Ternary complexes composed of naphthalene diimides and binucleating metallocavitands: preparation, characterisation and structure of [(Ni2L)2(NDI)][BPh4]2

Abstract

The synthesis and physical properties of the ternary complex 3²⁺, prepared by reaction of a naphthalene diimide dicarboxylate 2 with the binucleating dinickel(II) cavitand 1, are discussed. The complex 3²⁺ is characterised by cyclic voltammetry which shows a wealth of metal-centred and diimide-based processes at −1.62, −1.04 and 0.15 V vs Fc/Fc⁺. Absorption and fluorescence spectroscopy of 3²⁺ in CH₂Cl₂ compared to the components 4⁺ and 5, respectively, are used to characterise the complex further. In particular there is a substantial quenching (∼95%) of the diimide fluorescence upon complexation. X-Ray crystallography has been used to characterise complex 3²⁺ in the solid state. Of particular interest is the supramolecular structure in which the naphthalene diimide is included between the two metallocavitand hemispheres.