Metal ion-induced self assembly of open-chain tetrapyrrole derivatives: Double stranded dinuclear complexes from 10-oxo-5,15-biladienes
Syntheses of double stranded neutral species via the complexation of Zn, Cd, and Hg with 10-oxo-5,15-biladiene LH2 are described. Formation of the single stranded Cd complex indicates that the self assembly process which affords the double stranded system is not simply a consequence of relief of steric strain. The crystal structure of the cadmium(II) double stranded dimer 8 is described. Long contact distances between carbonyl spacers and Cd ions in the crystal structure of and complete the coordination sphere of each Cd, concomitantly forming two distorted trigonal bipyramidal metal centers. Fast coordination/decoordination phenomena involving the carbonyl spacers and the two metallic centers in the zinc(II), cadmium(II) and mercury(II) dimeric complexes 7, 8 and 9, respectively, are investigated by using variable temperature 1H NMR. A bending/twisting process is proposed, and its associated energy barrier (40-50 kJ mol-1) is determined for the first time.
Publication Source (Journal or Book title)
Khoury, R., Jaquinod, L., & Smith, K. (1998). Metal ion-induced self assembly of open-chain tetrapyrrole derivatives: Double stranded dinuclear complexes from 10-oxo-5,15-biladienes. Tetrahedron, 54 (11), 2339-2346. https://doi.org/10.1016/S0040-4020(98)00003-9