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

The synthesis and physical properties of the ternary complex 3(2+), prepared by reaction of a naphthalene diimide dicarboxylate 2 with the binucleating dinickel(II) cavitand 1, are discussed. The complex 3(2+) 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 3(2+) in CH2Cl2 compared to the components 4+ and 5, respectively, are used to characterise the complex further. In particular there is a substantial quenching (approximately 95%) of the diimide fluorescence upon complexation. X-Ray crystallography has been used to characterise complex 3(2+) in the solid state. Of particular interest is the supramolecular structure in which the naphthalene diimide is included between the two metallocavitand hemispheres.