Homo- and Hetero-Dinuclear Anion Complexes

✍ Scribed by Michela Allevi; Marco Bonizzoni; Luigi Fabbrizzi

• Book ID: 101838091
• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 457 KB
• Volume: 13
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200601682

✦ Synopsis

Abstract

The tripodal system 4, in which urea fragments are appended to the three terminal amine nitrogen atoms of a tris(2‐aminoethyl)amine (tren) subunit, includes a Cu^II^ ion and two anions X^−^, according to a cascade mechanism through three well defined stepwise equilibria in a DMSO solution. The first anion X^−^ (halide, N~3~^−^, NCS^−^, NO~2~^−^, H~2~PO~4~^−^) seeks the Cu^II^ centre coordinated by the tren moiety; the second anion X^−^ interacts with the trisurea cavity, but this occurs only if the stronger H‐bond acceptors, such as N~3~^−^ and H~2~PO~4~^−^, are used. Binding of the second X^−^ ion is favoured by the preorganising effect exerted by the metal and disfavoured by the steric and electrostatic repulsions between the anions. Under the appropriate conditions, heterodinuclear complexes of formula [Cu^II^(4)(Cl)(H~2~PO~4~)] can be obtained in solution, in which Cl^−^ is bound to the metal centre and H~2~PO~4~^−^ interacts with the trisurea compartment.