H2O2 reactivity of a dinuclear copper(II) complex incorporating a constrained binucleating polyaminopyridyl ligand and a phosphodiester coligand

作者：Siluvai Gnana S^*; Vargheese Babu; Murthy Narasimha N

来源：Inorganica Chimica Acta, 2011, 375(1): 93-100.

DOI：10.1016/j.ica.2011.04.031

• Dicopper center
• Phosphodiester bridge
• Hydroperoxide intermediate
• C-H bond activation
• X-ray crystal structure and paramagnetic H-1
• NMR

A dinuclear copper(II) complex [Cu-2(PD)(DPP)(2)](ClO4)(2) (1) incorporating a constrained binucleating hexadenate ligand, PD (1,3-bis{bis[(2-pyridyl)ethyl]amino}benzene), and coligand, DPP (diphenylphosphate) was synthesized and characterized, with a specific outlook towards evaluating spectroscopic and H2O2 reactivity relevant to the active-sites of noncoupled dinuclear copper enzymes, D beta M and PHM. In solution, complex 1 exhibits a broad H-1 NMR in the range -25 to +60 ppm and has a solution magnetic moment (mu) of similar to 2.0 B.M./Cu(II), typical of a noninteracting dicopper(II) center. The room temperature H2O2 reactivity of 1 monitored by UV-Vis spectroscopy reveals the formation of a copper(II)-dioxygen intermediate 1a, which in turn leading to a arene ligand hydroxylation (PD-O) and thus provide a new doubly-bridged dicopper(II) complex, [Cu-2(PD-O)(DPP)](ClO4)(2) (2). The dioxygen intermediate produces O=PPh3 on treatment with PPh3 revealing it is an electrophilic hydroperoxide oxidant. Solution magnetic moment of 1.61 B.M./Cu(II) indicates the product complex 2 is a moderately interacting dicopper(II) center and its H-1 NMR spans between -20 and +180 ppm. A comparison of the optical absorption features of complex 1a with related dinuclear hydroperoxo-copper(II) complexes is discussed.

• 出版日期2011-9-1