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Lookup NU author(s): Professor Andrew Benniston,
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A simple synthetic procedure for the mono- or di-functionalization of tri- and tetra-azamacrocycles with electron rich arenes has been developed. Specifically, 1,4,7-triazacyclononane (tacn), 1,4,7,10-tetraazacyclododecane (cyclen) and 1,4,8,11-tetraazacyclotetradecane (cyclam) react with 2,4,6-trimethylstyrene in the presence of n-butyllithium to give, respectively N-(mesitylethyl)-1,4,7-triazacyclononane (L1), N-(mesitylethyl)-1,4,7,10-tetraazacyclododecane (L4), and N-(mesitylethyl)-1,4,8,11-tetraazacyclotetradecane (L5). In contrast, when styrene itself or p-vinylanisole are used as the Michael acceptor with 1,4,7-triazacyclononane, the N′,N″ product is formed, respectively N′,N″-bis(phenylethyl)-1,4,7-triazacyclononane (L2) and N′,N″-bis(p-methoxyphenylethyl)-1,4,7-triazacyclononane (L3). Using conventional mono-functionalization techniques, the phenyl derivatives N-(4-hydroxymethylbenzyl)-1,4,7-triazacyclononane (L6) and N-(4-benzylcarboxylic acid)-1,4,7-triazacyclononane (L7) have also been synthesised. A series of transition metal complexes of L1 to L7 with Ni(II), Cu(II), Zn(II) and Co(II) have been prepared. The X-ray crystal structures of [Cu(L1)2](PF6)2, [(L1)CuCl2], [Cu(L6)(NO3)2] and [Cu2(L7-H)2(OH2)2] (PF6)2·3H2O are described. In all of these complexes, coordination to the metal takes place through the macrocycle nitrogens. The crystal structure of [Cu2(L7-H)2(OH2)2] (PF6)2·3H2O reveals that it is a coordinate-polymeric material. Attempts to coordinate the pendent arenes to Rh(I) are discussed. © 2002 Elsevier Science Ltd. All rights reserved.
Author(s): Benniston AC, Ellis D, Farrugia LJ, Kennedy R, Peacock RD, Walker S
Publication type: Article
Publication status: Published
ISSN (print): 0277-5387
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