A 1,8-naphthalenediol-based unsymmetrical dinucleating ligand

Dalton Transactions Pub Date: 2005-07-26 DOI: 10.1039/B507579C

Abstract

A facile synthesis of 2-formyl-1,8-naphthalenediol is reported. Its potential as a general precursor for the preparation of unsymmetrical multidentate chelating ligand systems based on 1,8-naphthalenediol is demonstrated by the synthesis of the dinucleating ligand L4? (H4L = N,N′-bis(2-(1,8-naphthalenediol)methylidene)propylenediamine). Reaction of H4L with copper acetate results in the formation of the unsymmetrical dinuclear CuII complex [LCu2] (3), which has been structurally characterized by single-crystal X-ray diffraction. One CuII ion is coordinated by a N2O2 compartment of L4? and the other CuII ion is coordinated by an O4 compartment of L4? while they are bridged by two aryloxide functions of L4?. A dimerization of two molecules of 3 to a tetranuclear entity 32 occurs through formation of weak apical Cu–O interactions. Analysis of the temperature dependent magnetic susceptibility measurements (2–290 K) established a strong intradimer exchange coupling J12 = ?371 cm?1. This strong superexchange interaction fits nicely in a magneto-structural correlation which has been established for dinuclear bis(phenoxide)-bridged CuII complexes demonstrating the electronic equivalence of the aryloxides of a phenol and 1,8-naphthalenediol.

Graphical abstract: A 1,8-naphthalenediol-based unsymmetrical dinucleating ligand
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