Structure and Photosynthetic Mimicking of Bis (2,6‐bis (benzimidazol‐2‐yl) pyridine) manganese (II)

Abstract

Mn( bzimpy )2( 1 ) [ bzimpy = 2, dbis ( benzimidazol-2-yl ) pyridine], a mononuclear manganese(TI) complex, was synthesized by the reaction of Mn ( OOCMe)2 with bzimpy in absolute ethanol. The complex was structurally characterized by elemental analysis, cyclic voltammetry, and X-ray crystallography. In the complex, the manganese-nitrogen distances were different, and the geometry and the metal ion environment showed the distortion. The cyclic voltammetric measurements have been performed to assess its redox characteristics. The presence of oxidation wave at +0.62 V and +0.81 V vs. SCE or +0.8 V and + 1 . 0 V vs. NHE suggested that this complex could catalyze the oxidation of water, therefore, simulate the water-oxidizing complex (WOC) of photosystem II (PS II) . The measurements of photoreduction of 2.6-dichlorophenolindophenol (DCPIP) , and oxygen evolution in the manganese-depleted and the complex 1-reconstituted PS II preparations just support our conjecture. Keywords tal structure, photosynthetic mimiking 2,6-bis( benzimidazol-2-yl)pyridine (bzimpy 1, crys-ter of WOC during photoactivation indicates that the first two manganeses are integrated sequentially followed by the relatively slow attachment of the two additional manganese atoms .7-9 From this point of view, the mononuclear manganese complex may also be able to bring about the sequential addition of four individual manganese atoms and reconstitute WOC .Ligand of the title complex comprises a donor group of relevance to the coordination of metal centers in many biological systems, namely imidazole ( hisdidine ) . Thus, here we report the synthesis, crystal structure and electrochemical characterization of complex 1, Mn( bzimpy)z[ bzimpy = 2,6-bis (benzimidazol-2-yl) py-ridine ] , and its photosynthetic mimicking.

Oligomers with structural elements of imidazolidinetrione obtained from oxamic acid and oxamide: polyurethane foams modified by structural elements of imidazolidinetrione

“…Another method of preparing such polymers has been the use of substrates which allow the formation of heterocyclic rings during the polyreaction, e.g., during preparation of polyimides, polybenzthiazoles [2] or polybenzimidazoles [3][4][5][6]. In a similar way, thermally stable polymers containing parabanic acid rings in their structure (trioxoimidazolidine rings) have been obtained, e.g., with the use of isocyanate cyanoformamidyl [7]:…”