Atefi Farzad, McMurtrie John C, Arnold Dennis P
Synthesis and Molecular Recognition Program, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, 4001, Australia.
Dalton Trans. 2007 Jun 7(21):2163-70. doi: 10.1039/b703589f. Epub 2007 Apr 19.
Di- and triporphyrin arrays consisting of 5,15-diphenylporphyrinatomagnesium(II) (MgDPP) coordinated to free-base and Ni(II) porphyrinyl mono- and bis-phosphine oxides, as well as the self-coordinating diphenyl[10,20-diphenylporphyrinatomagnesium(II)-5-yl]phosphine oxide [MgDPP(Ph(2)PO)], were synthesised in excellent yields and characterised by various spectroscopic techniques. Phosphine oxides stabilise Mg(II) coordination to porphyrins and the resulting complexes have convenient solubilities, while the Ni(II) complexes exhibit interesting intramolecular fluorescence quenching behaviour. The binding constant of MgDPP to triphenylphosphine oxide (5.3 +/- 0.1 x 10(5) M(-1)) and the very high self-association constant of [MgDPP(Ph(2)PO)] (5.5 +/- 0.5 x 10(8) M(-1)) demonstrate the strong affinity of phosphine oxides towards Mg(II) porphyrins. These complexes are the first strongly bound synthetic Mg(II) multiporphyrin complexes and could potentially mimic the "special pair" in the photosynthetic reaction centre.
