclam) are bridged, shows selective metal‐ion binding. The first metal ion is always incorporated into the cyclam unit, whereas the second one binds to the Me3cyclam macrocycle. Thus, by sequential addition of two different metal ions, heterobinuclear complexes can easily be prepared. The electrochemistry of the binuclear Ni2+complexes, studied by CV and DPV, as well as the EPR spectra of the binuclear Cu2+complexes clearly indicate met

 

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